Haopterus

It was in 2001 named by Wang Xiaolin and Lü Junchang. The type species is Haopterus gracilis. The genus name honors Professor Hao Yichun and combines her name with a Latinized Greek pteron, "wing". The specific name, "slender-built" in Latin, refers to the condition of the metatarsals.

The genus is based on holotype IVPP V11726, a crushed fossil found in 1998 at the Sihetun-locality. The layer it was discovered in was argon-dated at an age of 124.6 million years. It was the first Chinese pterosaur fossil preserving the skull. It consists of the front half of a subadult, including a skull, lower jaws, pectoral girdle, sternum, wings, cervical and dorsal vertebrae, partial pelvis and metatarsals.

File:Lingual muscles of Haopterus and Liaoxipterus.png (bottom)]]

File:Haopterus gracilis skull NMNS.jpg]]

The skull of Haopterus is with a length of {{convert|145|mm|in|sp=us}} long and low, lacking a crest. The snout is pointed but rounded. The maxilla and praemaxilla are completely fused with no visible suture. The nasopraeorbital skull opening is elongated and elliptical with a length of {{convert|4|cm|in|sp=us}}, 27,6 percent of the total skull length. The lower jaws have a length of {{convert|128|mm|in|sp=us}}. On the front two thirds of their length teeth are present. There are twelve pairs of teeth in both the upper and the lower jaws. The teeth are robust, sharp, pointed, and curving backwards. To the front they gradually increase in length and point more to the front. The first three pairs in the praemaxilla are very small though; the describers assumed these were replacement teeth, recently erupted.

The back of the skull and the cervical vertebrae are strongly crushed, obscuring most details. Eight dorsal vertebrae are preserved, with a total length of {{convert|52|mm|in|sp=us}}. The sternum was fan-shaped with a prominent keel. The wings are robustly built; the ulna is with {{convert|101|mm|in|sp=us}} longer than the wing metacarpal which has a length of {{convert|89|mm|in|sp=us}}. The wingspan of the type individual was estimated at 1.35 meter (4.43 ft). In comparison, the hindlimbs must have been weakly built, the metatarsal having a length of just {{convert|17|mm|in|sp=us}}.

Haopterus was by Wang classified as a member of the Pterodactylidae, mainly because of the combination of robust teeth with the lack of a skull crest. In 2006 however, a cladistic analysis by Lü showed it was a basal member of the Ornithocheiroidea sensu Unwin (2003).Lü Junchang and Ji Qiang (2006), "Preliminary results of a phylogenetic analysis of the pterosaurs from western Liaoning and surrounding area", Journal of the Paleontological Society of Korea 22 (1): 239–261 Later, an analysis by Kellner et al., 2019 showed Haopterus to be a close relative of Mimodactylus. Together they form the family Mimodactylidae, which is the sister group to the Istiodactylidae.{{Cite journal|last1=Kellner|first1=Alexander W. A.|last2=Caldwell|first2=Michael W.|last3=Holgado|first3=Borja|last4=Vecchia|first4=Fabio M. Dalla|last5=Nohra|first5=Roy|last6=Sayão|first6=Juliana M.|last7=Currie|first7=Philip J.|date=2019-11-29|title=First complete pterosaur from the Afro-Arabian continent: insight into pterodactyloid diversity|journal=Scientific Reports|language=en|volume=9|issue=1|page=17875|doi=10.1038/s41598-019-54042-z|pmid=31784545|pmc=6884559|issn=2045-2322|doi-access=free|bibcode=2019NatSR...917875K }}

The cladogram below follows Witton's 2012 analysis:{{cite journal|doi=10.1371/journal.pone.0033170|pmid=22470442|pmc=3310040|title=New Insights into the Skull of Istiodactylus latidens (Ornithocheiroidea, Pterodactyloidea)|journal=PLOS ONE|volume=7|issue=3|pages=e33170|year=2012|last1=Witton|first1=Mark P.|bibcode=2012PLoSO...733170W|doi-access=free}}

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

|1={{clade

|1=Pterodactylus antiquus

|2={{clade

|1=Pteranodon longiceps

|2=Coloborhynchus spielbergi

|3=Hongshanopterus lacustris

|4=Haopterus gracilis

|label5=Istiodactylidae

|5={{clade

|1=Nurhachius ignaciobritoi

|2=Longchengpterus zhaoi

|3={{clade

|1=Istiodactylus latidens

|2=Istiodactylus sinensis

|3=Liaoxipterus brachyognathus }} }} }} }} }}

File:Teeth comparinson of Mimodactylus and Haopterus.jpg]]

The cladogram below is a topology recovered by Kellner et al. (2019). In the analyses, they recovered Haopterus as the sister taxon of Mimodactylus within the family Mimodactylidae, and placed within the more inclusive group Istiodactyliformes.{{cite journal |last1=Kellner |first1=Alexander W. A. |last2=Caldwell |first2=Michael W. |last3=Holgado |first3=Borja |last4=Vecchia |first4=Fabio M. Dalla |last5=Nohra |first5=Roy |last6=Sayão |first6=Juliana M. |last7=Currie |first7=Philip J. |title=First complete pterosaur from the Afro-Arabian continent: insight into pterodactyloid diversity |journal=Scientific Reports |date=2019 |volume=9 |issue=1 |page=17875 |doi=10.1038/s41598-019-54042-z|doi-access=free |pmid=31784545 |pmc=6884559 |bibcode=2019NatSR...917875K }}

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

| label1=Istiodactyliformes

| 1={{clade

| label1=Mimodactylidae

| 1={{clade

| 1=Haopterus

| 2=Mimodactylus

}}

| 2={{clade

| 1=Hongshanopterus

| label2=Istiodactylidae

| 2={{clade

| 1=Nurhachius

| label2=Istiodactylinae

| 2={{clade

| 1=Istiodactylus

| 2=Liaoxipterus

}}

}}

}}

}}

}}

The authors concluded that its slender hindfeet meant that it was forced to move quadrupedally on land, suggesting a piscivore lifestyle as a specialised soarer.Wang X. and Lü J. (2001). Discovery of a pterodactyloid pterosaur from the Yixian Formation of western Liaoning, China. Chinese Science Bulletin 45(12):447–454. Although its close relative Mimodactylus was considered to be a faunivore feeding on crustaceans, suggested by Kellner et al., 2019.

• List of pterosaur genera
• Timeline of pterosaur research

{{Reflist}}

• [https://web.archive.org/web/20070923153840/http://archosauria.org/pterosauria/taxonomy/genera/haopterus.html Haopterus] in The Pterosauria

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Category:Pteranodontoidea

Category:Early Cretaceous pterosaurs of Asia

Category:Fossil taxa described in 2001

Category:Yixian fauna

Category:Taxa named by Lü Junchang