Hippolyte ngi, Zhibin, Gan & Xinzheng, Li, 2017

Zhibin, Gan & Xinzheng, Li, 2017, A new species of the genus Hippolyte (Decapoda: Caridea: Hippolytidae) from South China Sea and Singapore, Zootaxa 4258 (1) : -

publication ID	https://doi.org/ 10.11646/zootaxa.4258.1.2
publication LSID	lsid:zoobank.org:pub:B6303D3A-7509-4ACB-B526-97147B36461A
DOI	https://doi.org/10.5281/zenodo.6028504
persistent identifier	https://treatment.plazi.org/id/03B94B7B-FFEF-383C-FF49-12560A27FE42
treatment provided by	Plazi
scientific name	Hippolyte ngi
status	sp. nov.

Treatment

Hippolyte ngi View in CoL spec. nov.

( Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 )

Material examined. Holotype: ZRC 2010.0349 View Materials , ovigerous female, 1.7 mm CL, Subar Laut Island, Singapore, 2–5 m, Coll. J. Low, 17 October 2010 . Paratypes: MBM 285041, 1 male, 1.3 mm CL, Hainan Island, China, 1–3 m Coll. Z. B. Gan, 6 May 2015 ; ZRC 2010.0346, 1 female, 1.5 mm CL, St. John’s Island , Singapore, 1–2 m, Coll. J. Low, 23 September 2010 ; ZRC 2010.0347, 2 ovigerous females, 1.6–1.8 mm CL, St. John’s Island , Singapore, 2–4 m, Coll. J. Low, 23 September 2010 ; ZRC 2010.0348, 1 ovigerous female, 1.6 mm CL, St. John’s Island , Singapore, 1– 3 m, Coll. J. Low, 23 September 2010 .

Description. Outline moderately robust ( Fig. 1 View FIGURE 1 ). Ratio lateral length/height of carapace 1.5–1.7. Rostrum narrow and long, slightly recurved in middle length, slightly shorter than carapace, distinctly overreaching antennular peduncle but falling short of scaphocerite apex. Rostrum without lateral carina, with only one dorsal tooth in proximal position and two ventral teeth in the distal third position ( Fig. 2 View FIGURE 2 A). Carapace smooth and glabrous, with robust supraorbital spine, antennal spine and hepatic spine ( Fig. 2 View FIGURE 2 A). Base of supraorbital spine posterior to posterior orbital margin. Tip of antennal spine slightly overreaching inferior orbital angle. At least distal half of hepatic spine overreaching anterior edge of carapace. Inferior orbital angle and pterygostomial region strongly produced ( Fig. 2 View FIGURE 2 A).

Abdominal segments smooth ( Fig. 1 View FIGURE 1 ). Third abdominal segment geniculately curved. Ratio dorsal length/ height of the sixth abdominal segment 2.0–2.1. Telson ( Fig. 2 View FIGURE 2 B) slightly longer than sixth abdominal segment; posterior margin truncate, armed with eight strong spines, outer spines smallest and medial two longest, without intermediate spinules. Dorsal surface armed with two pairs of spines situated on proximal 0.5 and 0.8 length of telson.

Eye ( Fig. 2 View FIGURE 2 C) well developed; tip of cornea nearly reaching stylocerite apex when extended forward; unpigmented part of eyestalk slightly longer than broad; cornea semispherical, shorter than unpigmented part of eyestalk.

Antennular peduncle ( Fig. 2 View FIGURE 2 D) overreaching 0.5 of scaphocerite. First segment of antennular peduncle with one distolateral tooth; inner ventral tooth on 0.6 of first segment of antennular peduncle (excluding distolateral tooth); stylocerite medium-sized, reaching 0.64 (distolateral tooth included), or 0.73 (distolateral tooth excluded) of first segment of antennular peduncle. Second segment of antennular peduncle 1.2–1.3 times as long as broad in dorsal view, approximately 0.9–1.1 times as long as third segment in dorsal view. Outer antennular flagellum shorter and thicker than inner. Scaphocerite ( Fig. 2 View FIGURE 2 E) 2.5–2.7 times as long as wide, distolateral spine of scaphocerite far from reaching distal margin of blade; distolateral spine and blade separated by a distinct notch.

