Body size estimation of Caimaninae specimens from the Miocene of South America

Paiva, Ana Laura S.; Godoy, Pedro; Souza, Ray Brasil Bueno de; Klein, Wilfried; Hsiou, Annie Schmaltz

doi:10.1016/j.jsames.2022.103970

Cited by 11 publications

(5 citation statements)

References 65 publications

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“…As a result, we completed the dataset of Dumont Jr et al (2020; Figure 8), which rather uses the raw log‐transformed measurements of body and brain mass (Figure 8; see also Data S1). Body mass is estimated from skull measurements in fossil specimens using linear regression between those metrics in extant crocodylians (Paiva et al, 2022). Brain mass can be derived from the endocranial volume (assuming a brain density of 1) from the following relation:

\log italicBV = \log italicEV * 0.7279 + 0.75624

where EV: endocranial volume and BV: brain volume (Dumont Jr et al, 2020 and references therein).…”

Section: Discussionmentioning

confidence: 99%

“…As a result, we completed the dataset of Dumont Jr et al (2020; Figure8), which rather uses the raw log-transformed measurements of body and brain mass (Figure8; see also Data S1). Body mass is estimated from skull measurements in fossil specimens using linear regression between those metrics in extant crocodylians(Paiva et al, 2022). Brain mass can be derived from the endocranial volume (assuming a brain density of 1) from the following relation: logBV = logEV * 0.7279 + 0.75624 F I G U R E 7 Three-dimensional reconstructions of the endosseous labyrinths of different reptiles in lateral view: (a) Hamadasuchus (right, UCBL FSL 532408); (b) Zulmasuchus querejazus (left, MHNC 6672 from Pochat-Cottilloux et al, 2021); (c) Crocodylus porosus (left, OUVC 10899); (d) Viavenator exxoni (left, MAU-Pv-Li-530 from Paulina-Carabajal & Filippi, 2018); (e) Baurusuchus sp.…”

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confidence: 99%

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

et al. 2023

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

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\log italicBV = \log italicEV * 0.7279 + 0.75624

where EV: endocranial volume and BV: brain volume (Dumont Jr et al, 2020 and references therein).…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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

et al. 2023

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“…The remarkable differences in size between some species (e.g., A. minuta vs. Macranhinga) are probably, to some extent, explained by diet-related niche partitioning. The higher levels of diversity, size disparity, and sympatry of Miocene anhingids in South America are mirrored and surpassed by the fossil record of crocodylians (Paiva et al, 2022;Salas-Gismondi et al, 2015;Scheyer et al, 2013). Interestingly, the impoverishment of both group's diversity is coincidental to post-Miocene climatic deterioration in the south (e.g., Cenizo & Agnolin, 2010;Diederle & Agnolin, 2017) and significant landscape modifications in the north triggered by the Andean orogeny, which culminated in the predominance of fluvial environments (e.g., Cidade et al, 2019;Riff et al, 2010;Salas-Gismondi et al, 2015).…”

Section: Phylogenetic Inferencementioning

confidence: 99%

New fossil anhingids from the upper Acre River (Late Miocene of southwestern Amazon)

Guilherme,

D'Apolito,

Muniz

et al. 2023

The Anatomical Record

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Four extant species of anhingids are found worldwide, all belonging to a single genus (Anhinga). However, the fossil record reveals a much greater diversity of this group in the past. The oldest known anhingids date back to the upper Oligocene period in Australia, but during the Miocene epoch in South America, they achieved their most remarkable diversity. This study describes newly discovered anhingid fossils from the Late Miocene period in South America. These fossils were extracted from the Acre conglomerate member, part of the Upper Miocene deposits in the southwestern Amazon region. The described fossils consist of two fragments of pelvic girdles, two femora, and two vertebrae belonging to a giant anhingid (Macranhinga sp.), as well as a vertebra from Anhinga minuta, the smallest of all darters. The examination of these fossils suggests the presence of potentially three distinct anhingid taxa within the same locality. The environment in which the conglomerate deposits were formed was ecologically complex. It is likely that these three species coexisted within the same ecosystem but avoided direct competition for food and reproductive sites by not fully exploiting their fundamental niche.

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“…Kubo & Benton 2009; Zanno & Makovicky 2011; Iijima 2017; Paiva et al . 2022). There have been multiple recent studies examining relative growth rates in extant crocodylians, focusing on skull and body lengths (Webb et al .…”

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confidence: 99%

Evaluating growth in Macrospondylus bollensis (Crocodylomorpha, Teleosauroidea) in the Toarcian Posidonia Shale, Germany

Johnson,

Amson,

Maxwell

2023

Papers in Palaeontology

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The study of how organisms grow is a fundamental aspect of palaeontology. Growth in teleosauroids is poorly understood and little studied, especially in an ontogenetic sense. We investigate growth rates of the most common and abundant teleosauroid, Macrospondylus bollensis, in which a large sample of multiple body sizes is available from the Posidonienschiefer Formation (Posidonia Shale) of southwestern Germany. We perform linear regression analyses on 62 specimens of Macrospondylus (16 juveniles, 7 subadults and 39 adults) using 21 cranial and postcranial measurements. Our results show that juvenile, subadult and adult individuals have near‐isometric or isometric growth throughout much of the body. Notably, we find that in Macrospondylus: (1) the femur grows at a faster rate than the skull and hindlimb zeugopodium; (2) the forelimb and hindlimb grow at the same rate; and (3) there is distinct ontogenetic signal in the growth of the orbit and supratemporal fenestra. We also find that limb scaling in Macrospondylus is somewhat comparable to that seen in the extant gavialids Gavialis gangeticus and Tomistoma schlegelii. Last, we examine evolutionary allometry in skull length relative to body size in Crocodylomorpha using femoral length as a proxy, which shows a near‐isometric trend. Non‐thalattosuchian crocodylomorphs (with the exception of one pholidosaurid and one dryosaurid taxon) are differentiated from thalattosuchians due to their shorter skulls, as previously suggested, but the scaling relationship with femur length remains unchanged.

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Body size estimation of Caimaninae specimens from the Miocene of South America

Cited by 11 publications

References 65 publications

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

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

New fossil anhingids from the upper Acre River (Late Miocene of southwestern Amazon)

Evaluating growth in Macrospondylus bollensis (Crocodylomorpha, Teleosauroidea) in the Toarcian Posidonia Shale, Germany

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