1
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Francis C, Hale A, Berken J, Joanen T, Merchant M. Morphological and Ontogenetic Skin Color Changes in the American Alligator ( Alligator mississippiensis). Animals (Basel) 2023; 13:3440. [PMID: 38003058 PMCID: PMC10668839 DOI: 10.3390/ani13223440] [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: 09/06/2023] [Revised: 10/15/2023] [Accepted: 10/16/2023] [Indexed: 11/26/2023] Open
Abstract
To assess skin color change in alligators, we maintained animals in differently lighted environments and also measured skin colors in an ontogenetic series of wild animals. Juvenile alligators maintained in black enclosures exhibited a gradual lightening of skin color when shifted to white enclosures, and these observed changes were reversible. A histological examination of the skins of alligators maintained in dark tanks showed that the dermis exhibited a dense layer of pigmented cells, while samples from the same animals in light environments exhibited a more diffuse pigmented layer. As alligators grow, they exhibit an ontogenetic loss of stripes that may aid in crypsis and predation. Hatchlings have intense black and yellow vertical stripes that darken with age; adults are a more homogenous black/gray color. Since alligators live in temperate climates and adults have lower surface area/volume ratios, which can be detrimental for the absorption of radiant energy, the darker color of larger animals may also aid in thermoregulation. Alligators at the northern end of their range, with colder climates, exhibited darker skin tones, and the ontogenetic extinction of stripes occurred at a more accelerated rate compared to animals in southern, warmer regions, supporting the idea that latitude-dependent ontogenetic color shift has a role in thermoregulation.
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Affiliation(s)
- Cadre Francis
- Department of Chemistry, McNeese State University, Lake Charles, LA 70605, USA
| | - Amber Hale
- Department of Biology, McNeese State University, Lake Charles, LA 70605, USA;
| | - Jennifer Berken
- Department of Mathematical Sciences, McNeese State University, Lake Charles, LA 70605, USA;
| | - Ted Joanen
- Louisiana Department of Wildlife and Fisheries, Grand Chenier, LA 70808, USA;
| | - Mark Merchant
- Department of Chemistry, McNeese State University, Lake Charles, LA 70605, USA
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2
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Thévenet J, Papet L, Coureaud G, Boyer N, Levréro F, Grimault N, Mathevon N. Crocodile perception of distress in hominid baby cries. Proc Biol Sci 2023; 290:20230201. [PMID: 37554035 PMCID: PMC10410202 DOI: 10.1098/rspb.2023.0201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 07/07/2023] [Indexed: 08/10/2023] Open
Abstract
It is generally argued that distress vocalizations, a common modality for alerting conspecifics across a wide range of terrestrial vertebrates, share acoustic features that allow heterospecific communication. Yet studies suggest that the acoustic traits used to decode distress may vary between species, leading to decoding errors. Here we found through playback experiments that Nile crocodiles are attracted to infant hominid cries (bonobo, chimpanzee and human), and that the intensity of crocodile response depends critically on a set of specific acoustic features (mainly deterministic chaos, harmonicity and spectral prominences). Our results suggest that crocodiles are sensitive to the degree of distress encoded in the vocalizations of phylogenetically very distant vertebrates. A comparison of these results with those obtained with human subjects confronted with the same stimuli further indicates that crocodiles and humans use different acoustic criteria to assess the distress encoded in infant cries. Interestingly, the acoustic features driving crocodile reaction are likely to be more reliable markers of distress than those used by humans. These results highlight that the acoustic features encoding information in vertebrate sound signals are not necessarily identical across species.
