Platymetopus Dejean, 1829

Kataev, Boris M., 2023, A review of Asian species of the genus Platymetopus (Coleoptera: Carabidae: Harpalini), Zootaxa 5306 (5), pp. 501-536 : 503

Genus Platymetopus Dejean, 1829

Platymetopus Dejean, 1829: 4 , 68 (as genus). Type species: Platymetopus vestitus Dejean, 1929 , designated by Hope (1838: 88).

Diagnosis. The members of this genus are readily recognizable by short mandibles, almost not bent apically (except for P. figuratus pictus ), setaceous paraglossae, and densely punctate and pubescent body almost throughout, including scrobe of mandibles and labrum.

Description. Body medium sized, rather densely punctate and pubescent almost throughout, including scrobe of mandibles and labrum. Head relatively large, without clypeo-ocular furrows; frontal foveae indistinct. Clypeal apex in many species more or less markedly emarginate and labral base often exposed dorsally. Mentum separated from submentum by complete transverse suture, without a median tooth (in some species apical margin slightly convex medially). Epilobes widened apically. Ligular sclerite narrow, with two ventroapical setae. Paraglossae very wide, rounded apically, setaceous at margins and on dorsal side laterally. Mandibles in most species modified: very short, not or only slightly bent apically, with almost straight mesal margin; left and right mandibles in repose almost not intersecting (in P. figuratus pictus more elongate and curved apically); dorsal surface with longitudinal wrinkles. Elytra with a parascutellar pore and a long parascutellar (abbreviated) striole. Elytra without dorsal setigerous pores on intervals 3, 5 and 7 or with such pores (e.g., in the Afrotropical P. interpunctatus Chaudoir, 1878 and P. seriatus Dejean, 1829 ). Protibia with one to three preapical spines on outer margin. Metacoxa without a posteromedial pore. Metafemur with two setigerous pores along posterior margin. Metatarsomere 1 elongate, approximately as long or slightly shorter than metatarsomeres 2 and 3 combined. Male pro- and mesotarsi widened and with biseriate adhesive vestiture ventrally. Laterotergite with one or several setae apically; gonosubcoxite with one setae apically; gonocoxite with one or two thin setae on dorsal ridge of outer side near base. Median lobe with apical orifice in dorsal position.

Larva is described for P. flavilabris ( Fabricius, 1798) ( Habu & Sadanaga 1965, Habu 1973).

Karyotype 2 n = 40 ( Yadav et al. 1985, Serrano et al. 1994).

Composition and distribution. The genus comprises 33 species, 28 of which are known from Afrotropical Africa and Madagascar, four species from South and South East Asia, and one species is distributed both in Afrotropical Africa and in South Asia.

Remarks. Modified, very short mandibles, not bent apically in most species of Platymetopus are a unique feature among Harpalini , apparently associated with a specific type of food. Unfortunately, there is no information about the nutrition of species in nature. In the laboratory, adults and larvae of P. flavilabris were reared with lepidopterous pupae and larvae ( Habu 1973).

The taxonomic position of the genus is still unclear. Most of the old authors considered this taxon to be a congeneric or close to the genus Dioryche MacLeay, 1825 , and Basilewsky (1950) and Noonan (1976) included it in the Selenophori genus group, but more recently Noonan (1985) treated Platymetopus as a member of Harpali genus group due to its setaceous paraglossae. However, the relationship of this genus to Harpali seems highly questionable based on this feature alone. In the combination of other characters (general habitus, elytral intervals of some species with rows of setigerous pores on intervals 3, 5 and 7, metafemur with two setigerous pores along posterior margin, metatarsomere 1 elongate, median lobe with apical orifice in dorsal position), Platymetopus is rather similar to other selenophorines and probably represents a lateral branch descending from Selenophori-like ancestor. The setaceous paraglossae, the only feature that distinguishes Platymetopus from Selenophori, appears to have arisen in this genus independently of Harpali as well as in some representatives of Anisodactylina (e.g., Crasodactylus Guérin-Méneville 1847 and Progonochaetus Müller, 1938 ) and Ditomina (e.g., Chilotomus Chaudoir, 1842 , Pachycarus Solier, 1834 , Tschitscherinellus Csiki, 1906 and Machozetus Chaudoir, 1850 ) most members of which have glabrous paraglossae. Molecular data does not support a close relationship of Platymetopus to Harpali ( Martinez-Navarro et al. 2005). The closer relationship of the genus to Selenophori is also indirectly confirmed by its geographical distribution in the Afrotropical and Oriental regions. According to my data ( Kataev 2009), Harpali genus group apparently originated in the Holarctic, where they are predominantly distributed now, and whence they came to Africa, where their modern distribution is limited to the eastern and southern regions. There are no recent genera of Harpali widely distributed in the Afrotropical and Oriental regions.