Lucasioides digitatus Li & Wang, 2024

Wang, Jin, Yao, Chong-Hui, Jiang, Chao & Li, Wei-Chun, 2024, Integrative taxonomy reveals exceptional species diversity of Lucasioides from China (Isopoda: Oniscidea: Agnaridae), Arthropod Systematics & amp; Phylogeny 82, pp. 527-549 : 527-549

3.3. 3. Lucasioides digitatus Li & Wang sp. nov.

Figures 6 D , 9

Type material.

Holotype. CHINA • 1 ♂; Jiangxi Province, Yichun City, Jingan County, Sanzhualun ; 29.0490 ° N, 115.2611 ° E, el. 220 m a. s. l.; 19. vii. 2012; W. C. Li leg. (DNA no. SZL 2002 , Prep. slide nos. L 17309 - L 17314 ) . — Paratypes. • 3 ♀♀; same data as the holotype (DNA nos. SZL 2001 , SZL 2003 and SZL 2004 ) .

Diagnosis.

Cephalon with arched median lobe; pereonite 1 with blunted postero-lateral corner; pleopod 1 exopod with finger-like outer lobe, inner lobe inconspicuous.

Description.

Body length of males 6.2 mm, of females 6.3-8.0 mm. Color in alcohol blackish brown or yellowish brown, dorsum granulated, bearing irregular white muscle spots (Fig. 6 D ). Pereonite 1 sinuous on posterior margin of epimeron, postero-lateral corner blunted. Noduli laterales on pereonites as in Fig. 9 A . Telson triangular, width about one and half times as long as length, lateral margin slightly concave, apex blunted round; uropod exopodite about twice as long as basipodite (Figs 6 D , 9 A ). — Cephalon with arched median lobe, median lobe nearly as long as lateral lobes (Figs 6 D , 9 A ). Antennula with several aesthetascs on distal tip and antero-lateral margins of third article (Fig. 9 B ). Antennal flagellum with second segment twice as long as first one (Fig. 9 C ). — Pereopod 1 with brush of long setae on carpus and merus (Fig. 9 D ). Pereopod 7 ischium with deep depression on rostral surface, carpus slightly expanded near middle on dorsal margin (Fig. 9 E ). — Pleopods 1-5 exopods with Protracheoniscus - type pseudotrachea (Fig. 9 F-J ). — MALE: pleopod 1 exopod slightly concave at posterior margin, outer side with finger-like lobe, inner lobe inconspicuous, endopod with broad basal part, narrowed towards beak-shaped posterior tip (Fig. 9 F ); pleopod 2 endopod styliform, nearly as long as exopod (Fig. 9 G ).

Etymology.

Latin “ digitatus ” = finger-like. The new species name refers to the male pleopod 1 exopod with a finger-like lobe on outer side.

Remarks.

The new species is very similar to L. isseli ( Arcangeli, 1927) in having the cephalon with an arched median lobe, and the first pereonite with a blunted postero-lateral corner. But it can be distinguished in having the pleopod 1 exopod with an undeveloped inner lobe (Fig. 9 F ). In L. isseli , the inner lobe of pleopod 1 exopod is well-developed ( Kwon 1993: fig. 168). In the mounted appendages, this species resembles L. nudus Li, 2017 and L. schmidti sp. nov. Furthermore, the molecular data recognized both species as distinct taxonomic entities (Fig. 5 ).

Figures

Figure 5. Bayesian Consensus tree based on four-gene (COI + 18 S + 28 S + NaK) sequences. Asterisks and circles represent high node support with Bayesian posterior probabilities > 0.95 and maximum bootstrap values > 95. Coloured bars represent hypothesised species groupings.

Figure 6. Habitus of male Lucasioides species in dorsal view. A L. dissectus sp. nov.; B L. isseli (Arcangeli, 1927); C L. dianensis sp. nov.; D L. digitatus sp. nov.; E L. schmidti sp. nov.; F L. nudus Li, 2017; G L. formosus sp. nov.; H L. gracilentus sp. nov.; I L. subcurvatus sp. nov. (Scale: 1 mm).

Figure 9. Lucasioides digitatus sp. nov. A Holotype in dorsal view; B antennula; C antenna; D pereopod 1; E pereopod 7; F pleopod 1; G pleopod 2; H pleopod 3 exopod; I pleopod 4 exopod; J pleopod 5 exopod.