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Affiliation(s)
- Julie Thévenet
- ENES Bioacoustics Research Laboratory, CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, Rhône-Alpes, France
- Equipe Cognition Auditive et Psychoacoustique, CRNL, CNRS, Inserm, University Lyon 1, Villeurbanne 69622, France
| | - Léo Papet
- ENES Bioacoustics Research Laboratory, CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, Rhône-Alpes, France
- Equipe Cognition Auditive et Psychoacoustique, CRNL, CNRS, Inserm, University Lyon 1, Villeurbanne 69622, France
| | - Gérard Coureaud
- ENES Bioacoustics Research Laboratory, CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, Rhône-Alpes, France
| | - Nicolas Boyer
- ENES Bioacoustics Research Laboratory, CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, Rhône-Alpes, France
| | - Florence Levréro
- ENES Bioacoustics Research Laboratory, CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, Rhône-Alpes, France
| | - Nicolas Grimault
- Equipe Cognition Auditive et Psychoacoustique, CRNL, CNRS, Inserm, University Lyon 1, Villeurbanne 69622, France
| | - Nicolas Mathevon
- ENES Bioacoustics Research Laboratory, CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, Rhône-Alpes, France
- Institut universitaire de France, Paris, Île-de-France, France
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3
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Hechenleitner EM, Fernandez Blanco MV, Núñez-Campero SR, Fiorelli LE, Bona P. Unexpected morphological variability in the eggshells of the South American caimans Caiman latirostris and Caiman yacare. Sci Rep 2023; 13:4894. [PMID: 36966165 PMCID: PMC10039913 DOI: 10.1038/s41598-023-31837-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/17/2023] [Indexed: 03/27/2023] Open
Abstract
Eggshell morphology is a valuable indicator of the local conditions within the nests of modern crocodilians and birds. In contrast to these latter, the anatomical structure of the eggshells of most crocodilian species is practically unknown. Here, we provide the first characterization of crocodilian eggshells, using x-ray micro-CT scans. We studied eggshells of Caiman latirostris and Caiman yacare from various developmental stages that coincide with the beginning of embryonic ossification. The new 3D renderings revealed complex ornamentation, unique among crocodilians, and amphora-shaped pore canals, some of which converge in single pore openings. We also documented a high density of pore canals with a gas diffusion capacity 45 times higher than the average predicted for modern avian eggshells. The external ornamentation and the thickness of the compact layer of the eggshells (i.e. excluding ornamentation) showed ontogenetic and interspecific differences that could be related to nesting materials and nesting areas selected by each species. The shell features described here evidence a greater structural complexity than previously recognized in phylogenetically close, sympatric crocodilian species. Further comprehensive morphological analyses on other modern and fossil crocodilian eggshells using micro-CT technology will shed new light on the evolution of reproductive strategies in this intriguing archosaur clade.
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Affiliation(s)
- E Martín Hechenleitner
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, CABA, Argentina.
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR), Provincia de La Rioja, UNLaR, SEGEMAR, UNCa, CONICET, Entre Ríos y Mendoza S/N, 5301, Anillaco, La Rioja, Argentina.
- Instituto de Biología de La Conservación y Paleobiología (IBICOPA) DACEFyN-UNLaR, Av. Gob. Vernet y Apóstol Felipe, 5300, La Rioja, Argentina.
| | - María V Fernandez Blanco
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, CABA, Argentina.
- División Paleontología Vertebrados, Anexo II Laboratorios del Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Calles 122 y 60, B1900FWA, La Plata, Buenos Aires, Argentina.
| | - Segundo R Núñez-Campero
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, CABA, Argentina
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR), Provincia de La Rioja, UNLaR, SEGEMAR, UNCa, CONICET, Entre Ríos y Mendoza S/N, 5301, Anillaco, La Rioja, Argentina
- Instituto de Biología de La Conservación y Paleobiología (IBICOPA) DACEFyN-UNLaR, Av. Gob. Vernet y Apóstol Felipe, 5300, La Rioja, Argentina
| | - Lucas E Fiorelli
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, CABA, Argentina
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR), Provincia de La Rioja, UNLaR, SEGEMAR, UNCa, CONICET, Entre Ríos y Mendoza S/N, 5301, Anillaco, La Rioja, Argentina
| | - Paula Bona
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, CABA, Argentina
- División Paleontología Vertebrados, Anexo II Laboratorios del Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Calles 122 y 60, B1900FWA, La Plata, Buenos Aires, Argentina
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4
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Rogerson G, Bock S, Loera Y, Parrott B, Mulley JF. Incubation temperature alters stripe formation and head colouration in American alligator hatchlings and is unaffected by estradiol-induced sex reversal. J Exp Biol 2023; 226:jeb245219. [PMID: 36861779 PMCID: PMC10112970 DOI: 10.1242/jeb.245219] [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: 10/20/2022] [Accepted: 02/24/2023] [Indexed: 03/03/2023]
Abstract
Considerations of the impact climate change has on reptiles are typically focused on habitat change or loss, range shifts and skewed sex ratios in species with temperature-dependent sex determination. Here, we show that incubation temperature alters stripe number and head colouration of hatchling American alligators (Alligator mississippiensis). Animals incubated at higher temperatures (33.5°C) had, on average, one more stripe than those at lower temperatures (29.5°C), and also had significantly lighter heads. These patterns were not affected by estradiol-induced sex reversal, suggesting independence from hatchling sex. Therefore, increases in nest temperatures as a result of climate change have the potential to alter pigmentation patterning, which may have implications for offspring fitness.
