Clidastes

Last updated

Clidastes
Temporal range: Late Cretaceous, Coniacian-Campanian, 85–70  Ma
Clidastes AMNH FR 192.jpg
Skeleton referred to C. liodontus (AMNH FR 192)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Clade: Mosasauria
Family: Mosasauridae
Subfamily: Mosasaurinae
Genus: Clidastes
Cope, 1868
Type species
Clidastes propython
Cope, 1869
Species
  • C. iguanavusCope, 1868 (former type species)
  • C. propythonCope, 1869

Clidastes is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like Mosasaurus and Prognathodon . Clidastes is known from deposits ranging in age from the Coniacian to the early Campanian in the United States.

Contents

Clidastes means "locked vertebrae", which originates from the Greek noun κλειδί, or kleid meaning key (akin to Latin claudere meaning to shut). This refers to how the vertebral processes allow the proximal heads of the vertebrae to interlock for stability and strength during swimming.

It was one of the earliest hydropedal [note 1] mosasaurs, representing one of the first properly marine predatory forms alongside other early hydropedal genera like Tylosaurus and Platecarpus . [2] It was likely an agile swimmer that preyed upon cephalopods, fish and other small vertebrates in shallow water. Isotopic analysis on teeth specimens has suggested that this genus and Platecarpus may have entered freshwater occasionally, just like modern sea snakes. [3]

Description

Restoration of C. propython. Clidastes proph1DB.jpg
Restoration of C. propython.

Clidastes was the one of the smallest of the mosasaurs (the smallest known being Dallasaurus ), averaging 2–4 meters (6.6–13.1 ft) in length, with the largest specimens reaching 6.2 meters (20 feet) long. [4] The generic name refers to how the vertebral processes allow the proximal heads of the vertebrae to interlock for stability and strength during swimming. Even though the vertebrae lock together, the living animal would have still had a range of motion in the horizontal plane that is sufficient to allow for the high quality of swimming in shallow waters. [5] Additionally the strengthening of the tail, and entire backbone, allowed for muscle attachments to help it swimming. It possessed a delicate and slim form with an expansion of the neural spines and chevrons near the tip of the tail and this enabled it to chase down the fastest of prey.

Illustration of a Clidastes forelimb from The Osteology of the Reptiles by Samuel Wendell Williston (1925). The Osteology of the Reptiles p181 Fig-146.png
Illustration of a Clidastes forelimb from The Osteology of the Reptiles by Samuel Wendell Williston (1925).

Due to being a well-represented and well-studied genus, Russell (1967) [6] could list a large range of unambiguous character states for the genus, including the following: "Premaxilla with or without small rostrum anterior to premaxillary teeth. Fourteen to eighteen teeth in maxilla. Prefrontal forms small portion of posterolateral border of external nares, broad triangular ala projects laterally from supraorbital wing. Prefrontal and postorbitofrontal widely separated above orbits. Lateral margins of frontal nearly straight and converge anteriorly, median dorsal ridge weak. Ventral process of postorbitofrontal to jugal confluent with broadly exposed dorsal surface of postorbitofrontal. No ventroposterior process on jugal. Parietal foramen small, located entirely within parietal. Margins of dorsal parietal surface parallel one another and cranial midline to posterior base of diverging suspensorial rami, forming narrow rectangular field medially on parietal. Squamosal sends abbreviated wing medially to contact ramus irom parietal. Otosphenoidal crest on prootic covers exit for cranial nerve VII laterally. Fourteen to sixteen teeth in pterygoid. Suprastapedial process of quadrate moderately large; tympanic ala very thick. Stapcdial pit elliptical in form. Sixteen-18 teeth in dentary. Small projection of dentary aritcrior to first dentary tooth. Medial wing Irom angular contacts or nearly contacts coronoid. Dorsal. edge of surangular very thin Iamina of bone rising anteriorly to position high on posterior surface of coronoid. Retroarticular process of articular triangular in outline with heavy dorsal crest. Mandibular teeth usually compressed, bicarinatc and with smooth enamel surfaces." Russell noted that his diagnosis was exclusively based on C. propython and C. liodontus and might not necessarily apply to C. sternbergii (later referred to its own genus, Eonatator ) or C. iguanavus. [6]

Teeth and tooth replacement

Clidastes skull from The Osteology of the Reptiles by Samuel Wendell Williston (1925). The Osteology of the Reptiles p67.png
Clidastes skull from The Osteology of the Reptiles by Samuel Wendell Williston (1925).

