Siamites complicatus, Jałoszyński, Paweł, 2013

Jałoszyński, Paweł, 2013, A new species of Siamites Franz (Coleoptera, Staphylinidae, Scydmaeninae) from Thailand, Zootaxa 3734 (3), pp. 385-390 : 386

Siamites Franz

Siamites Franz, 1989: 44 . Type species: Siamites loebli Franz, 1989 (original designation).

The new species, although shares with S. loebli a number of taxonomically important characters, differs in the lateral pronotal margins, which in S. loebli are rounded, while in S. complicatus sp. n. indistinctly carinate in the posterior half. As recently found in the Australian genus Scydmaenilla , the lateral pronotal margins may show some degree of variability and within one genus may be rounded, indistinctly or distinctly carinate (Jałoszyński 2013). This character may depend on how convex or flattened the pronotum is, and at least in Scydmaenilla it does not correlate with any other characters. The same seems true for Siamites ; besides the pronotal edges, both species differ only in minor characters, as the body silhouette and genital structures.

Revised diagnosis. Siamites can be distinguished from all other genera of Cyrtoscydmini by the following combination of characters: antenna with indistinctly separated club composed of three antennomeres; vertex flattened or impressed; submentum subtriangular, strongly narrowing caudad, demarcated from post-cardinal parts of hypostoma; posterior tentorial pits visible in ventral view; prothorax subconical, with lateral pronotal margins rounded or indistinctly carinate in posterior half, with pronotal ante-basal transverse groove connected at each side to shallow and small pit; procoxal cavities separated in middle by low and narrow carina; prothoracic hypomera with incomplete hypomeral ridges; mesoventral intercoxal process narrow and keel-shaped but only moderately expanding ventrad; metaventral intercoxal process narrow so that metacoxae are nearly adjacent in middle; each elytron with single and asetose basal fovea, indistinct humeral carina and small humeral denticle; body with dense bunches, rosettes or semi-rosettes of bristles distributed across vertex, along anterior margin of prosternum, across mesoventrite, along posterior margins of mesocoxal cavities and along posterior margin of abdominal sternites; aedeagus with free parameres.