Phylogenetic analysis of Gondwanan basal eusauropods from the Early-Middle Jurassic of Patagonia, Argentina

Holwerda, Femke M.; Pol, Diego

doi:10.7203/sjp.33.2.13604

Cited by 9 publications

(7 citation statements)

References 55 publications

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“…As alluded to above, the level of development of the dorsal-head/caudal-middle-cerebral vein system has also a bearing on our appreciation of the phylogenetic position of FAM 03.064. This structure is particularly elaborated in Spinophorosaurus nigerensis (Knoll et al, 2012: figs 4A, B, D, S1, S2, S3), which is likely a basal sauropod (Holwerda & Pol, 2019). Generally speaking, it is well developed in sauropods (see e.g., Witmer et al, 2008), including non-titanosaurian titanosauriforms such as G. brancai (Knoll & Schwarz-Wings, 2009: figs 1, 2A, B, C, D) and Tambatitanis amicitiae (Saegusa & Ikeda, 2014: fig.…”

Section: Discussionmentioning

confidence: 99%

First palaeoneurological study of a sauropod dinosaur from France and its phylogenetic significance

Knoll

Lautenschlager

Valentin

et al. 2019

PeerJ

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Despite continuous improvements, our knowledge of the palaeoneurology of sauropod dinosaurs is still deficient. This holds true even for Titanosauria, which is a particularly speciose clade of sauropods with representatives known from numerous Cretaceous sites in many countries on all continents. The data currently available regarding the palaeoneurology of titanosaurs is strongly biased towards Gondwanan forms (Argentina above all, but also India, Malawi and Australia). In contrast, the palaeoneurology of Laurasian titanosaurs is known only from a few taxa from Spain and Uzbekistan, despite the discovery in other countries of Laurasia of a number of neurocranial remains that would lend themselves well to investigations of this kind. To fill in this gap in our knowledge, we subjected a titanosaurian braincase from the uppermost Upper Cretaceous of southern France to X-ray computed tomographic scanning, allowing the generation of 3D renderings of the endocranial cavity enclosing the brain, cranial nerves and blood vessels, as well as the labyrinth of the inner ear. These reconstructions are used to clarify the phylogenetic position of the specimen from the Fox-Amphoux-Métisson site. A combination of characters, including the presence of two hypoglossal rami on the endocast, the average degree of development of the dorsal-head/caudal-middle-cerebral vein system and the relatively short and subequal lengths of the ipsilateral semicircular canals of the labyrinth, are particularly revealing in this respect. They suggest that, compared with the few other Laurasian titanosaurs for which in-depth palaeoneurological data are available, the French taxon is more derived than the distinctly more ancient, possibly non-lithostrotian titanosaur from the Uzbek site of Dzharakuduk but more basal than derived saltasaurids, such as the coeval or slightly more recent forms from the Spanish locality of Lo Hueco.

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Section: Discussionmentioning

confidence: 99%

First palaeoneurological study of a sauropod dinosaur from France and its phylogenetic significance

Knoll

Lautenschlager

Valentin

et al. 2019

PeerJ

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“…The taxa belonging to the clade Sauropoda (in red) are examined in this study compared to taxa belonging to non‐sauropodiform sauropodomorphs (in green) and non‐sauropodan sauropodiforms (in yellow) grades. Based on phylogenies of Holwerda and Pol ( 2018 ) and Peyre de Fabrègues and Allain ( 2019 ). Taxa marked with an asterisk were added informally to the consensus of these two phylogenies (see Section 2 ).…”

Section: Introductionmentioning

confidence: 99%

A path to gigantism: Three‐dimensional study of the sauropodomorph limb long bone shape variation in the context of the emergence of the sauropod bauplan

