taxonID	type	description	language	source
05062C5440639E3B076D4A87FC1CFE20.taxon	type_taxon	Type species Orchomenopsis chevreuxi Stebbing, 1906, original designation.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440659E2507404CB5FCB2FEDB.taxon	description	Figs 2 – 9	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440659E2507404CB5FCB2FEDB.taxon	diagnosis	New diagnosis Pereonites 1 – 7 and pleonites 1 – 2 with a weak but distinct dorsoposterior hump on each segment. Lateral cephalic lobe broadly rounded, dorsal margin regularly convex and slightly more convex than the nearly straight ventral margin. Antennae 1 – 2 of male with calceoli, female without. Epistome level with upper lip. Maxilla 1 palp, distal end weakly convex with conical apical spines contiguous. Maxilliped inner plate, distal margin conspicuously excavate; outer plate inner margin not scalloped. Coxa 1 slightly widened distally, ~ 1.2 – 1.3 × proximal width. Gnathopod 2 propodus of male and female narrow, length ~ 2.3 – 2.5 × width, dactylus very small, inserted on the posterodistal one-third of distal margin, palm lacking concavity. Coxa 5 very weakly posterolobate, posterodistal lobe narrow with posterodistal margin nearly straight. Pereopod 7 basis with anterior margin slightly concave, posterior margin subparallel to anterior margin in the proximal two-thirds, distal third with a distinct, nearly straight bevel (male less distinct and more rounded). Uropod 1 peduncle length greater than 1.5 – 1.7 × length of outer ramus. Uropod 3 inner ramus extends past distal end of article 1 and reaches ~ 70 % length of article 2 of outer ramus. Telson cleft ~ 52 – 56 % of length.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440659E2507404CB5FCB2FEDB.taxon	materials_examined	Material examined Holotype SOUTHWEST ATLANTIC • ♂ (7.5 mm, figured, see Figs 5 – 9, dissected in 3 tubes, carcass missing / lost); east of Buenos Aires; HMS Challenger, station 323; 35 ° 39 ′ S, 50 ° 47 ′ W; depth 3475 m (1900 fathoms); bottom blue mud, temperature 33.1 ° F; 28 Feb. 1876; BMNH 1889.5.15.23 Additional material SOUTHWEST ATLANTIC • 1 ♀ (9.5 mm, mature, with setose brood plates, illustrated, see Figs 2 – 4, appendages on 2 slides); Argentine Basin; RV Meteor DIVA- 3 M 79 / 1 expedition, station 531; 35 ° 56.49 ′ S, 48 ° 53.85 ′ W; depth 4586 m; gear, baited traps; 15 Jul. 2009; E. Hendrycks leg.; ZMH K- 61206 • 1 ♂ (7.0 mm, appendages on 2 slides, partly illustrated, see Fig. 2); same collection data as for preceding; ZMH K- 61207 • 5 ♂♂, 5 ♀♀, 4 juveniles; same collection data as for preceding; ZMH K- 61208 • 10 ♂♂, (one of these 7.0 mm, dissected, appendages on 3 slides), 5 ♀♀, 7 juveniles; same collection data as for preceding; CMNC 2022 - 0001 • 5 ♂♂, 10 ♀♀, 3 juveniles; same collection data as for preceding; RBINS INV. 138.486. NORTH ATLANTIC • 9 ♀♀ (with mature ♀♀, 7 – 10 mm, 1 mature ♀, 10 mm, appendages on 8 slides, 1 nearly mature ♀, 9.5 mm, appendages on 3 slides); near Azores; Hirondelle 1896 campaign, station 730; 37 ° 58 ′ N, 28 ° 33 ′ 30 ″ W; depth 2660 m; bottom sandy clay; gear, baited traps; 3 – 5 Aug. 1896; MNHN, collection Chevreux (no registration number, see Chevreux 1903: 92).	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440659E2507404CB5FCB2FEDB.taxon	description	Description Female Based on female (mature), 9.5 mm (ZMH K- 61206). PEREONITES 1 – 7 AND PLEONITES 1 – 2 (Fig. 2). With weak but distinct dorsoposterior hump on each segment. PLEONITE 3 (Fig. 2). With a distinct, rounded posterodorsal elevation slightly overhanging urosomite 1. COXAE 1 – 2 (Figs 2 – 3). Subequal to slightly longer (1.1 × to 1.25 ×) than the depth of corresponding pereonites (in lateral view). COXAE 3 – 4 (Fig. 4). Slightly longer (1.1 × to 1.25 ×) than the depth of corresponding pereonites, coxa 3 not shown. EPIMERON 3 (Fig. 2). Subquadrate, with posterodistal angle slightly obtuse, apex rounded, posterior margin weakly but regularly convex, ventral margin regularly convex. UROSOMITE 1 (Fig. 2). With a deep, narrow dorsal concavity in front of the strong, regularly rounded dorsal boss, convex on posterior margin, boss projecting strongly upright and backward, slightly overhanging urosomite 2. HEAD (Fig. 2). About equal in length to pereonite 1. LATERAL CEPHALIC LOBE (Fig. 2). Broadly rounded; dorsal margin regularly convex and slightly more convex than the nearly straight ventral margin. EYE (Fig. 2). Nearly indistinguishable, but non ommatidial, formed of pigment granules; crescent-shaped, narrow, parallel to head anterior margin (estimated in figure by dotted outline). ANTENNA 1 (Fig. 2). Peduncular article 1 without anterodistal lobe, slightly dilated, length about 1.4 × width; flagellum 10 - articulate, first article of flagellum callynophorate, densely furnished with double row of aesthetascs medially, callynophore small, shorter (67 %) than the remaining articles combined; accessory flagellum 5 - articulate, first article slightly shorter (80 %) than remaining articles combined; calceoli absent. ANTENNA 2 (Fig. 2). Slightly longer than antenna 1; geniculate between peduncular articles 3 – 4, peduncular articles 4 – 5 lined with anteromedial brush setae; flagellum 12 - articulate, calceoli absent. EPISTOME (Fig 2). Level with the upper lip, from which it is separated by a small slit and weak shallow indentation; weakly concave above upper lip. UPPER LIP (Fig. 2). Anterior margin convex, not protruding; midventral margin with a small, angular projection. MANDIBLE. Incisor distinctly convex and slightly widened, dorsolateral and ventromedial corners with small tooth; left lacinia mobilis slender, curved, distally with small teeth, right lacking; accessory spine row with 3 strong spines, interspersed with fine setae; molar somewhat falciform, not columnar, forming a narrow crest, acutely produced on proximal end, setose with small triturative surface, hairy process (cf. Oleröd 1975) located proximal to molar; palp attached proximal to molar; article 2 with 15 A 2 setae, article 3 missing (refer to Fig. 6 of male holotype for general morphology and setae details). LOWER LIP. Outer lobes broad, inner margins strongly setose, distal inner margins excavated; without inner lobes; mandibular processes rounded. MAXILLA 1 (Fig. 2). Outer plate with 11 spine-teeth in 7 / 4 crown arrangement; palp article 2 widened, with 9 contiguous (or nearly contiguous, separated by much less than the width of a spine) distal conical spines and one apical strong seta on outer corner; inner plate short with subrounded apical projection, and two unequally sized plumose setae inserted subapically (refer to Fig. 7 of male holotype for general morphology). MAXILLA 2. Outer and inner plates strongly tapering distally, both lined with strong rows of pectinate medial marginal spines and setae; inner plate much shorter and slightly narrower than outer plate, apex just reaching the proximal end of medial setal row of outer plate (refer to Fig. 7 of male holotype for general morphology). MAXILLIPED (Fig. 2). Inner plate short, reaching about one third length of outer plate and reaching half length of palp article 1; outer corner of inner plate reaching about the level of the basal insertion of palp article 2; inner plate, distal margin conspicuously excavate, with slight mediodistal extension protruding slightly higher than the outer corner, with 3 weakly protruding nodular spines, unequally spaced, the two inner nodular spines closer to each other, the third nodular spine at the bottom of the excavation; outer plate well developed, subovate, length 1.8 × width, distal margin of outer plate reaching slightly below the distal margin of palp article 2, with two dissimilar apical spines and numerous (~ 12) strongly embedded, medial nodular spines, medial margin nearly smooth; palp strongly setose medially, article 4 well developed, about 60 % of the length of article 3, with few apical fine setae on inner margin (refer to Fig. 7 of male holotype for general morphology). GNATHOPOD 1 (Fig. 3). Coxa moderately widened, distal width 1.3 × proximal width and about 72 % of length; anterior margin weakly concave; posterior margin very slightly concave, nearly straight; distal margin slightly convex in posterior half, more strongly convex in anterior half; basis stout, as wide as propodus, anterior margin with 7 very short setae; ischium subequal to merus; carpus short, less than half the length of propodus, posterodistal lobe not guarding propodus; propodus subchelate, subrectangular, very weakly tapering, length 1.57 × width, posterior margin slightly concave with distinct inflexion point at about distal two-thirds; palm slightly convex, with irregular microserrations, palm corner with 2 blunt protrusions and defined by 1 medial and 1 lateral spine; dactylus barely overriding palm corner. GNATHOPOD 2 (Fig. 3). Coxa subrectangular, length 2.36 × width, anterior margin nearly straight, posterior margin slightly concave, distal margin straight; ischium shorter than carpus; carpus length 1.8 × propodus; propodus chelate, surface finely setose with distal groups of long pectinate setae, slender, length 2.45 × width, much narrower (0.6 ×) than carpus, ventral margin very slightly concave, nearly straight; dactylus very small, inserted on the posterodistal one-third of distal margin, with distal microornamentation, palm not excavate. PEREOPOD 3. Coxa subrectangular, with anterior margin nearly straight, posterior margin slightly concave, length 2.4 × width; rest of pereopod as in pereopod 4. PEREOPOD 4 (Fig. 4). Coxa length 1.38 × width, posterior margin strongly excavate, with strong, subtriangular posterodistal lobe, angle subquadrate and apex rounded, posterior corner located at distal 66 % of the length; posterior margins of ischium-merus-carpus with clusters of long setae; propodus with 6 short spine groups; dactylus 0.44 × length of propodus. PEREOPOD 5 (Fig. 4). Coxa slightly wider (1.15 ×) than long, very slightly posterolobate, posterodistal lobe narrow, not regularly convex, with posterodistal margin nearly straight; basis shorter than coxa, length 0.84 × coxa, length 1.12 × width, posterodistal lobe broadly rounded, slightly surpassing the distal margin of ischium; merus slightly expanded, width 0.7 × length, bearing anterior and posterior setae; rest of pereopod missing. PEREOPOD 6. Basis weakly narrowing distally, with posterior margin slightly serrate and regularly convex, anterior margin nearly straight on 80 % of its length, length 0.70 × the combined length of the remaining articles, posterodistal lobe not reaching distal margin of ischium; merus slightly expanded (narrower than in P 5) and bearing few anterior and posterior setae; propodus slightly shorter than merus-carpus, with 6 clusters of short spines; dactylus about 0.3 × length of propodus. PEREOPOD 7 (Fig. 4). Coxa small, subovate; basis with anterior margin slightly concave, posterior margin subparallel to anterior margin in the proximal two-thirds, distal third with a distinct, nearly straight bevel; posterior margin with 10 – 11 weak serrations; posterodistal lobe not extending to distal margin of ischium; merus not expanded (narrower than P 6), anterior margins of merus-carpus with short spine groups, posterior margin bearing few short slender spines; propodus slightly shorter than merus-carpus; dactylus 0.35 × length of propodus. UROPOD 1. Peduncle relatively long, about 1.5 × length of outer ramus and 1.7 × length of inner ramus, dorsolateral and dorsomedial margins spinose (with 14 dorsomedial spines); inner ramus slightly shorter than outer, margins of rami poorly spinose, with slender spines, medial margin of outer ramus lacking spines (refer to Fig. 9 of male holotype for general morphology). UROPOD 2 (Fig. 2). Peduncle 1.27 × length of outer ramus, with 5 closely spaced spines on distal outer margin, inner margin with 3; inner ramus shorter than outer ramus; outer ramus with 6 equally spaced thin sharp spines on dorsolateral margin; inner ramus margins with small slender spines. UROPOD 3 (Fig. 2). Peduncle 0.79 × length of biarticulate outer ramus; second article of outer ramus long, about 0.5 × length of article 1; inner ramus extends past distal end of article 1 and reaches ~ 70 % of article 2 of outer ramus; inner margins of rami with long plumose setae and few spines. TELSON (Fig. 4). 