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Affiliation(s)
- Grace Rogerson
- School of Natural Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| | - Samantha Bock
- Odum School of Ecology, University of Georgia,Athens, GA 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA
| | - Yeraldi Loera
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Benjamin Parrott
- Odum School of Ecology, University of Georgia,Athens, GA 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA
| | - John F. Mulley
- School of Natural Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
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5
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Lawson AJ, Jodice PGR, Rainwater TR, Dunham KD, Hart M, Butfiloski JW, Wilkinson PM, McFadden KW, Moore CT. Hidden in plain sight: Integrated population models to resolve partially observable latent population structure. Ecosphere 2022. [DOI: 10.1002/ecs2.4321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Abigail J. Lawson
- Department of Forestry and Environmental Conservation Clemson University Clemson South Carolina USA
| | - Patrick G. R. Jodice
- U.S. Geological Survey, South Carolina Cooperative Fish and Wildlife Research Unit Clemson University Clemson South Carolina USA
| | - Thomas R. Rainwater
- Department of Forestry and Environmental Conservation Clemson University Clemson South Carolina USA
- Baruch Institute of Coastal Ecology and Forest Science Clemson University Georgetown South Carolina USA
- Tom Yawkey Wildlife Center Georgetown South Carolina USA
| | - Kylee D. Dunham
- U.S. Geological Survey, Eastern Ecological Science Center Laurel Maryland USA
| | - Morgan Hart
- South Carolina Department of Natural Resources Columbia South Carolina USA
| | | | | | - K. W. McFadden
- U.S. Geological Survey, South Carolina Cooperative Fish and Wildlife Research Unit Clemson University Clemson South Carolina USA
| | - Clinton T. Moore
- U.S. Geological Survey, Georgia Cooperative Fish and Wildlife Research Unit, Warnell School of Forestry and Natural Resources University of Georgia Athens Georgia USA
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6
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Isberg SR. How many fathers? Study design implications when inferring multiple paternity in crocodilians. Ecol Evol 2022; 12:e9379. [PMID: 36225824 PMCID: PMC9534745 DOI: 10.1002/ece3.9379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/24/2022] [Accepted: 09/16/2022] [Indexed: 11/10/2022] Open
Abstract
Up to 10 males were reported to sire clutches of crocodilian eggs but review of the underlying study designs raised questions of potential upward bias of inferred sire numbers. To test this premise, different scenarios were explored using a published dataset of 16 known single-sire saltwater crocodile pairs and their offspring which were originally confirmed using a 11 loci microsatellite panel in CERVUS. Varying the number of microsatellites, omitting one or both parental genotypes and using different parentage analysis techniques revealed that total allele number, rather than number of loci, determined inferred sire accuracy in two opposing ways. Using the single-locus minimum method and GERUD, which both require prior knowledge of family groupings (i.e., nests), fewer alleles (and loci) accurately inferred only one father. In contrast, CERVUS and COLONY required all 11 loci (65 alleles) and both parental genotypes to (a) assign correct family groups and (b) infer the correct sire number, except in one family where two sires were equally assigned based on their number of homozygous loci. When less genotype information was provided, CERVUS and COLONY inferred up to six and seven sires, respectively. Given this data is from confirmed single-sire matings, and yet up to seven sires could be inferred, the significance of inappropriate study design is clearly demonstrated. Consideration should be carefully given to genotype data, particularly those collected specifically for population diversity studies, which are also used to infer multiple paternity because the underlying data collection assumptions are not equivalent between the two outcomes.
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Affiliation(s)
- Sally R. Isberg
- Centre for Crocodile ResearchNoonamahNorthern TerritoryAustralia
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7
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Morris ZS, Vliet KA, Abzhanov A, Pierce SE. Developmental origins of the crocodylian skull table and platyrostral face. Anat Rec (Hoboken) 2021; 305:2838-2853. [PMID: 34694063 DOI: 10.1002/ar.24802] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/13/2021] [Indexed: 11/10/2022]
Abstract
The dorsoventrally flattened skull typifies extant Crocodylia perhaps more than any other anatomical feature and is generally considered an adaptation for semi-aquatic feeding. Although the evolutionary origins of caniofacial flattening have been extensively studied, the developmental origins have yet to be explored. To understand how the skull table and platyrostral snout develop, we quantified embryonic development and post-hatching growth (ontogeny) of the crocodylian skull in lateral view using geometric morphometrics. Our dataset (n = 103) includes all but one extant genus and all of the major ecomorphs, including the extremely slender-snouted Gavialis and Tomistoma. Our analysis reveals that the embryonic development of the flattened skull is remarkably similar across ecomorphs, including the presence of a conserved initial embryonic skull shape, similar to prior analysis of dorsal snout shape. Although differences during posthatching ontogeny are recovered among ecomorphs, embryonic patterns are not distinct, revealing an important shift in developmental rate near hatching. In particular, the flattened skull table is achieved by the end of embryonic development with no changes after hatching. Further, the rotation of skull roof and facial bones during development is critical for the stereotypical flatness of the crocodylian skull. Our results suggest selection on hatchling performance and constraints on embryonic skull shape may have been important in this pattern of developmental conservation. The appearance of aspects of cranial flatness among Jurassic stem crocodylians suggests key aspects of these cranial developmental patterns may have been conserved for over 200 million years.
