Papers by Peter Makovicky
Background
Eolambia caroljonesa is the most abundant dinosaur in the lower Cenomanian Mussentuchi... more Background
Eolambia caroljonesa is the most abundant dinosaur in the lower Cenomanian Mussentuchit
Member of the Cedar Mountain Formation of Utah, and one of the most completely known
non-hadrosaurid iguanodontians from North America. In addition to the large holotype and
paratype partial skulls, copious remains of skeletally immature individuals, including three
bonebeds, have been referred to E. caroljonesa. Nevertheless, aspects of the postcranial
anatomy of this taxon, particularly the pelvic girdle, have remained ambiguous due to the
lack of associated postcranial material of larger, more mature individuals.
Methodology/Principal findings
Here we describe a recently discovered associated partial postcranial skeleton of a large
Eolambia caroljonesa. This specimen, FMNH PR 3847, provides new anatomical data
regarding the vertebral column and pelvic girdle, supplementing previous diagnoses and
descriptions of E. caroljonesa. A new phylogenetic analysis incorporating information from
FMNH PR 3847 places E. caroljonesa as a basal hadrosauromorph closely related to Protohadros
byrdi from the Cenomanian Woodbine Formation of Texas. Histological analysis of
FMNH PR 3847 reveals that it represents a subadult individual eight to nine years of age.
Taphonomic analysis indicates that FMNH PR 3847 was preserved in a crevasse splay
deposit, along with an unusual abundance of small crocodylomorph material.
American Museum Novitates
Journal of Evolutionary Biology
The Hanson Formation of the Central Transantarctic Mountains has yielded a diverse Early Jurassic... more The Hanson Formation of the Central Transantarctic Mountains has yielded a diverse Early Jurassic terrestrial fauna, which includes the nearly complete theropod dinosaur, Cryolophosaurus ellioti, and a fragmentary basal sauropodomorph dinosaur. The Hanson Formation dinosaurs are important for understanding early dinosaur evolution because: 1) they preserve a mosaic of morphological traits that render them useful for interpreting poorly known parts of the dinosaur evolutionary tree; 2) they are from the Early Jurassic, a critical period in early dinosaur evolution about which knowledge is scant; and 3) they are the only known Early Jurassic dinosaurs from Antarctica, making them particularly valuable for understanding patterns of biotic interchange during this time. Recent research suggests that Cryolophosaurus belongs to a geographically widespread clade of mid-sized, Early Jurassic theropods with cranial crests that includes Dilophosaurus wetherilli, 'Dilophosaurus' sinensi...
Zoological Journal of the Linnean Society
, from the Early Jurassic Hanson Formation of the Central Transantarctic Mountains, represents a ... more , from the Early Jurassic Hanson Formation of the Central Transantarctic Mountains, represents a theropod dinosaur from a period of time and geographical area that are poorly sampled with respect to dinosaur taxa. An in-depth morphological description of Cryolophosaurus is presented here, along with a rigorous phylogenetic analysis of theropod relationships consisting of 347 characters and 56 taxa, in an attempt to clarify the relationships of Cryolophosaurus and to provide insight into questions surrounding early theropod evolution. Cryolophosaurus is characterized by a unique cranial crest, formed primarily by the lacrimals, a pronounced constriction of the squamosal and jugal bones across the infratemporal fenestra, and extremely elongate cranial processes on the cervical ribs. Several shared characters, including the presence of a slotshaped foramen at the base of the nasal process of the premaxilla, nasolacrimal crests and erect tab-like dorsal processes on the articular, suggest affinities between Cryolophosaurus and a clade of medium-bodied Early Jurassic theropods that includes ' Dilophosaurus ' sinensis , Dracovenator regenti and Dilophosaurus wetherilli . This clade is recovered as sister-taxon to a Neoceratosauria + Tetanurae clade, rendering both a traditional Coelophysoidea and Ceratosauria non-monophyletic. Cryolophosaurus represents the largest known Early Jurassic theropod, and marks the beginning of theropod occupation of the dominant predator niche in the Mesozoic.
The Cedar Mountain Formation is comprised of five members spanning approximately 30 million years... more The Cedar Mountain Formation is comprised of five members spanning approximately 30 million years of dinosaur evolution in western North America. The sequence is of particular interest for bracketing the transition from Early to Late Cretaceous vertebrate faunas in the region and for refining the appearance of taxa with putative Asian affinities. Recent work continues to reveal new information about the diversity, paleobiogeography, and extinction patterns of theropods in the otherwise poorly understood mid-Cretaceous gap. To date, the best species-specific theropod record derives from the Aptian-aged Yellow Cat Member, which preserves the large-bodied dromaeosaurid Utahraptor, the primitive therizinosaurian Falcarius, and the indeterminate coelurosaurian Nedcolbertia. However, the greatest diversity record stems from the youngest and westernmost unit, the Cenomanian-aged Mussentuchit Member. Intensive sampling of teeth from microvertebrate localities in the Mussentuchit indicates t...
The Anatomical Record, 2015
Appendix S1. List of characters and characterstates used in phylogenetic analysis. Original citat... more Appendix S1. List of characters and characterstates used in phylogenetic analysis. Original citations and/or modifications are provided in parantheses. The abbreviation "TWiG" is used to denote characters derived or modified from the Theropod Working Group Matrix.
