Trechus oromii Borges, Serrano and Amorim, 2004

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 : 1308-1310

Trechus oromii Borges, Serrano and Amorim , new species

( figure 3 )

Diagnosis

Characterized by the shape of the male aedeagus. Externally very similar to T. picoensis . Integument clearly depigmented, colour reddish testaceous, appendages yellowish. Microreticulation isodiametric in head and pronotum, but transverse in the elytra.

Type series

HOLOTYPE: „, Açores, Faial, Gruta do Capelo, Parque do Capelo , 28 June–18 July 2000 (I. Amorim and F. Pereira). PARATYPE: 1”, same locality as holotype, 26 August–2 September 1999 (I. Amorim and F. Pereira).

Note. In addition four males and six females were collected in the same cave in 2001 for molecular analysis. These are also used for measures.

Description

Length of holotype: 4.82 mm, convex and ovalate, the males being larger than females (average length: 4.64 mm for males and 4.17 mm for females; average width: 1.91 mm for males and 1.70 mm for females).

Head small and narrow as in T. picoensis , narrower than prothorax; eyes small, almost flat; temples with microchaetae and 1.10X broader than eye length (others: 0.86–1.14X). Frons convex, frontal furrows deep and curved; anterior margin of labrum concave; mandibles strong and elongate. Maxillary palpi long and slender. Chaetotaxy: as in T. terrabravensis n. sp. Antennae 3.07 mm (other specimens: 2.55–3.20 mm), reaching backwards for the first quartile of elytra; 3rd antennomere 1.27X longer than 2nd, but quite variable (average 1.44X in males and 1.35X in females); 1st to 3rd antennomere 3.8X longer than wide, 4th to 7th antennomere 3.4X longer than wide, 8th to 10th antennomere 3.0X longer than wide, 11th antennomere 3.3X longer than wide. Pronotum very similar to T. picoensis , convex, transverse, 1.10X as broad as long (others: 1.15–1.21X); side margins curved in front and markedly narrowed backwards in slightly curved lines up to sharp and conspicuous protruding corners; basal margin emarginated and sinuated. Median impression fine but well marked. Basal fovea clearly marked. Chaetotaxy: as in T. terrabravensis n. sp. Elytra ovate, convex with rounded shoulders, 1.90X wider than pronotum (others: 1.70–1.92X) and 1.43X as long as wide (others: 1.42–1.55X). Convex with a depressed anterior field near scutellum. Elytral apex rounded and more depigmented. Chaetotaxy: as in T. terrabravensis n. sp., with setae very long and slender. Legs depigmented, long and slender. Aedeagus apex of median lobe deeply curved upwards in lateral view ( figure 3a ). Basal part of median lobe elongated and not so curved as in T. picoensis . In dorsal view the apex is narrower and longer than in T. picoensis ( figure 3c ).

Ecological notes

The specimens were collected by means of pitfall traps baited with cow or pig liver deep inside of a small lava tube located in Parque do Capelo (Faial). Restricted to Faial.

Taxonomic notes

This new species is clearly similar to the troglobitic species Trechus picoensis that occurs in the nearest island of Pico.

Figures

FIG. 3. Aedeagus of Trechus oromii n. sp. (a) Median lobe, lateral view; (b) left and right parameres; (c) median lobe, dorsal view. Scale: 0.5 mm.