Lysmata leptodactylus, Gan, Zhibin & Li, Xinzheng, 2016

Gan, Zhibin & Li, Xinzheng, 2016, Lysmata leptodactylus, a new species of lysmatid shrimp (Crustacea: Decapoda: Caridea) from China, Zootaxa 4138 (1), pp. 181-188 : 182-187

publication ID	https://doi.org/ 10.11646/zootaxa.4138.1.9
publication LSID	lsid:zoobank.org:pub:0C0D4579-2F12-4480-9E7D-93102121EF1C
DOI	https://doi.org/10.5281/zenodo.5668585
persistent identifier	https://treatment.plazi.org/id/707C3C2B-FFE5-F236-FF71-FC87FC5C6964
treatment provided by	Plazi
scientific name	Lysmata leptodactylus
status	sp. nov.

Treatment

Lysmata leptodactylus sp. nov.

( Figures 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Type material. Holotype: MBM 129616, ovigerous hermaphrodite, 6.1 mm CL, Taishan coast, Guangdong Province, the South China Sea, 2–6 m, Coll. J. Y. Liu, No. 54-096, 31 October 1954. Paratypes: MBM 189220, 1 male, 5.6 mm CL, 2 hermaphrodite, 5.4–5.6 mm CL, 5 ovigerous hermaphrodite, 5.2–6.3 mm CL, other information same as the holotype; MBM 129624, 2 male, 6.5–7.0mm CL, 1 hermaphrodite, 6.5 mm CL, 2 ovigerous hermaphrodite, 6.8–7.2 mm CL, Haimen coast, Guangdong Province, the South China Sea, 3–9 m, Coll. J. Y. Liu, No. 56-K235, 12 March 1956; MBM 136663, 5 male, 6.2–7.0 mm CL, 9 hermaphrodite, 6.1–7.0 mm CL, 2 ovigerous hermaphrodite, 7.2–7.4 mm CL, shanwei coast, Guangdong Province, the South China Sea, 2–16 m, Coll. J. Y. Liu, No. 56-K223, 4 March 1956; MBM 129613, 1 ovigerous hermaphrodite, 8.6 mm CL, Guanghai coast, Guangdong Province, the South China Sea, 8 m, Coll. J. Y. Liu, No. 56-K318, 26 March 1956.

Description. Medium-sized shrimp of Lysmata (5.2–8.6 mm CL in present material), with long antennular and antennal flagella. Carapace ( Fig. 1 View FIGURE 1 A, B, C) smooth and glabrous, with robust antennal spine and moderate pterygostomial spine. Orbit feebly developed, suborbital angle bluntly triangular, anterior margin slightly convex and partly fused with the base of antennal spine. Mid-dorsal line of carapace with well-developed epigastric spine, distinctly demarcated from rostral teeth. Hepatic and branchiostegal spines absent.

Rostrum ( Fig. 1 View FIGURE 1 C) broad, slightly curved upward at the tip, about 0.5–0.6 times as long as carapace, reaching about mid-length of second segment of the antennular peduncle, with medium-developed lateral carina; dorsal margin armed with 5–8 (mostly 7) subequal teeth, nearly equidistantly spaced, the proximal tooth situated exactly above the posterior margin of orbit; ventral margin armed with 3–5 (usually 4) small teeth, all distal to level of antepenultimate dorsal tooth.

Abdomen smooth and glabrous ( Fig. 1 View FIGURE 1 D). Pleura of first four abdominal somites with rounded margins, that of the fifth somite with sharp posterolateral tooth. Sixth somite with acute setose posteroventral angle, and acutely produced posterolateral angle; 1.4–1.6 times longer than fifth somite. Telson ( Fig. 1 View FIGURE 1 E) 1.3–1.7 times as long as the sixth abdominal somite, tapering posteriorly; posterior margin medially acute, armed with two pairs of spines laterally, medial pair longer and stronger, between the long and strong spines present two long plumose setae and some slender setae; dorsal surface with two pairs of spines situated at about one third to two three of telson length respectively; posterior three quarters of telson margin furnished with long and slender setae.

Eye well developed, not reaching dorsal margin of rostrum; cornea semispherical, longer and broader than stalk.

Antennular peduncle ( Fig. 1 View FIGURE 1 F) not reaching the end of scaphocerite. Proximal segment nearly equal to the length of distal two segments combined, with well-developed stylocerite reaching to about three quarters the length of proximal segment, distal margin armed with a transverse row of 3–5 (usually 4) disto-dorsal spinules and many delicate setae. Intermediate segment slightly longer than distal segment, 3–4 (mostly 4) disto-dorsal spinules and delicate setae present on the distal margin. Distal segment armed distally with a single disto-dorsal spinule and small delicate setae. Antennular flagella subequal in length; dorsolateral flagellum with one segment of vestigial accessory branch ( Fig. 1 View FIGURE 1 G); from the second segment to the accessory branch (21–29 segments), each segment furnished with groups of aesthetascs and thicker than the other segments. Antennal basicerite short with acute tooth on outer distal margin ( Fig. 1 View FIGURE 1 A); scaphocerite 3.0–3.5 times as long as wide, distolateral tooth well-developed, distinctly overreaching distal margin of blade ( Fig. 1 View FIGURE 1 H).

