Osoriellus mexicanus ( BERNHAUER, 1910 ) Irmler, 2014

Irmler, Ulrich, 2014, The Neotropical species of the genus Osoriellus FAGEL, 1959 (Coleoptera: Staphylinidae: Osoriinae), Beiträge Zur Entomologie = Contributions to Entomology 64 (2), pp. 231-354 : 277-278

Osoriellus mexicanus ( BERNHAUER, 1910) new combination

( Figs 75 A-B, 99B)

Osorius mexicanus BERNHAUER, 1910: 371

Type material examined: Mexico: Oaxaca, Mitla , 96°17'E, 16°54'N, female (holotype in FMNH) .

Further material examined: Mexico: Tepic , Nayarit, female, 2.- 7.8.1947, leg. B. Malikin ( AMNH) ; Real de Arriba (93°52'W, 16°13'N), 3 females, 1.7.1932, leg. H.E. Hinton ( AMNH) ; San Luis Potosi, Xilitla , 23.7.1954, leg. Univ. Kansas Mex. Expedition ( KNHM) ; Guatemala: Baja Verapaz, 4 km SW Purulha, 1700 – 1800 m elevation, biotope del Quetzal , under stones and pieces of wood, cloud forest, female, 27.11.1991, leg. R. Baranowski ( SMNH) ; Antigua, 5 km E, 1780 m elevation sifting litter, tropical montane forest, female, 7.11.1991, leg. R. Baranowski ( UIC) .

Diagnosis: The species is very similar to O. cordovensis in the size, the shape of the pronotum and the absence of microsculpture on head and pronotum. It can be differentiated from O. cordovensis by the sparser, but larger punctures of the pronotum and the absence of digits on the outer edge of the protibia. It differs from O. brevipennis by the less triangular shape of the pronotum. It highly coincides with O. argentinus . But O. argentinus has at least remains of microsculpture on the head, whereas the head of O. mexicanus is without microsculpture and polished.

Description: Length: 5.1 mm; Colouration: Dark red; elytra lighter red than head and pronotum; abdomen distinctly darker; front legs red; middle and hind legs as well as antennae yellow.

Head: 0.60 mm long, 1.00 mm wide; eyes as long as temples; front edge of clypeus even with short acute granules at angles; with deep and large setiferous punctures; interstices between punctures much shorter than diameter of punctures; punctation on clypeus less dense than on vertex; moderately wide midline impunctate; between coarse punctures with sparse micro-punctation; on supraocular area with partly coriaceous punctation; on vertex without microsculpture; surface polished; on supraocular and postocular area with dense longitudinally reticulate microsculpture; surface matt.

Antennae with second and third antennomeres equally long; fourth to sixth antennomeres quadrate; following antennomeres much thicker than preceding antennomeres and wider than long.

Pronotum: 1.00 m long, 1.10 mm wide; widest at anterior edge; distinctly and evenly convergent to posterior angles; posterior edge nearly half as wide as anterior edge; setiferous punctation deep, but distinctly sparser than on head; interstices between punctures as wide as or slightly wider than diameter of punctures; on each side of impunctate midline with row of 6 punctures; between coarse punctures with sparse micro-punctation; surface without microsculpture, polished.

Elytra: 1.05 mm long, 1.05 mm wide; with coriaceous ground-sculpture and weak and sparse setiferous punctation; punctures nearly invisible in deep ground-sculpture; surface shiny.

Abdomen deeply and densely punctate; on average, interstices between punctures shorter than diameter of punctures except on relatively small impunctate midline; surface without microsculpture, shiny.

Protibia: 0.73 mm long, 0.23 mm wide; 10 spines at outer edge; spines not inserted on digits; WLR: 6,0; in posterior aspect, comb at inner emargination visible throughout its total length; posterior face densely covered by long setae.

Aedeagus unknown.

Figures

Fig. 73-78: Osoriellus-s. str.-group: Osoriellus frater (73), O. latipes (74); O. mexicanus (75), O. brevipennis (76), O. argentinus (77), O. crassus (78); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.