1.6 × longer than wide, cleft (52.5 %), lobes tapering distally with 4 – 5 lateral, submarginal spines and 1 distal spine. GILLS 5 – 6. With 1 long tubular accessory lobe on gill 5 and 2 on gill 6, inserted basally. GILL 7 (Fig. 4). Present, well developed. BROOD PLATES (Figs 3 – 4). On gnathopod 2 and pereopods 3 – 5, long, slender and curved distally, largest on gnathopod 2 and pereopods 3 – 4, with long brood setae, 16 setae on gnathopod 2 plate and 15 on pereopod 4. STOMODEUM. Extending to the 7 th pereonite. Male Based mostly on 7.5 mm holotype, Figs 5 – 9 (BMNH 1889.5.15.23) and 7 mm male (ZMH K- 61207) specimens (Fig. 2 for head and body characteristics). Similar to female, but differing as follows: BODY. Smaller than female and slightly less robust. LATERAL HEAD LOBE (Fig. 2). Slightly narrower. ANTENNA 1 (Figs 2, 5). Peduncular article 1 stouter, more compact; callynophore stronger, about as long or slightly longer than the remaining flagellar articles, flagellum 12 – 13 - articulate, articles shorter, slightly setose, with calceoli. ANTENNA 2 (Figs 2, 5). Slightly longer (1.25 ×) than antenna 1; flagellum 13 – 16 - articulate, with calceoli. COXA 1 (Figs 2, 8). Weakly widened distally, less than in female, distal width 1.25 × proximal width and 60 % length, anterior margin and posterior margins very slightly concave at midpoint. COXA 2 – 4 (Fig. 9). Distinctly narrower than in female, coxa 4 length 1.5 × width. MANDIBLE (Fig. 6). Incisor distinctly convex and slightly widened, dorsolateral and ventromedial corners with small tooth; left lacinia mobilis curved, with 2 strong and 1 weak apical teeth, right lacking; accessory spine row with 3 strong spines, interspersed with fine setae; molar forming a narrow crest, somewhat falciform, acutely produced on proximal end, setose with small triturative surface; hairy process (cf. Oleröd 1975) located proximal to molar; palp attached proximal to molar; article 2 1.58 × length of article 3, with 20 A 2 setae, article 3 straight, slightly falciform, with 1 A 3 seta, a long rank of 20 D 3 - pectinate marginal setae and 2 E 3 seta. LOWER LIP. Outer lobes broad, inner margins strongly setose, distal inner margins excavated; without inner lobes; mandibular processes rounded. MAXILLA 1 (Fig. 7). Outer plate with 11 spine-teeth in 7 / 4 crown arrangement; palp article 2 very weakly widened, with 8 distal conical spines and one apical strong seta on outer corner; inner plate with short subacute apical projection, and two unequally sized plumose setae inserted subapically. MAXILLA 2 (Fig. 7). Outer and inner plates strongly tapering distally, both with strong rows of pectinate medial marginal spines and setae; inner plate much shorter and narrower than outer plate (narrower than female), apex just reaching the proximal end of medial setal row of outer plate. MAXILLIPED (Fig. 7). Inner plate short, reaching about 0.3 × length of outer plate and reaching half length of palp article 1; outer corner of inner plate reaching about the level of the basal insertion of palp article 2; inner plate, distal margin conspicuously excavate, slight mediodistal extension about equal to outer corner (lower than female), with 3 weakly protruding nodular spines, unequally spaced, the two inner nodular spines closer to each other, the third nodular spine at the bottom of the excavation; outer plate well developed, subovate, length 1.8 × width, distal margin of outer plate slightly shorter than distal margin of palp article 2, with two dissimilar apical spines and numerous (9 – 10) strongly embedded, medial nodular spines, medial margin nearly smooth; palp strongly setose medially, article 4 well developed, about 60 % of the length of article 3, with 3 apical setae on inner margin (note: medial marginal setae omitted on palp of Mxpd). GNATHOPOD 1 (Fig. 8). Basis narrower than propodus width, anterior margin with only 1 short seta; propodus of similar proportions to female, length 1.55 × width, but posterior margin slightly less concave. GNATHOPOD 2 (Fig. 8). Propodus of similar shape and proportions to female, length ~ 2.3 × width. PEREOPOD 5 (Fig. 9). Coxa slightly more posterolobate; basis slightly longer, length 1.17 × width. PEREOPOD 7 (Fig. 9). Basis, posteroventral bevel not as distinct or as straight. UROPOD 1 (Fig. 9). Peduncle long, about 1.7 × length of outer ramus and 1.9 × length of inner ramus, dorsolateral and dorsomedial margins spinose; inner ramus shorter than outer, margins of rami poorly spinose, with slender spines, medial margin of outer ramus lacking spines. UROPOD 2 (Figs 2, 9). Distolateral marginal spines of peduncle grouped closely together at distal end of peduncle; inner ramus distinctly shorter than outer; outer ramus distolateral spines stouter, more numerous, bluntly rounded and more closely spaced distally, proximal spine acute (see comments, p. 24). UROPOD 3 (Fig. 9). Second article of outer ramus shorter than female, about 0.34 × length of article 1. UROSOMITE 1 (Fig. 2). Dorsal concavity broader, boss slightly narrower, posterior margin less convex. TELSON (Fig. 9). Cleft deeper (56 %) than female.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440659E2507404CB5FCB2FEDB.taxon	distribution	Distribution Southwest Atlantic: Argentine Abyssal Basin (Stebbing 1888; this paper), Northeast Atlantic abyssal plains (Chevreux 1903). Pacific deep-sea (Dahl 1959; Birstein & Vinogradov 1960; Barnard & Ingram 1990; Lowry & Stoddart 1994; Lacey et al. 2016) and Indian Ocean occurrences (Birstein & Vinogradov 1964; Witte 1999; Janssen et al. 2000) remain to be confirmed. No co-occurrence with A. patriciae sp. nov. was documented so far. Depth range Bottom records: 3475 m (Stebbing 1888) to 4586 m (this paper). Midwater records: 2178 m from the surface (Chevreux 1903). Along with A. scotianensis and A. shannonae sp. nov. (see below), A. abyssorum is one of many scavenging amphipods recorded so far by midwater trawls at some distance from the bottom. Other documented cases include A. chevreuxi (Stebbing, 1906); A.? distinctus (Birstein & Vinogradov, 1960); Cyclocaris sp.; Eurythenes sp.; Paralicella caperesca Shulenberger & Barnard, 1976; P. tenuipes Chevreux, 1908; Scopelocheirus sp. and Valettieta gracilis Lincoln & Thurston, 1983: see Thurston 1990. As well as: Pseudorchomene coatsi (Chilton, 1912); A. plebs (Hurley, 1965); A. rossi (Walker, 1903) and Orchomenella cavimanus (Stebbing, 1888): see De Broyer et al. 2007.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440659E2507404CB5FCB2FEDB.taxon	discussion	Remarks Orchomene abyssorum was described by Stebbing (1888), from a single male specimen (about 7.5 mm long) collected by the HMS Challenger in the Argentine Basin at a depth of 3475 m. As shown by the extensive citation list, Abyssorchomene abyssorum has been widely reported and is generally considered as having a wide-ranging, even cosmopolitan distribution (Barnard & Ingram 1990; Thurston 1990, 2001; Barnard & Karaman 1991; Duffy et al. 2013), but this concept is being challenged and will change with our study. There are still many questions regarding species identity of single specimens which await confirmation by critical study of the material. We examined and refigured the male holotype specimen (appendages and mouthparts; the carcass is apparently lost). As a result, we have noticed some obvious discrepancies between our observations and drawings, and the original illustrations of Stebbing. Some of these are as follows (Stebbing’s differences are outlined in parentheses): antenna 1 peduncular article 1 dorsal margin is less convex and the ventral margin is less concave (vs dorsal margin strongly convex, ventral margin strongly concave); mandible palp article 3 is straighter (vs strongly curved and more falciform); maxilla 1 palp is shorter, less curved with the distal margin straighter (vs palp longer, more strongly curved with distal margin strongly convex); maxilla 2 outer plate broader (1.35 ×), (vs very narrowed, much less than width of inner plate); maxilliped outer plate shorter, with inner margin nearly straight (vs outer plate longer, with inner margin concave and strongly serrated); gnathopod 1 propodus is broader (length 1.5 × width) with a short carpal lobe (vs longer, length 2 × width and more curved, with a longer carpal lobe, strongly guarding the hind margin); gnathopod 2 propodus has a very slight concave ventral margin, with a small dactylus and the posterodistal margin is slightly convex (vs strongly concave ventral margin, with a larger dactylus and the posterodistal margin is strongly sloped, level with the dactylus); epimeron 3 is narrowly rounded at the posteroventral corner (vs more broadly rounded at the posteroventral corner) and the dorsal boss of urosomite 1 is narrowly rounded and more upright (vs broadly rounded and lower). There are other minor differences which we have not included here. Reasons for these discrepancies are most likely numerous but possibly related to microscopy drawing technique and available equipment, attention to various details and whether these were completed freehand in some cases. A special dimorphic character has been found in the male uropod 2 outer ramus distolateral spines. They are in a comb-like arrangement and are much stouter and bluntly rounded, more numerous and more closely spaced distally, with the proximal spine (s) being acute. This morphology and arrangement of ramal spines are not found in females, which are always acute, slender and more evenly spaced. The function of this peculiar spine morphology and arrangement in males are unknown, but possibly related to mating. All male specimens of Abyssorchomene discussed present this uropod 2 outer ramus spine character and it has not been reported or elaborated in the literature as far as we know (see Figs 2, 9, 17, 25, 33). Part of the material