''Furcacauda'' is a genus of
thelodont
Thelodonti (from Greek: "feeble teeth")Maisey, John G., Craig Chesek, and David Miller. Discovering fossil fishes. New York: Holt, 1996. is a class (biology), class of extinct jawless fishes with distinctive Fish scale, scales instead of large pl ...
id
agnathan from the Lower Devonian of
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
, and is the type genus of the order
Furcacaudiformes.
Furcacaudiform thelodontids were deep water jawless vertebrates with symmetrical fork and lobed-finned tails and scales smaller than typical loganellid and nikoliviid thelodonti scales.
[ 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.][ Many but not all had laterally paired fins.][ 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][ resembling the tail of a heterostracan.][ 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.][ According
to Wilson and Caldwell their discovery, based on sediment infillings of fossils of the ''Furcacauda heintze'', gives credence to the evolutionary development of stomach before jaws.][
]
Gallery of species
Image:Furcacauda_heintzae.png, ''Furcacauda heintzae''
Image:Furcacauda_fredholmae.png, ''Furcacauda fredholmae''
References
External links
*
The Taxonomicon. (2004–2009)
Retrieved November 6, 2009.
{{Taxonbar, from=Q5509484
Devonian jawless fish
Thelodonti genera
Devonian fish of North America