Exalloniscus tortilis, Taiti & Cardoso, 2020

Exalloniscus tortilis View in CoL n. sp.

Figures 11, 12, 22D

urn:lsid:zoobank.org:act:

Material examined

VIETNAM: Holotype: ♂ ( MNHN), Yen Bai Province, Nghia Lo, Xa Som, Tham Han , 21°38’52.7”N 104°31’11.2”E, cave, 20.XII.2003, leg. L. Deharveng and A. Bedos. GoogleMaps Paratypes: 1 ♂, 3 ♀♀ ( MNHN) , 1 ♂, 3 ♀♀ ( MZUF), same data as holotype GoogleMaps ; 2 ♀♀ ( MNHN), Yen Bai Province, Nghia Lo, Hang Dan Khao , 21°39’21.1”N 104°31’39.2”E, cave, 20.XII.2003, leg. L. Deharveng and A. Bedos. GoogleMaps

Description

Maximum length: ♂ and ♀ 4.5 mm. Body oval, flattened ( Figure 11A): colourless, ( Figure 22D). Dorsum with scattered short triangular scale-setae ( Figure 11B). Cephalon ( Figure 11C,D) with lateral lobes triangular with rounded apices, slightly protruding laterally; frontal line almost straight, suprantennal line bent in middle; eyes absent. Pereonites with postero-lateral corners progressively more directed backwards ( Figure 11E). Pleonites 3-5 with epimera falciform, directed backwards. Telson triangular, wider than long, with slightly concave sides and rounded apex. Antennula ( Figure 11F) third article with two rows of aesthetascs plus apical pair. Antenna ( Figure 11G) fifth article of peduncle as long as flagellum; ratio of flagellum joints 9:6:7; second flagellar article with two rows of three and two aesthetascs, third article with one row of four aesthetascs. Buccal pieces as in E. schmalfussi n. sp. Pereopods with very long flagelliform dactylar seta. Pereopod 1 carpus with transversal antennal grooming brush ( Figure 12B). Pereopod 7 ( Figure 12C) basis with distinct water conducting system. Uropod ( Figure 12A) exopod distinctly longer than endopod, twice as long as protopod.

Male: Pereopod 1 carpus and merus with long setae on sternal margin ( Figure 12B). Pereopod 7 ( Figure 12C) ischium with slightly convex sternal margin. Pleopod 1 ( Figure 12D) exopod triangular, wider than long, with outer margin concave, posterior point short with rounded apex; endopod with distal part twisted, slightly bent outward. Pleopod 2 ( Figure 12E) exopod triangular with few setae on outer margin; endopod flagelliform, longer than exopod. Pleopod 3-5 exopods ( Figure 12 F-H) triangular with few setae on outer margin.

Etymology

Latin: tortilis = twisted. The species name refers to the twisted shape of the distal part of the male pleopod 1 endopod.

RemarksExalloniscus tortilis n. sp. is easily distinguished from all the other species by the shape of male pleopod 1 endopod, with distal part twisted and slightly bent outward. A similar character is present also in E. papillosus (compare fig. 5D in Taiti and Ferrara 1988) from which the new species differs in having colourless body, lack of eyes, and different shape of the male pleopod 1 exopod. The new species was collected only in caves.