Hemilepistus (Desertellio) gracilentus Li & Jiang, 2023

Wang, Jin, Hong, Xinkai, Jiang, Chao & Li, Weichun, 2023, First record of the subgenus Hemilepistus (Desertellio) (Isopoda, Agnaridae) from China, Zootaxa 5389 (3), pp. 362-372 : 365-366

Hemilepistus (Desertellio) gracilentus Li & Jiang sp. nov.

http://zoobank.org:act: 39925F37-EF4F-4F62-865E-BF03E2E715FC

Figs 2−3

Material examined: Holotype male, CHINA: Xinjiang Uygur Autonomous Region, Wujiaqu (44.1665°N, 87.5429°E), suburbs of Wujiaqu City , 7.vi.2022, leg. Guodong Shang, prep. slide nos. L23001, accession no. LC764593 [deposited in the Insect Museum, Jiangxi Agricultural University, Nanchang, China ( JXAUM)] . Paratypes: one female, same collection data as holotype [deposited in National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China ( CMMI)] ; seven males, three females, same collection data as holotype except collection date 24.iv.2023 (two males and two females deposited in JXAUM, five males and one female deposited in CMMI) .

Diagnosis: Pereonites 1–2 with four tubercles near middle part, and first pleopod endopodite of male individual with an apical inner lobe surpassing well the summit of endopodite bearing seven small spines.

Description: Body thin and long, 3.5 times as long as greatest width. Colour dark brown, but tubercles, epimera, pereopods, posterior margin of each pereonite and pleonite white. Head with tiny tubercles, lateral lobe small triangular, median lobe absent. Eyes with 24–25 ommatidia. Pereonites 1–2 with four tubercles near middle part; pereonites 3–7 smooth in males; pereonites 3 with two tiny tubercles near the middle part in females. Pleon short and smooth, narrower than pereon. Telson triangular, approximately twice as wide as long, lateral margin slightly concave, apex pointed.

Antennula composed of three articles, distal article bearing a cluster of small aesthetascs. Antenna reaches posterior part of pereonite 2 when extended backwards, fifth article of peduncle and flagellum equipped with long setae, flagellum with first segment slightly longer than second one.

Pereopods 1 and 7 without sexual dimorphism. both equipped with several strong spines on ventral margin and distal tip of merus and carpus.

Pleopods 1 and 2 exopodites with well-developed monospiracular internal lungs; pleopods 3–5 exopodites with small lungs. Male pleopod 1 exopodite with shore acute hind margin; endopodite with broad basal part, narrowed towards apical tip, apex with a finger-like inner lobe equipped with seven small spines, surpassing apex of endopodite; male pleopod 2 endopodite nearly as long as exopodite, distal article thin and long.

Uropods protopod with conspicuous incision on lateral margin, exopod short and conical, slightly longer than protopod and telson.

Size: 13–26 mm.

Remarks: This new species is similar to H. (D.) pavlovskii Borutzky, 1954 by the male pleopod 1 endopodite with a finger-like inner lobe at apex goes beyond the apex, but it can be distinguished from the latter by the following characters: the head with small triangular lateral lobe, median lobe absent; pereonites 1–2 with four tubercles near middle; uropods exopod slightly longer than telson ( Fig. 2 ). In H. (D.) pavlovskii , the median lobe is well-developed, the lateral lobes are quadrangular, pereonites 1–2 without tubercles, uropods exopod four times as long as telson ( Kashani 2019: fig. 4A–B; fig. 5A, C).

Etymology: The specific name is derived from the Latin gracilentus = thin and long, in reference to the species with a thin and long body.

Figures

FIGURE 2. Hemilepistus (D.) gracilentus sp. nov., male, holotype. A, habitus in dorsal view; B, head in dorsal view; C, head in frontal view; D, head and pereonites 1−3 in dorsal view. Scale bars: 1 mm.

FIGURE 3. Hemilepistus (D.) gracilentus sp. nov., male, holotype.A, antennula; B, antenna; C, pereopod 1; D, pereopod 7; E, pleopod 1 exopodite; F, pleopod 1 endopodite and enlarged apex; G, pleopod 2; H, pleopod 3 exopodite; I, pleopod 4 exopodite; J, pleopod 5 exopodite. Scale bars: 0.5 mm except for figure A with 0.1mm.