Latigammaropsis savioi, Guedes-Silva & Souza-Filho & Tavares, 2025

Guedes-Silva, Elkênita, Souza-Filho, Jesser F. & Tavares, Marcos, 2025, The Amphipoda of the remote oceanic archipelago Trindade and Martin Vaz (Brazil). II. Five new species of shallow-water aorid and photid amphipods (Senticaudata: Corophiida), Zootaxa 5659 (4), pp. 451-482 : 475-480

Latigammaropsis savioi sp. nov.

( Figures 19–22 )

Type material. Holotype, male (5.95 mm, dissected and drawn, 1 slide), MZUSP 46925 , PROTRINDADE, Trindade Island , off Espírito Santo, Brazil, Enseada dos Portugueses (Farol), 14.6 m, 20°29’52.3”S – 29°19’15.6”W, JB Mendonça coll., 10.vii.2012 . Paratypes: 1 female (6.92 mm, dissected and drawn, 1 slide), MZUSP 45138 ; 9 females, MZUSP 46926 ; 1 male, 2 females, MOUFPE 22055 , same data as holotype . 1 male, 1 female, 1 ovigerous female, MZUSP 46927 , ibidem, 14 m depth, 20°29’52.3”S - 29°19’15.6”W, J.B. Mendonça coll., 22.iv.2014 . 2 males, 3 females, 1 juvenile, MZUSP 45133 , ibidem, Ponta da Calheta , 16.6 m, 20°30’18.7”S - 29°18’31.6”W, JB Mendonça coll., 23.vi.2016 . 2 males, 2 females, MZUSP 46929 , ibidem, 17 m, 20°29’32.0”S - 29°18’31.6”W, J.B. Mendonça coll., 28.iv.2014 . 1 male, 1 female, MZUSP 46928 , ibidem, Praia dos Portugueses (Rampa nova), 11 m, 20°30’17.7”S - 29°18’56.7”W, J.B. Mendonça coll., 23.iv.2014 .

Type locality. Enseada dos Portugueses, 20°29’52.3”S – 29°19’15.6”W, 14.6 m, Trindade Island , off Espírito Santo, Brazil .

Distribution. So far only known from Trindade Island, between 11 m and 17 m.

Etymology. This species is named after Domingos Sávio de Melo Pinto for his unwavering assistance and support to researchers committed to the study of Brazilian oceanic islands.

Diagnosis. Head eyes totally enclosed in the lateral cephalic lobe. Antenna 1 accessory flagellum with six articles. Sexual dimorphism strong. Gnathopod 2 subchelate, poorly setose; basis 1.6x longer than wide; carpus about 1/4 of propodus length, propodus subrectangular, 1.5x longer than wide; palm setose, acute, inclination of 50°, with large subrectangular process bearing five teeth, followed by a “U”-shaped excavation to form a large subacute process with long and robust setae defining the palmar corner; dactylus robust, recurved, fitting palm. Uropod 1 interramal spine acute, long, 0.4x of peduncle length. Uropod 2 peduncle shorter rami (0.6x). Uropod 3 peduncle 2x longer than wide, subequal to outer ramus length; inner ramus shorter than article 1 of outer ramus, tapering distally, outer ramus 2-articulate, article 1 with one marginal robust seta and three robust setae distally. Telson subquadrate, distolateral margin with pair of plumose setae near rounded knob, dorsal crest with two robust setae; distal margin truncate.

Description. Based on holotype.

Head with lateral cephalic lobes rounded, strongly produced. Eyes of medium size, rounded.Antenna 1 peduncle article 1 shorter than article 2 (0.7x); article 3 subequal in length to article 1; accessory flagellum 6-articulate, distal article minute. Lower lip inner and outer lobes pubescent apically; mandibular process well developed with acute lobes apically. Mandible incisor well developed; molar triturative; lacinia mobilis 4-dentate; accessory setal row with eight dentate setae; palp article 2 longest, setose; article 3 spatulate, heavily setose apically. Maxilla 1 inner plate with apex pointed, lateral margin lined with long slender setae; outer plate with 11 serrate robust setae; palp 2-articulated. Maxilla 2 inner plate slenderer than outer plate, with marginal row of long slender setae and oblique row of setae on the surface; outer plate rounded apically, with slender setae and lateral margin pubescent. Maxilliped inner plate with three apical robust setae; outer plate slightly longer than 1/2 of article 2 palp, with nine robust setae on inner margin to distal margin; palp 4-articulate, article 2 longest, bearing long slender setae, article 3 longer than article 4, setose; article 4 conical, with one apical robust seta.

