Exaesiopus torvus Reichardt, 1926

Lackner, Tomas, 2015, Revision of the genus Exaesiopus Reichardt, 1926 (Coleoptera, Histeridae, Saprininae), ZooKeys 479, pp. 65-108 : 81

Taxon classification Animalia Coleoptera Histeridae

Exaesiopus torvus Reichardt, 1926 Figs 55, 56-63, 64-72

Exaesiopus torvus Reichardt 1926: 17; Mazur (1984): 101; (1997): 264; (2004): 92; (2011): 210.

Type locality.

Yanidarya, Kyzyl-Ordinskij Rayon, Kazakhstan.

Type material examined.

Holotype, ♀ side-mounted on a triangular point, with female genitalia extracted and glued to the subsequent label with female sign, with following labels: “♀” (printed); followed by circular golden label; followed by: "Yany - Darya / perovsk u / Kyzyl-Kum / 24.iv.[1]911" (hand-written); followed by: "Type / Exaesiopus / torvus m. / A. Reichardt det." (written-printed label); followed by: “Holotypus” (red label, printed) (ZIN).

Additional material examined.

Kazakhstan: 1 ♀, left bank of the river Ural, Saraichikovsk, 8.vi.1932, Lukyanovich leg.; 1 ♀ + 2 specs., left bank of Ural river, opposite of Saraychik, 8.vi.1932, Lukyanovich leg.; 1 ♂, western bank of Aral Sea, Komsomolsk na Ustyurte, 31.v.1978, G. Medvedev; 1 spec., W Kazakhstan obl. [=reg.], Bilj-Agach, 4.vii.1952, L. Arnoldi (in leaf litter). (all exs. ZIN); 1 spec., 1933-102, left bank of the Ural River, Saraychik, 8.vi.[19]32, Lyukanovich (BMNH). Uzbekistan: 1 ♀, Karakum, Khiva, 3.v.1978, leg. Olexa; 1 ♂, ibid, but 1.-5.v.1979 (both exs. TLAN); RUSSIA: 1 spec., Astrakhan Region, Krasniy Yar district, near Dosang vill., 8.v.2009, A. Kovalyov leg. (CAS); 1 spec., ibid, but 14 km NE Dosang vill., barkhan [=sand dune] Tuvayak, 23-24.iv.2008, M. Smirnov leg. (CAS).

Diagnostic description.

Body length: PEL: 2.15-2.575 mm; APW: 0.575-0.875 mm; PPW: 1.625-1.925 mm; EW: 1.75-2.125; EL: 1.375-1.625 mm. Body (Fig. 55) strongly convex, cuticle as in Exaesiopus grossipes , but without metallic tinge; legs, mouthparts and antennae dark yellow to light brown. Antennae as in Exaesiopus grossipes ; sensory structures of the antennal club not examined. Mouthparts: labrum obscurely variolate, shallowly depressed medially; mentum as in Exaesiopus henoni ; rest of the mouthparts similar to those of Exaesiopus grossipes ; terminal labial and maxillary palpomeres truncate. Clypeus (Fig. 56) as in Exaesiopus grossipes , but rugulose-lacunose; frontal, supraorbital and postorbital striae (Fig. 57) as in Exaesiopus grossipes ; frons rugose, with several irregularly shaped carinate transverse rugae or chevrons intermingled with sparse microscopic punctures. Pronotum: pronotal disc, except for irregularly-shaped impunctate (or weakly punctate) median part entirely covered with round dense punctation, forming transverse rugae and confluent laterally, punctation reaches lateral margins; rest of pronotum as in Exaesiopus grossipes .

Elytral humeri not particularly enlarged; inner subhumeral stria present only as a row of several punctures; elytral punctation variable, in most specimens reaching elytral base along fourth elytral interval, punctures often present in all elytral intervals, elytral flanks impunctate; punctures regular and deep, separated by about half to several times their own diameter. Propygidium (Fig. 58) and pygidium as in Exaesiopus grossipes , but covered with denser punctation. Prosternum: prosternal foveae (Fig. 59) weakly impressed; prosternal process otherwise similar to that of Exaesiopus grossipes . Disc of mesoventrite (Fig. 60) with scattered shallow punctures; intercoxal disc of metaventrite, lateral disc of metaventrite and metepisternum generally similar to those of Exaesiopus henoni . Intercoxal disc of first abdominal sternite as in Exaesiopus grossipes . Protibia (Fig. 61) more dilated than that of Exaesiopus grossipes ; on outer margin with two widely-spaced low teeth, topped by large triangular denticle followed by two low rounded denticles imbedded in outer protibial margin; protibial spur inconspicuous (absent?) protibia otherwise similar to that of Exaesiopus grossipes . Mesotibia (Fig. 62) generally similar to that of Exaesiopus grossipes . Metatibia (Fig. 63) perhaps most triangularly dilated and thickened of all congeners; outer margin with approximately three widely-spaced tiny denticles; inner margin with a dense row of minuscule rounded denticles; no rows of denticles present between the two rows, surface rugulose-lacunose.

Male genitalia. Eighth (Figs 64-65) sternite apically asetose, with tiny vela; eighth tergite apically faintly inwardly arcuate medially; eighth sternite and tergite fused laterally (Fig. 66). Ninth tergite (Figs 67-68) apically almost straight; tenth tergite apically outwardly arcuate, basally only faintly inwardly arcuate. Spiculum gastrale (Figs 69-70) generally similar to that of Exaesiopus grossipes . Aedeagus (Figs 71-72) almost parallel-sided, apex with pseudopores, parameres fused along their apical half (approximately); aedeagus slightly curved ventrad from the lateral view (Fig. 72).

Differential diagnosis.

Generally the most punctate species of Exaesiopus , which can be confused only with densely punctate specimens of Exaesiopus grossipes from N Africa. It clearly differs from them by the punctation of pronotum as well as male genitalia (see also Key to species for details).

Biology.

Similar to that of other congeners - beetles are found in sand.

Distribution.

Kazakhstan; new to Uzbekistan and Russia.