Taxonomic status of Nanotyrannus lancensis (Dinosauria: Tyrannosauroidea) — a distinct taxon of small-bodied tyrannosaur DOI Open Access
Nicholas R. Longrich, Evan T. Saitta

Published: Oct. 23, 2023

Abstract: Tyrannosaurs, giant predatory dinosaurs from the end of Cretaceous, are among most intensively researched and best-known groups dinosaurs. Despite this, their relationships systematics highly controversial, number tyrannosaur species occurring in latest Cretaceous North America is debated. An ongoing debate concerns status Nanotyrannus lancensis, which has variously been interpreted as a distinct taxon small-bodied or juvenile coeval Tyrannosaurus rex. Here, we review multiple lines evidence show that totality strongly supports recognition species: 1. The high diversity Late tyrannosaurs general consistent with idea more than one lived late Maastrichtian Western America; 2. shows few if any diagnostic characters allowing referral specifically to even Tyrannosaurinae, but differentiated T. rex by at least 77 morphological characters, while intermediate forms, combining characteristics rex, remain unknown; 3. Histological individuals previously referred lancensis (i) skeletal fusions maturity, (ii) skull bone textures (iii) slow growth rates relative (iv) decelerating final years life, (v) curves predicting adult body sizes ~1500 kg less, implying these animals young adults, not juveniles Tyrannosaurus; 4. Juveniles other tyrannosaurids, including Gorgosaurus Tarbosaurus, do kinds changes proposed for Nanotyrannus-Tyrannosaurus series, suggesting morphology cannot simply be explained result immaturity; 5. Small exist, comparable size Nanotyrannus, exhibit features Tyrannosaurus, differ Nanotyrannus; 6. Phylogenetic analysis suggests tyrannosaurid. Taken together, rejects tentatively placement outside Tyrannosauridae non-tyrannosaurid member Tyrannosauroidea. Tyrannosaur appears have higher appreciated before K-Pg extinction. difficulties recognizing based on fossils alone mean paleontologists may systematically biased towards underestimating ancient ecosystems.

Language: Английский

A new abelisaurid dinosaur from the end Cretaceous of Patagonia and evolutionary rates among the Ceratosauria DOI Creative Commons
Diego Pol, Mattia A. Baiano, David Černý

et al.

Cladistics, Journal Year: 2024, Volume and Issue: 40(3), P. 307 - 356

Published: May 21, 2024

Abstract Gondwanan dinosaur faunae during the 20 Myr preceding Cretaceous–Palaeogene (K/Pg) extinction included several lineages that were absent or poorly represented in Laurasian landmasses. Among these, South American fossil record contains diverse abelisaurids, arguably most successful groups of carnivorous dinosaurs from Gondwana Cretaceous, reaching their highest diversity towards end this period. Here we describe Koleken inakayali gen. et sp. n., a new abelisaurid La Colonia Formation (Maastrichtian, Upper Cretaceous) Patagonia. is known skull bones, an almost complete dorsal series, sacrum, caudal vertebrae, pelvic girdle and hind limbs. The shows unique set features anatomical differences Carnotaurus sastrei (the only other Formation). retrieved as brachyrostran abelisaurid, clustered with abelisaurids latest Cretaceous (Campanian–Maastrichtian), such Aucasaurus , Niebla . Leveraging our phylogeny estimates, explore rates morphological evolution across ceratosaurian lineages, finding them to be particularly high for elaphrosaurine noasaurids around base Abelisauridae, before Early radiation latter clade. Noasauridae sister clade show contrasting patterns evolution, undergoing early phase accelerated axial limb skeleton Jurassic, exhibiting sustained cranial Cretaceous. These results provide much needed context evolutionary dynamics theropods, contributing broader understanding macroevolutionary dinosaurs.

Language: Английский

Citations

11
Taxonomic Status of Nanotyrannus lancensis (Dinosauria: Tyrannosauroidea)—A Distinct Taxon of Small-Bodied Tyrannosaur DOI Open Access
Nicholas R. Longrich, Evan T. Saitta

Fossil Studies, Journal Year: 2024, Volume and Issue: 2(1), P. 1 - 65

Published: Jan. 3, 2024

Tyrannosaurs are among the most intensively studied and best-known dinosaurs. Despite this, their relationships systematics highly controversial. An ongoing debate concerns validity of Nanotyrannus lancensis, interpreted either as a distinct genus small-bodied tyrannosaur or juvenile Tyrannosaurus rex. We examine multiple lines evidence show that strongly supports recognition species for following reasons: 1. High diversity tyrannosaurs predatory dinosaurs idea tyrannosaurids inhabited late Maastrichtian Laramidia; 2. lacks characters supporting referral to Tyrannosaurinae but differs from T. rex in >150 morphological characters, while intermediate forms combining features unknown; 3. Histology shows specimens showing (i) skeletal fusions, (ii) mature skull bone textures, (iii) slow growth rates relative rex, (iv) decelerating final years life, (v) curves predicting adult masses ~1500 kg less, these animals subadults young adults, not Tyrannosaurus; 4. series other tyrannosaurids, including Tarbosaurus Gorgosaurus, do changes proposed Nanotyrannus–Tyrannosaurus series, deriving requires several inconsistent with known patterns dinosaur development; 5. Juvenile exist, diagnostic 6. Phylogenetic analysis suggests may lie outside Tyrannosauridae. Tyrannosaur before K-Pg extinction is higher than previously appreciated. The challenges inherent diagnosing based on fossils mean paleontologists be systematically underestimating ancient ecosystems.