Appendix S2. Taxoncharacter state data matrix used in the phylogenetic analysis. "0, 1, 2, 3, 4" ... more Appendix S2. Taxoncharacter state data matrix used in the phylogenetic analysis. "0, 1, 2, 3, 4" = character states; "?" = unknown; multistate codings separated by backslashes = uncertainty; "" = inapplicable.
Fieldiana Life and Earth Sciences, 2012
A new coelurosaurian theropod, Alnashetri cerropoliciensis, is reported here based on articulated... more A new coelurosaurian theropod, Alnashetri cerropoliciensis, is reported here based on articulated hind limbs of a single individual discovered at the locality of La Buitrera (Candeleros Formation, Cenomanian-Turonian), Río Negro Province, Argentina. The new taxon differs from other coelurosaurs in the possession of a low ridge that separates the rostral tibial surface from the outer face of the lateral malleolus, and which extends proximally beyond the tip of the ascending process of the astragalus, and in the possession of ventral notches on the hemicondyles of the distal articulations on pedal phalanges III-1 and III-2. Alnashetri is easily distinguished from the dromaeosaurid Buitreraptor, the only other known small theropod from La Buitrera. Phylogenetic analysis supports alvarezsauroid affinities. The evidence supporting this relationship comes from the detailed anatomy of the ankle, however, and this concentration of character support within a single anatomical region may bias our results. If our proposed phylogenetic placement is accurate, Alnashetri antedates all other Argentinian alvarezsaurids and indicates that alvarezsaurids were present in the Neuquén Basin throughout the entire Late Cretaceous.
The Evolutionary History of Modern Birds, 2011
Proceedings. Biological sciences / The Royal Society, Jan 22, 2014
Ecological divergence is thought to be coupled with evolutionary radiations, yet the strength of ... more Ecological divergence is thought to be coupled with evolutionary radiations, yet the strength of this coupling is unclear. When birds diversified ecologically has received much less attention than their hotly debated crown divergence time. Here, we quantify how accurately skeletal morphology can predict ecology in living and extinct birds, and show that the earliest known assemblage of birds (=pygostylians) from the Jehol Biota (≈125 Ma) was substantially impoverished ecologically. The Jehol avifauna has few representatives of highly preservable ecomorphs (e.g. aquatic forms) and a notable lack of ecomorphological overlap with the pterosaur assemblage (e.g. no large or aerially foraging pygostylians). Comparisons of the Jehol functional diversity with modern and subfossil avian assemblages show that taphonomic bias alone cannot explain the ecomorphological impoverishment. However, evolutionary simulations suggest that the constrained ecological diversity of the Early Cretaceous pygo...
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Papers by Peter Makovicky
Eolambia caroljonesa is the most abundant dinosaur in the lower Cenomanian Mussentuchit
Member of the Cedar Mountain Formation of Utah, and one of the most completely known
non-hadrosaurid iguanodontians from North America. In addition to the large holotype and
paratype partial skulls, copious remains of skeletally immature individuals, including three
bonebeds, have been referred to E. caroljonesa. Nevertheless, aspects of the postcranial
anatomy of this taxon, particularly the pelvic girdle, have remained ambiguous due to the
lack of associated postcranial material of larger, more mature individuals.
Methodology/Principal findings
Here we describe a recently discovered associated partial postcranial skeleton of a large
Eolambia caroljonesa. This specimen, FMNH PR 3847, provides new anatomical data
regarding the vertebral column and pelvic girdle, supplementing previous diagnoses and
descriptions of E. caroljonesa. A new phylogenetic analysis incorporating information from
FMNH PR 3847 places E. caroljonesa as a basal hadrosauromorph closely related to Protohadros
byrdi from the Cenomanian Woodbine Formation of Texas. Histological analysis of
FMNH PR 3847 reveals that it represents a subadult individual eight to nine years of age.
Taphonomic analysis indicates that FMNH PR 3847 was preserved in a crevasse splay
deposit, along with an unusual abundance of small crocodylomorph material.
Eolambia caroljonesa is the most abundant dinosaur in the lower Cenomanian Mussentuchit
Member of the Cedar Mountain Formation of Utah, and one of the most completely known
non-hadrosaurid iguanodontians from North America. In addition to the large holotype and
paratype partial skulls, copious remains of skeletally immature individuals, including three
bonebeds, have been referred to E. caroljonesa. Nevertheless, aspects of the postcranial
anatomy of this taxon, particularly the pelvic girdle, have remained ambiguous due to the
lack of associated postcranial material of larger, more mature individuals.
Methodology/Principal findings
Here we describe a recently discovered associated partial postcranial skeleton of a large
Eolambia caroljonesa. This specimen, FMNH PR 3847, provides new anatomical data
regarding the vertebral column and pelvic girdle, supplementing previous diagnoses and
descriptions of E. caroljonesa. A new phylogenetic analysis incorporating information from
FMNH PR 3847 places E. caroljonesa as a basal hadrosauromorph closely related to Protohadros
byrdi from the Cenomanian Woodbine Formation of Texas. Histological analysis of
FMNH PR 3847 reveals that it represents a subadult individual eight to nine years of age.
Taphonomic analysis indicates that FMNH PR 3847 was preserved in a crevasse splay
deposit, along with an unusual abundance of small crocodylomorph material.