Hispanopedia Wiki
Articulo de referencia

Zhenyuanopterus

Zhenyuanopterus es un género de pterosaurio boreoptérido conocido de la Formación Yixian del Cretácico Inferior ( etapa Aptiense temprana )de Liaoning , China . Contiene una esp...

Hispanopedia WikiContenido en espanolLectura gratuita

Zhenyuanopterus es un género de pterosaurio boreoptérido conocido de la Formación Yixian del Cretácico Inferior ( etapa Aptiense temprana )de Liaoning , China . Contiene una especie, Zhenyuanopterus longirostris , que fue descrita y nombrada por primera vez por Lü Junchang . [ 1 ]

Descubrimiento y denominación

Zhenyuanopterus longirostris fue nombrado por el paleontólogo Lü Junchang en 2005. El género lleva el nombre de Sun Zhenyuan, quien le entregó los fósiles a Lü Junchang junto con Zi Fan. El nombre específico ("hocico largo") hace referencia al hocico alargado del pterosaurio. Se conoce un espécimen; un esqueleto completo, encontrado en la localidad de Huangbanjigou de la Formación Yixian , y catalogado como GLGMV 0001 en el Museo Geológico Guilin Longshan en Guangxi , China. [ 1 ] Un segundo espécimen parcial, de mayor tamaño, que consiste en la mitad posterior del cuerpo, fue encontrado en la misma localidad y catalogado como XHPM1088 en el Museo Paleontológico Dalian Xinghai. En 2014, Teng Fangfang y sus colegas lo describieron. [ 2 ]

Descripción

El cráneo del espécimen tipo de Zhenyuanopterus mide 54,5 centímetros (21,5 pulgadas) de largo. Posee una cresta rectangular que se extiende a lo largo de la parte superior del hocico y otra pequeña cresta en la parte posterior de la cabeza. La órbita ocular tiene forma de triángulo invertido. Típico de los Boreopteridae , Zhenyuanopterus tenía un hocico largo lleno de dientes en forma de aguja, que son los más largos en la parte frontal de la boca; una característica distintiva es que los dientes más largos son más de 10 veces más largos que los más cortos. Los dientes son lisos y triangulares, con una ligera curva. Hay 86 dientes en la mandíbula superior y otros 86 en la inferior. [ 1 ] [ 3 ] [ 4 ] 

Additional distinguishing characteristics include the third phalanx of the wing digit, the humerus, and femur having the same length; and the feet being very small.[1] The second specimen indicated that the humerus and femur grew at the same rate. The forelimb was more robust than the hindlimb. It was thought that the coracoid was longer than the scapula or shoulder blade, unlike most advanced pterosaurs, but the type specimen had a poorly-preserved coracoid and the second specimen showed this to not be the case.[2]Zhenyuanopterus had relatively short cervical vertebrae compared to Feilongus. Several of the dorsal vertebrae are fused into a notarium,[1] an indicator of maturity.[3]

Zhenyuanopterus was estimated to have a wingspan of 3.5 to 4 meters (11 to 13 ft), making it one of the larger boreopterids.[1][3]

Synonymy with Boreopterus

Boreopterus and Zhenyuanopterus are both part of the Boreopteridae, and occur in the same depositional unit. Lü distinguished the two based on the greater number of teeth, the shorter mandibular symphysis, and equal-length third wing finger phalanx, humerus, and femur in Zhenyuanopterus.[1] However, it has been suggested that this animal is actually the adult of Boreopterus, which is known to be a juvenile; all known specimens of the crestless Boreopterus are smaller than the large, crested Zhenyuanopterus, and most of the differences between them can be explained as age-related. Boreopterus may have been too young to develop a crest when it died.[3]