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Affiliation(s)
- Zachary S Morris
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Kent A Vliet
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Arhat Abzhanov
- Department of Life Sciences, Imperial College London, Berkshire, UK.,Natural History Museum, Cromwell Road, London, UK
| | - Stephanie E Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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8
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Reber SA, Oh J, Janisch J, Stevenson C, Foggett S, Wilkinson A. Early life differences in behavioral predispositions in two Alligatoridae species. Anim Cogn 2021; 24:753-764. [PMID: 33454828 PMCID: PMC8238711 DOI: 10.1007/s10071-020-01461-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/13/2020] [Accepted: 12/16/2020] [Indexed: 11/25/2022]
Abstract
Behavioral predispositions are innate tendencies of animals to behave in a given way without the input of learning. They increase survival chances and, due to environmental and ecological challenges, may vary substantially even between closely related taxa. These differences are likely to be especially pronounced in long-lived species like crocodilians. This order is particularly relevant for comparative cognition due to its phylogenetic proximity to birds. Here we compared early life behavioral predispositions in two Alligatoridae species. We exposed American alligator and spectacled caiman hatchlings to three different novel situations: a novel object, a novel environment that was open and a novel environment with a shelter. This was then repeated a week later. During exposure to the novel environments, alligators moved around more and explored a larger range of the arena than the caimans. When exposed to the novel object, the alligators reduced the mean distance to the novel object in the second phase, while the caimans further increased it, indicating diametrically opposite ontogenetic development in behavioral predispositions. Although all crocodilian hatchlings face comparable challenges, e.g., high predation pressure, the effectiveness of parental protection might explain the observed pattern. American alligators are apex predators capable of protecting their offspring against most dangers, whereas adult spectacled caimans are frequently predated themselves. Their distancing behavior might be related to increased predator avoidance and also explain the success of invasive spectacled caimans in the natural habitats of other crocodilians.
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Affiliation(s)
- Stephan A Reber
- School of Life Sciences, University of Lincoln, Lincoln, UK.
- Department of Cognitive Biology, University of Vienna, Vienna, Austria.
- Lund University Cognitive Science, Lund University, Lund, Sweden.
| | - Jinook Oh
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Judith Janisch
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
- Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | | | | | - Anna Wilkinson
- School of Life Sciences, University of Lincoln, Lincoln, UK.
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9
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Lemaire J, Marquis O, Bustamante P, Mangione R, Brischoux F. I got it from my mother: Inter-nest variation of mercury concentration in neonate Smooth-fronted Caiman (Paleosuchus trigonatus) suggests maternal transfer and possible phenotypical effects. ENVIRONMENTAL RESEARCH 2021; 194:110494. [PMID: 33220243 DOI: 10.1016/j.envres.2020.110494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 06/11/2023]
Abstract
The deleterious effects of mercury (Hg) contamination are well documented in humans and wildlife. Chronic exposure via diet and maternal transfer are two pathways which increase the toxicological risk for wild populations. However, few studies examined the physiological impact of Hg in crocodilians. We investigated the Hg contamination in neonate Smooth-fronted Caimans, Paleosuchus trigonatus, and the use of keratinized tissues and blood to evaluate maternal transfer. Between November 2017 and February 2020, we sampled 38 neonates from 4 distinct nests. Mercury concentration was measured in claws, scutes and total blood. Highest Hg concentrations were found in claws. Strong inter-nest variations (Hg ranging from 0.17 ± 0.02 to 0.66 ± 0.07 μg.g-1 dw) presumably reflect maternal transfer. Reduced body size in neonates characterized by elevated Hg concentrations suggests an influence of Hg during embryonic development. We emphasize the use of claws as an alternative to egg collection to investigate maternal transfer in crocodilians. Our results demonstrated the need of further investigation of the impact of Hg contamination in the first life stages of crocodilians.
