HYPTIOMINA, Casey, 1906

Li, Liang & Zhou, Hong-Zhang, 2011, Revision and phylogenetic assessment of the rove beetle genus Pseudohesperus Hayashi, with broad reference to the subtribe Philonthina (Coleoptera: Staphylinidae: Staphylinini), Zoological Journal of the Linnean Society 163 (3), pp. 679-722 : 694

THE SUBTRIBE HYPTIOMINA

The subtribe Hyptiomina , which was established by Casey (1906), contains only the genus Holisus Erichson, 1839 distributed in the Neotropical, Nearctic, and Ethiopian regions ( Herman, 2001). Newton & Thayer (1992) treated it as a subtribe of Staphylinini . However, the current systematic position of Hyptiomina in the tribe Staphylinini may still be questionable ( Solodovnikov & Schomann, 2009). In the present phylogenetic analyses, the genus Holisus nested within the core of Philonthina and appeared as Clade C with one branch of the genus Belonuchus (Clade D). This result agreed well with the recent phylogenetic study ( Solodovnikov & Schomann, 2009); although these two studies were based on different sampled representatives and carried out for different purposes. The genus Holisus can be distinguished by a very flat body, aciculate apical segments of labial and maxillary palpi, protibia with ctenidium of several rows of stout setae, mesoscutellum with one transverse carina, and especially the presence of an additional oblique line connecting the superior and inferior lines of the pronotal hypomeron ( Smetana, 1995; Newton et al., 2000). However, it shares most of its character states with the members of the subtribe Philonthina including ligula entire, apical segments of labial and maxillary palpi glabrous, mentum with only one anterolateral seta on each side, neck impunctate, gular sutures fused, claws of all tarsi without empodial setae, and even the additional connecting line of the pronotal hypomeron (similar to that of the genus Craspedomerus , but much longer). It is also easy to understand the close relationships of Holisus and Belonuchus when considering the flat body form and the similar subcortical habitats (most species of Holisus and Belonuchus are found under the bark of decaying trees) ( Solodovnikov & Schomann, 2009). If the broad outlines of this analysis are supported by future work, the subtribe Hyptiomina may suffer the same fate as Craspedomerina (currently treated as a synonym of Philonthina ) in the future.