New Data About the Presence and Absence of the External Fundamental System in Archosaurs

Andrade, Rafael César Lima Pedroso de; Bantim, Renan Alfredo Machado; Lima, Flaviana Jorge de; Campos, Leomir dos Santos; Eleutério, Lúcia Helena de Souza; Sayão, Juliana Manso

doi:10.14295/cad.cult.cienc.v14i1.932

Cited by 18 publications

(16 citation statements)

References 30 publications

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“…Ontogenetic stages are regarded here in the context of individual growth trajectories from juveniles to fully grown adults, as reflected in the degree of osteohistological maturity generalized over all sampled bones. Assessing the specimens’ ontogenetic stage is based on the combination of osteohistological characters that change over time and indicate the dynamics of diametric bone growth and maturation process 44 – 51 .…”

Section: Methodsmentioning

confidence: 99%

“…Adults are fully grown, skeletally mature individuals with bones showing complete cessation of, or only minimal, accretional diametric growth with avascular outermost cortex and often densely accumulated growth lines or lamellae referred to as external fundamental system (EFS) or outer circumferential layer (OCL), respectively 51 , 53 . As microdamage repair, calcium metabolism and biomechanical adaptations in the bone require secondary remodelling, which accumulates with age 54 – 56 , the listed primary features combined with extensive remodelling with several generations of secondary osteons often imply senescence.…”

Section: Methodsmentioning

confidence: 99%

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Intraskeletal histovariability, allometric growth patterns, and their functional implications in bird-like dinosaurs

Prondvai

Godefroit

Adriaens

et al. 2018

Sci Rep

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With their elongated forelimbs and variable aerial skills, paravian dinosaurs, a clade also comprising modern birds, are in the hotspot of vertebrate evolutionary research. Inferences on the early evolution of flight largely rely on bone and feather morphology, while osteohistological traits are usually studied to explore life-history characteristics. By sampling and comparing multiple homologous fore- and hind limb elements, we integrate for the first time qualitative and quantitative osteohistological approaches to get insight into the intraskeletal growth dynamics and their functional implications in five paravian dinosaur taxa, Anchiornis, Aurornis, Eosinopteryx, Serikornis, and Jeholornis. Our qualitative assessment implies a considerable diversity in allometric/isometric growth patterns among these paravians. Quantitative analyses show that neither taxa nor homologous elements have characteristic histology, and that ontogenetic stage, element size and the newly introduced relative element precocity only partially explain the diaphyseal histovariability. Still, Jeholornis, the only avialan studied here, is histologically distinct from all other specimens in the multivariate visualizations raising the hypothesis that its bone tissue characteristics may be related to its superior aerial capabilities compared to the non-avialan paravians. Our results warrant further research on the osteohistological correlates of flight and developmental strategies in birds and bird-like dinosaurs.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Intraskeletal histovariability, allometric growth patterns, and their functional implications in bird-like dinosaurs

Prondvai

Godefroit

Adriaens

et al. 2018

Sci Rep

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“…Sometimes, it is also possible to recognize a somewhat broad band in the periosteal zone, the external fundamental system (EFS). The EFS consists of an edge of slow-growing tissue without vascularization formed by parallel-fibred bone after maturity has been achieved (Chinsamy-Turan, 2005;Woodward et al 2013;de Andrade et al 2015). Bone tissue is sometimes interrupted by growth marks.…”

Section: Histological Analysismentioning

confidence: 99%

Calibration of life history traits with epiphyseal closure, dental eruption and bone histology in captive and wild red deer

et al. 2019

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The study of skeletochronology and bone tissue as a record of information on ontogenetic stages and events is widely used for improving the knowledge about life histories (LHs) of extinct and extant vertebrates. Compared with dinosaurs and extant reptiles, mammalian bone histology has received little attention. Here, we calibrate for the first time bone and dental age with histological bone characteristics and LH stages in ontogenetic series of red deer. We rely on known LHs of different aged individuals of captive Cervus elaphus hippelaphus from Austria to correlate epiphyseal closure, dental eruption pattern, bone growth marks and bone tissue patterns in femora and tibiae, and of wild Cervus elaphus hispanicus from Spain. Our data show that females (of both subspecies) attain skeletal maturity earlier than males. At this moment, epiphyseal closure (in femora and tibiae) and dental eruption are complete and long bones start to deposit an external fundamental system. The results also show that the attainment of reproductive maturity in red deer occurs slightly before skeletal maturity.

