Aegialornis
Encyclopedia
Aegialornis
is a genus
of prehistoric apodiform
bird
. It formed a distinct family
Aegialornithidae and was in some ways intermediate between modern swift
s and owlet-nightjar
s, lacking the more extreme adaptations to an aerial lifestyle that swifts show today, but already having sickle-shaped wings like them. They do not appear to be a direct ancestor of modern swifts, however, but rather a group that retained an overall basal morphology. Altogether, they were not too dissimilar to modern treeswift
s.
Fossils of Aegialornis have been found in Middle to Late Eocene
deposits of Germany
and France
. An Early Eocene record from the Nanjemoy Formation of Virginia
, USA (USNM 496384) is very doubtful, as apodiform birds seem not to have occurred there until after the Eocene. This bone might more properly belong to the Parvicuculidae (Mayr & Mourer-Chauviré 2005). The taxonomy of the species is quite convoluted, with both the smaller A. germanicus and the larger A. leenhardti being sometimes considered junior synonyms of A. gallicus, which in turn is sometimes erroneously assumed to be identical to Cypselavus gallicus. Similarly, A. broweri is occasionally considered to be based on small individuals of A. wetmorei, and these latter two taxa were recently separated as genus Mesogiornis (Mlíkovský, 2002); this does not appear to have found general acceptance however. The presumed species Aegialornis szarskii is now placed in Scaniacypselus.
It is not quite certain which genera apart from the present one should be included in the Aegialornithidae. Primapus
belongs either here or is a basal true swift, and Cypselavus is either an aegialornithid or a treeswift. The latter group is sometimes controversially included in the Aegialornithidae, as are the Jungornithidae, another prehistoric apodiform family that was somewhat intermediate between treeswifts and hummingbirds.
is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of prehistoric apodiform
Apodiformes
Traditionally, the bird order Apodiformes contained three living families: the swifts , the tree swifts , and the hummingbirds . In the Sibley-Ahlquist taxonomy, this order is raised to a superorder Apodimorphae in which hummingbirds are separated as a new order, Trochiliformes...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
. It formed a distinct family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Aegialornithidae and was in some ways intermediate between modern swift
Swift
The swifts are a family, Apodidae, of highly aerial birds. They are superficially similar to swallows, but are actually not closely related to passerine species at all; swifts are in the separate order Apodiformes, which they share with hummingbirds...
s and owlet-nightjar
Owlet-nightjar
Owlet-nightjars are small nocturnal birds related to the nightjars and frogmouths. Most are native to New Guinea, but some species extend to Australia, the Moluccas, and New Caledonia. A New Zealand species is extinct...
s, lacking the more extreme adaptations to an aerial lifestyle that swifts show today, but already having sickle-shaped wings like them. They do not appear to be a direct ancestor of modern swifts, however, but rather a group that retained an overall basal morphology. Altogether, they were not too dissimilar to modern treeswift
Treeswift
The treeswifts or crested swifts are a family, Hemiprocnidae, of aerial near passerine birds, closely related to the true swifts. The family contains a single genus, Hemiprocne, with four species...
s.
Fossils of Aegialornis have been found in Middle to Late Eocene
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...
deposits of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
and France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
. An Early Eocene record from the Nanjemoy Formation of Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
, USA (USNM 496384) is very doubtful, as apodiform birds seem not to have occurred there until after the Eocene. This bone might more properly belong to the Parvicuculidae (Mayr & Mourer-Chauviré 2005). The taxonomy of the species is quite convoluted, with both the smaller A. germanicus and the larger A. leenhardti being sometimes considered junior synonyms of A. gallicus, which in turn is sometimes erroneously assumed to be identical to Cypselavus gallicus. Similarly, A. broweri is occasionally considered to be based on small individuals of A. wetmorei, and these latter two taxa were recently separated as genus Mesogiornis (Mlíkovský, 2002); this does not appear to have found general acceptance however. The presumed species Aegialornis szarskii is now placed in Scaniacypselus.
It is not quite certain which genera apart from the present one should be included in the Aegialornithidae. Primapus
Primapus
Primapus is an extinct genus of apodiform bird from the Early Eocene of the United Kingdom. Its fossils were found in the London Clay, which was deposited around 50 million years ago. The type species is P. lacki.-Sources:...
belongs either here or is a basal true swift, and Cypselavus is either an aegialornithid or a treeswift. The latter group is sometimes controversially included in the Aegialornithidae, as are the Jungornithidae, another prehistoric apodiform family that was somewhat intermediate between treeswifts and hummingbirds.
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