Exalloniscus deharvengi, Taiti & Cardoso, 2020

Exalloniscus deharvengi View in CoL n. sp.

Figures 13, 14, 22E urn:lsid:zoobank.org:act:

Material examined

VIETNAM: Holotype: ♂ ( MNHN), Dong Nai Province, Tan Phu , 11°15’01.7”N 107°24’14.4”E, lava tunnel, on guano, 16.XII.2006, leg. L. Deharveng and A. Bedos. GoogleMaps Paratypes: 1 ♂, 1 ♀ ( MNHN) , 1 ♂, 2 ♀ ♀ ( MZUF), same data as holotype GoogleMaps .

Description

Maximum length: ♂ 3.5 mm; ♀ 4 mm. Body oval, flattened ( Figure 13A); colour brown with pale antennae and uropods ( Figure 22E). Dorsum covered with large triangular scale-setae ( Figure 13B). Cephalon ( Figure 13C,D) with triangular lateral lobes with rounded apices, slightly protruding outwards; frontal line slightly bent down in middle, suprantennal line straight; eyes visible as spots of ocular pigment, without external lenses. Pereonites with postero-lateral corner progressively more acute, directed backwards ( Figure 13E). Pleonites 3-5 with epimera falciform, directed backwards. Telson triangular, wider than long, with slightly concave sides and narrowly rounded apex. Antennula ( Figure 13F) third article with three rows of aesthetascs plus apical pair. Antenna ( Figure 13G) fifth article of peduncle as long as flagellum; ratio of flagellum joints 12:5:5; third article with two aesthetascs. Buccal pieces as in E. schmalfussi n. sp. Pereopods with dactylar seta flagelliform. Pereopod 1 carpus with longitudinal antennal grooming brush ( Figure 14B). Pereopod 7 ( Figure 14C) basis with distinct water conducting system. Uropod ( Figure 14A) exopod as long as endopod.

Male: Pereopod 1 carpus and merus with brush of long setae on sternal margin ( Figure 14B). Pereopod 7 ( Figure 14C) merus, carpus and protopod with some long setae on sternal margin, ischium sternal margin straight. Pleopod 1 ( Figure 14D) exopod triangular, as wide as long, with slightly concave outer margin, posterior point with rounded apex; endopod with distal part slightly bent outward without particular specializations at apex. Pleopod 2 ( Figure 14E) exopod triangular with few setae on the outer margin; endopod flagelliform slightly longer than exopod. Pleopod 3-5 exopods ( Figure 14 F-H) triangular with setae on outer margin.

Etymology

This new species is named after Dr L. Deharveng ( MNHN) for his great contribution to the knowledge of the soil invertebrate fauna of the Oriental Region.

RemarksExalloniscus deharvengi n. sp. is characterized by the wide oval body, brown colour, eyes visible as dots of dark pigment, and male pleopod 1 endopod without particular specializations on the distal part. For this last character, the new species resembles E. vietnamensis Taiti & Ferrara, 1988 View in CoL , and E. caudatus but it differs from both species in having the male pleopod 1 exopod with longer and narrower distal point, and endopod with distal part wider and not pointed; from the former also in the more rounded body shape, pigmented body, and eyes more reduced; from the latter also in having visible eye pigment and wider distal part of the telson.