Tristychius
Tristychius (from Greek: τρεις treis, 'three' and Greek: στῐ́χος stíkhos 'row')[2] is an extinct genus of elasmobranch chondrichthyan from the Carboniferous period (Visean). Fossils of T. arcuatus, the type and only species, including fin spines have been found in Scotland.
Tristychius Temporal range: Early Carboniferous, | |
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Restoration of Tristychius | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Chondrichthyes |
Order: | †Hybodontiformes |
Family: | †Tristychiidae |
Genus: | †Tristychius Agassiz, 1837[1] |
Type species | |
†Tristychius arcuatus Agassiz, 1837 |
Tristychius was a small animal, up to about 60 centimetres (2 ft) long. It had a heterocercal caudal fin, and large spines on two dorsal fins.[3] Unlike other chondrichthyans that have three basal plates on pectoral fin (propterygium, mesopterygium and metapterygium), its pectoral fin had only two basal plates and lacked mesopterygium.[4] Even through it is one of the earliest known stem-elasmobranchs, it is estimated to be a specialized suction feedeeing benthic predator, either ambushing or using stealth to approach its prey.[5]
References
- L. Agassiz. 1837. Recherches Sur Les Poissons Fossiles. Tome III (livr. 8-9). Imprimérie de Petitpierre, Neuchatel viii-72
- Roberts, George (1839). An etymological and explanatory dictionary of the terms and language of geology. London: Longman, Orme, Brown, Green, & Longmans. p. 174. Retrieved 1 January 2022.
- Dick, John R. F. (1978). "On the Carboniferous shark Tristychius arcuatus Agassiz from Scotland". Earth and Environmental Science Transactions of The Royal Society of Edinburgh. 70 (4): 63–108. doi:10.1017/S0080456800012898. ISSN 2053-5945.
- Coates, Michael I.; Gess, Robert W. (2007). "A New Reconstruction of Onychoselache traqairi, Comments on Early Chondrichthyan Pectoral Gridles and Hybodontiform Phylogeny". Palaeontology. 50 (6): 1421–1446. doi:10.1111/j.1475-4983.2007.00719.x. ISSN 0031-0239.
- Coates, Michael I.; Tietjen, Kristen; Olsen, Aaron M.; Finarelli, John A. (2019-09-06). "High-performance suction feeding in an early elasmobranch". Science Advances. 5 (9). doi:10.1126/sciadv.aax2742. ISSN 2375-2548. PMC 6739094. PMID 31535026.