Eremosaprinus Ross, 1939

Lackner, Tomáš, 2010, Review of the Palaearctic genera of Saprininae (Coleoptera: Histeridae), Acta Entomologica Musei Nationalis Pragae (suppl.) 50, pp. 1-254 : 100

Eremosaprinus Ross, 1939

Eremosaprinus Ross, 1939: 39 (as a subgenus of Saprinus ). Eremosaprinus: ROSS (1940) :1; BLACKWELDER & BLACKWELDER (1948):11; WENZEL (1962):374,380; KRYZHANOVSKIJ & REICHARDT (1976): 111, 122; MAZUR (1984): 106; MAZUR (1997): 216; MAZUR (2001): 19; MAZUR (2004): 91.

Erebidus Reichardt, 1941: 161 , 170 (as a subgenus of Gnathoncus ). Type species: Gnathoncus vlasovi Reichardt, 1941, by monotypy. Synonymized by KRYZHANOVSKIJ & REICHARDT (1976): 122.

Type species: Saprinus unguiculatus Ross, 1939 , original designation.

Diagnosis. Body flattened from above; cuticle never metallic; frontal, supraorbital striae absent; antennal scape and pedicel slender, elongated; antennal club elongated; lacinial hook present. Pronotal foveae, pre-apical foveae and lateral prosternal striae absent, carinal prosternal striae present; prosternal process flat and broad; outerlateral costa reaches prosternal process, basal margin distinctly elevated; meso-metaventral sutural stria sinuate, distanced from meso-metaventral suture. Venter of body asetose. Protibia on explanate posterior surface with row of about 15 denticles; meso- and metatibiae long, slender; ninth tergite divided longitudinally.

The diagnosis of the genus Eremosaprinus is here based not on the genus’ type species, but on its single Palaearctic representative instead. This is mainly due to the fact that this work deals primarily with the Saprinine of the Palaearctic region.

Differential diagnosis. This taxon is most similar to the species of the genus Gnathoncus differing from it by absent lateral prosternal striae and shape of protibia. From the species of the genus Saprinus it differs likewise by the absent lateral prosternal striae, shape of the protibia as well as by the absence of supraorbital stria (present in Saprinus ).

Biology. Eremosaprinus is an inquilinous genus, collected in sandy regions as well as on the clay soils. Beetles are found exclusively in rodent nests, found in the burrows of Spermophilopsis leptodactylus (Lichtenstein, 1823) , Meriones erythrourus (Gray, 1842) and Rhombomys opimus (Lichtenstein, 1823) in Central Asia and kangaroo rats ( Dipodomys sp.) for the North American species, and are morphologically well adapted to the inquilinous way of life ( REICHARDT 1941, KRYZHANOVSKIJ & REICHARDT 1976).

Distribution. This genus contains four North American and one Palaearctic species. Palaearctic species Eremosaprinus vlasovi occurs in the Central Asian province of Turan (recorded from Turkmenistan, Kazakhstan and Uzbekistan).

Species examined. Eremosaprinus vlasovi ( Reichardt, 1941) .

Notes on taxonomic status. The genus Eremosaprinus was originally described as a subgenus of the genus Saprinus , but later the same author used it in full generic status without any explanation or listing any of its species ( ROSS 1940). BLACKWELDER & BLACKWELDER (1948) listed it as a valid genus with all its species referring to ROSS (1940) in a footnote ‘Considered a distinct genus’. MAZUR (1997) overlooked the Catalogue of BLACKWELDER & BLACKWELDER (1948) and proposed a new combination for all species of Eremosaprinus .

Discussion. The preliminary phylogenetic analysis of the genera of the Palaearctic Saprininae (LACKNER, in prep.) suggests that taxa Eremosaprinus and Gnathoncus together with Myrmetes compose the most basal clade of the Palaearctic Saprininae , supported by several putative synapomorphies among which are the completely absent frontal and supraorbital striae and ninth tergite of the male genitalia divided into two parts. Eremosaprinus shares similar sensory structures of antennal club with Gnathoncus , but is devoid of lateral prosternal striae, which is probably an apomorphic character. Presence of lacinial hook is another ‘strong’ character supporting its relationship with Gnathoncus . Eremosaprinus vlasovi was originally described in a newly created subgenus Erebidus of the genus Gnathoncus and only later (Kryzhanovskij in KRYZHANOVSKIJ & REICHARDT 1976: 122) transferred it into hitherto North American genus Eremosaprinus . It is believed (Tishechkin, pers. comm. 2009) that the North American representatives of this genus are quite different from their Central Asian congener and perhaps they constitute two different genera. It is hoped here that further study of this genus will clarify their exact taxonomic position.