Laomenes clarki, Marin, Ivan, 2009

Marin, Ivan, 2009, Crinoid-associated shrimps of the genus Laomenes A. H. Clark, 1919 (Caridea: Palaemonidae: Pontoniinae): new species and probable diversity, Zootaxa 1971, pp. 1-49 : 13-18

publication ID	https://doi.org/ 10.5281/zenodo.185020
DOI	https://doi.org/10.5281/zenodo.6213140
persistent identifier	https://treatment.plazi.org/id/03DC87A3-9575-F632-F1D4-2A43FB2425D5
treatment provided by	Plazi
scientific name	Laomenes clarki
status	sp. nov.

Treatment

Laomenes clarki View in CoL sp. nov.

( Figs. 13–19 View FIGURE 13 View FIGURE 15 View FIGURE 16 View FIGURE 17 View FIGURE 18 View FIGURE 19 )

Material. Vietnam, Nhatrang Bay: 1 ovigerous female (holotype, pcl. 5.5 mm) and 1 male (paratype, pcl. 3.2 mm) ( ZMMU), Nok Island, 15 m, on crinoid Zygometra cf. punctata , 4.ix.2006, coll. I. Marin; 1 male (pcl. 1.5 mm) ( ZMMU), Mun Island, 10–12 m, on crinoid Zygometra sp., 29.xi.2006, coll. I. Marin; 1 male (pcl. 1.8 mm) ( ZMMU), Nok Island, 10 m, on crinoid Zygometra cf. punctata , 25.xi.2006, coll. I. Marin.

Description. Holotype female: Carapace swollen, smooth, with antennal and prominent hepatic teeth ( Fig. 8 View FIGURE 8 A, 9A, B); hepatic tooth larger than antennal; antennal tooth sharp and slender. Rostrum long, slender, slightly compressed, slightly turned down, with 5 teeth along dorsal carina; ventral margin straight, with single tooth; proximal lateral rostral lamina well developed, with conspicuous supraocular teeth ( Fig. 9 View FIGURE 9 A, B). Orbit well developed, inferior orbital angle slightly produced, rounded distally. Pterygostomial angle rounded, not projected.

Abdominal somites smooth; pleura of abdominal somites I–V rounded ( Fig. 8 View FIGURE 8 A). Telson ( Fig. 9 View FIGURE 9 J) about 3 times longer than wide in proximal part, narrowing posteriorly, with 2 pairs of small dorsal spines arising close to lateral margins at 0.5 and 0.75 of telson length; 3 pairs of posterior spines contain short stout lateral, long slender intermediate and slender submedial spines slightly longer than half length of intermediate spines.

Eyes ( Fig. 9 View FIGURE 9 C) large and well developed, with projecting subovate cornea. Central cornea with small blunt apical papilla. Well marked accessory pigmented spot presents posterodorsally.

Antennule ( Fig. 9 View FIGURE 9 D) well developed; basal segment about twice longer than wide, with distolateral angle bearing slender acute distolateral tooth and medial rounded projection (lobe) ( Fig. 9 View FIGURE 9 F); distinct submarginal ventral tooth situates near medial border of basal segment ( Fig. 9 View FIGURE 9 E), with well developed stylocerite; intermediate segment slender, as long as wide, with distolateral margin produced distally; distal segment as long as wide.

Antenna ( Fig. 9 View FIGURE 9 G) well developed, basicerite with well developed lobe, with large sharp distoventral tooth, overreaching distal margin of the segment for half of its length; carpocerite stout, about twice longer than wide; flagellum well developed; scaphocerite wide, about 3 times as long as maximal width, overreaching intermediate antennular segment, with well developed acute distolateral tooth.

Epistomial horns well developed, sharp ( Fig. 9 View FIGURE 9 H). Mandible robust ( Fig. 10 View FIGURE 10 A), without palp; incisor process broad, with 1 large and 8 small terminal teeth ( Fig. 10 View FIGURE 10 B); molar process robust, with stout sharp distal teeth. Maxillule ( Fig. 10 View FIGURE 10 C) normal, with well developed bilobed palp; upper lacinia wide, slightly curved, flaring distally, with strong setae along distal margin; lower lacinia more slender, tapering distally, covered with simple setae. Maxilla ( Fig. 10 View FIGURE 10 D) with well developed, simple palp, pointed distally, with slender endites furnished with stiff, elongated setae; scaphognathite well developed, edging with plumose setae. Maxilliped I ( Fig. 10 View FIGURE 10 E) with completely fused endites, exopod well developed with large caridean lobe bearing plumose setae; epipod divided distally. Maxilliped II with well developed exopod ( Fig. 10 View FIGURE 10 F); propodus with straight distolateral margin, situated angularly to dactylar segment covered with slender simple setae; dactylus about 3 times longer than broad, with numerous setae along distal margin; epipod square; podobranch absent. Maxilliped III ( Fig. 10 View FIGURE 10 G) with slender segments, exopod well developed, slightly exceeding ischiomerus; ischiomerus about 4 times longer than maximal width, tapering distally; penultimate segment slender, about 4 times as long as wide; terminal segment slender, about 5 times as long as wide, with tufts of sparse long setae along ventrolateral margins; epipod ovate, lobed; small arthrobranch present.

