Themus (Themus) dimorphus Y. Yang & X. Yang
Su, Junyan, Li, Limei, Yang, Yuxia & Yang, Xingke, 2015, A new species of Themus (Themus) Motschulsky from Yunnan, China and a redescription of T. (T.) testaceicollis Wittmer, 1983 (Coleoptera, Cantharidae), ZooKeys 525, pp. 107-116: 108
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|Themus (Themus) dimorphus Y. Yang & X. Yang|
Taxon classification Animalia Coleoptera Cantharidae
Themus (Themus) dimorphus Y. Yang & X. Yang sp. n. Figs 1 A–B, 2 A–C, G, 3
Holotype, male (MHBU): CHINA: Yunnan, Yiliang, Xiaocaoba, 25.VIII.2013, leg. Xun Bian & Guang-Lin Xie; Paratypes: 2 males (MHBU): same data to the holotype; 2 females (MHBU): same locality and collectors, 24.VIII.2013.
Male (Fig. 1A). Head metallic dark blue and weakly shining, lateral parts of clypeus yellow, mouthparts yellow, maxillary and labial palpi and apices of mandibles dark brown; prothorax yellow, pronotum with a moderately large, irregular black marking in center of disc, antennae black, antennomeres I–III yellow on ventral sides, scutellum black, elytra metallic green and weakly shining, legs and meso- and metasterna metallic dark blue and weakly shining, abdomen yellow, slightly darkened on both sides of ventrites I–V. Body densely covered with decumbent brown pubescence, mixed with slightly long semierect pubescence on elytra and a few long hairs along anterior margin of clypeus.
Head rounded, densely and finely punctate, surface lustrous; eyes slightly protruding, breadth across eyes slightly wider than anterior margin of pronotum; terminal maxillary palpomeres widest nearly in middle, arcuate and sharp at apical parts of inner margins, rounded at apices; antennae extending to basal two-fifth length of elytra, antennomeres II approximately twice as long as wide at apices, III–X slightly obliquely widened apicad, III approximately twice as long as wide at apices and 1.5 times as long as II, IV approximately 1.5 times as long as III, IV–XI subequal in length, each with a small round to short narrow longitudinal impression in middle or basal part of outer margin, XI pointed at apices.
Pronotum approximately 1.40 times as wide as long, widest near base, anterior margin arcuate, lateral margins slightly sinuate at anterior part and distinctly diverging posteriorly, posterior margin bisinuate and narrowly bordered, anterior angles rounded, posterior angles nearly rectangular, disc slightly convex at posterolateral parts, surface lustrous, slightly finely and sparsely punctate than that on head.
Elytra approximately 3.0 times longer than pronotum, 2.6 times longer than humeral width, lateral margins distinctly converging posteriorly, apex of each elytron rounded, disc rugulose-lacunose and coarsely punctate, surface matt.
Aedeagus (Fig. 2 A–C): ventral process of each paramere narrow and straight, rounded at apex; conjoint dorsal plate of parameres slightly shorter than ventral processes, largely subroundly emarginated in middle of apical margin, with lateroapical angles acute and bent ventrally; laterophyses widely separated on both sides of median lobe, with apices acute and pointed dorsally to lateroapical angles of conjoint dorsal plate.
Female (Fig. 1B). Similar to male, but clypeus uniformly yellow; antennae narrower and shorter, extending to basal one-fifth length of elytra; antennomeres III nearly as long as II, IV‒XI without impressions, XI slightly longer than X; pronotum without any black marking (one specimens with two indistinct small dark brown markings on both sides of disc); elytra approximately 2.5 times longer than humeral width, with lateral margins slightly converging posteriorly; scutellum sometimes yellow (one specimen). Abdominal sternite VIII (Fig. 2G) moderately triangularly emarginated in middle and indistinctly emarginated on both sides of posterior margin. Internal reproductive organ of genitalia (Fig. 3): vagina stout, abruptly narrowed into a short tube at apical part of ventral side, below which present with a pair of strongly sclerotized, arcuate and conjoint ridges extending to median oviduct; diverticulum and spermatheca arising from the end of the short tube of vagina; diverticulum very short and rounded at apex; spermatheca sac-shaped and rounded at apex, distinctly expanded apicad and bent in middle, provided with a moderately long and thin accessory gland at base.
Body length: 8.0‒11.0 mm; width: 3.0‒4.5 mm.
The specific name is derived from Latin dimorphus (dimorphic), referring to its different coloration of head and pronotum in both sexes.
The new species can be distinguished from most of the species of Themus (Themus) Motschulsky by the smaller body and uniformly orange pronotum or at most with one or two small black markings, which characters also equipped by the following species in the key.
A key to Themus (Themus) dimorphus sp. n. and its similar species
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