Coelacanthus
Temporal range: Late Permian to Early Triassic
Coelacanthus granulatus fossil
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Sarcopterygii
Class: Actinistia
Order: Coelacanthiformes
Family: †Coelacanthidae
Genus: †Coelacanthus
Agassiz, 1839
Type species
†Coelacanthus granulatus
Agassiz, 1839
Other species

Coelacanthus ("hollow spine") is a genus of extinct coelacanths that first appeared during the Permian period. It was the first genus of coelacanths described, about a century before the discovery of the extant coelacanth Latimeria.[1] The order Coelacanthiformes is named after it.

Description

Coelacanthus bears a superficial similarity to the living coelacanth Latimeria, though it was smaller, and had a more elongated head. Individuals grew up to 0.7 metres (2.3 ft) in length, had an elongate codavypter or supplementary tail lobe, and had small lobed fins, suggesting that Coelacanthus were open-water predators. The fin rays of the caudal fin are hollow, which gave Coelacanthus its name. The name is an adaptation of the Modern Latin cœlacanthus ("hollow spine"), from the Greek κοῖλ-ος (koilos; "hollow") and ἄκανθ-α (akantha; "spine"). These hollow spines are a typical feature of coelacanths.

Restoration of C. granulatus

Distribution and time

The type species Coelacanthus granulatus was described from the late Permian (Wuchiapingian) Kupferschiefer of Germany and equivalent Marl Slate of England. Coelacanthus is primarily known from Late Permian and Early Triassic deposits in Europe and Canada, although the referred species C. welleri, known from Iowa, is of Late Devonian (Famennian) age. It survived the Permian–Triassic extinction event, and one species, C. banffensis, is known from the Early Triassic.

Several other species that were first referred to Coelacanthus were later reallocated to other genera. Coelacanthus minor was considered by Woodward (1891) as potentially belonging to the Triassic genus Heptanema,[2] while Martin and Wenz (1984) considered Coelacanthus lunzensis a possible synonym of Garnbergia.[3] Coelacanthus madagascariensis from the Early Triassic of Madagascar was reattributed to the genus Rhabdoderma, and Coelacanthus evolutus is a synonym of Whiteia woodwardi.[4]

References

  1. ↑ Agassiz, L. 1839. Recherches sur les poissons fossiles II. Petitpierre, Neuchâtel.
  2. ↑ Woodward A. S. 1891. Catalogue of the Fossil Fishes in the British Museum (Natural History). Part II. London.
  3. ↑ M. Martin and S. Wenz. 1984. Découverte d'un nouveau Coelacanthidé, Garnbergia ommata n.g., n.sp., dans le Muschelkalk supérieur du Baden-Württemberg. Stuttgarter Beiträge zur Naturkunde, Serie B (Geologie und Paläontologie) 105:1-17
  4. ↑ Forey P. L. (1998) History of the coelacanth fishes (Chapman & Hall, London).

Mikko's Phylogeny Archive on Coelacanthiformes

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