1
|
Han F, Yu Y, Zhang S, Zeng R, Wang X, Cai H, Wu T, Wen Y, Cai S, Li C, Wu R, Zhao Q, Xu X. Exceptional Early Jurassic fossils with leathery eggs shed light on dinosaur reproductive biology. Natl Sci Rev 2024; 11:nwad258. [PMID: 38707200 PMCID: PMC11067957 DOI: 10.1093/nsr/nwad258] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 05/07/2024] Open
Abstract
Our understanding of pre-Cretaceous dinosaur reproduction is hindered by a scarcity of evidence within fossil records. Here we report three adult skeletons and five clutches of embryo-containing eggs of a new sauropodomorph from the Lower Jurassic of southwestern China, displaying several significant reproductive features that are either unknown or unlike other early-diverging sauropodomorphs, such as relatively large eggs with a relatively thick calcareous shell formed by prominent mammillary cones, synchronous hatching and a transitional prehatching posture between the crocodilians and living birds. Most significantly, these Early Jurassic fossils provide strong evidence for the earliest known leathery eggs. Our comprehensive quantitative analyses demonstrate that the first dinosaur eggs were probably leathery, elliptical and relatively small, but with relatively long eggshell units, and that along the line to living birds, the most significant change in reptilian egg morphology occurred early in theropod evolution rather than near the origin of Aves.
Collapse
Affiliation(s)
- Fenglu Han
- School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Yilun Yu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Shukang Zhang
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
| | - Rong Zeng
- Guizhou Provincial Museum, Guiyang 550081, China
| | - Xinjin Wang
- Guizhou Provincial Institute of Cultural Relics and Archaeology, Guiyang 550001, China
| | - Huiyang Cai
- Guizhou Provincial Museum, Guiyang 550081, China
| | | | - Yingfeng Wen
- Pingba Institute of Cultural Relics Administration, Anshun 550820, China
| | - Sifu Cai
- Guizhou Provincial Museum, Guiyang 550081, China
| | - Chun Li
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
| | - Rui Wu
- School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Qi Zhao
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
| | - Xing Xu
- Centre for Vertebrate Evolutionary Biology, Yunnan University, Kunming 650091, China
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
| |
Collapse
|
2
|
Chinsamy A. Palaeoecological deductions from osteohistology. Biol Lett 2023; 19:20230245. [PMID: 37607578 PMCID: PMC10444344 DOI: 10.1098/rsbl.2023.0245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 07/31/2023] [Indexed: 08/24/2023] Open
Abstract
Palaeoecological deductions are vital for understanding the evolution and diversification of species within prehistoric environments. This review highlights the multitude of ways in which the microanatomy and microscopic structure of bones enables palaeoecological deductions. The occurrence of growth marks in bones is discussed, and their usefulness in deducing the ontogenetic status and age of individuals is considered, as well as how such marks in bones permit the assessment of the growth dynamics of individuals and species. Here osteohistology is shown to provide insight into the structure of past populations, as well as ecological relationships between individuals. In addition, the response of bones to trauma, disease and moulting is considered. Finally, I explore how osteohistology can give insight into ecomorphological adaptations, such as filter feeding, probe feeding and saltatorial locomotion. Methodological advances in three-dimensional microtomography and synchrotron scanning bodes well for future studies in osteohistology and despite some compromises in terms of tissue identity, circumvents the crucial issue of destructive analyses.