identified by Chevreux (1903) from the Hirondelle campaign 1896 (station 730 near the Azores, depth 2660 m) was also examined. It consisted of nine female specimens including fully mature ones. These specimens present all the diagnostic characters of Abyssorchomene abyssorum as redescribed here (in particular, the weak dorsal corrugations – sometimes difficult to distinguish – and the narrow female gnathopod 2 propod without an excavate palm), confirming Chevreux’s identification. The rest of Chevreux’s material (1935) collected from some other North Atlantic abyssal regions has not been seen and remains to be carefully checked. Walker (1903) recorded three specimens of which one is registered in the Natural History Museum (London) collections: BMNH 1905.9.7.23: one specimen, 6 mm, non-gravid, without visible oostegites, male (?), with gnathopod 2 propod length more than twice the width and palm straight, without a proximal concavity (Lauren Hughes, pers. com.), which does not allow to differentiate it from the male of A. patriciae sp. nov. In his paper, Walker did specifically thank Stebbing for verification of his Orchomene abyssorum identification, but we consider this identification as uncertain. We also checked the single specimen identified by Stephensen (1925) from the Ingolf 1895 – 96, station 91, North Atlantic, west of Iceland, 64 ° 44 ′ N, 31 ° 00 ′ W, depth 2317 m, bottom 3.1 ° C, held in the Zoological Museum, University of Copenhagen (ZMUC). The specimen is fragmentary and in poor condition, with the head missing. We recognise it as a male. The slender gnathopod 2 propodus was used by Stephensen to attribute the specimen to Orchomenopsis abyssorum, but this male character is shared by all species of the A. abyssorum complex. So, due to the poor and incomplete condition of this specimen, the definitive identification remains unclear. Dahl (1959) discussed a 12 mm female specimen from the Galathea station 649, southwest Pacific, Kermadec Trench, 35 ° 16 ′ S, 178 ° 40 ′ W, depth 8210 – 8300 m, grey clay with pumice, 14 February 1952, also held in the ZMUC collections, but unfortunately provided no figures. We examined his material and found that it differs from A. abyssorum by the more strongly expanded coxa 1, the proportionally shorter propodus of gnathopod 1, the wider, subovate propodus of gnathopod 2 and the strongly convex distal margin of maxilla 1 palp. As well, this material comes from much greater depths than A. abyssorum. We conclude that it is possibly a new species of Abyssorchomene. From the figures and comments provided by Birstein & Vinogradov (1960), including the first detailed reference to a female (from the Kermadec Trench), we are of the opinion that their specimens differ in many characters from A. abyssorum as redescribed here. We have not seen this material. The figures show that these specimens differ in the following ways: in the more elongate carpal lobe of gnathopod 1 slightly but distinctly guarding the propodus, the proportionally smaller and narrower male gnathopod 1 propodus, the more elongate carpus of gnathopod 2, the distinctly curved propodus of gnathopod 2, the slightly spaced terminal spines on the maxilla 1 palp, the slightly different shape of the pereopod 7 basis with the hind margin parallel to the anterior margin on two-thirds of its length, the shorter inner ramus of uropod 3 and the sinuous inner margins of the telson lobes. Contrary to Barnard & Ingram (1990), we doubt that these morphological differences in the Kermadec Trench specimens can be considered as intraspecific variations of A. abyssorum. Until these specimens are examined in detail, the species attribution remains unknown. Birstein & Vinogradov (1964) collected, in the Central Indian Ocean, a male (8 mm) that we cannot attribute with certainty to A. abyssorum, as there were no illustrations of the specimen and we were not able to examine the material to confirm its identity. Barnard & Ingram (1990) redescribed in detail A. abyssorum based on new material (a single small male, 6.41 mm, Scripps Institution of Oceanography (SIO), station 882, Galapagos Vents area, 00 ° 47.9 ′ N, 86 ° 09.2 ′ W, depth 2491 m). They considered Chevreux’s (1900, 1903, 1935) North Atlantic material, as well as Birstein & Vinogradov's (1960) records as the only firm identifications of A. abyssorum. The small male described and finely illustrated shows the gnathopod 1 carpal lobe slightly more elongate and guarding the propodus to a greater degree than on the type and DIVA- 3 specimens. The pereopod 5 basis has a slightly different relative length: it is shorter than the coxa instead of longer in the type specimen and the DIVA- 3 males. This shape is closer to that of the DIVA- 3 female described here and may be due to the immature state of the specimen. The epimeron 3 shows a slightly sinuous posterior margin which is very slightly and regularly convex, but nearly straight in the type, DIVA- 3 and Chevreux’s material. Like Stebbing (1888), Barnard & Ingram (1990) did not mention the presence of the weak dorsal corrugations, clearly distinct on our DIVA- 3 material and slightly less so in Stebbing’s figure of pleonites 1 – 2, but not on the pereonites on his in-toto illustration. Other minor differences between the male described by Barnard & Ingram (1990) and the type and DIVA- 3 male specimens include: the shorter extension of the poorly distinct eye, i. e., 44 % of the head height instead of 75 % (a character however unclear and somewhat unreliable in long preserved specimens); the much narrower lateral head lobe; the coxa 4, with a very different shape and smaller posteroventral lobe; the coxa 5 width subequal to its height (instead of slightly wider than high); the much shorter inner ramus of uropod 3; the maxilla 2 with tip of inner plate not reaching the basal end of outer plate setal row and the nodulous apical spines of the maxilliped inner plate located differently. Given all these differing characters, it is unlikely to belong to A. abyssorum and at this time the specific attribution of this single male specimen remains unresolved. Thurston (1990) collected A. abyssorum in four North Atlantic abyssal plains by bottom traps or midwater trawls but didn’t make any morphological comment. It is important to note that not all the specimens in this paper were seen by Thurston (Tammy Horton, pers. com.). However, T. Horton (pers. com.) checked the sample from the Porcupine Abyssal Plain (see Table 1) and concluded it belongs to A. patriciae sp. nov. This likely applies to all the samples examined by Thurston 1990. Concerning the Southern Ocean material attributed to A. abyssorum (Schellenberg 1926; Barnard 1932; Nicholls 1938; Dahl 1954), Dahl (1959) expressed his doubts about its conspecifity with A. abyssorum (Stebbing 1888). Andres (1983) definitively distinguished the Antarctic continental shelf specimens from the abyssal and hadal ones in describing A. scotianensis. He considered the juvenile specimens of Schellenberg (1926) as belonging to his new species but couldn’t confirm the affiliation of the specimens of Barnard (1932), Nicholls (1938) and Dahl (1954), as the length-width relationship of coxa 1 and of the basis-propodus of gnathopod 1 were not described. All A. abyssorum identifications should be carefully checked by considering the new species described here. In Table 1, we tentatively attribute the various records to the most likely correct species determined by our study. Abyssorchomene abyssorum shares with the two new species, A. patriciae sp. nov. and A. shannonae sp. nov. dorsodistal corrugations on the pereonites 1 – 7 and pleonites 1 – 2, a character unique among all the species of the genus Abyssorchomene (sensu Lowry & Kilgallen 2014; Horton et al. 2021). This character separates this complex from the remaining Abyssorchomene species. All three species are very close morphologically and males are very difficult to separate. In A. abyssorum, the gnathopod 2 propod, similar in both sexes, is very slender (length 2.3 – 2.5 × width) and the palm presents a very narrow gap and lacks a concavity. In contrast, the females of A. patriciae sp. nov. and A. shannonae sp. nov. have a broadened, suboval propod (length 1.5 – 1.7 × width) with a very distinct concavity on the palm. Coxa 1 is slightly (females) to weakly (males) widened distally. It is slightly more widened in both the new species, A. patriciae and A. shannonae (especially in females). Coxa 5 is very weakly posterolobate in A. abyssorum but distinctly more in A. patriciae and A. shannonae. The distal bevel of the posterior margin of the pereopod 7 basis is straighter in A. patriciae and A. shannonae, and in the former species, the basis is more subrectangular, with the front margin straight. The uropod 3 inner ramus extends to about 70 % of the length of the outer ramus article 2; in A. shannonae, it is much shorter, reaching about 20 – 25 % of the length of the outer ramus article 2 and in A. patriciae, the inner ramus reaches to about 63 % of the length of article 2. Other differences are provided in the key to the species (see p. 68).	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C54407B9E1807024C9FFC6AFDC9.taxon	description	urn: lsid: zoobank. org: act: 267 EAAEE- 5 F 5 C- 4 DAA- 93 F 9 - 014 B 36 F 6 B 0 AB Figs 10 – 17	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C54407B9E1807024C9FFC6AFDC9.taxon	diagnosis	Diagnosis Pereonites 1 – 7 and pleonites 1 – 2 with a slight but distinct dorsoposterior hump on each segment. Lateral cephalic lobe broadly rounded, dorsal and ventral margins slightly dissimilar in shape, dorsal margin strongly convex, ventral margin nearly straight with a very slight concavity. Antennae 1 – 2 of male with calceoli, female without. Epistome level with and scarcely differentiated from upper lip. Maxilla 1 palp distal end weakly convex and with conical apical spines contiguous. Maxilliped inner plate, distal margin shallowly but distinctly concave, with a very weak mediodistal extension; outer plate inner margin very weakly scalloped. Coxa 1 distinctly widened, distal width 1.3 × proximal width or greater. Gnathopod 2 propodus of female broadened, subovate, length 1.7 × width (different in form to narrow male propodus), dactylus large, inserted at the top of distal margin and occupying most of the length (~ 85 %) of the distal margin, forming a distinct, small gap on the palm. Coxa 5 posteroventral lobe narrowly rounded, posterior margin with distinct straight section. Pereopod 7 basis, posteroventral corner shallowly and weakly beveled. Uropod 1 peduncle relatively short, length less than 1.5 × length of outer ramus. Uropod 3 inner ramus extends to ~ 63 % of article 2 of uropod 3 outer ramus. Telson cleft ~ 52 % of length.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C54407B9E1807024C9FFC6AFDC9.taxon	etymology	Etymology The species name is dedicated to Patricia De Broyer, the daughter of the co-author.