Asteracanthus

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Asteracanthus
Temporal range: Bathonian–Valanginian
Complete skeleton and restoration of Asteracanthus ornatissimus from the Solnhofen Limestone
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Hybodontiformes
Family:
Hybodontidae
Genus: Asteracanthus
Agassiz, 1837
Type species
Asteracanthus ornatissimus
Agassiz, 1837

Asteracanthus (from Greek: ἀστήρ aster, 'star' and Greek: ἄκανθα akantha, 'spine')[1] is an extinct genus of hybodont, known from the Middle Jurassic (Bathonian) to the Early Cretaceous (Valanginian).[2]

Description

Dentition of Asteracanthus ornatissimus

Asteracanthus was among the largest known hybodontiforms, reaching a length of 2–3 metres (6.6–9.8 ft). The dentition of Astercanthus is high crowned and multicusped. The low-rounded teeth previously attributed to the genus actually belong to Strophodus. Like Strophodus, the fin spines are covered in tubercles, rather than the ribbing typical of other hybodont fin spines.[2]

Fossil records

The genus as currently circumscribed dates from the Middle Jurassic (Bathonian) to Early Cretaceous (Valanginian) of Europe, including Germany, Switzerland, England and France. A complete skeleton was described in 2021 from the Late Jurassic (Tithonian) aged Solnhofen Limestone. Previously considered synonymous, the genus Strophodus (Middle Triassic-Late Cretaceous) is now considered distinct, with the teeth of Asteracanthus having more in common with Hybodus and Egertonodus.[2]

Ecology

The genus seems to have been adapted for open marine conditions and likely had an epibenthic habit. It was likely a slow swimmer. The teeth are suggested to have been adapted for grasping, with the teeth at the sides of the mouth serving a crushing function. Asteracanthus was probably adapted for feeding on a wide range of prey, ranging from moderately hard shelled to soft-bodied. Teeth of Asteracanthus found with the remains of marine reptiles suggest that it may have also engaged in scavenging.[2]

Taxonomy

Many of the species previously assigned to this genus are now placed in Strophodus, with a 2021 study considering Asteracanthus ornatissimus the only certain species in the genus. The study considered the genus incertae sedis within Hybodontiformes.[2]

References

  1. ^ Roberts, George (1839). An etymological and explanatory dictionary of the terms and language of geology. London: Longman, Orme, Brown, Green, & Longmans. p. 12. Retrieved 12 February 2024.
  2. ^
    ISSN 2056-2799
    .

Further reading

  • L. Agassiz. 1837. Recherches Sur Les Poissons Fossiles. Tome III (livr. 8–9). Imprimérie de Petitpierre, Neuchatel viii-72