Eosinopteryx

Last updated

Contents

Eosinopteryx
Temporal range: Late Jurassic, 160  Ma
O
S
D
C
P
T
J
K
Pg
N
Eosinopteryx.jpg
Life restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Anchiornithidae
Genus: Eosinopteryx
Godefroit et al., 2013
Type species
Eosinopteryx brevipenna
Godefroit et al., 2013

Eosinopteryx is an extinct genus of theropod dinosaurs known to the Late Jurassic epoch of China. It contains a single species, Eosinopteryx brevipenna. [1]

Discovery and naming

E. brevipenna is known from a single fossil specimen recovered from the Tiaojishan Formation of western Liaoning Province, China, which has been dated to the late Jurassic period (Oxfordian age), about 160 million years ago. [2] [3] The name Eosinopteryx is derived from the Greek eos ("daybreak" or "dawn"), the Latin Sinae ("Chinese"), and the Greek pteryx ("feather"). The specific name brevipenna (from the Latin brevis, "short", and penna, "feather") refers to the reduced plumage preserved in the type specimen, YFGP-T5197. [1]

Description

Eosinopteryx brevipenna is known from a single fossil specimen representing the nearly complete skeleton of a subadult or adult individual. The specimen is very small for a non-avialan dinosaur, measuring about 30 centimetres (12 in) long. Unlike most troodontids, the snout was very short, shorter than the diameter of the eye socket. The wings were about the same size as those of the related Anchiornis huxleyi , with the primary wing feathers being longer than the humerus (upper arm bone). An unusual arrangement of the wing bones would have prevented any flapping motion.

The tail was very short compared to most troodontids and dromaeosaurids and also unlike members of those groups, the feet and toes were very slender, lacking highly curved claws for predation or climbing. Unusually, the tail of the only known fossil does not show signs of the presence of complex vaned feathers (rectrices), and the lower tarsals and feet appear to have been featherless, unlike many related species with "hind wings" on the lower legs and feet. [1]

A researcher from the University of Southampton said in 2013 the discovery of Eosinopteryx suggests "that the origin of flight was much more complex than previously thought". [4]

A 2017 study describing new specimens of Anchiornis found Eosinopteryx only distinguishable from Anchiornis in the length of the tail, [5] but the tail of Eosinopteryx is incomplete, [6] rendering this distinction invalid. This led some researchers to consider Eosinopteryx a junior synonym of Anchiornis. [7]

Classification

Though initially classified as a troodontid, [1] a more comprehensive analyses of its relationships have found it to be either a primitive paravian or an avialan. [8] In 2017 re-evaluation of the Harlem Archaeopteryx specimen, Eosinopteryx is found to be an anchiornithid. [9]

Related Research Articles

<i>Archaeopteryx</i> Extinct genus of bird-like dinosaurs

Archaeopteryx, sometimes referred to by its German name, "Urvogel" is a genus of bird-like dinosaurs. The name derives from the ancient Greek ἀρχαῖος (archaīos), meaning "ancient", and πτέρυξ (ptéryx), meaning "feather" or "wing". Between the late 19th century and the early 21st century, Archaeopteryx was generally accepted by palaeontologists and popular reference books as the oldest-known bird. Older potential avialans have since been identified, including Anchiornis, Xiaotingia, and Aurornis.

<span class="mw-page-title-main">Troodontidae</span> Extinct family of bird-like dinosaurs

Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discoveries of complete and articulated specimens, have helped to increase understanding about this group. Anatomical studies, particularly studies of the most primitive troodontids, like Sinovenator, demonstrate striking anatomical similarities with Archaeopteryx and primitive dromaeosaurids, and demonstrate that they are relatives comprising a clade called Paraves.

<span class="mw-page-title-main">Deinonychosauria</span> Extinct clade of dinosaurs

Deinonychosauria is a clade of paravian dinosaurs which lived from the Late Jurassic to the Late Cretaceous periods. Fossils have been found across the globe in North America, Europe, Africa, Asia, South America, and Antarctica, with fossilized teeth giving credence to the possibility that they inhabited Australia as well. This group of dinosaurs are known for their sickle-shaped toe claws and features in the shoulder bones.

