Somoleptus curtioculatus, Irmler, 2024

Irmler, Ulrich, 2024, Additions to Neotropical species of the genera Lithocharodes Sharp, 1881 and Somoleptus Sharp, 1881 (Coleoptera, Staphylinidae), Contributions to Entomology 74 (1), pp. 13-34 : 13

Somoleptus curtioculatus sp. nov.

Figs 12a-d , 20F

Material examined.

Holotype: MEXICO male; Guerrero; 15 km SW Filo de Caballo ; 2500 m elevation; oak forest (wet) litter; Berlese; 16 July 1992; R.S. Anderson leg.; KNHM #92-011.

Diagnosis.

S. curtioculatus belongs to the Somoleptus longicollis -subgroup due to the bilobed paramere and the triangularly prominent sternite VII of male. Concerning the short eyes and elytra, S. curtioculatus resembles Somoleptus longiceps Irmler, 2022. In comparison to S. longiceps , eyes in S. curtioculatus are much shorter with PS:E ratio 7.8 (in S. longiceps PS:E ratio is 5.4). Moreover, S. curtioculatus is yellow-brown, whereas S. longiceps is black with slightly lighter head and anterior half of pronotum.

Description.

Length: 3.9 mm; Colouration: yellow-brown; abdomen slightly darker; legs and antennae yellow-brown.

Head: 0.62 mm long, 0.47 mm wide; eyes extremely short; PS:E ratio 7.8; posterior angles widely rounded; inter-antennal furrows short; not reaching front edge of eyes; setiferous punctation moderately deep and dense; on average, interstices 1.5 times as wide as diameter of punctures; in apical half with narrow impunctate mid-line; surface without microsculpture; polished; antennae with elongate first antennomere; half as long as total head length; second and third antennomere conical; combined slightly shorter than half-length of first antennomere; following antennomeres at least twice as wide as long; apically increasing in width. Pronotum: 0.72 mm long, 0.45 mm wide; widest at anterior third; strongly narrowed to neck; posteriorly nearly parallel; posterior angles sub-rectangular; setiferous punctation moderately deep and dense; in apical half, denser than on posterior half; on average, interstices between punctures 1-1.5 times as wide as diameter of punctures; wide mid-line impunctate; surface without microsculpture; polished. Elytra: 0.49 mm long, 0.52 mm wide; humeral angles obtuse; sides slightly divergent posteriorly; posterior margin slightly retreated to suture; setiferous punctation moderately deep and dense; on average, interstices between punctures 1.5 times as wide as diameter of punctures; surface without microsculpture; polished. Abdomen with setiferous punctation denser than on elytra, but as deep; posterior margin of sternite VII of male triangularly prominent; posterior margin of tergite VII of male slightly convex: meso- and meta-tibia with one ctenidium each. Aedeagus oval; anteriorly sub-rectangular; dorsal plate covering nearly total central lobe; shortly divided at apex; endophallus with two torsions dividing endophallus in thicker basal part and narrower apical part; basal part with minute teeth; apical part with short lobes; cones at apical orifice short; C:A ratio 0.1; parameres bilobed with slender inner lobe and nearly circular outer lobe; inner lobe with three moderately long setae; outer lobe transparent.

Etymology.

The species name is a combination of the Latin word curtus meaning short and oculus meaning eye and refers to the short eyes.

Geography.

Southern Mexico.

Ecology.

Floor of high montane forests at approximately 2500 m elevation.

Figures

Figure 20. A. Fore-body of Lithocharodes lituratus; B. L. montanus; C. L. parallelus; D. L. zamorae; E. Somoleptus alajuelae; F. S. curtioculatus. Scale bars: 0.5 mm.

Figures 9 - 12. 9. Lithocharodes parallelus; 10. L. zamorae; 11. Somoleptus alajuelae; 12. S. curtioculatus. a. Aedeagus; b. Paramere; c. Sternite VII; d. Tergite VII. Scale bars: 0.5 mm (a, c, d); 0.1 mm (b).