Canoes
| Canoes | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||||
| Middle Miocene | ||||||||||||
| 14 million years | ||||||||||||
| Locations | ||||||||||||
|
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Canoes | ||||||||||||
| Dehghani & Werdelin , 2008 | ||||||||||||
Kanuites is an extinct genus of crawling cats thatlivedin Africa in the Middle Miocene . It is only known from a few fossilsthat were discoveredin Fort Ternan in Kenya. The only recognized species is Kanuites lewisae . Both species and genus received their first scientific description in 2008, but the genus name Kanuites was already in use before that. Possibly the animals lived as omnivores comparable to today's gorse cats .
features
So far, individual skull and dentition remains as well as isolated teeth have been found from canoes . The holotype skull belongs to a fully grown individual and measured 15 cm in length. He was very flat and built relatively narrow with long nasal bones that reached to the front edge of the orbit . Also was agent jawbone slim, he ended up at the level of the second premolar on the parietal bones , a lower rose head crest , the somewhat ansetzte behind the eye window and back to the projection of the occipital bone went where both easily hung the skull. The eye window was almost completely formed by the frontal bone , only the palate on the abdomen and the sphenoid on the back had certain parts. A large tear-nasal canal opened in the eye socket, the tearbone itself was higher than it was wide. The lower jaw was long and slender, the deepest point of the horizontal bone body was reached under the first molar . A mental foramen was located below the second premolar. The ascending branch was low. The articular process protruded backwards and was slightly inclined to the longitudinal axis of the lower jaw. The angular process was large. Its rear end was approximately level with the articular process.
From the dentition, the row of teeth from the second premolar to the first molar ( P 2- M 1) on the left and from the canine to the last premolar ( C- P4) on the right on the holotype skull . It also contains all the alveoli of the incisors , as well as those of the left canine and the first premolar and the right first molar. The alveoli of each of the second molars are missing, but the corresponding teeth are found on individual upper jaw fragments. Various lower jaw parts are available for the lower dentition, but these largely belong to young animals and also do not reveal the complete row of teeth. The tooth formula for the upper dentition is: I? 3-C1-P4-M2. The canine was built relatively simply and had a cutting surface on the front and back, which, however, was not very raised. The diastema to the anterior premolar reached a length of 1.5 mm. The foremost premolar tooth itself was small and built like a stake. The rear ones, which in turn were separated from the front by a gap in their teeth, then increased in size, the last one was very robust. This represented the upper part of the scissor bite . In contrast to the two-rooted anterior premolars, it had three roots. Under the main cusps of the occlusal surface, the protoconus was extremely large. The actual scissors existed between the paraconus and the metastyle, a shear edge. The following first molar was triangular in shape, the narrower edge of the triangle taking the cheek side of tooth one. The trine formed a shallow basin that was framed by the three main bumps. The tongue-side protoconus was noticeably large, the paraconus stood directly opposite it on the cheek side, while the somewhat smaller metaconus protruded at the end of the tooth. Only a few permanent teeth of the lower dentition have so far been occupied. the first premolar was small and separated from the rear teeth through a gap. As is common in predatory animals, the counterpart to the posterior upper premolar in the crushing shears was the lower first molar. This was short and wide, the trigonid with the three main bumps took up 60% of the total length of the tooth. Of the three main humps, the protoconid had the greatest height. The para- and metaconid were about the same size, the angle with the shear surfaces between the two cusps was 63 °. On the short and wide talonid there were three smaller knolls, of which the hypoconid was the largest. The other two comprised the entoconid and the hypoconulid, the latter located at the furthest point of the tooth and was very small.
Fossil finds
Fossils of kanuites are very rare. The only known material so far comes from Fort Ternan around 65 km east of Kisumu in western Kenya . The important fossil deposit belongs to the East African Trench . The geological sequence consists of a series of volcanic deposits that filled a former basin at the foot of a volcano, the Tinderet . Some of these tuffs weathered to form soil formations that contain the fossils. The layers are known as Fort Ternan Beds and reach a thickness of 60 m and more. Of the three paleo soils (A to C), however, only the middle one is fossil-bearing. In the course of the formation of the Great African Rift Valley , the basin lifted out as a host clod and eroded. The paleo-soils, which are rich in finds, are therefore spatially very limited. Radiometric dates indicate the origin of the layers in the Middle Miocene with absolute age values of 13.7 to 13.8 million years.