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Affiliation(s)
- Jérémy Lemaire
- Centre D'Etudes Biologiques de Chizé, (CEBC) UMR 7372 CNRS-La Rochelle Université, 79360, Villiers en Bois, France; Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 Rue Olympe de Gouges, 17000, La Rochelle, France.
| | - Olivier Marquis
- Muséum National D'Histoire Naturelle, Parc Zoologique de Paris, 53 Avenue de Saint Maurice, 75012, Paris, France
| | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 Rue Olympe de Gouges, 17000, La Rochelle, France; Institut Universitaire de France (IUF), 1 Rue Descartes, 75005, Paris, France
| | - Rosanna Mangione
- Haus des Meeres Aqua Terra Zoo GmbH, Fritz-Grünbaum Platz 1, 1060, Vienna, Austria
| | - François Brischoux
- Centre D'Etudes Biologiques de Chizé, (CEBC) UMR 7372 CNRS-La Rochelle Université, 79360, Villiers en Bois, France
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10
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Dumont MV, Santucci RM, de Andrade MB, de Oliveira CEM. Paleoneurology of Baurusuchus (Crocodyliformes: Baurusuchidae), ontogenetic variation, brain size, and sensorial implications. Anat Rec (Hoboken) 2020; 305:2670-2694. [PMID: 33211405 DOI: 10.1002/ar.24567] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 09/18/2020] [Accepted: 10/18/2020] [Indexed: 12/23/2022]
Abstract
Knowledge on crocodyliform paleoneurology has significantly improved with development of computed tomography. However, studies so far have been able to reconstruct brain endocasts based only on single specimens for each taxon. Here for the first time, we reconstructed brain endocasts for multiple fossil specimens of the same crocodyliform taxon (Baurusuchus), consisting of complete skulls of two medium sized specimens, one large adult, and a late juvenile. In addition, we were able to reconstruct the inner ear anatomy of a fragmentary skull using microtomography. We present estimates of brain size using simple models, based on modern Crocodylia, able to adapt brain to endocranial cavity ratios to expected ontogenetic variation instead of using fixed ratios. We also analyzed relative brain sizes, olfactory ratios, facial sensation, alert head posture, best hearing frequencies, and hearing range. The calculated endocranial volumes showed that they can be greatly altered by taphonomic processes, altering both total and partial endocranial volumes. Reconstructed endocasts are compatible with different degrees of occupation along the endocranial cavity and some of their characteristics might be useful as phylogenetic characters. The relative brain size of Baurusuchus seems to be small in comparison to modern crocodilians. Sensorial abilities were somewhat similar to modern crocodilians and hearing ranges and best mean frequencies remarkably similar to modern taxa, whereas olfactory ratio values are a little higher. Differing from its modern relatives, Baurusuchus hypothesized alert head posture is compatible with a terrestrial habit.
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Affiliation(s)
- Marcos V Dumont
- Federal Institute of Brasília, Brasília, Brazil.,University of Brasília, Brasília, Brazil
| | | | - Marco Brandalise de Andrade
- Pontifical Catholic University of Rio Grande do Sul, PUCRS, School of Health and Life Sciences, Porto Alegre, Brazil
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11
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Viotto EV, Navarro JL, Piña CI. Growth Curves of Wild and Reintroduced Broad-Snouted Caimans (Caiman latirostris) and Their Management Implications. SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2020. [DOI: 10.2994/sajh-d-18-00077.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Evangelina V. Viotto
- Centro de Investigación Científica y de Transferencia Tecnológica a la Producción - Consejo Nacional de Investigaciones Científicas y Técnicas - Provincia de Entre Ríos-Universidad Autónoma de Entre Ríos. Dr. Materi y España. CP 3105. Diamante, Entre
| | - Joaquín L. Navarro
- Centro de Zoología Aplicada, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba. Rondeau 798, CP 5000, Córdoba, Argentina
| | - Carlos I. Piña
- Centro de Investigación Científica y de Transferencia Tecnológica a la Producción - Consejo Nacional de Investigaciones Científicas y Técnicas - Provincia de Entre Ríos-Universidad Autónoma de Entre Ríos. Dr. Materi y España. CP 3105. Diamante, Entre
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12
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González-Desales GA, Tello-Sahagún LA, Cadena-Ramírez CP, López-Luna MA, Buenrostro-Silva A, García-Grajales J, González-Ramón MC, Morales-Mavil JE, Charruau P, Sigler L, Rubio-Delgado A, Zarco-González MM, Monroy-Vilchis O. Egg predation and vertebrates associated with wild crocodilian nests in Mexico determined using camera-traps. J NAT HIST 2020. [DOI: 10.1080/00222933.2020.1829723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Giovany A. González-Desales
