The Hiletini, an ancient and enigmatic tribe of Carabidae with a pantropical distribution (Coleoptera)

Abstract

Abstract. Species of the tribe Hiletini are rarely represented in collections. Of the twenty known species, only three have been adequately collected. These twenty species are here arrayed in two genera, Hiletus (six species in two spe'cies groups), Eucamaragnathus (fourteen species in five species groups). Hiletus species occur in tropical Africa. Eucamaragnathus species of the alluaudi group occur in tropical and southeastern Africa, those of the suberbiei group are found only in Madagascar, those of the bocandei group are found in tropical western Africa, species of the sumatrensis group occur in southeastern Asia (Burma, Vietnam, Sumatra and Borneo), and those of the batesi group are found in the western Amazon Basin, northeastern Amazon Basin, and along the Paraquay River drainage system. Four new species of Hiletini are described from the following type localities: Hiletus nimba, GUINEA, Nimba Mountains; Eucamaragnathus borneensis, BRUNEI, (BORNEO); E.jaws, BRAZIL, Parana; E.amapa, BRAZIL, Territory of Amapa. Most species of Hiletini live in tropical climates with a mean annual temperature above 21°C and mean annual rainfall above 200 cm (exceptions are noted in text). All species apparently frequent latosolic soils in broadleaf evergreen or deciduous forests or in grassland savannahs with scattered or gallery broadleaf evergreen trees. Records available indicate that pupation occurs during the dry season and that adults emerge with the onset of rains. The structure of the mandibles, other mouthparts, crop and proventriculus suggests that only liquid food is normally taken in, and it is probable that at least some preoral digestion occurs as in other carabids. A suite of newly discovered character states associated with the tarsal claws unites the Hiletini with Cnemacanthini, Elaphrini, Migadopini, Promecognathini, Pseudomor‐phini, Scaritini and Siagonini. These stocks together form a sister lineage to the ozaenine‐brachinine lineage, all having distinct epimera, brushy non‐styliform parameres, long empodial unguitractor plates, but not having conjunct mesocoxae (type I). Hiletini is the sister group of the combined Scaritini‐Cnemacanthini‐Pseudomorphini stocks. We suggest that the origin of the Hiletini occurred at least as early as the Jurassic Period from an equatorial position near the centre of the combined Africa/South America landmass. By mid‐Cretaceous, radiation of taxa occurred across southern Laurasia into the southeastern part of that landmass, but never leaving equatorial climates. Later in the Cretaceous or early Tertiary, when continents began their rapid break‐up, hiletines were stranded in tropical parts of South America, Africa/Madagascar, and southeastern Asia where they still occur today.