The first Fundein Fort Ternan was discovered by a local farmer who informed Louis Leakey and his wife Mary Leakey . They then examined the site between 1959 and 1967, documenting more than 10,000 fossil finds. Among other things, the remains of Kenyapithecus are important . In addition, the rich fauna includes a wide variety of artifacts and odd-toed ungulates as well as rodents , elephants and predators or hyaenodonta . Other remains concern birds and reptiles. The predators of Fort Ternan are very diverse. Representatives of the Amphicyonidae , the Barbourofelidae , the Percrocutidae and the Viverridae are proven . To kanuites been a total of three skulls are found, two of which represent young animals. There are also individual upper and lower jaw parts and isolated teeth.
Paleobiology
Kanuites was about the size of today's gorse cats and weighed less than 10 kg. Due to the generalized structure of the skull and the molars, especially the first molar, it is assumed that Kanuites also resembled genet cats in their behavior and, like them, was presumably a rather omnivorous animal, but had a stronger tendency to eat meat. It is unclear whether the small predator like the gorse cats could also move in trees (arboreal way of life) due to the lack of postcranial skeletal material.
Systematics
The genus Kanuites was scientifically described for the first time in 2008 by Reihaneh Dehghani and Lars Werdelin . The shape is based on a nearly complete skull of a fully grown animal, only missing the zygomatic arches and individual parts of the skull base (copy number KNM-FT 8747). It represents the holotype ; further material used for the first description consists of a fragment of the upper jaw and isolated teeth. So far the only recognized species is Kanuites lewisae . The generic name Kanuites goes back to the Swahili word canoe and means "little carnivore". The species name lewisae honors Margaret E. Lewis and her services to research into African predators. The designation Kanuites is based on a designation by Robert JG Savage and Michael R. Long , which they used for the first time in 1986, but it was considered a noun nudum . At that time the name included all the remains of small felids from Fort Ternan, which can be assigned to a total of three different species. These fossils also include remains of the trunk skeleton and limbs, as well as finds from juvenile individuals.
Within the superfamily Feloidea, only a provisional integration to the crawling cats was made, which is due to the small amount of finds. The genus Herpestides , which partly belongs to the early Miocene , but also Africanictis and Stenoplesictis belong to the closer relationship .
literature
- Reihaneh Dehghani and Lars Werdelin: A new small carnivoran from the Middle Miocene of Fort Ternan, Kenya. New Yearbook on Geology and Paleontology, Abhandlungen 248 (2), 2008, pp. 233–244.
- Lars Werdelin: Middle Miocene Carnivora and Hyaenodonta from Fort Ternan, western Kenya. Geodiversitas 41 (6), 2019, pp. 267–283.
- Lars Werdelin and Stephane Peigné: Carnivora. In: Lars Werdelin and William Joseph Sanders (eds.): Cenozoic Mammals of Africa. University of California Press, Berkeley, Los Angeles, London, 2010, pp. 603-657 (p. 622).
Individual evidence
- ↑ a b c d e f Reihaneh Dehghani and Lars Werdelin: A new small carnivoran from the Middle Miocene of Fort Ternan, Kenya. New Yearbook on Geology and Paleontology, Abhandlungen 248 (2), 2008, pp. 233–244.
- ^ A b c Lars Werdelin: Middle Miocene Carnivora and Hyaenodonta from Fort Ternan, western Kenya. Geodiversitas 41 (6), 2019, pp. 267–283.
- ^ A b Lars Werdelin and Stephane Peigné: Carnivora. In: Lars Werdelin and William Joseph Sanders (eds.): Cenozoic Mammals of Africa. University of California Press, Berkeley, Los Angeles, London, 2010, pp. 603-657 (p. 622).
- ↑ a b Pat Shipman, Alan Walker, John A. Van Couvering, Paul J. Hooker and JA Miller: The Fort Ternan Hominoid site, Kenya: Geology, Age, Taphonomy and Paleoecology. Journal of Human Evolution 10, 1981, pp. 49-72.
- ↑ Martin Pickford, Yoshihiro Sawada, Ryoichi Tayama, Yu-ko Matsuda, Tetsumaru Itaya, Hironobu Hyodo and Brigitte Senut: Refinement of the age of the Middle Miocene Fort Ternan Beds, Western Kenya, and its implications for Old World biochronology. Comptes Rendus Geoscience 338 (8), 2006, pp. 545-555.
- ^ Robert JG Savage and Michael R. Long: Mammal Evolution: An Illustrated Guide. London, 1986, pp. 1-259 (p. 80).