Discussion, Reitter, 1882

Yin, Zi-Wei, Kurbatov, Sergey A. & Ку, A., 2022, Schmidtinus annapurnensis, a new genus and species of Batrisitae from Nepal (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 5169 (1), pp. 79-86 : 84

Discussion

Schmidtinus gen. nov. is morphologically similar to a number of East Asian genera that are known or putative inquilines of Lasius ants, i.e., Songius , Tangius , and Dendrolasiophilus . These genera share a similar general structure of the aedeagus, and may form a monophyletic group within Asian Batrisini . They can be separated by using the following key:

1 Head strongly transverse; each elytron with one basal fovea........................ Dendrolasiophilus Nomura, 2010

- Head almost as long as to slightly longer than wide; each elytron with three basal foveae............................ 2

2 Sides of tergite 1 (IV) clearly convergent from middle toward base, so base of tergite distinctly..narrower than elytra in their widest part; tergite 1 in dorsal view markedly longer than 2 (V) and 3 (VI) combined............ Tangius Yin & Li, 2012

- Sides of tergite 1 (IV) broadest at or near base, base of tergite of equal width with or slightly..... broader than elytra at their widest part; tergite 1 (IV) in dorsal view as long as or shorter than 2 (V) and 3 (VI) combined........................ 3

3 Vertical heights of postocular margins clearly longer than those of eyes; pronotum trapezoidal, broadest at basal 1/3; elytra lacking discal stria; habitus typically stouter............................................. Songius Yin & Li, 2010

- Vertical heights of postocular margins shorter than those of eyes; pronotum roundly explanate laterally, broadest near middle; elytra with discal stria; habitus more elongate............................................. Schmidtinus gen. nov.

In addition, the new genus differs from Songius also by a different pattern of male sexual characters, i.e., modified antennae, protibiae, and posterior margin of the metaventrite, which have never been observed in the latter genus. More specifically, all Songius species have the aedeagus with a more-or-less serrate apical margin of the dorsal lobe, and there is a short apophysis on the lateral margin of the ventral stalk, both of which are lacking in Schmidtinus gen. nov. Tangius contains two Himalayan species from Tibet ( China) and northern India ( Yin & Li 2013b); Songius consists of four species from Zhejiang, Hunan, Guanxi, and was shown to inhabit a much broader distributional range in China ( Yin & Li 2015); and Dendrolasiophilus is represented by four species from Far East Russia, Japan, and China ( Nomura 2008, 2010; Yin & Li 2013a; Kurbatov & Kovalev 2022). All members of the latter three genera variably possess a suite of ‘reductive’ ( Parker & Owens 2018; Yin 2018) morphological traits such as a smooth and glabrous appearance, moniliform antennomeres, a reduced number of foveae, carinae and sulcus on the body surface, and have developed gland-associated trichomes at the posterior corners of the head. Some of these characters are found in Schmidtinus gen. nov., which suggests that it can be likewise a myrmecophilic genus. Almost each species of this group is represented by such few specimens in collections that continuing field efforts are needed to further explore the biology and evolutionary history of these beetles.

There are a few other recently described batrisine genera from East Asia that host different ant genera and show morphological peculiarities related to myrmecophily, e.g., Pengzhongiella Yin & Li (Odontomachus) , Lisubatrus Yin , Loeblibatrus Yin (Ectomomyrmex) , and Myrmicophila Yin & Li (Myrmica) ( Yin & Li 2013c; Yin 2017, 2018, 2021; Yin et al. 2011; Zhang & Yin 2022). They are morphologically distinct from the Dendrolasiophilus group and may have separately evolved in accordance with the post-Cretaceous diversification (Moreau et al. 2016) of modern ants.