Pereon. Gnathopod 1 subchelate, coxa subquadrate, almost as long as wide, anteroventral angle rounded; ventral margin not setose; basis slender, 2.3x longer than wide, anterior margin not setose; carpus slightly longer than propodus (1.2x), posterior margin setose, anterodistal angle with tuft of setae; propodus broadly subovate, anterior and posterior margins sparse setose, palm acute, finely serrate, and defined by a robust seta; dactylus falcate, overlapping palm. Gnathopod 2 subchelate, poorly setose; coxa subrectangular, 1.6x wider than long, ventral margin with sparse short setae; basis 1.6x longer than wide; carpus about 1/4 of propodus length, posterior margin with slender setae; propodus subrectangular, 1.5x longer than wide, anterior margin almost naked, anterodistal angle with tuft of slender setae, posterior margin with nine tufts of slender setae; palm setose, acute, inclination of 50°, with large subrectangular process bearing five teeth, followed by a “U”-shapped excavation to form large subacute process with a robust and long setae defining palmar corner; dactylus robust, recurved and fitting palm. Pereopods 3–4 similar in shape, slender; coxae almost as long as wide, basis slightly inflated, 2.7x longer than wide, with few short setae; merus longer than propodus (1.2x); carpus shorter than merus (0.7x); propodus longer than carpus (1.2x); dactylus robust and falcate. Pereopods 5 coxa bilobate, anterior lobe deeper, broadly rounded; basis subovate, almost as long as wide; merus slightly longer than carpus (1.2x), posterodistal angle with a long slender seta; carpus with a robust slender seta on posterodistal angle; propodus with distal part broken, posterior margin with three robust setae increasing in length. Pereopod 6 coxa weakly bilobated, lobes subequal in length; basis 1.3x longer than wide; merus longer than carpus (1.2x), posterodistal angle without a robust seta; carpus with tuft of slender setae on posterodistal angle; propodus 4.7x longer than wide, posterior margin with three robust setae and tuft of very long setae distally; dactylus robust and falcate. Pereopod 7 coxa subovate; basis 1.6x longer than wide; merus longer than carpus (1.2x), posterodistal angle with two slender setae; carpus with tuft of slender setae on posterodistal angle; propodus 5.4x longer than wide, posterior margin with three robust setae, posterodistal angle with tuft of very long setae; dactylus robust and falcate.

Pleon. Uropod 1 peduncle longer than outer ramus (1.5x), dorsal margin with five robust setae; interramal spine acute and long, 0.4x of peduncle length; outer ramus with three robust marginal setae and four robust setae distally; inner ramus with two robust marginal setae and four robust setae distally. Uropod 2 peduncle shorter than both rami (0.6x), outer dorsal margin with two robust setae; outer ramus with two lines of five robust setae on both inner and outer margins, two robust setae distally; inner ramus with two robust setae on inner margin with line of five robust setae on outer margin, four robust setae apically. Uropod 3 peduncle 2x longer than wide, subequal to outer ramus length, distal margin with two robust setae; inner ramus shorter than article 1 of outer ramus, tapering distally, medially two robust setae and apical robust seta; outer ramus 2-articulate, article 1 with one marginal robust seta and three robust seta distally; article 2 short, 0.06x of article 1 length, with two long setae distally. Telson subquadrate, 1.2x longer than wide, lateral margin with two pairs of short setae proximally and pair of plumose setae on distal third, distolateral margin with pair of plumose setae near rounded knob, dorsal crest with two robust seta; distal margin truncate.

Female (sexually dimorphic characters only)

Females very similar to males, differing from males only in the less robust gnathopod 2. Gnathopod 2 carpus 0.6x of propodus length, posterior margin weakly lobate with a tuft of slender setae; propodus subrectangular, 1.6x longer than wide; palm acute, sinuous, palmar corner defined by a long robust setae; dactylus long, overreaching palm.

