Laomenes gyrophthalmus, 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 : 108-109

publication ID	https://doi.org/ 10.11646/zootaxa.3367.1.10
DOI	https://doi.org/10.5281/zenodo.5253838
persistent identifier	https://treatment.plazi.org/id/D90D87B2-731E-2C00-FF6E-934EFC25F86D
treatment provided by	Felipe
scientific name	Laomenes gyrophthalmus
status	sp. nov.

Treatment

Laomenes gyrophthalmus View in CoL n. sp.

( Figs. 4 View FIGURE 4 , 5 View FIGURE 5 , 8b View FIGURE 8 )

Material examined. Holotype, ovigerous female (pcl. 3.8 mm) ( NMCR), Philippines, Bohol Island, PANGLAO 2004 expedition, stn. R42 , Baclayon Takot , 9°37.1ʹN, 123°52.6ʹE, scuba diving, 8–22 m, 12 June 2004. GoogleMaps

Description. Holotype, ovigerous female ( Fig. 4 View FIGURE 4 ). Carapace swollen, smooth, with well developed antennal and hepatic teeth ( Fig. 5a, b View FIGURE 5 ); antennal tooth acute, smaller than hepatic tooth. Rostrum long, deep, compressed laterally, slightly directed downwards, dorsal border with 4 large teeth and 1 small subapical tooth; ventral boarder slightly convex, with 1 tooth situated at distal third; rostral lamina well developed proximolaterally, with distinct sharp supraocular teeth ( Fig. 5b View FIGURE 5 ). Orbit well developed, inferior orbital angle slightly produced and rounded. Pterygostomial angle rounded, not projecting.

Abdominal somites smooth; pleura of abdominal somites I–V rounded ( Fig. 4 View FIGURE 4 ). Telson ( Fig. 5e View FIGURE 5 ) about 3.5 times as long as proximal width, narrowing distally, with two pairs of small dorsal submarginal spines at 0.5 and 0.75 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 slender plumose medial spines about 0.6 times as long as intermediate spines.

Eyes ( Fig. 5a–c View FIGURE 5 ) well developed, large and stout, with rounded cornea. Eyestalk about 1.7 times as long as wide. Cornea rounded, without apical papilla. Distinct accessory pigmented spot present posterodorsally.

Antennule ( Fig. 5b View FIGURE 5 ) well developed; basal segment of peduncle about 1.5 times as long as wide, with distolateral angle bearing slender acute distolateral tooth, without medial projection (lobe) ( Fig. 5d View FIGURE 5 ); submarginal ventral tooth distinct, situated near medial border of basal segment; stylocerite well developed, acute; intermediate segment relatively slender, about 1.5 times as long as wide, distolateral margin produced distally and laterally; distal segment stout, wider than long.

Antenna well developed, basicerite with well developed lobe and sharp triangular distoventral tooth; carpocerite stout, about as long as wide; flagellum well developed; scaphocerite wide, about 3 times as long as maximal width, slightly overreaching antennular peduncle and rostrum, with well developed acute distolateral tooth which not overreaching blade.

Epistomial horns well developed, sharp. Mouthparts characteristic for genus and without specific features.

Pereiopod I ( Fig. 5f View FIGURE 5 ) slender; coxa with well developed and curved lobe distoventrally; basis stout, as long as wide; ischium about 3.5 times as long as wide, flaring distally; merus about 7 times as long as wide; carpus slender, longer than merus, about 8 times as long as wide, flaring distally, with some long simple setae at carpo-propodal articulation; palm about 2.5 times as long as wide, subcylindrical; dactylus and fixed finger slender, tapering distally, about 4 times as long as wide, slightly shorter than palm, cutting edges entire, tips densely setose.

Pereiopod II similar in shape and size, relatively slender ( Fig. 5g View FIGURE 5 ); coxa with well developed and curved lobe distoventrally; basis as long as wide; ischium about 3 times as long as wide; merus about 3.5 times as long as wide, with straight margins and distally projected distoventral margin; carpus subtriangular, about 1.5 times as long as wide, flaring distally, with distinct notch ventrolaterally; palm ( Fig. 5h View FIGURE 5 ) cylindrical, about 3.5 times as long as wide, with straight margins; fingers slender, about 3 times as long as wide, about 0.7 times of the palmar length, with acute, curved tips, cutting edges bearing distinct triangular teeth.

Pereiopods III–V similar. Pereiopod III ( Fig. 5i View FIGURE 5 ) relatively slender; coxa and basis as long as wide; ischium about 3.5 times as long as wide; merus about 4 times as long as wide; carpus about 4 times as long as maximal width, flaring distally, distodorsal margin overhanging proximal part of propodus; propodus about 6.5 times as long as wide, slightly tapering distally, margins straight and armed with 2 small ventral spines at its distal third and pair of slender distoventral spines, with long plumose setae fringing distoventral margin ( Fig. 5j View FIGURE 5 ); dactylus ( Fig. 5j View FIGURE 5 ) with basal part about 1.5 times as long as maximal width, unguis long, sharp and curved; accessory tooth small, triangular, directed forward, situated at proximal two-thirds of ventral dactylar margin and accompanied proximodorsally with tufts of long slender setae.

Pleopods usual for genus. Uropods slender, slightly exceeding telson; distolateral margin of exopod with small fixed tooth and movable spine.

Colouration. Body generally brown. Dorsal surfaces of carapace and abdomen covered with yellowish brown and violet thin transverse bands. Lateral carapace with row of short, thin oblique violet bands; ventrolateral border of carapace with thin longitudinal violet band and a large yellowish spot posteroventrally. Abdominal pleura covered with yellow transverse bands. Distal part of rostrum, upper orbits, dorsal eyestalk, uropods and distal part of telson yellowish. Pereiopods III to V with large yellowish spots at articulations ( Fig. 8b View FIGURE 8 ).

Etymology. The species is named after its rounded cornea of eye, which is unique within the genus; “ gyro ” (Greek) - circle, rounded; “ ophthalmos ” (Greek) - eye.

Host. Unknown.

Distribution. The species is only known from the type locality in the Philippines.

Remarks. The present new species is unique within the genus in having a rounded cornea of eyes; all other known species (including L. pestrushka n. sp. described above) have a distinct apical papilla on the cornea (see Marin 2009; Marin & Okuno 2010). On the other hand, this new species clearly belongs to the “ L. amboinensis ” species group in having ventral rostral tooth, distoventral spines on propodi of ambulatory pereiopods and uropodal exopod armed with distolateral tooth (see Marin 2009). Laomenes gyrophthalmus n. sp. is mostly similar to L. pardus but can be readily separated from the latter by the basal antennular segment lacking a distally projected medial lobe at the distolateral angle, shorter fingers of the chelipeds, and shorter ventral and distoventral spines on propodi of ambulatory pereiopods, as well as the character of the cornea.