Paleognathae

Taxobox
name = Paleognaths
fossil_range = Paleocene - Recent


image_width = 250px
image_caption = A kiwi
regnum = Animalia
phylum = Chordata
classis = Aves
subclassis = Carinatae
infraclassis = Neornithes
superordo = Paleognathae
superordo_authority = Pycraft, 1900
synonyms = Palaeognathia Huxley, 1867
subdivision_ranks = Orders
subdivision ="Primary classification"
*Lithornithiformes
*Dinornithiformes
*Aepyornithiformes
*Struthioniformes
*Rheiformes
*Casuariiformes
*Apterygiformes
*Tinamiformes"Alternate classification"
*Lithornithiformes
*Struthioniformes
*Tinamiformes
"see text for more info"
vernacular names =
*en=Paleognaths, old jaws
*fi=Vanhaleukaiset
*ja=古顎下綱
*pl=Paleognatyczne
*zh=古颚总目
*ru=Бескилевые
*de=Urkiefervögel
*uk=Безкілеві

The Paleognathae or paleognaths ("old jaws") are one of the two living superorders of birds. The other living superorder is Neognathae.

The paleognaths contain several living orders of birds, the Tinamiformes (tinamous), the Apterygiformes (kiwis), Casuariiformes (cassowaries and emus), Rheiformes (rheas), and the Struthioniformes (ostriches). All but the tinamous are flightless. There are also many extinct orders: the Lithornithiformes, the Ambiornithiformes, the Gansuiformes, the Paleocursornithiformes, the Dinornithiformes (moas), and the Aepyornithiformes (elephant birds).

Most paleognaths have long necks and long legs, and are specialized for running rather than flight; indeed, the ratites are all completely flightless. The group is not separated because of this though, it is rather based on the form of the jaw. Paleognaths other than tinamous are commonly known as ratites from the Latin word for raft, "ratis", because they have a breastbone shaped like a raft.

Anatomy and characteristics

Ratite birds are the easiest birds to distinguish - they are mostly large, flightless, have extended necks, a breastbone shaped like a raft (with the exception of tinamous), they have a simpified wing bone structure, strong legs, and no feather vanes, making it unnecessary to oil their feathers. And as a direct result of this they have no preen gland that contains preening oil.

Ratite sizes range from 10 inches (25 centimeters) to 9 feet (2.7 meters) and weight can be from 2.86 pounds (1.3 kilograms) to 345 pounds (155.25 kilograms). Ostriches are the largest struthioniforms (members of the Struthioniformes order), with long legs and neck. They range in height from 5.7 to 9 feet (1.8 to 2.7 meters) and weigh from 139 to 345 pounds (63 to 157 kilograms). They have loose-feathered wings. Males have black and white feathers while the female has grayish brown feathers. Emus are about 6.5 feet in height and weigh 51 to 120 pounds (23 to 55 kilograms). They have long, strong legs and can run up to 30 miles per hour (48 kilometers per hour). They have short wings and the adults have brown feathers. Rheas are 4.5 to 5.6 feet (1.3 to 1.7 meters) and weigh 55 to 88 pounds (24.75 to 40 kilograms). Their feathers are gray or spotted brown and white. Cassowaries are 3.3 to 5.6 feet (1 to 1.7 meters) in height and weigh 30 to 130 pounds (14 to 59 kilograms). They have tiny wings with black feathers. Kiwis are the smallest of ratites, ranging in height from 14 to 22 inches (35 to 55 centimeters) and weight 2.6 to 8.6 pounds (1.2 to 3.9 kilograms). They have brown and black hair-like feathers. The tinamous have a keeled breastbone (shaped like a wishbone) and can fly. They range in size from 8 to 21 inches (20 to 53 centimeters) and weigh 1.4 ounces to 5 pounds (43 grams to 2.3 kilograms). The basic anatomy of ratites is simple in principle and there are few exceptions to the rules stated.

Evolution

Paleognaths probably descended from a common ancestor in the late Cretaceous period on the supercontinent of Gondwana.Fact|date=September 2008 As the continents separated several forms of paleognaths reached different parts of the world, to support this idea all the continents where living (ostrich, cassowary, kiwi, tinamous, emu, and the rhea) and various fossil forms are found were connected during the late Cretaceous.Fact|date=September 2008 Recent genetic evidence seems to also point towards this theory, DNA shows that they may not be descended from one common ancestor, but two or more.Fact|date=September 2008 The results also show that ratites probably didn't lose the ability to fly until the middle Eocene.Fact|date=September 2008 Many similarites in morphology and genetic analysis show that there is probably no convergent evolution between ratite birds.Fact|date=September 2008 Currently, there is no exact way to say where, why, or when the paleognaths diverged.Fact|date=September 2008

Systematics and taxonomy

As told in the Evolution section of this article, the exact evolutionary history of the paleognaths is unresolved presently. Despite this many taxonomists try to place them in the grand scheme of the Aves. As a result two main branches developed, they are shown in the classification part below.