Collapse
Affiliation(s)
- Anusuya Chinsamy
- Department of Biological Sciences, University of Cape Town, John Day Building, University Avenue, Rondebosch 7700, South Africa
| |
Collapse
|
3
|
Reiner A. Could theropod dinosaurs have evolved to a human level of intelligence? J Comp Neurol 2023; 531:975-1006. [PMID: 37029483 PMCID: PMC10106414 DOI: 10.1002/cne.25458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 01/05/2023] [Accepted: 01/11/2023] [Indexed: 04/09/2023]
Abstract
Noting that some theropod dinosaurs had large brains, large grasping hands, and likely binocular vision, paleontologist Dale Russell suggested that a branch of these dinosaurs might have evolved to a human intelligence level, had dinosaurs not become extinct. I offer reasons why the likely pallial organization in dinosaurs would have made this improbable, based on four assumptions. First, it is assumed that achieving human intelligence requires evolving an equivalent of the about 200 functionally specialized cortical areas characteristic of humans. Second, it is assumed that dinosaurs had an avian nuclear type of pallial organization, in contrast to the mammalian cortical organization. Third, it is assumed that the interactions between the different neuron types making up an information processing unit within pallium are critical to its role in analyzing information. Finally, it is assumed that increasing axonal length between the neuron sets carrying out this operation impairs its efficacy. Based on these assumptions, I present two main reasons why dinosaur pallium might have been unable to add the equivalent of 200 efficiently functioning cortical areas. First, a nuclear pattern of pallial organization would require increasing distances between the neuron groups corresponding to the separate layers of any given mammalian cortical area, as more sets of nuclei equivalent to a cortical area are interposed between the existing sets, increasing axon length and thereby impairing processing efficiency. Second, because of its nuclear organization, dinosaur pallium could not reduce axon length by folding to bring adjacent areas closer together, as occurs in cerebral cortex.
Collapse
Affiliation(s)
- Anton Reiner
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| |
Collapse
|
4
|
Doody JS, Burghardt G, Dinets V. The Evolution of Sociality and the Polyvagal Theory. Biol Psychol 2023; 180:108569. [PMID: 37094735 DOI: 10.1016/j.biopsycho.2023.108569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 04/15/2023] [Accepted: 04/21/2023] [Indexed: 04/26/2023]
Abstract
The polyvagal theory (PT), offered by Porges (2021), proposes that the autonomic nervous system (ANS) was repurposed in mammals, via a "second vagal nerve", to suppress defensive strategies and support the expression of sociality. Three critical assumptions of this theory are that (1) the transition of the ANS was associated with the evolution of 'social' mammals from 'asocial' reptiles; (2) the transition enabled mammals, unlike their reptilian ancestors, to derive a biological benefit from social interactions; and (3) the transition forces a less parsimonious explanation (convergence) for the evolution of social behavior in birds and mammals, since birds evolved from a reptilian lineage. Two recently published reviews, however, provided compelling evidence that the social-asocial dichotomy is overly simplistic, neglects the diversity of vertebrate social systems, impedes our understanding of the evolution of social behavior, and perpetuates the erroneous belief that one group-non-avian reptiles-is incapable of complex social behavior. In the worst case, if PT depends upon a transition from 'asocial reptiles' to 'social mammals,' then the ability of PT to explain the evolution of the mammalian ANS is highly questionable. A great number of social behaviors occur in both reptiles and mammals. In the best case, PT has misused the terms 'social' and 'asocial'. Even here, however, the theory would still need to identify a particular suite of behaviors found in mammals and not reptiles that could be associated with, or explain, the transition of the ANS, and then replace the 'asocial' and 'social' labels with more specific descriptors.
Collapse
Affiliation(s)
- J Sean Doody
- Department of Integrative Biology, University of South Florida - St. Petersburg Campus, 140 7(th) Ave. South, St. Petersburg, Florida 33701, USA
| | - Gordon Burghardt
- Department of Psychology, University of Tennessee, 1404 Circle Drive, Knoxville, TN 37996; Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996
| | - Vladimir Dinets
- Department of Psychology, University of Tennessee, 1404 Circle Drive, Knoxville, TN 37996
| |
Collapse
|
5
|
Devereux HL, Turner MS. Environmental Path-Entropy and Collective Motion. PHYSICAL REVIEW LETTERS 2023; 130:168201. [PMID: 37154632 DOI: 10.1103/physrevlett.130.168201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/18/2023] [Accepted: 03/28/2023] [Indexed: 05/10/2023]
Abstract
Inspired by the swarming or flocking of animal systems we study groups of agents moving in unbounded 2D space. Individual trajectories derive from a "bottom-up" principle: individuals reorient to maximize their future path entropy over environmental states. This can be seen as a proxy for keeping options open, a principle that may confer evolutionary fitness in an uncertain world. We find an ordered (coaligned) state naturally emerges, as well as disordered states or rotating clusters; similar phenotypes are observed in birds, insects, and fish, respectively. The ordered state exhibits an order-disorder transition under two forms of noise: (i) standard additive orientational noise, applied to the postdecision orientations and (ii) "cognitive" noise, overlaid onto each individual's model of the future paths of other agents. Unusually, the order increases at low noise, before later decreasing through the order-disorder transition as the noise increases further.
