''Pterofiltrus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 (; 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 to ...

from the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

of western

Liaoning Liaoning () is a coastal province in Northeast China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and is the northernmost ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

Discovery and naming

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

2011 File:2011 Events Collage.png, From top left, clockwise: a protester partaking in Occupy Wall Street heralds the beginning of the Occupy movement; protests against Libyan dictator Muammar Gaddafi, who was killed that October; a young man celebrate ...

. 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 specimen ...

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 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 ...

''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-physiolo ...

. The specific name honours Professor Qiu Zhanxiang. The

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 several ...

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

Liaoning Province Liaoning () is a coastal provinces of China, province in Northeast China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and i ...

in a layer of the Jianshangou Beds of the lower

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 ex ...

dating from the early

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

, 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 vertebra. ...

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 anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

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 t ...

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 Early C ...

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 ...

, using the comparative method. The cladogram below follows a

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

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

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

'', 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, Cretaceous, China Early Cretaceous pterosaurs of Asia Ctenochasmatoids Yixian fauna Fossil taxa described in 2011

Discovery and naming

Description

Phylogeny

See also

References