jaumei group), Microtityus (Microtityus) (in part)], with both femur and chela neobothriotaxic [Microtityus (Microtityus) (in part)], or with only chela neobothriotaxic [Microtityus (Microtityus) (in part, only Microtityus litoralensis Gonzalez-Sponga 2001)]; dentate margin of pedipalp movable fingers composed of 9-12 oblique rows of granules, without accessory granules; tergites with three or five longitudinal carinae; pectines with well developed fulcra; sternum sub-pentagonal; booklung
spiracles ovoid; subaculear tubercle strong and rhomboidal.
Most commonly, these ridges occur on the chelicerae (externally), and are rubbed by the palps; on the booklung
covers, rubbed by the fourth legs; or on the coxae of the first legs rubbed by a peg on the second trochanters (e.
Breathing, or gas exchange, takes place in folded, accordion-pleated, tissue called booklungs
Evidence for terrestriality in mesoscorpions was provided by demonstration of booklungs
in Pulmonoscorpius Jeram, 1994 from early Carboniferous strata of East Kirkton in Scotland (Jeram 1990, 1994).
and a single tracheal spiracle anterior to spinnerets.