Current Biology, Journal Year: 2023, Volume and Issue: 33(3), P. R103 - R106
Published: Feb. 1, 2023
Language: Английский
The Anatomical Record, Journal Year: 2024, Volume and Issue: 307(4), P. 1559 - 1593
Published: Jan. 10, 2024
Abstract The complex constructions of land vertebrate skulls have inspired a number functional analyses. In the present study, we provide basic view on skull biomechanics and offer framework for more general observations using advanced modeling approaches in future. We concentrate our discussion cranial openings temporal region work out two major, feeding‐related factors that largely influence shape skull. argue (1) place where most forceful biting is conducted (2) handling resisting food (sideward movements) constitute formation shaping either one or arcades surrounding these openings. Diversity anatomy among amniotes can be explained by specific modulations with different amounts acting forces which inevitably lead to deposition reduction bone material. For example, anterior bite favors an infratemporal bar, whereas posterior upper arcade. Transverse (inertia resistance seized objects) as well neck posture also region. Considering their individual morphotypes, finally hypotheses feeding adaptation variety major tetrapod groups. did not consider ligaments, internal structure, kinesis considerations. Involving those quantitative tests hypotheses, such finite element system synthesis, will comprehensive picture mechanics evolution
Language: Английский
Citations
6
The Anatomical Record, Journal Year: 2024, Volume and Issue: 307(12), P. 3717 - 3781
Published: July 9, 2024
Thescelosaurines are a group of early diverging, ornithischian dinosaurs notable for their conservative bauplans and mosaic primitive features. Although abundant within the latest Cretaceous ecosystems North America, record is poor to absent in earlier assemblages, leaving large gap our understanding evolution, origins, ecological roles. Here we report new small bodied thescelosaurine-Fona herzogae gen. et sp. nov.-from Mussentuchit Member Cedar Mountain Formation, Utah, USA. Fona represented by multiple individuals, representing one most comprehensive skeletal assemblages bodied, diverging described from America date. Phylogenetic analysis recovers as earliest member Thescelosaurinae, minimally containing Oryctodromeus, all three species Thescelosaurus, revealing clade was well-established Cenomanian, distinct from, yet continental cohabitants with, sister clade, Orodrominae. To date, orodromines thescelosaurines have not been found together single American ecosystem, suggesting different habitat preferences or competitive exclusion. Osteological observations reveal extensive intraspecific variation across cranial postcranial elements, number anatomical similarities with shared semi-fossorial lifestyle.
Language: Английский
Citations
6
Journal of Systematic Palaeontology, Journal Year: 2023, Volume and Issue: 21(1)
Published: Jan. 1, 2023
The armoured dinosaurs (Thyreophora) were a significant component of Mesozoic terrestrial ecosystems, appearing in the earliest Jurassic and surviving until latest Cretaceous, fossils group have been found on all continents, including Antarctica. However, patchy fossil record highly modified anatomy has hindered reconstruction their evolutionary history. For example, relationships many early-diverging taxa are labile degree convergence between two major clades, Ankylosauria Stegosauria, difficult to assess. There never species-level phylogenetic analysis thyreophoran dinosaurs; recently, computational ability analyse such dataset did not exist and, consequently, interrelationships within debated. Here, we address these issues with new that includes majority named (340 characters, 91 taxa). This was analysed using equal- implied-weights parsimony Bayesian inference, further explored constraint trees partitioned datasets. Stratigraphical congruence used identify 'preferred tree' analyses reveal novel hypothesis for relationships. traditional ankylosaurian dichotomy is supported: instead, four distinct ankylosaur clades identified, long-standing 'traditional' clade Nodosauridae rendered paraphyletic. Ankylosauridae, Panoplosauridae, Polacanthidae Struthiosauridae morphotypes, typified by Euoplocephalus, Edmontonia/Panoplosaurus, Gastonia Struthiosaurus, respectively. Isaberrysaura an early stegosaur Scelidosaurus non-eurypodan. Many characters related feeding quadrupedality coincident diversification Eurypoda. Unstable generally incomplete but other better-known also unstable, suggesting need taxonomic revisions. Partitioned datasets show high postcrania osteoderm do contain strong signal.
