Morsoravidae is a family of

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

birds known from the

Early Eocene In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, related to the Psittacopasseres, the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

containing

parrot Parrots (Psittaciformes), also known as psittacines (), are birds with a strong curved beak, upright stance, and clawed feet. They are classified in four families that contain roughly 410 species in 101 genus (biology), genera, found mostly in ...

s and

songbird A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes contains 5,00 ...

s. They have specialised feeding ecologies, and one morsoravid, '' Pumiliornis tesselatus'', fed on nectar. The family contains the genera '' Morsoravis'', '' Pumiliornis'', and ''

Sororavis ''Sororavis'' is an extinct genus of bird from the Early Eocene London Clay of Walton-on-the-Naze, United Kingdom. It contains a single named species, ''Sororavis solitarius''. It is a member of the Morsoravidae. Discovery and naming The holoty ...

''.

Description

Common to the Morsoravidae is a distinctive morphology of the

tarsometatarsus The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bird bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) a ...

. The trochlea of the second and fourth metatarsals are distinct, and the fourth metatarsal trochlea is slanted in a way that strongly suggests that morsoravids were at least facultatively

zygodactyl In biology, dactyly is the arrangement of digits (fingers and toes) on the hands, feet, or sometimes wings of a tetrapod animal. The term is derived from the Greek word () meaning "finger." Sometimes the suffix "-dactylia" is used. The derive ...

. The second metatarsal trochlea is characterised by large size (compared to Psittacopedidae and

Zygodactylidae Zygodactylidae is a family of extinct birds found in Europe and North America from the Eocene epoch to the Middle Miocene. First named in 1971, based on fragmentary remains of two species from Germany, a more complete description of the birds bec ...

) and a cylindrical shape that allows little rotational movement of the toe. These adaptations are thought to improve these birds' climbing ability. One morsoravid, a 47-million year old specimen of ''Pumiliornis tesselatus'', has been found with pollen grains in its gut, indicating at least some level of

nectarivory In zoology, a nectarivore is an animal which derives its energy and nutrient requirements from a diet consisting mainly or exclusively of the sugar-rich nectar produced by flowering plants. Nectar as a food source presents a number of benefits ...

. Another morsoravid, ''Sororavis solitarius'', is similar to

mousebird The mousebirds are birds in the order Coliiformes. They are the sister group to the clade Cavitaves, which includes the Leptosomiformes (the cuckoo roller), Trogoniformes ( trogons), Bucerotiformes ( hornbills and hoopoes), Piciformes ( wo ...

s in details of the legs, suggesting that it could have been able to hang off of branches to reach food items.

Distribution

Although the named species of Morsoravidae are all known from European sites only, there is evidence that they also lived in North America in the early

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

. A skeleton found 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 (Colorado River), Green River in Colorado, Wyoming, and Utah. The sedimen ...

in the United States is closely related to ''Morsoravis'' and ''Sororavis''. Other morsoravids are known from the

Fur Formation The Fur Formation is a marine geological formation of Ypresian ( Lower Eocene Epoch, c. 56.0-54.5 Ma) age which crops out in the Limfjord region of northern Denmark from Silstrup via Mors and Fur to Ertebølle, and can be seen in many cliffs and ...

of Denmark, the

Messel Pit The Messel Formation is a Formation (geology), geologic formation in Hesse, central Germany, dating back to the Eocene Epoch (geology), epoch (about 47 Ma). Its geographic range is restricted to the Messel pit. There it unconformably overlie ...

in Germany, and the

London Clay The London Clay Formation is a Sediment#Shores and shallow seas, marine formation (geology), geological formation of Ypresian (early Eocene Epoch, c. 54-50 million years ago) age which outcrop, crops out in the southeast of England. The London C ...

of England.

References

{{Taxonbar, from=Q123463367 Eocene birds Prehistoric bird families Neognathae

Description

Distribution

See also

References