Mosasaur teeth are of rather uniform morphology (with a few exceptions, such as in Globidens ) with a pointed and curved tooth crown that sits on a pedicel composed of bone. [7] The enamel surface is smooth and the crown is subdivided into a lingual and labial surface while the outer surface of the crown is made of enamel and the inner layer is made of dentine. [7] Fossil specimens show evidence of upright vertically positioned developing replacement teeth. Snakes have been thought of as the only squamates with replacement teeth that develop in a horizontal posteriorly inclined position. Snakes deviate from the usual varanoid pattern of tooth replacement, in that their replacement teeth develop in a horizontal inclined position and rotate, however snakes differ from Mosasaurs because they do not possess the resorption pits found in Mosasaurs. [7]

Mosasaurs, including Clidastes, and snakes both share the traits of thecodont tooth implantation, and a recumbent position of replacement teeth. However mosasaurs develop replacement teeth by rotating within the resorption pits that are at the base of functional teeth. This is different from snakes because snakes have recumbent replacement teeth that lay horizontal and rotate into functional position when needed. In mosasaurs like Clidastes, once the functional tooth is lost, a new tooth pedicel develops for the replacement tooth. In the case of mosasaurs though, they differ from the thecodont dentition pattern of archosaur and mammals because mosasaurs show true ankylosis and not a fibrous tooth attachment via periodontal ligament that's usually found in mammals and archosaurs. [8]

The marginal tooth rows in mosasauroids like Clidastes are found on the premaxilla, maxilla and the dentary. On the dorsal surface of the dentary there is an interdental ridge that separates successive teeth labially. These interdental ridges serve to separate succeeding teeth that grow upward between existing teeth. [7]

Occurrences

Clidastes is currently found in marine deposits in the US. In past, however, specimens were referred to this genus from Sweden, [9] Germany, [10] Russia, Mexico, [11] and the Maastrichtian of Jordan. [12] However, Lively (2019) questioned the referral of these remains to Clidastes due to their fragmentary nature and lack of apomorphies placing them in the genus to the exclusion of other mosasaurs.

Discovery

E. D. Cope discovered the first specimens of Clidastes propython in 1869 from the Mooreville Chalk in Lowndes County, Alabama. The remains unearthed were that of a juvenile but are one of the best preserved and most complete mosasaurs collected from the state and is regarded as the generic holotype of Clidastes. [4] In 1918, Charles H. Sternberg and his son found additional remains of Clidastes in Kansas. They were surprised to see that it had humeri and femora with round heads, similar to that of mammals. Due to good preservation of the caudals, Sternberg noted that the chevrons along the vertebrae were ankylosed to the center, which is not observed in other mosasaurs. This synapamorphy was believed to aid in fitting the proximal heads snugly into the basins that hew out from the vertebrae almost locking them in place.

Classification and species

The dental and vertebral morphology of Clidastes is closer to that of Mosasaurus than to any other mosasaur, firmly placing it within the subfamily Mosasaurinae. Besides being different in size, the teeth of Campanian species of Mosasaurus (namely M. missouriensis and M. conodon ) differ from those of Clidastes in having a large number of facets that are also more distinct than those in Clidastes. The cervical vertebrae of Clidastes are also different from those in Mosasaurus by being more elongated. [9]

Clidastes is most frequently recovered as one of the most basal mosasaurines, and the most basal hydropedal mosasaurine genus, being more derived than the plesiopedal Dallasaurus but less derived than later genera like Prognathodon or Globidens . The cladogram below is modified from Aaron R. H. Leblanc, Michael W. Caldwell and Nathalie Bardet, 2012: [13]

Restoration of three C. propython Clidastes BW.jpg
Restoration of three C. propython
Mosasaurinae

There is only one named species of Clidastes that is valid, C. propython. Clidastes iguanavus Cope, 1868 was the original type species, but the ICZN was petitioned to make C. propython the new type species by virtue of that species being based on diagnostic remains, which it did vis-à-vis Opinion 1750 (1993). [14] [15]

Invalid species

Size comparison of a specimen of C. propython formerly assigned to the now invalid C. velox Clidastes Scale.svg
Size comparison of a specimen of C. propython formerly assigned to the now invalid C. velox

