The oldest short-tailed whipscorpion (Schizomida): a new genus and species from the Upper Cretaceous amber of northern Myanmar

Abstract

Arachnids are an ancient lineage of arthropods and orders such as scorpions, harvestmen and mites have their fossil origins in the Silurian or Devonian. Another order with potentially old origins is the short-tailed whipscorpions, or schizomids (Arachnida: Schizomida). These animals have a fragmentary fossil record with species either described or documented from Dominican amber (Miocene: Chattian), drill core sediments from the Oligocene in China, and the upper Pliocene (Zanclean) of Arizona. Here, we describe the first named example of a short-tailed whipscorpion from Late Cretaceous amber (Myanmar: Hukawng Valley) based on male morphological features. Mesozomus groehni gen. et sp. n. cannot be assigned to any Recent genera of schizomids and preserves a unique mix of plesiomorphic (e.g. the retention of eyes) and apomorphic characters (e.g. enlarged femur IV) that merit future evaluation within a phylogenetic context. We extend the fossil record of schizomids by ca. 65 million years, from the Paleogene to the Mesozoic, and add the twelfth order of arachnids to the diverse arachnid biota documented from Burmese amber.