Pachycormiformes
Encyclopedia
Pachycormiformes is an extinct order of ray-finned fish
known from Mesozoic
deposits from Eurasia
and the Americas
. They were characterized by having serrated pectoral fins, reduced pelvic fins and a bony rostrum
. Their relations with other fish are unclear.
Some sources place Ichthyodectidae
herein too, but these seem to be somewhat more advanced Teleostei
.
Actinopterygii
The Actinopterygii or ray-finned fishes constitute a class or sub-class of the bony fishes.The ray-finned fishes are so called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines , as opposed to the fleshy, lobed fins that characterize...
known from Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
deposits from Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
and the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
. They were characterized by having serrated pectoral fins, reduced pelvic fins and a bony rostrum
Snout
The snout, or muzzle, is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw.-Terminology:The term "muzzle", used as a noun, can be ambiguous...
. Their relations with other fish are unclear.
Some sources place Ichthyodectidae
Ichthyodectidae
The family Ichthyodectidae was a family of marine actinopterygian fish. Sometimes classified in the primitive bony fish order Pachycormiformes, they are today generally regarded as members of the "bulldog fish" order Ichthyodectiformes in the far more advanced Osteoglossomorpha...
herein too, but these seem to be somewhat more advanced Teleostei
Teleostei
Teleostei is one of three infraclasses in class Actinopterygii, the ray-finned fishes. This diverse group, which arose in the Triassic period, includes 20,000 extant species in about 40 orders; most living fishes are members of this group...
.
Sources/external links
- http://www.courtenaymuseum.ca/paleo/paleo/pachycor.html
- http://www.palaeos.com/Vertebrates/Units/100Neopterygii/100.600.html