- Centro de Investigación en Ciencias Biológicas Aplicadas, Universidad Autónoma del Estado de México, Toluca, México
| | | | | | - Marco A. López-Luna
- Instituto de Neuroetología, Universidad Veracruzana, Xalapa Enríquez, México
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, México
| | - Alejandra Buenrostro-Silva
- Instituto de Industrias, Instituto de Recursos, Universidad del Mar-Puerto Escondido, San Pedro Mixtepec, México
| | - Jesús García-Grajales
- Instituto de Industrias, Instituto de Recursos, Universidad del Mar-Puerto Escondido, San Pedro Mixtepec, México
| | - Mariana C. González-Ramón
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, México
| | | | - Pierre Charruau
- Centro del Cambio Global y la Sustentabilidad A.C, Villahermosa, México
| | | | | | - Martha M. Zarco-González
- Centro de Investigación en Ciencias Biológicas Aplicadas, Universidad Autónoma del Estado de México, Toluca, México
| | - Octavio Monroy-Vilchis
- Centro de Investigación en Ciencias Biológicas Aplicadas, Universidad Autónoma del Estado de México, Toluca, México
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13
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DeSana A, Fargevieille A, Warner DA. Survival of lizard eggs varies with microhabitat in the presence of an invertebrate nest predator. Evol Ecol 2020. [DOI: 10.1007/s10682-020-10058-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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La Grange LJ, Mukaratirwa S. Epidemiology and hypothetical transmission cycles of Trichinella infections in the Greater Kruger National Park of South Africa: an example of host-parasite interactions in an environment with minimal human interactions. Parasite 2020; 27:13. [PMID: 32163031 PMCID: PMC7067144 DOI: 10.1051/parasite/2020010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 02/24/2020] [Indexed: 01/20/2023] Open
Abstract
Knowledge on the epidemiology, host range and transmission of Trichinella spp. infections in different ecological zones in southern Africa including areas of wildlife-human interface is limited. The majority of reports on Trichinella infections in sub-Saharan Africa were from wildlife resident in protected areas. Elucidation of the epidemiology of the infections and the prediction of hosts involved in the sylvatic cycles within specific ecological niches is critical. Of recent, there have been reports of Trichinella infections in several wildlife species within the Greater Kruger National Park (GKNP) of South Africa, which has prompted the revision and update of published hypothetical transmission cycles including the hypothetical options based previously on the biology and feeding behaviour of wildlife hosts confined to the GKNP. Using data gathered from surveillance studies and reports spanning the period 1964-2019, confirmed transmission cycles and revised hypothesized transmission cycles of three known Trichinella species (T. zimbabwensis, Trichinella T8 and T. nelsoni) are presented. These were formulated based on the epidemiological factors, feeding habits of hosts and prevalence data gathered from the GKNP. We presume that the formulated sylvatic cycles may be extrapolated to similar national parks and wildlife protected areas in sub-Saharan Africa where the same host and parasite species are known to occur. The anecdotal nature of some of the presented data confirms the need for more intense epidemiological surveillance in national parks and wildlife protected areas in the rest of sub-Saharan Africa to unravel the epidemiology of Trichinella infections in these unique and diverse protected landscapes.
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Affiliation(s)
- Louis J. La Grange
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Department of Agriculture, Rural Development, Land and Environmental Affairs, Chief Directorate Veterinary Services, Veterinary Public Health Private Bag X11309 Mbombela 1200 South Africa
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University of KwaZulu-Natal, School of Life Sciences, Westville Campus Durban 4000 South Africa
| | - Samson Mukaratirwa
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University of KwaZulu-Natal, School of Life Sciences, Westville Campus Durban 4000 South Africa
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One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine P.O. Box 334 St Kitts Basseterre West Indies
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15
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Somaweera R, Nifong J, Rosenblatt A, Brien ML, Combrink X, Elsey RM, Grigg G, Magnusson WE, Mazzotti FJ, Pearcy A, Platt SG, Shirley MH, Tellez M, Ploeg J, Webb G, Whitaker R, Webber BL. The ecological importance of crocodylians: towards evidence‐based justification for their conservation. Biol Rev Camb Philos Soc 2020; 95:936-959. [DOI: 10.1111/brv.12594] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 02/20/2020] [Accepted: 02/25/2020] [Indexed: 12/27/2022]
