Browsing by Author "Chiappe, Luis M."
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Item Anatomy and systematics of the Confuciusornithidae (Theropoda, Aves) from the late Mesozoic of northeastern China. Bulletin of the AMNH ; no. 242([New York] : American Museum of Natural History, 1999) Chiappe, Luis M.; Ji, Shu-An.; Ji, Qiang.; Norell, Mark A."The osteology and plumage of Confuciusornis sanctus and Changchengornis hengdaoziensis from the Chaomidianzi Formation (previously referred to as the lower section of the Yixian Formation) of western Liaoning Province (China) are described in detail. Confusiusornis sanctus and Changchengornis hengdaoziensis have toothless, beaked skulls (the tomial crest is straight in the former species and strongly curved in the latter) and retain the dorsal portion of the nasal process of the maxilla. The skull of Confuciusornis sanctus is of typical diapsid plan. It possesses a triradiate postorbital that with the squamosal forms a complete supratemporal arcade. Furthermore, a robust jugal-postorbital contact completely separates the infratemporal fenestra from the orbit. Although the postorbital region is not preserved in Changchengornis hengdaoziensis, it likely resembles that of Confuciusornis sanctus. Both species have abbreviated tails with long pygostyles, not the long, bony tail originally reconstructed in Confuciusornis sanctus. Scapulae and coracoids are fused to form scapulocorcoids. The coracoids are strutlike but much shorter than the scapulae. The furculae are robust and boomerang shaped. The sterna are long and nearly flat. The complete basket of gastralia follows the sternum caudally. The wing elements are short, and proportions among individual bones are primitive in that the hand is longer than either the humerus or the ulna and the ulna is shorter than the humerus. The pelvis is opisthopubic. The postacetabular wing of the ilium is much shorter than the preacetabular wing. Differences in plumage, namely the presence or absence of two very long tail feathers, are observed among several well-preserved specimens of Confuciusornis sanctus. This difference is likely the expression of sexual dimorphism, although other biological attributes known for extant populations (e.g. differential molting, correlation between sexual maturity and ornamental plumage) indicate that alternative explanations may also account for the observed plumage variation among specimens of Confusiusornis sanctus. Given the latest Jurassic-earliest Cretaceous age of the Chaomidianzi Formation, Confusiusornis sanctus and Changchengornis hengdaoziensis are surely among the oldest know birds after the Early Tithonian Archaeopteryx lithographica. Confusiusornis sanctus and Changchengornis hengdaoziensis thus furnish the earliest record of beaked birds. The fully diapsid skull of Confusiusornis sanctus, and presumably of Changchengornis hengdaoziensis, and the absence of a bending zone on the base of the snout suggest that earlier interpretations of the skull of Confusiusornis sanctus as prokinetic are incorrect. Confuciusornis sanctus probably had very limited cranial kinetic capabilities, if any. Optimization of the postorbital-jugal contact, a character intimately correlated with intracranial kinesis, in a phylogeny of basal avians indicates that the essentially akinetic condition of the skull of Confuciusornis sanctus is a reversal derived from forms possessing kinetic properties. Recent recognition of two additional species of Confuciusornis - Confuciusornis chuonzhous and Confuciusornis suniae - are based on anatomical misinterpretations. Thus, Confuciusornis suniae and Confuciusornis chuonzhous are regarded as junior synonyms of Confuciusornis sanctus. Confuciusornis sanctus is the sister-taxon of Changchengornis hengdaoziensis, and both are placed within the Confuciusornithidae. Some of the synapomorphies supporting this grouping include the presence of edentolous jaws, a rostrally forked mandibular symphysis, a reduced claw of manual digit II, and a V-shaped caudal margin of the sternum. The Confuciusornithidae is considered to be the sister-group of a clade composed of the Enantiornithomorpha and the Ornithuromorpha. This phylogenetic interpretation is far more parsimonious than previous systematic hypotheses placing the Confuciusornithidae as either within the Enantiornithes or as its sister-group. Purported climbing specializations of Confuciusornis sanctus are evaluated in light of the available anatomical evidence. We conclude that both Confuciusornis sanctus and