Micropithecus leakeyorum
| Micropithecus leakeyorum | ||||||||||||
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| Temporal occurrence | ||||||||||||
| middle Miocene | ||||||||||||
| 16 to 15 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Micropithecus leakeyorum | ||||||||||||
| Harrison , 1989 | ||||||||||||
Micropithecus leakeyorum is an extinct species of primates from the genus Micropithecus , whichoccurredin East Africa 16 to 15 million years ago - during the Middle Miocene . Micropithecus leakeyorum was first scientifically described in 1989. Micropithecus leakeyorum is after the type species of the genus Micropithecus , Micropithecus clarki , the second species placed in the genus.
Naming
Micropithecus is an artificial word . The name of the genus is derived from the Greek words μικρός ( ancient Greek spoken mikrós , "small") and πίθηκος (pronounced píthēkos , "monkey"). The epithet leakeyorum honors the British-Kenyan paleoanthropologist Louis Leakey (1903–1972) and his wife, the British paleoanthropologist Mary Leakey . Micropithecus leakeyorum thus means "Leakeys little monkey" and refers to the fact that the fossils of this genus are among the smallest fossil or recent species of human primates ever discovered .
Initial description
The holotype of Micropithecus leakeyorum is an approximately 16 to 15 million year old mandibular fragment with a preserved premolar P3 and the neighboring large molars M1 and M2 (archive number KNM-MB 11660; KNM = Kenya National Museum, MB = Maboko site). In addition, 22 other finds from the same site were added to the holotype as paratypes , mostly individually found teeth, but also several lower and upper jaw fragments and a large molar tooth from the Majiwa site, which is also located on Lake Victoria in Kenya.
According to the first description , Micropithecus leakeyorum has no morphological proximity to any other known species from the early or middle Miocene of East Africa than to the older Micropithecus clarki , which lived in the early Miocene 19 to 17 million years ago. This proximity results in particular from the very similar shape of the premolars and the large molars in both species of the genus. There is also a striking similarity with the species Dionysopithecus shuangouensis described in China in 1978 .
The morphology of the face resembles - as with Micropithecus clarki - most closely that of the gibbons living today , but the snout and the nasal region are relatively wide. The head-trunk length corresponds roughly to the white- forehead capuchin monkey, which is only around 35 centimeters tall, and is slightly smaller than that of the fossil Aeolopithecus chirobates (Simons, 1965).
Paleoecology
In the first description of Micropithecus leakeyorum it was discussed that in East Africa in the Miocene there was no other example besides Nyanzapithecus and Micropithecus for a genus of primates that existed for several million years and whose species could be documented in chronological order. However, from this sequence it cannot be concluded that the younger species emerged from the older one. The surviving remains of Micropithecus clarki show numerous original features of the Old World monkeys , but also various more recent features , such as relatively small molars in relation to the jawbone and very large incisors compared to the molars - features that all in all refer to a fruit-rich one Let diet close. Also Micropithecus leakeyorum has features that indicate a fruit diet, but these features are less pronounced than in the older sister-type. This was interpreted as a probable consequence of a lower specialization in a certain food, which gives this species a morphological similarity to the more original, much older Old World monkeys from East Africa.
One explanation for these different characteristics is obtained when the paleoecology noted that approximately 19 million years ago today were Uganda and western Kenya mostly covered by forests, encouraged by a warm and humid tropical - climate . Later the climate in this region changed, the forests became lighter and drier. These changes were probably caused by tectonic processes, which also had a local influence on the extent of the precipitation. For the excavation sites on Maboko Island, detailed studies of the flora have shown that in the Middle Miocene there were open, sparsely forested landscapes with dense gallery forests along the rivers, comparable to the vegetation of today's Nyika National Park . In such biotopes , it was concluded, the ancestors of Micropithecus leakeyorum gradually adjusted to a broader diet that also contained harder vegetable fibers.
literature
- Terry Harrison : A Taxonomic Revision of the Small Catarrhine Primates from the Early Miocene of East Africa. In: Folia Primatologica. Volume 50, No. 1-2, 1988, pp. 59-108. doi: 10.1159 / 000156334 .
Individual evidence
- ^ A b Terry Harrison : A new species of Micropithecus from the middle Miocene of Kenya. In: Journal of Human Evolution . Volume 18, No. 6, 1989, pp. 537-557, doi: 10.1016 / 0047-2484 (89) 90017-1
- ↑ John G. Fleagle , Elwyn L. Simons : Micropithecus clarki, a small ape from the Miocene of Uganda. In: American Journal of Physical Anthropology. Volume 49, No. 4, 1978, pp. 427-440. doi: 10.1002 / ajpa.1330490402
- ^ Elwyn L. Simons: New Fossil Apes from Egypt and the Initial Differentiation of Hominoidea. In: Nature . Volume 205, 1965, pp. 135-139. doi: 10.1038 / 205135a0
- ^ Terry Harrison, New finds of small fossil apes from the Miocene locality at Koru in Kenya. In: Journal of Human Evolution. Volume 10, No. 2, 1981, pp. 129-137. doi: 10.1016 / S0047-2484 (81) 80010-3