Lefebvre

Houssaye

Mallison³

et al. 2022

Journal of Anatomy

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Sauropodomorph dinosaurs include the largest terrestrial animals that ever lived on Earth. The early representatives of this clade were, however, relatively small and partially to totally bipedal, conversely to the gigantic and quadrupedal sauropods. Although the sauropod bauplan is well defined, notably by the acquisition of columnar limbs, the evolutionary sequence leading to its emergence remains debated. Here, we aim to tackle this evolutionary episode by investigating shape variation in the six limb long bones for the first time using three‐dimensional geometric morphometrics. The morphological features of the forelimb zeugopod bones related to the sauropod bauplan tend to appear abruptly, whereas the pattern is more gradual for the hindlimb zeugopod bones. The stylopod bones tend to show the same pattern as their respective zeugopods. The abrupt emergence of the sauropod forelimb questions the locomotor abilities of non‐sauropodan sauropodomorphs inferred as quadrupeds. Features characterizing sauropods tend to corroborate a view of their locomotion mainly based on stylopod retraction. An allometric investigation of the shape variation in accordance with size highlight differences in hindlimb bone allometries between the sauropods and the non‐sauropodan sauropodomorphs. These differences notably correspond to an unexpected robustness decrease trend in the sauropod hindlimb zeugopod. In addition to forelimb bones that appear to be proportionally more gracile than in non‐sauropodan sauropodomorphs, sauropods may have relied on limb architecture and features related to the size increase, rather than general robustness, to deal with the role of weight‐bearing.

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“…The femur of Early Jurassic sauropod taxon Barapasaurus tagorei has closer proportions to NMS G.2020.10.1 (Table 1; Fig. 5b, c), suggesting that if NMS G.2020.10.1 is a sauropod femur, it belonged to a gracile taxon, and possibly not a cetiosaurid -Barapasaurus is currently placed outside of the cetiosaurid clade (Holwerda & Pol 2018). If NMS G.2020.10.1 belongs to a sauropod, we consider it most likely to be a fibula, as they are similar in length-to-width ratio to NMS G.2020.10.1 (Table 1).…”

Section: Sauropodamentioning

confidence: 98%

“…The femur of Early Jurassic sauropod taxon Barapasaurus tagorei has closer proportions to NMS.Eigg.2017 (Table 1, Fig. 5B-C), suggesting that if NMS.Eigg.2017 is a sauropod femur it belonged to a gracile taxon, and possibly not a cetiosaurid-Barapasaurus is currently placed outside of the cetiosaurid clade (Holwerda & Pol 2018).…”

Section: Sauropodamentioning

confidence: 98%

First dinosaur from the Isle of Eigg (Valtos Sandstone Formation, Middle Jurassic), Scotland

Panciroli

Funston

Holwerda

et al. 2020

Earth and Environmental Science Transactions of the Royal Society of Edinburgh

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Dinosaur body fossil material is rare in Scotland, previously known almost exclusively from the Great Estuarine Group on the Isle of Skye. We report the first unequivocal dinosaur fossil from the Isle of Eigg, belonging to a Bathonian (Middle Jurassic) taxon of uncertain affinity. The limb bone NMS G.2020.10.1 is incomplete, but through a combination of anatomical comparison and osteohistology, we determine it most likely represents a stegosaur fibula. The overall proportions and cross-sectional geometry are similar to the fibulae of thyreophorans. Examination of the bone microstructure reveals a high degree of remodelling and randomly distributed longitudinal canals in the remaining primary cortical bone. This contrasts with the histological signal expected of theropod or sauropod limb bones, but is consistent with previous studies of thyreophorans, specifically stegosaurs. Previous dinosaur material from Skye and broadly contemporaneous sites in England belongs to this group, including Loricatosaurus and Sarcolestes and a number of indeterminate stegosaur specimens. Theropods such as Megalosaurus and sauropods such as Cetiosaurus are also known from these localities. Although we find strong evidence for a stegosaur affinity, diagnostic features are not observed on NMS G.2020.10.1, preventing us from referring it to any known genera. The presence of this large-bodied stegosaur on Eigg adds a significant new datapoint for dinosaur distribution in the Middle Jurassic of Scotland.

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Phylogenetic analysis of Gondwanan basal eusauropods from the Early-Middle Jurassic of Patagonia, Argentina

Cited by 9 publications

References 55 publications

First palaeoneurological study of a sauropod dinosaur from France and its phylogenetic significance

First palaeoneurological study of a sauropod dinosaur from France and its phylogenetic significance

A path to gigantism: Three‐dimensional study of the sauropodomorph limb long bone shape variation in the context of the emergence of the sauropod bauplan

First dinosaur from the Isle of Eigg (Valtos Sandstone Formation, Middle Jurassic), Scotland

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