Somoleptus densiceps, 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 densiceps sp. nov.

Figs 13a-d , 21A

Material examined.

Holotype: PANAMA male; Chiriqui; 5.6 km N Boquete; La Culebra Trail ; 8°49'23"N, 82°25'18"W; 1450 m elevation; oak forest litter; 19 VI 1996; R. Anderson leg.; KNHM PAN2A96 96-141B.

Diagnosis.

Somoleptus densiceps is part of the Somoleptus longicollis -group due to the brush-like cones of the aedeagus and the shape of sternite VII of male. Amongst the Neotropical Somoleptus species, S. densiceps mostly resembles S. mexicanus Irmler 2022 by the deep and dense punctation, the short eyes and the slightly triangular shape of the head. Parameres are also very similar between both species. In comparison with S. mexicanus , punctation on total fore-body in S. densiceps is much denser, nearly coriaceous.

Description.

Length: 4.0 mm; Colouration: completely black; antennae dark brown, legs lighter brown.

Head: 0.68 mm long, 0.54 mm wide; eyes moderately large; PS:E ratio 3.8; postocular sides slightly divergent; posterior part combined with posterior edge semi-circular; inter-antennal furrows indistinct; setiferous punctation deep and extremely dense; on average, interstices shorter than one fourth of diameter of punctures; at sides, partly coriaceous; in apical part, between eyes with indistinct impunctate mid-line; surface without microsculpture; due to dense punctation scarcely shiny. Antennae with first antennomere elongate; half as long as total head-length; second and third antennomere conical; longer than wide; combined half as long as first antennomere; following antennomere at least twice as wide as long; apically, increasing in width. Pronotum: 0.80 mm long, 0.53 mm wide; widest at anterior third; strongly convergent to neck; posteriorly slightly convergent to sub-rectangular angles; setiferous punctation dense and extremely dense; partly coriaceous; on average, interstices between punctures one fourth as wide as diameter of punctures; wide mid-line impunctate with three single punctures; surface without microsculpture; polished. Elytra: 0.74 mm long, 0.67 mm wide; humeral angles obtuse; sides approximately parallel; posterior angles sub-rectangular; posterior margin slightly retreated to suture; setiferous punctation deep and dense; on average, interstices as wide as half-length of diameter of punctures; surface without microsculpture; shiny. Abdomen with setiferous punctation dense, but much finer than on fore-body; surface without microsculpture; shiny; posterior margin of sternite VII of male slightly triangular with short central knob; tergite VII of male with straight posterior margin; meso-tibia with 5, meta-tibia with 2 ctenidia. Aedeagus oval with sub-rectangular anterior margin; dorsal plate covering nearly total central lobe; endophallus elongate with one torsion; covered by short lobes; cones at apical orifice long; C:A ratio 0.34; paramere bilobed; inner lobe elongate with several long setae at inner edge; outer lobe circular; transparent.

Etymology.

The species name is a combination of the Latin word densus meaning dense and ceps (short form of caput) meaning “head” and refers to the dense punctation of the head.

Geography.

Panama.

Ecology.

Forest floor of montane forests at approximately 1500 m elevation.

Figures

Figure 21. A. Fore-body of Somoleptus densiceps; B. S. guianensis; C. S. luteicornis; D. S. paramocola; E. S. puntarenae; F. S. umicola. Scale bars: 0.5 mm.

Figures 13 - 16. 13. Somoleptus densiceps; 14. S. guianensis; 15. S. luteicornis; 16. S. paramocola. a. Aedeagus; b. Paramere; c. Sternite VII; d. Tergite VII. Scale bars: 0.5 mm (a, c, d); 0.1 mm (b).