Abstract

We present the findings of a field survey conducted to study deep soil (=endogean) beetles in Chile. We have analysed 50 soil samples, each weighing about 120 kg, collected from 15 central Chilean forested localities along or near the Coastal Range between Valdivia and Santiago. We illustrate all 2,037 adult specimens of Chilean endogean beetles. These specimens include representatives of 11 families: Carabidae, Corylophidae, Curculionidae (subfamilies Cossoninae, Cyclominae, and Raymondionyminae), an unidentified family of Elateroidea, as well as Eupsilobiidae, Leiodidae, Ptiliiidae, Scarabaeidae, Staphylinidae (subfamilies Aleocharinae, Euaesthetinae, Leptotyphlinae, Osoriinae, Pselaphinae, Scydmaeninae, and Staphylininae), Tenebrionidae, and Zopheridae. The most abundant groups are Leptotyphlinae, Leiodidae and Pselaphinae accounting for 45 %, 17 %, and 17 % of all specimens, respectively. The number of adult endogean beetles per soil sample varied between 1 and 150, with an average of 41 specimens (equivalent to an average of 0.34 specimens per kilogram of soil). For each of the 15 sampled localities, specimens were classified to morphospecies, and for each morphospecies we provide the most accurate identification currently possible, considering that most of the species detected are either unnamed or belong to taxonomically challenging groups. In addition, for each morphospecies and locality at least one specimen was selected to be individually vouchered, DNA extracted, and sequenced for the reference barcode DNA fragment in Metazoa. A total of 190 specimens were selected, obtaining barcode sequences for 187 (98.4% success rate) which are provided in an open access DNA barcode library at BOLD Systems (dx.doi.org/10.5883/DS-VGDS28). Obtained sequences were clustered by BOLD Systems in 119 BINs, all corresponding to unique BINs exclusively formed by the newly generated sequences. In addition, when compared to NCBI databases, sequences yielded no matches with a similarity higher than 97%. The comparison with both, BOLD Systems and NCBI databases, supports that none of the deep soil beetle species here collected in Chile has been previously DNA barcoded. We conclude that the deep-soil beetle fauna of Chile is much richer than previously known and mainly unnamed at the species level.