Eostrix
Encyclopedia
Eostrix is an extinct genus of the family Protostrigidae from early Eocene
of Wyoming
and the London Clay
of England. It was erected by Pierce Brodkorb in 1971 to place a fossil species known until that time as Protostrix mimica.
Two species are recognised. E. martinellii was described in 1972 from a left tarsometatarsus
(lower leg bone) recovered from an escarpment above the southeastern bank of Cottonwood Creek in Fremont County, Wyoming by Jorge Martinelli on a field trip in 1970 under the auspices of the University of Kansas. The strata was a Lysite member of the Wind River Formation. Martinelli was studying paleontology at the University of Barcelona. Paleontologists Larry D. Martin and Craig C. Black from the Museum of Natural History named it in his honour. The smaller of the two species, it was similar in size to the living Long-eared Owl
(Asio otus). Differences in the trochlea
s (grooves) of the lower end of the tarsometatarsus set it apart from living owls, namely a groove in the trochlea for digit 2, a deeper posterior groove in a relatevely narrow trochlea for digit 3, and an unusually rounded trochlea for digit 4.
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
of Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
and the London Clay
London Clay
The London Clay Formation is a marine geological formation of Ypresian age which crops out in the southeast of England. The London Clay is well known for the fossils it contains. The fossils from the Lower Eocene indicate a moderately warm climate, the flora being tropical or subtropical...
of England. It was erected by Pierce Brodkorb in 1971 to place a fossil species known until that time as Protostrix mimica.
Two species are recognised. E. martinellii was described in 1972 from a left tarsometatarsus
Tarsometatarsus
The tarsometatarsus is a bone that is found in the lower leg of certain tetrapods, namely birds.It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsal and metatarsal bones...
(lower leg bone) recovered from an escarpment above the southeastern bank of Cottonwood Creek in Fremont County, Wyoming by Jorge Martinelli on a field trip in 1970 under the auspices of the University of Kansas. The strata was a Lysite member of the Wind River Formation. Martinelli was studying paleontology at the University of Barcelona. Paleontologists Larry D. Martin and Craig C. Black from the Museum of Natural History named it in his honour. The smaller of the two species, it was similar in size to the living Long-eared Owl
Long-eared Owl
The Long-eared Owl - Asio otus is a species of owl which breeds in Europe, Asia, and North America. This species is a part of the larger grouping of owls known as typical owls, family Strigidae, which contains most species of owl...
(Asio otus). Differences in the trochlea
Trochlea
Trochlea is a term in anatomy. It refers to a grooved structure reminiscent of a pulley's wheel.Most commonly, trochleae bear the articular surface of saddle and other joints:* Trochlea of humerus* Trochlear process of the Calcaneus...
s (grooves) of the lower end of the tarsometatarsus set it apart from living owls, namely a groove in the trochlea for digit 2, a deeper posterior groove in a relatevely narrow trochlea for digit 3, and an unusually rounded trochlea for digit 4.