Xenocerogria Merkl, 2007

Zhou, Yong, Merkl, Otto & Chen, Bin, 2014, Notes on the genus Xenocerogria (Coleoptera, Tenebrionidae, Lagriini) from China, ZooKeys 451, pp. 93-108 : 95-96

Taxon classification Animalia Coleoptera Tenebrionidae

Xenocerogria Merkl, 2007

Xenocera Borchmann, 1936: 116 (not Broun, 1881: 668). Type species: Lagriocera feai Borchmann, 1911, by original designation.

Xenocerogria Merkl, 2007: 269 (replacement name); Merkl 2008: 116.

Diagnosis.

The genus was thoroughly described by Borchmann (1936), so only the most important characteristics are mentioned here. Male: Body small, body length 5-10 mm. Head slightly rounded. Apical maxillary palpomere securiform and thick. Labrum with anterior margin more or less emarginate. Clypeus with anterior margin emarginate, exposing labroclypeal membrane. Frontoclypeal suture deep and arcuate. Antennae strong, antennomeres 9 and 10 strongly transverse, with produced anterolateral corner, antennomere 11 strongly elongate, as long as combined length of at least 4 preceding antennomeres, concave ventrally. Pronotum slightly convex, slightly narrower than head. Elytra about 2 × as wide as pronotum, slightly broadened toward apex, without striae, with irregular, but evenly scattered punctation. Legs simple, moderately robust; femur not clavate, tibia nearly straight, without modifications. Female: Similar to male but larger and broader. Antennomere 11 shorter than combined length of 3 preceding antennomeres. Pronotum slightly wider than head. Elytra more broadened toward apex.

Distribution.

China, India, Burma, Java, Sumatra.

Remarks.

This genus is distinguished from other lagriine genera on the basis of the male antenna: antennomeres 9 and 10 are strongly transverse; the terminal antennomere is concave in ventral surface, with length equal to at least combined length of 4 preceding antennomeres (female with shorter terminal antennomere). This antennal structure is combined with unmodified male tibiae. These characteristics make this genus vaguely defined, and it is possibly an artificial assemblage of species not closely related to each other. Even Borchmann (1936) himself emphasized that one of the species, Xenocerogria andrewesi (Borchmann, 1925) is somewhat different from other species: antennae are more slender, only antennomere 10 is transverse, and pronotum of female with a wide longitudinal impression.

The situation is similar in most genera of the tribe Lagriini . Most of the species of the subtribe Lagriina were originally described as members of the genus Lagria Fabricius, 1775. Later, species with unusual (apomorphic) characters were transferred from Lagria to separate genera established mainly by Borchmann, for instance Aulonogria Borchmann, 1929, Cerogria Borchmann, 1909, Neogria Borchmann, 1911 and Schevodera Borchmann, 1936, just to mention a few from East and Southeast Asia. However, these genera are defined mostly by modifications of male antennomeres and tibiae. Females not associated with males are difficult or virtually impossible to separate at generic level. The remaining species were retained in the genus Lagria . In fact, modifications can frequently be observed on the male antennae and legs of species of Lagria , although these are not as prominent as in Cerogria , for instance. The genus Lagria itself, used as a dumping ground for more “simple” species is therefore still quite diverse, and most of the Oriental species are rather different from the type species, the western Palaearctic Lagria hirta (Linnaeus, 1758).

Removal of species with unique characters, creating a hardly treatable mass of less distinctive species in a large genus is common throughout the Coleoptera , including the family Tenebrionidae (see comments by Campbell 2014 and Schawaller 2014). A natural classification of the subtribe Lagriina would be achieved by study of (often unavailable) types of all described species supported by extensive molecular studies, but this must be an enormous undertaking.

Key to Chinese species presently and formerly assigned to Xenocerogria