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.
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...
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...
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...
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.
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...
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...
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.