Language: Английский
Citations
12
Journal of Anatomy, Journal Year: 2025, Volume and Issue: unknown
Published: March 21, 2025
Unlike mammals, reptiles typically lack large muscles and ligaments that connect the zygoma to mandible. Dinosaur craniomandibular soft tissue reconstructions, often based on rationale of extant phylogenetic bracketing, follow this general rule. However, descending flanges from zygomata hadrosaurs, heterodontosaurids, psittacosaurids have been used argue for a masseter-like muscle in these dinosaur taxa. We examined dinosauriform skulls osteological indicators connective entheses mandible, subsequently sectioned 10 specimens histological evidence. Osteological were found most sampled dinosauriforms, which range rugosities processes, morphologically resemble known muscular ligamentous entheses. Similarly, rugose features oriented towards mandible many having previously interpreted as adductor mandibulae group. Serial sectioning ceratopsid, hadrosaurid, tyrannosaurid jugal surangular reveals an external cortex rich collagen fibres, strongly resembling entheseal fibres. Jugal fibres are usually ventrally surangular, hadrosaurids tyrannosaurids parallel macroscopic striations surfaces flange. Histological sections chicken buccal regions show similar attachments jugomandibular ligament musculature hypothesise strong structure bridging dinosaurs, termed 'exoparia'. This structure's size proximity joint would be advantageous stabilising relative cranium during jaw movement, particularly dinosaurs thought process their masticate. A or identity exoparia cannot determined with available data, but shape zygomatic more consistent attachment. Possible antecedents non-dinosauriform archosaurs derivations modern birds may exist, homology is currently unknown. These results highlight complex evolution caution against simplified model-based approaches reconstruction ignore contrasting signals.
Language: Английский
Citations
0
Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2025, Volume and Issue: unknown
Published: May 8, 2025
ABSTRACT Diversity in the body shapes and sizes of dinosaurs was foundational to their widespread success during Mesozoic era. The ability quantify size form reliably is therefore critical study dinosaur biology evolution. Body mass estimates for any given fossil animal are, theory, most informative when derived from volumetric models that account three‐dimensional entire body. In addition providing total mass, approaches can be used determine inertial properties specific segments overall distribution throughout body, each which are essential modelling interpretation form–function relationships associations with ecology. However, determination volumes taxa often subjective, may sensitive varied artistic inference. This highlights need an approach estimation segment systematically constrained by quantitative scaling between hard tissues fossilise soft only observable extant taxa. To this end, we recently published skeletal tissue factors CT data sauropsids estimate 52 non‐avian representing majority major clades plans. masses estimated range less than 200 g tiny avialan Yixianornis over 60 tonnes giant sauropod Patagotitan , currently largest known mostly complete remains. From our models, infer many previous reconstructions envelopes too small, were heavier estimates. Our generally overlap limb bone shaft dimensions, but considerable variability among clades. suggests different either differed volume ratios, or dimensions relative perhaps related differences locomotor dynamics postural also allowed us investigate variation proportions across a perspective grounded anatomical data, framing long‐standing hypotheses about form, function, behaviour context. For example, reconstructed disparity whole‐body centres reflects broad array postures clades, while lack strong positive allometry weight‐bearing corroborates studies suggesting decrease performance as increased.
Language: Английский
Citations
0
BMC Ecology and Evolution, Journal Year: 2024, Volume and Issue: 24(1)
Published: April 16, 2024
Abstract Background Tooth replacement patterns of early-diverging ornithischians, which are important for understanding the evolution highly specialized dental systems in hadrosaurid and ceratopsid dinosaurs, poorly known. The neornithischian Jeholosaurus , a small, bipedal herbivorous dinosaur from Early Cretaceous Jehol Biota, is an taxon ornithischian evolution, but its morphology was only briefly described previously tooth Results CT scanning six specimens representing different ontogenetic stages reveals significant new information regarding system including one or two teeth nearly all alveoli, relatively complete resorption, increase numbers alveoli during ontogeny. Reconstructions Zahnreihen indicate that pattern maxillary dentition similar to dentary with cyclical difference. rate probably 46 days, faster than most other ornithischians. During ontogeny premaxillary slows 25 days 33 daily dentine formation. Conclusions exhibits decreasing trend ontogeny, as Alligator . In phylogenetic context, fast multi-generation have evolved at least twice independently Ornithopoda, our analyses suggest members major clades exhibit adaption herbivory.