Changchengornis hengdaoziensis were ill suited for tree climbing. The foot of Changchengornis hengdaoziensis, however, suggests a greater grasping ability than that of Confuciusornis sanctus. It is argued that both Confuciusornis sanctus and Changchengornis hengdaoziensis were able to fly and take off from the ground. The remarkable concentration of specimens of Confuciusornis sanctus from a relatively small quarry near the village of Sihetun (Liaoning Province) suggests several events of mass mortality and, perhaps, a gregarious behavior"--P. 3.Item An embryonic oviraptorid (Dinosauria, Theropoda) from the Upper Cretaceous of Mongolia. American Museum novitates ; no. 3315(New York, NY : American Museum of Natural History, 2001) Norell, Mark.; Clark, James Matthew, 1956-; Chiappe, Luis M.; Mongolian-American Museum Paleontological Project.; Mongolyn Shinzhlėkh Ukhaany Akademi.An embryonic oviraptorid skeleton is described within an egg from the late Cretaceous Djadokh[t]a Formation of Ukhaa Tolgod, Mongolia. The specimen comprises the ventral part of the skull and most of the mandible, a poorly preserved axial skeleton missing most of the tail, and portions of the forelimbs, shoulder girdles, pelvis, and hindlimbs. The skull is readily referable to the theropod dinosaur clade Oviraptoridae on the basis of several skull specializations (edentulous, vertically oriented premaxilla, a sinusoidally shaped lower jaw, and an unusual articulation of the vomer and premaxilla), and the postcranial skeleton is consistent with this identification. The egg is equivalent in overall shape and microstructure to those found beneath several oviraptorid skeletons recovered from the same formation. The skeleton is well ossified and, in comparison with ossification patterns in living Aves, the evidence suggests that this species was closer to the precocial end of the precocial-altricial spectrum of developmental patterns.Item Enantiornithine (Aves) tarsometatarsi from the Cretaceous Lecho Formation of northwestern Argentina. American Museum novitates ; no. 3083(New York, N.Y. : American Museum of Natural History, 1993) Chiappe, Luis M.Item Juvenile birds from the early Cretaceous of China : implications for enantiornithine ontogeny ; American Museum novitates, no. 3594(New York, NY : American Museum of Natural History, 2007) Chiappe, Luis M.; Ji, Shu'an.; Ji, Qiang.Mesozoic remains of embryonic and early juvenile birds are rare. To date, a handful of in ovo embryos and early juveniles of enantiornithines from the early Cretaceous of China and Spain and the late Cretaceous of Mongolia and Argentina have comprised the entire published record of perinatal ontogenetic stages of Mesozoic birds. We report on the skeletal morphology of three nearly complete early juvenile avians from the renowned early Cretaceous Yixian Formation of Liaoning Province in northeastern China. Evidence of the immaturity of these specimens is expressed in the intense grooving and pitting of the periosteal surfaces, the disproportionately small size of the sterna, and the relative size of the skull and orbits. Size notwithstanding, anatomical differences between these three specimens are minimal, leaving no basis for discriminating them into separate taxa. Numerous osteological synapomorphies indicate that they are euenantiornithine birds, the most diverse clade of Enantiornithes, but their identification as members of a particular euenantiornithine taxon remains unclear. Their early ontogenetic stage, however, provides important information about the postnatal development of this specious clade of Cretaceous birds. The presence of pennaceous wing feathers suggests that fledging occurred very early in ontogeny, thus supporting a precocial or highly precocial strategy for enantiornithine hatchlings. The morphology of these new early-stage juveniles is also significant in that they allow a better understanding of the homologies of several avian compound bones because the components of these skeletal compounds are preserved prior to their coossification. The general morphology of the wrist and ankle of these juveniles highlights once again the striking similarity between nonavian theropods and early birds.Item A new carinate bird from the late Cretaceous of Patagonia (Argentina). American Museum novitates ; no. 3323(New York, NY : American Museum of Natural History, 2001) Clarke, Julia A.; Chiappe, Luis M.A new bird from the late Cretaceous of Patagonia (Argentina), known from associated wing elements, is described and its phylogenetic position evaluated. Fossil