There is also an undescribed form from the Mooreville Chalk Formation of Alabama that likely represents a new taxon on its own, informally dubbed "Clidastes moorevillensis", which can be distinguished from both C. propython and C. liodontus based on its dental characteristics. [9] Clidastes liodontus was described from the late Coniacian to early Campanian Smoky Hill Chalk Member of the Niobrara Formation in Kansas. [11] There are also earlier occurrences of the species, dated to the Coniacian, and it might thus be ancestral to the later C. propython. [2] C. liodontus grew to about 3–4 meters in length compared to the 4-5 meter (and on occasion larger) length of C. propython. [2] The type specimen of C. liodontus, consisting of maxillae, a premaxilla and dentaries from the Niobrara Formation of Kansas, was housed at the Bayerische Staatssammlung für Paläontologie and may have been destroyed in the Second World War. [6] Russell (1967) [6] diagnosed the species in general as follows: "Premaxilla V-shaped in horizontal cross-section, small rostrum present anterior to premaxillary teeth. Posteroventral portion of root of second premaxillary tooth not exposed on sutural surface with maxilla. Premaxillo-maxillary suture rises posteriorly to position varying from dorsal to fourth to dorsal to sixth maxilIary tooth and parallels longitudinal axis of cranium. Fourteen to fifteen teeth in maxilla. Median dorsal surlace of parietal narrow. Parietal foramen small, close to or distinctly separated from frontal suture. Parietal foramen opens ventrally into brain cavity without broadening into wide excavation. Anterior border of prootic descends beneath prootic incisure without forming shelf. Foramen for cranial nerve VII leaves brain cavity through medial wall of prootic. Infrastapedial process absent on quadrate. Sixteen teeth in dentary." Lively (2019) declared Clidastes liodontus a nomen dubium , while taking note of the nomen nudum status of "moorevillensis", recommending that Clidastes be restricted to C. propython. [16]

Clidastes propython

Fossil cast of a Clidastes propython skeleton next to some ammonite models at the North American Museum of Ancient Life. Clidastes propython skeleton and ammonite models.JPG
Fossil cast of a Clidastes propython skeleton next to some ammonite models at the North American Museum of Ancient Life.

C. propython is the best studied species of the genus, and was for this reason chosen by the ICZN to replace C. iguanavus as the type species.

C. propython is known from the Campanian of the United States (Alabama, Colorado, Texas, Kansas and South Dakota) and of Sweden. [9] [11] The earliest known occurrences of the species are middle Santonian in age and from the Niobrara Formation of Kansas, whilst the latest are Middle to Late Campanian in age, coinciding with a poorly understood middle Campanian intercontinental mosasaur extinction event, which seems to have heavily affected genera such as Clidastes. [9]

Russell (1967) [6] listed the following unambiguous character states for the species: "Premaxilla V-shaped in horizontal cross-section, small. rostrum present anterior to premaxillary teeth. Posteroventral portion of root of second premadlary tooth exposed on sutural surface with maxilla. Premaxillo-maxillary suture rises posteriorly in gentle curve to terminate at point above seventh maxillary tooth. Premaxillary suture of maxilla smoothly keeled and paraIIels longitudinal axis of maxilla. Sixteen-18 teeth in maxilla. Median dorsal surface of parietal moderately broad. Parietal foramen smalI, lies close to suture with frontal and opens ventrally into elliptical excavation in parietal, length of which exceeds that of dorsal opening by about five times. Anterior border of prootic forms shelf beneath prootic incisure, then descends abruptly to basisphenoid. Foramen for cranial nerve VII leaves brain cavity through medial wall of prootic. Infrastapedial process present on quadrate. Seventeen to eighteen teeth in dentary.".

Specimen formerly assigned to C. velox Tylosaurus sp kansas.JPG
Specimen formerly assigned to C. velox

Russell (1967) [6] also referred a large number of fragmentary species of Clidastes to C. propython on the basis of that those with good cranial material were morphologically indistinguishable from the type specimen of C. propython. Among these former species now seen as synonyms of C. propython are C. "cineriarum", C. "dispar", C. "velox", C. "wymani", C. "pumilus", C. "tortor", C. "vymanii, C. "stenops", C. "rex", C. "medius" and C. "westi".

