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A new paper is out online that you'll find shocking: Müller RT, Garcia MS. 2020. A paraphyletic ‘Silesauridae’ as an alternative hypothesis for the initial radiation of ornithischian dinosaurs. Biol. Lett.16:20200417. http://dx.doi.org/10.1098/rsbl.2020.0417 I remember that several Late Triassic animals erected upon teeth (Crosbysaurus, Galtonia, Krzyzanowskisaurus, Lucianosaurus, Pekinosaurus, Protecovasaurus, Revueltosaurus, and Tecovasaurus) were once classified within Ornithischia because the type teeth of those taxa are similar to those of ornithischians (some early sauropodomorphs have leaf-shaped teeth, too), but Revueltosaurus was later reclassified as an extinct relative of alligators and crocodiles based on complete material, and Galtonia and Pekinosaurus were also recognized as suchians closely related to Revueltosaurus, meaning that other putative Triassic ornithischian taxa from the American Southwest were placed in Archosauriformes incertae sedis by Parker et al. (2005) and Irmis et al. (2007) due to the presence of triangular leaf-shaped teeth being convergent among ornithischian dinosaurs and some non-dinosaurian clades. The hyper-sparse record of Triassic Ornithischia left people scratching their heads to explain the paucity of Triassic ornithischian fossils, with some speculating that ornithischians did not diversify until the Early Jurassic; the fact that Pisanosaurus combines some craniodental traits of Ornithischia more advanced than those of Lesothosaurus and the postcranial traits of basal dinosauriforms complicated matters further, because this mosaic of morphological features threatened the status of Pisanosaurus as the oldest ornithischian. Agnolin and Rozadilla (2018) tidied up matters by concluding that Pisanosaurus is a silesaurid that evolves craniodental features convergent with those of advanced ornithischians. The new paper by Muller and Garcia (2020) has a pretty novel hypothesis to explain the virtually non-existence of Ornithischia in Triassic deposits. It shockingly recovers Silesauridae as paraphyletic with respect to traditional Ornithischia (containing Genasauria and Eocursor), suggesting that the earliest relatives of Ornithischia evolved a purely faunivorous diet, given that Asilisaurus from Tanzania has sub-triangular crowns and a constricted root and dentaries with a beak-like anterior tip. For instance, Lewisuchus is recovered a more primitive than Soumyasaurus and Asilisaurus. Since Pisanosaurus has a mosaic of ornithischian-like features and postcranial traits usually seen in non-dinosaurian dinosauromorphs, it may be surmised that the earliest dinosaurs had some postcranial features similar to those of lagerpetids and Lagosuchus. Of interesting note is the fact that Technosaurus (named for Texas Tech University where the holotype is stored) was once considered a 'fabrosaurid' ornitischian before it was classified as a silesaurid, so the placement of all silesaurs as closely related to Ornithischia and recovery of Pisanosaurus as sister to Ornithischia means that the peculiar morphology of Pisanosaurus renders silesaurs more closely related to ornithischians. Randall B. Irmis, William G. Parker, Sterling J. Nesbitt & Jun Liu (2007) Early ornithischian dinosaurs: the Triassic record. Historical Biology, 19:1, 3-22, DOI: 10.1080/08912960600719988 Parker, W. G., Irmis, R. B., Nesbitt, S. J., Martz, J. W., & Browne, L. S. (2005). The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs. Proceedings. Biological sciences, 272(1566): 963–969. https://doi.org/10.1098/rspb.2004.3047
