Dyrosauridae

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Dyrosauridae Fossil range: Late Cretaceous - Eocene
Dyrosaurus
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Subclass: Diapsida Superorder: Crocodylomorpha (unranked) Neosuchia Family: Dyrosauridae de Stefano, 1903
Genera
Arambourgisuchus Atlantosuchus Chenanisuchus Congosaurus Dyrosaurus Guarinisuchus Hyposaurus Phosphatosaurus Rhabdognathus Sokotosuchus Tilemsisuchus

Dyrosauridae is a family of extinct neosuchian crocodyliforms that lived from the Late Cretaceous (Maastrichtian) to the Eocene. Fossils of this group have been found in almost every continent, specifically Africa, Asia, Europe, North America and South America.

Contents 1 History of the group 2 Systematics 3 Palaeobiology 4 References 5 External links

[edit] History of the group

Dyrosaurids were once considered an African group, but more recent discoveries indicate they inhabited the majority of the continents. In fact, basal forms suggest that their cradle may have been North America.

[edit] Systematics

This group is poorly known, due to poor preservation of remains despite being relatively abundant. Despite this, Jouve et al. (2005) found Dyrosauridae to be a clade, based on seven synapomorphies:

• Posteromedial wing of the retroarticular process dorsally situated ventrally on the retroarticular process
• Occipital tuberosities small
• Exoccipital participates largely to the occipital condyle
• Supratemporal fenestra anteroposteriorly strongly elongated
• Symphysis about as wide as high
• Quadratojugal participates largely to the cranial condyle for articulation with the jaw
• 4 premaxillary teeth

Composite cladogram for Dyrosauridae (from Jouve et al. 2008 and Barbosa et al. 2008):

Dyrosauridae
|--Chenanisuchus
`--+--Phosphatosaurinae
   |  |--Sokotosuchus
   |  `--Phosphatosaurus
   `--Dyrosaurinae
      |--Dyrosaurus
      `--+--Arambourgisuchus
         |--Guarinisuchus
         `--+--Hyposaurus
            `--+--Congosaurus
               `--+--Atlantosuchus
                  `--Rhabdognathus
´
Dyrosauridae incertae sedis:
Tilemsisuchus

Analysis suggest that the closest relatives of dyrosaurids are Sarcosuchus and Terminonaris.

[edit] Palaeobiology

Dyrosaurids were a group of marine crocodiles.

[edit] References

• Jouve, S., Iarochène, M., Bouya, B. & Amaghzaz, M., (2005) A new dyrosaurid crocodyliform from the Palaeocene of Morocco and a phylogenetic analysis of Dyrosauridae. Acta Palaeontologica Polonica 50 (3): 581-594
• Babosa, J.A., Kellner, A.W.A. and Viana, M.S.S. (2008). New dyrosaurid crocodylomorph and evidences for faunal turnover at the K–P transition in Brazil. Proceedings of the Royal Sociey B: Biological Sciences: Firstcite
• Jouve, S., Bouya, B. and Amaghzaz, M. (2008). A long-snouted dyrosaurid (Crocodyliformes, Mesoeucrocodylia) from the Paleocene of Morocco: phylogenetic and palaeogeographic implications. Palaeontology 51 (2): 281-294

[edit] External links

• Jouve et al. (2005)
• Mikko's Phylogeny Archive Dyrosauridae page
• Paleopedia page on Dyrosauridae