Procynosuchidae is an extinct family of therapsids which, along with
Dviniidae, were the earliest
cynodonts. They appeared around 260 million years ago, and were most abundant during the latest
Permian
The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...
time (251 mya), shortly before the
Permian-Triassic extinction event. Despite being the basal member of the cynodont clade, they already showed some of the advanced mammalian characteristics, but Procynosuchids bore resemblance to the
Therocephalia
Therocephalia is an extinct suborder of eutheriodont therapsids (mammals and their close relatives) from the Permian and Triassic. The therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of their ...
ns.
Procynosuchid eyes are forward-facing, and the
dentary
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
was larger than the Therocephalians. The Procynosuchids had a
secondary palate
The secondary palate is an anatomical structure that divides the nasal cavity from the oral cavity in many vertebrates.
In human embryology, it refers to that portion of the hard palate that is formed by the growth of the two palatine shelves medi ...
, which allows them to eat food while breathing, just like mammals. The Procynosuchids became extinct at the
Permian-Triassic extinction event. Some procynosuchids were
terrestrial
Terrestrial refers to things related to land or the planet Earth.
Terrestrial may also refer to:
* Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
, but others like ''
Procynosuchus
''Procynosuchus'' (Greek: "Before dog crocodile") is an extinct genus of cynodonts from the Late Permian. It is considered to be one of the earliest and most basal cynodonts. It was 60 cm (2 ft) long.
Remains of ''Procynosuchus'' have ...
'' were semi-aquatic.
Prehistoric cynodonts
Prehistoric therapsid families
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