Language: Английский

Citations

10
A new small duckbilled dinosaur (Hadrosauridae: Lambeosaurinae) from Morocco and dinosaur diversity in the late Maastrichtian of North Africa DOI Creative Commons
Nicholas R. Longrich, Xabier Pereda Suberbiola, Nathalie Bardet

et al.

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: Feb. 13, 2024

Abstract In the Late Cretaceous, northern and southern hemispheres evolved distinct dinosaurian faunas. Titanosaurians abelisaurids dominated Gondwanan continents; hadrosaurids, ceratopsians tyrannosaurs North America Asia. Recently, a lambeosaurine hadrosaurid, Ajnabia odysseus , was reported from late Maastrichtian phosphates of Oulad Abdoun Basin Morocco, suggesting dispersal between Laurasia Gondwana. Here we report new fossils Morocco showing lambeosaurines achieved high diversity in Africa. A skull represents dwarf lambeosaurine, Minqaria bata . resembles size, but differs ventrally positioned jugal facet sinusoidal toothrow. The animal is small, ~ 3.5 m long, fused braincase shows it mature. humerus femur belong to larger 6 implying at least three species coexisted. hadrosaurids Europe Africa suggests dispersal-driven radiation, with diversifying take advantage low ornithischian diversity. African are small compared American Asia however, perhaps due competition titanosaurians. Hadrosaurids unknown eastern Africa, Moroccan may be part insular fauna, represent an island radiation.

Language: Английский

Citations

9
A brief review of non-avian dinosaur biogeography: state-of-the-art and prospectus DOI Creative Commons
Paul Upchurch, Alfio Alessandro Chiarenza

Biology Letters, Journal Year: 2024, Volume and Issue: 20(10)

Published: Oct. 1, 2024

Dinosaurs potentially originated in the mid-palaeolatitudes of Gondwana 245–235 million years ago (Ma) and may have been restricted to cooler, humid areas by low-latitude arid zones until climatic amelioration made northern dispersals feasible ca 215 Ma. However, this scenario is challenged new Carnian Laurasian fossils evidence that even earliest dinosaurs had adaptations for conditions. After becoming globally distributed Early–Middle Jurassic (200–160 Ma), experienced vicariance driven Pangaean fragmentation. Regional extinctions trans-oceanic also played a role, formation ephemeral land connections meant older patterns were repeatedly overprinted younger ones, creating reticulate biogeographic history. Palaeoclimates shaped dispersal barriers corridors, including filters differential effects on different types dinosaurs. Dinosaurian research faces many challenges, not least which patchiness fossil record. fossils, extensive databasing improved analytical methods help distinguish signal from noise generate fresh perspectives. In future, developing techniques quantifying ameliorating sampling biases modelling capacities are likely be two key components our modern programme.

Language: Английский

Citations

4
Historical bias in palaeontological collections: Stylophora (Echinodermata) as a case study DOI Creative Commons
Pauline Guenser,

Khadija El Hariri,

Nour‐Eddine Jalil

et al.

Swiss Journal of Palaeontology, Journal Year: 2025, Volume and Issue: 144(1)

Published: Jan. 21, 2025

Abstract Scientific colonialism (sensu Galtung, 1967) has grown in interest for the last decades all scientific disciplines, including Palaeontology. In particular, Raja et al. (2022) showed that Paleobiology Database (PBDB) was mostly based on research investigations from and/or higher-income countries (i.e., Global North). This practice, better known as “parachute science”, often implies a transfer of material their country origin (in South) to another collection We show this global pattern can also be observed at lower taxonomic scale by focusing Stylophora, an extinct class echinoderms. Based database gathering 129 stylophoran holotypes information year description, origin, and author affiliation, we comparable results those (2022). Indeed, 85% species originated North. Transferred represents 17% none corresponding publications included local collaboration. detail most highlighting example parachute science, duo Morocco-France, understand consequences colonial history between these two practice French researchers Morocco, well solution brought Moroccan government. These results, while not surprising, mean is indeed only databases, but our daily work. Researchers North then act decolonize problematic rebalance knowledge producing build true Research Community.

Language: Английский

Citations

0
Evolutionary and paleobiogeographic implications of new carcharodontosaurian, megaraptorid, and unenlagiine theropod remains from the upper Lower Cretaceous of Victoria, southeast Australia DOI Creative Commons
Jake Kotevski, Ruairidh J. Duncan, Tim Ziegler

et al.

