Dyrosauridae

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Dyrosauridae
Temporal range: 83.5–47  Ma
Arambourgisuchus.jpg
Skull of the dyrosaurid Arambourgisuchus khouribgaensis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Crocodylomorpha
Clade: Crocodyliformes
Suborder:† Tethysuchia
Family:† Dyrosauridae
de Stefano, 1903
Genera

Dyrosauridae is a family of extinct neosuchian crocodyliforms that lived from the Campanian to the Eocene. Dyrosaurid fossils are globally distributed, having been found in Africa, Asia, Europe, North America and South America. Over a dozen species are currently known, varying greatly in overall size and cranial shape. A majority were aquatic, some terrestrial and others fully marine (see locomotion below), with species inhabiting both freshwater and marine environments. Ocean-dwelling dyrosaurids were among the few marine reptiles to survive the Cretaceous–Paleogene extinction event.

Contents

The dyrosaurids were a group of mostly marine, long jawed, crocodile-like quadrupeds up to 6 metres (20 ft) long. [1] The largest dyrosaurid was probably Phosphatosaurus estimated at 9 m (30 ft) in length. [2] [3] Based on bone tissue evidence, it has been hypothesized that they were slow-growing [4] near-shore marine animals with interlocking closed jaws, [4] able to swim as well as walk on land. External nostrils at the posterior end of its snout and an internal naris in its pterygoid indicated a habit of hunting while swimming with the top of the head above the water, enabling it to breathe while stalking prey. [1]

Overview

Restoration of Dyrosaurus Dyrosaurus BW.jpg
Restoration of Dyrosaurus

Dyrosaurids are known to have a very characteristic skull shape with a long and thin snout that is approximately 68% of the total skull length. The most anterior part of the skull and snout is the external naris followed posteriorly by two premaxillae bones until they reach two maxillae bones separated by a single nasal bone. [1]

Typical in dyrosaurids is a single nasal element with a characteristic collection of small pits and a constant width until it widens to contact the lacrimal bones, then tapering off for a short distance until it meets the boundary of the frontals and prefrontals. [1]

Tooth Dyrosaurus tooth.jpg
Tooth

Dyrosaurs have a premaxilla with shallow pits that extend posterior to the third maxillary alveoli. There are two premaxillae that are narrow as compared to the maxillary bones and extend in the two long maxilla bones which separated by the single nasal bone. The last premaxilla and first maxilla are widely separated by a fourth dentary tooth. Alveoli are widely spaced anteriorly and the space between them decreases posteriorly from the fifteenth alveolus with the diameter remaining constant. [1]

The maxilla is long (approx. two and a half times the length of jugal) and forms most of the lateral margin of the skull. [5] According to Jouve and Barbosa and perhaps depending on the age of the animal, each maxilla bears 13–19 teeth. [5]

An important feature of the dyrosaurid dentition are deep occlusal pits, present particularly in the posterior region of the maxillae that get less pronounced anteriorly. The pits are indicative of an interlocking closed jaw for dyrosaurids because the pits give a way for the upper and lower jaws to alternate. Although they are still present in dyrosaurus phosphaticus, this feature of deep occlusal pits become less developed and broad. [5] Dyrosaurus teeth are homodont, conical, long, and slender, with asymmetrically labial and lingual surfaces. Posterior teeth are shorter and more compressed than anterior tooth indicating that the tooth size decreased anterior to posterior.

Jaw fragment Dyrosaurus jaw.jpg
Jaw fragment

Dyrosaurs have a snout to skull length of about 68% and the genus Rhabdognathus and Atlantosuchus, Dyrosaurus and Arambourgisuchus have the largest snout proportions of all dyrosaurids. Snout length was previously used it to establish dyrosaurid relationships, while considering the lengthening of the snout to be a ‘more evolved’ character. This was not congruent with Jouve's conclusion which was that the longest snout is actually the primitive condition so the shorter or longer snout appears independently at least four times in dyrosaurid evolution. [6]

Paleobiogeography

Dyrosaurids were once considered an African group, but discoveries made starting from the 2000s indicate they inhabited the majority of the continents. [7] In fact, basal forms suggest that their cradle may have been North America.