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C54407B9E1807024C9FFC6AFDC9.taxon	materials_examined	Material examined Holotype NORTHEAST ATLANTIC • ♀ (mature, 10.5 mm, figured, appendages on 3 slides); Porcupine Abyssal Plain; RRS James Cook (2011), station JC 062 - 063; 49 ° 05.3 ′ N, 16 ° 40.0 ′ W; depth 4848 m; gear, baited traps, A-trap B 2; 8 Aug. 2011; NHM UK 2022.6 (see Horton et al. 2020). Allotype NORTHEAST ATLANTIC • 1 ♂ (7.5 mm, figured, appendages on 3 slides); same collection data as for holotype; NHM UK 2022.7. Paratypes NORTHEAST ATLANTIC • 3 ♀♀ (7.0 – 10.8 mm), 2 ♂♂ (5.5 – 7.0 mm); same collection data as for holotype; NHM UK 2022.8 • 3 ♀♀, 2 ♂♂; same collection data as for holotype; CMNC 2022 - 0002 • 3 ♀♀, 3 ♂♂; same collection data as for holotype; RBINS INV. 138.487. Additional material NORTHEAST ATLANTIC • 10 specs (♀♀ & ♂♂); same collection data as for holotype; NHM UK 2022.9 • 20 specs (♀♀ & ♂♂); same collection data as for holotype; CMNC 2022 - 0003 • 20 specs (♀♀ & ♂♂); same collection data as for holotype; RBINS INV. 138.488. NORTHWEST ATLANTIC • 2 ♀♀ (7.5 – 8.5 mm); Mid-Atlantic Ridge area, north of Charlie-Gibbs Fracture Zone; RRS James Cook (2009), station JC 037 - 060; 53 ° 58.46 ′ N, 36 ° 06.12 ′ W; depth 2340 m; gear baited traps; 27 – 30 Aug. 2009; CMNC 2022 - 0004 • 3 ♀♀; same collection data as for preceding; RBINS INV. 138.489.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C54407B9E1807024C9FFC6AFDC9.taxon	description	Description Holotype Mature female, 10.5 mm, NHM UK 2022.6. PEREONITES 1 – 7 AND PLEONITES 1 – 2 (Figs 10 – 11). With a slight but distinct dorsoposterior hump on each segment (note: Fig. 10 is of male, but female is similar). PLEONITE 3 (Fig. 11). With a rounded, posterodorsal elevation slightly overhanging urosomite 1. COXAE 1 – 2 (Fig. 10). Slightly shorter than corresponding pereonites (in lateral view) (note: Fig. 10 is of male, but female is similar). COXAE 3 – 4 (Fig. 10). Slightly longer (~ 1.2 ×) than corresponding pereonites (note: Fig. 10 is of male, but female coxae are slightly deeper). EPIMERON 3 (Fig. 11). Subquadrate, with posterodistal angle very slightly obtuse, posterior margin weakly but regularly convex, ventral margin convex. UROSOMITE 1 (Fig. 11). With a deep, narrow dorsal concavity in front of the strongly projecting, slightly unequally rounded, dorsal boss, slightly overhanging urosomite 2. HEAD (Fig. 11). Slightly longer (1.13 ×) than pereonite 1. LATERAL CEPHALIC LOBE (Fig. 11). Broadly rounded, dorsal and ventral margin not similar in shape, dorsal margin strongly convex, ventral margin nearly straight with a slight concavity. EYE (Fig. 11). Non ommatidial, formed of pigment granules; long, narrow, L-shaped, extending parallel to the front head margin, length about 63 % of the head height (note: eye shape and size are best observed with fresh specimens, as over time in preservation the labile components of the eye pigments can be lost, causing the eyes to become extremely difficult to ascertain- see eye of freshly collected male, Fig. 10). ANTENNA 1 (Fig. 11). Peduncular article 1 dilated (length 1.3 × width), without small dorsal keel projecting distally over article 2; flagellum broken after the sixth article (likely with 9 – 10 articles counted from 6 other females), length 1.5 × peduncle, first article of flagellum callynophorate, densely furnished medially with double row of aesthetascs; accessory flagellum 5 - articulate, first article slightly broader and longer than remaining articles combined, calceoli absent. ANTENNA 2. Slightly longer (less than 1.3 ×) than antenna 1; geniculate between peduncular articles 3 – 4, peduncular articles 4 – 5 lined with anteromedial brush setae; flagellum 12 - articulate, calceoli absent. EPISTOME (Fig. 11). Level with and scarcely differentiated from upper lip, forming long anterior cephalic ridge, weakly concave. UPPER LIP (Fig. 12). Not protruding, with an asymmetrical midventral, angular projection. MANDIBLE (Fig. 12). Incisor strongly convex and widened; left lacinia mobilis curved, with 2 strong apical teeth, right lacking; accessory spine row with 3 strong spines, interspersed with fine setae; molar forming a narrow crest, somewhat falciform, acutely produced on proximal end, setose with mixed ornamentation, distal half or third setiferous, proximal half or two-thirds forming a reduced, ridged triturative surface, hairy process attached proximal to molar; palp attached proximal to molar, article 2 1.65 × length of article 3, with 17 A 2 setae, article 3 falciform, 0.61 × length of article 2, with 1 A 3 - seta, 20 D 3 - pectinate setae and 3 E 3 - setae. LOWER LIP. Outer lobes broad with inner margins strongly setose, distal inner margins excavated; without inner lobes, mandibular lobes narrow, rounded. MAXILLA 1 (Fig. 12). Inner plate with small, distal subtriangular projection surpassing the basal insertion of the 2 subapical plumose setae; outer plate with 11 elongated spine-teeth in 7 / 4 crown arrangement; palp article 2 strongly widened at distal two-thirds, with 10 (left side) or 9 (right side) contiguous conical apical spines, and one apical strong seta on outer corner. MAXILLA 2 (Fig. 13). Outer and inner plates tapering distally, both with strong rows of pectinate medial marginal spines and setae; inner plate much shorter and distinctly narrower than outer plate, with marginal setae on the distal third of the inner margin, distal end of inner plate not reaching the proximal end of setal row of outer plate. MAXILLIPED (Fig. 13). Inner plate subrectangular, extending slightly past the distal end of the inner margin of palp article 1 and reaching about 0.34 × length of outer plate, distal margin shallowly but distinctly concave, with very weak mediodistal extension, not surpassing the level of the weak outer extension, with 3 strongly embedded nodular spines, the two mediodistal marginal nodular spines situated close to each other, the third one located in about the middle of the plate, medial margin strongly setose; outer plate elongated, subovate, length 1.83 × width, reaching the distal end of palp article 2, with two dissimilar apical spines and numerous (12) embedded, medial nodular spines, medial margin very slightly scalloped; palp strongly setose medially, article 4 well developed, about 0.56 × length of article 3, inner margin with 2 – 3 distal setae. GNATHOPOD 1 (Fig. 14). Coxa distinctly widened, distal width 1.3 × proximal width and about 76 % of length, anterior margin concave, anterodorsal corner rounded, posterior margin nearly straight, distal margin strongly convex in anterior half, weakly convex in posterior half, posteroventral corner not narrowly rounded; basis stout, width about one third of the length and similar to propod width, anterior margin with very short setae; ischium subequal to merus, both with posterior margins setose; carpus short, about half the length of the propodus, with produced narrow posterodistal lobe, not guarding the hind margin of propodus; propodus subchelate, subrectangular, slightly narrowing distally, with anterior margin regularly convex, posterior margin slightly concave, with a distinct inflexion at distal two-thirds, palm transverse, microcrenulate, palmar corner with 2 blunt protrusions and defined by 1 medial and 1 lateral spine; dactylus subequal to palm or barely overriding palm corner. GNATHOPOD 2 (Fig. 15). Coxa subrectangular, length 2.2 × width; basis elongated, distal third slightly curved, length 7.3 × width; ischium length 2.7 × width; carpus stout, length 2 × width, about 1.6 × propodus; propodus chelate, subovate, length 1.72 × width, widest subproximally and about 75 % of the carpus width, surface finely setose with distal groups of long pectinate setae, dorsal margin strongly convex, hind margin weakly convex, nearly straight; dactylus large, inserted at the top of the distal margin and occupying most of the length (~ 85 %) of the distal margin, forming a distinct, small gap on the palm. PEREOPOD 3 (Fig. 16). Coxa with anterior margin very slightly convex, posterior margin nearly straight, length 2.3 × width; posterior margins of ischium-merus with clusters of long setae; rest of pereopod as in pereopod 4. PEREOPOD 4 (Fig. 16). Coxa length 1.4 × width, width 0.7 × length, anterior margin strongly convex, posterior margin deeply excavate, with wide subtriangular, posterodistal lobe, ventral margin straight, angle subrectangular with rounded apex, located at distal 70 % of the coxa length; posterior margins of ischium-merus with clusters of long setae; propodus with 4 – 5 short spine groups; dactylus 0.43 × length of propodus. PEREOPOD 5 (Fig. 16). Coxa slightly but distinctly posterolobate, posterior lobe narrowly rounded, irregularly convex, with distal half of posterior margin straight, width slightly exceeding (1.12 ×) length; basis slightly longer (1.1 ×) than wide, regularly narrowing distally from halfway along the posterior margin, with 4 weak serrations, posterodistal lobe extending to distal margin of ischium; merus weakly expanded (width 0.66 × length), longer than carpus and bearing anterior and posterior long setae; carpus with anterior marginal setae; propodus narrow, length equal to merus-carpus, with 4 – 5 anterior marginal short spine groups; dactylus short, length 0.34 × propodus. PEREOPOD 6 (Fig. 16). Basis long, length 1.5 × width, posterior margin with 8 weak serrations, posterodistal lobe not reaching distal margin of ischium; merus slightly expanded (slightly narrower than in P 5) and bearing anterior marginal long setae and few short slender posterior spines; propodus equal in length to merus-carpus, anterior margin with 4 – 5 clusters of short spines; dactylus 0.33 × length of propodus. PEREOPOD 7 (Fig. 16). Coxa subovate, length slightly shorter than width; basis proximal two-thirds subrectangular, anterior margin slightly concave, distal third of posterior margin with a relatively strongly angled bevel, with about 9 weak serrations, posterodistal lobe not extending to distal margin of ischium; merus not expanded (narrower than in P 6), anterior margins of merus-carpus with short spine groups, posterior margin bearing few short slender spines; propodus about equal to merus-carpus; dactylus 0.33 × length of propodus. UROPOD 1 (Fig. 17). Peduncle about 1.45 × length of outer ramus and 1.64 × inner ramus, dorsolateral and dorsomedial margins spinose; inner ramus shorter and more spiniferous than outer ramus; outer ramus medial margin lacking spines. UROPOD 2 (Fig. 17). Peduncle length 1.2 × outer ramus, dorsolateral and dorsomedial margins with 5 and 1 spine respectively; inner ramus slightly shorter than outer ramus, outer ramus with 10 closely spaced slender spines on dorsolateral margin; inner ramus margins with 2 and 3 slender spines. UROPOD 3 (Fig. 17). Peduncle 0.77 × length of biarticulate outer ramus; second article of outer ramus 0.38 × length of article 1; inner ramus extends past distal end of article 1 of outer ramus and reaches 0.63 × length of article 2 of outer ramus, inner margins of rami with long plumose setae and outer margins with a few slender spines. TELSON (Fig. 17). 