Pretarsal structures in Leiodidae and Agyrtidae (Coleoptera, Staphylinoidea)

Abstract

We analysed pretarsal characters of 87 species of Leiodidae (including 10 cholevines and representatives of all tribes and ca. 60% of the genera of non-cholevines), five species of Agyrtidae, and nine representatives of outgroup taxa (Hydraenidae, Staphylinidae, Hydrophilidae, and Histeridae) using scanning electron microscopy. We focused our observations on the architecture of the empodium (including the sclerites and associated setae), the shape and composition of the medial projection of the distal margin of the terminal tarsomere, and the armature of the claws, which were considered a promising source of information for delimiting supraspecific taxa in our previous study. We identified several diagnostic features and recognize potential synapomorphies at the tribal, subtribal and generic levels. The internal systematic arrangement and/or even the monophyletic status of most of the subfamilies of Leiodidae (Camiarinae, Catopocerinae, Leiodinae, and Platypsyllinae) are challenged. We identified potential synapomorphies for Camiarinae (Camiarini and Agyrtodini) and Leiodinae. The non-monophyly of Cholevinae is possible because part of the tribe (Anemadini, Eucatopini, and Oritocatopini) shares potentially apomorphic features with Leiodinae (e.g., a triangular medial projection with a diagonal row of conical spines), whereas another part (Leptodirini and Ptomaphagini) shares a potentially apomorphic feature with Coloninae and Platypsyllinae (a typical medial projection with two distinct triangular projections).

To be or not to be a tibial comb: A discussion on the (past) use of tibial armature in tribal/subtribal organization in Cholevinae (Coleoptera: Leiodidae)

“…For comparison, we examined additional taxa, namely, Anemadini: Anemadina and Eunemadina, Cholevini: Catopina, Leptodirini: Table 1. List of species of Leiodidae Cholevinae examined in this study [¹ specimens used in Antunes-Carvalho & Gnaspini (2016); ² specimens used in Gnaspini et al (2017a); ³ specimens used in Antunes-Carvalho et al (2019); ⁴ images from M. Perreau (either in Perreau, 2000 or unpublished)], with a summary of the main morphological characteristics observed on the mesotibial apex among the studied taxa. TC denotes if mesotibiae have ('Y' (yes) [or '~Y' if it bears small differences from that in Ptomaphagini]) or not ('N' (no), although a series of spines may be present) an apical crown of spines; IN denotes the number of 'interstitial spines' .…”

To be biased or to be Neotropical: systematic reassessment of a megadiverse lineage of rove‐beetles (Philonthina, Staphylinini, Staphylininae)

“…Note: Herein we introduce the term “discal setae” for those modified setae sometimes present in Coleoptera on the ventral surface of (mostly) protarsomeres and traditionally called “adhesive” or “tenent setae” (see Stork, and Gnaspini et al., , for further references). We aim to differentiate them from the “marginal setae” (see below) as nonhomologous structures.…”

“…diamantinus, one of the most enigmatic clades of the NT lineage due to their widened protarsomeres with discal setae on the ventral side--the socalled "tenent" or "adhesive" setae of previous authors (e.g. Stork, 1980;Gnaspini et al, 2017aGnaspini et al, , 2017b; (iv) the Paederomimus group 3, here resolved as the clade containing the type species of the genus; and (v) the Musicoderus clade, which appears well supported and phylogenetically distant from the "true Belonuchus", and was recovered within a more inclusive clade, which is referred to here as the "Paederomimus complex". As already acknowledged, we are aware of restrictions imposed by our taxon sampling, so we are cautious about proposing broader limits or sistergroup relationships for any of these groups other than those already discussed above.…”

“…The configuration of protarsi involves two independent but associated characters that occur in and out of Philonthina (e.g. Chani‐Posse, ; Gnaspini et al., , ): the expansion, dilatation or width of protarsomeres and the presence/absence of modified adhesive setae on their ventral surface. These characters and their states have proved to be useful for defining natural groups not only within Philonthina (e.g.…”

The Near Eastern species of Leptodirini (Coleoptera: Leiodidae: Cholevinae)

“…Most genera of Leptodirini (including all other genera of the Near East) have two interongular empodial setae (Figure 16). Species which have a single empodial developed seta belong to the genus Platycholeus Horn, 1880 (Newton 1998;Gnaspini et al 2017) in subtribe Platycholeina, and some French genera such as Diaprysius Abeille de Perrin, 1878 (Gnaspini et al 2017), Speonomus Jeannel, 1908(Perreau 2000Antunes-Carvalho & Gnaspini 2015) and Troglocharinus Reitter, 1908(Antunes-Carvalho & Gnaspini 2015, within Pholeuina, but whose distribution areas are far remote from Turkey. When a single developed seta occurs, it generally occurs together with a very small basal spine considered as homologous of the second seta (Antunes-Carvalho & Gnaspini 2015;Gnaspini et al 2017).…”