Early taxonomy

Initially the ratites were placed in a single group Ratita. Later it was realized that they were too different to be placed in a single order, so they were split into the several orders in the infobox at the top of this article. Then they were split into two orders, the Struthioniformes and the Lithioniformes. Although the first classification is adopted in this article, either one is commonly used in sources.

Classification

* Order Lithornithiformes (fossil)
** Family Lithornithidae
*** Genus "Lithornis" (Paleocene - Early Eocene)
*** Genus "Promusophaga" (Early Eocene)
*** Genus "Paracathartes" (Early Eocene of WC USA) - tentatively placed here
*** Genus "Pseudocrypturus" - tentatively placed here
* Order Dinornithiformes - moa (prehistoric/extinct)
** Family Dinornithidae
*** Genus "Dinornis" - giant moa (2-4 species)
** Family Anomalopterygidae - lesser moas
*** Subfamily Emeinae
**** Genus "Emeus" - Eastern Moa
**** Genus "Euryapteryx" - broad-billed or turkey moas (2 species)
**** Genus "Zelornis"
*** Subfamily Anomalopteryginae
**** Genus "Anomalopteryx" - Bush Moas
**** Genus "Megalapteryx" - upland moas (2 species)
**** Genus "Pachyornis" - stout moas (3-5 species)
* Order Aepyornithiformes - elephant birds (prehistoric/extinct)
** Family Aepyornithidae
*** Genus "Aepyornis" (4 species)
*** Genus "Mullerornis" (4 species)
* Order Struthioniformes - ostriches
** Family Struthionidae
*** Genus "Palaeotis" (fossil: Middle Eocene) - includes "Palaeogrus geiseltalensis"
**** "Palaeotis wiegelti"
*** Genus "Struthio" (1 living species)
* Order Rheiformes
** Family Opistodactylidae (fossil)
*** Genus "Opisthodactylus" (Miocene of Argentina) - rheid?
*** Genus "Diogenornis" - tentatively placed here
** Family Rheidae - rheas
*** Genus "Heterorhea" (fossil: Pliocene of Argentina)
*** Genus "Hinasuri" (fossil)
*** Genus "Rhea" (2 species, includes "Pterocnemia")
**** "Rhea americana" - common rhea
**** "Rhea pennata" - Darwin's rhea
* Order Casuariiformes
** Family Casuariidae - cassowaries
*** Genus "Casuarius"
** Family Dromaiidae
*** Genus "Emuarius" - "emuwaries" (fossil: Late Oligocene - Late Miocene; formerly in "Dromaius")
*** Genus "Dromaius" - emus (1 living species, 2 recently extinct)
* Order Apterygiformes - kiwis
** Family Apterygidae
*** Genus "Apteryx" (about 6 living species, possibly 1 recently extinct)
* Order Tinamiformes - tinamous
** Family Tinamidae
*** Subfamily Tinaminae
**** Genus "Crypturellus"
**** Genus "Tinamus"
**** Genus "Nothocercus"
**** Genus "Taoniscus"
**** Genus "Tinamotis"
*** Subfamily Rhynchotinae
**** Genus "Eudromia" - crested tinamous
**** Genus "Rhynchotus"
**** Genus "Nothoprocta"
**** Genus "Nothura" - nothuras

Alternate classification

*Superorder Paleognathae
**Order Struthioniformes
**Order Lithioniformes
**Order Tinamiformes

ometimes placed here

* "Ambiortus"
* "Eremopezus" - includes "Stromeria"
* "Gansus"
* "Limenavis"
* "Palaeocursornis"
* "Wyleyia"

"Paraphysornis" is a phorusrhacid.

Ootaxa
* "Gobioolithus" (Late Cretaceous) - paleognath?
* "Incognitoolithus" (Eocene of North America) - ratite?
* Type A ("aepyornithoid") eggs (Tsondab Early Miocene of Namibia - Pliocene of Asia)
* "Namornis" (Middle Miocene of Namibia - Late Miocene of Kenya) - ratite?
* "Diamantornis" (Middle Miocene of Namibia - Late Miocene of UAE and Kenya) - ratite?
* "Psammornis" - may be from "Eremopezus"

Locomotion

Many of the larger ratite birds have extremely long legs and the largest living bird, the ostrich, can run at speeds over 60 km/h. Cassowaries, emus, and rheas show a similar likeness in agility and some extinct forms may have reached speeds of 75 km/h. Moas, the largest birds, had legs over 3 feet high and may have been the fastest land animals to live outrunning even the cheetah.

