Pan-Alcidae is a

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 ...

of charadriiform birds containing the

auk Auks or alcids are birds of the family Alcidae in the order Charadriiformes. The alcid family includes the Uria, murres, guillemots, Aethia, auklets, puffins, and Brachyramphus, murrelets. The family contains 25 extant or recently extinct speci ...

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 In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor ...

auks (Alcidae), but some have disputed the use of the Pan- prefix in general for family-group names regulated by the Zoocode (ICZN Code).Louchart, A., Viriot, L. & Dubois, A. (2013): The use of the prefix Pan- and other problems in zoological family-series nomenclature. Zootaxa 3750 (2): 197-200. doi: 10.11646/zootaxa.3750.2.9

Evolution and distribution

The earliest unequivocal

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s of pan-alcids are from the late

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 ...

, some 35 mya. The

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

'' Miocepphus'', (from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

, 15 mya) is the earliest known from associated specimens. Two Paleogene fossils were previously assigned to the Alcidae, but have since been removed to other clades: ''

Hydrotherikornis ''Hydrotherikornis oregonus'' is an extinct species of auk. The fossil specimen was found near Coos Bay Coos Bay (Hanis language, Coos language: Atsixiis or Hanisich) is an estuary where the Coos River enters the Pacific Ocean, the estuary is ...

'' (late

) is a procellariiform and ''

Petralca ''Petralca'' is an extinct genus of loon found in Oligocene and Miocene deposits of Austria. The type and only species, ''Petralca austriaca'', was described in 1987. It is the only member of the Petralcinae subfamily. Originally thought to be t ...

'' (Late

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

) is a loon. Most extant genera are known to exist since the Late Miocene or Early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its 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 (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

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.Konyukhov (2002) Possible ways of spreading and evolution in the alcids. Biology Bulletin 29:447-454. The flightless clade Mancallinae was present in the eastern and western Pacific Ocean and became extinct in the Late

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

References

{{Taxonbar, from=Q7129481 * Priabonian first appearances Extant Eocene first appearances