A review of fossil scorpion higher systematics

 

The Scorpion Files doesn't include fossil scorpion taxa. I know this has been wanted by some, but so far I haven't had capacity to do this. Very recently, Jason Dunlop and Russell Garwood have published an impressive and thorough review of the higher systematics of fossil scorpions.

This paper has a detailed account of the history and development of fossil scorpion taxonomy. It also sums up today's status and comments on future research needs for this important area. A list of all currently known taxa is presented in an appendix. An analysis merging fossil and extant higher systematics is one of the tasks that will improve our understanding of scorpion evolution and systematics.

Abstract:
Scorpions (Arachnida: Scorpiones) are a diverse and widespread arachnid order with a rich and deep fossil record. Here we review the, sometimes complex, historical development of fossil scorpion higher classification. We present a chronological account of family and genus names, together with an overview of higher taxa as potential clade names. In 1884 Thorell & Lindström divided scorpions based on whether the legs were short and pointed (Apoxypoda) or ended in paired claws (Dionychopoda). Pocock in 1911 used the morphology of the ventral mesosomal sclerites, which could either be bilobed (Lobosterni) or of a modern configuration (Orthosterni). Petrunkevitch in 1949 attached importance to a putative first
opisthosomal tergite being present (Protoscorpionina) or absent (Euscorpionina). Kjellesvig-Waering in 1986 recognised four major groups (Holosternina, Meristosternina, Lobosternina and Bilobosternina) based on the shape of the ventral
mesosomal sclerites. The Stockwell/Jeram schemes from the 1980s and 1990s proposed a cladistic progression from early branching lineages, for which the names Protoscorpiones and Palaeoscorpiones were used, towards Scorpiones sensu stricto defined by the presence of book lungs and coxapophyses. Scorpiones was further divided into Mesoscorpionina and Neoscorpionina. Neoscorpions were characterised by a reduced number of lateral eye lenses and comprise the paleosterns, with
marginal lung spiracles, and orthosterns with spiracles in the middle of the sternite. We briefly discuss the merits of these alternatives and present a summary of the current higher classification of scorpions. Forty-three extinct family groups are
currently recognised, and of the 24 living families seven have fossil representatives. Including incertae sedis taxa, there are 76 extinct genera and five extant genera with fossil representatives. Both modern parvorders, Buthida and Iurida, were potentially
present in the Triassic. Buthidae, Chaerilidae, Chactidae and perhaps Hormuridae have been reported from the Cretaceous. Euscorpiidae are known from the Palaeogene and Scorpionidae has potential (but unconfirmed) records from the
Neogene. Given the complexity of this history and the present taxonomy of the group, we hope this contribution provides a first step towards simplifying fossil scorpion systematics.

Reference:
Dunlop JA, Garwood RJ. A review of fossil scorpion higher systematics. PeerJ. 2024;12:e18557. [Open Access]