Unenlagia [1] ( lat. Unenlagia ) is a genus of dinosaurs from the dromaeosaurid family that lived in the middle of the Cretaceous ( 93.5–85.8 Ma ) in the territory of modern Argentina . In the genus include 2 species: Unenlagia comahuensis and Unenlagia paynemili [2] .
| † Unenlagia |
Appearance reconstruction |
| Scientific classification |
|---|
| No rank : | Bilateral symmetric |
| Infraclass : | Archosauromorphs |
| No rank : | Archosauriformes |
| Group : | † Maniraptoriformes |
|
| International Scientific Name |
|---|
Unenlagia Novas & Puerta, 1997 |
| Kinds |
|---|
- † Unenlagia comahuensis
Novas & Puerta, 1997 typus - † Unenlagia paynemili
Calvo et al. , 2004
|
Geochronology93.5—85.8 Ma | million years | Period | Era | Eon |
|---|
| 2.588 | Even | | | Ka | F
but
n
e
R
about
s
about
th | | 23.03 | Neogene | | 66.0 | Paleogene | | 145.5 | a piece of chalk | M
e
s
about
s
about
th | | 199.6 | Yura | | 251 | Triassic | | 299 | Permian | P
but
l
e
about
s
about
th | | 359.2 | Carbon | | 416 | Devonian | | 443.7 | Silur | | 488.3 | Ordovician | | 542 | Cambrian | | 4570 | Precambrian |
◄ Nowadays◄ Cretaceous-Paleogene extinction◄ Triassic extinction◄ Perm mass extinction◄ Devonian extinction◄ Ordovician-Silurian extinction◄ Cambrian explosion |
|---|
|
Content
Famous skeletal fragments of
U. comahuensis In 1996, a skeleton of a theropod was discovered in the Argentine province of Neuquen , which was reported in the same year [3] . In 1997, Fernando Emilio Novas and Pablo Puerta named and described the species Unenlagia comahuensis . The name of the genus comes from the phrase in the language Mapuche uñen + lag - “half-bird”, since the authors of the article considered the animal as a transitional link between basal theropods and birds. The species name refers to the Comahue region where the fossils were found [4] .
A sample of the holotype , MCF PVPH 78, was found in the layers of , which dates from the Cognac century of the Cretaceous period. The holotype is a well-preserved partial skeleton without a skull, including vertebrae , sacrum , chevrons , ribs , scapula , humerus , fragments of the pelvis , bones of the thigh and lower leg [4] .
U. paynemili fossils. Currently, it is believed that the claw was on the forelimb, and not on the back, as shown in the photo
In 2002, a second skeleton was found near Lago Barreles, which was reported in 2003 [5] . The following year, in 2004, paleontologists , Juan Porfiri and described him as the second type of Unenlagia paynemili . The species name is given in honor of Maximo Pinemille. The holotype is an incomplete skeleton, including the humerus and two pelvic bones. The authors of the work described several paratypes : MUCPv-343, claw; MUCPv-409, a fragment of the Ilium ; MUCPv-415, phalanx of the finger, and MUCPv-416, vertebra [6] .
Some researchers consider the Neuquenraptor to be the subjective younger synonym for Unnlagia [7] .
There were controversies around the body size of the unlaglagi because only the limb length of the animal is well known, and it is unclear whether to extrapolate it using proportions of more advanced dromaeosaurids or long-legged basal birds. The scores thus varied between a length of 3.5 meters and a weight of 75 kilograms, on the one hand [8] , and a length of only 2 meters, on the other [9] . In the same way, the interpretation of the shape of the head from the short and high inherent to dromaeosaurids to a more elongated shape, characteristic of later discovered Buitreraptor and Austroraptor , has changed.
Novas and Puerta found that the pelvic region of the unlagia, especially the shape of the ileum, was very similar to that of Archeopteryx [4] . The upper arm of the Unlagia was originally described as adapted for flapping movements — with a flat shoulder blade located on the top of the rib cage, which made the point of attachment of the shoulder joint more lateral . However, in 2002, Kenneth Carpenter noted that this would mean that the scapula was flattened dorsoventrally , rather than laterally, like other theropods, and therefore the scapula is more likely to be located on the side of the chest [10] . This assumption supported the hypothesis of Philip Center that non-claudian Avialae were not able to lift limbs above their own backs, while the more primitive Archeopteryx could do this [11] . However, South American paleontologists remained adamant, stating that a transverse blade would press a coracoid into the chest, which would be anatomically implausible [9] .
With a body size of 3 meters, the unenlagia was hardly able to fly.
In the first description, Novas and Puerta considered Unenlagia a sister taxon of birds, which made it the basal representative of the clade Avialae sensu Gauthier 1986 [3] .
