Trechus pereirai 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 : 1306-1308

Trechus pereirai Borges, Serrano and Amorim , new species

( figure 2 )

Diagnosis

Elytra and pronotal disc slightly pigmented; elytra apical angles almost straight. Eyes reduced. Elytra and pronotal disc slightly pigmented; appendages depigmented. Microreticulation isodiametric, though not very clear. In general darker than T. picoensis , T. jorgensis and T. oromii .

Type series

HOLOTYPE: „, Açores, Pico, Gruta do Tio Joaquim, Ribeirinha , 29 June–16 July 2000 (I. Amorim and F. Pereira). PARATYPE: 1”, Açores, Pico , Gruta das Cabras ( Terra ), Terra do Pão , S. Caetano , 18–25 August 2001 (I. Amorim and F. Pereira).

Note. In addition three males and one female were collected in Gruta das Cabras (Terra) for molecular analysis. These are also used for measures.

Description

Length of holotype: 3.20 mm. Length of other specimens: 3.02–3.19 mm. Small, convex and ovalate.

Head normal, ovate, frontal furrows deep and curved; frons convex as in the other Azorean Trechus , but the orbitals flatter in their anterior part; eyes small and reduced, slightly convex, the diameter as long as temples. Temples curved as in T. jorgensis . Labrum arcuated. Maxillary palpi long and slender. Chaetotaxy: as in T. terrabravensis n. sp. Antennae 1.76 mm long (others: 1.68–1.79 mm), reaching backwards for the first quartile of elytra; 2nd antennomere almost as long as 3rd; 1st to 7th antennomere 1.8X longer than wide, 8th to 10th antennomere 1.6X longer than wide, 11th antennomere 2.0X longer than wide. Pronotum convex, transverse, 1.21X as broad as long (others: 1.24–1.29X); side margins curved with a prebasal small sinuation; anterior angles obtuse and slightly rounded; hind angles obtuse with small protruding corner. Median impression fine but well marked. Base emarginated with basal fovea clearly marked. Chaetotaxy: as in T. terrabravensis . Elytra ovate, convex with shoulders very rounded, 1.68X wider than pronotum (others: 1.60–1.66X) and 1.37X as long as wide (others: 1.36–1.42X). Apical angles almost sharp angled as in T. jorgensis ; notch not very conspicuous. All striae well marked, with interstriae slightly convex. Chaetotaxy: as in T. terrabravensis , with setae very long and slender. Legs depigmented, similar to T. jorgensis , with protibiae not carinated; male protarsus with first two segments dilated. First metatarsomere 1.4X as long as onychium. Aedeagus with apex of median lobe more or less straight and pointed (lateral view) ( figure 2a ); apex subtruncated (dorsal view) ( figure 2c ). Left and right parameres with four setae each ( figure 2b ).

Ecological notes

The specimens were collected by means of liver-baited pitfall traps deep inside two small lava tubes, one located in the northeasternmost part of Pico island (Gruta do Tio Joaquim) and the other located in the central southern part of the island (Gruta das Cabras, Terra). Known from Pico island only.

Taxonomic notes

This new species is clearly similar to the troglobitic species T. jorgensis that occurs in the northwards close island of S. Jorge.

Figures

FIG. 2. Aedeagus of Trechus pereirai n. sp. (a) Median lobe, lateral view; (b) left and right parameres; (c) median lobe, dorsal view. Scale: 0.3 mm.