Liparocephalini Fenyes, 1918, 1894

Tasaku, Yuto, Ono, Hiroki & Maruyama, Munetoshi, 2023, Review of the intertidal rove beetle tribe Liparocephalini Fenyes (Coleoptera, Staphylinidae, Aleocharinae) from Japan, Zootaxa 5383 (3), pp. 251-296 : 252

Tribe Liparocephalini Fenyes, 1918

Remarks. Ahn (2004) and Ahn et al. (2010) defined the monophyletic lineage of Liparocephalini , characterized by shared character states, including the absence of seta v on the mentum, the presence of a single medial seta on the prementum, contiguous mesocoxal cavities, and the galea bearing several setae on the mesal surface and apex. Here we validate these proposed characteristics.

Firstly, with regard to the absence of “seta v” on the mentum, it is essential to note that seta v represents one of three setae situated on the anterior margin of the mentum. Originally identified by Sawada (1970), it has proven valuable for taxonomy of the tribe Athetini . However, in Liparocephalini , the morphological variability of the mentum, when contrasted with Athetini , raises significant challenges in reliably identifying seta v ( Figs. 7B , 8D , 10D , 22B ). Consequently, its utility as a defining character state for asserting the tribe’s monophyly remains open to question.

Secondly, the presence of “a single medial seta on the prementum” is not consistently observed in all Liparocephalini species. For instance, Diaulota and Rotundicephala gen. n. lack a medial seta ( Figs. 7C , 8C , 10C , 12C , 16C ), while Halorhadinus exhibits two medial setae ( Fig. 20D ), and Liparocephalus and Paramblopusa display variable numbers (0–2).

Finally, the character states “contiguous mesocoxal cavities” and “galea with several setae exclusively on the mesal surface and apex with setae” have been refuted by Maruyama & Hayashi (2009).As a result, the morphological characteristics of Liparocephalini remain inconclusive. For further insights, refer to the discussion section.

Figures

FIGURE 7 Mouthparts of Diaulota aokii. A, labrum, right side, dorsal view; left side, ventral view (epipharynx); B, mentum; C, labium; D, maxilla; E, right mandible. Scale bars: 0.1 mm.

FIGURE 8 Diaulota uenoi. A, habitus, male; B, ditto, female; C, labium; D, mentum; E, median lode of aedeagus, lateral view; F, internal structure of median lobe, dorsal view; G, ditto, ventral view; H, spermatheca. Scale bars: 1.0 mm for A, B; 0.1 mm for C–H. Abbreviation: as, apical sclerite; su, suspensonia.

FIGURE 10 Habitus and mouthparts of Diaulota submarina. A, habitus, male; B, ditto, female; C, labium, D, mentum. Scale bars: 1.0 mm for A & B; 0.1 mm for C & D.

FIGURE 12 Diaulota orientalis sp. n. A, habitus, male (holotype); B, ditto, female (paratype); C, labium; D, mentum; E, median lode of aedeagus, lateral view; F, internal structure of median lobe, ventral view; G, spermatheca. Scale bars: 1.0 mm for A & B; 0.1 mm for C–G.

FIGURE 16 Mouth parts of Rotundicephala koheii sp. n.A, labrum (right side, dorsal view; left side, ventral view (epipharynx)); B, mentum; C, labium; D, maxilla; E, right mandible. Scale bar: 0.1 mm.

FIGURE 20 Halorhadinus aequalis. A, Habitus; B, labrum (right side, dorsal view; left side, ventral view (epipharynx)); C, mentum; D, labium; E, maxilla; F, right mandible; G, apical lobe of paramere. Scale bars: 1.0 mm for A; 0.1 mm for B–G.

FIGURE 22 Mouth parts of Paramblopusa borealis. A, labrum (right side, dorsal view; left side, ventral view (epipharynx)); B, mentum; C, labium; D, maxilla; E, right mandible. Scale bar: 0.1 mm.