Clidastes iguanavus

The Campanian C. iguanavus is the original type species of Clidastes and poorly known in comparison to C. propython and C. liodontus. The type specimen consists of a single vertebra from the anterior thoracic region, YPM 1601, collected in a marl pit near Swedesboro, New Jersey. The vertebra is similar to that of the other species in its general proportions and the strong zygosphene-zygantrum articulation. C. iguanavus can be differentiated in its central articulations, which are kidney-shaped in outline, with a stronger emargination dorsally for the spinal cord, and in the relatively stout proportions of the centrum. [6]

Related Research Articles

<i>Mosasaurus</i> Extinct genus of marine squamate reptile from the Late Cretaceous

Mosasaurus is the type genus of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. The genus was one of the first Mesozoic marine reptiles known to science—the first fossils of Mosasaurus were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, and were initially thought to be crocodiles or whales. One skull discovered around 1780 was famously nicknamed the "great animal of Maastricht". In 1808, naturalist Georges Cuvier concluded that it belonged to a giant marine lizard with similarities to monitor lizards but otherwise unlike any known living animal. This concept was revolutionary at the time and helped support the then-developing ideas of extinction. Cuvier did not designate a scientific name for the animal; this was done by William Daniel Conybeare in 1822 when he named it Mosasaurus in reference to its origin in fossil deposits near the Meuse River. The exact affinities of Mosasaurus as a squamate remain controversial, and scientists continue to debate whether its closest living relatives are monitor lizards or snakes.

Tylosaurus is a genus of russellosaurine mosasaur that lived about 92 to 66 million years ago during the Turonian to Maastrichtian stages of the Late Cretaceous. Its fossils have been found primarily around North Atlantic Ocean including in North America, Europe, and Africa. The earliest discoveries were possibly made by Native American tribes in the Great Plains, whose creation myths spoke of giant serpentine water monsters turned to stone in ancient times. Paleontologist Edward Drinker Cope first scientifically described fossils of the genus from Kansas in 1869, but the name Tylosaurus was coined by Cope's rival Othniel Charles Marsh.

<span class="mw-page-title-main">Mosasaurinae</span> Subfamily of reptiles

The Mosasaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "mosasaurines" and their fossils have been recovered from every continent except for South America.

<span class="mw-page-title-main">Tylosaurinae</span> Extinct subfamily of lizards

The Tylosaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "tylosaurines" and have been recovered from every continent except for South America. The subfamily includes the genera Tylosaurus, Taniwhasaurus, and Kaikaifilu, although some scientists argue that only Tylosaurus and Taniwhasaurus should be included.

<span class="mw-page-title-main">Halisaurinae</span> Extinct subfamily of lizards

The Halisaurinae are a subfamily of mosasaurs, a group of Late Cretaceous marine lizards. They were small to medium-sized, ranging from just under 3 meters in Eonatator sternbergi to as much as 8 or 9 meters in Pluridens serpentis. They tended to have relatively slender jaws and small, numerous teeth, suggesting a diet of small fish and other prey. Although the skeleton is primitive compared to other Mosasauridae in many respects, halisaurines had the distinctive hypocercal tail of other mosasaurids suggesting good swimming ability, and they persisted alongside other mosasaurs until the end of the Cretaceous. The earliest known remains of halisaurines occur in rocks of Santonian age and the subfamily persists until the latest Maastrichtian. Halisaurines are known from North and South America, Europe, Asia and Africa, indicating a more or less global distribution in the Late Cretaceous. Four genera are currently recognized: Eonatator, Halisaurus, Phosphorosaurus and Pluridens.

Eonatator is an extinct genus of marine lizard belonging to the mosasaur family. It is a close relative of Halisaurus, and part of the same subfamily, the Halisaurinae. It is known from the Late Cretaceous of North America, Colombia and Sweden. Originally, this taxon was included within Halisaurus, but was placed in its own genus, which also led to the subfamily Halisaurinae being created for the two genera.

<i>Russellosaurus</i> Extinct genus of lizards

Russellosaurus is an extinct genus of tethysaurine mosasauroid from the Late Cretaceous of North America. The genus was described from a skull discovered in an exposure of the Arcadia Park Shale at Cedar Hill, Dallas County in the south-central part of the DFW Metroplex in Texas, United States. The skull was found in 1992 by a member of the Dallas Paleontological Society, who then donated to the museum. Other fragmentary specimens of Russelosaurus have been recovered from the slightly older Kamp Ranch Limestone at two other localities in the Dallas area.