1.7 × longer than wide, cleft (52 %), lobes tapering distally with 2 – 3 lateral, submarginal spines and 1 distal spine set in middle of lobe tip. GILLS 5 AND 6 (Fig. 16). With 1 long, tubular accessory lobe on gill 5 and 2 lobes on gill 6. GILL 7 (Fig. 16). Present, well developed. BROOD PLATES (Figs 15 – 16). Present on gnathopod 2 and pereopods 3 – 5, long, slender and curved distally, largest on gnathopod 2 and pereopods 3 – 4, smallest on pereopod 5, with long curved brood setae ranging in number from 11 – 24. STOMODEUM. Extending to the 7 th pereonite. Male (Allotype 7.5 mm, NHM UK 2022.7). Similar to female, but differing as follows: BODY (Fig. 10). Smaller and generally less robust. HEAD (Figs 10 – 11). Slightly longer (1.27 ×) than pereonite 1. LATERAL HEAD LOBE (Figs 10 – 11). Narrower distally and dorsal margin not as strongly convex. ANTENNA 1 (Fig. 11). Longer relative to body length than female, peduncle 1 stouter, length very slightly greater than width; callynophore stronger, flagellar articles shorter, with calceoli. ANTENNA 2 (Fig. 11). Longer relative to body length than female, flagellum 14 - articulate, with calceoli. MANDIBLE (Fig. 12). Palp article 2 shorter, length 1.5 × article 3. MAXILLA 1 (Fig. 12). Inner plate, distal projection more acute. MAXILLIPED (Fig. 13). Inner plates, distal margin more deeply excavated. PEREOPODS (Figs 14, 17). Coxae narrower; rest of pereopods slightly more gracile. GNATHOPOD 1 (Fig. 14). Coxa slightly less widened, anteroventral corner more narrowly rounded; basis distinctly narrower than propodus. GNATHOPOD 2 (Fig. 14). Coxa narrower and slightly widened distally; propodus distinctly narrower, length 2.48 × width and about 61 % of carpus width, with straight hind margin, palm without a gap. COXA 4 (Fig. 17). Distinctly narrower, with posterodistal lobe more regularly convex. PEREOPOD 5 (Fig. 17). Merus more strongly expanded (width 0.7 × length). UROPOD 2 (Fig. 17). Distolateral marginal spines of peduncle grouped closely together; inner ramus distinctly shorter than outer; outer ramus distolateral spines much stouter, bluntly rounded and more closely spaced, proximal ones are slender and sharp (see comment, p. 24). UROSOMITE 1 (Fig. 10). Boss slightly more protruding.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C54407B9E1807024C9FFC6AFDC9.taxon	distribution	Distribution Northeast and Central North Atlantic: Porcupine Abyssal Plain (Thurston 1990); Biscay Abyssal Plain? Cape Verde Basin? (Thurston 1990: identifications to be confirmed); Mid-Atlantic Ridge vicinity (Horton et al. 2013) Depth range Bottom records: 2340 m (Horton et al. 2013) to 4849 m (Thurston 1990). Pelagic records: 0 – 20 to 500 – 1000 m above bottom (Thurston 1990, identifications to be confirmed).	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C54407B9E1807024C9FFC6AFDC9.taxon	discussion	Remarks In many subtle ways, the new species Abyssorchomene patriciae sp. nov. appears to be a pseudocryptic species, with a facies very superficially similar to both the north and southwest Atlantic species A. abyssorum (Stebbing, 1888) and the southwest Atlantic-Antarctic new species A. shannonae sp. nov. (this paper). For instance, these three species all possess the slight, but distinct dorsoposterior rounded hump on pereonites 1 – 7 and pleonites 1 – 2, which is unique among Abyssorchomene. As well, the uropod 3 inner ramus extends past the distal end of article 1 of the outer ramus of uropod 3. These characters easily differentiate A. abyssorum, A. patriciae and A. shannonae from the Southern Ocean endemic A. scotianensis (Andres, 1983). In general body shape and form, they are all extremely similar. However, upon critical examination, we have found several detailed morphological characters that differentiate A. patriciae sp. nov. as follows (character of A. abyssorum in brackets). From A. abyssorum, it differs in the shape of the lateral head lobe, with dorsal and ventral margins not similar, dorsal margin strongly convex, ventral margin nearly straight with slight concavity (vs dorsal and ventral margins more similar, dorsal margin weakly convex and ventral margin straighter); coxa 1 is distinctly widened distally and the anterodorsal corner is broadly rounded in the female (vs only very slightly widened and the anterodorsal corner is narrowly rounded in the female); the mature female gnathopod 2 propodus broadened, subovate, length ~ 1.7 × width, dactylus large, inserted at the top of the distal margin and occupying most of the distal margin, with a small palmar gap (vs propodus very slender, similar to male, length ~ 2.5 × width, dactylus tiny, without a palmar gap); the shorter uropod 1 peduncle, which is 1.45 × the length of the outer ramus (vs longer uropod 1 peduncle, which is 1.5 – 1.7 × the outer ramus) and the length of the uropod 3 inner ramus, which reaches to ~ 63 % of article 2 of uropod 3 outer ramus (vs reaching to ~ 70 % of article 2 of outer ramus). The broadened gnathopod 2 propodus of mature females is not found in smaller, immature females and is likely a terminal growth stage character which presents at maturity, when brood plates are fully formed with long brood setae. Immature females possess a gnathopod 2 propodus which approximates the condition found in males. These are slender and lack the palmar concavity. This makes these taxa difficult to separate without mature females; however, we give other characters which, in total, aid in identifying these species without mature females. Several of these small differences are found in the mouthparts, especially maxilla 2 and the maxilliped and these are outlined in the descriptive text for this species. The characters that differentiate A. patriciae sp. nov. and A. shannonae sp. nov. are outlined in the Remarks section under A. shannonae (p. 67) and in the key (p. 68).	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440469E0B07424FAEFC4AFA4F.taxon	description	Figs 18 – 25	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440469E0B07424FAEFC4AFA4F.taxon	diagnosis	New diagnosis Pereonites 1 – 7 and pleonites 1 – 2 smooth, without any dorsoposterior humps. Lateral cephalic lobe broadly rounded, dorsal and ventral margins regularly and nearly equally convex. Antennae 1 – 2 of male with calceoli, female without. Epistome weakly but distinctly protruding in front of upper lip (or level with upper lip). Maxilla 1 palp distal end strongly convex, with conical distal spines not contiguous. Maxilliped inner plate, distal margin regularly beveled, very slightly concave, with mediodistal extension slightly surpassing the level of the outer corner; outer plate inner margin weakly scalloped. Coxa 1 distinctly widened, distal width ~ 1.4 × proximal width. Gnathopod 2 propodus of female slender, length ~ 3 × width (similar in form to male), dactylus small, inserted in the middle of the distal margin, lacking a palm concavity. Coxa 5 slightly but distinctly posterolobate, posterior lobe irregularly convex, with distal half of posterior margin nearly straight. Pereopod 7 basis, distal third of posterior margin with a straight bevel. Uropod 1 peduncle length ~ 1.6 × length of outer ramus. Uropod 3 inner ramus barely reaches (or very slightly exceeds) distal end of article 1 of uropod 3 outer ramus. Telson cleft ~ 50 % in female, more deeply cleft (up to 60 %) in male.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440469E0B07424FAEFC4AFA4F.taxon	materials_examined	Material examined Paratypes SCOTIA SEA • 1 ♀ (9.0 mm), 1 juvenile (2.7 mm); FFS Walther Herwig, station 210, Hol 239; 63 ° 22 ′ S, 054 ° 10 ′ W; depth 0 – 223 m (bottom depth 235 m); gear, Rectangular Midwater Trawl (RMT) 1 + 8; 13 Jan. 1978; A. Baker and F. Nast leg.; ZMH K 32 401. Additional material WESTERN WEDDELL SEA • 1 ♀ (mature, 12 mm, figured, appendages on 2 slides); off East Peninsula, Larsen B; RV Polarstern ANT XXIII- 8 (IPY-CAML), station PS 69 - 706 - 7; 65 ° 26.57 ′ S, 061 ° 26.82 ′ W; depth 828 m; gear, fish traps; 15 Jan. 2007; C. d’Udekem d’Acoz and H. Robert leg.; CMNC 2022 - 0005 • 1 ♀ (9.5 mm, head figured); same collection data as for preceding; CMNC 2022 - 0006 • ♂ (12.4 mm, figured, appendages on 2 slides); same collection data as for preceding; CMNC 2022 - 0007 • 9 ♂♂ (8 – 11 mm); same collection data as for preceding; RBINS INV. 138.498 • 2 ♂♂, 2 ♀♀, 2 juveniles; same collection data as for preceding; RBINS INV. 138.490 • 1 ♂, 1 ♀; same collection data as for preceding; RBINS INV. 138.493 • 51 specs (♀ up to 11.4 mm); same collection data as for preceding; RBINS INV. 138.494 • 50 specs (♀ up to 11.0 mm); same collection data as for preceding; CMNC 2022 - 0008. ROSS SEA • 2 ♂♂ (8.6 mm, 5.5 mm), 2 ♀♀ (5.8 mm, 5.5 mm); Ross Ice Shelf, station J 9; 82 ° 22 ′ 30 ″ S, 168 ° 37 ′ 33 ″ E; depth 600 m (under ice 415 m thick); gear, baited traps; 7 – 29 Dec. 1977; T. DeLaca and W. L. Stockton leg.; RBINS INV. 138.495. See Stockton & DeLaca (1982). SOUTHERN OCEAN • 3 ♂♂ (10 – 13.1 mm); Oates Coast, off Oates Land; RV Ob, 3 rd Soviet Antarctic Expedition. (SAE 3), station 337; 69 ° 48 ′ S, 161 ° 49 ′ E; depth 1040 m; 10 Feb. 1958; A. P. Andriashev (Zoological Institute Russian Academy of Sciences, St. Petersburg). AMUNDSEN SEA • 1 ♀ (10 mm, with 13 advanced stage embryos), 1 ♀? (5.7 mm), ♂ (5.8 mm); RRS James Clark Ross, JR 179, BIOPEARL II, station BIO 5 - EBS- 2 A; 73 ° 52 ' 55 " S, 106 ° 18 ' 33 " W; depth 1113 m; gear, epibenthic sledge; 9 Mar. 2008; K. Linse (British Antarctic Survey, Cambridge).	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440469E0B07424FAEFC4AFA4F.taxon	description	Description Based on female (mature), 12 mm (CMNC 2022 - 0005); paratype female, 9 mm, (not illustrated, ZMH K 32 401) and on remaining material described by Andres (1983). PEREONITES 1 – 7 AND PLEONITES 1 – 2 (Fig. 18). Body smooth, without dorsoposterior hump on each segment. PLEONITE 3 (Figs 18 – 19). With a distinct, rounded posterodorsal elevation slightly overhanging urosomite 1. COXAE 1 – 2 (Figs 18 – 19). Subequal to slightly longer (1.1 ×) than corresponding pereonites. COXAE 3 – 4 (Fig. 18). Slightly longer (1.2 ×) than corresponding pereonites. EPIMERON 3 (Figs 18 – 19). Subquadrate, with posterior margin weakly convex, posteroventral corner broadly rounded, with angle slightly obtuse, ventral margin regularly convex. UROSOMITE 1 (Fig. 19). With a deep, dorsal concavity in front of the strongly, regularly rounded upright dorsal boss, convex on posterior margin, and slightly overhanging urosomite 2. HEAD (Fig. 19). About equal in length to pereonite 1. LATERAL CEPHALIC LOBE (Fig. 19). Broadly rounded, dorsal and ventral margins regularly and nearly equally convex. EYE (Fig. 19). Non ommatidial, formed of pigment granules; large, crescent-shaped or L-shaped, parallel to front head margin, length about 70 % of the head height (note: see p. 26, 34 for comments on evaluating eye size / shape). ANTENNA 1 (Fig. 19). Peduncular article 1 dilated (length 1.2 × width), without anterodistal lobe; flagellum article 1 about half length of peduncular article 1, callynophorate, densely furnished medially with double row of aesthetascs; accessory flagellum 5 - articulate, first