Lamprops tenuis, Tzareva & Vassilenko, 2006

Tzareva, Ludmila & Vassilenko, Stella, 2006, Two new species of Cumacea (Malacostraca, Peracarida) from Peter The Great Bay (Sea of Japan), Zootaxa 1174, pp. 41-48 : 42-43

Lamprops tenuis sp. nov. ( Figs. 1 , 2 )

Material examined

Holotype, ZIN­1/ 88378, female 6.0 mm (with telson) with rudiments of oostegites, Sea of Japan, Peter the Great Bay, near Furugelm Island, 27 Jul 1998, 10 m, dredge . Paratypes: collected at the type locality: ZIN­2/88379, 2 females 5.5 and 6.0 mm, with embryos on the II stage, 1 juvenile 3.2 mm long, 27 Jul 1998, 14 m, dredge; ZIN­3/88411, 1 juvenile 4.0 mm, 27 Jul 1998, 7 m, dredge; ZIN­4/88412, 2 juveniles 3.5 and 3.7 mm, 30 Jul 1998, 14 m, dredge; ZIN­5/88413, 1 juvenile 4.0 mm, 2 Aug 1998, 3.5 m, dredge; ZIN­ 6/883414, 1 juvenile 3.3 mm, 26 Aug 1998, 11 m, dredge; ZIN­7/88415, 1 female 5.7 mm, 4 Sep 1998, 17 m, dredge.

Diagnosis

Body thin and slender, integument translucent. Front part of carapace truncated, without subrostral notch. One fold developed on carapace lateral sides. Suture on frontal field not crossing fold on lateral part of carapace, and situated parallel to it. Telson with four pairs of lateral spines and five apical spines of different length: median spine thicker and shorter than two lateral spines; submedian spine very short, half as long as median spine.

Description of holotype

Female ( Fig. 1A ). Body thin and slender, integument translucent. Front part of carapace ( Fig. 1 , B) truncated, subrostral notch not pronounced. Mid­dorsal carina evident in anterior part of carapace. Narrow depression in posterior dorsal part of carapace. One fold developed on carapace lateral sides. In lateral view, fold extends from subrostral angle parallel to mid­dorsal carina, then turning upwards and forwards to end of mid­dorsal carina. Suture on frontal field not crossing fold on lateral part of carapace, and situated parallel to it. Eye small and rounded.

Maxilliped III ( Fig. 2C ) with long basis exceeding combined length of all other segments, inner distal angle with 2 long plumose setae; ischium and merus almost equal in length and width; carpus and propodus 2 times longer than ischium and merus, and also equal in length.

Pereopod I ( Fig. 2D ) slender, propodus and dactylus of equal length, basis on lower distal edge with three spinous setae.

Pereopod II ( Fig. 2A ) greatly shorter than pereopod I. Merus two times wider than carpus­dactylus. Carpus in distal part with 3 spines of different lengths; dactylus 1.2 times longer than propodus, with 3 spine­like terminal setae.

Pereopod III ( Fig. 2B ) with small 2­segment endopod; basis elongated with few setae; merus and carpus equal in length and width. Carpus with 3 long setae in distal part, Propodus with 1 long seta. Ischium with 2 long setae.

Telson ( Fig. 1C ) 1.5 times longer than last abdominal somite, gradually narrowing towards distal end and bearing four pairs of lateral small spines and five apical spines of different length: median spine thicker and shorter than lateral spines; submedian spines very short, half as long as median spine.

Length of uropodal peduncle ( Fig. 1C ) slightly shorter than length of telson; uropodal endopod as long as peduncle; exopod slightly shorter than endopod; endopod with three articles, third article longer than second article, with three distal setae on end, median longest.

Males unknown.

Etymology The species name, tenuis (Latin) , alludes to the thin, elongated body with a translucent mantle.

Remarks

Lamprops tenuis sp. nov. is similar to Lamprops beringi ( Calman, 1912) by the presence of one fold on the carapace and by general configuration. However, L. tenuis differs by its considerably smaller size (females are up to 6 mm in length compared to 17 mm for female L. beringi ), by the absence of a subrostral notch (which is rounded and deep in L. beringi ), and by the different position of a fold on the carapace, which does not cross the suture of the frontal field and is directed longitudinally, instead of obliquely as in L. beringi . The most characteristic distinction is the armature of the telson. Lamprops tenuis has five apical teslon spines of which the median spine is considerably shorter than the lateral spines, whereas L. beringi bears five apical spines of which median spine is always the longest.

Figures

FIGURE 1. Lamprops tenuis sp. nov., holotype female, 6.0 mm, ZIN­1/ 88378. A, lateral view; B, carapace, dorsal view; C, telson and uropods. Scale: A = 1.0 mm; B, C = 0.5 mm.

FIGURE 2. Lamprops tenuis sp. nov., holotype female, 6.0 mm, ZIN­1/ 88378. A, pereopod II; B, pereopod III; C, maxilliped III; D, pereopod I. Scale = 0.2 mm.