taxa as well as representatives of species of extant birds sampled from lineages considered to be basal within the crown clade were included in a cladistic analysis of 72 characters primarily from the thoracic limb. Based on the results of the phylogenetic analysis and identification of autapomorphies in the specimen, we name a new taxon Limenavis patagonica. Limenavis patagonica is identified as closer to the crown clade than Enantiornithes by the presence of three unambiguous synapomorphies: a fossa (sometimes with two distinguishable subparts) on the dorsal, distalmost extremity of the humerus; distal fusion of metacarpals II and III; and an extensor process on metacarpal I. It is placed closer to the crown clade than Ichthyornis, and, thus, unambiguously as a carinate (see Methods for terminology), by two further synapomorphies: the abruptly truncate contact of the dorsal trochlear surface of the ulna with the ulnar shaft and the loss of a tubercle adjacent to the tendinal groove on the distal ulna. Finally, Limenavis patagonica is diagnosed by three autapomorphies: the attachment of the pars ulnaris of the trochlea humeroulnaris on the proximal ulna developed as a pit-shaped fossa; the location of the pisiform process with its proximal surface at approximately the same level as the proximal surface of metacarpal I; and a scar of the ligamentum collaterale ventrale of the ulna proximodistally elongate and extending down the caudal margin of the brachial impression. Limenavis patagonica is placed just outside the avian crown clade. The shortest tree with the new taxon as part of the crown clade is five steps longer than the most parsimonious topology.Item A new skull of Gobipteryx minuta (Aves, Enantiornithes) from the Cretaceous of the Gobi Desert. American Museum novitates ; no. 3346(New York, NY : American Museum of Natural History, 2001) Chiappe, Luis M.; Norell, Mark.; Clark, James Matthew, 1956-; Mongolian-American Museum Paleontological Project.; Mongolyn Shinzhlėkh Ukhaany Akademi.We describe an exquisitely preserved new skull of a bird from the late Cretaceous sandstones of Ukhaa Tolgod, southern Mongolia. Derived similarities shared between this skull and the holotype of Gobipteryx minuta, also from the late Cretaceous of the Gobi Desert, support the assignment of the new cranial material to this avian taxon. The new skull also proves indistinguishable from that of the enantiornithine Nanantius valifanovi from the late Cretaceous of Mongolia. The identification of the new skull as that of Gobipteryx minuta and its correspondence to that of Nanantius valifanovi indicate that the latter taxon is a junior synonym of Gobipteryx minuta. This taxonomic conclusion is crucial for understanding the phylogenetic relationships of Gobipteryx minuta because the undoubtedly enantiornithine postcranial morphology of Nanantius valifanovi provides the first uncontroversial evidence of the enantiornithine relationship of Gobipteryx minuta. The new skull from Ukhaa Tolgod and our reinterpretation of cranial aspects of the previously published material of Gobipteryx minuta and Nanantius valifanovi permit an accurate reconstruction of the palate of this enantiornithine bird, thus adding significant data for understanding the poorly known palatal structure of Mesozoic birds.Item The osteology of Concornis lacustris (Aves, Enantiornithes) from the Lower Cretaceous of Spain and a reexamination of its phylogenetic relationships. American Museum novitates ; no. 3133(New York, N.Y. : American Museum of Natural History, 1995) Sanz, José L.; Chiappe, Luis M.; Buscalioni, Angela D.Item An oviraptorid skeleton from the late Cretaceous of Ukhaa Tolgod, Mongolia, preserved in an avianlike brooding position over an oviraptorid nest. American Museum novitates ; no. 3265(New York, NY : American Museum of Natural History, 1999) Clark, James Matthew, 1956-; Norell, Mark.; Chiappe, Luis M.; Mongolian-American Museum Paleontological Project.; Mongolyn Shinzhlėkh Ukhaany Akademi."The articulated postcranial skeleton of an oviraptorid dinosaur (Theropoda, Coelurosauria) from the late Cretaceous Djadokhta Formation of Ukhaa Tolgod, Mongolia, is preserved overlying a nest. The eggs are similar in size, shape, and ornamentation to another egg from this locality in which an oviraptorid embryo is preserved, suggesting that the nest is of the same species as the adult skeleton overlying it and was parented by the adult. The lack of a skull precludes specific identification, but in several features the specimen is more similar