Laomenes pestrushka, Marin & Chan & Okuno, 2012

Marin, Ivan, Chan, Tin-Yam & Okuno, Junji, 2012, Crinoid-associated pontoniine shrimps of the genus Laomenes Clark, 1919 (Decapoda, Caridea, Palaemonidae) from PANGLAO 2004 and KUMEJIMA 2009 Expeditions, with description of two new species, Zootaxa 3367 (1), pp. 103-114 : 104-107

publication ID	https://doi.org/ 10.11646/zootaxa.3367.1.10
DOI	https://doi.org/10.5281/zenodo.5253836
persistent identifier	https://treatment.plazi.org/id/D90D87B2-731A-2C03-FF6E-908CFC69FDE6
treatment provided by	Felipe
scientific name	Laomenes pestrushka
status	sp. nov.

Treatment

Laomenes pestrushka View in CoL n. sp.

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , 8a View FIGURE 8 )

Material examined. Holotype, ovigerous female (pcl. 3.1 mm) (RUMF-ZC-1399), paratype male (pcl. 2.2 mm) ( NTOU M00996 View Materials ), Pacific Ocean , Japan, Ryukyu Islands , Kume Island , KUMEJIMA 2009, stn. Dive 12, Torishima Islet, 26°19.683ʹN, 126°44.625ʹE, scuba diving, <20 m, 12 November 2009. GoogleMaps

Description. Holotype, ovigerous female ( Fig. 1a View FIGURE 1 ). Carapace swollen, smooth, with antennal and hepatic teeth ( Fig. 2b View FIGURE 2 ); antennal tooth sharp and slender, situated close to orbital angle, smaller than hepatic tooth. Rostrum long, deep, compressed laterally, and slightly directed downwards, with 5 large dorsal teeth and 1 small subapical tooth; ventral margin slightly convex, with 1 tooth situated at distal third of rostrum; rostral lamina well developed proximolaterally, with conspicuous sharp supraocular teeth ( Fig. 2a View FIGURE 2 ). Orbit well developed, inferior orbital angle slightly produced forward, rounded. Pterygostomial angle rounded, not projected.

Abdominal somites smooth; pleurae of abdominal somites I–IV rounded, that of somite V pointed ( Fig. 1a View FIGURE 1 ). Telson ( Fig. 3a View FIGURE 3 ) about 3 times as long as proximal width, narrowing distally, with 2 pairs of small dorsal submarginal spines at 0.4 and 0.7 of telson length. Distal margin of telson armed with 3 pairs of spines, consisting of 1 pair of short stout lateral spines, 1 pair of long slender intermediate spines and 1 pair of plumose medial slender spines that about twice shorter than intermediate spines.

Eyes ( Fig. 2a View FIGURE 2 ) well developed, large and stout, with subovate cornea. Eyestalk about 1.5 times as long as wide. Cornea with distinct but blunt apical papilla, bearing well marked accessory pigmented spot posterodorsally.

Antennule ( Fig. 2d View FIGURE 2 ) well developed; basal segment of peduncle about twice longer than wide, with distolateral angle bearing stout but acute distolateral tooth and medial convex projection (lobe) ( Fig. 2e View FIGURE 2 ); ventromedial tooth distinct, situated near medial border of basal segment; stylocerite well developed, acute; intermediate segment stout, about as long as wide, distolateral margin produced distally and laterally; distal segment stout, as long as wide.

Antenna ( Fig. 2f View FIGURE 2 ) well developed, basicerite with sharp distoventral tooth, slightly overreaching distal margin of segment; carpocerite stout, about as long as wide; flagellum well developed; scaphocerite wide, about 3 times as long as maximal width, overreaching antennular peduncle and rostrum, with well developed acute distolateral tooth not overreaching blade.

Epistomial horns well developed, sharp. Mouthparts characteristic for genus, without any specific feature.

Pereiopod I ( Fig. 2g View FIGURE 2 ) relatively slender; coxa with well developed and curved lobe distoventrally; basis as long as wide; ischium about 2.5 times longer than wide; merus about 7 times as long as wide; carpus equal in length to merus, about 7 times as long as wide, slightly flaring distally, with some long simple setae at carpo-propodal articulation; palm about 3 times as long as wide, subcylindrical; dactylus and fixed finger ( Fig. 2h View FIGURE 2 ) slender, tapering distally, slightly shorter than palm, about 4 times as long as wide, cutting edges entire, tips simple with numerous simple setae.

