''Icaronycteris'' is an extinct genus of
microchiropteran (echolocating)
bat
Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most bi ...
that lived in the early
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
, approximately , making it the earliest known definitive bat.
Four exceptionally preserved specimens, among the best preserved bat fossils, are known from the
Green River Formation
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine ...
of North America.
There is only one thoroughly described species of bat in the genus, ''I. index'',
although fragmentary material from France has also been tentatively placed within ''Icaronycteris'' as the second species ''I. menui''.
''I. sigei'' is based on well-preserved fragments of dentaries and lower teeth found in
Western India
Western India is a loosely defined region of India consisting of its western part. The Ministry of Home Affairs in its Western Zonal Council Administrative division includes the states of Goa, Gujarat, and Maharashtra along with the Union te ...
.
Description
''Icaronycteris'' measured about long and had a wingspan of . It closely resembled modern bats, but had some primitive traits. The tail was much longer and not connected to the hind legs with a skin membrane, the first wing finger bore a claw and the body was more flexible. Similarly, it had a full set of relatively unspecialised teeth, similar to those of a modern
shrew
Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to different fa ...
. Its anatomy suggests that, like modern bats, ''Icaronycteris'' slept while hanging upside down, holding onto a tree branch or stone ridge with its hind legs.
Phylogeny
According to ,
''Icaronycteris'' is the first genus, followed by ''
Archaeonycteris'', ''
Hassianycetris'', and ''
Palaeochiropteryx
''Palaeochiropteryx'' ( ) is an extinct genus of bat from the Middle Eocene of Europe and North America. It contains three very similar species – ''Palaeochiropteryx tupaiodon'' and ''Palaeochiropteryx spiegeli'', both from the famous Messel ...
'', in a series leading to extant microchiropteran bats.
See also
* ''
Onychonycteris
''Onychonycteris'' is the more primitive of the two oldest known monospecific genera of bat, having lived in the area that is current day Wyoming during the Eocene period, 52.5 million years ago.
Taxonomy
Two specimens of ''Onychonycteris'' we ...
''
* ''
Australonycteris''
References
Notes
Sources
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Further reading
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{{Taxonbar, from=Q1062126
Prehistoric bat genera
Eocene bats
Fossil taxa described in 1966
Eocene mammals of North America