Mouthparts with morphology typical of the genus Hippolyte . Mandible ( Fig. 3 View FIGURE 3 A) with incisor process and molar process, without palp; incisor process with six teeth. Maxillula ( Fig. 3 View FIGURE 3 B) with simple and broad palp. Maxilla ( Fig. 3 View FIGURE 3 C) with lateral border of scaphognathite straight. Epipod of first maxilliped ( Fig. 3 View FIGURE 3 D) continuous with outer margin. Second maxilliped ( Fig. 3 View FIGURE 3 E) with epipod deeply bilobed. Third maxilliped ( Fig. 3 View FIGURE 3 F) reaching at most 0.4 of the scaphocerite when extended forward. Distal 0.4 ultimate segment of third maxilliped with eight to nine strong spines and some normal setae on inner border; ultimate segment (excluding apical spine) 1.4–1.5 times as long as penultimate segment; antepenultimate segment slightly shorter than ultimate segment and penultimate segment combined; exopod slightly exceeding mid-length of antepenultimate segment of third maxilliped.

First pereiopod ( Fig. 4 View FIGURE 4 A) moderately robust, slightly overreaching basicerite when extended forward. Ischium and merus furnished with few long plumose setae. Outer edges of fingers of chela not denticulate, but with tiny setules and long simple apical setae; tip of fixed fingers with three tooth-like spines; tip of dactylus with four toothlike spines.

Second pereiopod ( Fig. 4 View FIGURE 4 B) reaching to near distolateral spine of scaphocerite when extended forward. Carpus with three subsegments, first segment longest, about 1.4 times as long as third segment, 0.9 times as long as second and third segments combined; first segment 3.9 times as long as wide; second segment 1.5 times as long as wide; third segment 1.8 times as long as wide. Tip of fixed finger of chela with three tooth-like spines; tip of dactylus with four tooth-like spines, cutting edges not denticulate.

Third to fifth pereiopods long and robust. When extended forward, dactylus of third pereiopod ( Fig. 4 View FIGURE 4 B) reaching beyond terminal blade of scaphocerite. Merus 7.1 times as long as wide, armed with two lateral spines; carpus 3.2 times as long as wide, armed with one proximal lateral spine; propodus 7.5 times as long as wide, armed with six to eight pairs of spines on ventral margins. Dactylus with 11–13 spines; spines in a single row, in ventral and apical positions (none in dorsal or subdorsal positions); three large apical spines (slightly diminishing from apical to subapical, but all more than 2 times as long as ventral spines). Ratio length of third pereiopod dactylus with longest apical spine/length of propodus 0.4; ratio length of third pereiopod dactylus with longest apical spine/ length of carpus 0.78; ratio length of dactylus without spines/breadth of dactylus without spines 2.8; ratio length of dactylus with longest spines/breadth of dactylus without spines 5.0; ratio length of longest spine of dactylus / breadth of dactylus without spines 2.0. Fourth and fifth pereiopods ( Fig. 4 View FIGURE 4 D, E) similar in shape to the third pereiopod, but their length decreasing in order. Merus of fourth pereiopod armed with one lateral spine; merus of fifth pereiopod without lateral spine.

The only one male specimen more slender than female specimens, its rostrum unarmed on dorsal and ventral margin. Propodus and dactylus of third pereiopod of male specimen forming a prehensile apparatus ( Fig. 4 View FIGURE 4 F). Appendix masculina with ten apical setae, shorter than half length of appendix interna ( Fig. 4 View FIGURE 4 G).

Coloration. Generally sandy-brown over body ( Fig. 5 View FIGURE 5 ), mainly over carapace, eyestalk, scaphocerite, abdomen and telson. Pereiopods mainly transparent.

Habitat. All specimens were captured among gulfweed ( Sargassum sp.). The male specimen (MBM28504) was captured at a depth of 1–3 m, the Singaporean specimens at 1– 5 m.

Etymology. The new species is named after Dr. Peter K. L. Ng with respect and admiration for his contributions on crustacean taxonomy, and in appreciation for providing us with Hippolyte specimens from Singapore.

Distribution. The species is known only from its type locality, Subar Laut Island; as well as St. John’s Island and Hainan Island.