Goniodelphys indica Kim & Boxshall 2020, sp. nov.

Goniodelphysindica sp. nov.

(Figs. 106–108)

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21249), paratype (intact ♀, MNHN-IU-2014-21250)), and dissected paratype (♀, figured) from Ascidia fictile Monniot C., 1997 (MNHN-IT-2008-1016 = MNHN P5/ ASC.A/292), MUA20, Nosy Be, Madagascar, depth 27 m, P. Laboute coll., 08 October 1991.

Additionalmaterial. 8 ♂♂ (MNHN-IU-2018-1833) and 2 dissected specimens (1 copepodid V ♀, 1 ♂) from A. fictile, Nosy Be, Madagascar, collected by Laboute.

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Etymology. The new species is named for its geographic origin, the Indian Ocean.

Descriptionoffemale. Body (Fig. 106A, B) 3.70 mm long, with spindle-shaped prosome with flattened dorsal and ventrolateral surfaces 3.30 mm long, clearly segmented. Cephalosome 0.52×0.91 μm, much wider than long, semicircular in dorsal view, fringed with narrow membrane along posteriormargin both dorsally and laterally. First to fourth pedigerous somites 0.26×1.01, 0.39×1.14, 0.38×1.17, and 1.76×1.17 μm, respectively; first to third each fringed with narrow membrane along posterior margin. Fourth pedigerous somite forming brood pouch, longer than anterior prosomal somites combined, tapering in lateral view but with rounded posteriormargin in dorsal view. Fifth pedigerous somite fused with fourth. Free urosome cylindrical, 5-segmented, narrowing posteriorly. Anal somite (Fig. 106D) with highly sclerotized posteroventral protuberances bearing few long setules apically. Caudal ramus (Fig. 106D) positioned dorsally, about 2.3 times longerthan wide (145×64 μm); armed with 2 claws and 4 naked setae; lengths of claws 68 and 45 μm.

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Rostrum (Fig.106F)muchwiderthanlong,withsmall, nipple-shaped tubercle on rounded apex. Antennule (Fig. 106G) attenuated distally, 8-segmented; armatureformula 6, 10, 8+aesthetasc, 3, 2+aesthetasc, 2, 2+aesthetasc, and 7+aesthetasc; suture line between sixth and seventh segments indistinct; 2 proximal setae on first segment pinnate and much larger than other setae. Antenna (Fig. 106H) 4-segmented; coxashortand unarmed; basiswith exopod represented by 1 large pinnate seta and 1 vestigial seta at outer distal corner, ornamented with row of minute setules on inner surface; first endopodal segment with 1 small seta on inner side; compound distal endopodal segment about 3.6 times as long as wide; armed with 10 setae (distal 3 setae blunt at tip) plus small terminal claw, less than half as long as segment.

Labrum (Fig. 106I) simple, with convexdistal margin and 2 patches of minute spinules distally. Mandible (Fig. 107A) with 5 teeth, 1 proximal seta, distally bifurcate proximal extension, and 3 needle-like spinules between second and third distal teeth on coxal gnathobase; basis with 1 medial seta; exopod 2-segmented, armedwith 3 and 2 setae on first and second segments, respectively, all setae subequal in length; endopod incompletely segmented and armed with 4 and 9 setae on first and second segments, respectively; mediodistal seta on second segment very small. Paragnath (Fig. 107B) as simple lobe with setulose medial surface. Maxillule (Fig. 107C) with 9 setaeon arthrite, 1 broad seta on coxal endite, 2 setae on epipodite; basis with 3 setae on medial margin; exopod and endopod with 3 and 4 setae, respectively. Maxilla (Fig. 107D) 5- segmented; syncoxa with 3, 1, 2, and 2 setae on first to fourth endites, respectively; 3 on basis, and 1, 1, and 3 on first to third endopodal segments, respectively. Maxilliped (Fig. 107E) armed with 10 setae (8 medial and 2 apical).

