Entomopsyllus aplanatus, Lee, 2025
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publication ID |
https://doi.org/10.5281/zenodo.16967319 |
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persistent identifier |
https://treatment.plazi.org/id/382A6976-BA61-7163-FF32-392A2F46299D |
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treatment provided by |
Felipe |
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scientific name |
Entomopsyllus aplanatus |
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sp. nov. |
Entomopsyllus aplanatus View in CoL n. sp. ( Figs. 21-23 View Fig View Fig View Fig )
https://zoobank.org/urn:lsid:zoobank.org:act:2A265E6C-
B851-4207-860E-4DD6E5B96470
Type material. Holotype (intact ♀; MABIK CR002577 91), intact paratypes (20 ♀♀, 2 ♂♂; MABIK CR002577 92), and dissected paratypes (2 ♀♀, 2 ♂♂) from washings of mixed species of sponges, Munseom , Seogwipo, Jeju Island (33°13 ʹ 39.4 ʺ N, 126°33 ʹ 48.2 ʺ E), SCUBA, at a depth of 56 m, collected by Taekjun Lee, on 25 April 2023. The holotype and intact paratypes have been deposited in the National Marine Biodiversity Institute of Korea ( MABIK), Seocheon. The dissected paratype is retained in the collection of I.-H. Kim. GoogleMaps
Etymology. The specific name is derived from the Latin aplanat (= flattened), referring to the flattened body of the new species.
Female. Body ( Fig. 21A View Fig ) extremely flattened dorsoventrally, oval in dorsal view. Mean body length (prosomal length) 1.19 mm (1.13-1.26 mm), based on 10 specimens. Body of figured and described specimen 1.22 mm long. Maximum width 0.84 mm. Prosome covering whole body, except distal part of caudal rami, consisting of cephalothorax and second to fourth pedigerous somites; lengths of these 4 somites 606, 115, 76, and 436 μm, respectively, measured along midline. Urosome ( Fig. 21B View Fig ) 3-segment- ed, consisting of genital complex and 2-segmented abdomen. Fifth pedigerous somite completely fused with genital double-somite to form genital complex. Genital complex 170 × 132 μm, consisting of broader proximal 47% and narrower remaining part; genital apertures positioned dorsolaterally at about proximal third of genital complex; ventrodistal part of genital complex bearing pair of oblique rows of spinules on each side ( Fig. 21C View Fig ). Two free abdominal somites 80 × 75 and 90 × 75 μm, respectively. Caudal rami widely separated from each other; each ramus ( Fig. 21D View Fig ) 2.96 times longer than wide (77 × 26 μm), armed distally with 6 setae and ornamented with thin setules on inner margin; setae II and VII naked, tipped on digitiform process; setae III and VI unilaterally pinnate; 2 median terminal setae (setae IV and V) bipinnate.
Rostrum absent. Antennule ( Fig. 21E View Fig ) slender, 17-segmented; first, third, sixth, fifteenth, and terminal segments bearing 1 seta, 8 setae, 7 setae, 2 setae + aesthetasc, and 11 setae, respectively; other segments bearing 2 setae each; all setae naked; aesthetasc on fifteenth segment thin; first segment longest, and third segment second longest. Antenna ( Fig. 21F View Fig ) consisting of coxa, basis, 1-segmented exopod, and 2-segmented endopod; coxa short, unarmed; basis unarmed but with longitudinal row of several denticles on proximal region; exopodal segment elongate, 71 μm long, longer than first endopodal segment, with 1 distal and 1 subdistal small setae and setules on margins; first endopodal segment 64 μm long, unarmed but ornamented with minute, distally bifurcate spinules in distal half of segment; second endopodal segment 33 μm long, bearing 4 setae (1 proximal, 1 subdistal, and 2 small, distal) and setules on all surfaces and tipped with spiniform claw of 64 μm long.