However, in 1999 Marc Norell and Peter Mackowitzi stated that the unnlagia was a member of the dromaeosaurid family [12] [13] . Unenlagia belonged to the Gondwanian dromaeosaurid hoard, called Unenlagiinae, and was closely associated with species such as Buitreraptor and Neuquenraptor (which could be the same taxon with Unlagia). In 2005, Makovicki et al. Also restored the “flying predator” Rahonavis as a member of this group. This meant that either the unenlagia lost its evolutionary ability to fly, although it developed from the ancestors of Rahonavis- like ancestors, or that the ability to fly appeared twice in the process of evolution [14] . Norell et al. Also discovered in 2006 that Rahonavis was a sister taxon for the unlagia [15] .
Not all researchers agree with this position. In 2011, Fernando Novas and Federico Agnoln published a study in which they located the subfamily Unenlagiidae within the clade Avialae [16] .
- ↑ Kurochkin E. N., Lopatin A. V. Fossil vertebrates in Russia and adjacent countries. Fossil reptiles and birds. Part 2 / Lopatin A.V. - M .: Geos, 2012. - V. 2. - P. 207. - 419 (154 images, 26 phototables) p. - ISBN 978-5-89118-594-4 .
- ↑ Unenlagia (English) information on the Paleobiology Database site. (Verified January 3, 2018)
- ↑ 1 2 Novas FE, Cladera G., Puerta P. New theropods from the Late Cretaceous of Patagonia (Eng.) // Journal of Vertebrate Paleontology . - 1996. - Vol. 16 , no. 3 - P. 56A . - DOI : 10.1080 / 02724634.1996.10011371 .
- 2 1 2 3 Novas FE, Puerta PF New evidence for the origins of the Late Cretaceous of Patagonia (Eng.) // Nature . - 1997. - Vol. 387 , no. 6631 . P. 390-392 .
- ↑ Calvo JO, Porfiri JD, Kellner AWA A close relative of the Unenlagia comahuensis (Theropoda, Maniraptora) from the Upper Cretaceous of Neuquén, Patagonia, Argentina (English) // 18º Congresso Brasileiro de Paleontologia, Brasilia, Resumos. - 2003. - P. 82-83 .
- ↑ Calvo JO, Porfiri JD, Kellner AWA on the New Cretaceous of Neuquén, Patagonia, Argentina (Eng.) // Arq. Mus. Nacional. Rio de Janeiro. - 2004. - Vol. 62 . - P. 549-566 .
- ↑ Turner AH, Hwang SH, Norell MA A small derived theropod from Öösh, Early Cretaceous, Baykhangor Mongolia (Eng.) // American Museum Novitates. - 2007. - Vol. 3557 . - P. 1—27 .
- GS Paul GS The Princeton Field Guide to Dinosaurs. - Princeton University Press, 2010. - p. 138.
- ↑ 1 2 Gianechini FA, Apesteguia S. Unenlagiinae revisited: dromaeosaurid theropods from South America (Eng.) // Anais da Academia Brasileira de Ciencias. - 2011. - Vol. 83 , no. 1 . - P. 163-195 .
- ↑ Carpenter K. Forelimb biomechanics of the nonavian theropod dinosaurs in predation (Eng.) // Senckenbergiana Lethaea. - 2002. - Vol. 82 - P. 59-76 .
- Enter Senter P. Scapular orientation and flaming flight (Eng.) // Acta Palaeontologica Polonica. - 2006. - Vol. 51 , no. 2 - P. 305-313 .
- ↑ Norell MA, Makovicky PJ : Information from the newly selected specimens of Velociraptor mongoliensis (Eng.) // American Museum Novitates. - 1999. - Vol. 3282 . - P. 1-45 .
- ↑ Norell MA, Makovicky PJ Dromaeosauridae // The Dinosauria (second edition) / DB Weishampel, P. Dodson, H. Osmolska. - Berkeley: University of California Press, 2004. - p. 196–209.
- ↑ Makovicky, Peter J .; Apesteguía, Sebastián; Agnolín, Federico L. The Earliest Dromaeosaurid Theropod from South America (Eng.) // Nature. - 2005. - Vol. 437 , no. 7061 . - P. 1007-1011 . - DOI : 10.1038 / nature03996 . (inaccessible link)
- ↑ Norell MA, Clark JM, Turner AH, Makovicky PJ, Barsbold R., Rowe T. A new dromaeosaurid theropod from Ukhaa Tolgod (Omnogov, Mongolia) (English) // American Museum Novitates. - 2006. - Vol. 3545 . - P. 1-51 . - DOI : 10.1206 / 0003-0082 (2006) 3545 [1: ANDTFU] 2.0.CO; 2 .
- ↑ Agnolin FL, Novas FE Unenlagiid theropods: are they members of the Dromaeosauridae (Theropoda, Maniraptora)? (English) // Anais da Academia Brasileira de Ciências. - 2011. - Vol. 83 , no. 1 . P. 117-162 . - DOI : 10.1590 / S0001-37652011000100008 .
