Science, Journal Year: 2022, Volume and Issue: 375(6578)
Published: Jan. 20, 2022
Schroeder et al. (Reports, 26 February 2021, p. 941) reported a size gap among predatory dinosaur species. We argue that the supporting dataset is skewed toward Late Cretaceous North America and was likely absent during other intervals in most geographic regions. urge broader consideration of this hypothesis, with quantitative evaluation preservational biases.
Language: Английский
Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)
Published: June 29, 2021
The question why non-avian dinosaurs went extinct 66 million years ago (Ma) remains unresolved because of the coarseness fossil record. A sudden extinction caused by an asteroid is most accepted hypothesis but it debated whether were in decline or not before impact. We analyse speciation-extinction dynamics for six key dinosaur families, and find a across dinosaurs, where diversification shifted to declining-diversity pattern ~76 Ma. investigate influence ecological physical factors, that was likely driven global climate cooling herbivorous diversity drop. latter due hadrosaurs outcompeting other herbivores. also estimate risk related species age during decline, suggesting lack evolutionary novelty adaptation changing environments. These results support environmentally well
Language: Английский
Citations
67
Earth-Science Reviews, Journal Year: 2023, Volume and Issue: 244, P. 104537 - 104537
Published: Aug. 8, 2023
Language: Английский
Citations
22
PLoS ONE, Journal Year: 2024, Volume and Issue: 19(3), P. e0298957 - e0298957
Published: March 6, 2024
The lifestyle of spinosaurid dinosaurs has been a topic lively debate ever since the unveiling important new skeletal parts for Spinosaurus aegyptiacus in 2014 and 2020. Disparate lifestyles this taxon have proposed literature; some argued that it was semiaquatic to varying degrees, hunting fish from margins water bodies, or perhaps while wading swimming on surface; others suggest fully aquatic underwater pursuit predator. various proposals are based equally disparate lines evidence. A recent study by Fabbri coworkers sought resolve matter applying statistical method phylogenetic flexible discriminant analysis femur rib bone diameters microanatomy metric called global compactness. From their analyses datasets wide range extant extinct taxa, they concluded two ( S . , Baryonyx walkeri ) were submerged “subaqueous foragers,” whereas third Suchomimus tenerensis remained terrestrial We performed thorough reexamination datasets, analyses, methodological assumptions which those conclusions based, reveals substantial problems each these areas. In exemplar we found unsupported categorization lifestyle, inconsistent inclusion exclusion inappropriate choice taxa independent variables. also explored effects uncontrolled sources variation estimates compactness arise biological factors measurement error. ability draw quantitative is limited when represented single data points with potentially large intrinsic variability. results our show low accuracy applied distributions do not meet fundamental method. These findings only invalidate particular et al but implications future uses paleontology.
Language: Английский
Citations
7
Palaeontology, Journal Year: 2023, Volume and Issue: 66(3)
Published: May 1, 2023
Abstract A prominent hypothesis in the diversification of placental mammals after Cretaceous–Palaeogene (K/Pg) boundary suggests that extinction non‐avian dinosaurs resulted ecological release mammals, which were previously constrained to small body sizes and limited species richness. This ‘dinosaur incumbency hypothesis’ may therefore explain increases mammalian diversity via expansion into larger size niches, occupied by dinosaurs, but does not directly predict other classes. To evaluate this, we estimate sampling‐standardized patterns terrestrial North American fossil within classes, during Cretaceous Palaeogene. We find strong evidence for post‐extinction all Increases small‐bodied (less than 100 g, common class much smaller smallest non‐avialan ( c . 400 g)) similar those species. propose had access greater energetic resources or able partition more finely K/Pg mass extinction. is likely be result a combination widespread niche clearing due extinctions, alongside suite biotic abiotic changes occurred Late across boundary, such as shifting floral composition, novel key innovations among eutherian mammals.
