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Dinosaur papers: a new hope

I don't have any of these. Sadly. If somebody wants to throw them my way, I'd be forever grateful. :-)

Irmis, R.B., Parker, W.G. Nesbitt, S.J. and Liu, J. (2007). Early ornithischian dinosaurs: the Triassic record. Historical Biology 19(1): 3-22.

ABSTRACT: "Ornithischian dinosaurs are one of the most taxonomically diverse dinosaur clades during the Mesozoic, yet their origin and early diversification remain virtually unknown. In recent years, several new Triassic ornithischian taxa have been proposed, mostly based upon isolated teeth. New discoveries of skeletal material of some of these tooth taxa indicate that these teeth can no longer be assigned to the Ornithischia using unambiguous synapomorphies. The Triassic record of ornithischian dinosaurs now comprises only three probable occurrences: _Pisanosaurus_ and an unnamed heterodontosaurid from Argentina, and an unnamed specimen from the uppermost Triassic of South Africa. This revised Triassic record suggests that ornithischians were not very diverse or abundant through the Triassic, and there are large gaps in the Triassic ornithischian fossil record. Moreover, traditional living analogues for interpreting the feeding ecology of early ornithischians from their tooth morphology are generally inappropriate, and "herbivorous" archosaur teeth such as those found in early ornithischians are not necessarily diagnostic of herbivorous feeding."

Marsicano, C.A., Domnanovich, N.S., and Mancuso, A.C. (2007). Dinosaur origins: evidence from the footprint record. Historical Biology 19(1): 83-91.

ABSTRACT: "Triassic tracks and trackways assigned to dinosaur trackmakers or closest relatives have been mentioned from several Middle to the latest Triassic successions from both northern and southern Pangea. At present, the earliest gondwanan records are those from the Middle Triassic Los Rastros Formation in west-central Argentina. A reanalysis of Los Rastros ichnites at the Ischichuca area, including new material, has revealed the presence of a more diverse ichnofauna than previously suspected. The ichnocoenosis includes several tracks and trackways of bipeds with functionally tridactyl digitigrade pes, well developed claws, and a parasagittal posture of the hindlimbs. Previously, some large tridactyl footprints from the Ischichuca area were allied to theropod dinosaurs, although no synapomophies are preserved in the three-toed footprints that might discriminate among theropods, basal saurischians and basal ornithischian groups as their possible trackmakers. If the Ischichuca trackmakers are referred to a dinosaur taxon and/or to a close dinosaur sister-taxon, their presence in the Los Rastros levels suggests that derived dinosauriforms (including dinosaurs) had diverged and acquired their characteristic functionally tridactyl pes by at least the Middle Triassic, something that the body-fossil record has failed to document to date."

Pol, D. and Powell, J.W. (2007). Skull anatomy of _Mussaurus patagonicus_ (Dinosauria: Sauropodomorpha) from the Late Triassic of Patagonia. Historical Biology 19(1): 125-144.

ABSTRACT: "The skull anatomy of _Mussaurus patagonicus_ from the Upper Triassic Laguna Colorada Formation is described based on a revision of the type material and several recently found specimens. The studied material include two distinct size classes of individuals. The type material consists of extremely young individuals whereas the new specimens are interpreted as juvenile or subadult individuals. The latter are significantly larger, having a skull approximately three times longer than the type material. The skull anatomy of this taxon shows derived characters shared with some basal sauropodomorphs and eusauropods, which are absent in other basal sauropodomorphs (e.g. _Thecodontosaurus_, _Plateosaurus_). These include the presence of an extension of the infratemporal fenestra ventral to the orbit, dorsal and anterior rami of quadratojugal subperpendicular to each other, dorsoventral expansion of dentary at mandibular symphysis, slightly procumbent teeth with broad serrations restricted to the apical region (absent in some teeth). Differences among the studied specimens helps to understand the early ontogenetic changes occurring in this basal sauropodomorph, revealing major changes in the rostral and temporal regions."

Sereno, P.C. (2007). The phylogenetic relationships of early dinosaurs: a comparative report. Historical Biology 19(1): 145-155.

ABSTRACT: "Surprising new anatomical information has come to light for the early dinosaurs _Eoraptor lunensis_ and _Herrerasaurus ischigualastensis_. _Eoraptor_ has a mid mandibular jaw joint, and _Herrerasaurus_ has a promaxillary fenestra at the anterior end of the antorbital fossa. Initial cladistic interpretation placed _Herrerasaurus_ outside Dinosauria. Since then, _Eoraptor_ and _Herrerasaurus_ have been placed at the base of Saurischia or within Theropoda in two large-scale quantitative analyses. A comparative approach is taken here to show, first, that character choice is a major factor behind differing results; only half of the character data critical for each interpretation is incorporated into the opposing analysis. In that shared portion of data, furthermore, nearly 40 percent of character state scores vary for identical, or comparable, ingroup taxa. Resolving these conflictive interpretations is clearly where future progress will be made in understanding early dinosaur phylogenesis."

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