Pereiopod I (Fig. 11A) with relatively slender chela and fingers; coxal segment with well developed curved lobe distoventrally; merus slender, about 6 times longer than wide; carpus long and slender, about 7 times longer than wide, flaring distally, with several long simple setae at carpo-propodal articulation; palm (Fig. 11B) about 2 times longer than wide, subcylindrical; dactylus and fixed finger about 4 times as long as wide, tapering distally, with cutting edges entire and tips bearing numerous setae.

Pereiopod II equal in size and shape; segments robust (Fig. 11C); coxal segment with well developed curved lobe distoventrally; ischium about 3 times longer than wide; merus about 4 times as long as wide, with straight margins; carpus (Fig. 11D, E) triangular, flaring distally, with distinct notch ventrolaterally; palm cylindrical, about 4 times as long as wide, with straight margins; fingers pointed, with acute, curved tips; fixed fingers slender, with cutting edge bearing small triangular teeth; dactylus slender, about 4 times as long as wide, with cutting edge bearing small but distinct triangular teeth along in its proximal half (Fig. 11F).

Pereiopod III ( Fig. 12 View FIGURE 12 A) slender, with segments unarmed; ischium about 2.5 times longer than wide; merus about 5 times as long as wide; carpus about 5 times as long as maximal width, tapering distally; propodus about 8 times as long as wide, slightly tapering distally, with straight and smooth margins, with small distoventral spine and tufts of long plumose setae distolaterally; dactylus ( Fig. 12 View FIGURE 12 B) elongated, about 1.5 times as long as maximal width, with long, sharp and curved unguis, accessory tooth well developed, turned forward, situated at the middle of ventral margin accompanied with tufts of long slender setae. Pereiopod III–V similar.

Pleopods normal. Uropods slender, slightly exceeding telson; distolateral margin of uropodal exopod with small fixed tooth and mobile spine.

Paratype male ( Fig. 8 View FIGURE 8 B, 13A): Generally similar to holotype female. Pereiopod II slightly dissimilar in size ( Fig. 13 View FIGURE 13 B, D). Fingers of pereiopod II different; right major cheliped shares stout fingers with curved tips ( Fig. 13 View FIGURE 13 C); left minor cheliped with fingers more slender ( Fig. 13 View FIGURE 13 E). Appendix interna slightly longer than appendix masculina, with numerous subterminal cincinnuli. Appendix masculina ( Fig. 13 View FIGURE 13 G) with 2 long terminal, 2 long subterminal plumose setae and 3 simple marginal setae distomedially.

FIGURE 11. Laomenes clarki sp. nov., ovigerous female. A, pereiopod I. B, same, chela. C, pereiopod II. D, E, same, carpus. F, same, fingers. Scale 1 mm.

Coloration. General coloration of the body in females is dark red corresponding to the coloration of the crinoid host (Fig. 14). Distal part of carapace, rostrum, eyestalks, antennule, antenna, telson and uropods lighter red than general body. Carapace with 2 light red longitudinal bands laterally and 2 wide transverse bands dorsally (Fig 14A, B). Several wide red bands transversing each segment of abdomen reaching the beginning of pleura, but never edging ventral margin of pleura (Fig. 14C). Males are completely red (Fig. 14D).

Remarks. Laomenes clarki sp. nov. can be easy distinguished from the species of the “ L.amboinensis ” group and other species of the genus by unusually long distoventral tooth on basicerite of antenna and elongated dactylus of pereiopod III. The coloration of this species clearly differs from L. amboinensis by the presence of 2 wide dorsal transverse bands on carapace (vs. 4 thin bands in L. amboinensis ) and the absence of lighter edging on the lateral and ventral margins of the abdominal pleura. For additional diagnostic diagnosis see remarks under L. pardus sp. nov.

Host. The specimens were collected from a zygometrid crinoid identified by author as Zygometra punctata A.H. Clark, 1912 (Zygometridae) ( Fig. 34 View FIGURE 34 D).

Etymology. The species is named in honour of American scientist Dr. Austin H. Clark (1880–1954), a specialist in taxonomy of Echinoderms, who suggested generic name for the genus as well as described crinoid host of the species — Zygometra punctata A.H. Clark, 1912 .

Distribution. The species is known only from the type locality, Nhatrang Bay, Vietnam.