Language: Английский
Citations
11
Historical Biology, Journal Year: 2025, Volume and Issue: unknown, P. 1 - 12
Published: March 31, 2025
Language: Английский
Citations
0
Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2021, Volume and Issue: 377(1844)
Published: Dec. 27, 2021
Early mammals were small and nocturnal. Their visual systems had regressed they poor vision. After the extinction of dinosaurs 66 mya, some but not all escaped ‘nocturnal bottleneck’ by recovering high-acuity By contrast, early primates bottleneck within age having large forward-facing eyes acute vision while remaining We propose that these differed from other changing balance between two sources information to cortex. Thus, cortical processing became less dependent on a relay superior colliculus (SC) temporal cortex more distributed primary (V1). In addition, major classes retina highly segregated into magnocellular (M cell) projections V1 primate-specific area (MT), parvocellular-dominated dorsolateral (DL or V4). The greatly expanded P cell inputs informed ventral stream involving frontal M pathways SC dorsal MT, surrounding cortex, parietal–frontal sensorimotor domains. This article is part theme issue ‘Systems neuroscience through lens evolutionary theory’.
Language: Английский
Citations
25
Current Biology, Journal Year: 2022, Volume and Issue: 32(7), P. 1629 - 1634.e2
Published: March 2, 2022
Language: Английский
Citations
17
The Anatomical Record, Journal Year: 2024, Volume and Issue: unknown
Published: Aug. 28, 2024
Members of the dinosaur clade Spinosauridae had numerous traits attributed to feeding in or around water, and their apparatus has often been considered analogous modern crocodylians. Here we quantify craniodental morphology compare it Crocodylia. We measured from spinosaurid crocodylian skeletal material area alveoli as a proxy for tooth size determine size-heterodonty. Geometric morphometrics were also conducted on crowns bearing regions skull. Spinosaurids overall relatively large alveoli, both they, crocodylians, isolated enlarged alveoli. Spinosaurines along caudal dentary that baryonychines lacked, which instead additional positions. Size-heterodonty was positively allometric, spinosaurids overlapped with generalist/macro-generalist crocodylians similar sizes. Spinosaurid crown shape morphologies certain slender-longirostrine yet lacked molariform distal typical most rostra mandibles deep undulating margins correlating local sizes, may indicate developmental constraint. particularly long concavity rosette anterior cranial teeth, corresponding bulbous rostral dentary. The well suited quickly striking creating punctures, but not cutting flesh durophagy. jaws interlocked secure prey move deeper into mouth. probably did little oral processing, spinosaurines could have processed vertebrates. Overall, there is no indication restricted fish small aquatic prey.
Language: Английский
Citations
3
Journal of Developmental Biology, Journal Year: 2025, Volume and Issue: 13(1), P. 9 - 9
Published: March 10, 2025
Stressors such as injuries, embryonic instability during development, and higher levels of stress hormones testosterone can result in increases fluctuating asymmetry reptiles other vertebrates. Digit asymmetry, digit ratio variability, skull trait eye jaw size have been correlated with level both snakes lizards. Teeth has also used a biomarker for brain laterality. Body is many potential stressors, yet there little research on how body relates to asymmetry. We investigate teeth within the lizard family Varanidae, clade diverse range sizes consisting largest living lizard, Varanus komodoensis. Using landmark/semi-landmark analysis, we derived Centroid Size 671 pairs from 13 varanid species, was each pair. Right-biased significantly greater upper tooth row, but breaking up positions into further sections did not yield significant difference. found positive linear correlation between right-biased directional Varanus, only when excluding V. This may fewer predators more food items, thus resulting less overall stress. When analyzed separately, komodoensis individuals <180 mm head length demonstrated positive, non-significant, trend along similar trajectory their congenerics high goodness fit. On hand, > 180 showed degree scatter, several specimens having pronounced left-biased suspect that this dramatic change due combination ontogenetic niche shift, bigger home ranges, susceptibility negative anthropogenic influences, and/or male bias sampled, larger sample required determine if statistical significance these intra-specific trends. reflect laterality, which be driver seen here.
Language: Английский
Citations
0
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