Classification

Lü classified Zhenyuanopterus in the Boreopteridae based on the long and low skull, long and sharp teeth, long front teeth, and the femur and tibia being of equal length.[1] In 2012, he further subdivided Boreopteridae by allying Zhenyuanopterus and Boreopterus in the Boreopterinae, based on the tooth row extending further back on the jaw, the shorter cervical vertebrae, and the weaker feet of these two genera.[5] This concept was later followed by Brian Andres and colleagues, while also placing Guidraco as a basal member of the family.[6] However, Jiang Shun-Xing later restricted Boreopteridae to Zhenyuanopterus and Boreopterus after finding that Lü's definition was not monophyletic.[7] In 2018, a later study by Nicholas Longrich and colleagues found the Boreopteridae (consisting only of Boreopterus and Zhenyuanopterus) as the sister taxon of the family Lonchodectidae, while also placed as members of the more inclusive group Ornithocheiromorpha.[8]

Paleoecology

In the Yixian Formation, Zhenyuanopterus lived with other pterosaurs such as Boreopterus, Feilongus, Haopterus, Yixianopterus, and Gegepterus.[1] Teng and colleagues suggested in 2014 that Zhenyuanopterus spent less time on land and more time in the air or on cliffs, owing to the robust forelimbs and weak hindlimbs.[2]

Diet

The Yixian Formation in the early Cretaceous was a lakeside forest ecosystem with the presence of volcanoes. These lakes and waterways would have provided many aquatic prey, like fish and amphibians, that Zhenyuanopterus would have likely hunted.[9] It has been suggested that Zhenyuanopterus foraged while swimming, trapping prey within its needle-like teeth, a method similar to that of modern Platanista river dolphins, which display a similar dentition.[3]

See also

References

  1. 123456789Lü, J. (2010). "A new boreopterid pterodactyloid pterosaur from the Early Cretaceous Yixian Formation of Liaoning Province, northeastern China". Acta Geologica Sinica. 24 (2): 241–246. Bibcode:2010AcGlS..84..241L. doi:10.1111/j.1755-6724.2010.00204.x. S2CID 140600398.
  2. 123Teng, F.; Lü, J.; Wei, X.; Hsiao, Y.; Pittman, M. (2014). "New Material of Zhenyuanopterus (Pterosauria) from the Early Cretaceous Yixian Formation of Western Liaoning". Acta Geologica Sinica. 88 (1): 1–5. Bibcode:2014AcGlS..88....1T. doi:10.1111/1755-6724.12176. S2CID 128886125.
  3. 12345Witton, Mark P. (2013). "Boreopteridae". Pterosaurs: Natural History, Evolution, Anatomy. Princeton, NJ: Princeton University Press. pp. 164–169. ISBN 978-0-691-15061-1.
  4. ↑Naish, Darren (April 19, 2010). "Zhenyuanopterus, Boreopterus and the Ask A Biologist relaunch". ScienceBlogs. Retrieved May 7, 2019.
  5. ↑Lü, J.; Pu, Hanyong; Xu, L.; Wu, Y.; Wei, X. (2012). "Largest Toothed Pterosaur Skull from the Early Cretaceous Yixian Formation of Western Liaoning, China, with Comments On the Family Boreopteridae". Acta Geologica Sinica. 86 (2): 287–293. Bibcode:2012AcGlS..86..287L. doi:10.1111/j.1755-6724.2012.00658.x. S2CID 130163272.
  6. 12Andres, B.; Clark, J.; Xu, X. (2014). "The Earliest Pterodactyloid and the Origin of the Group". Current Biology. 24 (9): 1011–6. Bibcode:2014CBio...24.1011A. doi:10.1016/j.cub.2014.03.030. PMID 24768054.
  7. ↑Jiang, S.-X.; Wang, X.-L.; Meng, X.; Cheng, X. (2014). "A new boreopterid pterosaur from the Lower Cretaceous of western Liaoning, China, with a reassessment of the phylogenetic relationships of the Boreopteridae". Journal of Paleontology. 88 (4): 823–828. Bibcode:2014JPal...88..823J. doi:10.1666/13-068. S2CID 128515924.
  8. 12Longrich, Nicholas R.; Martill, David M.; Andres, Brian (2018). "Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary". PLOS Biology. 16 (3) e2001663. doi:10.1371/journal.pbio.2001663. PMC 5849296. PMID 29534059.
  9. ↑Lacerda, Julio. "Zhenyuanopterus". Pteros. Retrieved May 6, 2019.