<i>Globidens</i> Extinct genus of lizards

Globidens is an extinct genus of mosasaurid oceanic lizard classified as part of the Globidensini tribe in the Mosasaurinae subfamily. Globidens belongs to the family Mosasauridae, which consists of several genera of predatory marine lizards of various sizes that were prevalent during the Late Cretaceous. Specimens of Globidens have been discovered in Angola, Brazil, Morocco, Syria and the United States. Among mosasaurs, Globidens is probably most well known for the highly rounded, globe-like teeth that give it its name.

<i>Prognathodon</i> Extinct genus of lizards

Prognathodon is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like Mosasaurus and Clidastes. Prognathodon has been recovered from deposits ranging in age from the Campanian to the Maastrichtian in the Middle East, Europe, New Zealand, and North America.

Carinodens is an extinct genus of Cretaceous marine lizard belonging to the mosasaur family. "Carinodens" means "keel teeth" and was named in 1969 as a replacement name for Compressidens, "compressed teeth", which was already in use for a gadilidan scaphopod mollusk.

<i>Pluridens</i> Extinct genus of lizards

Pluridens is an extinct genus of marine lizard belonging to the Mosasauridae. Pluridens is placed in the subfamily Halisaurinae with the genera Phosphorosaurus, Eonatator and Halisaurus. Compared to related halisaurines, Pluridens had longer jaws with more teeth, and smaller eyes. It also grew large size, measuring 5–6 m (16–20 ft) long and perhaps over 9 m (30 ft) in some individuals. The jaws in some specimens are robust, and sometimes show injuries suggestive of combat. The jaws may have been used for fighting over mates or territories.

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

Anatosuchus is an extinct genus of notosuchian crocodyliforms 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.

Goronyosaurus is an extinct genus of marine lizard belonging to the mosasaur family. Fossils of Goronyosaurus are exclusively known from the Late Maastrichtian of the Iullemmeden Basin in West Africa, specifically the Dukamaje Formation of Niger and Nigeria and Farin Doutchi Formation of Niger. The type specimen was first described in 1930 as Mosasaurus nigeriensis, but subsequent remains revealed a highly unique set of adaptations that prompted the species to be reclassified as the only species of the new genus Goronyosaurus in 1972. These unique adaptations have made Goronyosaurus notoriously difficult to classify within the Mosasauridae and it is often left out of phylogenetic analyses, although most authors agree that Goronyosaurus belonged to Mosasauridae.

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

Adamantinasuchus is an extinct genus of notosuchian crocodylomorph from and named after the Late Cretaceous Adamantina Formation of Brazil. It is known from only one fossil, holotype UFRJ-DG 107-R, collected by William Nava. The fossil consists of a partial skull, fragmentary limb bones and a few broken vertebrae, and was found 25 kilometres (16 mi) southwest of the town of Marilia, near a reservoir dam. Adamantinasuchus was approximately 60 centimetres (24 in) long from nose to tail, and would have only weighed a few kilograms.

<i>Taniwhasaurus</i> Extinct genus of marine squamate reptiles

Taniwhasaurus is an extinct genus of mosasaurs that lived during the Campanian stage of the Late Cretaceous. It is a member of the subfamily Tylosaurinae, a lineage of mosasaurs characterized by a long toothless conical rostrum. Two valid species are attached to the genus, T. oweni and T. antarcticus, known respectively from the fossil record of present-day New Zealand and Antarctica. Two other species have been nominally classified within the genus, T. 'capensis' and T. 'mikasaensis', recorded in present-day South Africa and Japan, but their attribution remains problematic due to the fragmentary state of their fossils. The generic name literally means "taniwha lizard", referring to a supernatural aquatic creature from Māori mythology.

<i>Plesiotylosaurus</i> Extinct genus of lizards

Plesiotylosaurus, meaning "near Tylosaurus", is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like Mosasaurus and Prognathodon. The genus contains one species, Plesiotylosaurus crassidens, recovered from deposits of Middle Maastrichtian age in the Moreno Formation in California.

Eremiasaurus is a genus of mosasaurs, an extinct group of marine reptiles. It lived during the Maastrichtian stage of the Late Cretaceous in what is now North Africa. Only one species is known, E. heterodontus, described in 2012 from two remarkably complete fossil specimens discovered in the Ouled Abdoun Basin, Morocco. This site is known to have delivered a significant number of other related mosasaurs.

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.

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>Arisierpeton</i> Extinct genus of synapsids

Arisierpeton is an extinct genus of synapsids from the Early Permian Garber Formation of Richards Spur, Oklahoma. It contains a single species, Arisierpeton simplex.