Remarks. Latigammaropsis savioi sp. nov. concur with L. photisimilis ( Ruffo, 1969) from the Red Sea and L. gemina ( Myers, 1995) from Papua New Guinea, in having long lateral cephalic lobe, eyes rounded and totally encased within the lateral cephalic lobe, propodus of male gnathopod 2 rectangular with palm defined by a strong spine. However, the new species can be readily distinguished from L. photisimilis (characters for the later species in brackets) by its lateral cephalic lobe rounded (vs. cephalic lobe acute); palm of male gnathopod 2 acute, bearing subrectangular and multidentate process followed by a shallow “U”-shapped excavation and palmar corner provided with a robust seta (vs. palm transverse, bearing a triangular process followed by a deep “U”-shapped excavation and palmar corner without a robust seta); dactylus of male gnathopod 2 fitting palm (vs. dactylus overreaching palm); and distal margin of telson truncate (vs. distal margin of telson with a subtriangular process).

Latigammaropsis savioi sp. nov. differs from L. gemina as follows (characters for L. gemina in brackets): eyes large (vs. small eyes); lateral cephalic lobe broad (vs. slender lobe); article 3 of mandibular palp strongly spatulate (vs. article 3 weakly spatulate); inner ramus of uropod 3 with one marginal robust seta on inner margin (vs. lacking such seta on inner margin); and lateral margin of telson with plumose setae (vs. lateral margin naked).

Latigammaropsis savioi sp. nov. stands apart from L. oliveirai sp. nov. in the eyes ovate and totally encased within the cephalic lobe, male and female gnathopod 2 dissimilar to each other, propodus of male gnathopod 2 1.4.x longer than wide and with a multidentate process and a deep “U”-shapped excavation on palm; inner ramus of uropod 3 shorter than article 1 of outer ramus, and telson with a distal margin truncate. In contrast, in L. oliveirai sp. nov. the eyes are reniform and only partially encased within the cephalic lobe, the male and female gnathopod 2 are similar to each other, the propodus of the male gnathopod 2 is 1.9.x longer than wide and lacks the multidentate palmar process, the inner ramus of uropod 3 is subequal in length to article 1 of outer ramus, and the telson is provided with a distal subacute process.

Figures

FIGURE 19. Latigammaropsis savioi sp. nov. Holotype, male (5.95 mm), Habitus, Trindade Island, off Espírito Santo, Brazil, 14.6 m, 20°29’52.3”S–29°19’15.6”W, 10.vii.2012, MZUSP 46925. Mouthparts, paratype female (6.92 mm) same data as holotype, MZUSP 45138. Abbreviations: Hb, habitus; LL, lower lip; Md, mandible; Mx, maxilla; Mxp, maxilliped. Scale bars = 0.5 for habitus and 0.1 mm for the remains.

FIGURE 20. Latigammaropsis savioi sp. nov. Holotype, male (5.95 mm), gnathopod 2, Trindade Island, off Espírito Santo, Brazil, 14.6 m, 20°29’52.3”S–29°19’15.6”W, 10.vii.2012, MZUSP 46925. Gnathopods 1-2 paratype female (6.92 mm) same data as holotype, MZUSP 45138. Abbreviations: G, gnathopod; m, male, f, female. Scale bars = 0.1 mm.

FIGURE 21. Latigammaropsis savioi sp. nov. Paratype, female (6.92 mm), pereopods 3-7, Trindade Island, off Espírito Santo, Brazil, 14.6 m, 20°29’52.3”S–29°19’15.6”W, 10.vii.2012, MZUSP 45138. Abbreviations: P, pereopod. Scale bars = 0.1 mm.

FIGURE 22. Latigammaropsis savioi sp. nov. Paratype, female (6.92 mm), Uropods 1-3 and telson, Trindade Island, off Espírito Santo, Brazil, 14.6 m, 20°29’52.3”S–29°19’15.6”W, 10.vii.2012, MZUSP 45138. Abbreviations: T, telson; Ur, uropod. Scale bars = 0.1 mm.