Protictis

Protictis is an extinct genus of carnivorous mammals known from the late Paleocene and early Eocene of North America. It belongs to the family Viverravidae of the Carnivoramorpha.

Protictis
Temporal range:
Paleocene - Early Eocene
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Order:
Carnivoramorpha
Family:
Viverravidae
Genus:
Protictis

Species
  • P. agastor
  • P. haydenianus (type)
  • P. minor
  • P. paralus
  • P. simpsoni

Fossil founds

Fossils of Protictis are found in the United States and Canada and date mainly from the North American Land Mammal Ages Torrejonian en Tiffanian. The holotype - part of the upper and lowe jaw - were described in 1882 by Edward Drinker Cope based on finds in the San Juan Basin in New Mexico and classified as Didymictis haydenianus. William Diller Matthew described Protictis as a subgenus of Didymictis in 1937 and in 1966 MacIntyre classified it as a separate genus.[1] Protictis means "early weasel" and consists of proto and ictis.

The San Juan Basin is the main location for fossil founds of Protictis. Besides P. haydenianus the species P. simpsoni and P. minor were described based on fossil founds in this area.[2] Of P. simpsoni a skull is found, the earliest known of a member of the Carnivoramorpha.

The other described species are P. agastor from Cedar Point Quarry in Wyoming and P. paralus from Judson in North Dakota. Fossil founds that could not be described at species level are found in Wannagan Creek in North Dakota, Montana, Utah and Alberta. A found in the Willwood Formation is also be assigned to Protictis.

Description

Protictis was a mongoose-like animal that was lightly build.[3] The species had variable sizes. Parts of the skeleton of P. haydenianus are known and this species was about 75 cm long, comparable to the related Didymictis and the modern day Asian civets.[4] The skull of P. simpsoni shows that this species was larger than P. haydenianus. P. minor on the other hand was smaller than P. haydenianus. The morphology of the limb bones of P haydenianus points at a scansorial lifestyle. Protictis had two times as many teeth as modern carnivores. The characteristic carnassials of carnivores were already clearly developed in Protictis, but the long and pointy teeth show that insects were still a major component of this diet. Endocasts of the skull shows that both vision and hearing were important senses, but the position of the eye sockets shows that threedimensional vision was not a good developed as in modern carnivores.[5]

References
  1. Genera and species of Paleocene mammals. Paleocene-mammals.de
  2. New viverravids from the Torrejonian (middle Paleocene) of Kutz Canyon, New Mexico and the oldest skull of the Order Carnivora. TJ Meehan & RW Wilson. Journal Information (2002).
  3. The Evolution of the Mammals. L.B. Halstead. Eurobook Limited (1978).
  4. Postcranial anatomy of Viverravus (Mammalia, Carnivora) and implications for substrate use in basal Carnivora. RE Heinrich & P Houde. Journal of Vertebrate Paleontology (2006).
  5. Carnivores, creodonts and carnivorous ungulates: Mammals become predators
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