Biology:Helodus
Helodus (from Greek: ἧλος helos, 'stud' and Greek: ὀδούς odoús 'tooth')[1] is an extinct genus of cartilaginous fish from the Upper Devonian through Lower Permian.[2] While the type species, H. simplex from the Late Carboniferous (Moscovian ~ 315 million years ago)[3] of England is known from articulated specimens, the rest of the species in this genus are known only from isolated teeth.[4] Over seventy species have been attributed to this genus, many of which may be anterior teeth of other cartilaginous fish. This makes Helodus a wastebasket taxon.[5]: 53–60 Only the type species can be confidently attributed to this genus until articulated remains of other species are found.[4] H. simplex was around 30 centimeters (1 foot) long,[2] and males had a large, tooth-bearing clasping organ on their heads. The teeth of H. simplex, which were arranged in tooth-whorls, were transitional between elasmobranch-like separated teeth and the tooth plates of living chimaeras.[3]
References
- ↑ Roberts, George (1839) (in English). An etymological and explanatory dictionary of the terms and language of geology. London: Longman, Orme, Brown, Green, & Longmans. p. 76. https://archive.org/details/anetymologicala00robegoog. Retrieved 30 December 2021.
- ↑ 2.0 2.1 Arno Hermann Müller: Textbook of paleozoology. Volume III, Vertebrates, Part 1. Gustav Fischer Verlag, 1985.
- ↑ 3.0 3.1 Cohen, Karly E.; Coates, Michael I.; Fraser, Gareth J. (2025). "Teeth outside the jaw: Evolution and development of the toothed head clasper in chimaeras". Proceedings of the National Academy of Sciences 122 (37). doi:10.1073/pnas.2508054122. PMC 12452905. https://www.pnas.org/doi/10.1073/pnas.2508054122.
- ↑ 4.0 4.1 Itano, W.M., Lambert, L.L. A new cochliodont anterior tooth plate from the Mississippian of Alabama (USA) having implications for the origin of tooth plates from tooth files. Zoological Lett 4, 12 (2018). doi:10.1186/s40851-018-0097-8
- ↑ Stahl, Barbara J. (1999). Handbook of Paleoichthyology: Chondrichthyes III, Holocephali. 4. München: Pfeil. ISBN 978-3-931516-63-5.
Template:Holocephali Wikidata ☰ Q1604495 entry
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