Lucasioides formosus 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. 5. Lucasioides formosus Li & Wang sp. nov.

Figures 6 G , 11

Type material.

Holotype. CHINA • 1 ♂; Yunnan Province, Lijiang City, Yulong County, Liming Lisu Ethnic Township, Houka ; 27.1469 ° N, 99.8193 ° E, el. 1921 m a. s. l.; 8. vii. 2022; J. Wang, X. K. Hong leg. (DNA no. HK 2201 , Prep. slide no. L 22081 ) . — Paratypes. • 2 ♂♂, 2 ♀♀; same data as the holotype (DNA nos. HK 2202 - HK 2205 ) . CHINA • 1 ♂, 4 ♀♀; Yunnan Province, Lijiang City, Zimei lake ; 26.9891 ° N, 100.1966 ° E, el. 2724 m a. s. l.; 7. vii. 2022; J. Wang, X. K. Hong leg. (DNA nos. ZMH 2201 - ZMH 2205 , Prep. slide no. L 22082 ) . • 2 ♂♂, 4 ♀♀; Yunnan Province, Dali City, Jianchuan County, Qianshi Mountain ; 26.5328 ° N, 99.8877 ° E, el. 2364 m a. s. l.; 11. vii. 2022; J. Wang, X. K. Hong leg. (DNA nos. QSS 2201 - QSS 2206 , Prep. slide no. L 22076 ) . • 4 ♀♀; Yunnan Province, Lijiang City, Gucheng District ; 26.9258 ° N, 100.2079 ° E, el. 2465 m a. s. l.; 7. vii. 2022; J. Wang, X. K. Hong leg. (DNA nos. LJGC 2201 - LJGC 2204 ) . • 3 ♀♀; Yunnan Province, Lijiang City, Meiquan Village ; 26.9058 ° N, 100.1499 ° E, el. 2486 m a. s. l.; 6. vii. 2022; J. Wang, X. K. Hong leg. (DNA nos. MQC 2201 - MQC 22032205 ) .

Diagnosis.

Pereonite 1 slightly sinuous on posterior margin of epimeron, postero-lateral corner nearly right-angled; noduli laterales on pereonites 1-4 shifted from lateral margins than those of pereonites 5-7; pereopod 7 remarkably expanded on dorsal margin of carpus; pleopod 1 exopod slightly concave at posterior tip.

Description.

Body length of males 6.3-8.0 mm, of females 5.5-11.0 mm. Color in alcohol blackish brown, dorsum granulated, bearing irregular yellowish white muscle spots (living individuals with yellowish blue muscle spots). Pereonite 1 slightly sinuous on posterior margin of epimeron, postero-lateral corner nearly right-angled (Fig. 6 G ). Noduli laterales on pereonites 1-4 shifted from lateral margins than those of pereonites 5-7 (Fig. 11 A ). Telson triangular, width about twice as long as length, lateral margin slightly concave, apex blunted; uropod exopodite about three times as long as basipodite (Figs 6 G , 11 A ). — Cephalon with arched median lobe, median lobe longer than lateral lobes (Figs 6 G , 11 A ). Antennula with several aesthetascs on distal tip of third article (Fig. 11 B ). Antennal flagellum with second segment twice as long as first one (Fig. 11 C ). — Pereopod 1 with brush of long setae on carpus and merus (Fig. 11 D ). Pereopod 7 ischium without deep depression on rostral surface, carpus remarkably expanded near middle on dorsal margin (Fig. 11 E ). — Pleopods 1-5 exopods with Protracheoniscus - type pseudotrachea (Fig. 11 F-J ). — MALE: pleopods 1 exopod slightly concave at posterior tip, forming two inconspicuous lobes, endopod with broad basal part, narrowed towards apex, posterior tip beak-shaped and bent outwards (Fig. 11 F ); pleopod 2 exopoddistinctive concave on outer margin, posterior two fifths with several setae, endopod styliform, slightly longer than exopod (Fig. 11 G ).

Etymology.

Latin “ formosus ” = beautiful. The new species name is an allusion to beautiful yellowish blue muscle spots on the dorsum of the living individuals.

Remarks.

The new species is not strictly consistent with the generic characters of Lucasioides because of the noduli laterales on pereonites 1-4 shifted from lateral margins than those of pereonites 5-7 instead of the noduli laterales on pereonites 2-4 much farther from lateral margins than those of pereonites 1, 5-7. It is difficult to give a ready answer for this dilemma based on the morphological evidence alone. In the phylogenetic analyses, the relationship between this species and the other Lucasioides species is well-supported (Fig. 5 ). Hence, we assigned this species as a member of Lucasioides by integrating molecular and morphological evidence in this context.

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 11. Lucasioides formosus 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.