The neuroanatomy and pneumaticity of Hamadasuchus (Crocodylomorpha, Peirosauridae) from the Cretaceous of Morocco and its paleoecological significance for altirostral forms

Journal of Anatomy, Год журнала: 2023, Номер 243(3), С. 374 - 393

Опубликована: Июнь 13, 2023

We describe the endocranial structures of Hamadasuchus, a peirosaurid crocodylomorph from late Albian-Cenomanian Kem group Morocco. The cranial endocast, associated nerves and arteries, endosseous labyrinths, pneumatization, as well bones braincase new specimen, are reconstructed compared with extant fossil crocodylomorphs, which represent different lifestyles. Cranial this specimen identified belonging to close affinities Rukwasuchus yajabalijekundu, another 'middle' Cretaceous Tanzania. comparable those R. yajabalijekundu but also baurusuchids sebecids (sebecosuchians). Paleobiological traits such alert head posture, ecology, behavior explored for first time, using quantitative metrics. expanded narrow semi-circular canals enlarged pneumatization skull Hamadasuchus linked terrestrial lifestyle. Continuing work on neuroanatomy supposedly crocodylomorphs needs be broadened other groups will allow characterize whether some internal affected by lifestyle these organisms.

Язык: Английский

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A review of the non‐semiaquatic adaptations of extinct crocodylomorphs throughout their fossil record

The Anatomical Record, Год журнала: 2024, Номер 308(2), С. 266 - 314

Опубликована: Ноя. 25, 2024

Abstract Crocodylomorphs constitute a clade of archosaurs that have thrived since the Mesozoic until today and survived numerous major biological crises. Contrary to historic belief, their semiaquatic extant representatives (crocodylians) are not living fossils, and, during evolutionary history, crocodylomorphs evolved live in variety environments. This review aims summarize non‐semiaquatic adaptations (i.e., either terrestrial or fully aquatic) different groups from periods, highlighting how exactly those lifestyles inferred for animals, with regard geographic temporal distribution phylogenetic relationships. The ancestral condition Crocodylomorpha seems been lifestyle, linked several morphological such as an altirostral skull, long limbs allowing erect posture specialized dentition diets based on land. However, some members this clade, thalattosuchians dyrosaurids display opposite, aquatic interestingly same type observations. Finally, new techniques inferring paleobiology extinct animals put forward last decade, appearing complementary approach traditional descriptions comparisons. Such is case paleoneuroanatomical (CT scan data), histological, geochemical studies.

Язык: Английский

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An almost complete cranium of Asoriculus gibberodon (Petényi, 1864) (Mammalia, Soricidae) from the early Pliocene of the Jradzor site, Armenia

Swiss Journal of Palaeontology, Год журнала: 2025, Номер 144(1)

Опубликована: Апрель 14, 2025

Abstract We describe an almost complete fossil cranium of a shrew, identified as Asoriculus gibberodon (Petényi, 1864) from the early Pliocene Jradzor site, Armenia. The sedimentary unit, which yielded specimen, is 11-m-thick package composed white thinly-parallel-laminated diatomite laying at base section. It was dated 4.29 ± 0.09 Ma based on magnetostratigraphy and 40 Ar/ 39 Ar radioisotopic dating tephra layer located top package. skull shows several synapomorphies that allow its assignment to Soricinae subfamily Neomyini tribe. Among Neomyini, far anatomy known, specimen most similar Soriculus Episoriculus . Both petrosal bones are preserved studied thanks 3D modelling their morphology CT-scan. Compared with other eulipotyphlans, bony labyrinth A. typical soricids. Its also indicates high-frequency auditory capability modern shrews but cannot confirm echolocation system neither does it any feature can be related specific locomotory adaption or ecological characteristic. discovery this inside diatomites, corresponding distal lacustrine environment, raises question possible semi-aquatic adaptation species (this being known for extant family). However, , two genera closest cranial not clearly distinguished Neomys shrews. inner ear more terrestrial despite general similarities among soricids suggests echolocation-based orientation using high frequencies navigate through low vegetation, often essential in metabolic rate organisms reduce energy expenditure. therefore propose locomotion consistent previously proposed paleoecological model, depicting inhabiting wet humid environments close proximity permanent bodies water.