Pereiopods II similar in shape and equal size, relatively robust ( Fig. 1a View FIGURE 1 ); coxa with well developed and curved lobe distoventrally; basis as long as wide; ischium about 2.5 times as long as wide; merus about 3.5 times as long as wide, with straight margins and distoventral triangular projection; carpus subtriangular, stout, widening distally, with distinct distolateral notch; palm ( Fig. 2i, j, k View FIGURE 2 ) cylindrical, about 5 times as long as wide, with straight margins; fingers slender, equal to palm length, about 5.5 times as long as wide, tips acute and curved, cutting edges straight and each armed with distinct triangular teeth ( Fig. 2k View FIGURE 2 ).

Pereiopods III–V similar. Pereiopod III ( Fig. 3c View FIGURE 3 ) relatively robust; ischium about 2.5 times as long as wide; merus about 4 times as long as wide; carpus about 2.5 times as long as maximal width, tapering distally, distodorsal margin overhanging proximal part of propodus; propodus about 6 times as long as wide, margins straight, armed with 3 ventral spines and 1 pair of slender distoventral spines; distal third of propodus with transverse rows of long dense plumose setae on flexor surface and fringe of setae on distolateral margin ( Fig. 3d, e View FIGURE 3 ); dactylus ( Fig. 3e View FIGURE 3 ) with small accessory tooth at base of unguis and stout corpus, corpus about 1.5 times as long as maximal width, unguis elongate, acute and curved; accessory tooth small, acute, produced downward and perpendicular to basal part; tuft of long setae present at proximolateral surface of unguis.

Pleopods normal, without specific feature. Uropods slender, slightly exceeding telson ( Fig. 3a View FIGURE 3 ); distolateral margin of exopod with small fixed tooth and large mobile spine ( Fig. 3b View FIGURE 3 ).

Male paratype ( Fig. 1b View FIGURE 1 ). Generally similar to female. Rostral formula 6/1 ( Fig. 2c View FIGURE 2 ). Pereiopods II similar in shape and size ( Fig. 1b View FIGURE 1 ) .

Colouration Body blackish and covered with numerous small irregular dots ( Fig. 8a View FIGURE 8 ). Dots mostly yellowishgreen and some of them arranged as thin transverse bands on dorsal body and wide longitudinal band along lateral body; dots orange in rostrum, eyes, distal parts of antennular peduncle, scaphocerite, pereiopods and tailfan. Eggs dark-brown-green.

Etymology. The species is named after its multicoloured pattern. “ Pestrushka ” is a Latin transcription of a common Russian nick-name for multicoloured pets or agricultural animals.

Host. Unknown, but probably associated with black-yellow or black-green coloured species of the family Comasteridae (Echinodermata, Crinoidea) such as Capillaster multiradiatus (Linnaeus, 1758) or green-black coloured species of the genus Comanthus A.H. Clark, 1908 .

Distribution. All the examined specimens of this species are collected from the type locality, Kume Island, Ryukyu Islands, Japan. However, colour photographs from Sulawesi, Indonesia (see Marin 2009: fig. 35E, F, as Laomenes sp. “ salad ”) probably also refer to the present new species.

Remarks. The “ Laomenes amboinensis (De Man, 1888) ” species group is characteristic in bearing ventral rostral tooth, distoventral spines on propodi of ambulatory pereiopods and uropodal exopod armed with a distolateral tooth. Five species are known in this group, namely L. amboinensis , L. cornutus , L. clarki Marin, 2009 , L. pardus Marin, 2009 , and L. holthuisi . The present new species differs from L. amboinensis in having a shorter eyestalk, single ventral rostral tooth (vs. usually 2 ventral rostral teeth in L. amboinensis ), and a medial lobe on the distolateral margin of the basal segment of antennular peduncle (vs. such lobe absent in L. amboinensis ). The new species can be readily separated from L. cornutus by its relatively more slender eyestalk and chelipeds, different ornamentations in the distolateral margins of the propodi and dactyli of the ambulatory pereiopods (see Marin, 2009). From L. clarki , the new species differs mainly in the forwardly-directed rostrum (vs. more slender and downwardly-directed in L. clarki ), equal chelipeds (subequal in L. clarki ), and shape of the dactyli of ambulatory pereiopods. Laomenes pardus differs from the new species in having longer fingers of the chelipeds and different shape of the dactyli of ambulatory pereiopods. Laomenes holthuisi differs from the new species mainly in having swollen and dissimilar chelipeds (see Marin & Okuno 2010). Moreover, the colouration is very diagnostic in the “ L. amboinensis ” species group (see Marin 2009; Marin & Okuno 2010) and the colour pattern of L. pestrushka n. sp. distinctly differs from all other known species within the group.