article long, about equal to the remaining articles combined; flagellum 13 - articulate, calceoli absent. ANTENNA 2 (Fig. 19). Slightly longer (1.2 ×) than antenna 1; geniculate between peduncular articles 3 – 4, peduncular articles 4 – 5 lined with anteromedial brush setae, peduncular article 5 short, length 0.66 × article 4; flagellum 18 - articulate, calceoli absent. EPISTOME (Fig. 19). Level with or very slightly protruding in front of weakly rounded upper lip, forming straight anterior margin and cephalic ridge, separated from upper lip by a small slit. MANDIBLE (Fig. 20). Incisor strongly convex, slightly widened; left lacinia mobilis curved, with 2 strong apical teeth and 1 subapical tooth, right lacking; accessory spine row with 3 strong spines, interspersed with fine setae; molar forming a narrow crest, somewhat falciform, acutely produced on proximal end, setose with mixed ornamentation, distal half or third setiferous, proximal half or two-thirds forming a reduced, ridged triturative surface, hairy process located proximal to molar; palp attached proximal to molar, article 2 1.8 × length of article 3, with 24 – 25 A 2 - pectinate setae, article 3 weakly falciform, 0.55 × length of article 2, with 3 A 3 - seta, 26 D 3 - pectinate setae and 2 E 3 - setae. LOWER LIP (Fig. 20). Outer lobes broad with inner margins strongly setose, distal margins excavate, without inner lobes, mandibular lobes narrow. MAXILLA 1 (Fig. 21). Inner plate with short, rounded, apical projection slightly surpassing the basal insertion of two (or three) apical plumose setae of unequal size; outer plate with 11 strong spine-teeth in 7 / 4 crown arrangement; palp article 2 slightly widened at distal two-thirds, distal margin strongly convex, with 7 – 9 non-contiguous conical apical spines, and a thin spine on outer corner. MAXILLA 2 (Fig. 21). Outer and inner plates not slender, tapering distally, both with strong rows of pectinate medial marginal spines and setae; inner plate much shorter than outer plate, with marginal setae on the distal third of the inner margin, distal end of inner plate slightly surpassing the proximal end of setal row of outer plate. MAXILLIPED (Fig. 21). Inner plate subrectangular, extending slightly past the distal end of the inner margin of palp article 1 and reaching about one-third length of outer plate, distal margin regularly bevelled, very slightly concave, with mediodistal extension slightly surpassing the level of the outer corner; with 3 embedded nodular spines unequally spaced, the two mediodistal marginal nodular spines situated close to each other with the corner one more protruding, the third one located closer to the outer margin corner, plumose setae inserted along medial margin and inner part of distal margin; outer plate subovate, length 1.66 × width, not reaching distal end of palp article 2, with two dissimilar apical spines and numerous (11) embedded, medial nodular spines, medial margin weakly scalloped; palp 4 - articulate, strongly setose medially, dactylus well developed, about 0.7 × length of article 3, distal inner margin with 2 – 3 short setae. GNATHOPOD 1 (Fig. 22). Coxa distinctly widened, distal width 1.43 × proximal width and about 78 % of length, anterior margin weakly concave, anterodorsal corner broadly rounded, posterior margin nearly straight, distal margin strongly convex in anterior half, slightly convex in posterior half, posteroventral corner not narrowly rounded; basis moderately stout, width about one third of the length and slightly narrower than propodus, anterior margin with numerous long and short setae; ischium subequal to merus, both with posterior margins setose; carpus short, compressed, length about 0.5 × propodus, with narrow, setose posterodistal lobe, not guarding the hind margin of propodus; propodus subchelate, subrectangular, with anterior margin weakly convex, posterior margin nearly straight; palm transverse, very slightly convex, microcrenulate and adorned with small setae, palm corner with 2 blunt protrusions and defined by 1 medial and 1 lateral spine; dactylus subequal to palm or barely overriding palmar corner. GNATHOPOD 2 (Fig. 23). Coxa subrectangular, length 2.4 × width; basis elongated, distal third slightly curved, length 6.8 × width; ischium length 3 × width; carpus about 2 × length of propodus, distoventrally with subtriangular scales; propodus chelate, slender, slightly widened distally, length 3 × width, and much narrower, about 60 % of the carpus width, surface finely setose with distal groups of long pectinate setae, dorsal margin convex, hind margin weakly concave, palm not excavate, with a narrow gap, with a small setal basket on distal third and ending in a tooth-like denticulate projection and a strong subapical seta; dactylus fitting palm, inner margin bearing distally a spiny protuberance fitting to the palm and weakly denticulate projection. PEREOPOD 3 (Fig. 24). Coxa subrectangular, with anterior margin slightly convex, posterior margin slightly concave, ventral margin very slightly convex, length 2.45 × width; posterior margins of ischium-merus with clusters of long setae, rest of pereopod like pereopod 4. PEREOPOD 4 (Fig. 24). Coxa length 1.42 × width, width 0.7 × length, anterior margin convex, posterior margin deeply excavate, with wide subtriangular, posterodistal lobe, corner with subquadrate angle, located at distal 63 % of the coxa length; ventral margin evenly convex; posterior margins of ischiumcarpus with clusters of long setae; propodus with about 7 short spine groups; dactylus 0.4 × length of propodus. PEREOPOD 5 (Fig. 24). Coxa slightly but distinctly posterolobate, posterior lobe irregularly convex, with distal half of posterior margin nearly straight, width 1.14 × length; basis longer (1.2 ×) than wide, slightly narrowing distally, anterior margin nearly straight, with small spines, posterior margin convex, very weakly serrate, posterodistal lobe surpassing distal margin of ischium; merus weakly expanded (width 0.65 × length), longer than carpus and bearing anterior and posterior long setae; carpus with anterior marginal setae; propodus narrow, shorter than merus-carpus, with 6 – 7 anterior marginal short spine groups; dactylus short, 0.36 × length of propodus. PEREOPOD 6 (Fig. 24). Basis long, length 1.45 × width, anterior margin nearly straight, with small spines, posterior margin hardly serrate, slightly narrowing distally, posterodistal lobe not reaching distal margin of ischium; merus very weakly expanded (width 0.48 × length) and bearing anterior marginal long setae and few short slender posterior spines; propodus shorter than length of merus-carpus, anterior margin with 7 – 8 clusters of short spines, dactylus 0.34 × length of propodus. PEREOPOD 7 (Fig. 24). Coxa subovate, rounded behind; basis proximal two-thirds subrectangular, anterior margin slightly concave, with small spines, distal third of posterior margin with a straight bevel, with about 9 weak serrations, posterodistal lobe not extending to distal margin of ischium; merus not expanded (narrower than in P 6), anterior margins of merus-carpus with short spine groups, posterior margin bearing few short slender spines; propodus shorter than merus-carpus, dactylus broken. UROPOD 1 (Fig. 25). Peduncle about 1.57 × length of outer ramus and 1.73 × inner ramus, dorsolateral and dorsomedial margins spinose; inner ramus shorter and more spiniferous than outer ramus; outer ramus medial margin lacking spines. UROPOD 2 (Fig. 25). Peduncle about 1.2 × length of outer ramus, dorsolateral and dorsomedial margins each with 4 spines; inner ramus slightly shorter than outer ramus, length 0.92 ×, with 2 dorsolateral and 6 dorsomedial marginal spines; outer ramus with 7 closely spaced slender spines on dorsolateral margin, dorsomedial margin lacking spines. UROPOD 3 (Fig. 25). Peduncle 0.94 × length of biarticulate outer ramus; second article of outer ramus 0.4 × length of article 1; inner ramus barely reaching or very slightly extends past distal end of article 1 of outer ramus, inner margins of rami with long plumose setae and outer margins with a few slender spines. TELSON (Fig. 25). Length subequal to uropod 3 peduncle, 1.5 × longer than wide, cleft (50 %), lobes tapering distally with 3 – 4 submarginal spines and 1 distal spine set in middle of lobe tip. GILLS 5 – 6 (Fig. 24). With 1 long, tubular accessory lobe on gill 5 and 2 lobes on gill 6, both inserted basally. GILL 7 (Fig. 24). Present, small. BROOD PLATES (Figs 23 – 24). Present on gnathopod 2 and pereopods 3 – 5, long, slender and curved distally, largest on gnathopod 2 and pereopods 3 – 4, smallest on pereopod 5, with long curved brood setae ranging in number from ~ 10 – 20. STOMODEUM. Extending to the 7 th pereonite. Male (based on: Andres (1983), ANT XXIII- 8, station 706 and SAE 3 material) Similar to female, but differing as follows: BODY (Fig. 18). Larger but slightly less robust. LATERAL HEAD LOBE (Fig. 19). Slightly narrower distally, subtriangular, ventral margin less convex. EYE (Figs 18 – 19). More strongly developed, extending to 66 – 80 % of the head height. ANTENNA 1 (Figs 18 – 19). Callynophore much stronger, subequal in length to peduncular article 1, flagellum 12 – 17 - articulate, articles broader, calceoli present (callynophore size is related to maturity of male, terminal males have the largest callynophore and greater number of flagellar articles). ANTENNA 2 (Fig. 18). Peduncular articles 4 – 5 slightly broader; flagellum 15 – 23 - articulate, with calceoli. MANDIBLE. Palp article 3 proportionally longer, length 0.65 × article 2. MAXILLA 1 (Fig. 21). Inner plate, distal projection subacute; palp article 2 strongly widened at distal twothirds, with (according to size) 5 – 12 non-contiguous, conical apical spines. GNATHOPOD 1. Coxa slightly less widened distally than in female, length 1.34 × width, anteroventral corner more narrowly rounded, posterior margin slightly concave; basis, anterior margin with scattered short setae. GNATHOPOD 2 (Fig. 22). Propodus similar to female, except anterodistally narrower and merging smoothly with dactyl insertion on dorsal margin. COXA 4 (Fig. 24). Distinctly narrower than in female, length about 1.76 × width, posterior excavation shallower, posterior lobe smaller with subquadrate angle located at about 60 % of the length. PEREOPOD 5. Merus slightly more expanded. UROPOD 2 (Fig. 25). Inner ramus distinctly shorter than outer; outer ramus with 15 lateral marginal spines of differing morphology, distolateral spines stouter, bluntly rounded and more closely spaced than proximal ones, which are thin and acute (number of spines is size related, but males of equal size to females have greater number of spines and always possess the two different types of spines, see p. 24). UROPOD 3 (Fig. 25). Inner ramus slightly longer than peduncle; second article of outer ramus about 0.33 – 0.5 × the length of article 1. UROSOMITE 1 (Figs 18 – 19). Boss strong, anterodorsal and posterior margins straighter, slightly more pointed and slightly more projecting backward. TELSON. Slightly narrower and longer, length 1.75 × width; cleft slightly deeper, about 55 – 60 % of its length. Ontogenic variations Andres (1983) collected a very large male (16 mm) and noticed on maxilla 1 that the width of palp article 2 increases in size as well as the number (as usual) of apical spines (from 5 in the holotype male, 9.5 mm, to 8 in the 13 mm female and 12 in the 16 mm male; see Andres’ 1983: fig. 10). On the maxilliped outer lobe of the 16 mm male, he noted the presence of 4 apical stout spines instead of the usual 2 stout spines, as well as the presence of setae on the inner margin of the dactylus in the palp of larger specimens. As well, he remarked on the stronger development of the gnathopod 2 palm and dactylus spines and setae in the largest specimens. He also showed that the length of the second article of uropod 3 outer ramus reaches 0.34 × the length of article 1 in the largest male, instead of about 0.5 × the length in the smaller, 9.5 mm holotype (see Andres’ 1983: fig. 12).	