Praearcturus
{{Short description|Extinct genus of arthropod}}
{{Speciesbox
| fossil_range = {{Fossil range|Lochkovian|latest=Famennian}}
| image = Praearcturus sp. YPM IP 097410.jpg
| image_caption = Praearcturus sp.
| taxon = Praearcturus gigas
| authority = Woodward, 1871
| parent_authority = Woodward, 1871
| synonyms =
- Bennettarthra annwnensis? {{small|Fayers, Trewin & Morrissey, 2010}}
}}
Praearcturus is an extinct genus of arthropod, most likely a scorpion, known from the Devonian period of what is now Britain. It is the only genus in the family Praearcturidae and contains the single species P. gigas.
Taxonomic history
The type fossil was discovered in Rowlestone, England, and was described as a giant isopod in 1871 by Henry Woodward.{{Cite web|title=Mindat.org|url=https://www.mindat.org/taxon-6893146.html|access-date=2021-12-28|website=www.mindat.org}}{{cite journal|first=H.|last=Woodward|year=1871|title=On the remains of a giant isopod Praearcturus gigas (H. Woodward) from the Old Red Sandstone of Rowlestone quarry, Herefordshire|journal=Transactions of the Woolhope Field Naturalist's Club|volume=1870|pages=266–270}} It was later interpreted as a scorpion by Rolfe (1980), who claimed that it was based on the personal communications by L. Størmer (1974) and E. N. Kjellesvig-Waering (1978) and the published figures by Rolfe (1969).{{cite book |last=Rolfe |first=W.D.I. |year=1980 |editor=Panchen, A.L. | chapter=Early Invertebrate Terrestrial Faunas |title=The Terrestrial Environment and the Origin of Land Vertebrates |chapter-url=https://exuvium.net/wp-content/uploads/2022/12/early-invertebrate-terrestrial-faunas-rolfeian_w_d.pdf |publisher=Academic Press |volume=Systematics Association Special 15 |pages=117-157}} While type specimen is from the Lower Devonian of Old Red Sandstone,{{cite journal |last=Kjellesvig-Waering |first=E. N. |year=1986 |title=A restudy of the fossil Scorpionida of the world |journal=Palaeontographica Americana |volume=55 |pages=1–287 |url=https://www.biodiversitylibrary.org/item/91625#page/126/mode/1up}} single tergite remain is known from Lower Devonian of Wyoming and fragmentary cuticles referrable to this genus is known from Famennian of Portishead.{{Cite journal |last1=Lamsdell |first1=James C. |last2=Braddy |first2=Simon J. |last3=Tetlie |first3=O. E. |date=2009 |title=Redescription of Drepanopterus abonensis (Chelicerata: Eurypterida: Stylonurina) from the late Devonian of Portishead, UK |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2009.00902.x |journal=Palaeontology |language=en |volume=52 |issue=5 |pages=1113–1139 |doi=10.1111/j.1475-4983.2009.00902.x |bibcode=2009Palgy..52.1113L |s2cid=129243775|url-access=subscription }} Based on comparisons to modern scorpions, the species could have reached a total length of nearly {{convert|1|m|ft}}, possibly making it one of the largest scorpions known.{{cite journal|last1=Dunlop|first1=J. A.|last2=Selden|first2=P. A.|year=2013|title=Scorpion fragments from the Silurian of Powys, Wales|journal=Arachnology|volume=16|issue=1|pages=27–32|url=http://www.paulselden.net/uploads/7/5/3/2/7532217/silurianscorpion.pdf|doi=10.13156/arac.2013.16.1.27|s2cid=128679832}}
However, a 2024 study was uncertain whether Praearcturus could be identified as a scorpion, due to the fragmentary material showing no definitive features of scorpions and arachnids.{{Cite journal |last1=Dunlop |first1=Jason A. |last2=Garwood |first2=Russell J. |date=2024-12-06 |title=A review of fossil scorpion higher systematics |url=https://peerj.com/articles/18557/ |journal=PeerJ |language=en |volume=12 |pages=e18557 |doi=10.7717/peerj.18557 |doi-access=free |issn=2167-8359|pmc=11627080 }} Braddy (2024) also questioned its identity as a scorpion and considered that the original interpretation as a crustacean is more likely, with the supposed pedipalp (claw) of a scorpion more likely being a cheliped of a crustacean. He further supported his argument based on the "grooves and pustular ornament on its carapace and cheliped, and recurved first tergum", and suggested that Bennettarthra could be synonymous with Praearcturus as both taxa show similar morphological features.{{Cite journal|last=Braddy |first=S. J. |title=Carcinosomatoid eurypterid palaeoecology and phylogeny: ichnology and palaeocommunities |year=2024 |journal=Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen |volume=312 |issue=2 |pages=167–181 |doi=10.1127/njgpa/2024/1206 }} In a 2024 conference abstract, however, it was noted that a redescription of Praearcturus is in preparation, which the authors claim confirms the genus' scorpion identity.{{cite conference|author1=Howard, Richard J.|author2=Edgecombe, Gregory D.|author3=Legg, David A.|year=2024|title=A revision of Praearcturus gigas and a critical review of Palaeozoic scorpion gigantism|conference=The Palaeontological Association 68th Annual Meeting|page=60|url=https://www.palass.org/sites/default/files/media/annual_meetings/2024/abstracts%202024.pdf}}