Zapalasaurus

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Zapalasaurus
Temporal range: Barremian-Early Aptian
~130–120  Ma
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Clade: Saurischia
Clade:† Sauropodomorpha
Clade:† Sauropoda
Superfamily:† Diplodocoidea
Family:† Rebbachisauridae
Genus:† Zapalasaurus
Salgado et al., 2006
Type species
Zapalasaurus bonapartei
Salgado et al., 2006

Zapalasaurus is an extinct genus of sauropod dinosaur from the Early Cretaceous-aged La Amarga Formation of what is today Patagonia. The type and only species is Z. bonapartei. [1]

Contents

Discovery and naming

The fossils which would eventually be named Zapalasaurus were discovered in 1995 at a locality called Puesto Morales. This corresponds to the Piedra Parada Member of the La Amarga Formation. The specimen was excavated from 1995-1996 by scientists associated with the Bernardino Rivadavia Natural Sciences Argentine Museum and the Juan A. Olsacher Museum under the leadership of the famous Argentine paleontologist José F. Bonaparte. Additional remains of this specimen were later excavated in 2004 by the Geology and Paleontology Museum of the National University of Comahue. The specimen was given the designation Pv-6127-MOZ. It was described and named in 2006 by a team of scientists led by Leonardo Salgado. Zapalasaurus was named after the city of Zapala, which is approximately 80 kilometres (50 mi) away from where the holotype was discovered. The species epithet was given in honor of Dr. José Bonaparte, who was an important Argetine paleontologist in the 20th century. [1]

Description

The holotype of Zapalasaurus consists of a single vertebrae from the middle of the neck, a fragment of a sacral vertebra, 17 caudal vertebrae, the left ischium and pubis, a fragment of an ilium, a partial left femur, and the left tibia. Zapalasaurus can be distinguished from other diplodocoids based on several features of the cervical neural arches as well as caudal vertebrae which double in length from front to back. [1]

Zapalasaurus is assumed to have a long neck which would have been developed for feeding adaption, allowing its neck to swing in an arc like shape. This would allow Zapalasaurus to browse a wide variety of plants and greens without having to walk very far. [2] [3]

Classification

In their original description, Salgado and colleagues found Zapalasaurus to be a basally-branching diplodocoid outside of any of the major subgroups. [1] However, subsequent analyses have found it to be a member of Rebbachisauridae. A cladogram published by Carballido and colleagues in their description of Comahuesaurus is shown below. [4]

Rebbachisauridae

Paleoenvironment

Zapalasaurus was discovered in sedimentary rocks of the La Amarga Formation, which is part of the Neuquén Basin and dates to the Barremian and late Aptian of the Early Cretaceous. Most vertebrate fossils, including Zapalasaurus, have been found in the lowermost (oldest) part of the formation, the Puesto Antigual Member. This member is approximately 29 meters (95 ft) in thickness and mainly composed of sandstones deposited by braided rivers. [5] The sauropod fauna of the La Amarga Formation was diverse and included the dicraeosaurids Amargasaurus and Amargatitanis , and unnamed remains of basal titanosauriforms. [6] The high diversity suggests that different sauropod species exploited different food sources in order to reduce competition. Basal titanosauriforms showed proportionally longer necks, longer forelimbs, and broader tooth crowns than dicraeosaurids and rebbachisaurids, suggesting greater feeding heights. [7] Amargatitanis and Amargasaurus probably fed above ground level at heights of up to 2.7 meters (8.9 ft), as evidenced by the anatomy of their neck and inner ear. Rebbachisaurids like Zapalasaurus presumably fed at ground-level, while basal Titanosauriforms exploited food sources at higher levels. [7]

Other dinosaurs of the La Amarga Formation include an indeterminate stegosaur; predatory dinosaurs include the small ceratosaur Ligabueino , and the presence of a large tetanuran is indicated by teeth. [8] Other than dinosaurs, the formation is notable for the cladotherian mammal Vincelestes , the only mammal known from the Early Cretaceous of South America. [9] Crocodylomorphs are represented by the trematochampsid Amargasuchus. [10]

