Exalloniscus kampucheaensis, Taiti & Cardoso, 2020

Exalloniscus kampucheaensis View in CoL n. sp.

Figures 9, 10, 22C

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Material examined

CAMBODIA: Holotype: ♂ ( MNHN), Kampot, Tuk Meas, Phnom Teng Ngai, “Grotte Sauna”, cave, 22.XI.2005, leg. L. Deharveng and A. Bedos. Paratype: 1 ♀ ( MNHN), same data as holotype .

Description

Length: ♂ 3.5 mm; ♀ 2.5 mm. Body oval, flattened ( Figure 9A); colour pale ( Figure 22C). Dorsum covered with large rounded scale-setae ( Figure 9B). Cephalon ( Figure 9C,D) with lateral lobes triangular with rounded apices, slightly protruding laterally; frontal line slightly bent down in middle, suprantennal line straight; eyes with three ommatidia. Pereonites 1-3 with postero-lateral corners right-angled, pereonites 4-7 with postero-lateral corners progressively more acute, directed backwards ( Figure 9E). Pleonites 3-5 with epimera falciform, protruding backwards. Telson triangular, wider than long, with slightly concave sides and acute apex. Antennula ( Figure 9F) third article with two rows of aesthetascs plus apical pair. Antenna ( Figure 9G) with fifth article of peduncle as long as flagellum; ratio of flagellum joints 10:5:6; one aesthetasc on second and two aesthetascs on third flagellar article. Buccal pieces as in E. schmalfussi n. sp. Pereopods with dactylar seta flagelliform. Pereopod 1 carpus with transversal antennal grooming brush ( Figure 10B). Pereopod 7 ( Figure 10C) basis with distinct water conducting system. Uropod ( Figure 10A) exopod slightly longer than endopod.

Male: Pereopods 1-3 carpus and merus with brush of long setae on sternal margin ( Figure 10B). Pereopod 7 ( Figure 10C) merus, carpus and propodus with some long setae on sternal margin, ischium with sternal margin slightly concave. Pleopod 1 ( Figure 10D) exopod triangular, wider than long, outer margin almost straight, posterior point widely rounded; endopod thickset, with triangular distal part. Pleopod 2 ( Figure 10E) exopod triangular with few setae on outer margin; endopod flagelliform, longer than exopod. Pleopod 3-5 exopods ( Figure 10 F-H) triangular with few setae on outer margin.

Etymology

The new species is named for Kampuchea, the Khmer name of Cambodia, where the species was collected.

Remarks

The new species is characterized by pale colour, presence of eyes, male pereopod 7 ischium with sternal margin slightly concave, male pleopod 1 exopod short, triangular, with posterior point largely rounded, and endopod with triangular distal part. Exalloniscus kampucheaensis n. sp. resembles E. caudatus in the similar shape of the male pleopod 1 endopod, but it differs in the presence of eyes, telson with a wider distal part, male pleopod 1 exopod with outer margin less concave, and male pleopod 2 exopod with only a few setae on distal part of outer margin (compare figs 20, 21 in Taiti and Ferrara 1988).