Khunnuchelys

Last updated

Khunnuchelys
Temporal range: Turonian-Campanian, 91–75  Ma
Khunnuchelys lophorhothon holotype skull.png
Holotype skull of Khunnuchelys lophorhothon
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Trionychia
Family: Trionychidae
Subfamily: Trionychinae
Genus: Khunnuchelys
Brinkman et al., 1993
Type species
Khunnuchelys erinhotensis
Brinkman et al., 1993
Species
  • K. erinhotensisBrinkman et al., 1993
  • K. kizylkumensisBrinkman et al., 1993
  • K. lophorhothonDanilov et al., 2013
Synonyms
Synonyms of K. kizulkumensis [1]
Synonyms of K. lophorhothon [2]
  • Trionychidae indet. Kordikova, 1994
  • cf. Lophorhothon sp. Nessov, 1995
  • Khunnuchelys sp. Nessov, 1997
  • Khunnuchelys sp. 1 Danilov and Vitek, 2012
  • Khunnuchelys sp. 2 Danilov and Vitek, 2012

Khunnuchelys was a genus of trionychine turtle from the Late Cretaceous of Asia. Three species are known, K. erinhotensis, the type species, K. kizylkumensis, and K. lophorhothon. K. erinhotensis is known from the Iren Dabasu Formation in China from the late Turonian until the middle Campanian. K. kizylkumensis is known from the late Turonian Bissekty Formation of Uzbekistan. The third species, described in 2013 by Danilov et al., is known from the early to middle Campanian aged Bostobe Formation of Kazakhstan.

Contents

History of naming

K. lophorothon is known from two skulls, and has a complex history of classifications. Originally, it was assigned to the dinosaur genus cf. Lophorhothon by Lev Alexandrovitch Nessov in 1995 as an unidentified species. Later, it was correctly transferred to the genus Khunnuchelys by Danilov and Vitek (2012), but was not described in any detail. The two skulls were named Khunnuchelys sp. 1 and Khunnuchelys sp. 2. by them. The finder of the second skull was Mikhail E. Voskoboynikov, who allowed it to be studied by Lev I. Khosatzky. [2]

K. lophorothon emends the original classification of the species, as the species name if derived from the name of Lophorhothon, the dinosaur it was originally classified under. [2]

Description

Skull

Skull ZIN PH 1/146, one of two skulls assigned to K. lophorhothon Khunnuchelys lophorhothon skull.png
Skull ZIN PH 1/146, one of two skulls assigned to K. lophorhothon

Khunnuchelys is an extinct turtle is which many skulls are known from. In fact, is the only skull-based trionychid from the Cretaceous. [2] The side of the maxillary makes up a beak-like structure, an unusual feature of trionychids. [1] One skull, ZIN PH 1/146, is relatively small, and is only partly preserved. The maxilla and prefrontals of the specimen are only partly known, although the jugals, basioccipitals, supraoccipital crest, and left quadrate are close to complete. The preserved skull length is 9 cm (3.5 in), and the total approximate skull is 17 cm (6.7 in) long. The specimen is unique among Khunnuchelys, as the ventral edge is generally well-preserved. The ventral edge shows that the skull of Khunnuchelys is arched from the front to the back. [2]

Distinguishing characteristics

A set of features unique among trionychids were identified by Brinkman et al. in 1993 during the description of Khunnuchelys erinhotensis and K. kisylkumensis. They are listed below: [2]

The characteristics would not be useful if Khunnuchelys was not a trionychid, but Brinkman et al. found that a classification as a trionychid was likely because of the features listed below: [2]

K. lophorothon is distinguished from the other species by the features listed below, found by Danilov et al. in its description: [2]

Both species can be differentiated from K. erinhotensis: [2]

Classification

Khunnuchelys is a turtle that is grouped within Trionychinae, a subfamily of Trionychidae. The species "Trionyx" kansaiensis is known from shell fragments, that are from the same region of Kazakhstan as K. lophorothon, and might be from the later, in which case, "T." kansaiensis might be synonymous with K. lophorothon. Brinkman et al. found that Khunnuchelys was closely related to Conchochelys, but even though it is likely, Danilov et al. did not find any features to prove their close relationship. [2]

Related Research Articles

<span class="mw-page-title-main">Maxilla</span> Upper jaw bone

The maxilla in vertebrates is the upper fixed 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. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible, which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw.

<span class="mw-page-title-main">Palatine bone</span> Bone of the facial skeleton

In anatomy, the palatine bones are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxillae, they comprise the hard palate.

