Trechus jorgensis Oromí and Borges, 1991

Borges, P. A. V., Serrano, A. R. M. & Amorim, I. R., 2004, New species of cave-dwelling beetles (Coleoptera: Carabidae: Trechinae) from the Azores, Journal of Natural History 38 (10), pp. 1303-1313 : 1310-1312

Trechus jorgensis Oromí and Borges, 1991 (description of male)

( figure 4 )

Diagnosis

Integument depigmented; antennae with the 2nd antennomere almost as long as 3rd; eyes small and very flat; apical angles of elytra almost straight. Integument depigmented, testaceous; appendages and apex of elytra more yellowish; dorsal surface dull, less shining than the other Azorean species; microreticulation isodiametric but not very precise and granulated.

Studied material

One male, Açores, S. Jorge, Algar das Bocas do Fogo, 30 June–5 August 1999 (I. Amorim and P. A. V. Borges).

Description

Length of male: 3.20 mm (female measured 3.05 mm); width: 1.39 mm (female with 1.23 mm).

Head normal, ovate, frontal furrows deep and curved; frons convex as in previous species, but the orbitals flatter in their anterior part; eyes small, clearly reduced, very flat, the diameter shorter than temples. Labrum less concave than T. terceiranus . Chaetotaxy: as in T. terrabravensis n. sp. Antennae 1.66 mm (1.61 mm in the female), reaching backwards for the first third of elytra; 3rd antennomere almost as long as 2nd; 1st to 7th antennomere 2.0X longer than wide; 8th to 10th antennomere 1.6X longer than wide, 11th antennomere 2.0X longer than wide. Pronotum convex, transverse, 1.27X as broad as long (1.28X in the female). Side margins curved, with a prebasal small sinuation; anterior angles obtuse and rounded; hind angles obtuse with small protruding corners. Base emarginated; lateral fovea not very evident; side marginal furrow narrowly canaliculated; median impression fine. Chaetotaxy: as in T. terrabravensis n. sp. Elytra ovate and convex with shoulders very rounded, as in the female 1.64X wider than pronotum and 1.45X (1.36X in the female) as long as wide. Apical angles forming a right angle, notch not very conspicuous. All striae well marked. Setae long and slender with the typical chaetotaxy of the Trechus spp. Preapical seta closer to the suture than to the apex.

Aedeagus with median lobe moderately arched; apex of the median lobe sharpened and slightly upward curved in lateral view ( figure 4a ). In dorsal view, apical lamina subtruncated ( figure 4c ). Left paramere with four setae and right paramere with five setae ( figure 4b ).

Ecological notes

The specimen was collected by means of pitfall traps baited with cow or pig liver deep inside a volcanic pit. Restricted to S. Jorge.

Taxonomic notes

Female holotype described in Oromí and Borges (1991). This species is clearly similar to the troglobitic species Trechus pereirai n. sp. that occurs in the nearest island of Pico, and the genitalia also with T. terrabravensis n. sp. from the island of Terceira.

Figures

FIG. 4. Aedeagus of Trechus jorgensis Oromí and Borges. (a) Median lobe, lateral view; (b) left and right parameres; (c) median lobe, dorsal view. Scale: 0.3 mm.