Lucasioides nudus, Li, Weichun, 2017

Li, Weichun, 2017, A new species of Lucasioides Kwon (Isopoda: Oniscidea: Agnaridae) from China, Zootaxa 4216 (5), pp. 495-500 : 496-497

Lucasioides nudus sp. n.

Type material. Holotype: male, China, Jiangxi Province, Yichun City, Tonggu County (28°32′N, 114°22′E), Xiangutan , ca. 1200 m, 14 September 2011, leg. Weichun Li ( L16032 ).

Paratypes: 4 males, 15 females, same data as the holotype (L201601̄L201619).

Diagnosis. Cephalon with well-developed median lobe ( Fig. 2 C, D). Pereonite 1 with acutely postero-lateral corners and sinuous posterior margin of epimeron ( Fig. 2 D). Male pleopod 1 endopod without setules; exopod distally bilobed, outer lobe much shorter and broader than acute triangular inner lobe ( Fig. 3 K, L).

Description. Maximum body length 7.0 mm. Body elongated (ca. twice as long as wide) ( Fig. 2 A); colour in alcohol dark grey with usual pale muscle spots. Dorsum distinctly granulated. No gland pores. Noduli laterales on pereonites 2̄4 farther from lateral margin than ones on pereonites 1 and 5̄7, b/c and d/c co-ordinates as in Fig. 2 B.

Cephalon ( Fig. 2 C, D) median lobe obtuse triangular, dorsally concave, and protruding upwards in middle; lateral lobes rounded.

Pereonite 1 ( Fig. 2 D) with acutely postero-lateral corners; posterior margin of epimeron sinuous.

Antennula ( Fig. 3 A) with first and second articles almost evenly wide; third article narrowing towards 3 aesthetascs.

Antenna ( Fig. 3 B) with fifth article equipped with 1 seta at distal margin; flagellum with second article approximately twice as long as first article, ending with 1 aesthetasc.

Mandibles ( Fig. 3 C, D) with molar penicil consisting of several plumose setae arising from stem; left mandible with 1 + 2 penicils, right mandible with 1 + 1 penicils.

Maxillula ( Fig. 3 E) with inner lobe bearing 2 stout setulose penicils; outer lobe ending with 3 + 5 teeth of various sizes.

Maxilla ( Fig. 3 F) imperfectly divided into 2 lappets; small lappet suffused with tiny setae near lateral margin at subapical part; apical part of large lappet covered with small setae on outer half.

Maxilliped ( Fig. 3 G) endite subapically with 1 penicil, apical margin sinuous and bearing 3 teeth; palp with 1 well-developed spine and 4 setae.

Telson and uropod ( Fig. 3 H). Telson triangular, lateral margin slightly concave; uropod with short exopod, about twice as long as protopod.

Male. Pereopod 1 ( Fig. 3 I) with brush of long setae on sternal margins of carpus and merus. Pereopod 7 ( Fig. 3 J) ischium with 7 setae on ternal margin, rostral surface with deep depression; carpus not enlarged. Pleopod 1 ( Fig. 3 K, L) endopod with distal part beak-shaped and bent outwards, no setules; exopod ovate, distally bilobed, outer lobe much shorter and broader than inner lobe, inner lobe acute triangular. Pleopod 2 ( Fig. 3 M) endopod styliform, longer than exopod. Pleopod 5 exopod as in Fig. 3 N.

Distribution. China (Jiangxi) ( Fig 1 ).

Etymology. The specific name is derived from the Latin nudus = naked, referring to the male endopod of pleopod 1 without setules.

Remarks. This species is similar to Lucasioides isseli (Arcangeli, 1927) in the general shape and morphology of male pleopod 1. It is distinguished by the pereonite 1 with acutely postero-lateral corners ( Fig. 2 D), the male pleopod 1 endopod being without setules ( Fig. 3 K), the outer lobe of exopod being much broader than the inner lobe ( Fig. 3 L); in L. isseli pereonite 1 is with rounded postero-lateral corners ( Kwon & Taiti 1993: fig. 163), the male pleopod 1 endopod bears setules at the apical part, and the outer lobe of exopod is as broad as the inner lobe ( Kwon & Taiti 1993: fig. 168).

Figures

FIGURE 1. Map of China showing the recorded localities of the genus Lucasioides (L.).

FIGURE 2. Lucasioides nudus sp. n., male paratype. A, adult in dorsal view; B, co-ordinates of noduli laterales; C, cephalon in frontal view; D, cephalon and pereonite 1 in dorsal view.

FIGURE 3. Lucasioides nudus sp. s n., male holotype. A ̅ D, H, dorsal view; E ̅ G, I ̅ N, ventral view; A, antennula; B, antenna; C, left mandible; D, right mandible; E, maxillula; F, maxilla; G, maxilliped; H, telson and uropod; I, pereopod 1; J, pereopod 7; K, pleopod 1 endopod; L, pleopod 1 exopod; M, pleopod 2; N, pleopod 5 exopod.