<i>Jinfengopteryx</i> Theropod dinosaur genus

Jinfengopteryx is a genus of maniraptoran dinosaur. It was found in the Qiaotou Member of the Huajiying Formation of Hebei Province, China, and is therefore of uncertain age. The Qiaotou Member may correlate with the more well-known Early Cretaceous Yixian Formation, and so probably dates to around 122 Ma ago.

<i>Yixianosaurus</i> Extinct genus of dinosaurs

Yixianosaurus is a maniraptoran theropod dinosaur genus from the Early Cretaceous of China.

<span class="mw-page-title-main">Scansoriopterygidae</span> Extinct family of dinosaurs

Scansoriopterygidae is an extinct family of climbing and gliding maniraptoran dinosaurs. Scansoriopterygids are known from five well-preserved fossils, representing four species, unearthed in the Tiaojishan Formation fossil beds of Liaoning and Hebei, China.

<i>Yandangornis</i> Extinct genus of dinosaurs

Yandangornis is a genus of theropods from the Late Cretaceous Tangshang Formation of China. It lived 81.5 million years ago in what is now China. The type species, Y. longicaudus, was formally described by Cai and Zhou in 1999.

<span class="mw-page-title-main">Maniraptoriformes</span> Clade of dinosaurs

Maniraptoriformes is a clade of dinosaurs with pennaceous feathers and wings that contains ornithomimosaurs and maniraptorans. This group was named by Thomas Holtz, who defined it as "the most recent common ancestor of Ornithomimus and birds, and all descendants of that common ancestor."

<span class="mw-page-title-main">Avialae</span> Clade including all birds and their ancestors

Avialae is a clade containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally used.

<span class="mw-page-title-main">Paraves</span> Clade of all dinosaurs that are more closely related to birds than to oviraptorosaurs

Paraves are a widespread group of theropod dinosaurs that originated in the Middle Jurassic period. In addition to the extinct dromaeosaurids, troodontids, anchiornithids, and possibly the scansoriopterygids, the group also contains the avialans, which include diverse extinct taxa as well as the over 10,000 species of living birds. Basal members of Paraves are well known for the possession of an enlarged claw on the second digit of the foot, which was held off the ground when walking in some species. A number of differing scientific interpretations of the relationships between paravian taxa exist. New fossil discoveries and analyses make the classification of Paraves an active subject of research.

<i>Epidexipteryx</i> Extinct genus of dinosaurs

Epidexipteryx is a genus of small paravian dinosaurs, known from one fossil specimen in the collection of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. Epidexipteryx represents the earliest known example of ornamental feathers in the fossil record.

<i>Anchiornis</i> Extinct genus of dinosaurs

Anchiornis is a genus of small, four-winged paravian dinosaurs, with only one known species, the type species Anchiornis huxleyi, named for its similarity to modern birds. The Latin name Anchiornis derives from a Greek word meaning "near bird", and huxleyi refers to Thomas Henry Huxley, a contemporary of Charles Darwin.

<i>Xiaotingia</i> Extinct genus of dinosaurs

Xiaotingia is a genus of anchiornithid theropod dinosaur from Middle Jurassic or early Late Jurassic deposits of western Liaoning, China, containing a single species, Xiaotingia zhengi.

<i>Aurornis</i> Extinct genus of dinosaurs

Aurornis is an extinct genus of anchiornithid theropod dinosaurs from the Jurassic period of China. The genus Aurornis contains a single known species, Aurornis xui. Aurornis xui may be the most basal ("primitive") avialan dinosaur known to date, and it is one of the earliest avialans found to date. The fossil evidence for the animal pre-dates that of Archaeopteryx lithographica, often considered the earliest bird species, by about 10 million years.

<i>Jianianhualong</i> Extinct genus of dinosaurs

Jianianhualong is a genus of troodontid theropod dinosaur from the Early Cretaceous of China. It contains a single species, Jianianhualong tengi, named in 2017 by Xu Xing and colleagues based on an articulated skeleton preserving feathers. The feathers at the middle of the tail of Jianianhualong are asymmetric, being the first record of asymmetrical feathers among the troodontids. Despite aerodynamic differences from the flight feathers of modern birds, the feathers in the tail vane of Jianianhualong could have functioned in drag reduction whilst the animal was moving. The discovery of Jianianhualong supports the notion that asymmetrical feathers appeared early in the evolutionary history of the Paraves.

