Nqwebasaurus

{{speciesbox

| fossil_range = Early Cretaceous, {{fossilrange|140|earliest=145.5|latest=136.4}}

| image = Nqwebasaurus.png

| image_caption = Life restoration

| display_parents = 2

| genus = Nqwebasaurus

| parent_authority = de Klerk et al. 2000

| species = thwazi

| authority = de Klerk et al. 2000

}}

Nqwebasaurus is a basal coelurosaur and the basal-most member of the coelurosaurian clade Ornithomimosauria from the Early Cretaceous of South Africa.{{Cite journal|last1=Choiniere|first1=Jonah|last2=Forster|first2=Catherine|last3=De Klerk|first3=William|date=2012-08-01|title=New information on Nqwebasaurus thwazi, a coelurosaurian theropod from the Early Cretaceous Kirkwood Formation in South Africa|url=https://www.researchgate.net/publication/257588809|journal=Journal of African Earth Sciences|volume=s 71–72|pages=1–17|doi=10.1016/j.jafrearsci.2012.05.005|bibcode=2012JAfES..71....1C }} The name Nqwebasaurus is derived from the Xhosa word Nqweba which is the local name for the Kirkwood district, and thwazi is ancient Xhosa for "fast runner".{{Cite news|url=https://www.news24.com/xArchive/Archive/At-last-a-Xhosaurus-20000926|title=At last, a Xhosaurus|work=News24|access-date=2018-04-25|language=en}} Currently it is the oldest coelurosaur in Africa and shows that basal coelurosaurian dinosaurs inhabited Gondwana 50 million years earlier than previously thought. The type specimen of Nqwebasaurus was discovered by William J. de Klerk who is affiliated with the Albany Museum in Grahamstown. It is the only fossil of its species found to date and was found in the Kirkwood Formation of the Uitenhage Group. Nqwebasaurus has the unofficial nickname "Kirky", due to being found in the Kirkwood.{{Cite journal|last1=De Klerk|first1=William|last2=Forster|first2=Catherine|last3=Sampson|first3=Scott|last4=Chinsamy-Turan|first4=Anusuya|last5=Ross|first5=Callum|date=2000-06-27|title=A new coelurosaurian dinosaur from the Early Cretaceous of South Africa|url=https://www.researchgate.net/publication/233184192|journal=Journal of Vertebrate Paleontology|volume=20|issue=2 |pages=324–332|doi=10.1671/0272-4634(2000)020[0324:ANCDFT]2.0.CO;2}}{{Cite journal|last1=Forster|first1=Catherine|last2=A. Farke|first2=Andrew|last3=A. Mccartney|first3=Jacob|last4=De Klerk|first4=William|last5=Ross|first5=Callum|date=2009-03-30|title=A "Basal" Tetanuran from the Lower Cretaceous Kirkwood Formation of South Africa|url=https://www.researchgate.net/publication/232667794|journal=Journal of Vertebrate Paleontology|volume=29|issue=1 |pages=283–285|doi=10.1671/039.029.0101|bibcode=2009JVPal..29..283F }}

History of discovery

Nqwebasaurus was first discovered by William J. de Klerk and Callum Ross in July 1996 during a joint expedition led by the Albany Museum in Grahamstown and Stony Brook in New York, United States, where Callum Ross was affiliated at the time. The fossil is remarkably complete and is considered an extremely rare find as no coelurosaur fossils had previously been found in Africa at this time. No new Nqwebasaurus fossils have been discovered since.

Description

File:Nqwebasaurus Scale.svg

Nqwebasaurus is considered to have been a small to medium-sized coelurosaur. The type specimen is approximately 30 cm (1 ft) high and is estimated to have been 90 cm (3 ft) long, although its complete length is not known due to the caudal vertebrae of the type specimen being incomplete. Gregory S. Paul estimated its adult size at {{cvt|1|m|ft}} in length and {{cvt|1|kg|lbs}} in body mass.{{Cite book|last=Paul|first=Gregory S.|url=http://worldcat.org/oclc/985402380|title=The Princeton Field Guide to Dinosaurs|year=2016|publisher=Princeton University Press|isbn=978-1-78684-190-2|oclc=985402380|pages=128}} In addition the type specimen is thought to be a late juvenile, although with the type specimen being the only fossil representing its species it is currently not possible to compare the fossil with another member of its species.

Nqwebasaurus has a long, three-fingered hand which includes a partially opposable thumb with a recurved claw. The claws on its hands differ in shape where the claws of the first and second digits are recurved and the third claw is not. This trait is unusual in theropod dinosaurs, however, it has been observed in some ornithomimosaurs such as Struthiomimus. Nqwebasaurus also lacks serrations on its maxillary teeth, has a reduced dentition, and contains gastroliths in its abdominal cavity. Again this is unusual trait for carnivorous theropod dinosaurs as gastroliths are more commonly found in herbivorous vertebrates and modern ostriches. Due to these morphological traits, Nqwebasaurus is thought to have been an omnivore.

As more basal theropod species, especially those on the evolutionary line to birds, had feathers it is accepted that Nqwebasaurus was likely at least partially feathered or had a feather coat for thermoregulation.

Classification

The most recent phylogenetic analyses that include Nqwebasaurus recovered it in the position as the basalmost member of Ornithomimosauria. However, many older studies have recovered different positions for the taxon amongst Coelurosauria, ranging from a basal member of the group, a compsognathid, or an alvarezsaurid. In combination with the rather divergent anatomy of Nqwebasaurus in comparison to other ornithomimosaurs, it is potentially uncertain what the taxon's phylogenetic affinities may be.{{cite journal |first1=M.A. |last1=Cerroni |first2=F.L. |last2=Agnolin |first3=F. |last3=Brissón Egli |first4=F.E. |last4=Novas |year=2019 |title=The phylogenetic position of Afromimus tenerensis Sereno, 2017 and its paleobiogeographical implications |journal=Journal of African Earth Sciences |volume=159 |pages=103572 |doi=10.1016/j.jafrearsci.2019.103572|bibcode=2019JAfES.15903572C |s2cid=201352476 }}

The cladogram below follows an analysis by Yuong-Nam Lee, Rinchen Barsbold, Philip J. Currie, Yoshitsugu Kobayashi, Hang-Jae Lee, Pascal Godefroit, François Escuillié & Tsogtbaatar Chinzorig. The analysis was published in 2014, and displays the current phylogenetic position of Nqwebasaurus.{{cite journal|last1=Lee|first1=Y.-N.|last2=Barsbold|first2=R.|last3=Currie|first3=P.J.|last4=Kobayashi|first4=Y.|last5=Lee|first5=H.-J.|last6=Godefroit|first6=P.|last7=Escuillié|first7=F.|last8=Chinzorig|first8=T.|year=2014|title=Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus|url=https://www.academia.edu/11176967|journal=Nature|volume=515|issue=7526 |pages=1–4|doi=10.1038/nature13874|pmid=25337880|bibcode=2014Natur.515..257L }}

{{clade| style=font-size:100%;line-height:80%

|label1=Coelurosauria

|1={{clade

|1=Zuolong 80px

|2={{clade

|1=Tanycolagreus 80px

|label2=Tyrannoraptora

|2={{clade

|1=Proceratosaurus

|2=Tyrannosauroidea 80 px

|3={{clade

|1=Ornitholestes 80px