Five new species of Exalloniscus Stebbing, 1911 (Crustacea, Isopoda, Oniscidea) from China Author Jiang, Chao https://orcid.org/0000-0003-1841-1169 State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China Author Yao, Chonghui College of Agronomy, Jiangxi Agricultural University, Nanchang 330045, China Author Huang, Luqi State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China Author Li, Weichun https://orcid.org/0000-0003-0154-861X College of Agronomy, Jiangxi Agricultural University, Nanchang 330045, China weichunlee@126.com text Zoosystematics and Evolution 2024 2024-04-03 100 2 373 383 http://dx.doi.org/10.3897/zse.100.115813 journal article http://dx.doi.org/10.3897/zse.100.115813 1860-0743-2-373 1B0AF998E43A4F829F97F6F8C99133B4 5D2E69C833D9547DA4F98318B78C2474 Exalloniscus tridentatus Li & Jiang sp. nov. Figs 1F , 6 Type material. Holotype . China : male, Shaanxi Province, Zhashui County, Dongshan Forestry Park ( 33°42'N , 109°01'E ), alt. 1020 m, 12 May 2021, Chao Jiang leg., habitus no. ZS2301, prep. slide no. L23095 (JXAUM). Paratypes . China : two males, two females, same data as the holotype, nos. 20210512007-20210512009 (CMMI). Diagnosis. Male pleopod 1 exopod straight on outer margin, and endopod bearing three well-developed dentations at apical part. Description. Maximum length: male 2.5 mm and female 2.8 mm. Body oval, slightly convex. Colour white mixed with 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. 1F ). Antenna with fifth article of peduncle slightly longer than flagellum; ratio of flagellum approximately 3:2:2 (Fig. 6A ). Figure 6. Exalloniscus tridentatus 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. Pereopod 1 with long strong setae on sternal margin of merus and carpus (Fig. 6B ). Pereopod 7 with several strong setae on sternal margin; basis without water conducting system; ischium almost straight on sternal margin (Fig. 6C ). Male pleopod 1 exopod oval, straight on outer margin; endopod with apical portion bearing rounded hyaline lobe and three well-developed dentations (Fig. 6D ). Pleopod 2 exopod triangular; endopod flagelliform, longer than exopod (Fig. 6E ). Pleopods 3-5 nearly triangular with several setae on outer margin (Fig. 6F-H ). Etymology. Latin: Exalloniscus tridentatus = trident. The new species name refers to the male pleopod 1 endopod with three dentations at apical portion. Remarks. This new species is similar to E. cortii Arcangeli, 1927 by body shape and male pleopod 1 endopod bearing a rounded hyaline lobe at the apical portion (Figs 1F , 6D versus Figs 1G , 7D ). But it can be distinguished by pereopod 7 basis without water conducting system, pleopod 1 exopod straight on the outer margin, and endopod bearing three well-developed dentations at the apical portion (Fig. 6C, D ). In E. cortii , pereopod 7 basis has a well-developed water conducting system, pleopod 1 exopod is sinuous on the outer margin, and endopod with two spinelike projections at the apical apex (Fig. 7C, D ). Figure 7. Exalloniscus cortii (one male, China, Hunan Province, Yongzhou, Puliqiao Town, 21 March 2019, Chao Jiang leg., prep. slide no. L23099). 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.