New insights on metabolic rates and aerobic scopes of the tapejarid pterosaur Caiuajara dobruskii
Abstract
Studies on paleophysiology and thermoregulation are central topics in fossil vertebrate paleobiology because they allow inferences about extinct organismal function beyond anatomical description. Pterosaur thermophysiology remains actively debated. Evidence such as relatively rapid growth and elevated metabolic rate estimates has been used to argue for endothermic-like physiologies consistent with the energetic demands of powered flight, whereas reproductive traits, including burial incubation and precocial development, have led some authors to propose ectothermic strategies more akin to those of extant non-avian diapsids. Here, we provide quantitative estimates of resting metabolic rate (RMR) for the tapejarid pterosaur Caiuajara dobruskii using phylogenetic eigenvector maps and osteocyte lacunar density as proxy. Analysis of six histological sections from three appendicular elements (femur, tibia, humerus) at different ontogenetic stages (adult and juvenile) yielded mass-independent RMR estimates of 0.24–0.76 ml O 2 h −1 g −0.86 , substantially higher than those of lepidosaurs but lower than typical mammalian and avian values. The retrodicted mass-independent maximum metabolic rate (MMR) of 5.68 ml O 2 h −1 g −0.87 falls between values for highly active reptiles and birds, suggesting sufficient aerobic capacity to sustain powered flight without fully matching the maximal performance of small endotherms. Together, these results suggest active-flighted pterosaurs fall among a metabolically intermediate continuum, limiting straightforward actualistic comparisons for inferring their thermoregulatory strategy.
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BibTeX
@article{araujo2026insights,
title = {{New insights on metabolic rates and aerobic scopes of the tapejarid pterosaur Caiuajara dobruskii}},
author = {Esaú Victor De Araújo and Mariana Valeria Haase and Jorge Cubo and Luiz Carlos Weinschütz and Alexander Wilhelm Armin Kellner and Juliana Manso Sayão},
journal = {Paleobiology},
year = {2026},
month = sep,
doi = {10.1017/pab.2026.10111},
url = {https://hal.science/hal-05753329v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - New insights on metabolic rates and aerobic scopes of the tapejarid pterosaur Caiuajara dobruskii
AU - Esaú Victor De Araújo
AU - Mariana Valeria Haase
AU - Jorge Cubo
AU - Luiz Carlos Weinschütz
AU - Alexander Wilhelm Armin Kellner
AU - Juliana Manso Sayão
PY - 2026
DA - 2026/09/02
JO - Paleobiology
DO - 10.1017/pab.2026.10111
UR - https://hal.science/hal-05753329v1
AB - Studies on paleophysiology and thermoregulation are central topics in fossil vertebrate paleobiology because they allow inferences about extinct organismal function beyond anatomical description. Pterosaur thermophysiology remains actively debated. Evidence such as relatively rapid growth and elevated metabolic rate estimates has been used to argue for endothermic-like physiologies consistent with the energetic demands of powered flight, whereas reproductive traits, including burial incubation and precocial development, have led some authors to propose ectothermic strategies more akin to those of extant non-avian diapsids. Here, we provide quantitative estimates of resting metabolic rate (RMR) for the tapejarid pterosaur Caiuajara dobruskii using phylogenetic eigenvector maps and osteocyte lacunar density as proxy. Analysis of six histological sections from three appendicular elements (femur, tibia, humerus) at different ontogenetic stages (adult and juvenile) yielded mass-independent RMR estimates of 0.24–0.76 ml O 2 h −1 g −0.86 , substantially higher than those of lepidosaurs but lower than typical mammalian and avian values. The retrodicted mass-independent maximum metabolic rate (MMR) of 5.68 ml O 2 h −1 g −0.87 falls between values for highly active reptiles and birds, suggesting sufficient aerobic capacity to sustain powered flight without fully matching the maximal performance of small endotherms. Together, these results suggest active-flighted pterosaurs fall among a metabolically intermediate continuum, limiting straightforward actualistic comparisons for inferring their thermoregulatory strategy.
SN - 0094-8373
ER -