A new maniraptoran femur with alvarezsaurian affinities from the Plottier Formation (Coniacian-Santonian), northern Patagonia DOI
Federico A. Gianechini, Jorge Gustavo Meso, Ariel H. Méndez

et al.

Historical Biology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 11

Published: Oct. 16, 2024

A new specimen, MAU-Pv-PH-453, comprising an isolated femur from the Plottier Formation (Coniacian-Santonian), northern Patagonia, is described here. Its characteristics, i.e., anteriorly curved diaphysis; fused lesser and greater trochanters forming a trochanteric crest; prominent medially directed head; absence of fourth trochanter, allow us to identify it as belonging maniraptoran theropod. Among Patagonian maniraptorans, MAU-Pv-PH-453 shares similarities with alvarezsaurians, such posterior shelf, trochanter. However, in alvarezsaurs, are generally separated by cleft. Notably, exhibits some features seen femora parvicursorine alvarezsaurids, including proximally projected crest L-shaped profile proximal view. presents differences parvicursorines, knob partially separating trochanters. Phylogenetically, may have affinities, although its fragmentary nature might generate bias phylogenetic position. Due lack more diagnostic characters, assigned Alvarezsauria indet. This material represents second theropod record could fill temporal gap (between Coniacian Santonian) Upper Cretaceous alvarezsaurians.

Language: Английский

Rise of the king: Gondwanan origins and evolution of megaraptoran dinosaurs DOI Creative Commons
Cassius Morrison, Charlie Roger Scherer,

Ezekiel V. O’Callaghan

et al.

Royal Society Open Science, Journal Year: 2025, Volume and Issue: 12(5)

Published: May 1, 2025

Late Cretaceous Earth was dominated by theropods such as tyrannosauroids and megaraptorans; however, it is unclear how these clades diversified grew to massive proportions. This study aimed conduct a biogeographical analysis test climate potential mechanism for the increase in size. We used published phylogenetic matrices with R package BioGeoBears different hypotheses both clades. mapped body mass (BM) length against known data this hypothesis. Continental-scale variance did not drive tyrannosauroid biogeography instead widespread ancestral populations, sympatric speciation localized extinctions throughout constricted geographic range. Both patterns were supported statistical analyses. model also indicates ancestor of clade Tarbosaurus Tyrannosaurus present Asia Laramidia, therefore came from Asia. Statistical illustrated no correlation between Mean Annual Temperature (MAT) BM but climatic shifts may be associated gigantism derived megaraptorids eutyrannosaurians. implies megaraptorans have had cosmopolitan distribution prior splitting Laurasia Gondwana. Also, Cretaceous.

Language: Английский

Citations

0
Theropod dinosaur diversity of the lower English Wealden: analysis of a tooth‐based fauna from the Wadhurst Clay Formation (Lower Cretaceous: Valanginian) via phylogenetic, discriminant and machine learning methods DOI Creative Commons
Chris T. Barker,

Lucy Handford,

Darren Naish

et al.

Papers in Palaeontology, Journal Year: 2024, Volume and Issue: 10(6)

Published: Nov. 1, 2024

Abstract The Lower Cretaceous Wealden Supergroup of southern England yields a diverse assemblage theropod dinosaurs, its taxa being represented by fragments in addition to some the most informative associated skeletons European Mesozoic. Spinosaurids, neovenatorid allosauroids, tyrannosauroids and dromaeosaurids are among reported clades. However, majority relevant specimens from Barremian Upper Weald Clay Wessex formations, diversity older Berriasian–Valanginian Hastings Group has remained poorly known, fragmentary thus far remaining enigmatic both terms phylogenetic affinities sometimes provenance. A better understanding would be welcome given paucity dinosaurs worldwide. Here, we describe an teeth Valanginian Wadhurst Formation, mostly collected Ashdown Brickworks locality near Bexhill, East Sussex. These were assessed using phylogenetic, discriminant machine learning analyses found include members Spinosauridae, Tyrannosauroidea Dromaeosauridae, others that remain uncertain affinity within Coelurosauria. appear distinct those already known strata: spinosaurid cannot referred Baryonyx or tyrannosauroid Eotyrannus , for example, but have not named new at this time. Combined with other findings our study indicates was comparable younger units, implying ‘characteristic’ components faunas established early deposition famous geological succession.

Language: Английский

Citations

2
A new maniraptoran femur with alvarezsaurian affinities from the Plottier Formation (Coniacian-Santonian), northern Patagonia DOI
Federico A. Gianechini, Jorge Gustavo Meso, Ariel H. Méndez

et al.

Historical Biology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 11

Published: Oct. 16, 2024

A new specimen, MAU-Pv-PH-453, comprising an isolated femur from the Plottier Formation (Coniacian-Santonian), northern Patagonia, is described here. Its characteristics, i.e., anteriorly curved diaphysis; fused lesser and greater trochanters forming a trochanteric crest; prominent medially directed head; absence of fourth trochanter, allow us to identify it as belonging maniraptoran theropod. Among Patagonian maniraptorans, MAU-Pv-PH-453 shares similarities with alvarezsaurians, such posterior shelf, trochanter. However, in alvarezsaurs, are generally separated by cleft. Notably, exhibits some features seen femora parvicursorine alvarezsaurids, including proximally projected crest L-shaped profile proximal view. presents differences parvicursorines, knob partially separating trochanters. Phylogenetically, may have affinities, although its fragmentary nature might generate bias phylogenetic position. Due lack more diagnostic characters, assigned Alvarezsauria indet. This material represents second theropod record could fill temporal gap (between Coniacian Santonian) Upper Cretaceous alvarezsaurians.

Language: Английский

Citations

0