PACHYCORMIFORMES
PACHYCORMIFORMES
Origins: 184 million years ago (Early Jurassic, Toarcian stage)
Extinction: 66 million years ago (Late Cretaceous, Maastrichtian stage)
Pachycormiforms are an extinct order of marine ray-finned fish that lived in the Jurassic and Cretaceous periods, and only consisted of one family: the Pachycormidae.
Pachycormids were very variable in terms of size, with the smaller ones ranging from 30 centimeters to a meter long, like Euthynotus and Pachycormus, to enormous suspension feeding giants of around 16 meters in length, making them the largest ray-finned fish to have ever lived.
Euthynotus is the most basal of all pachycormids, with the macropredatory genus Pachycormus, which gives the name to the family, is more derived and related with the later suspension feeding forms.
main source: Wikipedia
PHYLOGENY
- Pachycormiformes
- Euthynotus incognitus
- Pachycormus macropterus
- Ohmdenia multidentata
- Saurostomus esocinus
NAME: Euthynotus incognitus
SIZE: Around 30 to 40 centimeters long
DESCRIBED BY: Blainville, 1818
CLOSEST LIVING RELATIVES: Teleocephalans
DEPICTED IN: The Life of a Temnodontosaurus episode 20
Euthynotus incognitus is part of the genus Euthynotus, which is the most basal, or most primitive, of the pachycormids, having lived in the early Toarcian stage of the Early Jurassic.
NAME: Pachycormus macropterus
SIZE: 1 to 1.5 meters long
DESCRIBED BY: Blainville, 1818
CLOSEST LIVING RELATIVES: Teleocephalans
DEPICTED IN: The Life of a Temnodontosaurus episode 12 and The Life of a Teudopsis
Pachycormus macropterus (whose genus comes from the Greek pakhús, meaning "thick" and kormós, meaning "trunk") was found in the seas surrounding Europe, during the Toarcian stage of the Early Jurassic. It grew from 1 to 1.5 meters long. It was a generalist predator, with evidence showing that it could even be a cannibal, with adults eating younger individuals.
NAME: Ohmdenia multidentata
SIZE: 2.5 meters long
DESCRIBED BY: Hauff, 1953
CLOSEST LIVING RELATIVES: Teleocephalans
DEPICTED IN: The Life of a Temnodontosaurus episode 14
Ohmdenia multidentata is the only species of its genus, which lived in the Toarcian stage of the early Jurassic period, and it is a potential missing link between more basal pachycormids and later suspension feeding taxa.
This species is known from just one incomplete fossil, but it is enough to build some notion of its life appearance, showing that it was a long fish with a slender and elongated snout.
Other pachycormids possess thin, needle-like teeth, or large fangs, or instead are totally devoid of teeth, but Ohmdenia is different for having numerous, small backward-facing teeth, implying a diet of soft-bodied cephalopods.
NAME: Saurostomus esocinus
SIZE: 2 meters long
DESCRIBED BY: Gassiz, 1833
CLOSEST LIVING RELATIVES: Teleocephalans
DEPICTED IN: The Life of a Temnodontosaurus episode 15 and The Life of a Teudopsis
Saurostomus esocinus was yet another species of pachycormid that lived in the Toarcian stage of the Early Jurassic, having a characteristic tuna-like shape perfect to attain fast swimming speeds in the water column, to hunt small fish and cephalopods, quite like many other pachycormid species.