title: Revised phylogenetic analysis of the Aetosauria (Archosauria: Pseudosuchia); assessing the effects of incongruent morphological character sets.
abstract: Aetosauria is an early-diverging clade of pseudosuchians (crocodile-line archosaurs) that had a global distribution and high species diversity as a key component of various Late Triassic terrestrial faunas. It is one of only two Late Triassic clades of large herbivorous archosaurs, and thus served a critical ecological role. Nonetheless, aetosaur phylogenetic relationships are still poorly understood, owing to an overreliance on osteoderm characters, which are often poorly constructed and suspected to be highly homoplastic. A new phylogenetic analysis of the Aetosauria, comprising 27 taxa and 83 characters, includes more than 40 new characters that focus on better sampling the cranial and endoskeletal regions, and represents the most comprenhensive phylogeny of the clade to date. Parsimony analysis recovered three most parsimonious trees; the strict consensus of these trees finds an Aetosauria that is divided into two main clades: Desmatosuchia, which includes the Desmatosuchinae and the Stagonolepidinae, and Aetosaurinae, which includes the Typothoracinae. As defined Desmatosuchinae now contains Neoaetosauroides engaeus and several taxa that were previously referred to the genus Stagonolepis, and a new clade, Desmatosuchini, is erected for taxa more closely related to Desmatosuchus. Overall support for some clades is still weak, and Partitioned Bremer Support (PBS) is applied for the first time to a strictly morphological dataset demonstrating that this weak support is in part because of conflict in the phylogenetic signals of cranial versus postcranial characters. PBS helps identify homoplasy among characters from various body regions, presumably the result of convergent evolution within discrete anatomical modules. It is likely that at least some of this character conflict results from different body regions evolving at different rates, which may have been under different selective pressures.
authors.affiliation: Division of Resource Management, Petrified Forest National Park, Arizona, United States; Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States.
authors.forename: William G
authors.initials: WG
authors.lastname: Parker
keywords: Aetosauria; Chinle Formation; Partitioned Bremer Support; Phylogeny; Pseudosuchia; Triassic
references.citation: Mol Phylogenet Evol. 1998 Jun;9(3):427-36
references.pmid: 9667991
references.citation: Anat Rec (Hoboken). 2014 Feb;297(2):240-60
references.pmid: 24376217
references.citation: Nature. 2008 Jan 31;451(7178):510
references.pmid: 18235465
references.citation: Trends Ecol Evol. 1996 Apr;11(4):152-8
references.pmid: 21237790
references.citation: Mol Biol Evol. 1997 Jul;14(7):733-40
references.pmid: 9214746
references.citation: Proc Biol Sci. 2005 May 7;272(1566):963-9
references.pmid: 16024353
references.citation: Syst Biol. 1997 Dec;46(4):751-64
references.pmid: 11975340
references.citation: J Evol Biol. 2009 Jun;22(6):1308-16
references.pmid: 19490385
references.citation: Proc Natl Acad Sci U S A. 1996 Jul 9;93(14):7085-90
references.pmid: 8692949
references.citation: Syst Biol. 2008 Apr;57(2):185-201
references.pmid: 18404577
references.citation: Syst Biol. 2003 Jun;52(3):403-22
references.pmid: 12775528
references.citation: J Hered. 1992 May-Jun;83(3):189-95
references.pmid: 1624764
references.citation: BMC Evol Biol. 2014 Jun 10;14:128
references.pmid: 24916124
references.citation: Cladistics. 2006 Aug;22(4):378-386
references.pmid: 34892868
references.citation: Cladistics. 2002 Aug;18(4):436-444
references.pmid: 34911216
references.citation: Syst Biol. 2005 Aug;54(4):530-47
references.pmid: 16085573
references.citation: Science. 2011 Jan 14;331(6014):206-10
references.pmid: 21233386
references.citation: Syst Biol. 1998 Dec;47(4):625-40
references.pmid: 12066307
references.citation: J Morphol. 2008 Apr;269(4):398-422
references.pmid: 17960802
references.citation: Folia Primatol (Basel). 1999;70(3):125-35
references.pmid: 10394061
references.citation: Syst Biol. 1997 Dec;46(4):654-73
references.pmid: 11975337
references.citation: Proc Natl Acad Sci U S A. 2014 Jun 3;111(22):7958-63
references.pmid: 24843149
references.citation: Mol Biol Evol. 2001 Apr;18(4):676-80
references.pmid: 11264420
references.citation: Anat Rec (Hoboken). 2014 Jun;297(6):1022-46
references.pmid: 24421153
references.citation: Syst Biol. 1998 Mar;47(1):3-8
references.pmid: 12064238
references.citation: Syst Biol. 1998 Dec;47(4):568-81
references.pmid: 12066302
references.citation: Syst Biol. 2005 Aug;54(4):595-619
references.pmid: 16109704
references.citation: Science. 1993 May 7;260(5109):794-7
references.pmid: 17746113
references.citation: Syst Biol. 2003 Apr;52(2):239-52
references.pmid: 12746149
references.citation: Science. 2007 Jul 20;317(5836):358-61
references.pmid: 17641198
references.citation: Cladistics. 1988 Jun;4(2):105-209
references.pmid: 34949076
references.citation: Zootaxa. 2014 Feb 11;3764:240-78
references.pmid: 24870635
references.citation: Science. 1994 Apr 29;264(5159):671-7
references.pmid: 8171318
references.citation: PLoS One. 2014 Feb 27;9(2):e89165
references.pmid: 24586565