General

GenusStatusAgeLocationDescriptionImages
Acherontisuchus Valid Paleocene Flag of Colombia.svg  Colombia A large-bodied, long-snouted freshwater dyrosaurid from the Cerrejón Formation
Aigialosuchus Valid Campanian Flag of Sweden.svg  Sweden A marine dyrosaurid from the Kristianstad Basin
Anthracosuchus Valid Paleocene Flag of Colombia.svg  Colombia A short-snouted freshwater dyrosaurid from the Cerrejón Formation
Arambourgisuchus Valid Paleocene Flag of Morocco.svg  Morocco A long-snouted marine dyrosaurid
Atlantosuchus Valid Paleocene Flag of Morocco.svg  Morocco A long-snouted marine dyrosaurid with the longest snout length in proportion to body size of any dyrosaurid
Brachiosuchus Valid Late Cretaceous Flag of Sudan.svg  Sudan A long-snouted, long-armed dyrosaurid with the longest arms of any dyrosaurid
Cerrejonisuchus Valid Paleocene Flag of Colombia.svg  Colombia A small-bodied, short-snouted freshwater dyrosaurid from the Cerrejón Formation
Chenanisuchus Valid Maastrichtian–Paleocene Flag of Mali.svg  Mali
Flag of Morocco.svg  Morocco 		The genus spans the K–Pg boundary Chenanisuchus BW.jpg
Congosaurus Valid Paleocene Flag of Angola.svg  Angola
Dyrosaurus Valid Eocene Flag of Algeria.svg  Algeria
Flag of Tunisia.svg  Tunisia 		A large-bodied, long-snouted marine dyrosaurid Dyrosaurus BW.jpg
Guarinisuchus Valid Paleocene Flag of Brazil.svg  Brazil probable Junior synonym of Hyposaurus derbianus Guarinisuchus munizi.jpg
Hyposaurus Valid Maastrichtian–Paleocene Flag of Brazil.svg  Brazil
Flag of Mali.svg  Mali
Flag of Nigeria.svg  Nigeria
Flag of the United States.svg  US 		Five species have been named, the most of any dyrosaurid genus; the genus spans the K–Pg boundary
Phosphatosaurus Valid Eocene Flag of Mali.svg  Mali
Flag of Tunisia.svg  Tunisia 		A large-bodied, long-snouted marine dyrosaurid with blunt teeth and a spoon-shaped snout tip
Rhabdognathus Valid Maastrichtian–Paleogene Flag of Mali.svg  Mali
Flag of Nigeria.svg  Nigeria 		A large-bodied, long-snouted marine dyrosaurid; the genus spans the K–Pg boundary
Sokotosaurus Junior synonym Junior synonym of Hyposaurus
Sokotosuchus Valid Maastrichtian Flag of Nigeria.svg  Nigeria A long-snouted marine dyrosaurid
Tilemsisuchus Valid Eocene Flag of Mali.svg  Mali

Phylogeny

Jouve et al. (2005) diagnose Dyrosauridae as a clade based on the following seven synapomorphies or shared characters:

Jouve et al. 2020 provide a comprehensive analysis of the relationships of dyrosaurids, shown below. Note the former dyrosaurids Sabinosuchus and Fortignathus are recovered as a pholidosaurid and a peirosaurid, respectively. [8]