<i>Aralosaurus</i> Extinct genus of dinosaurs

Aralosaurus was a genus of hadrosaurid dinosaur that lived during the Late Cretaceous in what is now Kazakhstan. It is known only by a posterior half of a skull and some post-cranial bones found in the Bostobe Formation in rocks dated from the Upper Santonian-Lower Campanian boundary, at about 83.6 Ma. Only one species is known, Aralosaurus tuberiferus, described by Anatoly Konstantinovich Rozhdestvensky in 1968. The genus name means Aral Sea lizard, because it was found to the northeast of the Aral Sea. The specific epithet tuberiferus means bearing a tuber because the posterior part of the nasal bone rises sharply in front of the orbits like an outgrowth. Aralosaurus was originally reconstituted with a nasal arch similar to that of North American Kritosaurus. For many years, Aralosaurus was thus placed in the clade of the Hadrosaurinae. This classification was invalidated in 2004, following the re-examination of the skull of the animal which allowed to identify in Aralosaurus many typical characters of Lambeosaurinae. In particular, this study revealed that Aralosaurus had a hollow bony structure located far in front of the orbits, which communicated with the respiratory tract. This structure being broken at its base, its shape and size remains undetermined. More recently, Aralosaurus has been identified as the most basal Lambeosaurinae, and placed with its close relative Canardia from the upper Maastrichtian of France in the new clade of Aralosaurini.

<i>Nodocephalosaurus</i> Extinct genus of dinosaurs

Nodocephalosaurus is a monospecific genus of ankylosaurid dinosaur from New Mexico that lived during the Late Cretaceous in what is now the De-na-zin member of the Kirtland Formation. The type and only species, Nodocephalosaurus kirtlandensis, is known only from a partial skull. It was named in 1999 by Robert M. Sullivan. Nodocephalosaurus has an estimated length of 4.5 metres and weight of 1.5 tonnes. It is closely related and shares similar cranial anatomy to Akainacephalus.

<span class="mw-page-title-main">Palatine process of maxilla</span> Thick, horizontal process of the maxilla

In human anatomy of the mouth, the palatine process of maxilla, is a thick, horizontal process of the maxilla. It forms the anterior three quarters of the hard palate, the horizontal plate of the palatine bone making up the rest.

<span class="mw-page-title-main">Greater palatine canal</span> Passage in the skull that transmits the descending palatine artery and vein

The greater palatine canal is a passage in the skull that transmits the descending palatine artery, vein, and greater and lesser palatine nerves between the pterygopalatine fossa and the oral cavity.

<i>Chimaerasuchus</i> Extinct genus of reptiles

Chimaerasuchus is an extinct genus of Chinese crocodyliform from the Early Cretaceous Wulong Formation. The four teeth in the very tip of its short snout gave it a "bucktoothed" appearance. Due its multicusped teeth and marked heterodonty, it is believed to have been an herbivore. Chimaerasuchus was originally discovered in the 1960s but not identified as a crocodyliform until 1995, instead thought to possibly be a multituberculate mammal. It is highly unusual, as only two other crocodyliforms have displayed any characteristics resembling its adaptations to herbivory.

<i>Anatosuchus</i> Extinct genus of reptiles

Anatosuchus is an extinct genus of notosuchian crocodylomorph discovered in Gadoufaoua, Niger, and described by a team of palaeontologists led by the American Paul Sereno in 2003, in the Journal of Vertebrate Paleontology. Its duck-like snout coincidentally makes it resemble a crocoduck, an imagined hybrid animal with the head of a crocodile and the body of a duck.

<i>Labidosaurikos</i> Extinct genus of reptiles

Labidosaurikos is a genus of extinct captorhinid anapsid reptile that lived around 279 to 272 million years ago during Kungurian age of the lower Permian. The American paleontologist John Willis Stovall first described Labidosaurikos in 1950, naming it "Labidosaurus like" for the striking similarity of the holotype skull of his specimen to the cranial anatomy of another captorhinid Labidosaurus hamatus. Labidosaurus or generally called "lipped lizard" is another genus of the family Captorhinidae whose name is derived from the Greek for "forceps lizard" based on τσιμπίδα and σαυρος ("lizard")

<i>Shaochilong</i> Extinct genus of dinosaurs

Shaochilong is an extinct genus of carcharodontosaurid dinosaur from the mid-Cretaceous Ulansuhai Formation of China. The type species, S. maortuensis, was originally named Chilantaisaurus maortuensis, but was re-described and reclassified in 2009. It was one of the last known carcharodontosaurids to walk the earth. Alongside Mapusaurus from Argentina, they were the only members of the family to live until the end of the Turonian epoch.

<i>Polonosuchus</i> Extinct genus of reptiles

Polonosuchus is a genus of rauisuchid known from the late Triassic of Poland. It was a huge predator about 5–6 metres in length and, like all rauisuchians, was equipped with a large head of long sharp teeth. The legs were placed almost underneath the body, unlike most reptiles, which would have made it quite fast and a powerful runner. The appearance was very similar to that of the more known Postosuchus, of North America, and shared with the latter the ecological niche of the apex predator.

