Pan-Alcidae
Encyclopedia
Pan-Alcidae is a clade
of charadriiform
birds containing the auk
s and their extinct relatives. It was named in 2011 by N.A. Smith, who defined it as all descendants of the common ancestor of the group Mancallinae
and crown group
auks (Alcidae).
The earliest unequivocal fossil
s of pan-alcids are from the late Eocene
, some 35 mya. The genus
Miocepphus, (from the Miocene
, 15 mya) is the earliest known from good specimens. Two very fragmentary fossils are often assigned to the Alcidae, although this may not be correct: Hydrotherikornis (late Eocene
) and Petralca (Late Oligocene
). Most extant genera are known to exist since the Late Miocene or Early Pliocene
(c. 5 mya). Miocene fossils have been found in both California
and Maryland
, but the greater diversity of fossils and tribes in the Pacific leads most scientists to conclude that it was there they first evolved, and it is in the Miocene Pacific that the first fossils of extant genera
are found. Early movement between the Pacific and the Atlantic probably happened to the south (since there was no northern opening to the Atlantic), later movements across the Arctic Ocean. The flightless subfamily Mancallinae
which was apparently restricted to the Pacific coast of southern North America became extinct in the Early Pleistocene
.
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of charadriiform
Charadriiformes
Charadriiformes is a diverse order of small to medium-large birds. It includes about 350 species and has members in all parts of the world. Most Charadriiformes live near water and eat invertebrates or other small animals; however, some are pelagic , some occupy deserts and a few are found in thick...
birds containing the auk
Auk
An auk is a bird of the family Alcidae in the order Charadriiformes. Auks are superficially similar to penguins due to their black-and-white colours, their upright posture and some of their habits...
s and their extinct relatives. It was named in 2011 by N.A. Smith, who defined it as all descendants of the common ancestor of the group Mancallinae
Mancallinae
The Mancallinae were a sub-family of prehistoric flightless auk relatives that lived on the Pacific coast of today's California and Mexico from the late Miocene epoch to the early Pleistocene...
and crown group
Crown group
A crown group is a group consisting of living representatives, their ancestors back to the most recent common ancestor of that group, and all of that ancestor's descendants. The name was given by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms...
auks (Alcidae).
Evolution and distribution
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s of pan-alcids are from the 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...
, some 35 mya. The 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...
Miocepphus, (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...
, 15 mya) is the earliest known from good specimens. Two very fragmentary fossils are often assigned to the Alcidae, although this may not be correct: Hydrotherikornis (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...
) and Petralca (Late Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
). Most extant genera are known to exist since the Late Miocene or Early Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
(c. 5 mya). Miocene fossils have been found in both California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
, but the greater diversity of fossils and tribes in the Pacific leads most scientists to conclude that it was there they first evolved, and it is in the Miocene Pacific that the first fossils of extant genera
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...
are found. Early movement between the Pacific and the Atlantic probably happened to the south (since there was no northern opening to the Atlantic), later movements across the Arctic Ocean. The flightless subfamily Mancallinae
Mancallinae
The Mancallinae were a sub-family of prehistoric flightless auk relatives that lived on the Pacific coast of today's California and Mexico from the late Miocene epoch to the early Pleistocene...
which was apparently restricted to the Pacific coast of southern North America became extinct in the Early 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 ....
.
Classification
- Pan-Alcidae
- Hydrotherikornis? (Late Eocene of Oregon, USA)
- Pseudocepphus? (Middle - Late Miocene) – basal Alcinae?
- Subfamily Petralcinae?
- Petralca (Early ?- Late Oligocene of Austria)
- Subfamily MancallinaeMancallinaeThe Mancallinae were a sub-family of prehistoric flightless auk relatives that lived on the Pacific coast of today's California and Mexico from the late Miocene epoch to the early Pleistocene...
- Family Alcidae