1
|
Skawiński T, Skórzewski G, Borczyk B. Embryonic development and perinatal skeleton in a limbless, viviparous lizard, Anguis fragilis (Squamata: Anguimorpha). PeerJ 2021; 9:e11621. [PMID: 34178475 PMCID: PMC8214852 DOI: 10.7717/peerj.11621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/25/2021] [Indexed: 11/21/2022] Open
Abstract
Despite the long history of embryological studies of squamates, many groups of this huge clade have received only limited attention. One such understudied group is the anguimorphs, a clade comprising morphologically and ecologically very diverse lizards. We describe several stages of embryonic development of Anguis fragilis, a limbless, viviparous anguimorph. Interestingly, in several clutches we observe high morphological variation in characters traditionally important in classifying embryos into developmental stages. The causes of this variation remain unknown but environmental factors do not seem to be very important. Additionally, we describe the state of ossification in several perinatal specimens of A. fragilis. The cranial skeleton is relatively poorly ossified around the time of birth, with all of the bones constituting the braincase unfused. On the other hand, the vertebral column is well ossified, with the neurocentral sutures closed and the neural arches fused in all postatlantal vertebrae. Such an advanced state of ossification may be related to the greater importance of the vertebral column in locomotion in limbless species than in ones with fully-developed limbs. Numerous factors seem to affect the state of ossification at the time of hatching or birth in squamates, including phylogenetic position, mode of reproduction and, potentially, limblessness. However, data from a greater number of species are needed to reach firmer conclusions about the relative importance of these variables in certain clades.
Collapse
Affiliation(s)
- Tomasz Skawiński
- Department of Evolutionary Biology and Conservation of Vertebrates, University of Wroclaw, Wrocław, Poland
| | | | - Bartosz Borczyk
- Department of Evolutionary Biology and Conservation of Vertebrates, University of Wroclaw, Wrocław, Poland
| |
Collapse
|
2
|
Dupoué A, Sorlin M, Richard M, Le Galliard JF, Lourdais O, Clobert J, Aubret F. Mother-offspring conflict for water and its mitigation in the oviparous form of the reproductively bimodal lizard, Zootoca vivipara. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AbstractParent-offspring conflicts are widespread given that resources are often limited. Recent evidence has shown that availability of water can trigger such conflict during pregnancy in viviparous squamate species (lizards and snakes) and thus questions the role of water in the evolution of reproductive modes. Here, we examined the impact of water restriction during gravidity in the oviparous form of the bimodal common lizard (Zootoca vivipara), using a protocol previously used on the viviparous form. Females were captured in early gravidity from six populations along a 600 m altitudinal gradient to investigate whether environmental conditions (altitude, water access and temperature) exacerbate responses to water restriction. Females were significantly dehydrated after water restriction, irrespective of their reproductive status (gravid vs. non-reproductive), relative reproductive effort (relative clutch mass), and treatment timing (embryonic development stage). Female dehydration, together with reproductive performance, varied with altitude, probably due to long term acclimation or local adaptation. This moderate water-based intergenerational conflict in gravid females contrasts sharply with previous findings for the viviparous form, with implications to the evolutionary reversion from viviparity to oviparity. It is likely that oviparity constitutes a water-saving reproductive mode which might help mitigate intensive temperature-driven population extinctions at low altitudes.
Collapse
Affiliation(s)
- Andréaz Dupoué
- Station d’Ecologie Théorique et Expérimentale de Moulis, CNRS, UMR 5321, Saint Girons, France
- School of Biological Sciences, Monash University, Clayton campus, VIC, Melbourne, Australia
| | - Mahaut Sorlin
- Station d’Ecologie Théorique et Expérimentale de Moulis, CNRS, UMR 5321, Saint Girons, France
| | - Murielle Richard
- Station d’Ecologie Théorique et Expérimentale de Moulis, CNRS, UMR 5321, Saint Girons, France
| | - Jean François Le Galliard
- iEES Paris, Sorbonne Université, CNRS, UMR 7618, Tours 44–45, Paris, France
- Ecole normale supérieure, Département de biologie, PSL Research University, CNRS, UMS 3194, Centre de recherche en écologie expérimentale et prédictive (CEREEP-Ecotron IleDeFrance), Saint-Pierre-lès-Nemours, France
| | - Olivier Lourdais
- Centre d’Etudes Biologiques de Chizé, La Rochelle Université, CNRS, UMR, Beauvoir sur Niort, France
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Jean Clobert
- Station d’Ecologie Théorique et Expérimentale de Moulis, CNRS, UMR 5321, Saint Girons, France
| | - Fabien Aubret
- Station d’Ecologie Théorique et Expérimentale de Moulis, CNRS, UMR 5321, Saint Girons, France
- School of Molecular and Life Sciences, Curtin University, Bentley, WA, Australia
| |
Collapse
|
3
|
Olsson M, Loeb L, Lindsay W, Wapstra E, Fitzpatrick L, Shine R. Extreme plasticity in reproductive biology of an oviparous lizard. Ecol Evol 2018; 8:6384-6389. [PMID: 30038742 PMCID: PMC6053574 DOI: 10.1002/ece3.4247] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 12/04/2022] Open
Abstract
Most oviparous squamate reptiles lay their eggs when embryos have completed less than one-third of development, with the remaining two-thirds spent in an external nest. Even when females facultatively retain eggs in dry or cold conditions, such retention generally causes only a minor (<10%) decrease in subsequent incubation periods. In contrast, we found that female sand lizards (Lacerta agilis) from an experimentally founded field population (established ca. 20 years ago on the southwest coast of Sweden) exhibited wide variation in incubation periods even when the eggs were kept at standard (25°C) conditions. Females that retained eggs in utero for longer based on the delay between capture and oviposition produced eggs that hatched sooner. In the extreme case, eggs hatched after only 55% of the "normal" incubation period. Although the proximate mechanisms underlying this flexibility remain unclear, our results from this first full field season at the new study site show that females within a single cold-climate population of lizards can span a substantial proportion of the continuum from "normal" oviparity to viviparity.
Collapse
Affiliation(s)
- Mats Olsson
- Division of Animal EcologyDepartment of ZoologyUniversity of GothenburgGothenburgSweden
- School of Biological SciencesUniversity of WollongongWollongongNSWAustralia
| | - Lisa Loeb
- Division of Animal EcologyDepartment of ZoologyUniversity of GothenburgGothenburgSweden
| | - Willow Lindsay
- Division of Animal EcologyDepartment of ZoologyUniversity of GothenburgGothenburgSweden
| | - Erik Wapstra
- School of Biological SciencesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Luisa Fitzpatrick
- School of Biological SciencesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Richard Shine
- School of Life and Environmental SciencesUniversity of SydneySydneyNSWAustralia
| |
Collapse
|