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Legs 1–4 with 3-segmented rami (Fig. 107 F–H) but with articulation incomplete between second and third endopodal segments of leg 1. Exopods of legs 2–4 distinctly longerthan endopods. Coxa unarmed. Outer seta on basis very large in leg 1 (longer than rami), but small in legs 2–4. Inner distal spine on basis of leg 1 long and setiform, setulose proximally but spinulose distally. Armature formula for legs 1–4 as follows:

Leg 5 (Fig. 107I) consisting of short, lobate protopod and free exopod; protopod tipped with seta; exopod 59×34 μm, distally with 1 seta and 1 vestigial seta; mid-inner margin of exopod convex and spinulose.

Descriptionofmale. Body (Fig. 108A, B) slender, slightly depressed. Bodylength 1.29 mm. Dorsal shield of cephalosome with slightly extended, pointed posterolateral corners. Posterodorsal part of fouth pedigeroussomite only slightly extended. Urosome (Fig. 108C) 6-segmented: fifth pedigeroussomite free. First abdominal somite ornamented with rows of minute spinules on ventral surface. Anal somite (Fig. 108D) with smaller posterior process than in female, ornamented with scattered setules and minute spinules on ventral surface. Caudal ramus 34×25 μm, armed as in female.

Rostrum (Fig. 108E) 58×77 μm, only slightly wider than long, strongly tapering, with convex distal margin. Antennule armed as in female, but aesthetascs larger. Antenna as in female. Labrum and mandible as in female. Maxillule with 3 setae on endopod. Maxilla with 2 large setae on basis, lacking additional small seta. Maxilliped (Fig. 108F) armedwith 8 setae (6 medial and 2 apical).

Leg 1 with same armature formula as in female; endopod distinctly 3-segmented; innerdistal spine on basis strong, spinulose, and extending to middle of second segment. Exopods of legs 2–4 with well-developed outer and distal spines (Fig. 108G); longerthan endopods, as in female. Inner seta on second exopodal segment and proximal 2 inner setae on third exopodal segment of legs 2–4 rudimentary. Distalmost setaon third exopodal segment of legs 2–4 enlarged (longer than ramus). Armature formula for legs 2–4 as follows:

Leg 5 (Fig. 108H) protopod short, with outer distal seta; exopod 23×16 μm, unornamented, tapering with slightly convex outer margin, bearing single seta apically. Leg 6 (Fig. 108H) represented by 2 naked setae distally on genital operculum.

Copepodid V female. Body (Fig. 106C) 1.78 mm long. Prosome 1.59 mm long, with concave dorsal surface ornamented with numerous long setules but lacking membranous fringe along posterior margins of anterior somites. Other morphological aspects as in adult.

Remarks. The original description of G. trigona by Buchholz (1869) mentioned some specific characterstates which allow us to distinguish it from the new species. According to Buchholz (1869), G. trigona is characterised by the following: (1) the body length is 2 mm in the female and 0.7 to 0.8 mm in the male (vs. 3.70 mm in the female and 1.29 mm in the male of G. indica sp. nov.); (2) the cephalosome is triangular in dorsal view and slightly longer than wide (vs. rounded anteriorly and much wider than long in G. indica sp. nov.); (3) the terminal segment of the antenna widens towards the tip (vs. this segment is narrow along its whole length in G. indica sp. nov.); and (4) the endopod of leg 1 lacks an inner seta on the second and third segments (vs. these setae are present in G. indica sp. nov.). These marked differences support the recognition of the new species.

Goniodelphys indica sp. nov. was collected on the coast of Madagascar, in a different biogeographical region from G. trigona, which is known only from the Mediterranean (Illg & Dudley, 1965).

Although the original description (Illg, 1951) of G. clarki lacked detail, it can be distinguished from the new species by the markedly smaller female body of the former (2.2 mm) compared to the new species (3.70 mm), and by the possession of 2-segmented endopods in legs 1–4, rather than 3-segmented endopods as in the new species. The host of G. clarki was confirmed by Ooishi & Illg (1973) as Herdmania momus (Savigny, 1816) collected in Japanese waters.