See also

References

  1. 1 2 3 4 Salgado, Leonardo; Carvalho, Ismar de Souza; Garrido, Alberto C. (2006). "Zapalasaurus bonapartei, un nuevo dinosaurio saurópodo de La Formación La Amarga (Cretácico Inferior), noroeste de Patagonia, Provincia de Neuquén, Argentina" . Geobios. 39 (5): 695–707. Bibcode:2006Geobi..39..695S. doi:10.1016/j.geobios.2005.06.001. ISSN   0016-6995.
  2. ↑ Paul C. Sereno; Jeffrey A. Wilson; Lawrence M. Witmer; John A. Whitlock; Abdoulaye Maga; Oumarou Ide; Timothy A. Rowe (2007). "Structural Extremes in a Cretaceous Dinosaur". PLOS ONE. 2 (11): e1230. Bibcode:2007PLoSO...2.1230S. doi: 10.1371/journal.pone.0001230 . PMC   2077925 . PMID   18030355.
  3. ↑ Fidel Torcida Fernández-Baldor; José Ignacio Canudo; Pedro Huerta; Diego Montero; Xabier Pereda Suberbiola & Leonardo Salgado (2011). "Demandasaurus darwini, a new rebbachisaurid sauropod from the Early Cretaceous of the Iberian Peninsula". Acta Palaeontologica Polonica. 56 (3): 535–552. doi: 10.4202/app.2010.0003 .
  4. ↑ Carballido, José Luis; Salgado, Leonardo; Pol, Diego; Canudo, José Ignacio; Garrido, Alberto (2012). "A new basal rebbachisaurid (Sauropoda, Diplodocoidea) from the Early Cretaceous of the Neuquén Basin; evolution and biogeography of the group". Historical Biology. 24 (6): 631–654. Bibcode:2012HBio...24..631C. doi:10.1080/08912963.2012.672416. S2CID   130423764.
  5. ↑ Leanza, Héctor A; Apesteguı́a, Sebastián; Novas, Fernando E; de la Fuente, Marcelo S (2004-02-01). "Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages" . Cretaceous Research. 25 (1): 61–87. Bibcode:2004CrRes..25...61L. doi:10.1016/j.cretres.2003.10.005. ISSN   0195-6671. Archived from the original on 2020-03-18. Retrieved 2023-08-20.
  6. ↑ Windholz, Guillermo J.; Baiano, Mattia A.; Bellardini, Flavio; Garrido, Alberto (2021-01-01). "New Dicraeosauridae (Sauropoda, Diplodocoidea) remains from the La Amarga Formation (Barremian–Aptian, Lower Cretaceous), Neuquén Basin, Patagonia, Argentina" . Cretaceous Research. 117: 104629. Bibcode:2021CrRes.11704629W. doi:10.1016/j.cretres.2020.104629. ISSN   0195-6671.
  7. 1 2 Paulina Carabajal, Ariana; Carballido, José L.; Currie, Philip J. (2014-06-07). "Braincase, neuroanatomy, and neck posture of Amargasaurus cazaui (Sauropoda, Dicraeosauridae) and its implications for understanding head posture in sauropods". Journal of Vertebrate Paleontology. 34 (4): 870–882. Bibcode:2014JVPal..34..870P. doi:10.1080/02724634.2014.838174. hdl: 11336/19365 . ISSN   0272-4634. Archived from the original on 2022-12-20. Retrieved 2023-08-20.
  8. ↑ Ezcurra, Martin Daniel; Novas, Fernando Emilio (2016). "Theropod dinosaurs from Argentina". Museo Argentino de Ciencias Naturales Bernardino Rivadavia. ISSN   1666-5503. Archived from the original on 2023-08-15. Retrieved 2023-08-20.
  9. ↑ Bonaparte, José F. (2008). "On the phylogenetic relationships of Vincelestes neuquenianus: Short Review" . Historical Biology. 20 (2): 81–86. doi:10.1080/08912960802164470. ISSN   0891-2963. Archived from the original on 2023-08-15. Retrieved 2023-08-20.
  10. ↑ Chiappe, Luis M. (1988-12-01). "A new trematochampsid crocodile from the Early Cretaceous of north-western Patagonia, Argentina and its palaeobiogeographical and phylogenetic implications" . Cretaceous Research. 9 (4): 379–389. Bibcode:1988CrRes...9..379C. doi:10.1016/0195-6671(88)90009-2. ISSN   0195-6671.
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