<span class="mw-page-title-main">Trionychinae</span> Subfamily of turtles

The Trionychinae are a subfamily of turtles in the family Trionychidae.

<i>Trionyx</i> Genus of turtles

Trionyx is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today T. triunguis, the African or Nile softshell turtle, is the only extant softshell still classified as Trionyx. The other species still assigned to this genus are only known from fossils. T. triunguis is a relatively large, aquatic piscivore.

Gilmoremys is an extinct genus of softshell turtle which lived during the late Cretaceous of North Dakota, Montana and Wyoming, United States.

Huskerpeton is an extinct genus of recumbirostran from the Early Permian period. They belong to the order Microsauria, which was established in 1863 by Dawson, and was quickly expanded to include many different small taxa. They lived in what is now Nebraska and Kansas. The holotype of Huskerpeton was uncovered at the Eskridge formation in Nebraska, which is part of how it got its name.

<i>Europelta</i> Extinct genus of dinosaurs

Europelta is a monospecific genus of nodosaurid dinosaur from Spain that lived during the Early Cretaceous in what is now the lower Escucha Formation of the Teruel Province. The type and only species, Europelta carbonensis, is known from two associated partial skeletons, and represents the most complete ankylosaur known from Europe. Europelta was named in 2013 by James I. Kirkland and colleagues. Europelta has an estimated length of 5 metres and weight of 1.3 tonnes, making it the largest member of the clade Struthiosaurini.

This glossary explains technical terms commonly employed in the description of dinosaur body fossils. Besides dinosaur-specific terms, it covers terms with wider usage, when these are of central importance in the study of dinosaurs or when their discussion in the context of dinosaurs is beneficial. The glossary does not cover ichnological and bone histological terms, nor does it cover measurements.

<i>Basilemys</i> Extinct genus of turtles

Basilemys is a large, terrestrial trionychoid turtle from the Upper Cretaceous. In Greek, the word "Basil" means royal or kingly and the word "Emys" means turtle. Therefore, Basilemys means King Turtle. Basilemys has been found in rocks dating to the Campanian and Maastrichtian subdivisions of the Late Cretaceous and is considered to be the largest terrestrial turtle of its time. Basilemys has solely been found in North America. The family Nanhsiungchelyidae, which is the family Basilemys belongs to, made its first appearance in the Lower Cretaceous, in what we now call Asia. Because of Basilemys, we know that this family appeared in North America in the Upper Cretaceous. It is possible that Basilemys and other nanhsiungchelyids are immigrants from Asia. They might have arrived in North America by passing through what we now call the Bering Strait somewhere during the Cretaceous. In an analysis made by Sukhanov et al. on a new Nansiunghelyid turtle from the Upper Cretaceous of Mongolia, it was demonstrated that Asian nanhsiungchelyids gave rise to the North American nanhsiungchelyids. Basilemys shares some traits with another member of nanhsiungchelyidae, Zangerlia, which is similar to Basilemys in, for example, skull proportions. However, Basilemys has a more complex triturating surface that includes well-defined pockets on the dentary, and it also has tooth-like projections on the triturating surface of the maxilla.

Allodelphinidae is a family of primitive platanistoid river dolphins found in marine deposits in the eastern North Pacific region, Alaska, and Japan.

<i>Kyhytysuka</i> Extinct marine reptile

Kyhytysuka is an extinct genus of ophthalmosaurian ichthyosaur from Early Cretaceous Colombia. The animal was previously assigned to the genus Platypterygius, but given its own genus in 2021. Kyhytysuka was a mid-sized ophthalmosaurian with heterodont dentition and several adaptations suggesting that it was a macropredatory vertebrate hunter living in shallow waters. It contains a single species, Kyhytysuka sachicarum.

References

  1. 1 2 Vitek, N.A.; Danilov, I.G. (2013). "Soft-shelled turtles (Trionychidae) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan: Skull-based taxa and probable skull-shell associations" (PDF). Cretaceous Research. 43 (2013): 48–58. doi:10.1016/j.cretres.2013.02.009. hdl: 2152/41078 . S2CID   128940175. Archived from the original (PDF) on 2021-08-31. Retrieved 2014-02-24.
  2. 1 2 3 4 5 6 7 8 9 10 Danilov, I.G.; Vitek, N.S.; Averianov, A.O.; Glinskiy, V.N. (2013). "A new softshelled trionychid turtle of the genus Khunnuchelys from the Upper Cretaceous Bostobe Formation of Kazakhstan" (PDF). Acta Palaeontologica Polonica. doi: 10.4202/app.2013.0045 . Archived from the original (PDF) on 2014-02-28.