Gaviiformes

Source: Wikipedia, the free encyclopedia.

Gaviiformes
Temporal range: Early Eocene–Present
Common loon (Gavia immer)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Clade: Phaethoquornithes
Clade: Aequornithes
Order: Gaviiformes
Wetmore & Miller, 1926
Genera
Synonyms

Colymbiformes Sharpe, 1891

Gaviiformes (

aquatic birds containing the loons or divers and their closest extinct relatives. Modern gaviiformes are found in many parts of North America and northern Eurasia
(Europe, Asia and debatably Africa), though prehistoric species were more widespread.

Classification and evolution

There are five living species, and all are placed in the genus

plesiomorphic member of that order, was sometimes used to support claims of Albian (Early Cretaceous) Gaviiformes.[2][3]

More recently, it has become clear that the

anatomical features are easily misled into grouping loons and grebes.[2][4][5]

The

flamingos (Phoenicopteriformes). It is perhaps notable that some early penguins had skulls and beaks that were in many aspects similar to those of the known living and fossil Gaviiformes.[4][6]

Fossil record

Red-throated loon (G. stellata), the smallest living Gavia species. Some Miocene members of this genus were smaller still.

In prehistoric times, the loons had a more southerly distribution than today, and their fossils have been found in places such as California, Florida and Italy. The conflicting molecular data regarding their relationships is not much resolved by the fossil record; though they seem to have originated at the end of the Late Cretaceous like their presumed relatives, modern loons are only known with certainty since the Eocene. By that time almost all modern bird orders are at least strongly suspected to have existed – if not known from unequivocally identified specimens – anyway.[5]

The oldest known stem-gaviiform is Nasidytes from the Early Eocene aged London Clay of England, dating to around 55 million years ago.[7]

Cope's Rule.[9]

Some older fossils are sometimes assigned to the Gaviiformes. From the

Geiseltal (Germany) was erroneously assigned to Gavia.[11]

See also

References

  1. ^ Boertmann, D. (1990). "Phylogeny of the divers, family Gaviidae (Aves)". Steenstrupia. 16: 21–36.
  2. ^
    S2CID 11147804
    .
  3. ^ Brodkorb (1963: pp. 220–221)
  4. ^
  5. ^ a b Mayr (2009)
  6. ^ Olson (1985: pp. 212–213), Mayr (2004, 2009)
  7. ISSN 0024-4082
    .
  8. ^ Some (notably Robert W. Storer) have disagreed, usually because they separated Gaviella in the basalmost subfamily of the Gaviidae and considered Colymboides the ancestor of Gavia. More recent authors generally disagree at least regarding the latter: Storer (1956), Olson (1985), Mayr (2009: pp. 75–76)
  9. ^ Brodkorb (1953), 1963: pp. 223–225, Olson (1985: pp. 212–213), Mlíkovský (2002: pp. 63–64), Mayr (2009: pp. 75–76)
  10. ^ Not to be used without quotation marks, as it is not a valid taxon.
  11. ^ Brodkorb (1963: pp. 220–223), Olson (1985), Mlíkovský (2002: pp. 64, 259–261), Mayr (2009: p. 20)

Bibliography

Further reading

External links