References

  1. "Sehnde-Höver (Scholz collection) (Cretaceous of Germany)". PBDB.org.
  2. 1 2 3 "Rapid Evolution of Mosasaurs". oceansofkansas.com. Retrieved 2017-09-22.
  3. Taylor, L.T.; Minzoni, R.T.; Suarez, C.A.; Gonzalez, L.A.; Martin, L.D.; Lambert, W.J.; Ehret, D.J.; Harrell, T.L. "Oxygen isotopes from the teeth of Cretaceous marine lizards reveal their migration and consumption of freshwater in the Western Interior Seaway, North America". Palaeogeography, Palaeoclimatology, Palaeoecology. 573. doi:10.1016/j.palaeo.2021.110406.
  4. 1 2 Cope, E.D. 1868. On new species of extinct reptiles. Proceedings of the Academy of Natural Sciences of Philadelphia 20: 181
  5. Wright, K. R. (September 23, 1988). The First Record of Clidastes liodontus (Squamata, Mosasauridae) from the Eastern United States. Journal of Vertebrate Paleontology, 8, 3, 343-34
  6. 1 2 3 4 5 6 7 Russell, Dale. A. (6 November 1967). "Systematics and Morphology of American Mosasaurs" (PDF). Bulletin of the Peabody Museum of Natural History (Yale University). Archived from the original (PDF) on 21 October 2022. Retrieved 21 October 2022.
  7. 1 2 3 4 Olivier, R., & Maureen, K. (December 01, 2005). Tooth Replacement in the Late Cretaceous Mosasaur Clidastes. Journal of Herpetology, 39, 4.)
  8. Luan, X., Walker, C., Dangaria, S., Ito, Y., Druzinsky, R., Jarosius, K., Lesot, H Rieppel, O. (January 01, 2009). The mosasaur tooth attachment apparatus as paradigm for the evolution of the gnathostome periodontium. Evolution & Development, 11, 3.)
  9. 1 2 3 4 5 Lindgren, J., & Siverson, M. (January 01, 2004). The first record of the mosasaur Clidastes from Europe and its palaeogeographical implications. Acta Palaeontologica Polonica, 49, 219-234.
  10. Caldwell, M.W., & Diedrich, C.G. 2005. Remains of Clidastes Cope, 1868, an unexpected mosasaur in the upper Campanian of NW Germany. (Igitur.) Igitur.
  11. 1 2 3 "Fossilworks: Clidastes". fossilworks.org. Retrieved 17 December 2021.
  12. Kaddumi, H.F. (2006). "A new genus and species of gigantic marine turtles (Chelonioidea: Cheloniidae) from the Maastrichtian of the Harrana Fauna–Jordan" (PDF). Vertebrate Paleontology. 3 (1). Archived from the original (PDF) on 2012-02-24. Retrieved 2017-09-22.
  13. Aaron R. H. Leblanc, Michael W. Caldwell and Nathalie Bardet (2012). "A new mosasaurine from the Maastrichtian (Upper Cretaceous) phosphates of Morocco and its implications for mosasaurine systematics". Journal of Vertebrate Paleontology. 32 (1): 82–104. doi:10.1080/02724634.2012.624145.
  14. Kiernan, C.R. 1992. Clidastes Cope, 1868 (Reptilia, Sauria):proposed designation of Clidastes propython Cope, 1869 as the type species. Bulletin of Zoological Nomenclature 49:137-139.
  15. ICZN Opinion 1750. 1993. Clidastes Cope, 1868 (Reptilia, Sauria):C. propython Cope, 1869 designated as the type species. Bulletin of Zoological Nomenclature 50: 297.
  16. Joshua R. Lively (2019). "Taxonomy and historical inertia: Clidastes (Squamata: Mosasauridae) as a case study of problematic paleobiological taxonomy". Alcheringa: An Australasian Journal of Palaeontology. in press. doi:10.1080/03115518.2018.1549685.

Notes

  1. In mosasaurs, the terms "hydropedal" and "plesiopedal" refers to varying limb conditions and varying degrees of adaptations for marine life. Plesiopedal mosasaurs, such as Dallasaurus or Tethysaurus were primitive and largely coastal, while later hydropedal mosasaurs were streamlined and well-adapted to marine life.

Commons-logo.svg Media related to Clidastes at Wikimedia Commons