Uktenadactylus
Encyclopedia
Uktenadactylus is a genus
of pterodactyloid
pterosaur from the Lower Cretaceous Paw Paw Formation
of Texas
.
In 1994 Yuong Nam-Lee named a new species within the genus Coloborhynchus
: Coloborhynchus wadleighi, based on a partial snout found in 1992 in Albian
layers in Tarrant County, holotype
SMU 73058 (Shuler Museum of Paleontology, Southern Methodist University
at Dallas). The specific name honours the collector of the fossil, Chris Wadleigh. The reference of the species to the genus Coloborhynchus was based on the fact that both C. wadleighi and the type species
of Coloborhynchus, Coloborhynchus clavirostris, share the trait of having three pairs of teeth laterally placed within a broad snout tip. This would distinguish both from the species Criorhynchus simus and justify a revival of the genus Coloborhynchus that since an analysis by Reginald Walter Hooley in 1914 had generally been considered identical to the genus Criorhynchus or the genus the latter had again been sunk into, Ornithocheirus
.
As a result of the reappearance of the concept European workers referred many species discovered in South-America to Coloborhynchus, a practice rejected by most South-American researchers. In 2009 a study by the Brazilan paleontologists Taissa Rodrigues and Alexander Kellner
concluded that Coloborhynchus comprised only a single species, its type species C. clavirostris. Accordingly, in the same publication they created a new genus for C. wadleighi: Uktenadactylus. The genus name is derived from Uktena, a giant horned snake from the mythology
of the Cherokee
and Greek daktylos, "finger", a common element in the names of pterosaurs since Pterodactylus
, referring to their typical wing finger.
The fossil has a length of about fifteen centimetres and consists of the front end of the skull, containing the premaxilla
and a small part of the maxilla
. On top the base of a crest is present, gradually curving upwards and ending at a height of 7.5 centimetres, having attained at that point a thickness of four millimetres. The snout broadens towards the front. On the left side eight tooth sockets or alveoli are visible, on the right side six. The first pair of teeth was located in the flat tip of the snout, pointing forwards. The alveoli at first increase in size from the tip towards the back, the third pair being the largest with a diameter of 17.6/17.7 millimetres. The fourth pair is much smaller; to the back gradually the tooth sockets again increase in size. Thus a "prey grab" is formed. According to Rodrigues and Kellner the species has two unique traits: the presence of an oval depression above and in between the first pair of teeth and of a ventral medial depression between the second pair of teeth, a circular hollow positioned on the lower edge of the snout tip that Lee had interpreted as a possible pneumatic foramen.
Rodrigues and Kellner base the distinction between Uktenadactylus and Coloborhynchus clavirostris on several stratigraphical, methodological and phylogenetic considerations. There is a possible age difference of perhaps over thirty million years between the Berriasian
-Valanginian
British and the younger Albian
-Cenomanian
American form. Because both taxa are based on very limited remains, that however, even within these limits are clearly distinguishable on the species level, they reject a rash assumption of generic identity. Also the uncertain affinity with the closely related form Siroccopteryx would make such an assumption problematical. Rodrigues and Kellner identify only one shared derived trait for Uktenadactylus and Coloborhynchus clavirostris: an extreme enlargement of the second and third pairs of teeth. Differences between the taxa include the more forward position of the crest with C. clavirostris, beginning at the very tip of the snout; a deeper palatal groove and shallow grooves running parallel to the ridge of the front part of the palate; a depression located below the first alveoli and a more lateral position of the second, third and forth tooth pairs whereas the fifth and sixth pair are to the contrary much closer to the midline of the skull. Both forms share some derived traits with Siroccopteryx: the second and third teeth pairs are larger than the fourth; the tip of the snout is flat causing the "prey grab" to be rectangular in cross-section and a similar thickness of the crest. The authors conclude from this that the three taxa likely formed an, as yet unnamed, clade
together within the Anhangueridae.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of pterodactyloid
Pterodactyloidea
Pterodactyloidea forms one of the two suborders of pterosaurs , and contains the most derived members of this group of flying reptiles...
pterosaur from the Lower Cretaceous Paw Paw Formation
Paw Paw Formation
The Paw Paw Formation is a geological formation in Texas whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-Vertebrate paleofauna:* Pawpawsaurus campbelli - "Skull."...
of Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
.
In 1994 Yuong Nam-Lee named a new species within the genus Coloborhynchus
Coloborhynchus
Coloborhynchus is a genus in the pterosaur family Ornithocheiridae, and is known from the Lower Cretaceous of England , and possibly the Aptian age of Brazil and Texas, depending on which species are included.-Description:The type specimen of Coloborhynchus is known only from a partial upper jaw...