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440469E0B07424FAEFC4AFA4F.taxon	distribution	Distribution Southern Ocean: Scotia Sea (Andres 1983); Wilhelm II coast (Schellenberg 1926); Weddell Sea (De Broyer et al. 1999, 2001, 2004, 2006, 2007; d’Udekem d’Acoz & Robert 2008; d’Udekem d’Acoz & Havermans 2012); Amundsen Sea (this paper); Ross Sea (this paper); off Oates Land (this paper). Depth range Bottom records: possibly 60 m? (Wakabara et al. 1990), depth 385 m (Schellenberg 1926) to 3070 m (De Broyer et al. 2004). Pelagic records: possibly 0 to 430 m above bottom (Andres (1983). See remark (p. 24) on pelagic occurrence under A. abyssorum.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440469E0B07424FAEFC4AFA4F.taxon	discussion	Remarks As discussed by Andres (1983), the juvenile Antarctic specimens identified as Orchomenopsis chilensis f. abyssorum by Schellenberg (1926) may be attributed to Abyssorchomene scotianensis. The peculiar shape of the maxilla 1 palp article 2 figured by Barnard (1932) (Fig. 28) also indicates that this material may belong to A. scotianensis, but the presence of the “ large yellowish brown pear-shaped ” eyes should be confirmed first. Andres (1983) also described “ extended pear-shaped ” (“ gestreckt birnenförmige Augen ”) and Nicholls (1938) (Fig. 15) illustrated a “ large, faded brown ”, typically pear-shaped eye, although he recognized that his material had undergone a considerable degree of maceration. We never noticed pearshaped eyes among the abundant material we identified. Indeed, specimens we examined showed the typical, large “ L-shaped eyes ”, with larger males having larger eyes (see Figs 18 – 19). As previously noted (p. 34), eye shape and size are best recognized in freshly collected specimens. Over long periods of time in alcohol preservation, colour pigments fade and are lost, causing the eyes to become extremely difficult to ascertain. This problem may be a contributing factor in the discrepancies seen in eye morphology described by the authors above. Concerning male body size in this species, it is interesting to note that this is the only species in the A. abyssorum complex where males can reach or exceed female body length; in the other species terminal males are always much smaller than females (Andres 1983; Duffy et al. 2013). Our material examined also confirm this anomaly in size difference. Possible reasons for this size discrepancy will require future investigation. The Southern Ocean endemic A. scotianensis can be easily distinguished from the three other species of the A. abyssorum complex by the following combination of characters: the absence of small dorsal humps on pereonites 1 – 7 and pleonites 1 – 2; the short uropod 3 inner ramus, which just reaches (or very slightly exceeds) the distal end of article 1 of uropod 3 outer ramus; the epistome usually slightly protruding in front of the upper lip; the maxilla 1 palp, with distal margin strongly convex and distal spines not-contiguous and by the nearly straight (female) distal margin of maxilliped inner plate. Further, A. scotianensis is also distinguished from A. shannonae sp. nov. and A. patriciae sp. nov. by the absence of an excavated palm in the gnathopod 2 propodus of mature females.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440559E7D07744B2BFDEEF85F.taxon	description	urn: lsid: zoobank. org: act: EEBF 5622 - BB 6 E- 4 CA 5 - 9767 - 4 CFE 71 A 4 ED 9 F Figs 26 – 34	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440559E7D07744B2BFDEEF85F.taxon	diagnosis	Diagnosis Pereonites 1 – 7 and pleonites 1 – 2 with a weak but distinct dorsoposterior hump on each segment. Lateral cephalic lobe broadly rounded, dorsal and ventral margins nearly equally convex. Antennae 1 – 2 of male with calceoli, female without. Epistome level with the upper lip. Maxilla 1 palp, distal end weakly convex with distal conical spines contiguous. Maxilliped inner plate, distal margin nearly straight, strongly beveled, with a very slight concavity on outer half, with mediodistal extension surpassing outer corner; outer plate with strongly scalloped inner margin. Coxa 1 strongly widened distally, ~ 1.5 – 1.7 × proximal width. Gnathopod 2 propodus of female broad, anterodistal margin slightly expanded and protruding, length ~ 1.5 × width, (different in form to narrow male propod), dactylus very small, inserted on the posterodistal one-third of the distal margin, palm with a distinct concavity. Coxa 5 distinctly posterolobate, posteroventral lobe broadly rounded, posterior margin evenly rounded. Pereopod 7 basis with anterior margin slightly concave, distal half of posterior margin with a steep, strong bevel. Uropod 1 peduncle long, about 1.6 × length of outer ramus. Uropod 3 inner ramus extends past distal end of article 1 and reaches 20 – 25 % length of article 2 of outer ramus. Telson cleft 55 % of length, deeper in males.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440559E7D07744B2BFDEEF85F.taxon	etymology	Etymology The species name is dedicated to Shannon Hendrycks, the wife of the first author for her continued enthusiasm and support over the many years of this and other amphipod studies.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440559E7D07744B2BFDEEF85F.taxon	materials_examined	Material examined Holotype EASTERN WEDDELL SEA • ♀ (12 mm, mature, figured, appendages on 7 slides); RV Polarstern ANT XXII- 3 (ANDEEP III), station PS 67 - 78 - 1; 71 ° 9.91 ′ S, 014 ° 4.80 ′ W; depth 2194 m; gear, baited traps; 21 Feb. 2005; C. De Broyer and B. Danis leg.; ZMH K- 61209. Allotype EASTERN WEDDELL SEA • ♂ (7 mm, figured, appendages on 6 slides); same collection data as for holotype; ZMH K- 61210. Paratypes EASTERN WEDDELL SEA • 2 ♀♀ (8.4 mm, with dissected Gn 1 – 2, 9.5 mm); same collection data as for holotype; RBINS INV. 138.491 • 2 ♀♀ (8.4 mm, 11.8 mm); same collection data as for holotype; CMNC 2022 - 0009 • 2 ♀♀ (mature, 10 mm), 4 ♀♀ (immature, 7.5 mm), 4 ♂♂ (~ 6 mm); same collection data as for holotype; CMNC 2022 - 0010. Additional material EASTERN WEDDELL SEA • 6 specs (6 – 8 mm); RV Polarstern ANT XXII- 3 (ANDEEP III), station PS 67 - 80 - 1; 70 ° 40.78 ′ S, 014 ° 41.24 ′ W; depth 2928 m; gear, baited traps; 22 Feb. 2005; C. De Broyer and B. Danis leg.; RBINS INV. 138.492 • 2 ♀♀ (immature, 8.0 mm, 9.0 mm), 2 ♂♂ (5.6 mm, 7.0 mm); RV Polarstern ANT XXII- 3 (ANDEEP III), station PS 67 - 81 - 1; 70 ° 31.63 ′ S, 014 ° 35.00 ′ W; depth 4412 m; gear, baited traps; 23 Feb. 2005; C. De Broyer and B. Danis; RBINS INV. 138.496. NORTHWEST WEDDELL SEA • 1 ♀ (12.4 mm, mature); Powell Basin; RV Polarstern ANT XXII- 3 (ANDEEP III), station PS 67 - 142 AT; 62 ° 12.40 ′ S, 049 ° 31.67 ′ W; depth 3411 m; gear, baited traps; 18 Mar. 2005; C. De Broyer and B. Danis leg.; RBINS INV. 138.497. SCOTIA SEA • 1 ♀ (12 mm, mature); US Antarctic Research Program, Eltanin 9, station 696; 56 ° 53 ′ S – 56 ° 59 ′ S, 037 ° 27 ′ W – 037 ° 17 ′ W; depth 3001 m; gear, Isaac-Kid Midwater Trawl; 28 Aug. 1963; Smithsonian Oceanographic Sorting Centre, Washington, D. C. SOUTHWEST ATLANTIC • 2 ♀♀ (7 and 8 mm, immature), 1 ♂ (6 mm); Argentine Basin; RV Meteor, DIVA 3 M 79 / 1 expedition, station 531; 35 ° 56.49 ′ S, 048 ° 53.85 ′ W; depth 4586 m; gear, baited traps; 15 Jul. 2009; E. Hendrycks leg.; ZMH K- 61211.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440559E7D07744B2BFDEEF85F.taxon	description	Description Holotype Mature female, 12 mm, ZMH K- 61209. PEREONITES 1 – 7 AND PLEONITES 1 – 2 (Fig. 26). With a slight but distinct dorsoposterior hump on each segment. PLEONITE 3 (Fig. 26). With a rounded, posterodorsal elevation slightly overhanging urosomite 1. COXAE 1 – 2 (Fig. 26). Slightly shorter to nearly subequal to corresponding pereonites (in lateral view). COXAE 3 – 4 (Fig. 26). Subequal to slightly longer (1.15 ×) than corresponding pereonites. EPIMERON 3 (Fig. 26). Subquadrate, with posterodistal angle narrowly rounded and slightly obtuse, posterior margin very weakly convex, nearly straight, ventral margin convex. UROSOMITE 1 (Fig. 26). With a deep, broadly rounded dorsal concavity in front of the strong, regularly rounded, dorsal boss, slightly overhanging urosomite 2. LATERAL CEPHALIC LOBE (Fig. 26). Broadly rounded, dorsal and ventral margin nearly equally convex. EYE (Fig. 26). Non ommatidial, formed of pigment granules; long, relatively narrow, crescent shaped; extending parallel to the front head margin, length about two-thirds of the head height. ANTENNA 1 (Fig. 26). Peduncular article 1 dilated, length 1.3 × width; flagellum 13 - articulate, length 1.5 × peduncle, first article of flagellum callynophorate, densely furnished with double row of aesthetascs medially; accessory flagellum 5 - articulate, first article wider and longer than remaining articles combined; calceoli absent. ANTENNA 2 (Fig. 26). Slightly longer (less than 1.3 ×) than antenna 1; geniculate between peduncular articles 3 – 4, peduncular articles 4 – 5 lined with anteromedial brush setae; flagellum 16 - articulate, calceoli absent. EPISTOME (Fig. 26). Level with the slightly rounded upper lip, from which it is separated by a minute slit; forming long anterior cephalic ridge, weakly concave upward. UPPER LIP (Fig. 26). Anterior margin weakly convex, not protruding; midventral margin with a small, angular projection. MANDIBLE (Fig. 29). Incisor smoothly convex and slightly widened; left lacinia mobilis curved, with 2 strong and 1 weak apical teeth, right lacking; accessory spine row with 3 strong spines, interspersed with fine setae; molar forming a narrow crest, somewhat falciform, acutely produced on proximal end, setose with mixed ornamentation, distal half or third setiferous, proximal half or two-thirds forming a reduced, narrow, triturative surface, hairy process attached proximal to molar; palp attached proximal to molar, article 2 1.56 × length of article 3, with 27 A 2 setae, article 3 falciform, 0.63 × length of article 2, with 1 A 3 - seta, 22 D 3 - pectinate setae and 3 E 3 setae. LOWER LIP (Fig. 28). Outer lobes broad, slightly truncated medially and strongly setose, without inner lobes, mandibular