Growth and miniaturization among alvarezsauroid dinosaurs

Qin, Zichuan; Zhao, Qi; Choiniere, Jonah N.; Clark, James M.; Benton, Michael J.; Xu, Xing

doi:10.1016/j.cub.2021.06.013

Cited by 14 publications

(8 citation statements)

References 55 publications

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“…For example, we find that gigantism in allosauroids evolved through a range of growth strategies, not just prolongation ( 30 ) or acceleration ( 5 ). We find support for some previous evolutionary hypotheses, including truncation of rapid growth characterizing the close relatives of birds ( 2 , 21 ), and exceptionally high variability in alvarezsauroid growth rates ( 35 ). Our results generally align with clade-specific morphological studies of heterochrony in several theropod clades, including peramorphosis in carcharodontosaurids with prolonged, slow development ( 36 ) and paedomorphosis in paravians with truncated, rapid development ( 37 ).…”

supporting

confidence: 87%

Developmental strategies underlying gigantism and miniaturization in non-avialan theropod dinosaurs

D’Emic

O’Connor

Sombathy

et al. 2023

Science

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In amniotes, the predominant developmental strategy underlying body size evolution is thought to be adjustments to the rate of growth rather than its duration. However, most theoretical and experimental studies supporting this axiom focus on pairwise comparisons and/or lack an explicit phylogenetic framework. We present the first large-scale phylogenetic comparative analysis examining developmental strategies underlying the evolution of body size, focusing on non-avialan theropod dinosaurs. We reconstruct ancestral states of growth rate and body mass in a taxonomically rich dataset, finding that contrary to expectations, changes in the rate and duration of growth played nearly equal roles in the evolution of the vast body size disparity present in non-avialan theropods—and perhaps that of amniotes in general.

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supporting

confidence: 87%

Developmental strategies underlying gigantism and miniaturization in non-avialan theropod dinosaurs

D’Emic

O’Connor

Sombathy

et al. 2023

Science

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“…Dinosaurs of the group Alvarezsauroidea, have been suggested to eat termites. 57 Termites, especially the earlier representatives, likewise lived in wood; hence, these dinosaurs also have encountered the holometabolan larvae and most likely eaten them as well.…”

Section: Resultsmentioning

confidence: 99%

Fossils in Myanmar amber demonstrate the diversity of anti-predator strategies of Cretaceous holometabolan insect larvae

Haug,

Haug

et al. 2024

iScience

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“…Alvarezsauria is a highly specialized group of non-avian theropod dinosaurs with worldwide distribution (Bonaparte 1991;Altangerel et al, 1993;Hutchinson and Chiappe, 1998;Naish and Dyke, 2004;Choiniere et al, 2010;Qin et al, 2019;Qin et al, 2021). They have a lot of unique features including the extremely reduced forelimbs and digits, and also resemble birds in many aspects including cranial kinesis, keeled sternums, and backward pointed pubis.…”

Section: Discussionmentioning

confidence: 99%

“…They have a lot of unique features including the extremely reduced forelimbs and digits, and also resemble birds in many aspects including cranial kinesis, keeled sternums, and backward pointed pubis. During their evolution, Alvarezsaurian dinosaurs suffered sustained miniaturization, which might be due to the transition in diet (Xu et al, 2018;Qin et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

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Intelligent Objective Osteon Segmentation Based on Deep Learning

Qin

Liu

et al. 2022

Front. Earth Sci.

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Histology is key to understand physiology, development, growth and even reproduction of extinct animals. However, the identification and interpretation of certain structures, such as osteons, medullary bone (MB), and Lines of Arrested Growth (LAGs), are not only based on personal judgments, but also require considerable labor for subsequent analysis. Due to the dearth of available specimens, only a few quantitative histological studies have been proceeded for limited dinosaur taxa, most of which focus primarily on their growth, namely, LAGs and other growth lines without much attention to other histological structures. Here we develop a deep convolutional neural network-based method for automated osteohistological segmentation. Raw images are firstly divided into sub-images and the borders are expanded to guarantee the osteon regions integrity. ResNet-50 is employed as feature extractor and atrous spatial pyramid pooling (ASPP) is used to capture multi-scale information. A dual-resolution segmentation strategy is designed to observe the primary and secondary osteon regions from the matrix background. Finally, a segmented map with different osteon regions is obtained. This deep convolutional neural network-based model is tested on a histological dataset derived from various taxa in Alvarezsauria, a highly specialized group of non-avian theropod dinosaurs. The results show that large-scale quantitative histological analysis can be achieved by neural network-based methods, and previously hidden information by traditional methods can be revealed. Phylogenetic mapping of osteon segmentation results suggests a developmental pathway towards miniaturized body sizes in the evolution of Alvarezsauria, which may resemble the transition from non-avian dinosaurs to birds.

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Growth and miniaturization among alvarezsauroid dinosaurs

Cited by 14 publications

References 55 publications

Developmental strategies underlying gigantism and miniaturization in non-avialan theropod dinosaurs

Developmental strategies underlying gigantism and miniaturization in non-avialan theropod dinosaurs

Fossils in Myanmar amber demonstrate the diversity of anti-predator strategies of Cretaceous holometabolan insect larvae

Intelligent Objective Osteon Segmentation Based on Deep Learning

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