Somoleptus luteicornis, 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 luteicornis sp. nov.

Figs 15a-d , 21C

Material examined.

Holotype: COSTA RICA male; Puntarenas; Estac. Biol. Las Alturas; 2 km NE; 8°58'26"N, 82°50'4"W; 1720 m elevation; Berlese; leaf litter; 21 Jun 1998; R. Anderson leg.; KNHM CR1A98 106.

Paratypes: COSTA RICA 1 male ; 1 female; San José; km 117 Pan-Am Hwy. ; 19 km N San Isidro; 9°28'0"N, 83°42'20"W; 1800 m elevation; Berlese; forest litter; 25 Jun 1997; R. Anderson leg.: KNHM CR1A97 035A ; 2 females; Alajuela; E.B. San Ramon; R.B. San Ramon ; 27 km N and 8 km W San Ramon; 10°13'30"N, 84°35'30"W; 960 m elevation, Berlese; forest litter, 14 Jun 1997, leg. R. Anderson (CR1A97 014A) (KNHM) ; 1 female; Guanacaste; Patilla Biological Station ; 10°59'22"N, 85°25'33"W; 610 m elevation; flight intercept trap; 13-15 Jun 2000; J. Ashe, R. Brooks, Z. Falin leg.; KNHM CR1ABF00 135 .

Diagnosis.

The species belongs to the Somoleptus longicollis -subgroup due to the structure of the aedeagus and the sternite VII of male with long central spine. According to the shape of the head and the proportion of the elytra, S. luteicornis resembles S. punctulatus Sharp, 1885, but the colouration is different. Somoleptus luteicornis is totally black, whereas the pronotum of S. punctulatus is lighter reddish-brown. It differs also by the yellow antennomeres IV to XI contrasting with the dark basal three antennomeres. In S. punctulatus , the antennomeres are totally yellow. Moreover, the apical cones at the orifice of the aedeagus are longer in S. luteicornis with C:A ratio of 0.3, whereas the ratio is 0.15 in S. punctulatus .

Description.

Length: 3.89 mm; Colouration: completely black including legs and base of antennae; antennomeres IV to XI contrasting yellow from the three basal antennomeres.

Head: 0.67 mm long, 0.49 mm wide; eyes slightly prominent; moderately large; PS:E ratio 3.5; postocular sides nearly parallel; posterior angles sub-rectangular; setiferous punctation deep and dense; on average, interstices between punctures half as wide as diameter of punctures; small spot at posterior head more sparsely punctate; surface without microsculpture; polished; antennae with first antennomere elongate; slightly longer than half-length of head; second and third antennomere longer than wide; conical; combined half as long as first antennomere; following antennomeres wider than long; anteriad increasing in width. Pronotum: 0.75 mm long, 0.44 mm wide; widest at anterior third; conically narrowed to neck; posteriad, sides slightly convergent to sub-rectangular posterior angles; posterior margin convex; setiferous punctation deep and dense; on average, interstices between punctures 0.8 times as wide as diameter of punctures; wide mid-line impunctate; surface without microsculpture; polished. Elytra: 0.78 mm long, 0.66 mm wide; humeral angles obtuse; sides nearly parallel; posterior angles sub-rectangular; posterior margin convex; retreated to suture; setiferous punctation deep and dense; irregular; close to suture nearly coriaceous; laterally, on average, interstices between punctures as wide as diameter of punctures; meso- and meta-tibia with 3 ctenidia each. Abdomen with setiferous punctation finer, but denser than on elytra; sternite VII of male with long triangularly prominent posterior margin; posterior margin of tergite VII of male convex. Aedeagus long oval; dorsal plate covering nearly total central lobe; endophallus with one torsion; central part of endophallus straight covered by distinct lobes; cones at apical orifice long; C:A ratio 0.38; paramere bilobed; outer transparent lobe reniform; inner elongate lobe slender with several setae at outer edge.

Etymology.

The species name is a combination of the Latin words luteus meaning “yellow” and cornu meaning the antennae of insects and refers to the yellow antennomeres IV to XI.

Geography.

Costa Rica.

Ecology.

Floor of montane and cloud forest of 500 to 1500 m elevation in June.

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).