Exalloniscus taitii Li & Jiang, 2024

Jiang, Chao, Yao, Chonghui, Huang, Luqi & Li, Weichun, 2024, Five new species of Exalloniscus Stebbing, 1911 (Crustacea, Isopoda, Oniscidea) from China, Zoosystematics and Evolution 100 (2), pp. 373-383 : 373

Exalloniscus taitii Li & Jiang sp. nov.

Figs 1H , 8

Type material.

Holotype. China: male, Yunnan Province, Gengma County, Daxing Village (23°45'N, 99°46'E), alt. 2270 m, 29 May 2021, Chao Jiang leg., habitus no. DXX2302, prep. slide no. L23100 (JXAUM).

Diagnosis.

Male pleopod 1 endopod conspicuously concave near middle of outer margin and bearing a tiny spine at apical part of inner margin, pleopods 3 concave on outer margin.

Description.

Length 2.0 mm.

Body oval, slightly convex. Colour pale brown. Cephalon with lateral lobes slightly protruding laterally, apex rounded. Eyes with three ommatidia. Pereonites with postero-lateral corners directed backwards. Pleonites 3-5 with epimera falciform, protruding backwards. Telson triangular, twice as wide as long, lateral margin slightly concave, apex rounded. Uropod exopod approximately twice as long as endopod (Fig. 1H ).

Antenna with fifth article of peduncle slightly shorter than flagellum; ratio of flagellum approximately 3:3:4 (Fig. 8A ).

Pereopod 1 with long strong setae on sternal margin of merus and carpus, carpus without transversal antennal grooming brush (Fig. 8B ). Pereopod 7 with several strong setae on sternal margin; basis without water conducting system; ischium almost straight on sternal margin (Fig. 8C ).

Male pleopod 1 exopod base narrow, distinctly broaden towards apical part, almost straight on outer margin; endopod base broad, narrowed towards point apex, outer margin conspicuously concave near middle, apical part with tiny spine on inner margin (Fig. 8D ). Pleopod 2 exopod triangular, outer margin concave; endopod flagelliform, longer than exopod (Fig. 8E ). Pleopods 3-5 nearly triangular, pleopods 3 concave on outer margin, pleopods 4-5 almost straight on outer margin (Fig. 8F-H ).

Etymology.

The new species name honors Dr. Stefano Taiti for his invaluable contribution to the taxonomy of terrestrial isopods.

Remarks.

This new species is similar to E. burmaensis Taiti & Cardoso, 2020 by the traits of male pleopod 1. But it can be distinguished by the ratio of flagellum approximately 3:3:4; pereopod 1 carpus without transversal antennal grooming brush, and pereopod 7 basis without water conducting system; pleopod 1 endopod conspicuously concave near the middle of the outer margin, and bearing a tiny spine at the apical part of the inner margin, pleopods 3 concave on the outer margin (Fig. 8A-D, F ). In E. burmaensis , flagellum is diminishing in length from the first segment to the third segment; pereopod 1 carpus with a transversal antennal grooming brush, and pereopod 7 basis has a well-developed water conducting system; pleopod 1 endopod is almost straight on the outer margin, and the apical part without spine on the inner margin, pleopods 3 is straight on the outer margin ( Taiti and Cardoso 2020: Fig. 17H, 18B-D, F).

Figures

Figure 1. Habitus of Exalloniscus species. A. E. duospinatus sp. nov., holotype; B (holotype); C (paratype). E. curvispinatus sp. nov.; D. E. thailandensis, male; E. E. triangulus sp. nov., holotype; F. E. tridentatus sp. nov., holotype; G. E. cortii, male; H. E. taitii sp. nov., holotype. Scale bar: 1 mm.

Figure 8. Exalloniscus taitii sp. nov., holotype. A. Antenna; B. Pereopod 1; C. Pereopod 7; D. Pleopod 1; E. Pleopod 2; F. Pleopod 3 exopod; G. Pleopod 4 exopod; H. Pleopod 5 exopod. Scale bar: 0.1 mm.