Affiliation(s)
- Ruchira Somaweera
- CSIRO Health and Biosecurity Floreat WA 6014 Australia
- School of Biological Sciences, University of Western Australia Crawley WA 6009 Australia
| | - James Nifong
- IFAS‐Fort Lauderdale Research & Education Center, University of Florida Fort Lauderdale FL 33314 USA
| | - Adam Rosenblatt
- University of North Florida 1 UNF Drive, Jacksonville FL 32224 USA
| | - Mathew L. Brien
- Queensland Parks and WildlifeDepartment of Environment and Science Cairns QLD 4870 Australia
| | - Xander Combrink
- Department of Nature ConservationTshwane University of Technology Pretoria South Africa
| | - Ruth M. Elsey
- Louisiana Department of Wildlife and Fisheries Rockefeller Wildlife Refuge Grand Chenier LA 70643 USA
| | - Gordon Grigg
- School of Biological SciencesUniversity of Queensland St Lucia QLD 4072 Australia
| | - William E. Magnusson
- Coordenação da Biodiversidade, Instituto Nacional da Pesquisas da Amazônia Manaus 69067 Brazil
| | - Frank J. Mazzotti
- Department of Wildlife Ecology and ConservationEverglades Research and Education Center, University of Florida Gainesville FL 32603 USA
| | - Ashley Pearcy
- Section for Ecoinformatics and Biodiversity, Department of BioScienceAarhus University Aarhus Denmark
| | - Steven G. Platt
- Wildlife Conservation Society ‐ Myanmar Program Yangon Myanmar
| | - Matthew H. Shirley
- Tropical Conservation InstituteFlorida International University Miami FL 33181 USA
| | | | - Jan Ploeg
- Australian National Centre for Ocean Resources and Security, Innovation Campus, University of Wollongong Wollongong NSW 2522 Australia
| | - Grahame Webb
- Wildlife Management International Karama NT 0812 Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University Casuarina NT 0810 Australia
| | - Rom Whitaker
- The Madras Crocodile Bank Trust & Centre for Herpetology Mahabalipuram 603104 India
| | - Bruce L. Webber
- CSIRO Health and Biosecurity Floreat WA 6014 Australia
- School of Biological Sciences, University of Western Australia Crawley WA 6009 Australia
- Western Australian Biodiversity Science Institute Perth WA 6000 Australia
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16
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Somaweera R, Brien ML, Sonneman T, Didham RK, Webber BL. Absence of evidence is not evidence of absence: Knowledge shortfalls threaten the effective conservation of freshwater crocodiles. Glob Ecol Conserv 2019. [DOI: 10.1016/j.gecco.2019.e00773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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17
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Baker CJ, Franklin CE, Campbell HA, Irwin TR, Dwyer RG. Ontogenetic shifts in the nesting behaviour of female crocodiles. Oecologia 2019; 189:891-904. [PMID: 30868373 DOI: 10.1007/s00442-019-04382-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 03/07/2019] [Indexed: 11/26/2022]
Abstract
Body size and age are crucial factors influencing reproductive capacity and success. As females grow, their reproductive investment and success often increase due to improved overall physiological condition and experience gained through successive reproductive events. While much of this work has been conducted on birds and mammals, surprisingly little is known on how body size affects nesting decisions in other long-lived vertebrates. We monitored the movements and nesting behaviour of 57 wild female estuarine crocodiles Crocodylus porosus over a 10-year period (and across consecutive nesting seasons) using externally mounted satellite tags, implanted acoustic transmitters and a network of submerged acoustic receivers. Applying Hidden Markov models to the telemetry-derived location data revealed that female nesting behaviours could be split into three distinct states: (i) ranging movements within home ranges and at nesting sites; (ii) migrations to and from nesting sites; (iii) and nesting/nest guarding. We found that during migration events, larger females migrated further and remained away from dry season territories for longer periods than smaller individuals. Furthermore, not only were migratory movements stimulated by increases in rainfall, larger females migrated to nest sites at lower rainfall thresholds than smaller females. We provide some of the first evidence of body size influencing nesting decisions in an ectothermic vertebrate, with shifts likely resulting from an increased willingness to invest in nest protection among larger and more experienced females.
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Affiliation(s)
- Cameron J Baker
- The School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia
| | - Craig E Franklin
- The School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia
| | - Hamish A Campbell
- School of the Environment, Charles Darwin University, Darwin, 0810, Australia
| | - Terri R Irwin
- Australia Zoo, Steve Irwin Way, Beerwah, 4519, Australia
| | - Ross G Dwyer
- The School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia.
