''Haopterus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

pterodactyloid Pterodactyloidea (derived from the Greek words ''πτερόν'' (''pterón'', for usual ''ptéryx'') "wing", and ''δάκτυλος'' (''dáktylos'') "finger" meaning "winged finger", "wing-finger" or "finger-wing") is one of the two traditional ...

pterosaur Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 ...

from the

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is precede ...

- Aptian-age

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eig ...

Yixian Formation The Yixian Formation (; formerly transcribed as Yihsien Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its exq ...

of Liaoning, China. Its fossil remains dated back 124.6 million years ago.

Discovery and naming

It was in 2001 named by

Wang Xiaolin Wang may refer to: Names * Wang (surname) (王), a common Chinese surname * Wāng (汪), a less common Chinese surname * Titles in Chinese nobility * A title in Korean nobility * A title in Mongolian nobility Places * Wang River in Thailand ...

and

Lü Junchang Lü Junchang (; 1965 – 9 October 2018) was a Chinese palaeontologist and professor at the Institute of Geology, Chinese Academy of Geological Sciences. An expert on Mesozoic reptiles, he described and named dozens of dinosaur and pterosaur taxa ...

. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

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 Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

, refers to the condition of the

metatarsals The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the me ...

. The genus is based on

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

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 A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles can look very different from the adult form, particularly in colour, and may not fill the same niche as the adult form. In many o ...

, including a skull, lower jaws,

pectoral girdle The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists of ...

sternum The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sha ...

, wings,

cervical In anatomy, cervical is an adjective that has two meanings: # of or pertaining to any neck. # of or pertaining to the female cervix: i.e., the ''neck'' of the uterus. *Commonly used medical phrases involving the neck are **cervical collar **cerv ...

and

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

e, partial pelvis and metatarsals.

Description

Lingual muscles of Haopterus and Liaoxipterus

The skull of ''Haopterus'' is with a length of long and low, lacking a crest. The snout is pointed but rounded. The

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

and

praemaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

are completely fused with no visible suture. The nasopraeorbital skull opening is elongated and elliptical with a length of , 27,6 percent of the total skull length. The lower jaws have a length of . 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 A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, t ...

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 . The sternum was fan-shaped with a prominent keel. The wings are robustly built; the

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

is with longer than the wing metacarpal which has a length of . The

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the other wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingspan o ...

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 .

Phylogeny

''Haopterus'' was by Wang classified as a member of the

Pterodactylidae Pterodactylidae is a controversial group of pterosaurs. During the 2000s and 2010s, several competing definitions for the various Jurassic pterodactyloid groups were proposed. Pereda-Suberbiola ''et al.'' (2012) used Fabien Knoll's (2000) defini ...

, mainly because of the combination of robust teeth with the lack of a skull crest. In 2006 however, a

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analysis by Lü showed it was a basal member of the

Ornithocheiroidea Ornithocheiroidea (or ornithocheiroids) is a group of pterosaurs within the extinct suborder Pterodactyloidea. They were typically large pterosaurs that lived from the Early to Late Cretaceous periods (Valanginian to Maastrichtian stages), with fo ...

''sensu'' Unwin (2003). Later, an analysis by Kellner ''et al.'', 2019 showed ''Haopterus'' to be a close relative of ''

Mimodactylus ''Mimodactylus'' is a genus of mimodactylid pterodactyloid pterosaur from the Late Cretaceous of what is now Lebanon. Discovery and naming In the ''Lagerstätte'' of Hjoula, ten kilometres inland from the port of Byblos, commercial fossil h ...

''. Together they form the family Mimodactylidae, which is the sister group to the

Istiodactylidae Istiodactylidae is a small family of pterosaurs. This family was named in 2001 after the type genus ''Istiodactylus'' was discovered not to be a member of the genus '' Ornithodesmus''. Systematics and distribution Remains of taxa that can be ...

. The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

below follows Witton's 2012 analysis: The cladogram below is a topology recovered by Kellner ''et al.'' (2019). In the analyses, they recovered ''Haopterus'' as the sister taxon of ''

'' within the family Mimodactylidae, and placed within the more inclusive group Istiodactyliformes.

Paleobiology

The authors concluded that its slender hindfeet meant that it was forced to move

quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...

ally on land, suggesting a

piscivore A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evoluti ...

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 ''

'' was considered to be a faunivore feeding on crustaceans, suggested by Kellner ''et al.'', 2019.

References

External links