<i>Liaoningvenator</i> Extinct genus of dinosaurs

Liaoningvenator is a genus of troodontid theropod dinosaur from the Early Cretaceous of China. It contains a single species, L. curriei, named after paleontologist Phillip J. Currie in 2017 by Shen Cai-Zhi and colleagues from an articulated, nearly complete skeleton, one of the most complete troodontid specimens known. Shen and colleagues found indicative traits that placed Liaoningvenator within the Troodontidae. These traits included its numerous, small, and closely packed teeth, as well as the vertebrae towards the end of its tail having shallow grooves in place of neural spines on their top surfaces.

<i>Serikornis</i> Extinct genus of dinosaurs

Serikornis is a genus of small, feathered anchiornithid dinosaur from the Upper Jurassic Tiaojishan Formation of Liaoning, China. It is represented by the type species Serikornis sungei.

<span class="mw-page-title-main">Anchiornithidae</span> Extinct family of dinosaurs

Anchiornithidae is a family of small paravian dinosaurs. Anchiornithids have been classified at varying positions in the paravian tree, with some scientists classifying them as a distinct family, a basal subfamily of Troodontidae, members of Archaeopterygidae, or an assemblage of dinosaurs that are an evolutionary grade within Avialae or Paraves.

<i>Caihong</i> Extinct genus of dinosaurs

Caihong is a genus of small paravian theropod dinosaur from China that lived during the Late Jurassic period.

References

  1. 1 2 3 4 Godefroit, P.; Demuynck, H.; Dyke, G.; Hu, D.; Escuillié, F. O.; Claeys, P. (2013). "Reduced plumage and flight ability of a new Jurassic paravian theropod from China". Nature Communications. 4: 1394. Bibcode:2013NatCo...4.1394G. doi: 10.1038/ncomms2389 . PMID   23340434.
  2. Hu, D.; Hou, L.; Zhang, L. & Xu, X. (2009). "A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus". Nature. 461 (7264): 640–643. Bibcode:2009Natur.461..640H. doi:10.1038/nature08322. PMID   19794491. S2CID   205218015.
  3. Liu Y.-Q.; Kuang H.-W.; Jiang X.-J.; Peng N.; Xu H.; Sun H.-Y. (2012). "Timing of the earliest known feathered dinosaurs and transitional pterosaurs older than the Jehol Biota". Palaeogeography, Palaeoclimatology, Palaeoecology. 323–325: 1–12. doi:10.1016/j.palaeo.2012.01.017.
  4. "Feathered dinosaur puts theory in doubt". 3 News NZ. January 25, 2013.
  5. Pei, Rui; Li, Quanguo; Meng, Qingjin; Norell, Mark A.; Gao, Ke-Qin (April 2017). "New Specimens of Anchiornis huxleyi (Theropoda: Paraves) from the Late Jurassic of Northeastern China". Bulletin of the American Museum of Natural History. 411: 1–67. doi:10.1206/0003-0090-411.1.1. ISSN   0003-0090. S2CID   90650697.
  6. Hu, Dongyu; Clarke, Julia A.; Eliason, Chad M.; Qiu, Rui; Li, Quanguo; Shawkey, Matthew D.; Zhao, Cuilin; D’Alba, Liliana; Jiang, Jinkai; Xu, Xing (2018-01-15). "A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution". Nature Communications. 9 (1): 217. doi:10.1038/s41467-017-02515-y. ISSN   2041-1723. PMC   5768872 . PMID   29335537.
  7. Agnolin, Federico L.; Motta, Matias J.; Brissón Egli, Federico; Lo Coco, Gastón; Novas, Fernando E. (2019). "Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview". Frontiers in Earth Science. 6. doi: 10.3389/feart.2018.00252 . hdl: 11336/130197 . ISSN   2296-6463.
  8. Lefèvre, U.; Hu, D.; Escuillié, F. O.; Dyke, G.; Godefroit, P. (2014). "A new long-tailed basal bird from the Lower Cretaceous of north-eastern China". Biological Journal of the Linnean Society. 113 (3): 790–804. doi: 10.1111/bij.12343 .
  9. Foth, C.; Rauhut, O.W.M. (2017). "Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs". BMC Evolutionary Biology. 17 (1): 236. doi: 10.1186/s12862-017-1076-y . PMC   5712154 . PMID   29197327.