Miniopterus tao
Encyclopedia
Miniopterus tao is a fossil
bat in the genus Miniopterus
from the Pleistocene
of Zhoukoudian
in China. It is known from a number of mandible
s (lower jaws), which were initially identified as the living species Miniopterus schreibersii in 1963 before being recognized as a separate species, M. tao, in 1986. Miniopterus tao is larger than living M. schreibersii and has more closely spaced lower premolar
s and more robust talonids (back groups of cusps) on the lower molars
. The back part of the mandible is relatively low and on it, the coronoid
and condyloid process
es are about equally high. The average length of the mandible is 12.0 mm.
was the first to describe fossil bats from the fossil site of Zhoukoudian
Locality 1, which is famous for Peking Man
. However, he did not mention Miniopterus
, which was first recorded by Kazimierz Kowalski and Chuan-kuei Li in 1963 in a description of new material from layer 8 of the cave site. They identified the Miniopterus as the widespread living species Miniopterus schreibersii on the basis of 48 mandible
s (lower jaws) from layer 8 and reassigned another mandible that had previously been identified as Myotis to Miniopterus. In a 1986 paper, however, Bronisław Wołoszyn described the population as a new species, Miniopterus tao, after examining two mandibles in the collections of the Polish Academy of Sciences
. He did place the species in the "schreibersii group" of Miniopterus, but considered it unlikely to be ancestral to living M. schreibersii. The specific name, tao, refers to the Chinese philosophical concept, the Tao
.
(p3) through third molar
(m3), and the other intact and with the fourth premolar (p4) through second molar (m2). Miniopterus tao is a large member of the "schreibersii group" and about as large as Miniopterus rummeli from the Miocene
of Germany. The mandible is robust and generally resembles M. schreibersii. The mental foramen
(an opening at the outer side of the jaw) is located between the lower canine and second lower premolar (p2). The coronoid process
(a projection at the back of the mandible) is low and rounded and is connected to the condyloid process
behind it by a nearly horizontal ridge, which contains a slight raising at its back. Compared to M. schreibersii, the condyloid process is more slender, but the base of the angular process (at the lower back corner of the jaw) is more robust. In M. rummeli, the back part of the mandible is higher and the coronoid process is distinctly higher than the condyloid process.
The preserved alveoli
show that p2 is about as large as p3, not smaller as in the "tristis group" of Miniopterus. The premolars in M. tao are placed closely together, which distinguishes the species from M. schreibersii and fossil European species, including M. rummeli. The p3 is robust and surrounded by a well-developed cingulum (shelf). The crown is trapezoid
in shape. In p4, there is a clear cingulum at the front and labial (outer) margins. The crown is triangular and the back edge is straight, not saddle-shaped as in M. schreibersii. The molars resemble those of M. schreibersii, but are more robust, particularly the talonids (the cusp groups at the back of the teeth).
The total length of the mandible ranges from 11.6 to 12.4 mm and averages 12.0 mm in ten specimens, the coronoid process is 3.1 to 3.3 mm high, averaging 3.2 mm, and the length of the molar row is 4.0 to 4.4 mm, averaging 4.2 mm.
in age (between about 2 million and 10,000 years old) and also contains Ia io and species of Rhinolophus and Myotis among bats, in addition to Homo erectus
.
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
bat in the genus Miniopterus
Miniopterus
Miniopterus is a genus of bats and the only genus of the family Miniopteridae. The genus was previously placed in its own subfamily, Miniopterinae, of the vesper bat family, but is now classified in its own family....
from the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
of Zhoukoudian
Zhoukoudian
Zhoukoudian or Choukoutien is a cave system in Beijing, China. It has yielded many archaeological discoveries, including one of the first specimens of Homo erectus, dubbed Peking Man, and a fine assemblage of bones of the gigantic hyena Pachycrocuta brevirostris...
in China. It is known from a number of mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
s (lower jaws), which were initially identified as the living species Miniopterus schreibersii in 1963 before being recognized as a separate species, M. tao, in 1986. Miniopterus tao is larger than living M. schreibersii and has more closely spaced lower premolar
Premolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...
s and more robust talonids (back groups of cusps) on the lower molars
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
. The back part of the mandible is relatively low and on it, the coronoid
Coronoid process of the mandible
The mandible's coronoid process is a thin, triangular eminence, which is flattened from side to side and varies in shape and size....
and condyloid process
Condyloid process
The condyloid process is part of the mandible and is thicker than the coronoid, and consists of two portions: the condyle, and the constricted portion which supports it, the neck.-Condyle :...
es are about equally high. The average length of the mandible is 12.0 mm.
Taxonomy
In 1934, Chinese paleontologist C.C. YoungYang Zhongjian
Yang Zhongjian , courtesy name Keqiang , also known as C.C. Young, was one of China's foremost paleontologists. He has been called the 'Father of Chinese vertebrate paleontology'...
was the first to describe fossil bats from the fossil site of Zhoukoudian
Zhoukoudian
Zhoukoudian or Choukoutien is a cave system in Beijing, China. It has yielded many archaeological discoveries, including one of the first specimens of Homo erectus, dubbed Peking Man, and a fine assemblage of bones of the gigantic hyena Pachycrocuta brevirostris...
