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Clade
Subclade

Taxon
Taxon
Peirosauridae
Nominal Author
Gasparini 1982
2nd Nominal Author
Taxon Status ACTIVE
Comments

There is much confusion and little consensus regarding Peirosauridae. Genus and species diagnoses do not clearly specifiy apomorphies, and taxonomic decisions have been based on overall snout proportions (longirostrine versus platyrostrine). These have provided a false guide to alpha taxonomy as well as suprageneric relationships, which has been compounded recently by the erection of several poorly-supported higher taxa based on Peirosaurus (Peirosauriformes, Peirosauromorpha; Carvalho et al. 2004).

Price (1950) described and figured fragmentary cranial and postcranial bones of a new taxon from the MarÝlia Formation of southern Brazil. Although fragmentarry, the material included a cmplete premaxilla that exhibits several diagnostic features that Price included in his diagnosis. These include the anteriorly projecting internarial bar, the unusual narial fossa, etc. Gasparini et al. (1991), in contrast, dropped these features from the diagnosis of Peirosauridae and, additionally, referred a specimen from Argentina to the species Peirosaurus torminni (whcih they mispelled “tormini”) that does not exhibit or preserved these features and that clearly has a broader premaxilla. This specimen may be closely related, but it cannot be referred to the species P. torminni; Gasparini et al. (1991) do not provide any basis for their generic and specific assignment. They describe and refer a new taxon, Lomasuchus palpebrosus, to the Peirosauridae, but this taxon does not preserve the anterior and most characteristic end of the premaxilla. Again, it may be closely related to Peirosaurus torminni, but critical evidence related to this is missing.

Subsequently, Larsson and Gado (2000) described Stolokrosuchus lapparenti from the Aptian-Albian-age Elrhaz Formation of Niger, placing it within Peirosauridae. Although not well figured, the premaxilla bears a striking resemblance to Peirosaurus torminni and bears all of its apomorphies. Lapparent de Broin (2002), apparently influenced by the longirostrine condition of Stolokrosuchus lapparenti, removed it from Peirosauridae and placed it in a new family with a new Algerian longirostrine form, Elosuchus cherifiensis, which does not bear any of the apomorphies of Peirosaurus torminni. For example, in Elosuchus cherifiensis there is no anteriorly projecting internarial bar or unusual external narial fossa.

Recently Carvalho et al. (2004) described a complete skull from the type locality of Peirosaurus torminni as Uberabasuchus terrificus. The premaxilla and short globular posterior maxillary teeth appear to be identical to that of the holotype of Peirosaurus torminni. Carvalho et al. (2004) do not differentiate the two with any tangible evidence, and so U. terrificus is here regared as a junior synonym of P. torminni.

Carvalho et al. (2004) recently defined Peirosauridae with a node-based definition using Peirosaurus and Lomasuchinae, a group that in their analysis included Lomasuchus palpebrosus, Mahajangasuchus insignis and Uberabasuchus terrificus. The active definition, in contrast, is a second-order revision that establishes a stem-based group anchored on the nominotypical species Peirosaurus torminni that excludes the representative species of clades that have not been placed alongside Peirosaurus or within Peirosauridae. Peirosauridae is better accommodated with a stem-based definition that does not specifiy the internal contents of the clade, which has varied among recent analyses (e.g. Buckley et al. 2000, Larsson and Gado 2000, Sereno et al. 2003) and which has included taxa that are poorly known. The form of the premaxilla and the configuration of the external nares, incisive foramen, and premaxillary palate are distinctive features of this clade. The position of Peirosauridae within Notosuchia or elsewhere within Metasuchia remain unresolved.

Potential Synonomy

Active Phylogenetic Definition
Active Definition
The most inclusive clade containing Peirosaurus torminni Price 1955 but not Araripesuchus gomesii Price 1959, Simosuchus clarki Buckley et al. 2000, Notosuchus terrestris Woodward 1896, Baurusuchus pachecoi Price 1945, Crocodylus niloticus (Laurenti 1768).
Shorthand
> Peirosaurus torminni but not Araripesuchus gomesii, Simosuchus clarki, Notosuchus terrestris, Baurusuchus pachecoi, Crocodylus niloticus.
Definitional Author
Sereno 2005
Definition Status checked
Definition Type STEM
Node-Stem Triplet NO
Other Triplet Taxa
Specifiers
Specifier(s) A
Pierosaurus torminni
Specifier(s) B
Specifier(s) C
Araripesuchus gomesii, Simosuchus clarki, Notosuchus terrestris, Baurusuchus pachecoi, Crocody
Qualifiers
+Taxon
-Taxon
Datum
Taxonomic Content
Publication Year Unknown
Unknown
Unknown
2005

Inactive Taxon Status
Rejection Criteria
Critique
 

Definitional History #1
Earliest Record
The most reccent common ancestor of Peirosaurus and Lomasuchinae and all of their descendants.
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Carvalho et al. 2004:995
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Pierosaurus, Lomasuchinae
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