Tristichopteridae

Tristichopterids (Tristichopteridae) were a diverse and successful group of tetrapodomorph fishes living throughout the Middle and Late Devonian. They first appeared in the Givetian stage of the Middle Devonian. Within the group sizes ranged from a few tens of centimeters (Tristichopterus) to several meters (Hyneria and Eusthenodon).

Tristichopteridae Temporal range: 392–359 Ma PreꞒ Ꞓ O S D C P T J K Pg N Middle - Late Devonian
Teeth of Platycephalichthys, in CosmoCaixa Barcelona
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Eotetrapodiformes
Family:	†Tristichopteridae Cope, 1889
Genera
See below

Some tristichopterids share some of the features of the elpistostegalians, a paraphyletic assemblage of fishes close to the origin of tetrapods. This mainly concerns the shape of the skull and a reduction in size of the posterior fins.

An old and persistent notion is that Eusthenopteron was able to crawl onto land using its fins. However, there is no evidence actually supporting this idea. All tristichopterids went extinct by the end of Late Devonian.

Genera of Tristichopterids

• Cabonnichthys
• Canningius
• Edenopteron
• Eusthenodon
• Eusthenopteron
• Hyneria
• Jarvikina
• Langlieria
• Mandageria
• Notorhizodon
• Platycephalichthys
• Tristichopterus
• Heddleichthys

Phylogeny

Below is a cladogram modified from Swartz, 2012.[1]

?†Devonosteus proteus Jaekel 1927     ?†Callistipterus clappi     ?†Heddleichthys dalgleisiensis Anderson 1859     ?†Hyneria lindae Thomson 1968     ?†Langlieria socqueti (Clément et al., 2009)     ?†Litoptychius bryanti Vorobyeva 1977     ?†Notorhizodon mackelveyi Young, Long & Ritchie 1992     †Spodichthys buetler Jarvik 1985       †Tristichopterus alatus Egerton 1861       †Eusthenopteron Whiteaves 1881       †Jarvikina wenjukowi (Rohon 1889) Vorobyeva 1977       †Cabonnichthys burnsi Ahlberg & Johanson 1997       †Mandageria fairfaxi Johanson & Ahlberg 1997     †Eusthenodon Jarvik 1952

References

1. Swartz, B. (2012). "A marine stem-tetrapod from the Devonian of Western North America". PLoS ONE. 7 (3): e33683. Bibcode:2012PLoSO...733683S. doi:10.1371/journal.pone.0033683. PMC 3308997. PMID 22448265.

• Ahlberg, PE and Z Johanson (2001). "Second tristichopterid (Sarcopterygii, Osteolepiformes) from the Upper Devonian of Canowindra, New South Wales, Australia, and phylogeny of the Tristichopteridae." in Journal of Vertebrate Paleontology 17:563-673.
• Johanson, Z. and P.E. Ahlberg (1997). "New tristichopterid (Osteolepiformes; Sarcopterygii) from the Mandagery Sandstone (Famennian) near Canowindra, N.S.W., Australia." in Transactions of the Royal Society of Edinburgh 88:39-53.