Pulanesaura

Pulanesaura is an extinct genus of basal sauropod known from the Early Jurassic (late Hettangian to Sinemurian) Upper Elliot Formation of the Free State, South Africa. It contains a single species, Pulanesaura eocollum, known from partial remains of at least two subadult to adult individuals.[1]

Pulanesaura
Temporal range: Hettangian-Sinemurian,
~200 Ma
Pulanesaura eocollum
Skeletal restoration
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Clade: Anchisauria
Clade: Sauropoda
Genus: Pulanesaura
McPhee et al., 2015
Type species
Pulanesaura eocollum
McPhee et al., 2015

Discovery and naming

Pulanesaura quarry map
Quarry map

The remains of Pulanesaura were discovered in a small quarry in the farm Spion Kop 932 in the Senekal District of the Free State in 2004 by paleontologist Matthew Bonnan. The bones were excavated between 2004 and 2006, and studied by Blair McPhee as part of his dissertation since 2011. Pulanesaura was then described and named officially by Blair W. McPhee, Matthew F. Bonnan, Adam M. Yates, Johann Neveling and Jonah N. Choiniere in 2015 with the type species Pulanesaura eocollum. The generic name is derived from the Sesoth word for "rain-maker/bringer", Pulane, in reference to the heavy rain conditions under which the remains were collected, and the feminine form of the common dinosaur name suffix, saura, meaning "lizard" in Latin. The specific name is derived from Greek eo, meaning "dawn", and Latin collum, meaning "neck", in reference to Pulanesaura being a very basal sauropod not yet showing the most archetypal trait of more advanced sauropods - their very long necks.[1] Pulanesaura was one of eighteen dinosaur taxa from 2015 to be described in open access or free-to-read journals.[2]

Pulanesaura is known from partial remains of at least two subadult to adult individuals. The holotype, BP/1/6982, represents the front dorsal vertebra missing the tip of the neural spine. In addition the referred material consists of two isolated teeth, a middle cervical vertebra, five back vertebral arches, a single right dorsal rib, three tail vertebrae, a left clavicle, a distal right humerus, a left ulna, possibly the fourth right middle hand bone, three ischia, a left and a right shinbones, and two hindlimb first claws. The remains are considered to be conspecific with the holotype due to their close association (in an area of three to three and a half meters) in fine and stable sandstone, their consistent morphology, and the fact the same elements from different individuals show no conflict in traits. The remains were collected on the farm Spion Kop 932, in a quarry located just over a kilometer East-North East another dinosaur rich quarry in a higher stratigraphic position within the probably Sinemurian part of the upper Elliot Formation, that yielded the less advanced sauropodomorphs Aardonyx celestae and the much smaller Arcusaurus pereirabdalorum.[1]

Phylogeny

Pulanesaura in situ
Tibiae and ischium during excavation
Pulanesaura tooth
Tooth
Pulanesaura dorsal vertebra
The holotype, a front dorsal vertebra

Pulanesaura is a medium-sized transitional sauropodiform. A phylogenetic analysis resolved its position as either one of the least derived sauropods or as the sister taxon to Sauropoda, depending on the definition for Sauropoda used (node or stem based). The following cladogram is simplified after this analysis (members of bold taxa are not shown).[1]

 Plateosauria 

Ruehleia

Plateosauridae

 Massopoda 

Riojasauridae

Massospondylidae

 Sauropodiformes 

Yunnanosaurus

Jingshanosaurus

Seitaad

 Anchisauria 

Anchisaurus

Mussaurus

Aardonyx

Blikanasaurus

Melanorosaurus

 Sauropoda ? 

Antetonitrus

Lessemsaurus

Leonerasaurus

Gongxianosaurus

Pulanesaura

 Sauropoda ? 

Vulcanodon

Isanosaurus

Tazoudasaurus

Spinophorosaurus

Eusauropoda

Paleoecology

Spion Kop Farm fauna
Fauna from the upper Elliot Formation in Spion Kop Farm

Pulanesaura's posture and skeletal build indicate that the animal was a low browser, unlike the prosauropods it shared its habitat with. Studies by Blair McPhee et al. indicate that Pulanesaura is thought to have coexisted with other sauropodomorphs found in the same formation due to niche partitioning. Its flexible neck would have further allowed it to feed without moving its body very often and expending valuable energy; a trait that later sauropods would take to extreme lengths. Studies of the Upper Elliot Formation suggest that the environment was a predominantly arid floodplain where vegetation was concentrated most heavily around the river channels that flowed through the area, further allowing the coexistence of Pulanesaura with other sauropodomorphs such as Aardonyx and Arcusaurus.[1]

References

  1. ^ a b c d e Blair W. McPhee; Matthew F. Bonnan; Adam M. Yates; Johann Neveling; Jonah N. Choiniere (2015). "A new basal sauropod from the pre-Toarcian Jurassic of South Africa: evidence of niche-partitioning at the sauropodomorph–sauropod boundary?". Scientific Reports. 5: Article number 13224. doi:10.1038/srep13224. PMC 4541066. PMID 26288028.
  2. ^ "The Open Access Dinosaurs of 2015". PLOS Paleo.
Antetonitrus

Antetonitrus is a genus of sauropod dinosaur found in Early Jurassic rocks in South Africa. The only species is Antetonitrus ingenipes. As one of the oldest known sauropods, it is crucial for the understanding of the origin and early evolution of this group. It was a quadrupedal herbivore, like all of its later relatives, but shows primitive adaptations to use the forelimbs for grasping, instead of purely for weight support.