Collapse
Affiliation(s)
- Harvey L Devereux
- Department of Mathematics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Matthew S Turner
- Department of Physics and Centre for Complexity Science, University of Warwick, Coventry CV4 7AL, United Kingdom and Department of Chemical Engineering, Kyoto University, Kyoto 615-8510, Japan
| |
Collapse
|
6
|
At the root of the mammalian mind: The sensory organs, brain and behavior of pre-mammalian synapsids. PROGRESS IN BRAIN RESEARCH 2023; 275:25-72. [PMID: 36841570 DOI: 10.1016/bs.pbr.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
All modern mammals are descendants of the paraphyletic non-mammaliaform Synapsida, colloquially referred to as the "mammal-like reptiles." It has long been assumed that these mammalian ancestors were essentially reptile-like in their morphology, biology, and behavior, i.e., they had a small brain, displayed simple behavior, and their sensory organs were unrefined compared to those of modern mammals. Recent works have, however, revealed that neurological, sensory, and behavioral traits previously considered typically mammalian, such as whiskers, enhanced olfaction, nocturnality, parental care, and complex social interactions evolved before the origin of Mammaliaformes, among the early-diverging "mammal-like reptiles." In contrast, an enlarged brain did not evolve immediately after the origin of mammaliaforms. As such, in terms of paleoneurology, the last "mammal-like reptiles" were not significantly different from the earliest mammaliaforms. The abundant data and literature published in the last 10 years no longer supports the "three pulses" scenario of synapsid brain evolution proposed by Rowe and colleagues in 2011, but supports the new "outside-in" model of Rodrigues and colleagues proposed in 2018, instead. As Mesozoic reptiles were becoming the dominant taxa within terrestrial ecosystems, synapsids gradually adapted to smaller body sizes and nocturnality. This resulted in a sensory revolution in synapsids as olfaction, audition, and somatosensation compensated for the loss of visual cues. This altered sensory input is aligned with changes in the brain, the most significant of which was an increase in relative brain size.
Collapse
|
7
|
Triassic sauropodomorph eggshell might not be soft. Nature 2022; 610:E8-E10. [PMID: 36261569 DOI: 10.1038/s41586-022-05151-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 07/27/2022] [Indexed: 11/08/2022]
|
8
|
Schade M, Knötschke N, Hörnig MK, Paetzel C, Stumpf S. Neurovascular anatomy of dwarf dinosaur implies precociality in sauropods. eLife 2022; 11:82190. [PMID: 36537069 PMCID: PMC9767461 DOI: 10.7554/elife.82190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/11/2022] [Indexed: 12/24/2022] Open
Abstract
Macronaria, a group of mostly colossal sauropod dinosaurs, comprised the largest terrestrial vertebrates of Earth's history. However, some of the smallest sauropods belong to this group as well. The Late Jurassic macronarian island dwarf Europasaurus holgeri is one of the most peculiar and best-studied sauropods worldwide. So far, the braincase material of this taxon from Germany pended greater attention. With the aid of micro-computed tomography (microCT), we report on the neuroanatomy of the nearly complete braincase of an adult individual, as well as the inner ears (endosseous labyrinths) of one other adult and several juveniles (the latter also containing novel vascular cavities). The presence of large and morphologically adult inner ears in juvenile material suggests precociality. Our findings add to the diversity of neurovascular anatomy in sauropod braincases and buttress the perception of sauropods as fast-growing and autonomous giants with manifold facets of reproductive and social behaviour. This suggests that - apart from sheer size - little separated Europasaurus from its large-bodied relatives.
Collapse
Affiliation(s)
- Marco Schade
- University of Greifswald, Institute of Geography and Geology, Palaeontology and HistoricalGreifswaldGermany,University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary BiologyGreifswaldGermany
| | | | - Marie K Hörnig
- University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary BiologyGreifswaldGermany
| | - Carina Paetzel
- University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary BiologyGreifswaldGermany
| | | |
Collapse
|