Liparocephalini Casey 1894
Creators: name: Tasaku, Yuto
name: Ono, Hiroki
name: Maruyama, Munetoshi
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae

description: Systematics of Liparocephalini
In this study, we recognize six genera of Liparocephalini from Japan and found that they can be classified into three genus-groups: the Liparocephalus genus-group comprises Liparocephalus, Diaulota, and the newly described Rotundicephala gen. n.; the Amblopusa genus-group consists of Amblopusa and Halorhadinus. Lastly, we have the Paramblopusa genus-group including only Paramblopusa. Within these delineated groups, the Liparocephalus and Amblopusa groups share notable similarities in the structure of the labial palpus: typically comprising two palpomeres, occasionally three, with palpomere II generally commensurate in width to palpomere I. The palpomere I is conspicuously longer than II, as visually depicted in Figures 4C, 7D, 8C, 10C, 12C, 16C, 19C, and 20D. It is highly plausible that these two genus groups, inclusive of the type genus of the tribe, represent monophyletic assemblages, collectively constituting the core Liparocephalini. Conversely, the Paramblopusa group is distinguished from these core Liparocephalini through the 3-palpomere labial palpus, with palpomere II being more slender than I, as in Figure 22C. These distinctive characteristics render its inclusion within the Liparocephalini taxon less tenable. A comprehensive inquiry is requisite to ascertain the precise taxonomic placement of Paramblopusa.
Other genera within Liparocephalini, namely Ianmoorea Ahn, 2006, distributed in New Zealand, and Ashella Klimaszewski, 2020, known from the US, exhibit a stronger affinity with the Salinamexus Moore & Legner, 1977, which currently holds an uncertain tribal classification (Maruyama, 2011; Newton, 2022), than the core Liparocephalini. Notably, Ianmoorea and Salinamexus share the following characteristics: a diamond-shaped apical lobe of the paramere (Fig. 14 in Ahn, 2004; Figs. 12, 21, 31 in Maruyama, 2011); a depressed apical margin of male tergite VIII (Fig. 11 in Ahn, 2004), and a trapezoidal mentum with a truncate anterior margin (Fig. 9 in Ahn, 2004; Fig. 6 in Jeon & Ahn, 2007). While Ashella has not yet illustrated its mouthparts, the body shape (Fig. 21. 259a in Klimaszewski, 2020) and the shape of the male tergite VIII (Fig. 21. 259d in Klimaszewski, 2020) bear resemblance to those of Salinamexus (Figs. 1–3, 9, 18 & 27 in Maruyama, 2011). Furthermore, the characteristics of the mentum and male tergite VIII, though they exhibit homoplasy, are also shared with Actocharis Sharp, 1870, the sole genus of the tribe Actocharini Bernhauer & Schubert, 1911 known from the western Palearctic coastal region (Figs. 2, 3b & 4b in Assing, 1992). We hypothesize that these four genera are likely closely related, and Ianmoorea and Ashella are provisionally excluded from Liparocephalini. In Orlov et al. (2021), Actocharis (Actocharini) is postulated as a sister group or ingroup of Liparocephalini. However, their analysis did not encompass the Amblopusa group of Liparocephalini, and the accurate systematic position of Actocharini and monophyly of the aforementioned four genera still necessitate further discussion.
Baeostethus Broun, 1909 cannot be thoroughly discussed as important characteristics are not described in Pace (1989) and Leschen et al. (2002), but the dorsal habitus (Fig. 1I in Orlov et al., 2020) shows striking similarities to the Liparocephalus group. Here we regard it as incertae sedis within Liparocephalini.
Hence, we consider the core Liparocephalini with five genera: Liparocephalus, Diaulota, Rotundicephala gen. n., Amplopusa, and Halorhadinus. The affiliation of other genera will need to be addressed in future studies.
The coastal Aleocharinae are taxonomically not well understood due to their similar morphological specialization resulting from coastal adaptation. Moreover, the misidentification highlighted in this study has further contributed to the confusion. Although most of these issues have been resolved in our study, future phylogenetic analyses of the entire subfamily Aleocharinae will be necessary to elucidate their relationships with other tribes.
description: Published as part of Tasaku, Yuto, Ono, Hiroki & Maruyama, Munetoshi, 2023, Review of the intertidal rove beetle tribe Liparocephalini Fenyes (Coleoptera, Staphylinidae, Aleocharinae) from Japan, pp. 251-296 in Zootaxa 5383 (3) on page 290, DOI: 10.11646/zootaxa.5383.3.1, http://zenodo.org/record/10361564