Mixopteridae

Mixopteridae Temporal range: early Silurian, 443.8–416 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossil of Mixopterus kiaeri exhibited at the Moscow Paleontological Museum.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Order:	†Eurypterida
Infraorder:	†Diploperculata
Superfamily:	†Carcinosomatoidea
Family:	†Mixopteridae Caster & Kjellesvig-Waering, 1955
Type species
†Mixopterus multispinosus Ruedemann, 1921
Genera
Lanarkopterus Mixopterus Terropterus
Synonyms
Lanarkopteridae Tollerton, 1989

The Mixopteridae are a family of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". The family is one of two families contained in the superfamily Carcinosomatoidea (along with Carcinosomatidae), which in turn is one of the superfamilies classified as part of the suborder Eurypterina.

According to a 2024 paper, this family may be paraphyletic, containing modern scorpions.[1] However, the vast majority of phylogenetic analyses classify scorpions as arachnids, not eurypterids, making this claim unlikely.[2]

Description

Mixopterids were characterized by large exoskeletons with scattered tubercles or semicircular scales. The prosoma (head) was subquadrate, protruding antemedially. The chelicerae (claws in front of the mouth) were small. The first two pairs of walking legs were strongly developed, with long paired spines. The third and fourth walking legs were moderately sized, with short spines. The preabdomen, the front portion of the body, was narrow with axial furrows, while the postabdomen was narrow. The telson was a curved spine.[3]

Genera

• Order Eurypterida Burmeister, 1843
• Superfamily Carcinosomatoidea Burmeister, 1845

  Family Mixopteridae Caster & Kjellesvig-Waering, 1955

  Genus Mixopterus Ruedemann, 1921

  Genus Lanarkopterus Størmer, 1936

  Genus Terropterus Wang et al., 2021

See also

• List of eurypterids

References

1. Braddy, Simon J. (14 September 2024). "Carcinosomatoid eurypterid palaeoecology and phylogeny: ichnology and palaeocommunities". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 312 (2): 167–181. doi:10.1127/njgpa/2024/1206.
2. Waggoner, B. M. (12 October 1999). "Eurypterida: Morphology". University of California Museum of Paleontology Berkeley. Archived from the original on 23 October 2020. Retrieved 20 October 2020.
3. Størmer, L 1955. Merostomata. Treatise on Invertebrate Paleontology, Part P Arthropoda 2, Chelicerata, P34-P35.