Dyrosauridae

Palaeobiology

Growth

Skull Dyrosaurus skull.JPG
Skull

Evidence for the semi-aquatic life of dyrosaurids comes from careful analysis of bone structure. There are two types of structural bone organization that can occur in aquatic tetrapods: osteoporotic or pachyostotic. Osteoporotic bone is spongy and porous whereas pachyostotic involves an increase in skeletal mass. Spongy/porous bone such as osteoporotic is associated with faster swimming and better maneuverability in water because of the reduction in bone tissue, many extant cetaceans and marine turtles have osteoporotic bone which enables them to be good swimmers. Pachyostotic bone is a general/local increase in skeletal mass which can be caused by osteosclerosis (inner compaction of bone), pachyostosis (hyperplasy of compact cortices) or pachyeosclerosis (combination of the two). Research on dyrosaur bone performed by Rafael César Lima Pedroso de Andrade and Juliana Manso Sayao revealed that this family had osteoporotic bone tissue indicative of a fast-swimming ecology as well as some osteosclerosis which is a component of pachyostotic bone tissue. Osteoporosis is associated with a fully aquatic lifestyle whereas pachyostotic is not fully aquatic but is associated with fast swimming ecology. Therefore, dyrosaurs are semi-aquatic fast swimmers as indicated by their bone structure. Other evidence for near shore, semi-aquatic lifestyle is where the fossils are found, often in transitional marine sediments. [4] -using axial frequency swimming (that used primarily by extant crocodylians) with a greater undulatory motion and frequency of the tail due to highly developed musculature allowing a more powerful forward thrust. [4]

Dyrosaurids have a tissue pattern that is indicative of a slow-growth animal that was determined by careful analysis of a right femur and left tibia. In the left tibia, the cortex had a lamellar zonal bone with five lines of arrested growth (LAGs) which were spaced 300 mm apart, well as a clear vascular networks of primary osteons that decreased in density towards the membrane (periostially). The right femur had double LAGs and an EFS later as well as secondary osteons occurring in the deep cortex and the spongiosa. This tissue growth pattern is a common characteristic of slow growing animals. [4]

Habitat

Dyrosaurids are found in transitional marine sediments from the Late Cretaceous to lower Eocene. [4] This family is known mainly from Maastrichthian deposits in New Jersey and the late Cretaceous to early Paleogene rock from the Tethys Sea in northern and western Africa. [4] Fossils have also been found from the Paleocene and Eocene strata of Pakistan, as well as South America, Brazil, India, Southern Asia as well as coastal. Generally dyrosaurids are recovered from coastal and estuarine deposits through North Africa and the Middle East confirming their existence as semi-aquatic animals. [9]

Dyrosauridae had its greatest taxonomic diversity during the Early Paleogene but it appears as though the clade was able to obtain a greater and more widespread geographic distribution during the Late Cretaceous. The earliest records of dyrosaurids are either in or close to Africa with fragmentary occurrences from the Cenomanian of Sudan and Portugal and several other pre-Maastrichtian, Late Cretaceous discoveries in Egypt. Later, by the Maastrichtian of North America, the record of dyrosaurids became more complete by establishing a widespread distribution that appears to be maintained through the Paleocene and Eocene. [10]

Dyrosaurids have also been found from non-marine sediments. In northern Sudan, dyrosaurids are known from fluvial deposits, indicating that they lived in a river setting. [11] Bones from indeterminate dyrosaurids have been found in inland deposits in Pakistan as well. Some dyrosaurids, such as those from the Umm Himar Formation in Saudi Arabia, inhabited estuarine environments near the coast. The recently named dyrosaurids Cerrejonisuchus and Acherontisuchus have been recovered from the Cerrejón Formation in northwestern Colombia, which is thought to represent a transitional marine-freshwater environment surrounded by rainforest more inland than the estuarine environment of the Umm Himar Formation. [12] Cerrejonisuchus and Acherontisuchus lived in a neotropical setting during a time when global temperatures were much warmer than they are today. [13] [14]

Reproduction

In 1978, it was proposed that dyrosaurids lived as adults in the ocean but reproduced in inland freshwater environments. Remains belonging to small-bodied dyrosaurids from Pakistan were interpreted as juveniles. Their presence in inland deposits was viewed as evidence that dyrosaurids hatched far from the ocean. [15] From the lower Eocene Oulad Abdoun Basin, there are very few juvenile dyrosaurids, but numerous similarly-sized adult specimens. This has furthered the assumption that juveniles lived in freshwater environments and adults lived in marine environments. [16] Recently however, the large-bodied and fully mature dyrosaurids of the Cerrejón Formation have shown that some dyrosaurids lived their entire lives in inland environments, never returning to the coast. [17]

Locomotion

A study on Cerrejonisuchus suggest this genus was more terrestrial than other dyrosaurids, and also shows that modern crocodylians are not good functional analogues for Dyrosauridae. [18]

Related Research Articles

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

Chenanisuchus is a genus of dyrosaurid crocodyliform from the Late Cretaceous of Mali and the Late Palaeocene of Sidi Chenane in Morocco. It was described in 2005, after expeditions uncovered it in 2000.

