Systematics of the Relictual Asian Scorpion Family Pseudochactidae Gromov, 1998, with a Review of Cavernicolous, Troglobitic, and Troglomorphic Scorpions

ABSTRACT The first integrative systematic revision of the relictual Asian scorpion family Pseudochactidae Gromov, 1998, making use of an unprecedented collection of material acquired during several expeditions to most of the type localities, is presented. The subfamilies, genera and species of Pseudochactidae are revised based on a phylogenetic analysis of 140 morphological characters and 8608 nucleotide base pairs of concatenated DNA sequence from two nuclear and three mitochondrial gene loci, and a multivariate statistical analysis of 22 ratios and 8 counts for 60 specimens. Three subfamilies, four genera and six species are recognized in the family. Troglokhammouaninae, subfam. nov., is created to restore the monophyly of the nominotypical subfamily Pseudochactinae Gromov, 1998. Aemngvantom, gen. nov., is created to accommodate Aemngvantom lao (Lourenço, 2012), comb. nov., and Aemngvantom thamnongpaseuam gen. et sp. nov. Four new synonyms are presented: Troglokhammouanus louisanneorum Lourenço, 2017 = Troglokhammouanus steineri Lourenço, 2007, syn. nov.; Vietbocap thienduongensis Lourenço and Pham, 2012 = Vietbocap canhi Lourenço and Pham, 2010, syn. nov.; Vietbocap aurantiacus Lourenço et al., 2018 = V. canhi, syn. nov.; Vietbocap quinquemilia Lourenço et al., 2018 = V. canhi, syn. nov. Revised diagnoses of the subfamilies, genera and species, with comparative images, a key and distribution maps are provided, along with a summary of available data on ecology and conservation status, where applicable. Among the Southeast Asian pseudochactids, all of which appear to be obligately cavernicolous, the three species of Vietbocapinae Lourenço, 2012, are highly troglomorphic whereas the sole species of Troglokhammouaninae is barely so. Applying recently revised definitions of the Schiner-Racovitza system for the classification of subterranean organisms, only Vietbocapinae can be considered troglobitic. The global diversity of cavernicolous, troglomorphic and troglobitic scorpions is similarly revisited and a key to ecological classification of cavernicolous and troglomorphic scorpions presented. The world totals of troglomorphic vs. troglobitic scorpions are currently 58 vs. 28 species, in 29 vs. 17 genera and 15 vs. 13 families, respectively.