''Pterofiltrus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

ctenochasmatid Ctenochasmatidae is a group of pterosaurs within the suborder Pterodactyloidea. They are characterized by their distinctive teeth, which are thought to have been used for filter-feeding. Ctenochasmatids lived from the Late Jurassic to the Early ...

pterosaur Pterosaurs are 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 million to 66 million years ago). Pterosaurs are the earli ...

from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

of western

Liaoning ) , image_skyline = , image_alt = , image_caption = Clockwise: Mukden Palace in Shenyang, Xinghai Square in Dalian, Dalian coast, Yalu River at Dandong , image_map = Liaoning in China (+all claims hatched).svg , ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Discovery and naming

''Pterofiltrus'' was named by Jiang Shunxing and Wang Xiaolin in

2011 The year marked the start of a Arab Spring, series of protests and revolutions throughout the Arab world advocating for democracy, reform, and economic recovery, later leading to the depositions of world leaders in Tunisia, Egypt, and Yemen ...

. The

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

is ''Pterofiltrus qiui''. The generic name is derived from Greek πτερόν, ''pteron'', "wing", and a Mediaeval

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''filtrum'', "felt" or "filter", in reference to the

dentition Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

honours Professor Qiu Zhanxiang. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of ''Pterofiltrus'', IVPP V12339, was early 21st century discovered at Zhangjiagou in

Liaoning Province ) , image_skyline = , image_alt = , image_caption = Clockwise: Mukden Palace in Shenyang, Xinghai Square in Dalian, Dalian coast, Yalu River at Dandong , image_map = Liaoning in China (+all claims hatched).svg , ...

in a layer of the Jianshangou Beds of the lower

Yixian Formation The Yixian Formation (; formerly Romanization of Chinese, transcribed as Yihsien Formation or Yixiang Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the Barremian stage of the Early Cretaceous. I ...

dating from the early

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

, about 125 million years old. It consists of a disarticulated skull compressed on a slab together with two rami of a

hyoid The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verte ...

and the first two neck vertebrae.

Description

The skull of ''Pterofiltrus'' is very elongated, with an estimated length of 208 millimetres. It has a smooth, slightly concave, upper profile lacking any bony crests. The lower jaws too are long, and without a keel. The describers established the presence of five diagnostic traits. The total number of teeth in the head is about 112. The teeth cover more than half of the skull length, at 55.8%. The front teeth differ in length. The symphysis of the lower jaws represent more than half of the

mandibula In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone ...

r length, at 58%. The underside of this symphysis features a trough. The last two traits are

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to ...

unique to the species. The dentition consists of very elongated pointed teeth, directed partly sideways. These on average strongly increase in length to the front meanwhile becoming more anteriorly directed. Closing the beak the teeth would have meshed together, with the front teeth sticking out beyond the upper and lower margins of the head. The teeth are evenly spaced. There are twenty-nine teeth in the upper jaw with the second and fifth tooth being the longest. The 174 millimetres long lower jaw contains about twenty-seven teeth.

Phylogeny

The describers assigned ''Pterofiltrus'' to the family

Ctenochasmatidae Ctenochasmatidae is a group of pterosaurs within the suborder Pterodactyloidea. They are characterized by their distinctive teeth, which are thought to have been used for filter-feeding. Ctenochasmatids lived from the Late Jurassic to the Earl ...

within the larger group

Archaeopterodactyloidea Archaeopterodactyloidea (meaning "ancient Pterodactyloidea") is an extinct clade of pterodactyloid pterosaurs that lived from the middle Late Jurassic to the latest Early Cretaceous periods (Kimmeridgian to Albian stages) of Africa, Asia, Europe a ...

, using the comparative method. The cladogram below follows a

phylogenetic analysis In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...

conducted by Lü and colleagues in 2016. They recovered ''Pterofiltrus'' as the sister taxon of ''

Gladocephaloideus ''Gladocephaloideus'' is a genus of ctenochasmatid Ctenochasmatoidea, ctenochasmatoid pterosaur from the Early Cretaceous period (early Aptian stage) of what is now western Liaoning, China. Discovery ''Gladocephaloideus'' is known from a compl ...

'', both within the Ctenochasmatidae.Lü J., Kundrát M., Shen C., 2016, "New Material of the Pterosaur ''Gladocephaloideus'' Lü et al., 2012 from the Early Cretaceous of Liaoning Province, China, with Comments on Its Systematic Position", ''PLoS ONE'' 11(6): e0154888.

References

{{Portal bar, Paleontology, China Early Cretaceous pterosaurs of Asia Ctenochasmatoids Yixian fauna Fossil taxa described in 2011 Pterosaur genera

Discovery and naming

Description

Phylogeny

See also

References