Espeson mexicanus FAUVEL , 1902:37

Irmler, U., 2012, The Neotropical species of the genera Pseudespeson L, 1994 and Espeson S, 1882 (Coleoptera: Staphylinidae: Osoriinae), Beiträge Zur Entomologie = Contributions to Entomology 62 (2), pp. 331-360 : 341-342

Espeson mexicanus FAUVEL, 1902:37 ( Figs 4 a-e, 17C)

Type material examined:

Mexico: 1 female, without further data (holotype, IRSNB)

Additional material examined:

Mexico: Prov. Veracruz, 1 mi. S Huatusco (96°57'W, 19°8'N), Berlese extraction, 1344 m elevation, 45 specimens, 2.8.1969, leg. S. & J. Peck ( AMNH, UIC) .

Diagnosis:

The species resembles E. simplex , E. franiae , E. dybasi , and E. hermani in the darker reddish colouration and it size of at least 2.0 mm. It can be differentiated from the similarly large E. hermani by the position of the pronotal impression. In E. mexicanus the longitudinal impression is placed in the posterior half and drop-shaped, whereas in E. hermani the longitudinal impression is placed in the anterior half. Moreover, the elytra in E. hermani are lighter red than head and pronotum, whereas no different colouration between head, pronotum, and elytra is found in E. mexicanus . In males, tergite VIII and aedeagus distinctly differ between the two species. E. simplex , E. dybasi , and, in particular, E. franiae are larger with at least 2.3 mm length. In E. simplex a pronotal impression is absent, in E. dybasi and E. franiae the pronotal impression is placed also in the posterior half, but with a circular shape.

Description:

Length: 2.0 mm. Colour: dark reddish, elytra dark yellow, antennae and legs yellow. Head: 0.28 mm long, 0.36 mm wide; eyes 0.3 times longer than temples; temples smoothly rounded; punctation dense and deep; distance between punctures half as wide as diameter of punctures; a space in the middle of disc without punctures; without microsculpture; surface polished.

Antennae as long as head and pronotum combined; 2 nd and 3 rd antennomeres equal in length; following antennomeres quadrate and slightly increasing in width; 8 th antennomere slightly smaller than preceding and following antennomeres.

Pronotum: 0.30 mm long, 0.38 mm wide; distinctly emarginate in front of posterior edge; sides in front of emargination smoothly rounded; widest in anterior third; 0.3 times wider than at posterior angles; punctation deep and dense; on average distance between punctures half as wide as diameter of punctures; at posterior edge with coriaceous punctation; a longitudinal impression in the anterior half; with sparse and weak microsculpture; surface shiny.

Elytra: 0.48 mm long, 0.53 mm wide; punctation similar as on pronotum; without microsculpture; surface polished.

Abdomen with sparser and finer punctation as on elytra, but microsculpture more distinct; surface less shiny than on elytra; abdominal tergite VIII slightly narrowed posteriad and with undulate straight edge; with few longer setae among sparse pubescence.

Aedeagus with slender, more or less straight apical part placed in obtuse angle to basal part of central lobe; paramera thick and long with large apical transparent plate; diameter of apical plate nearly as long as length of apical segment of paramera.

Figures

Figs 3-5: Espeson euplectoides (3), E. mexicanus (4), E. microphthalmus (5); a: fore body, b: antenna, c: aedeagus, e: abdominal tergite VIII of male (scale bar: a, b: 0.5 mm, c, e: 0.1 mm).