Avisauridae
Encyclopedia
The Avisauridae are a family of extinct Enantiornithine birds known from Cretaceous
North and South America. They are represented by eight genera
.
Avisauridae was erected by Brett-Surman and Paul in 1985. They included in this Family
a few fossils that they believed belonged to small non — avian dinosaurs.
Chiappe (1992) later reassigned the Avisauridae to the Class
Aves and the Subclass
Enantiornithes
. Chiappe (1993) diagnosed the Family as "Enantiornithine birds with a strong transverse convexity of the dorsal surface of the mid — shaft of metatarsal III, a distinct plantar projection of the medial rim of the trochlea of Metatarsal III, and a laterally compressed J-shaped metatarsal I." He defined the Family as the common ancestor of Neuquenornis volans
and Avisaurus archibaldi
plus all its descendants. In 2008, the Family was redefined as Avisaurus archibaldi
and all genera more closely related to it than to either Longipteryx
, Gobipteryx
or Sinornis.
Cladogram
based on Cau and Arduini (2008):
Chiappe and Calvo (1994) found that the Avisauridae shared adaptations of the foot — including a fully reversed and distally placed hallux
with a large claw — that indicated the ability to perch in trees. They argued that an arboreal habit was most likely for all of the Avisauridae.
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
North and South America. They are represented by eight genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
.
Avisauridae was erected by Brett-Surman and Paul in 1985. They included in this Family
Family
In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...
a few fossils that they believed belonged to small non — avian dinosaurs.
Chiappe (1992) later reassigned the Avisauridae to the Class
Class (biology)
In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
Aves and the Subclass
Class (biology)
In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
Enantiornithes
Enantiornithes
Enantiornithes is an extinct group of primitive birds. They were the most abundant and diverse avialans of the Mesozoic. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over 50 species of Enantiornithines have been named, but some...
. Chiappe (1993) diagnosed the Family as "Enantiornithine birds with a strong transverse convexity of the dorsal surface of the mid — shaft of metatarsal III, a distinct plantar projection of the medial rim of the trochlea of Metatarsal III, and a laterally compressed J-shaped metatarsal I." He defined the Family as the common ancestor of Neuquenornis volans
Neuquenornis
Neuquenornis volans was an enantiornithine bird which lived during the Late Cretaceous in today's Patagonia, Argentina. It is presently the only known species of the genus Neuquenornis. Its fossils were found in the Santonian Bajo de la Carpa Formation, dating from about 85-83 million years ago....
and Avisaurus archibaldi
Avisaurus
Avisaurus is a genus of enantiornithine bird from the Late Cretaceous of North America.Two species are known; the type species A. archibaldi and A. gloriae...
plus all its descendants. In 2008, the Family was redefined as Avisaurus archibaldi
Avisaurus
Avisaurus is a genus of enantiornithine bird from the Late Cretaceous of North America.Two species are known; the type species A. archibaldi and A. gloriae...
and all genera more closely related to it than to either Longipteryx
Longipteryx
Longipteryx is a genus of prehistoric bird which lived during the Early Cretaceous . It contains a single species, Longipteryx chaoyangensis. Its remains have been recovered from the Jiufotang Formation at Chaoyang in Liaoning Province, People's Republic of China...
, Gobipteryx
Gobipteryx
Gobipteryx is the name given to a genus of enantiornithine bird from the Late Cretaceous Period. Its fossils were found in the Barun Goyot Formation in the Gobi Desert, Mongolia and first described in 1976 from two fragmentary skulls...
or Sinornis.
Cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
based on Cau and Arduini (2008):
Chiappe and Calvo (1994) found that the Avisauridae shared adaptations of the foot — including a fully reversed and distally placed hallux
Hallux
In tetrapods, the hallux is the innermost toe of the foot. Despite its name it may not be the longest toe on the foot of some individuals...
with a large claw — that indicated the ability to perch in trees. They argued that an arboreal habit was most likely for all of the Avisauridae.