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

Arambourgisuchus is an extinct genus of dyrosaurid crocodylomorph from the late Palaeocene of Morocco, found in the region of Sidi Chenane in 2000, following collaboration by French and Moroccan institutions, and described in 2005 by a team led by palaeontologist Stéphane Jouve. Arambourgisuchus was a large animal with an elongated skull 1 meter in length.

Elosuchus is an extinct genus of neosuchian crocodyliform that lived during the Middle Cretaceous of what is now Africa.

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

Dyrosaurus is a genus of extinct crocodylomorph that lived during the early Eocene. The name Dyrosaurus comes from sauros (σαῦρος) the Greek for lizard or reptile, and Dyr for Djebel Dyr (mountain) close to where the type species was discovered. It was a large reptile with an estimated body length of 6.5 metres (21 ft).

Hyposaurus is a genus of extinct marine dyrosaurid crocodyliform. Fossils have been found in Paleocene aged rocks of the Iullemmeden Basin in West Africa, Campanian–Maastrichtian Shendi Formation of Sudan and Maastrichtian through Danian strata in New Jersey, Alabama and South Carolina. Isolated teeth comparable to Hyposaurus have also been found in Thanetian strata of Virginia. It was related to Dyrosaurus. The priority of the species H. rogersii has been debated, however there is no sound basis for the recognition of more than one species from North America. The other North American species are therefore considered nomina vana.

Argochampsa is an extinct genus of eusuchian crocodylomorph, usually regarded as a gavialoid crocodilian, related to modern gharials. It lived in the Paleocene of Morocco. Described by Hua and Jouve in 2004, the type species is A. krebsi, with the species named for Bernard Krebs. Argochampsa had a long narrow snout, and appears to have been marine in habits.

<span class="mw-page-title-main">Pholidosauridae</span> Extinct family of reptiles

Pholidosauridae is an extinct family of aquatic neosuchian mesoeucrocodylian crocodylomorphs. Fossils have been found in Europe, Africa, North America and South America. The pholidosaurids first appeared in the fossil record during the Bathonian stage of the Middle Jurassic. Jouve & Jalil (2020) described postcranial material of a pholidosaurid from the Paleocene (Danian) of Ouled Abdoun Basin (Morocco), representing the most recent record of the family. The authors also reinterpreted putative Maastrichtian dyrosaurid Sabinosuchus as a pholidosaurid, and argued that at least two independent pholidosaurid lineages reached the Maastrichtian, among which one survived the Cretaceous–Paleogene extinction event. Before the publication of this study it was thought that the family became extinct during the Late Turonian stage of the Late Cretaceous.

Atlantosuchus is an extinct genus of dyrosaurid crocodylomorph from Morocco. One defining characteristic that distinguishes it from other long-snouted dyrosaurids was its proportionally elongate snout, the longest in proportion to body size of any dyrosaurid. Rhabdognathus, a hyposaurine dyrosaurid, is believed to have been the closest relative of the genus.

Congosaurus is an extinct genus of dyrosaurid mesoeucrocodylian. Fossils have been found from Lândana, in Angola and date back to the Paleocene epoch. In 1952 and 1964 Congosaurus was proposed to be synonymous with Dyrosaurus. The genus was later thought synonymous with Hyposaurus in 1976 and 1980. It has since been proven a distinct genus of dyrosaurid separate from both Dyrosaurus and Hyposaurus.

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

Pholidosaurus is an extinct genus of neosuchian crocodylomorph. It is the type genus of the family Pholidosauridae. Fossils have been found in northwestern Germany. The genus is known to have existed during the Berriasian-Albian stages of the Early Cretaceous. Fossil material found from the Annero and Jydegård Formations in Skåne, Sweden and on the island of Bornholm, Denmark, have been referred to as a mesoeucrocodylian, and possibly represent the genus Pholidosaurus.