Averostra

Averostra, or "bird snouts", is a clade that includes most theropod dinosaurs that have a promaxillary fenestra (fenestra promaxillaris), an extra opening in the front outer side of the maxilla, the bone that makes up the upper jaw. Two groups of averostrans, the Ceratosauria and the Orionides, survived into the Cretaceous period. When the Cretaceous–Paleogene extinction event occurred, ceratosaurians and two groups of orionideans within the clade Coelurosauria, the Tyrannosauroidea and Maniraptoriformes, were still extant. Only one subgroup of maniraptoriformes, Aves, survived the extinction event and persisted to the present day.

Avetheropoda

Avetheropoda, or "bird theropods", is a clade that includes carnosaurians and coelurosaurs to the exclusion of other dinosaurs.

Blikanasaurus

Blikanasaurus cromptoni is a genus of sauropodomorph dinosaur from the late Triassic of South Africa. The generic name Blikanasaurus is derived from Greek, meaning “lizard from Blikana.” The species name cromptoni is taken from the surname of A.W. “Fuzz” Crompton, an American paleontologist who led numerous field expeditions in Elliot Formation outcrop localities in South Africa. Blikanasaurus is only known from partial hindlimb bones that were recovered from the lower Elliot Formation (LEF) in the Eastern Cape.

Cerapoda

Cerapoda ("ceratopsians and ornithopods") is a clade of the dinosaur order Ornithischia.

Dinosauriformes

Dinosauriformes is a clade of archosaurian reptiles that include the dinosaurs and their most immediate relatives. All dinosauriformes are distinguished by several features, such as shortened forelimbs and a partially to fully perforated acetabulum, the hole in the hip socket traditionally used to define dinosaurs. The oldest known member is Asilisaurus, dating to about 245 million years ago in the Anisian age of the middle Triassic period.

Ferganasaurus

Ferganasaurus was a genus of dinosaur first formally described in 2003 by Alifanov and Averianov. The type species is Ferganasaurus verzilini. It was a sauropod similar to Rhoetosaurus. The fossils were discovered in 1966 in Kyrgyzstan from the Balabansai Formation and date to the Callovian stage of the Middle Jurassic.

Gravisauria

Gravisauria is a clade of sauropod dinosaurs consisting of some genera, Vulcanodontidae and Eusauropoda.

Jingshanosaurus

Jingshanosaurus (meaning "Jingshan lizard") is a genus of sauropodomorph dinosaurs from the early Jurassic period.

Ledumahadi

Ledumahadi (meaning "a giant thunderclap" in Sesotho language) is a genus of lessemsaurid sauropodomorph dinosaur from the Early Jurassic Elliot Formation in Free State Province, South Africa. The type and only species is L. mafube, known from a singular incomplete postcranial specimen. A quadruped, it was one of the first giant sauropodomorphs, reaching a weight of around 12 tonnes (26,000 lb), despite not having evolved columnar limbs like its later huge relatives.

Lessemsaurus

Lessemsaurus is an extinct genus of sauropod dinosaur belonging to Lessemsauridae.

Neotheropoda

Neotheropoda (meaning "new theropods") is a clade that includes coelophysoids and more advanced theropod dinosaurs, and the only group of theropods who survived the Triassic–Jurassic extinction event. Yet all of the neotheropods became extinct during the early Jurassic period except for Averostra.

Orionides

Orionides is a clade of tetanuran theropod dinosaurs from the Middle Jurassic to the Present. The clade includes most theropod dinosaurs, including birds.

Orodrominae

Orodrominae is a subfamily of parksosaurid dinosaurs from the Cretaceous of North America and Asia.

Tambatitanis

Tambatitanis is an extinct genus of titanosauriform dinosaur from the Early Cretaceous (probably early Albian) of Japan. It is known from a single type species, Tambatitanis amicitiae. It was probably around 14 meters long and its mass was estimated at some 4 tonnes. It was a basal titanosauriform and possibly belonged to the Euhelopodidae.

Tengrisaurus

Tengrisaurus (meaning "Tengri lizard") is a genus of lithostrotian sauropod, from the Early Cretaceous (Barremian-Aptian), of the Murtoi Formation, Russia. It was described in 2017 by Averianov & Skutschas. The type species is T. starkovi.

Xixiposaurus

Xixiposaurus is a genus of prosauropod dinosaur which existed in what is now Lower Lufeng Formation, China during the lower Jurassic period. It was first named by Sekiya Toru in 2010 and the type species is Xixiposaurus suni.

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