Language: Английский
Citations
3
Communications Biology, Journal Year: 2024, Volume and Issue: 7(1)
Published: April 10, 2024
Abstract Oviraptorosaurians were a theropod dinosaur group that reached high diversity in the Late Cretaceous. Within oviraptorosaurians, later diverging oviraptorids evolved distinctive crania which extensively pneumatised, short and tall, had robust toothless beak, interpreted as providing powerful bite for their herbivorous to omnivorous diet. The present study explores ability of oviraptorid resist large mechanical stresses compared with other theropods where this adaptation originated within oviraptorosaurians. Digital 3D cranial models constructed earliest oviraptorosaurian, Incisivosaurus gauthieri , three oviraptorids, Citipati osmolskae Conchoraptor gracilis Khaan mckennai . Finite element analyses indicate oviraptorosaurian stronger than those ( Erlikosaurus Ornithomimus ) more comparable large, carnivorous Allosaurus biomechanics align indicating an early establishment strengthened Oviraptorosauria, even before highly modified morphology. Bite modelling, using estimated muscle forces, suggests may have functioned closer structural safety limits. Low around beaks suggest convergently evolved, functionally distinct rhamphotheca, serving cropping/feeding tool rather stress reduction, when theropods.
Language: Английский
Citations
2
Geological Society London Special Publications, Journal Year: 2023, Volume and Issue: 544(1)
Published: Oct. 25, 2023
Abstract Dinosaurs were thriving at the beginning of Cretaceous, and yet major changes had occurred across Jurassic–Cretaceous boundary. The sauropods replaced by ornithopods as dominant herbivores, which has been explained many ecological scenarios, including replacement gymnosperms angiosperms land plants. ornithischians went on to radiate substantially in mid Late with key clades (hadrosaurs, ceratopsians, ankylosaurs) specializing different feeding modes diets, reaching huge abundance faunas. New computational methods allow palaeobiologists assess aspects palaeobiology, macroecology macroevolution dinosaurs through Cretaceous testable repeatable ways. These new approaches have shed light mysteries, such whether ate flowers, why hadrosaurs so successful some theropods became larger or smaller, switched from carnivory herbivory. There are further debates around final demise dinosaurs, where regional global data suggest group was decline latter part before they finished asteroid impact.
Language: Английский
Citations
5
Palaeontology, Journal Year: 2024, Volume and Issue: 67(1)
Published: Jan. 1, 2024
Abstract Adaptation to specialist ecological niches is a key innovation that has contributed the evolutionary success of many vertebrate clades, underpinning acquisition diverse skull morphologies. Dinosaurs, which dominated Mesozoic terrestrial faunas, acquired herbivory multiple times, and evolution these herbivorous adaptations linked drastic changes in dental craniomandibular functional morphology, yet whether functionally relevant phenotypic traits occurred more rapidly lineages compared carnivorous remains largely untested statistical phylogenetic framework. Here, we infer rates using variable‐rate models on relative biting edge (tooth row) lengths 107 dinosaur taxa test hypothesis associated with rapid mandibular biomechanics. We find elevated biomechanical theropods foreshortened beaked skulls (Oviraptorosauria, Limusaurus ), as well ceratopsians Diplodocus . The presence position reduced tooth row increased jaw efficiency unite high‐rate lineages, indicating selection for greater Large departures from isometric scaling characteristics helps explain differences clades those other (Therizinosauria, Ornithomimosauria). Additionally, hypothesize extreme ontogenetic within species lifetimes may be behind some instances branch‐wise rates. Thus, show how exceptional can reveal signatures within‐species sequences.
Language: Английский
Citations
1
PeerJ, Journal Year: 2024, Volume and Issue: 12, P. e17764 - e17764
Published: Aug. 13, 2024
The basal macronarian sauropod
Language: Английский
Citations
1