Biology:Furcacauda
Furcacauda is a genus of thelodontid agnathan from the Lower Devonian of Canada, and is the type genus of the order Furcacaudiformes.[1] It contains two species, both of which hail from the MOTH locality in the Mackenzie Mountains of the Northwest Territories.[1]
Furcacaudiform thelodontids were deep water jawless vertebrates with symmetrical fork and lobed-finned tails and scales smaller than typical loganellid and nikoliviid thelodonti scales.[2] Furcacaudiform thelodonts are noted as having a laterally compressed body, large anterior eyes, slightly posterior, lateral, and vertical to a small mouth, and a condensed curved row of branchial openings (gills) directly posterior to the eyes.[1] Many but not all had laterally paired fins.[1] Wilson and Caldwell also note the presence of a caudal peduncle and a long caudal fin made of two large lobes, one dorsal and one ventral separated by 8 to 14 smaller intermediate lobes, giving the appearance of a striated half-moon shaped tail[2] resembling the tail of a heterostracan.[1] A large square cavity within the gut connecting a small intestine to an anal opening lead many to believe that it is this genus that exhibits the first vertebrate stomach.[2] According to Wilson and Caldwell, their discovery of sediment infillings of fossils of the Furcacauda heintze fossils gives credence to the evolutionary development of stomach before jaws.[2]
The scales of Furcacauda are robust and abrasion-resistant, similar to modern sharks which live among rough substrates such as rocky caves or reefs.[3][4]
Gallery of species
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Furcacauda heintzae -
Furcacauda fredholmae
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Wilson, Mark V. H.; Caldwell, Michael W. (1998). "The Furcacaudiformes: A New Order of Jawless Vertebrates With Thelodont Scales, Based On Articulated Silurian and Devonian Fossils From Northern Canada". Journal of Vertebrate Paleontology 18 (1): 10–29. doi:10.1080/02724634.1998.10011031. http://www.vertpaleo.org/publications/jvp/18-10-29.cfm.
- ↑ 2.0 2.1 2.2 2.3 Cite error: Invalid
<ref>tag; no text was provided for refs namedWilson1993 - ↑ Ferrón, Humberto G.; Botella, Héctor (2017). "Squamation and ecology of thelodonts". PLOS ONE 12 (2). doi:10.1371/journal.pone.0172781. PMID 28241029. Bibcode: 2017PLoSO..1272781F.
- ↑ Ferrón, Humberto G; Martínez-Pérez, Carlos; Turner, Susan; Manzanares, Esther; Botella, Héctor (2018). "Patterns of ecological diversification in thelodonts". Palaeontology 61 (2): 303–315. doi:10.1111/pala.12347. https://www.uv.es/everlab/PUBLICACIONES/2018/2018%20Ferr%C3%B3n%20et%20al.%20%20Palaeontology%20.pdf.
External links
- The Taxonomicon. (2004–2009) Retrieved November 6, 2009.
Template:Thelodonti Wikidata ☰ Q5509484 entry
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