Phosphatosaurus is an extinct genus of dyrosaurid crocodylomorph. It existed during the early Eocene, with fossils having been found from North Africa in Tunisia and Mali. Named in 1955, Phosphatosaurus is a monotypic genus; the type species is P. gavialoides. A specimen has been discovered from Niger, but it cannot be classified at the species level.

Cerrejonisuchus is an extinct genus of dyrosaurid crocodylomorph. It is known from a complete skull and mandible from the Cerrejón Formation in northeastern Colombia, which is Paleocene in age. Specimens belonging to Cerrejonisuchus and to several other dyrosaurids have been found from the Cerrejón open-pit coal mine in La Guajira. The length of the rostrum is only 54-59% of the total length of the skull, making the snout of Cerrejonisuchus the shortest of all dyrosaurids.

Rhabdognathus is an extinct genus of dyrosaurid crocodylomorph. It is known from rocks dating to the Paleocene epoch from western Africa, and specimens dating back to the Maastrichtian era were identified in 2008. It was named by Swinton in 1930 for a lower jaw fragment from Nigeria. The type species is Rhabdognathus rarus. Stéphane Jouve subsequently assessed R. rarus as indeterminate at the species level, but not at the genus level, and thus dubious. Two skulls which were assigned to the genus Rhabdognathus but which could not be shown to be identical to R. rarus were given new species: R. aslerensis and R. keiniensis, both from Mali. The genus formerly contained the species Rhabdognathus compressus, which was reassigned to Congosaurus compressus after analysis of the lower jaw of a specimen found that it was more similar to that of the species Congosaurus bequaerti. Rhabdognathus is believed to be the closest relative to the extinct Atlantosuchus.

Acherontisuchus is an extinct genus of dyrosaurid neosuchian from Middle to Late Paleocene deposits of Colombia. The only known species is A. guajiraensis, whose name means "Acheron crocodile of the Guajira Peninsula".

<i>Ocepeia</i> Extinct Afrotherian mammal

Ocepeia is an extinct genus of afrotherian mammal that lived in present-day Morocco during the middle Paleocene epoch, approximately 60 million years ago. First named and described in 2001, the type species is O. daouiensis from the Selandian stage of Morocco's Ouled Abdoun Basin. A second, larger species, O. grandis, is known from the Thanetian, a slightly younger stage in the same area. In life, the two species are estimated to have weighed about 3.5 kg (7.7 lb) and 10 kg (22 lb), respectively, and are believed to have been specialized leaf-eaters. The fossil skulls of Ocepeia are the oldest known afrotherian skulls, and the best-known of any Paleocene mammal in Africa.

<span class="mw-page-title-main">Ouled Abdoun Basin</span> Phosphate basin in Morocco

The Oulad Abdoun Basin is a phosphate sedimentary basin located in Morocco, near the city of Khouribga. It is the largest in Morocco, comprising 44% of Morocco's phosphate reserves, and at least 26.8 billion tons of phosphate. It is also known as an important site for vertebrate fossils, with deposits ranging from the Late Cretaceous (Cenomanian-Turonian) to the Eocene epoch (Ypresian), a period of about 25 million years.

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

Anthracosuchus is an extinct genus of dyrosaurid crocodyliform from the Paleocene of Colombia. Remains of Anthracosuchus balrogus, the only known species, come from the Cerrejón Formation in the Cerrejón mine, and include four fossil specimens with partial skulls. Anthracosuchus differs from other dyrosaurids in having an extremely short (brevirostrine) snout, widely spaced eye sockets with bony protuberances around them, and osteoderms that are smooth and thick. It is one of the most basal dyrosaurids along with Chenanisuchus and Cerrejonisuchus.