Mouthparts typical for genus. Mandible ( Fig. 2 View FIGURE 2 A) without incisor process or palp, molar process strong, with seven acute teeth situated disto-laterally. Maxillule ( Fig. 2 View FIGURE 2 B) with palp bilobed distally, each with several long setae at the distal margin; upper lacinia broad with dense long setae marginally; lower lacinia flagelliform, with two rows of simple long setae along the subdistal margin. Maxilla ( Fig. 2 View FIGURE 2 C) with elongated slender palp, with four terminal long setae; inner lacinia bilobed, outer margin furnished with row of long setae; scaphognathite welldeveloped, outer margin densely setose; proximal endite feebly developed, sparsely covered with short setae. First maxilliped ( Fig. 2 View FIGURE 2 D) with three-segmented endopod, extending slightly beyond the level of distal margin of caridean lobe; exopod well-developed, with several segments and dense long setae located distally; caridean lobe moderately developed; distal endite broad, mesial margin concave, setose; epipod deeply bilobed. Second maxilliped ( Fig. 2 View FIGURE 2 E) with endopod normal, dactylar segment short but very broad, terminal margin furnished with row of long spinous setae and simple setae, articulated with the lower distal border of propodus; epipod bilobed, with small podobranch. Third maxilliped ( Fig. 2 View FIGURE 2 F) with endopod overreaching level of terminal blade of scaphocerite by 0.6–0.8 length of ultimate segment; ultimate segment 1.2–1.6 times as long as penultimate segment, distolaterally armed with 5–7 spines; penultimate and ultimate segments furnished with rows of setae; proximal segment 2.1–2.3 times as long as the penultimate segment; exopod slender, slightly exceeding the midlength of proximal segment; coxa with terminal hooked epipod.

First four anterior pereiopods with well-developed terminal hooked epipods. First pereiopod ( Fig. 3 View FIGURE 3 A) moderately robust, reaching to or slightly overreaching terminal blade of scaphocerite. Fingers about 0.4 times as long as palm; chela, simple, subequal to the length of carpus, terminal margin furnished with tufts of long setae. Merus 1.1–1.3 times as long as carpus, obliquely articulated with ischium.

Second pereiopods ( Fig. 3 View FIGURE 3 B, C) longer and more slender than other pereiopods, distinctly unequal in length, each segment of the major second pereiopod 1.2–1.5 times as long as the corresponding minor segment. Major second pereiopod ( Fig. 3 View FIGURE 3 B) exceeding terminal blade of scaphocerite by lengths of entire carpus and chela. Chela small, slightly longer than the terminal sub-segment of carpus, dactylus shorter than the half length of propodus, fingers with tufts of terminal setae. Carpus elongate, about two times as long as merus, composed of 25–30 subsegments, distal subsegment longest. Merus subequal to ischium, composed of 22–26 subsegments. Ischium with row of hooked setae proximo-ventrally, distal end subdivided into five subsegments, with the proximal two joints faintly visible. Minor second pereiopod ( Fig. 3 View FIGURE 3 C) similar to the major one, exceeding terminal blade of scaphocerite by length of distal 0.7 of carpus and chela. Carpus composed of 24–28 subsegments. Merus composed of 18–25 subsegments. Ischium subdivided into three subsegments distally.

Third pereiopod ( Fig. 3 View FIGURE 3 D) reaching beyond terminal blade of scaphocerite by length of the distal half of carpus, propodus and dactylus. Dactylus ( Fig. 3 View FIGURE 3 E) elongate, about 0.3 the length of propodus, ending in a long tapered single tooth, flexor margin armed with five proximal small spines, penultimate spine being the largest and decreasing in size proximally, ultimate spine hide within tufts of long setae. Propodus longer than carpus, armed with five or six spines on postero-ventral and disto-ventral margins. Carpus unarmed, disto-dorsally with tufts of setae. Merus 1.6–2.2 times as long as carpus, armed with 5–8 robust spines on lateral surface. Ischium about one third the length of merus, unarmed. Fourth and fifth pereiopods ( Fig. 3 View FIGURE 3 F, G) similar in shape to the third pereiopod, each segment slightly shorter than that of third pereiopod. Merus of fourth pereiopod armed with 4–7 robust spines on disto-lateral surface; merus of the fifth pereiopod armed with 3–4 robust spines on disto-lateral surface.

First pleopod of hermaphrodites ( Fig. 3 View FIGURE 3 H) with endopod tapered, about 0.8 times as long as exopod, distally unarmed, interior margin furnished with dense long setae, outer edge furnished with normal setae. Second pleopod of the male ( Fig. 3 View FIGURE 3 I) having both appendices interna and masculina; appendix masculina slightly overreaching level of midlength of appendix interna, furnished with five long simple setae distally and three short setae sub-distally; appendix interna with terminal end slightly curved, terminal margin armed with a number of coupling hooks.

Uropod ( Fig. 1 View FIGURE 1 E) longer than telson. Exopod slightly longer than endopod, outer margin straight, diaeresis distinct, armed with a large movable spine flanked both laterally and mesially by a small acute tooth.

Eggs numerous and small, 0.3 × 0.5 mm.

Character Lysmata olavoi Lysmata dispar Lysmata lipkei L. leptodactylus n. sp. Lysmata vittata Rostrum Length (refer to Reaching enđ of seconđ Reaching enđ of first Reaching or slightly Reaching miđ-length of Slightly beyonđ enđ of antennular peđuncle) segment segment exceeđing enđ of seconđ seconđ segment seconđ segment segment

Color in life. Unknown.

Habitat. The new species is commonly found in the soft sediments (mainly mud) at the depth of 2– 16 m. The holotype and most of the paratypes (MBM189220, MBM136663 and MBM129613) occurred in the adjacent sea of Pearl Estuary.

Etymology. Greek “leptos”, means thin, slender, weak; Greek “daktylos”, menas finger. The specific name refers to the slender dactyli of the third to fifth pereiopods in the new species.