Exaesiopus Reichardt, 1926

Lackner, Tomas, 2015, Revision of the genus Exaesiopus Reichardt, 1926 (Coleoptera, Histeridae, Saprininae), ZooKeys 479, pp. 65-108 : 67-68

Taxon classification Animalia Coleoptera Histeridae

Exaesiopus Reichardt, 1926

Exaesiopus Reichardt 1926: 14. Type species Saprinus grossipes Marseul, 1855, original designation.

Exaesiopus : Reichardt (1941): 156, 329; Peyerimhoff (1936): 226; Kryzhanovskij and Reichardt (1976): 112, 232; Mazur and Kaszab (1980): 7, 61; Vienna (1980): 117, 195; Mazur (1984): 101; Mazur (1997): 263; Yélamos (2002): 245, 338; Mazur (2004): 92; Lackner (2010): 63, 111; Mazur (2011): 210.

Diagnosis.

Although the genus has been recently diagnosed ( Lackner 2010: 111), it requires modification to accommodate the newly examined species Exaesiopus laevis , the newly included Exaesiopus glaucus (Bickhardt), and the newly described Exaesiopus therondi . Body in most species strongly convex, especially dorsally; cuticle light to dark brown to almost black, in several species with (feeble) green lustre. Clypeus anteriorly elevated (Fig. 4); frontal stria carinate (Fig. 2); frons with several chevrons, occasionally surrounded by numerous tiny rugae (Fig. 2); pronotal hypomeron setose (Fig. 55). Elytra in most species with punctation; in all species striate; pleura and sterna furnished with short setae (Fig. 41). Prosternum with both sets of striae complete, and occasionally with weakly impressed prosternal foveae (Fig. 6). Protibia with 2-3 (large) teeth topped by triangular denticle; protibial spur in most species inconspicuous (apparently absent); metafemora thickened; metatibiae triangularly dilated and thickened (except for Exaesiopus glaucus ).

Differential diagnosis.

Members of Exaesiopus are generally morphologically most similar to the Old World species of the genus Hypocaccus , differing from them chiefly by the setose pronotal hypomeron, strongly convex body, thickened metafemora and triangularly dilated and thickened metatibiae. In North America, however, there are at least two species of Hypocaccus ( Hypocaccus propensus (Casey, 1893) and Hypocaccus servilis Casey, 1893) that are characterized by the presence of hypomeral setae.

Biology.

Exaesiopus species are almost exclusively found in sandy soils, beach dunes, river sands, and are also found in sandy areas further inland (e.g. Sahara desert). Morphologically they are well adapted to their fossorial habits. Species are often collected on rotting biological matter, e.g. under faeces, dead fish etc., and are occasionally found under coastal wrack or by shore washing. The middle Asian Exaesiopus atrovirens and Exaesiopus torvus are sometimes found burrowing under Tamarix . The biology of Exaesiopus laevis and Exaesiopus therondi is unknown, the latter has been found inside the stomach of Kentish plover ( Charadrius alexandrinus L. ( Aves)).

Distribution.

Genus Exaesiopus has a generally circum-Mediterranean-Caspian-Turanian distribution, most westerly occurring on the Canary Islands, reaching Afghanistan in the east. Its members have also been collected in the Sahara desert (Laghouat, Algeria), reaching as far east as northern Somalia ( Exaesiopus laevis ) or Djibouti ( Exaesiopus henoni ). Exaesiopus glaucus is known only from the Republic of South Africa and Namibia.