Achanius (Ambigatus) antofagastensis Flores and Aballay, new species

(Figs. 14–15)

Diagnosis. Antennomere 2 longer than 3, antennomeres 1–5 subcylindrical, antennomeres 6–10 triangular, longer than wide, antennomere 11 equal to 10, pear-shaped; apical maxillary palpomere ovoid, acuminate; prothorax longer than wide, anterior margin of pronotum exceeding width of posterior margin (Fig. 14).

Achanius antofagastensis superficially resembles A. bicolor and A. wittmeri (Fig. 16) in color pattern. It differs from these species by having reduced wings, antennomere 2 longer than 3 and antennomere 11 equal to 10, whereas A. bicolor and A. wittmeri have well-developed wings, antennomere 2 shorter than 3, and antennomere 11 longer than 10. In addition, in A. wittmeri the prothorax is wider than long, and the elytra have an additional triangular dark brown spot pointed backwards between the humeri (Fig. 16).

Description. Length 3.6–4.7 mm. Head and prothorax dark brown, elytra light brown on anterior half and posterior quarter, with dark brown spot on penultimate quarter extending along suture towards apex; antennae, legs, and mouthparts light brown as elytra. One specimen (Fig. 15) with same color pattern but elytra with spot outlined in dark brown. One specimen (Catamarca, 8 km W Antofagasta de la Sierra (16 km W of the holotype locality)) with similar color pattern but head, prothorax, legs, and elytral spot very dark brown. Humeri elevated, wings present, reduced, narrow, reaching 3/4 length of elytra, not folded (Fig. 15); metasternum 3X length of mesosternum; metacoxal width 3X metacoxal length (as in Fig. 20).

Etymology. Named “antofagastensis” after the collection site of Antofagasta de la Sierra, Catamarca province, Argentina.

Type Material. Holotype: Male (Fig. 14): [Argentina: Catamarca, 8 km NE / Antofagasta de la Sierra, Punta de la / Peña 3593 m 26°01′39.54″ S, 67° / 20′38.79″ W, 17-20-XI-2009 / coll. G. Flores, F. Aballay] [ Achanius (Ambigatus) / antofagastensis n. sp. / HOLOTYPUS male/ Det. G. Flores and/ F. Aballay 2015] (IADIZA). Allotype: Female (IADIZA) and four paratypes with the same data as holotype: one male (NHMB), one male (FMNH), one female (MACN), one not sexed (MACN). Paratypes: One male: [Argentina: Catamarca / (Dto.) Antofagasta de la Sierra, 8 km / NE Antofagasta de la Sierra / llama M-4 P-3, 3585 m / 26°01′33.4″ S/ 67°20′42.5″ W, 21-XI-2009 / coll. F. Aballay] (MEKRB); one female with same label information except M-11, 28-XI-2009 (IADIZA) (Fig. 15); one specimen: [Argentina: Catamarca / (Dto.) Antofagasta de la Sierra, 8 km / NE Antofagasta de la Sierra / cerdo al sol M-11 P- 3, 3578 m 26°01′32.3″ S, 67° / 20′36.5″ W, 27-XI-2009 / coll. F. Aballay] (MLPA); one male: [Argentina: Catamarca / (Dto.) Antofagasta de la Sierra, 8 km / NE Antofagasta de la Sierra / cerdo sombra M-17 P- 1, 3595 m 26°01′38.2″ S, 67° / 20′31.6″ W, 03-XII-2009 / coll. F. Aballay] (IADIZA), one specimen with same label information except M-20, 06-XII-2009 without head, not labelled paratype (IADIZA); one specimen: [Argentina: Catamarca 8 km W / Antofagasta de la Sierra, Salar 3434 m / 26°01′54.6″ S, 67°27′07.7″ W / 11-XII-2009 / coll. G. Flores] (IADIZA).

Biology. Specimens collected in the spring at an altitude of over 3,500 m in Antofagasta de la Sierra, Catamarca province, were found feeding on decomposing pig carcasses (12 individuals) and on llama ( Lama glama Linnaeus) carcasses (four individuals). These specimens showed a preference for pig carcasses, nine of which were recorded on the pig carcass in the shade and three under direct sun. This species was associated with the intermediate stages of decomposition (Active Decay and Advanced Decay) defined by Payne (1965). Because of these three behavioral characteristics, this species should be considered for potential forensic importance for estimating time of death (PMI) in arid high environments during the spring.