<span class="mw-page-title-main">Coelognathosuchia</span> Extinct clade of reptiles

Coelognathosuchia is an extinct clade of neosuchian crocodyliforms that includes all taxa more closely related to the family Pholidosauridae than to Bernissartia fagesii or Eusuchia. Martin et al. (2014) named the clade after finding goniopholidids and pholidosaurids to group together in their phylogenetic analysis of crocodyliform evolutionary relationships. In their analysis, Pholidosauridae was monophyletic and Goniopholididae was paraphyletic, being an assemblage of successively more basal taxa within Coelognathosuchia. Coelognathosuchia itself was positioned near the base of the larger clade Neosuchia as the sister group to a clade containing the Early Cretaceous neosuchian Bernissartia and Eusuchia, the group that includes all modern crocodilians and their closest extinct relatives.

The Maria Farinha Formation is a geological formation of the Parnaíba Basin in Pernambuco, northeastern Brazil whose strata date back to the Danian stage of the Paleocene, or Tiupampan in the SALMA classification.

Sabinosuchus is a genus of Mesoeucrocodylian, from the Maastrichtian Escondido Formation of Coahuila, Mexico, with Sabinosuchus coahuilensis as the type species. First described as a putative dyrosaurid by Shiller II et al. (2016), it was later recovered as a pholidosaurid by Jouve & Jalil (2020).