to Oviraptor than to other oviraptorids. The ventral part of the thorax is exceptionally well preserved and provides evidence for other avian features that were previously unreported in oviraptorids, including the articulation of the first three thoracic ribs with the costal margin of the sternum and the presence of a single, ossified ventral segment in each rib as well as ossified uncinate processes associated with the thoracic ribs. Remnants of keratinous sheaths are preserved with four of the manal claws, and the bony and keratinous claws were as strongly curved as the manal claws of Archaeopteryx and the pedal claws of modern climbing birds. The skeleton is positioned over the center of the nest, with its limbs arranged symmetrically on either side and its arms spread out around the nest perimeter. This is one of four known oviraptorid skeletons preserved on nests of this type of egg, comprising 23.5% of the 17 oviraptorid skeletons collected from the Djadokhta Formation before 1996. The lack of disturbance to the nest and skeleton indicate that the specimen is preserved in the position in which the adult died. Its posture is the same as that commonly taken only by birds among tetrapods that brood their nest, and its close proximity to the eggs indicates that the nest was not covered, indicating that the behavior of sitting on open nests in this posture evolved before the most recent common ancestor of modern birds"--P. [1]-2.Item Pennaraptoran theropod dinosaurs : past progress and new frontiers. (Bulletin of the American Museum of Natural History, no. 440)(American Museum of Natural History., 2020-08-21) Pittman, Michael, 1985-; Xu, Xing, 1969-; O'Connor, Jingmai.; Field, Daniel J.; Turner, Alan H. (Alan Hamilton); Ma, Waisum.; Makovicky, Peter J.; Tse, Edison.; Norell, Mark.; Pei, Rui.; Pol, Diego.; Goloboff, Pablo A.; Ding, Anyang.; Upchurch, Paul.; Berv, Jacob S.; Hsiang, Allison Y.; Landis, Michael J.; Dornburg, Alex.; Nebreda, Sergio M.; Navalón, Guillermo.; Menéndez, Iris.; Sigurdsen, Trond.; Chiappe, Luis M.; Marugán-Lobón, Jesús.; Wang, Shuo.; Stiegler, Josef.; Wu, Ping.; Zhong, Zhengming.; Lautenschlager, Stephan.; Meade, Luke E.; Roy, Arindam.; Rogers, Christopher S.; Clements, Thomas.; Habimana, Olivier.; Martin, Peter.; Heers, Ashley M.; Serrano, Francisco J.; Habib, Michael B.; Dececchi, T. Alexander.; Kaye, Thomas G.; Larsson, Hans C.E.; Wang, Xiaoli.; Zheng, Xiaoting.; Novas, Fernando E.; Agnolín, Federico L.; Egli, Federico Brisson.; Lo Coco, Gastón E.Introduction / Michael Pittman and Xing Xu -- Section 1. Systematics, fossil record, and biogeography -- Chapter 1. Pennaraptoran systematics / Michael Pittman, Jingmai O’Connor, Daniel J. Field, Alan H. Turner, Waisum Ma, Peter Makovicky, and Xing Xu -- Chapter 2. The fossil record of Mesozoic and Paleocene pennaraptorans / Michael Pittman, Jingmai O’Connor, Edison Tse, Peter Makovicky, Daniel J. Field, Waisum Ma, Alan H. Turner, Mark A. Norell, Rui Pei, and Xing Xu -- Chapter 3. The impact of unstable taxa in coelurosaurian phylogeny and resampling support measures for parsimony analyses / Diego Pol and Pablo A. Goloboff -- Chapter 4. The biogeography of coelurosaurian theropods and its impact on their evolutionary history / Anyang Ding, Michael Pittman, Paul Upchurch, Jingmai O’Connor, Daniel J. Field, and Xing Xu -- Chapter 5. Timing the extant avian radiation : the rise of modern birds, and the importance of modeling molecular rate variation / Daniel J. Field, Jacob S. Berv, Allison Y. Hsiang, Robert Lanfear, Michael J. Landis, and Alex Dornburg -- Section 2. Anatomical frontiers -- Chapter 6. Disparity and macroevolutionary transformation of the maniraptoran manus / Sergio M. Nebreda, Guillermo Navalón, Iris Menéndez, Trond Sigurdsen, Luis M. Chiappe, and Jesús Marugán-Lobón -- Chapter 7. Tooth vs. beak : the evolutionary developmental control of the avian feeding apparatus / Shuo Wang, Josef Stiegler, Ping Wu, and Cheng-ming Chuong -- Chapter 8. Functional morphology of the oviraptorosaurian and scansoriopterygid skull / Waisum Ma, Michael Pittman, Stephan Lautenschlager, Luke E. Meade, and Xing Xu -- Chapter 9. Fossil microbodies are melanosomes : evaluating and rejecting the ‘fossilised decay-associated microbes’ hypothesis / Arindam Roy, Christopher S. Rogers, Thomas Clements, Michael Pittman, Olivier Habimana, Peter Martin, and Jakob Vinther -- Section 3. Early-flight study : methods, status, and frontiers -- Chapter 10. Methods of studying early theropod flight / Michael Pittman, Ashley M. Heers, Francisco