lobes narrow. MAXILLA 1 (Fig. 28). Inner plate ovate, with small blunt distal projection surpassing the basal insertion of the 2 plumose apical setae; outer plate with 11 elongated spine-teeth in 7 / 4 crown arrangement; palp article 2 slightly widened at distal two-thirds, with 10 (left side) or 9 (right side) contiguous (or nearly contiguous) conical apical spines. MAXILLA 2 (Fig. 28). Outer and inner plates strongly tapering distally, both with strong rows of pectinate medial marginal spines and setae; inner plate much shorter than outer plate, with marginal setae on the distal half of the inner margin; apex of inner plate slightly surpassing the proximal end of setal row of outer plate. MAXILLIPED (Fig. 30). Inner plate short, subrectangular, just reaching the distal end of the inner margin of palp article 1 and reaching about 0.3 × length of outer plate, distal margin not excavate, very weakly concave on outer half and sloped, with weak medio-distal extension, with 3 equally spaced, strongly embedded nodular spines, medial margin strongly setose; outer plate well developed, subovate, length 1.58 × width, not reaching inner distal end of palp article 2, with two dissimilar apical spines and numerous (10 – 11) embedded, medial nodular spines, medial margin distinctly scalloped; palp strongly setose medially, article 4 well developed, about half the length of article 3, with 6 apically plumose setae on distal inner margin. GNATHOPOD 1 (Fig. 31). Coxa distinctly widened, distal width 1.53 × proximal width and about 80 % of length, anterior margin slightly concave, anterodorsal corner broadly rounded, posterior margin slightly sinuous, the distal half weakly concave, slightly convex in posterior half, posteroventral corner nearly right angled, narrowly rounded; basis stout, not expanded, width one-third of the length, slightly narrower than propod, anterior margin with long setae; ischium subequal to merus; carpus short, about half the length of the propodus, with produced narrow posterodistal lobe, not guarding the hind margin of propodus; propodus subchelate, subrectangular, with anterior margin regularly convex, posterior margin distinctly concave, with inflexion point at distal two-thirds, palm transverse, microcrenulate, palm corner with 2 blunt protrusions and defined by 1 medial and 1 lateral spine; dactylus subequal to palm or barely overriding palm corner. GNATHOPOD 2 (Fig. 31). Carpus stout, length 2 × propodus; propodus chelate, suboval, anterodistal margin broadly expanded and slightly protruding, surface finely setose with distal groups of long pectinate setae, broad, length 1.48 × width, slightly narrower (about 90 %) than carpus, hind margin weakly but distinctly convex; dactylus very small, inserted on the posterodistal one-third of distal margin, forming a distinct, curved cavity with the slightly excavate palm. PEREOPOD 3 (Fig. 32). Coxa with anterior margin slightly convex, posterior margin slightly concave, length 2.3 × width; rest of pereopod like pereopod 4. PEREOPOD 4 (Fig. 32). Coxa with posterodistal lobe broadly rounded distally, angle subquadrate, located slightly more distally (55 %) than half of the coxa length; posterior margins of ischium-merus with clusters of long setae; propodus with 6 short spine groups; dactylus ~ 0.4 × length of propodus. PEREOPOD 5 (Fig. 32). Coxa distinctly posterolobate, posterior lobe broad and regularly convex, coxa width slightly greater than length; basis length 1.13 × width, posterior margin with small serrations and setules, posterodistal lobe extending to distal margin of ischium; merus slightly expanded (0.63 × length), longer than carpus and bearing anterior and posterior setae; carpus with anterior marginal setae; propodus narrow, length equal to merus-carpus. PEREOPOD 6 (Fig. 32). Coxa with posterodistal lobe broadly rounded; basis length 1.54 × width, posterior margin with 3 – 4 weak serrations, posterodistal lobe not reaching distal margin of ischium; merus slightly expanded (narrower than in P 5) and bearing anterior long setae and few short slender posterior spines only; propodus slightly shorter than merus-carpus, with 6 – 7 clusters of short spines; dactylus 0.3 × length of propodus. PEREOPOD 7 (Fig. 32). Coxa small, subovate; basis with anterior margin slightly concave, distal half of posterior margin strongly beveled, nearly straight, with very weak concavity and 9 weak serrations, posterodistal lobe not extending to distal margin of ischium; merus not expanded (narrower than in P 6), anterior margins of merus-carpus with short spine groups, posterior margin bearing few short slender spines; propodus slightly shorter than merus-carpus; dactylus 0.3 × length of propodus. UROPOD 1 (Fig. 33). Peduncle long, about 1.6 × length of outer ramus and 1.74 × length of inner ramus, dorsolateral and dorsomedial margins spinose; inner ramus slightly shorter than outer, margins of rami with slender spines except medial margin of outer ramus, which lacks spines. UROPOD 2 (Fig. 33). Peduncle about 1.2 × length of outer ramus, dorsolateral and dorsomedial margins with 4 and 3 spines respectively; inner ramus very slightly shorter than outer ramus; outer ramus with closely spaced slender spines on dorsolateral margin; inner ramus margins with slender spines. UROPOD 3 (Fig. 33). Peduncle long, 0.8 × length of biarticulated outer ramus; second article of outer ramus 0.46 × length of article 1; inner ramus extends past distal end of article 1 and reaches 20 – 25 % of article 2 of outer ramus; inner margins of rami with long plumose setae and slender spines. TELSON (Fig. 33). 1.6 × longer than wide, relatively deeply cleft (55 %), lobes tapering distally with 4 lateral, submarginal spines and 1 distal spine. GILLS 5 – 6 (Fig. 32). With 1 long tubular accessory lobe on gill 5 and 2 on gill 6. GILL 7 (Fig. 32). Present, well developed. BROOD PLATES (Fig. 32). On gnathopod 2 and pereopods 3 – 5, long, slender and curved distally, largest on gnathopod 2 and pereopods 3 – 4, with long curved brood setae, 20 setae on pereopod 4 plate and 12 on pereopod 5. STOMODEUM (Fig. 26). Extending to the 7 th pereonite. Male (Allotype 7 mm, ZMH K- 61210). Similar to female, but differing as follows: BODY. Smaller than female, and slightly less robust. LATERAL HEAD LOBE. Slightly narrower. ANTENNA 1 (Fig. 27). Peduncular article 1 stouter, more compact; callynophore stronger, flagellum 8 - articulate, articles shorter, with calceoli. ANTENNA 2 (Fig. 27). Flagellum 12 - articulate with calceoli. MAXILLA 1 (Fig. 28). Palp with 7 distal, conical spines; inner plate, distal projection acute. MAXILLIPED (Fig. 30). Inner plate, distal margin slightly more excavate. PEREOPODS (Fig. 34). Slightly more slender. GNATHOPOD 1 (Fig. 34). Coxa more strongly widened, distal width about 1.7 × proximal width; basis distinctly narrower than propodus, anterior margin lacking long setae. GNATHOPOD 2 (Fig. 34). Coxa slightly narrower and distally widening; propodus slender, length 2.5 × width, about ⅔ of carpus width, slightly expanded anteriorly, with straight hind margin, palm lacking concavity. COXA 3 (Fig. 34). Slightly narrower and widening distally. COXA 4 (Fig. 34). Slightly narrower, ventral margin more evenly convex and posteroventral lobe slightly smaller. COXA 5. Slightly more posterolobate. UROPOD 2 (Fig. 33). Peduncle shorter, about 1.13 × length of outer ramus, distolateral marginal spines of peduncle grouped at distal end; inner ramus distinctly shorter than outer; outer ramus distolateral spines stouter, bluntly rounded and more closely spaced distally, proximal spine acute (see p. 24). UROPOD 3 (Fig. 33). Peduncle shorter, 0.68 × length of biarticulated outer ramus. TELSON (Fig. 33). Cleft deeper (60 %) than female. UROSOMITE 1 (Fig. 26). Dorsal boss more unevenly rounded and slightly more protruding upward. EPIMERON 3 (Fig. 26). Posteroventral corner slightly more subquadrate.	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440559E7D07744B2BFDEEF85F.taxon	distribution	Distribution Southern Ocean: Eastern Weddell Sea (De Broyer et al. 2006); Northwestern Weddell Sea: Powell Basin (De Broyer et al. 2006); Scotia Sea (this paper). Southwest Atlantic: Argentine Abyssal Basin (this paper). Depth range Bottom records: 2194 m (De Broyer et al. 2006) to 4586 m (this paper). Pelagic records: 3001 m (this paper).	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
05062C5440559E7D07744B2BFDEEF85F.taxon	discussion	Remarks Abyssorchomene shannonae sp. nov. is easily differentiated from the smooth bodied Antarctic species A. scotianensis (Andres, 1983) in possessing a slight, but distinct dorsoposterior rounded hump on pereonites 1 – 7 and pleonites 1 – 2. The new species also differs from A. scotianensis by the very steeply angled, truncate bevel of the basis of pereopod 7 (vs weakly angled bevel) and the uropod 3 inner ramus length, which greatly exceeds the distal end of article 1 of the outer ramus (vs just reaching the distal end). Abyssorchomene shannonae sp. nov. is superficially very similar to A. abyssorum and A. patriciae sp. nov., as these species also possess the dorsoposterior hump on the pereonites and pleonites. However, A. shannonae differs from both these species in many characters. From A. abyssorum, it differs in the much greater distally widened coxa 1 (1.4 – 1.7 × proximal width vs 1.2 ×); the (mature) female gnathopod 2 propodus which is broad, with a palm concavity (length less than 1.5 × width vs narrow, ~ 2.4 × width and lacking concavity); the coxa 5 posteroventral lobe which is broadly rounded (vs narrowly rounded); the very strongly, steeply angled truncated bevel of the basis of pereopod 7 (vs weakly angled bevel) and the shorter uropod 3 inner ramus, which extends to about 20 – 25 % of the length of article 2 of the outer ramus (vs extends to 70 % of the length of article 2 of the outer ramus). Lastly, from A. patriciae sp. nov. it differs in the shape of the lateral head lobe, with dorsal and ventral margins nearly similar (vs dorsal and ventral margins not similar, dorsal margin strongly convex, ventral margin nearly straight); the female gnathopod 2 propodus with anterodistal margin broadly expanded and protruding, dactylus tiny, inserted near the bottom of the distal margin (vs anterodistal margin not expanded and protruding, dactylus large, inserted at the top of the distal margin); the coxa 5 posteroventral lobe which is broadly and evenly rounded (vs narrowly rounded, posterior margin straight posterodistally); the longer uropod 1 peduncle, which is 1.6 × the length of the outer ramus (vs 1.45 ×) and the length of the uropod 3 inner ramus, which reaches to 20 – 25 % of article 2 of uropod 3 outer ramus (vs reaching to ~ 63 % of article 2 of outer ramus).	en	Hendrycks, Ed A., Broyer, Claude De (2022): New deep-sea Atlantic and Antarctic species of Abyssorchomene De Broyer, 1984 (Amphipoda, Lysianassoidea, Uristidae) with a redescription of A. abyssorum (Stebbing, 1888). European Journal of Taxonomy 825: 1-76, DOI: 10.5852/ejt.2022.825.1829, URL: http://dx.doi.org/10.5852/ejt.2022.825.1829