Язык: Английский

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Cranial and mandibular anatomy of Plastomenus thomasii and a new time-tree of trionychid evolution

Swiss Journal of Palaeontology, Год журнала: 2023, Номер 142(1)

Опубликована: Март 16, 2023

Abstract Trionychid (softshell) turtles have a peculiar bauplan, which includes shell reductions and cranial elongation. Despite rich fossil record dating back to the Early Cretaceous, evolutionary origin of trionychid bauplan is poorly understood, as even old fossils show great anatomical similarities extant species. Documenting structural detail trionychids may help resolve history group. Here, we study mandibular anatomy Plastomenus thomasii using µCT scanning. belongs Plastomenidae , long-lived (Santonian–Eocene) clade with uncertain affinities among subclades. The skulls known plastomenids are characterized by unusual features otherwise not trionychids, such extremely elongated, spatulate symphyses. We use observations for updated phylogenetic analyses both parsimony Bayesian methods. There strong support across methods stem-cyclanorbine plastomenids. inclusion stratigraphic data in our analysis indicates that range Cretaceous Asian including Perochelys lamadongensis be stem-trionychids, suggesting many evolved prior appearance crown Divergence time estimates from tip-dating Trionychia (134.0 Ma) Pan-Trionychidae (123.8 constrain span during has < 11 million years. rate estimation implies high morphological rates early softshell turtle evolution. If correct, partially fill gap results shallow divergence times cyclanorbines late Eocene.

Язык: Английский

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Paleoneurology of stem palaeognaths clarifies the plesiomorphic condition of the crown bird central nervous system

Journal of Morphology, Год журнала: 2024, Номер 285(6)

Опубликована: Май 17, 2024

Abstract Lithornithidae, an assemblage of volant Palaeogene fossil birds, provide our clearest insights into the early evolutionary history Palaeognathae, clade that today includes flightless ratites and tinamous. The neotype specimen Lithornis vulturinus , from Eocene (approximately 53 million years ago) Europe, a partial neurocranium has never been thoroughly investigated. Here, we describe these cranial remains including nearly complete digital endocasts brain bony labyrinth. telencephalon is expanded its optic lobes are ventrally shifted, as typical for crown birds. foramen magnum positioned caudally, rather than flexed in some with lobes, cerebellum, shifted further ventrally. overall shape similar to tinamous, only extant flying palaeognaths, suggesting several aspects tinamou neuroanatomy may have evolutionarily conserved since at least Cenozoic. estimated ratio lobe's surface area relative total suggests diurnal ecology. date ancestral bird, combining ancestrally unflexed caudally oriented connection spinal cord, moderately enlarged telencephalon, lobes.

Язык: Английский

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Ontogenetic variation in the crocodylian vestibular system

Journal of Anatomy, Год журнала: 2021, Номер 240(5), С. 821 - 832

Опубликована: Ноя. 28, 2021

Abstract Crocodylians today live in tropical to subtropical environments, occupying mostly shallow waters. Their body size changes drastically during ontogeny, as do their skull dimensions and bite forces, which are associated with prey preferences. Endocranial neurosensory structures have also shown change ontogenetically, but less is known about the vestibular system of inner ear. Here we use 30 high‐resolution computed tomography (CT) scans three‐dimensional geometric morphometrics investigate shape crocodylian endosseous labyrinths throughout across four stages (hatchling, juvenile, subadult adult). We find two major patterns ontogenetic change. First, labyrinth increases negative allometry relation size. Second, significantly, hatchlings having shorter semicircular canal radii, thicker diameters an overall dorsoventrally than those more mature individuals. argue that modification ontogeny related constraints imposed by growth, due fundamental braincase (e.g. verticalisation basicranium), rather locomotion, diet, or other biological functions behaviours.

Язык: Английский

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A new pelomedusoid turtle,Sahonachelys mailakavava, from the Late Cretaceous of Madagascar provides evidence for convergent evolution of specialized suction feeding among pleurodires

Royal Society Open Science, Год журнала: 2021, Номер 8(5)

Опубликована: Май 1, 2021

The Maevarano Formation in northwestern Madagascar has yielded a series of exceptional fossils over the course last three decades that provide important insights into evolution insular ecosystems during latest Cretaceous (Maastrichtian). We here describe new genus and species pelomedusoid turtle from this formation, Sahonachelys mailakavava , based on nearly complete skeleton. A phylogenetic analysis suggests close affinities with coeval Madagascan Sokatra antitra . These two taxa are only known representatives newly recognized clade Sahonachelyidae which is sister to speciose formed by Bothremydidae Podocnemidoidae relationship Indian turtles Kurmademydini notably absent. functional assessment was specialized suction feeder preyed upon small-bodied invertebrates vertebrates. This unique feeding strategy among crown pelomedusoids convergent documented numerous other clades highlights distinct evolutionary pathways taken