J. Serrano, Daniel J. Field, Michael B. Habib, T. Alexander Dececchi, Thomas G. Kaye, and Hans C.E. Larsson -- Chapter 11. High flyer or high fashion? A comparison of flight potential among small-bodied paravians / T. Alexander Dececchi, Hans C.E. Larsson, Michael Pittman, and Michael B. Habib -- Chapter 12. Navigating functional landscapes : a bird’s eye view of the evolution of avialan flight / Hans C.E. Larsson, Michael B. Habib, and T. Alexander Dececchi -- Chapter 13. Laser-stimulated fluorescence refines flight modeling of the Early Cretaceous bird Sapeornis / Francisco J. Serrano, Michael Pittman, Thomas G. Kaye, Xiaoli Wang, Xiaoting Zheng, and Luis M. Chiappe -- Chapter 14. Pectoral girdle morphology in early-diverging paravians and living ratites : implications for the origin of flight / Fernando E. Novas, Federico L. Agnolín, Federico Brisson Egli, and Gastón E. Lo Coco.Item Skeletal morphology of Mononykus olecranus (Theropoda, Avialae) from the late Cretaceous of Mongolia. American Museum novitates ; no.3105(New York, N.Y. : American Museum of Natural History, 1994) Altangerel, Perle.; Chiappe, Luis M.; Rinchen, Barsbold.; Clark, James Matthew, 1956-; Norell, Mark.; Mongolyn Shinzhlėkh Ukhaany Akademi.Item Stratigraphy and magnetostratigraphic/faunal constraints for the age of sauropod embryo-bearing rocks in the Neuquén Group (Late Cretaceous, Neuquén Province, Argentina). American Museum novitates ; no. 3290(New York, NY : American Museum of Natural History, 2000) Dingus, Lowell.; Clarke, Julia A.; Scott, Gary Robert, 1946-; Swisher, Carl Celso.; Chiappe, Luis M.; Coria, Rodolfo A.The stratigraphy and age of a sauropod nesting ground containing the first definitive embryonic remains of sauropods preserved inside their eggs is analyzed. The fossil locality, called Auca Mahuevo, occurs in the Anacleto Member of the Río Colorado Formation in Neuquén Province, Argentina. The 5 m thick interval of overbank mudstones containing the fossilized eggs and embryos occurs near the middle of a 35 m sequence of thin, fluvial, concretionary sandstones and thicker units of silty sandstone. Flooding of shallow stream channels deposited overbank silt and mud on the eggs, killing the embryos and initiating the process of fossilization. Egg fragments containing patches of fossilized integument were found as float weathering out of the mudstone on local flats. Complete eggs containing embryonic bones and teeth were quarried from a steep ridge where the mudstone was exposed. Twelve paleomagnetic samples collected throughout the lower 30 m of the section establish the presence of a Reverse geomagnetic polarity interval. This constitutes the first magnetostratigraphic characterization for this part of the Río Colorado Formation and for the late Cretaceous sequence of formations that comprise the Neuquén Group. Biochronologic age estimates for the Río Colorado fauna combined with the Reverse polarity determinations for the fossiliferous sediments in the Anacleto Member argue for an age younger than the long Cretaceous C34 Normal, which ends at the upper boundary of the Sartonian and older than the late Campanian. The Reverse interval containing the fossils at Auca Mahuevo is therefore considered to be early or middle Campanian in age, most likely correlative with C33R between 83.5 and 79.5 Ma.Item Supplemental Material for 'Pennaraptoran theropod dinosaurs : past progress and new frontiers. (Bulletin of the American Museum of Natural History, no. 440)'(American Museum of Natural History., 2020-08-21) Pittman, Michael, 1985-; Xu, Xing, 1969-; O'Connor, Jingmai.; Field, Daniel J.; Turner, Alan H. (Alan Hamilton); Ma, Waisum.; Makovicky, Peter J.; Tse, Edison.; Norell, Mark.; Pei, Rui.; Pol, Diego.; Goloboff, Pablo A.; Ding, Anyang.; Upchurch, Paul.; Berv, Jacob S.; Hsiang, Allison Y.; Landis, Michael J.; Dornburg, Alex.; Nebreda, Sergio M.; Navalón, Guillermo.; Menéndez, Iris.; Sigurdsen, Trond; Chiappe, Luis M.; Marugán-Lobón, Jesús.; Wang, Shuo.; Stiegler, Josef.; Wu, Ping.; Zhong, Zhengming.; Lautenschlager, Stephan.; Meade, Luke E.; Roy, Arindam.; Rogers, Christopher S.; Clements, Thomas.; Habimana, Olivier.; Martin, Peter.; Heers, Ashley M.; Serrano, Francisco J.; Habib, Michael B.; Dececchi, T. Alexander.; Kaye, Thomas G.; Larsson, Hans C.E.; Wang, Xiaoli.; Zheng, Xiaoting.; Novas, Fernando E.; Agnolín, Federico L.; Egli, Federico Brisson.; Lo Coco, Gastón E.Supplemental Material for 'Pennaraptoran theropod dinosaurs : past progress and new frontiers. (Bulletin of the American Museum of Natural History, no. 440)'