Taxonomic status of the specimens of<i>Archaeopteryx</i>

Senter, Phil; Robins, James H.

doi:10.1671/22

Cited by 20 publications

(11 citation statements)

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“…This would suggest that juvenile T. rex teeth have morphologies different enough from those of the adult animal to result in misclassifications. However, dental ontogeny in tyrannosaurids is very poorly understood (Smith, 2005), and contrary to Senter and Robins (2003), definitive juvenile T. rex dental material is almost completely lacking, so the hypothesis is currently impossible to test. The solution is obviously to incorporate juvenile dentitions into the standard data set used here.…”

Section: Discussionmentioning

confidence: 99%

Dental morphology and variation in theropod dinosaurs: Implications for the taxonomic identification of isolated teeth

2005

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Isolated theropod teeth are common Mesozoic fossils and would be an important data source for paleoecology biogeography if they could be reliably identified as having come from particular taxa. However, obtaining identifications is confounded by a paucity of easily identifiable characters. Here we discuss a quantitative methodology designed to provide defensible identifications of isolated teeth using Tyrannosaurus as a comparison taxon. We created a standard data set based as much as possible on teeth of known taxonomic affinity against which to compare isolated crowns. Tooth morphology was described using measured variables describing crown length, base length and width, and derived variables related to basal shape, squatness, mesial curve shape, apex location with respect to base, and denticle size. Crown curves were described by fitting the power function Y ϭ a ϩ bX 0.5 to coordinate data collected from lateral-view images of mesial curve profiles. The b value from these analyses provides a measure of curvature. Discriminant analyses compared isolated teeth of various taxonomic affinities against the standard. The analyses classified known Tyrannosaurus teeth with Tyrannosaurus and separated most teeth known not to be Tyrannosaurus from Tyrannosaurus. They had trouble correctly classifying teeth that were very similar to Tyrannosaurus and for which there were few data in the standard. However, the results indicate that expanding the standard should facilitate the identification of numerous types of isolated theropod teeth. 2005 Wiley-Liss, Inc. © 2005 Wiley-Liss, Inc. Key words: dinosauria; theropoda; teeth; morphometrics; taxonomy; discriminant analysisOne of the first steps in studying interactions among ancient organisms and their environments is identifying the taxa that comprised the ecosystem. Regrettably, this task can be quite complicated. For vertebrates, the difficulties in obtaining taxonomic identifications for isolated bones, and in some cases partial skeletons, have plagued researchers since the infancy of paleontology. The difficulties stem from a lack of recognized characters in many elements, degradation and loss of anatomical data through taphonomic processes, and the fact that withintaxon variation is poorly understood for most bones of most taxa. These issues confound study into most questions regarding ancient vertebrates, but the situation is acute where bone beds or attempts to generate paleopopulation census data are concerned (e.g., Dodson, 1971;

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Section: Discussionmentioning

confidence: 99%

Dental morphology and variation in theropod dinosaurs: Implications for the taxonomic identification of isolated teeth

2005

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“…The incomplete preservation of the Haarlem specimen (Fig. 1 ) precludes exact measurements for most long bones, which is most probably the reason why this specimen has not been included in previous evaluations of the proportions of Archaeopteryx [ 14 , 15 ]. Ostrom [ 16 ] and Wellnhofer [ 13 ] provided measurements for this specimen, but noted that most of them where either incomplete, or based on estimations.…”

Section: Methodsmentioning

confidence: 99%

Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs

Foth

Rauhut

2017

BMC Evol Biol

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Background Archaeopteryx is an iconic fossil that has long been pivotal for our understanding of the origin of birds. Remains of this important taxon have only been found in the Late Jurassic lithographic limestones of Bavaria, Germany. Twelve skeletal specimens are reported so far. Archaeopteryx was long the only pre-Cretaceous paravian theropod known, but recent discoveries from the Tiaojishan Formation, China, yielded a remarkable diversity of this clade, including the possibly oldest and most basal known clade of avialan, here named Anchiornithidae. However, Archaeopteryx remains the only Jurassic paravian theropod based on diagnostic material reported outside China.ResultsRe-examination of the incomplete Haarlem Archaeopteryx specimen did not find any diagnostic features of this genus. In contrast, the specimen markedly differs in proportions from other Archaeopteryx specimens and shares two distinct characters with anchiornithids. Phylogenetic analysis confirms it as the first anchiornithid recorded outside the Tiaojushan Formation of China, for which the new generic name Ostromia is proposed here.ConclusionsIn combination with a biogeographic analysis of coelurosaurian theropods and palaeogeographic and stratigraphic data, our results indicate an explosive radiation of maniraptoran coelurosaurs probably in isolation in eastern Asia in the late Middle Jurassic and a rapid, at least Laurasian dispersal of the different subclades in the Late Jurassic. Small body size and, possibly, a multiple origin of flight capabilities enhanced dispersal capabilities of paravian theropods and might thus have been crucial for their evolutionary success.Electronic supplementary materialThe online version of this article (10.1186/s12862-017-1076-y) contains supplementary material, which is available to authorized users.

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“…However, Houck et al [33] and Senter and Robins [48] argued that differences in proportions in nearly all specimens are explained by allometric developmental scaling. Other differences might be explained as sexual, or individual variation [2].…”

Section: Methodsmentioning

confidence: 99%

Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx

et al. 2009

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Background Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs.Methodology/Principal FindingsWe report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates.Conclusions/SignificanceThe unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.

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Taxonomic status of the specimens ofArchaeopteryx

Cited by 20 publications

References 9 publications

Dental morphology and variation in theropod dinosaurs: Implications for the taxonomic identification of isolated teeth

Dental morphology and variation in theropod dinosaurs: Implications for the taxonomic identification of isolated teeth

Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs

Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx

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