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Clade
Subclade

Taxon
Taxon
Stagonolepididae
Nominal Author
Lydekker 1887
2nd Nominal Author
Taxon Status ACTIVE
Comments

As initially defined by Heckert and Lucas (2000:fig. 2), Stagonolepididae overlaps with Aetosauria, except that the former is node-based and the latter stem-based. Heckert and Lucas (2000) then erected a redundant taxon Aetosaurinae for the basal genus Aetosaurus. Benton (2004) more recently proposed a confusing definition that is both node- and stem-based, depending on the interpretation of its meaning.

The solution adopted here is to differentiate Stagonolepidididae from Aetosauria, using the former as a node-based taxon within a stem-based Aetosauria. In this way, Stagonolepidididae forms a node-stem triplet with Stagonolepidinae and Desmatosuchinae, to the exclusion of Aetosaurus (if current phylogentic analyses are reasonably correct; Heckert and Lucas 2000). Even though the original definition was also node-based, the active definition is a second-order revision, as it identifies a more restricted clade within Aetosauria.

Potential Synonomy
Stagonolepidae

Active Phylogenetic Definition
Active Definition
The least inclusive clade containing Stagonolepis robertsoni Agassiz 1844 and Desmatosuchus haplocerus (Cope 1892).
Shorthand
< Stagonolepis robertsoni and Desmatosuchus haplocerus.
Definitional Author
Sereno 2005
Definition Status checked
Definition Type NODE
Node-Stem Triplet NODE
Other Triplet Taxa
Stagonolepidinae, Desmatosuchinae
Specifiers
Specifier(s) A
Stagonolepis robertsoni
Specifier(s) B
Desmatosuchus haplocerus
Specifier(s) C
Qualifiers
+Taxon
-Taxon
Datum
Taxonomic Content
Publication Year Unknown
Unknown
Unknown
2005

Inactive Taxon Status
Rejection Criteria
Critique
 

Definitional History #1
Earliest Record
The last common ancestor (and all of its descendants) of Aetosaurus and Desmatosuchus.
Latest Record
Heckert and Lucas 2000:1544
Range (My)
Range (My)
Aetosaurus, Desmatosuchus
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Definitional History #2
Earliest Record
Those taxa stemming from the last common ancestor of Stagoolepis robertsoni and Aetosaurus ferratus and sharing a more recent common ancestor with those species than with Mystriosuchus planirostris, Ornithosuchus longidens, or Crocodylia.
Latest Record
Benton 2004:11
Range (My)
Range (My)
Stagonolepis robertosni, Aetosaurus ferratus, Mystriosuchus planirostris, Ornithosuchus longidens, Crocodylia
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