Megalinus Mulsant & Rey 1877
Creators: name: Assing, Volker
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Megalinus

description: The genus Megalinus Mulsant & Rey, 1877
Xantholinus (Megalinus) Mulsant & Rey, 1877: 261.
Leptophallus Coiffait, 1956a: 59 [preocc.]; syn. n.
Leptophius Coiffait, 1983: 345 [replacement name for Leptophallus Coiffait, 1956]; syn. n.
Comment. Leptophallus was originally described as a subgenus of Xantholinus to include Xantholinus relucens sensu Kraatz (1857) (type species by original designation and later to be identified as X. flavocinctus Hochhuth, 1849) and X. elianae Jarrige, 1941, and distinguished from other subgenera by the small and slen- der aedeagus without distinct spines (Coiffait 1956a). Subsequently, two additional species were attributed to the subgenus, X. anatolicus Coiffait, 1965 from Turkey and X. minutus Coiffait, 1962 from Algeria (Coiffait 1972). The preoccupied name Leptophallus was replaced with Leptophiu s by Coiffait (1983).
Megalinus, too, was originally described as a subgenus of Xantholinus to include the type species (by monotypy) Xantholinus glabratus (Gravenhorst, 1802) and separated from other subgenera by the shape of the mesosternal process (Mulsant & Rey 1877). Nearly a century later, Coiffait (1972) elevated Megalinus to the rank of genus—at that time including three species, M. glabratus, M. oasis (Steel, 1948), and M. scutellaris (Fauvel, 1900) —stating that it was distinguished from Xantholinus by the modified genital segments (lateral tergal sclerites IX extending clearly beyond posterior margin of the short and weakly sclerotised tergite X).
Emphasising the evident modifications of the genital segment and the particular morphology of the aedeagus of Xantholinus flavocinctus, Bordoni (1985) recognised Leptophius as a distinct genus. Arguing that in X. minutus and X. anatolicus the genital segments were of the typical Xantholinus condition, he attributed these two species to the new subgenus Neoleptophallus. In addition, he described the genus Lemiganus to include the fourth species previously in Leptophius, X. elianae, stating that, despite obvious similarities, it was not possible to attribute it to Megalinus owing to the less deep median incision of the labrum, the different morphology of the aedeagus (small and slender, distally with long "lobi laterali", sclerotised internal structures absent), and the somewhat different shape and chaetotaxy of the sclerites of the genital segments (tergites IX and X, sternite IX).
A comparison of Leptophius flavocinctus, Megalinus glabratus, and Megalinus scutellaris revealed, however, that they are doubtlessly congeneric. True, there are differences in the morphology of the genital sements—the lateral tergal sclerites IX are somewhat shorter and slightly differently shaped in L. flavocinctus than in M. glabratus and M. scutellaris—, but they are clearly autapomorphic and the principle morphology is highly similar. Also, what Bordoni (1985) refers to as "lobi laterali" in Leptophius (and Lemiganus) is clearly not homologous to the "lobi laterali" in Xantholinus. The conspicuous distal sclerotised structure of the aedeagus in Megalinus, Leptophius, and Lemiganus represents an evident synapomorphy; for comparison see figure 5 (aedeagus of Lepidophallus denticulatus, now a synonym of Megalinus scutellaris) in Bordoni (2004), figure 10 (Leptophius flavocinctus) in Bordoni (1985), and figure 16 (Lemiganus elianae) in Bordoni (1985). The reduced size and internal structures of the aedeagus of L. flavocinctus must be regarded as an autapomorphy (known also from other genera of Xantholinini) and is no convincing argument to consider Leptophius a distinct genus. In consequence, Leptophius is here placed in the synonymy of the senior name Megalinus. It seems most likely that Lemiganus, too, will eventually have to be synonymised with Megalinus, but so far I have not been able to examine a male of L. elianae.
description: Published as part of Assing, Volker, 2007, On the Xantholinini of Turkey and adjacent regions (Coleoptera: Staphylinidae: Staphylininae), pp. 1-54 in Zootaxa 1474 on pages 43-44, DOI: 10.5281/zenodo.176738