Paleognaths and humans

Paleognaths probably first interacted with Australopithecines about 3 million or so years ago in the middle Pliocene in the form of an ancient ostrich or elephant bird. As "Homo erectus" evolved and left Africa for other continents not much contact was made with ratites, until the Maori and Aborigines arrived in New Zealand and Australia. Like many other native species, they were not well-adapted to environments containing humans, and many ratites (and other Oceanic species) became extinct during this period. Worldwide, most giant birds became extinct by the end of the 18th centurys and most surviving species are now endangered.

Today, ratites such as the Ostrich are farmed and sometimes even kept as pets. Ratites play a large part of human culture- they are farmed, eaten, raced, protected, and kept in zoos.

See also

* Fossil birds
* Late Quaternary prehistoric birds
* Extinct birds
* Flightless birds

References

cite book
last=Harrison
first=C.J.O.
author link = Dr. C.J.O. Harrison
last=Perrins
first=Christopher
author link = Dr. Christopher Perrins
title=Birds: their life, their ways, their world
publisher=The Reader's Digest Association, Inc.
date=1979
location=Pleasantville, New York
pages=8-412
isbn=0-89577-065-2

cite book
last=Lambert
first=David
author link = David Lambert
last=Naish
first=Darren
author link = Darren Naish
last=Wyse
first=Elizabeth
author link = Elizabeth Wyse
title=Dinosaur Encyclopedia: from dinosaurs to the dawn of man
publisher=DK publishing, inc.
date=2001
location=New York, New York
pages=138-145
isbn=0-7894-7935-4

cite book
author link = Smithsonian Institution
title=Animal: the definitive visual guide to the world's wildlife
publisher=DK publishing, inc.
date=2005
location=New York, New York
pages=260-265
isbn=0-7894-7764-5

cite book
last=Monroe
first=Burt
author link = Burt L. Monroe
last=Charles
first=Sibley
author link = Charles Gald Sibley
title=A World Checklist of Birds
publisher=Yale University Press
date=1993
location=New Haven
isbn=0-3000-5547-1

cite book
last=Elwood
first=Ann
author link = Ann Elwood
title=Ostriches, emus, rheas, kiwis, & cassowaries
publisher=Creative Education
date=1991
location=Mankato, Minnesota
isbn=0-8868-2338-2

cite book
last=Wexo
first=John
author link = John Bonnett Wexo
title=Zoobooks: Ostriches and other Ratites
publisher=Wildlife Education
date=2000
location=Poway, California
isbn=1-8881-5357-1

cite book
title=The Ratite Encyclopedia
publisher=Charley Elrod
date=1996
isbn=0-0642-9402-8

External links

* [http://animaldiversity.ummz.umich.edu/site/accounts/classification/Paleognathae.html#Paleognathae| Page On the classification of Paleognaths of Animal Diversity Web]
* [http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Archosauria/Aves/Palaeognathia/paleognathia.htm| Regional Cladogram of Paleognaths]
* [http://www.palaeos.com/Vertebrates/Units/350Aves/350.900.html| Evolutionary Cladogram of Paleognaths]
* [http://www.damisela.com/zoo/ave/ratities/index.htm| Spanish Page on Ratites]
* [http://www.fsis.usda.gov/Fact_Sheets/Ratites_Emu_Ostrich_Rhea/index.asp| Info on How to Prepare Ratites as Food]
* [http://www.bsc-eoc.org/avibase/avibase.jsp?pg=home&lang=EN&id=undefined&ts=undefined| Avibase]
* [http://www.ucmp.berkeley.edu/diapsids/birds/palaeognathae.html| Introduction to the Paleognathae]
* [http://mbe.oxfordjournals.org/cgi/content/full/21/6/974| Oxford Journal on the Molecular Biology and Evolution of Aves]
* [http://dml.cmnh.org/2004Feb/msg00017.html| Paleognath Monophyly]
* [http://yalepress.yale.edu/yupbooks/OnlineCatalog.asp?catalog=888607| Ornithology and Natural History]
* [http://www.avianbiotech.com/Index.htm| Avian Biotech]
* [http://www.tolweb.org/Palaeognathae/15837 Paleognathae on the Tree of Life Web Project]
* [http://www.agmrc.org/agmrc/commodity/livestock/ostrichemu/| Page on Ratites as Livestock]