Nematopalaemon tenuipes ( Henderson, 1893 )

Ashelby, Christopher W., Lin, Wei-Cheng, Grave, Sammy De & Chan, Tin-Yam, 2018, Notes on the shrimp genus Palaemon Weber, 1795 (Crustacea, Decapoda, Palaemonidae) and related genera from Taiwan, Zootaxa 4446 (4), pp. 575-595 : 579

Nematopalaemon tenuipes ( Henderson, 1893)

( Figs. 4 , 13B )

Previous Taiwan records. Chace & Bruce 1993: 39.

Material examined. Dasi fishing port, Yilan County, 1 male (pocl 11.9 mm), 25.XI.1994 ( NTOU M01212 ) ; same location, 1 female (pocl 10.8 mm), 05.XII.1998 ( NTOU M01211 ) ; Mailiao , Yunlin County, 3 males (pocl 9.1–13.1 mm), 3 ovig. females (pocl 15.0– 14.3 mm), 3 females (pocl 10.0– 10.2 mm), 29.X.2009 ( NTOU M01207 ) ; same location, 1 ovig. female (pocl 16.1 mm), 30.XI.2010 ( NTOU M01210 ) ; Dongang fishing port, Pingtung County, 2 males (pocl 10.5–10.6 mm), 1 ovig. female (pocl 17.6 mm), 1 female (pocl 11.5 mm), 05.VIII.1996 ( NTOU M01214 ) ; same location, 1 female (pocl 10.1 mm), 3.XI.2011 ( NTOU M00952 ) ; same location, 1 male (pocl 11.1-11.6 mm), 1 ovig. female (pocl 2.4 mm), 2 female (pocl 8.2-11.5 mm), 3.XI.2011 ( NTOU M01831 ) .

Diagnosis. Rostrum overreaching antennal scale; rostral formula: 1–3 + 5–6/2–6; shorter ramus of dorsal antennular flagellum fused for about two fifths its length; fingers of chela of second pereiopod more than twice length of carpus; dactyli of the third to fifth pereiopods greatly elongated and thread-like; sixth abdominal somite no more than 2/3 as long as postorbital carapace length.

Colour pattern. Body semi-translucent and scattered with tiny red chromatophores; distal parts of tailfan and rostrum reddish; eggs deep yellow.

Remarks. Chace & Bruce (1993) suggested that a thorough review of N. tenuipes material from across the entire Indo-Pacific was desirable to confirm the specific status of N. colombiensis ( Squires & Mora, 1971) which differs only from N. tenuipes by the proportionally longer sixth abdominal somite (3/4 as long as carapace in N. colombiensis vs. at most 2/3 as long as carapace in N. tenuipes ). In the Taiwanese material the sixth abdominal somite varies between 0.57 and 0.63 as long as the carapace. As is common in preserved material of Nematopalaemon , the characteristically elongated dactyli of the third to fifth pereiopods are damaged and missing in most of the present specimens.

Ecology. Littoral, shallow water to about 20 m; in brackish water as well as fully marine conditions.

Distribution. India, Burma, Thailand, Philippines and Taiwan. Records from South Africa, Somalia and New Zealand require confirmation. Chace & Bruce (1993) cite Taiwan in the distribution of this species but it is unclear where this record originates. The last author (TYC) had sent many palaemonid specimens from Taiwan to A.J. Bruce for examination in the early 1990s, likely including this species and thus assumed to be the basis for this record. The present work is the first detailed report of N. tenuipes from Taiwan.

Figures

FIGURE 4. Nematopalaemon tenuipes (Henderson, 1893). A–B, female (pocl. 11.5 mm); C, detached part (NTOU M01214). A) carapace, right lateral view; B) left second pereiopod, lateral view; C) right second pereiopod, chela, mesial view. Scale bars indicate 1.0 mm.

FIGURE 13. A) Leander tenuicornis (Say, 1818), Lanyu, Taitung County, IV.1993 (specimen not deposited); B) Nematopalaemon tenuipes (Henderson, 1893), female (pocl 10.08 mm), Dongang fishing port, Pingtung County (NTOU M01831); C) Palaemon concinnus Dana, 1852, ovigerous female (pocl. 12.5 mm), Jialeshuei Village, Pingtung County (OUMNH-ZC 2010-02-079); D) Palaemon debilis Dana, 1852, male (pocl 5.51 mm), Ludao, Taidong County (NTOU M02086); E) Palaemon modestus (Heller, 1862), Sun Moon Lake, Nantou County, date unknown (specimen not deposited); F) Palaemon orientis Holthuis, 1950, ovigerous female (pocl 12.2 mm), Donggang, Pingtung County (OUMNH-ZC 2010-02- 078).