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“…When skeletal maturity is attained, the animal forms the External Fundamental System (EFS). This has been already detected in many clades of archosaurs (see 80 for a review). Specifically, in dinosaurs the EFS has been reported within many taxa 63,78,81,82 but has not been identified in Aratasaurus museunacionali.…”

Section: Discussionmentioning

confidence: 62%

The first theropod dinosaur (Coelurosauria, Theropoda) from the base of the Romualdo Formation (Albian), Araripe Basin, Northeast Brazil

Sayão

Saraiva

Brum

et al. 2020

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The Romualdo Formation (Araripe Basin) is worldwide known for the large number of well-preserved fossils but the dinosaur record is rather scarce. Here we describe a new coelurosaur, which is the first tetrapod recovered from the basal layers of this stratigraphic unit that consist of dark shales. Aratasaurus museunacionali gen. et sp. nov. is known by an incomplete but articulated right hind limb with the distal portion of the femur, proximal half of tibia and incomplete pes. The new species differs from other coelurosaurs by a medial fossa in the tibia and digits II, III and IV being symmetric. The phylogenetic analysis recovered Aratasaurus museunacionali closely related to Zuolong salleei, forming a basal coelurosaur lineage. The paleohistology indicate that the specimen is a juvenile, with an estimated body length around 3.12 m. The new taxon represents the first occurrence of basal coelurosaurians in the Araripe Basin and suggests a widespread distribution of this group during the Lower Cretaceous. The dinosaur record in Brazil is still quite meager compared to the potential of the country 1,2. So far, most specimens were recovered from the Bauru Group, including non-avian theropods 3,4,5,6,7. The latter are less numerous in these deposits than other reptiles 8 , leading to several discussions, including niche partitioning 7. The limited amount of theropod material is not exclusive of Brazil 9. Among the regions where such reptiles are found in the country is the Araripe Basin 10. This tectonic structure is worldwide known for the well preserved and diverse fossil biota 11,12,13,14. The most fossiliferous units are the Lower Cretaceous Crato and Romualdo formations, comprising the majority of fossil vertebrates of this basin 14. As has been reported several times, the most common tetrapod in both units are pterosaurs 15 , while others tend to be rare 16,17,18. Until now all non-avian dinosaur from the Araripe Basin came exclusively from the Romualdo Formation and are represented by the spinosaurids Irritator challengeri 19 and Angaturama limai 1 and the non-avian coelurosaurs Santanaraptor placidus 20,21 and Mirischia assymetrica 22. All were preserved in the level of carbonate concretions from the upper portion of this stratigraphic unit 14,23,24. Here we describe a new theropod dinosaur from the Romualdo Formation that was collected in the lower section. The fossil is preserved in a slab of dark shale, housed at the Museu de Paleontologia Plácido Cidade

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New Data About the Presence and Absence of the External Fundamental System in Archosaurs

Cited by 18 publications

References 30 publications

Intraskeletal histovariability, allometric growth patterns, and their functional implications in bird-like dinosaurs

Intraskeletal histovariability, allometric growth patterns, and their functional implications in bird-like dinosaurs

Calibration of life history traits with epiphyseal closure, dental eruption and bone histology in captive and wild red deer

The first theropod dinosaur (Coelurosauria, Theropoda) from the base of the Romualdo Formation (Albian), Araripe Basin, Northeast Brazil

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