Язык: Английский

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Neuroanatomy of the late Cretaceous Thescelosaurus neglectus (Neornithischia: Thescelosauridae) reveals novel ecological specialisations within Dinosauria

Scientific Reports, Год журнала: 2023, Номер 13(1)

Опубликована: Ноя. 6, 2023

Abstract Ornithischian dinosaurs exhibited a diversity of ecologies, locomotory modes, and social structures, making them an ideal clade in which to study the evolution neuroanatomy behaviour. Here, we present 3D digital reconstruction endocranial spaces latest Cretaceous neornithischian Thescelosaurus neglectus , order interpret paleobiology one last surviving non-avian dinosaurs. Results demonstrate that brain was relatively small compared most other neornithischians, instead suggesting cognitive capabilities within range extant reptiles. Other traits include narrow hearing range, with limited ability distinguish high frequencies, paired unusually well-developed olfactory lobes anterior semicircular canals, indicating acute olfaction vestibular sensitivity. This character combination, conjunction features postcranial anatomy, is consistent specializations for burrowing behaviours clade, as evidenced by trace skeletal fossil evidence earlier-diverging thescelosaurids, although whether they reflect ecological adaptations or phylogenetic inheritance T. itself unclear. Nonetheless, our results provide first neurological identified Ornithischia, more generally, expanding recognized this major clade.

Язык: Английский

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Neuroanatomy and pneumaticity of the extinct Malagasy “horned” crocodile Voay robustus and its implications for crocodylid phylogeny and palaeoecology

The Anatomical Record, Год журнала: 2023, Номер 307(8), С. 2749 - 2786

Опубликована: Дек. 20, 2023

Abstract Voay robustus , the extinct Malagasy “horned” crocodile, was originally considered to be only crocodylian representative in Madagascar during most part of Holocene. However, remains have had confused taxonomic attributions and recent studies underlined that Crocodylus populations coexisted on island for at least 7500 years. Here, we describe inner braincase anatomy using x‐ray computed tomography four specimens, provide new anatomical information distinguishes from especially features brain endocast paratympanic sinuses. Geometric morphometric analyses are performed 3D models internal organs compare statistically with a subset extant Crocodylidae. Following these comparisons, build an endocranial morphological matrix discuss proposed phylogenetic affinities Osteolaeminae point view. Additionally, use characters systematic find they can major impact analyses. Finally, radiocarbon data subfossil specimens recovered between 2010 2750 cal BP, which confirm cohabitation two species same area long period time. We thus assess several extinction scenarios, propose slightly different ecology compared could allowed habitat partitioning island. Our approach complements obtained previous molecular phylogenies, as well dating, together revealing past diversity faunal turnovers Madagascar.

Язык: Английский

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Reevaluation of the cranial osteology and phylogenetic position of the early crocodyliform Eopneumatosuchus colberti , with an emphasis on its endocranial anatomy

The Anatomical Record, Год журнала: 2021, Номер 305(10), С. 2557 - 2582

Опубликована: Окт. 22, 2021

Abstract Eopneumatosuchus colberti Crompton and Smith, 1980, known from a single partial skull, is an enigmatic crocodylomorph the Lower Jurassic Kayenta Formation. In spite of its unique morphology, exceptionally pneumatic braincase, presence during critical time period evolution, relatively little about this taxon. Here, we redescribe external cranial morphology E . , present novel information on endocranial anatomy, evaluate phylogenetic position among early crocodylomorphs, seek to better characterize ecology. Our examination clarifies key aspects suture paths braincase anatomy. Comparisons with related taxa (e.g., Protosuchus haughtoni ) demonstrate that extreme pneumaticity may be more widespread in protosuchids than previously appreciated. Computed tomography scans reveal resembles other particular noncrocodyliform Almadasuchus figarii There are, however, differences olfactory bulb cerebral hemisphere which endocranium crocodylomorphs not as conserved hypothesized. analysis recovers close relative richardsoni Edentosuchus tienshanensis contrasting previous hypotheses sister group relationship Thalattosuchia. Previous work suggested inner ear has some similarities semi‐aquatic crocodyliforms, but placement terrestrial postcranial skeletal complicates paleoecological interpretation.

Язык: Английский

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