: Coloborhynchus wadleighi, based on a partial snout found in 1992 in Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...
layers in Tarrant County, holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
SMU 73058 (Shuler Museum of Paleontology, Southern Methodist University
Southern Methodist University
Southern Methodist University is a private university in Dallas, Texas, United States. Founded in 1911 by the Methodist Episcopal Church, South, SMU operates campuses in Dallas, Plano, and Taos, New Mexico. SMU is owned by the South Central Jurisdiction of the United Methodist Church...
at Dallas). The specific name honours the collector of the fossil, Chris Wadleigh. The reference of the species to the genus Coloborhynchus was based on the fact that both C. wadleighi and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of Coloborhynchus, Coloborhynchus clavirostris, share the trait of having three pairs of teeth laterally placed within a broad snout tip. This would distinguish both from the species Criorhynchus simus and justify a revival of the genus Coloborhynchus that since an analysis by Reginald Walter Hooley in 1914 had generally been considered identical to the genus Criorhynchus or the genus the latter had again been sunk into, Ornithocheirus
Ornithocheirus
Ornithocheirus was a pterosaur from the Cretaceous period of Europe and South America...
.
As a result of the reappearance of the concept European workers referred many species discovered in South-America to Coloborhynchus, a practice rejected by most South-American researchers. In 2009 a study by the Brazilan paleontologists Taissa Rodrigues and Alexander Kellner
Alexander Kellner
Alexander Wilhelm Armin Kellner is a Liechtensteinian/Brazilian paleontologist, a leading expert in the field of the study of pterosaurs....
concluded that Coloborhynchus comprised only a single species, its type species C. clavirostris. Accordingly, in the same publication they created a new genus for C. wadleighi: Uktenadactylus. The genus name is derived from Uktena, a giant horned snake from the mythology
Mythology
The term mythology can refer either to the study of myths, or to a body or collection of myths. As examples, comparative mythology is the study of connections between myths from different cultures, whereas Greek mythology is the body of myths from ancient Greece...
of the Cherokee
Cherokee
The Cherokee are a Native American people historically settled in the Southeastern United States . Linguistically, they are part of the Iroquoian language family...
and Greek daktylos, "finger", a common element in the names of pterosaurs since Pterodactylus
Pterodactylus
Pterodactylus is a genus of pterosaurs, whose members are popularly known as pterodactyls. It was the first to be named and identified as a flying reptile...
, referring to their typical wing finger.
The fossil has a length of about fifteen centimetres and consists of the front end of the skull, containing the premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
and a small part of the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
. On top the base of a crest is present, gradually curving upwards and ending at a height of 7.5 centimetres, having attained at that point a thickness of four millimetres. The snout broadens towards the front. On the left side eight tooth sockets or alveoli are visible, on the right side six. The first pair of teeth was located in the flat tip of the snout, pointing forwards. The alveoli at first increase in size from the tip towards the back, the third pair being the largest with a diameter of 17.6/17.7 millimetres. The fourth pair is much smaller; to the back gradually the tooth sockets again increase in size. Thus a "prey grab" is formed. According to Rodrigues and Kellner the species has two unique traits: the presence of an oval depression above and in between the first pair of teeth and of a ventral medial depression between the second pair of teeth, a circular hollow positioned on the lower edge of the snout tip that Lee had interpreted as a possible pneumatic foramen.
Rodrigues and Kellner base the distinction between Uktenadactylus and Coloborhynchus clavirostris on several stratigraphical, methodological and phylogenetic considerations. There is a possible age difference of perhaps over thirty million years between the Berriasian
Berriasian
In the geological timescale, the Berriasian is an age or stage of the Early or Lower Creteceous. It is the oldest or lowest subdivision in the entire Cretaceous. It spanned between 145.5 ± 4.0 Ma and 140.2 ± 3.0 Ma...
-Valanginian
Valanginian
In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 140.2 ± 3.0 Ma and 136.4 ± 2.0 Ma...
British and the younger Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...
-Cenomanian
Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...
American form. Because both taxa are based on very limited remains, that however, even within these limits are clearly distinguishable on the species level, they reject a rash assumption of generic identity. Also the uncertain affinity with the closely related form Siroccopteryx would make such an assumption problematical. Rodrigues and Kellner identify only one shared derived trait for Uktenadactylus and Coloborhynchus clavirostris: an extreme enlargement of the second and third pairs of teeth. Differences between the taxa include the more forward position of the crest with C. clavirostris, beginning at the very tip of the snout; a deeper palatal groove and shallow grooves running parallel to the ridge of the front part of the palate; a depression located below the first alveoli and a more lateral position of the second, third and forth tooth pairs whereas the fifth and sixth pair are to the contrary much closer to the midline of the skull. Both forms share some derived traits with Siroccopteryx: the second and third teeth pairs are larger than the fourth; the tip of the snout is flat causing the "prey grab" to be rectangular in cross-section and a similar thickness of the crest. The authors conclude from this that the three taxa likely formed an, as yet unnamed, clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
together within the Anhangueridae.