Journal of Vertebrate Paleontology, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 19, 2025

Language: Английский

Citations

0
Farlowichnus rapidus new ichnogen., new ichnosp.: A speedy and small theropod in the Early Cretaceous Botucatu paleodesert (Paraná Basin), Brazil DOI
Giuseppe Leonardi, Marcelo Adorna Fernandes, Ismar de Souza Carvalho

et al.

Cretaceous Research, Journal Year: 2023, Volume and Issue: 153, P. 105720 - 105720

Published: Sept. 29, 2023

Language: Английский

Citations

5
Caletodraco cottardi: A New Furileusaurian Abelisaurid (Dinosauria: Theropoda) from the Cenomanian Chalk of Normandy (North-Western France) DOI Open Access
Éric Buffetaut, Haiyan Tong,

Jérôme Girard

et al.

Fossil Studies, Journal Year: 2024, Volume and Issue: 2(3), P. 177 - 195

Published: Aug. 19, 2024

An articulated group of skeletal elements comprising a sacrum, both ilia and first caudal vertebra, plus an isolated tooth found in immediate proximity to the bones, from lower Cenomanian Chalk at Saint-Jouin-Bruneval (Seine-Maritime, Normandy, France) is described attributed new genus species abelisaurid theropod, Caletodraco cottardi, on basis several characters sacrum pelvis. The peculiar shape transverse process vertebra shows that cottardi differs majungasaurine abelisaurids previously Europe, such as Arcovenator escotae, belongs Furileusauria, derived hitherto recognized only South America. presence furileusaurian Normandy suggests biogeographical history Abelisauridae Europe was more complex than admitted. Several European abelisaurids, Albian Genusaurus sisteronis, may fact belong Furileusauria.

Language: Английский

Citations

1
A New Species of the Durophagous Mosasaurid Carinodens from the Late Maastrichtian Phosphates of Morocco and Implications for Maastrichtian Mosasaurid Diversity DOI Creative Commons
Nicholas R. Longrich, Xabier Pereda Suberbiola, Nour‐Eddine Jalil

et al.

Diversity, Journal Year: 2024, Volume and Issue: 17(1), P. 25 - 25

Published: Dec. 29, 2024

Late Cretaceous marine ecosystems saw a major adaptive radiation of mosasaurids, which evolved highly disparate jaw and tooth morphologies to feed on different prey. A striking pattern seen in mosasaurids was high diversity durophagous forms. Durophagy likely several times independently the mosasaurine genera Globidens, Prognathodon, Carinodens. Carinodens is unusual having low, rectangular, laterally compressed teeth. The genus known from around world, with species minalmamar C. belgicus previously reported Maastrichtian Phosphates Morocco. Here, we report new Carinodens, acrodon, same Phosphates. It characterized by teeth tall crowns, triangular apices, broad bases. Many diagnostic features this appear be plesiomorphies, suggesting persistence primitive into latest alongside more derived belgicus. contributes an emerging mosasaurid hyperdiversity late revised faunal list, including stratigraphic range extensions Khinjaria Stelladens upper Couche III Morocco, suggests at least 16 mosasauroid coexisted here.

Language: Английский

Citations

1
Taxonomic status of Nanotyrannus lancensis (Dinosauria: Tyrannosauroidea) — a distinct taxon of small-bodied tyrannosaur DOI Open Access
Nicholas R. Longrich, Evan T. Saitta

Published: Oct. 23, 2023

Abstract: Tyrannosaurs, giant predatory dinosaurs from the end of Cretaceous, are among most intensively researched and best-known groups dinosaurs. Despite this, their relationships systematics highly controversial, number tyrannosaur species occurring in latest Cretaceous North America is debated. An ongoing debate concerns status Nanotyrannus lancensis, which has variously been interpreted as a distinct taxon small-bodied or juvenile coeval Tyrannosaurus rex. Here, we review multiple lines evidence show that totality strongly supports recognition species: 1. The high diversity Late tyrannosaurs general consistent with idea more than one lived late Maastrichtian Western America; 2. shows few if any diagnostic characters allowing referral specifically to even Tyrannosaurinae, but differentiated T. rex by at least 77 morphological characters, while intermediate forms, combining characteristics rex, remain unknown; 3. Histological individuals previously referred lancensis (i) skeletal fusions maturity, (ii) skull bone textures (iii) slow growth rates relative (iv) decelerating final years life, (v) curves predicting adult body sizes ~1500 kg less, implying these animals young adults, not juveniles Tyrannosaurus; 4. Juveniles other tyrannosaurids, including Gorgosaurus Tarbosaurus, do kinds changes proposed for Nanotyrannus-Tyrannosaurus series, suggesting morphology cannot simply be explained result immaturity; 5. Small exist, comparable size Nanotyrannus, exhibit features Tyrannosaurus, differ Nanotyrannus; 6. Phylogenetic analysis suggests tyrannosaurid. Taken together, rejects tentatively placement outside Tyrannosauridae non-tyrannosaurid member Tyrannosauroidea. Tyrannosaur appears have higher appreciated before K-Pg extinction. difficulties recognizing based on fossils alone mean paleontologists may systematically biased towards underestimating ancient ecosystems.

Language: Английский

Citations

0