Stenothemus gemini, Hsiao, Yun, Okushima, Yûichi & Yang, Ping-Shih, 2016

Hsiao, Yun, Okushima, Yûichi & Yang, Ping-Shih, 2016, Review of the genus Stenothemus Bourgeois from Taiwan, with description of three new species (Coleoptera: Cantharidae) and additional distributional records of previously known species, Zootaxa 4117 (1), pp. 101-114 : 111-112

Stenothemus gemini sp. nov.

Figs. 41 , 46–48

Type material. Holotype Ƌ, Litungshan, Hsinchu, Taiwan, 27. X. 2009, S.-F. Yu leg. ( TARI). Paratype: 1 Ƌ, same data as holotype ( TARI).

Description. Male ( Fig. 41 ). Length: 11.00– 13.50 mm (holotype: 13.50); width: 2.75–3.00 mm (holotype: 3.00). Eyes black. Head dark brown, clypeus and vertex orange. Antennae fuscous to black, with each antennomere light brown distally. Mandibles light brown, with apices darker; maxillary and labial palpomeres light yellow. Pronotum dark brown, with anterolateral parts and anterior margin orange and posterior margin light yellow. Scutellum yellowish orange. Elytra yellowish orange; meso-, metaventrites and abdomen orange. Coxae, trochanters, basal halves of femora orange; distal half of femora, tibiae and tarsi dark brown to black. Body densely covered with fine yellowish pubescence; anterior margin of clypeus fringed with pale bristles; antennae, elytra and legs with some yellowish bristles intermingled with primary pubescence, but sparsely at humeri.

Head as long as wide, eyes moderately protruding, ratio of eye diameter to interocular space 1.00:2.15; dorsum slightly swollen on posterior part, depressed along the anterior margin of clypeus and laterally anterior to eyes; anterior margin of clypeus arcuate, slightly emarginate medially; surface densely and finely punctate, each side with a rectangular impression posterior to antennal socket; antennae long, extending to apical third of elytra, antennomere I clavate, II short and expanded apically, III–XI subcylindrical, ratio of antennomere lengths as follows: 18:10:17:21:23:23:23:22:21:18:20.

Pronotum subquadrate, slightly wider than head, about 0.95 times as long as wide; anterior margin slightly arcuate; posterior margin arcuate, but feebly indented medially; lateral margins arcuate, constricted anterior to posterior angles; anterior angles rounded; posterior angles slightly protruding, obtuse; disc swollen, with a pair of rounded elevations posterolaterally; antero-lateral areas hollowed; medio-longitudinal furrow distinct in center of disc; surface matted, finely and sparsely punctate. Scutellum triangular with rounded apex. Elytra collectively about 1.5 times as wide as pronotum, about 3.1 times as long as wide, lateral margins subparallel in basal one-fifth, diverging posteriorly, reaching maximal width at apical fourth; surface densely and coarsely punctate. Prosternal process concave apically. Mesoventrite obviously convex medially. Legs very slender; femora nearly straight; tibiae nearly straight but somewhat bent.

Aedeagus ( Figs. 46–48 ). Ventral process of each paramere clavate, curved inwards apically; dorsal plate of each paramere rounded, expanded apically, longer than ventral process, roundly, widely concave on inner side, with a pair of thin and parallel processes medially; each laterophyse strongly bent dorsad, somewhat pointed apically, laterophyses globular, swollen basally.

Female. Unknown.

Diagnosis. This new species is somewhat similar to S. taiwanus Okushima & M. Satô, 1997 and S. mamorui Okushima & M. Satô, 1999 but can be distinguished by: 1) its completely yellow orange elytra, which is yellowish brown in S. taiwanus and dark brown in S. mamorui ; 2) pronotum of male, which is wider than in S. taiwanus ; and 3) the structure of the aedeagus, especially the dorsal plate with more elongate apex, with paired thin and parallel processes medially on the inner side and less bent laterophyse; however, the apex of dorsal plate is shorter, more rounded in S. taiwanus , paired thin processes medially on the inner side is slightly converging in S. taiwanus and touching apically in S. mamorui ; laterophyse is more bent in S. taiwanus and S. mamorui .

Etymology. The specific epithet is named after the constellation “ Gemini ” which is Latin for “twins”, in reference to the nearly identical appearance between the holotype and paratype.

Distribution. Taiwan (endemic).

Figures

FIGURES 39 – 42. Habitus, dorsal view. 39 – 40. Stenothemus lupus sp. nov.; 41. S. gemini sp. nov.; 42. S. vulpecula sp. nov. Male holotypes: 39, 41 – 42; Female paratypes: 40. Scale bars = 5.0 mm.

FIGURES 43 – 51. Aedeagus. 43 – 45. Stenothemus lupus sp. nov.; 46 – 48. S. gemini sp. nov.; 49 – 51. S. vulpecula sp. nov. Ventral view: 43, 46, 49; Lateral view: 44, 47, 50; Dorsal view: 45, 48, 51. Scale bars: 0.5 mm.