References

  1. 1 2 3 4 5 Jouve, Stéphane (March 2005). "A new description of the skull of Dyrosaurus phosphaticus (Thomas, 1893) (Mesoeucrocodylia: Dyrosauridae) from the Lower Eocene of North Africa". Canadian Journal of Earth Sciences. 42 (3): 323–337. Bibcode:2005CaJES..42..323J. doi:10.1139/e05-008. ISSN   0008-4077 . Retrieved March 22, 2021.
  2. ↑ Buffetaut, E. (1978). "Les Dyrosauridae (Crocodylia, Mesosuchia) des phosphates de l'Eocène inférieur de Tunisie: Dyrosaurus, Rhabdognathus, Phosphatosaurus". Géologie Méditerranéenne. 5 (2): 237–256. doi:10.3406/geolm.1978.1046.
  3. ↑ Martin, Jeremy E.; Antoine, Pierre-Olivier; Perrier, Vincent; Welcomme, Jean-Loup; Metais, Gregoire; Marivaux, Laurent (2019-07-04). "A large crocodyloid from the Oligocene of the Bugti Hills, Pakistan" (PDF). Journal of Vertebrate Paleontology. 39 (4): e1671427. Bibcode:2019JVPal..39E1427M. doi:10.1080/02724634.2019.1671427. ISSN   0272-4634. S2CID   209439989.
  4. 1 2 3 4 5 6 7 de Andrade, Rafael César Lima Pedroso; Sayão, Juliana Manso (2014-07-17). "Paleohistology and Lifestyle Inferences of a Dyrosaurid (Archosauria: Crocodylomorpha) from Paraíba Basin (Northeastern Brazil)". PLOS ONE. 9 (7): e102189. Bibcode:2014PLoSO...9j2189A. doi: 10.1371/journal.pone.0102189 . ISSN   1932-6203. PMC   4102515 . PMID   25032965.
  5. 1 2 3 Barbosa, José Antonio; Kellner, Alexander Wilhelm Armin; Viana, Maria Somália Sales (2008). "New dyrosaurid crocodylomorph and evidences for faunal turnover at the K–P transition in Brazil". Proceedings of the Royal Society B: Biological Sciences. 275 (1641): 1385–1391. doi:10.1098/rspb.2008.0110. PMC   2602706 . PMID   18364311.
  6. ↑ Jouve, Stephane; Bouya, Baâdi; Amaghzaz, Mbarek (March 2008). "A Long-Snouted Dyrosaurid (Crocodyliformes, Mesoeucrocodylia) from the Paleocene of Morocco: Phylogenetic and Palaeobiogeographic Implications". Palaeontology. 51 (2): 281–294. Bibcode:2008Palgy..51..281J. doi: 10.1111/j.1475-4983.2007.00747.x .
  7. ↑ Jouve et al. (2008)
  8. ↑ Jouve, Stéphane; de Muizon, Christian; Cespedes-Paz, Ricardo; Sossa-Soruco, Víctor; Knoll, Stephane (2020-10-19). "The longirostrine crocodyliforms from Bolivia and their evolution through the Cretaceous–Palaeogene boundary". Zoological Journal of the Linnean Society. 192 (zlaa081): 475–509. doi:10.1093/zoolinnean/zlaa081. ISSN   0024-4082.
  9. ↑ Lamanna, Matthew C.; Smith, Joshua B.; Attia, Yousry S.; Dodson, Peter (2004-09-10). "From dinosaurs to dyrosaurids (Crocodyliformes): removal of the post-Cenomanian (Late Cretaceous) record of Ornithischia from Africa" (PDF). Journal of Vertebrate Paleontology. 24 (3): 764–768. doi:10.1671/0272-4634(2004)024[0764:FDTDCR]2.0.CO;2. ISSN   0272-4634. S2CID   16525132.
  10. ↑ Khosla, Ashu; Sertich, Joseph J. W.; Prasad, Guntupalli V. R.; Verma, Omkar (2009-12-12). "Dyrosaurid remains from the Intertrappean Beds of India and the Late Cretaceous distribution of Dyrosauridae". Journal of Vertebrate Paleontology. 29 (4): 1321–1326. Bibcode:2009JVPal..29.1321K. doi:10.1671/039.029.0416. ISSN   0272-4634. S2CID   130987967.
  11. ↑ Buffetaut, E.; Bussert, R.; Brinkmann, W. (1990). "A new nonmarine vertebrate fauna in the Upper Cretaceous of northern Sudan". Berliner Geowissenschaftlische Abhandlungen. 120: 183–202.
  12. ↑ Hastings, A. K; Bloch, J. I.; Cadena, E. A.; Jaramillo, C. A. (2010). "A new small short-snouted dyrosaurid (Crocodylomorpha, Mesoeucrocodylia) from the Paleocene of northeastern Colombia". Journal of Vertebrate Paleontology. 30 (1): 139–162. Bibcode:2010JVPal..30..139H. doi: 10.1080/02724630903409204 . S2CID   84705605.
  13. ↑ Head, J. J.; Bloch, J. I.; Hastings, A. K.; Borque, J. R.; Cadena, E. A.; Herrera, F. A.; Polly, P. D.; Jaramillo, C. A. (2009). "Giant boid snake from the Palaeocene neotropics reveals hotter past equatorial temperatures". Nature. 457 (7230): 715–717. Bibcode:2009Natur.457..715H. doi:10.1038/nature07671. PMID   19194448. S2CID   4381423.
  14. ↑ Kanapaux, B. (February 2, 2010). "UF researchers: Ancient crocodile relative likely food source for Titanoboa". University of Florida News. Archived from the original on June 8, 2010. Retrieved February 3, 2010.
  15. ↑ Buffetaut, E. (1978). "Crocodilian remains from the Eocene of Pakistan". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 156: 262–283.
  16. ↑ Jouve, Stephanie; Bardet, Nathalie; Jalil, Nour-Eddine; Superbiola, Xabier Pereda; Bouya, Baâdi and Amagzaz, Mbarek. 2008. The oldest African crocodylian: phylogeny, paleobiogeography, and differential survivorship of marine reptiles through the Cretaceous–Tertiary boundary. Journal of Vertebrate Paleontology 28(2):409–421, June 2008
  17. ↑ Hastings, A.K.; Bloch, J.; Jaramillo, C.A. (2011). "A new longirostrine dyrosaurid (Crocodylomorpha, Mesoeucrocodylia) from the Paleocene of north-eastern Colombia: biogeographic and behavioural implications for new-world dyrosauridae". Palaeontology. 54 (5): 1095–116. Bibcode:2011Palgy..54.1095H. doi:10.1111/j.1475-4983.2011.01092.x.
  18. ↑ Scavezzoni, Isaure; Fischer, Valentin (2021). "The postcranial skeleton of Cerrejonisuchus improcerus (Crocodyliformes: Dyrosauridae) and the unusual anatomy of dyrosaurids". PeerJ. 9: e11222. doi: 10.7717/peerj.11222 . PMC   8117932 . PMID   34026348.
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