Oral siphon ( Fig. 21G View Fig ) consisting of short, expanded proximal part and long, slender distal part, extending to posterior margin of genital double-somite. Mandible ( Fig. 21H View Fig ) consisting of fibril-like stylet and slender palp; palp 2-segmented, proximal segment 45 μm long, distal segment arched, 77 μm long, setulose along convex margin, tipped with 2 unequal, naked setae (85 and 38 μm long, respectively). Maxillule ( Fig. 21I View Fig ) bilobed; outer lobe 64 μm long, spinulose along outer margin, tipped with 4 thin, naked setae; inner lobe 26 μm long, obscurely defined at base, tipped with 3 very unequal, thin setae (750, 197, and 68 μm long, respectively). Maxilla ( Fig. 22A View Fig ) stout; proximal segment with protruded outer margin proximally; distal segment strongly curved at subdistal region, bearing several spinules near distal third. Maxilliped ( Fig. 22B View Fig ) 6-segmented; armature formula 1, 1, 1, 2, 1, and 1 + claw; syncoxa with spinules at outer subdistal region; basis 152 μm long, bearing several minute spinules on outer margin and rudimentary inner seta; terminal segment 50 μm long, bearing patch of spinules in distal half; terminal claw 65 μm long.
Legs 1-3 ( Fig. 22C- E View Fig ) with 3-segmented rami. Leg 4 ( Fig. 22F View Fig ) with 3-segmented exopod, without endopod. Rami of legs slender. Inner coxal seta present in leg 1, but absent in legs 2-4. Basis of leg 1 with filiform inner distal seta and row of thin spinules near base of seta. Endopod of leg 1 arched, extremely slender, much longer than exopod. Outer distal corner of second endopodal segment of leg 3 bicuspid, but monocuspid in legs 1 and 2. Armature formula for legs 1-4 as follows:
Coxa Basis Exopod Endopod Leg 1 0-1 1-1 I-1; I-1; I, I, 4 0-1; 0-2; 0, 5 Leg 2 0-0 1-0 I-1; I-1; III, I, 4 0-1; 0-2; 0, 2, 2 Leg 3 0-0 1-0 I-1; I-1; III, I, 4 0-1; 0-1; 0, 1, 1 Leg 4 0-0 1-0 I-1; I-1; III, I, 4 lacking
Leg 5 ( Fig. 21B View Fig ) consisting of short protopod and elongated exopod; protopod not articulated from genital complex, with 1 small dorsodistal seta; exopodal segment arched, 173 × 17 μm, with 1 subdistal and 2 distal setae. Leg 6 ( Fig. 21J View Fig ) represented by 2 small, naked setae on genital operculum.
Male. Body ( Fig. 23A View Fig ) oval, 764 μm long. Prosome segmented as in female. Urosome ( Fig. 23B View Fig ) consisting of genital complex and 3-segmented abdomen. Genital complex roughly quadrate, wider than long. Anal somite longer than anterior abdominal somites. Caudal ramus 1.64 times longer than wide (36 × 22 μm), armed as in female.
Antennule 14-segmented, not geniculate; armature formula 1, 2, 8, 2, 2, 7, 2, 2, 4, 2, 2, 4, 4 + aesthetasc, and 11. Antenna as in female.
Oral siphon, mandible, maxillule, maxilla, maxilliped, and legs 1-4 not different from those of female. Leg 5 ( Fig. 23B View Fig ) exopodal segment 62 μm long, much shorter than that of female. Leg 6 ( Fig. 23B View Fig ) represented by 1 seta on distal apex of genital operculum.
Remarks. Currently, the genus Entomopsyllus includes five known species: E. adriae (Eiselt, 1959) , E. nicholsi McKinnon, 1988 , E. stocki Kim, 2004 , E. brevicaudatus Lee & Kim, 2017 , and E. takara Uyeno & Johnsson, 2018 . Among these, E. aplanatus n. sp. is most closely related to E. brevicaudatus , as both species exhibit a 17-segmented female antennule, four setae on the third endopodal segment of leg 2, four spines plus four setae (formula III, I, 4) on the third exopodal segment of leg 3, and two setae on the third endopodal segment of leg 3. However, E. aplanatus n. sp. differs from E. brevicaudatus by having four spines plus four setae (formula III, I, 4, rather than II, I, 4 as in E. brevicaudatus and other species) on the third exopodal segment of leg 2, and similarly on the third exopodal segment of leg 4. In the original description of E. brevicaudatus, Lee & Kim (2017) noted that the anal somite is unornamented. Therefore, the presence in E. aplanatus n. sp. of two pairs of rows of spinules on the ventral surface of the anal somite marks an additional distinctive difference from E. brevicaudatus .
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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