Fruitbat posted a topic in DocumentsThese are a few of the pdf files (and a few Microsoft Word documents) that I've accumulated in my web browsing. MOST of these are hyperlinked to their source. If you want one that is not hyperlinked or if the link isn't working, e-mail me at firstname.lastname@example.org and I'll be happy to send it to you. Please note that this list will be updated continuously as I find more available resources. All of these files are freely available on the Internet so there should be no copyright issues. Articles with author names in RED are new additions since August 4, 2018. Basal Archosauromorphs Martinelli, A.G., et al. (2016). The oldest archosauromorph from South America: postcranial remains from the Guadalupian (mid-Permian) Rio do Rasto Formation (Parana Basin), southern Brazil. Historical Biology, 2016. Stocker, M.R., et al. (2016). A Dome-Headed Stem Archosaur Exemplifies Convergence among Dinosaurs and Their Distant Relatives. Current Biology, 26. Family Lagerpetidae Arcucci, A. (1986). New Materials and Reinterpretation of Lagerpeton chanarensis Romer (Thecodontia, Lagerpetonidae Nov.) from the Middle Triassic of La Rioja, Argentina. Ameghiniana, 23(3-4). Martinez, R.N., et al. (2016). A Norian Lagerpetid Dinosauromorph from the Quebrada Del Barro Formation, Northwestern Argentina. Ameghiniana, Vol.53(1). Müller, R.T., M.C. Langer and S. Dias-da-Silva (2018). Ingroup relationships of Lagerpetidae (Avemetatarsalia: Dinosauromorpha): a further phylogenetic investigation on the understanding of dinosaur relatives. Zootaxa, 4392(1). Nesbitt, S.J., et al. (2009). Hindlimb Osteology and Distribution of Basal Dinosauromorphs from the Late Triassic of North America. Journal of Vertebrate Paleontology, 29(2). Sarigül, V. (2016). New basal dinosauromorph records from the Dockum Group of Texas, USA. Palaeontologia Electronica, 19.2.21A. Family Silesauridae Bittencourt, J.S., et al. (2014). Osteology of the Middle Triassic archosaur Lewisuchus admixtus Romer (Chañares Formation, Argentina), its inclusivity, and relationships amongst early dinosauromorphs. Journal of Systematic Paleontology, Vol.0, Number 0. Dzik, J. (2003). A Beaked Herbivorous Archosaur With Dinosaur Affinities from the Early Late Triassic of Poland. Journal of Vertebrate Paleontology, 23(3). Ezcurra, M.D. (2006). A review of the systematic position of the dinosauriform archosaur Eucoelophysis baldwini Sullivan&Lucas, 1999, from the Upper Triassic of New Mexico, USA. Geodiversitas, 28(4). Kammerer, C.F., S.J. Nesbitt and N.H. Shubin (2012). The first silesaurid dinosauriform from the Late Triassic of Morocco. Acta Palaeontologica Polonica, 57(2). Kubo, T. and M.O. Kubo (2014). Dental microwear of a Late Triassic dinosauriform, Silesaurus opolensis. Acta Palaeontologica Polonica, 59(2). Langer, M.C. and J. Ferigolo (2013). The Late Triassic dinosauromorph Sacisaurus agudoensis (Caturrita Formation; Rio Grande do Sul, Brazil): anatomy and affinities. In: Anatomy, Phylogeny and Palaeobiology of Early Archosaurs and their Kin. Nesbitt, S.J., J.G. Desojo and R.B. Irmis (eds.), Geological Society, London, Special Publications, 379. Nesbitt, S.J., et al. (2010). Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira. Nature (Letters), Vol.464/4. Piechowski, R. and J. Dzik (2010). The Axial Skeleton of Silesaurus opolensis. Journal of Vertebrate Paleontology, 30(4). Other Non-Dinosaurian Dinosauriforms Benton, M.J. and A.D. Walker (2011). Saltopus, a dinosauriform from the Upper Triassic of Scotland. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 101. Ezcurra, M.D. and R.N. Martinez (2016). Dinosaur precursors and early dinosaurs from Argentina. In: Historia Evolutia y Paleobiogeografia de los Vertebradps de America del Sur. Agnolin, F.L., et al. (eds.), Contribuciones del MACN, 6. Fechner, R. (2009). Morphofunctional Evolution of the Pelvic Girdle and Hindlimb of Dinosauromorpha on the Lineage to Sauropoda. Ph.D. Dissertation - Ludwigs Maximilians Universitat, Munich. Irmis, R.B., et al. (2007). A Late Triassic Dinosauromorph Assemblage from New Mexico and the Rise of Dinosaurs. Science, Vol.317. Langer, M.C., et al. (2013). Non-dinosaurian Dinosauromorpha. Geological Society, London, Special Publications, published on-line. Müller, R,T., et al. (2014). New dinosauriform (Ornithodira, Dinosauromorpha) record from the Upper Triassic of Southern Brazil. Paleontological Research, Vol.18, Number 2. Nesbitt, S.J., R.J. Butler and D.J. Gower (2013). A New Archosauriform (Reptilia: Diapsida) from the Manda Beds (Middle Triassic) of Southwestern Tanzania. PLoS ONE, 8(9). Nesbitt, S.J., et al. (2013). The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania. Biology Letters, 9.