Locality 1, which is famous for Peking Man
Peking Man
Peking Man , Homo erectus pekinensis, is an example of Homo erectus. A group of fossil specimens was discovered in 1923-27 during excavations at Zhoukoudian near Beijing , China...
. However, he did not mention Miniopterus
Miniopterus
Miniopterus is a genus of bats and the only genus of the family Miniopteridae. The genus was previously placed in its own subfamily, Miniopterinae, of the vesper bat family, but is now classified in its own family....
, which was first recorded by Kazimierz Kowalski and Chuan-kuei Li in 1963 in a description of new material from layer 8 of the cave site. They identified the Miniopterus as the widespread living species Miniopterus schreibersii on the basis of 48 mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
s (lower jaws) from layer 8 and reassigned another mandible that had previously been identified as Myotis to Miniopterus. In a 1986 paper, however, Bronisław Wołoszyn described the population as a new species, Miniopterus tao, after examining two mandibles in the collections of the Polish Academy of Sciences
Polish Academy of Sciences
The Polish Academy of Sciences, headquartered in Warsaw, is one of two Polish institutions having the nature of an academy of sciences.-History:...
. He did place the species in the "schreibersii group" of Miniopterus, but considered it unlikely to be ancestral to living M. schreibersii. The specific name, tao, refers to the Chinese philosophical concept, the Tao
Tao
Dao or Tao is a Chinese word meaning 'way', 'path', 'route', or sometimes more loosely, 'doctrine' or 'principle'...
.
Description
Wołoszyn described the species on the basis of two mandibles, one damaged and with the third premolarPremolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...
(p3) through third molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
(m3), and the other intact and with the fourth premolar (p4) through second molar (m2). Miniopterus tao is a large member of the "schreibersii group" and about as large as Miniopterus rummeli from the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
of Germany. The mandible is robust and generally resembles M. schreibersii. The mental foramen
Mental foramen
The mental foramen is one of two holes located on the anterior surface of the mandible. It permits passage of the mental nerve and vessels. The mental foramen descends slightly in edentulous individuals.- Variations :...
(an opening at the outer side of the jaw) is located between the lower canine and second lower premolar (p2). The coronoid process
Coronoid process of the mandible
The mandible's coronoid process is a thin, triangular eminence, which is flattened from side to side and varies in shape and size....
(a projection at the back of the mandible) is low and rounded and is connected to the condyloid process
Condyloid process
The condyloid process is part of the mandible and is thicker than the coronoid, and consists of two portions: the condyle, and the constricted portion which supports it, the neck.-Condyle :...
behind it by a nearly horizontal ridge, which contains a slight raising at its back. Compared to M. schreibersii, the condyloid process is more slender, but the base of the angular process (at the lower back corner of the jaw) is more robust. In M. rummeli, the back part of the mandible is higher and the coronoid process is distinctly higher than the condyloid process.
The preserved alveoli
Dental alveolus
Dental alveolus are sockets in the jaws in which the roots of teeth are held in the alveolar process of maxilla with the periodontal ligament. The lay term for dental alveoli is tooth sockets...
show that p2 is about as large as p3, not smaller as in the "tristis group" of Miniopterus. The premolars in M. tao are placed closely together, which distinguishes the species from M. schreibersii and fossil European species, including M. rummeli. The p3 is robust and surrounded by a well-developed cingulum (shelf). The crown is trapezoid
Trapezoid
In Euclidean geometry, a convex quadrilateral with one pair of parallel sides is referred to as a trapezoid in American English and as a trapezium in English outside North America. A trapezoid with vertices ABCD is denoted...
in shape. In p4, there is a clear cingulum at the front and labial (outer) margins. The crown is triangular and the back edge is straight, not saddle-shaped as in M. schreibersii. The molars resemble those of M. schreibersii, but are more robust, particularly the talonids (the cusp groups at the back of the teeth).
The total length of the mandible ranges from 11.6 to 12.4 mm and averages 12.0 mm in ten specimens, the coronoid process is 3.1 to 3.3 mm high, averaging 3.2 mm, and the length of the molar row is 4.0 to 4.4 mm, averaging 4.2 mm.
Range
Miniopterus tao has only been recorded from Locality 1 at Zhoukoudian; Locality 3 contains a smaller Miniopterus identified as M. schreibersii. Locality 1 is PleistocenePleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
in age (between about 2 million and 10,000 years old) and also contains Ia io and species of Rhinolophus and Myotis among bats, in addition to Homo erectus
Homo erectus
Homo erectus is an extinct species of hominid that lived from the end of the Pliocene epoch to the later Pleistocene, about . The species originated in Africa and spread as far as India, China and Java. There is still disagreement on the subject of the classification, ancestry, and progeny of H...
.
Literature cited
- Kowalski, K. and Li, C.-K. 1963. Remarks on the fauna of bats (Chiroptera) from locality 1 at Choukoutien. Vertebrata PalAsiatica 7(2):144–150.
- Wołoszyn, B.W. 1986. A new species of long-winged bat Miniopterus tao sp. n. (Mammalia: Chiroptera) from locality 1 at Choukoutien, China. Acta Universitatis Carolinae, Geologica 1986(2):205–211.
- Ziegler, R. 2003. Bats (Chiroptera, Mammalia) from Middle Miocene karstic fissure fillings of Petersbuch near Eichstätt, Southern Franconian Alb (Bavaria) (subscription required). Geobios 36(4):447–490.