Palaeopisthacanthidae Kjellesvig-Waering, 1986

Soleglad, Michael E. & Fet, Victor, 2003, High-level systematics and phylogeny of the extant scorpions (Scorpiones: Orthosterni), Euscorpius 2003 (11), pp. 1-175 : 118-119

Family Palaeopisthacanthidae Kjellesvig-Waering, 1986 – Extinct.

Type Genus. Palaeopisthacanthus Petrunkevitch, 1913 . – Extinct.

Composition. The family includes three genera (Jeram, 1994a, 1994b, 1998; Fet, 2000e): Compsoscorpius , Cryptoscorpius , and Palaeopisthacanthus .

Geological occurrence. Upper Carboniferous of Europe and North America.

Taxonomic history. This family was assigned by Kjellesvig-Waering (1986) to his superfamily “ Scorpionoidea ” in a very broad sense, equivalent to the current infraorder Orthosterni . We emphatically do not include it either in our Scorpionoidea , or in any other extant superfamily or parvorder.

Biogeographic history. Palaeopisthacanthids, the first known orthostern scorpions, inhabited a wet, humid, tropical flood-basin forest (Jeram, 2001). The European and North American Carboniferous record of Palaeopisthacanthidae has no particular biogeographic importance for further evolution of orthostern scorpions. The age of these fossils corresponds to the beginning of Pangea formation, and it was in Pangea for the next 100 Ma in Permian/Triassic that orthostern lineages evolved and dispersed, surviving as four extant parvorders.

Diagnosis. See Kjellesvig-Waering (1986: 232) and Jeram (1994a: 523) for details on the diagnosis of this family.

Discussion. Absence of Carboniferous orthostern fossils from southern continents is due to a much better

representation and knowledge of coal deposits in the northern continents. The exclusively preserved, rich Carboniferous fossils of Europe and North America (Jeram, 2001) include Orthosterni as well as many other scorpion lineages, which did not survive to our time. Palaeopisthacanthids are the sister group to all extant scorpions (Jeram, 1994a; Soleglad & Fet, 2001), and therefore the key taxon for rooting extant groups.