Asteracanthus

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

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

See text

Description
Dentition of Asteracanthus ornatissimus
Single lateral tooth of A. ornatissimus (from Agassiz's collection at Muséum d'histoire naturelle de Neuchâtel)
Single mesial teeth of A. ornatissimus (from Agassiz's collection at Muséum d'histoire naturelle de Neuchâtel)

Asteracanthus was among the largest known hybodontiformes, reaching a length of 2–3 metres (6.6–9.8 ft). The dentition of Astercanthus is high crowned and multicusped.[2]

Fossil records

This genus has been reported from the Middle Triassic to the Cretaceous, though the genus as currently circumscribed dates from the Bathonian-Valanginian, predominantly of Europe.[2] Fossils are found in the marine strata of United States, Iran, Switzerland, Madagascar, Morocco and Europe. A complete skeleton was described in 2021 from the Late Jurassic (Tithonian) aged Solnhofen Limestone.[2] 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]

Life habits

The genus seems to have been adapted for open marine conditions and likely had an epibenthic habit.[2]

Species

Species within this genus include:[3]

  • Asteracanthus acutus Agassiz 1837
  • Asteracanthus aegyptiacus Stromer, 1927[4]
  • Asteracanthus granulosus Egerton 1854
  • Asteracanthus magnus Agassiz 1838
  • Asteracanthus medius Owen 1869
  • Asteracanthus minor Agassiz 1837
  • Asteracanthus ornatissimus Agassiz 1837
  • Asteracanthus papillosus Egerton 1854
  • Asteracanthus semisulcatus Agassiz 1837
  • Asteracanthus siderius Leidy 1870
  • Asteracanthus somaensis Yabe 1902
  • Asteracanthus tenuis Agassiz 1838
  • Asteracanthus udulfensis Leuzinger et al. 2017[5]

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 29 December 2021.
  2. Stumpf, Sebastian; López‐Romero, Faviel A.; Kindlimann, René; Lacombat, Frederic; Pohl, Burkhard; Kriwet, Jürgen (2021-01-13). Cavin, Lionel (ed.). "A unique hybodontiform skeleton provides novel insights into Mesozoic chondrichthyan life". Papers in Palaeontology. 7 (3): 1479–1505. doi:10.1002/spp2.1350. ISSN 2056-2799.
  3. Paleobiology Database
  4. Ibrahim, Nizar; Sereno, Paul C.; Varricchio, David J.; Martill, David M.; Dutheil, Didier B.; Unwin, David M.; Baidder, Lahssen; Larsson, Hans C. E.; Zouhri, Samir; Kaoukaya, Abdelhadi (2020-04-21). "Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco". ZooKeys (928): 1–216. doi:10.3897/zookeys.928.47517. ISSN 1313-2970. PMC 7188693. PMID 32362741.
  5. Léa Leuzinger; Gilles Cuny; Evgeny Popov; Jean-Paul Billon-Bruyat (2017). "A new chondrichthyan fauna from the Late Jurassic of the Swiss Jura (Kimmeridgian) dominated by hybodonts, chimaeroids and guitarfishes". Papers in Palaeontology. 3 (4): 471–511. doi:10.1002/spp2.1085.
  • L. Agassiz. 1837. Recherches Sur Les Poissons Fossiles. Tome III (livr. 8–9). Imprimérie de Petitpierre, Neuchatel viii-72
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