Furcacauda
| Furcacauda | |
|---|---|
 | |
| Furcacauda fredholmae | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Infraphylum: | Agnatha |
| Class: | †Thelodonti |
| Order: | †Furcacaudiformes |
| Family: | †Furcacaudidae |
| Genus: | †Furcacauda Wilson & Caldwell, 1998 |
| Type species | |
| Furcacauda heintzae | |
| Species | |
| |
Furcacauda is a genus of thelodontid agnathan from the Lower Devonian of Canada, and is the type genus of the order Furcacaudiformes.[2] It contains two species, both of which hail from the MOTH locality in the Mackenzie Mountains of the Northwest Territories.[2]
Furcacaudiform thelodontids were deep water jawless vertebrates with symmetrical fork and lobed-finned tails and scales smaller than typical loganellid and nikoliviid thelodonti scales.[1] 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.[2] Many but not all had laterally paired fins.[2] 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[1] resembling the tail of a heterostracan.[2] 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.[1] 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.[1]
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
[edit]
Furcacauda heintzae
Furcacauda fredholmae
References
[edit]- 1 2 3 4 5 Mark V. H. Wilson; Michael W. Caldwell (1993). "New Silurian and Devonian fork-tailed 'thelodonts' are jawless vertebrates with stomachs and deep bodies". Nature. 361 (6411): 442–444. doi:10.1038/361442a0.
- 1 2 3 4 5 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. Archived from the original on 2010-06-18.
- ↑ Ferrón, Humberto G.; Botella, Héctor (2017). "Squamation and ecology of thelodonts". PLOS ONE. 12 (2) e0172781. Bibcode:2017PLoSO..1272781F. doi:10.1371/journal.pone.0172781. PMC 5328365. PMID 28241029.
- ↑ Ferrón, Humberto G; Martínez-Pérez, Carlos; Turner, Susan; Manzanares, Esther; Botella, Héctor (2018). "Patterns of ecological diversification in thelodonts" (PDF). Palaeontology. 61 (2): 303–315. doi:10.1111/pala.12347. hdl:10550/85568.
External links
[edit]
Media related to Furcacauda at Wikimedia Commons- The Taxonomicon. (2004–2009) Retrieved November 6, 2009.
