Chimaerasuchidae ("

Chimera Chimera, Chimaera, or Chimaira (Greek for " she-goat") originally referred to: * Chimera (mythology), a fire-breathing monster of Ancient Lycia said to combine parts from multiple animals * Mount Chimaera, a fire-spewing region of Lycia or Cilicia ...

crocodiles") is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

mesoeucrocodylia Mesoeucrocodylia is the clade that includes Eusuchia and crocodyliforms formerly placed in the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day. Diagnosis It was long known that M ...

ns. It was erected as a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

in 2004 by Carvalho ''et al'' and included ''Chimaerasuchus'' from the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

and possibly also ''

Simosuchus ''Simosuchus'' (meaning "pug-nosed crocodile" in Greek, referring to the animal's blunt snout) is an extinct genus of notosuchian crocodylomorphs from the Late Cretaceous of Madagascar. It is named for its unusually short skull. Fully grown indi ...

'' from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

. The validity of the clade has been questioned in later studies that found the two genera to be more distantly related.

Phylogeny

In the phylogenetic analysis of Carvalho ''et al'', the family contained ''Chimaerasuchus'' and ''Simosuchus'', two

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

of small (~1 metre long), possibly herbivorous crocodyliforms from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

. Both had short-snouted heads with multicusped teeth. Carvalho ''et al'' placed Chimaerasuchidae within a new clade of mesoeucrocodylians called Gondwanasuchia. It was the sister taxon of Notosuchimorpha, another newly erected clade that contained

notosuchia Notosuchia is a suborder of primarily Gondwanan mesoeucrocodylian crocodylomorphs that lived during the Jurassic and Cretaceous. Some phylogenies recover Sebecosuchia as a clade within Notosuchia, others as a sister group (see below); if Sebecosu ...

sebecosuchia Sebecosuchia is an extinct group of mesoeucrocodylian crocodyliforms that includes the families Sebecidae and Baurusuchidae. The group was long thought to have first appeared in the Late Cretaceous with the baurusuchids and become extinct in the ...

ns, and

peirosaurid Peirosauridae is a Gondwanan family of mesoeucrocodylians that lived during the Cretaceous period. It was a clade of terrestrial crocodyliforms that evolved a rather dog-like form, and were terrestrial carnivores. It was phylogenetically defined ...

s. Below is a modified

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

from Carvalho ''et al'' (2004): The Carvalho ''et al.'' (2004) paper

phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

did not include

neosuchia Neosuchia is a clade within Mesoeucrocodylia that includes all modern extant crocodilians and their closest fossil relatives. It is defined as the most inclusive clade containing all crocodylomorphs more closely related to ''Crocodylus niloticus' ...

ns in the analysis. Neosuchians and notosuchians are the two major clades of mesoeucrocodylians. When neosuchians are included in analyses with ''Simosuchus'' and ''Chimaerasuchus'', the two genera do not appear as sister taxa (Pol 2003; Candeiro & Martinelli 2006). In fact '' Chimaerasuchus'' has been found to be the sister taxon of ''

Sphagesaurus ''Sphagesaurus'' is an extinct genus of sphagesaurid notosuchian crocodylomorph from the Late Cretaceous of southwest São Paulo, southern Brazil. Species and discovery ''Sphagesaurus'' was first described and named by Llewellyn Ivor Price in 1 ...

''. ''Sphagesaurus'' is often assigned its own family,

Sphagesauridae Sphagesauridae is a Gondwanan family of mesoeucrocodylians that lived during the Late Cretaceous. It was a clade of terrestrial crocodilians that evolved very mammal-like teeth and jaws.MARINHO, T.S. & CARVALHO, I.S. Revision of the Sphagesaurida ...

. If ''Chimaerasuchus'' belongs to Shagesauridae, Chimaerasuchidae would be a

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

of Sphagesauridae. This is because Sphagesauridae was named before Chimaerasuchidae, and under

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

rules, the oldest name has priority. In a recent contribution, Marinho & Carvalho (2007) did a revision of Sphagesauridae and noticed that ''Chimaerasuchus'' does not have any of the synapomorphies of this family that was originally erected by Kuhn (1968). In this new paper, the authors propose an emended diagnosis for the Sphagesauridae, pointing new synapomorphies for this taxon and propose that the Chimaerasuchidae would be a valid family in spite of the poor phylogenetic analysis of Carvalho ''et al.'' (2004) paper.

References

*Pol, D. (2003). New remains of ''Sphagesaurus huenei'' (Crocodylomorpha: Mesoeucrocodylia)from the Late Cretaceous of Brazil. ''Journal of Vertebrate Paleontology'' 23: 817-831 *Carvahlo, I.S., Ribeiro, L.C.B. and Avilla, L.S. (2004). ''Uberasuchus terrificus sp. nov.'', a new Crocodylomorpha from the Bauru Basin (Upper Cretaceous), Brazil. ''Gondwana Research'' 4: 975-1002 *Candeiro, C.R.A. & Martinelli, A.G. (2006). A review of paleogeographical and chronostratigraphical distribution of mesoeucrocodylian species from the upper Cretaceous beds from the Baurus (Brazil) and Neuquén (Argentina) groups, Southern South America. ''Journal of South American Earth Sciences'' 22:116-129 * Kuhn, O. 1968. Die Vortzeitlichen Krokodile. Verlag Oeben, Krailing, München, 124 p. * Marinho, T.S. & Carvalho, I.S. (2007). Revision of the Sphagesauridae KUHN, 1968 (Crocodyliformes, Mesoeucrocodylia). In: Carvalho, I.S.; Cassab, R.C.T.; Schwanke, C.; Carvalho, M.A.; Fernandes, A.C.S.; Rodrigues, M.A.; Carvalho, M.S.S.; Arai, M.; Oliveira, M.E.Q. (Eds.). Paleontologia: Cenários de Vida. 1 ed. Rio de Janeiro: Interciência, 1: 589-599.

External links

*Taxon Feedbac

*Science News
Ancient Crocrodile Chomped On Plants
*Nature "A Pugnosed Crocodyliform from the Late Cretaceous of Madagasca

{{Taxonbar, from=Q5099282 Early Cretaceous crocodylomorphs Terrestrial crocodylomorphs Late Cretaceous crocodylomorphs Early Cretaceous first appearances Late Cretaceous extinctions Prehistoric reptile families