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18
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Staniewicz A, Youngprapakorn U, Jones G. First Report of Physiological Color Change in a Crocodilian. COPEIA 2018. [DOI: 10.1643/cp-17-711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Williamson SA, Evans RG, Manolis SC, Webb GJ, Reina RD. Ecological and evolutionary significance of a lack of capacity for extended developmental arrest in crocodilian eggs. ROYAL SOCIETY OPEN SCIENCE 2017; 4:171439. [PMID: 29308266 PMCID: PMC5750033 DOI: 10.1098/rsos.171439] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/15/2017] [Indexed: 05/14/2023]
Abstract
Hypoxia within the oviducts maintains embryonic arrest in turtles at the pre-ovipositional stage, which expands the timeframe over which nesting can occur without compromising embryo survival. The arrest can be extended post-oviposition through incubation of eggs in hypoxia. We determined whether crocodilian embryos have this same capacity. We also tested whether increased oxygen availability during incubation alters hatching success. We incubated freshly laid saltwater crocodile (Crocodylus porosus) eggs (N = 83) at 32°C in one of five treatments; control (normoxia; 21% O2), 3-day and 6-day hypoxia (1% O2), or 3-day and 6-day hyperoxia (42% O2). Incubation (approx. 82 days) was then completed in normoxia. There was a significant effect of treatment on survival of embryos through to hatching (p < 0.001). The hypoxic treatments resulted in almost no hatching (6.7% and 0% survival for the 3- and 6-day treatments, respectively), while the hyperoxic and control treatments resulted in normal to high hatching success (86.6%, 100% and 64.2% for the control, 3- and 6-day hyperoxic treatments, respectively). Unlike turtles, hypoxic incubation of crocodile eggs failed to delay development. Our results provide the first experimental evidence that, unlike turtles, crocodiles do not exhibit embryonic arrest when incubated under hypoxic conditions immediately following oviposition. An absence of embryonic arrest is of ecological and evolutionary significance, as it implies that crocodilians lack an ability to avoid adverse environmental conditions through delayed nesting and that, unlike turtles, embryonic arrest may not be a potential explanation for the lack of viviparity in the order Crocodylia.
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Affiliation(s)
- Sean A. Williamson
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
- Author for correspondence: Sean A. Williamson e-mail:
| | - Roger G. Evans
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria 3800, Australia
| | - S. Charlie Manolis
- Wildlife Management International Pty Limited, PO Box 530, Karama, Northern Territory 0813, Australia
| | - Grahame J. Webb
- Wildlife Management International Pty Limited, PO Box 530, Karama, Northern Territory 0813, Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory 0909, Australia
| | - Richard D. Reina
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
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20
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English LT. Variation in crocodilian dorsal scute organization and geometry with a discussion of possible functional implications. J Morphol 2017; 279:154-162. [DOI: 10.1002/jmor.20760] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/22/2017] [Accepted: 09/26/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Lauren T. English
- Department of Geology, Jackson School of Geosciences; The University of Texas at Austin; Austin Texas U.S.A
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21
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Nifong JC, Lowers RH. Reciprocal Intraguild Predation betweenAlligator mississippiensis(American Alligator) and Elasmobranchii in the Southeastern United States. SOUTHEAST NAT 2017. [DOI: 10.1656/058.016.0306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- James C. Nifong
- Kansas Cooperative Fish and Wildlife Research Unit, Division of Biology, Kansas State University, 104 Ackert Hall, Manhattan, KS 66506
| | - Russell H. Lowers
- Integrated Mission Support Services, Mail code IM-300, Kennedy Space Center, FL 32899
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22
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Russo J, Mateus O, Marzola M, Balbino A. Two new ootaxa from the late Jurassic: The oldest record of crocodylomorph eggs, from the Lourinhã Formation, Portugal. PLoS One 2017; 12:e0171919. [PMID: 28273086 PMCID: PMC5342183 DOI: 10.1371/journal.pone.0171919] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 01/27/2017] [Indexed: 11/18/2022] Open
Abstract
The Late Jurassic Lourinhã Formation is known for its abundant remains of dinosaurs, crocodylomorphs and other vertebrates. Among this record are nine localities that have produced either dinosaur embryos, eggs or eggshell fragments. Herein, we describe and identify the first crocodiloid morphotype eggs and eggshells from the Lourinhã Formation, from five occurrences. One clutch from Cambelas, composed of 13 eggs, eggshell fragments from Casal da Rola and Peralta, one crushed egg and eggshells from Paimogo North, and four crushed eggs as well as eggshell fragments from Paimogo South. We observed and confirmed diagnostic morphological characters for crocodiloid eggshells and which are consistent with a crocodylomorph affinity, such as the ellipsoidal shape, wedge-shaped shell units, triangular extinction under cross-polarized light, and tabular ultrastructure. This material is distinctive enough to propose two new ootaxa within the oofamily Krokolithidae, Suchoolithus portucalensis, oogen. and oosp. nov., for the material from Cambelas, the most complete clutch known for crocodiloid eggs, and Krokolithes dinophilus, oosp. nov., for the remaining material. These are the oldest crocodylomorph eggs known, extending the fossil record for this group to the Late Jurassic. Furthermore, except for the clutch from Cambelas, the material was found with theropod eggs and nests, in the other four occurrences, which seem to suggest some form of biological relationship, still unclear at this point.
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Affiliation(s)
- João Russo
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
- * E-mail:
| | - Octávio Mateus
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
| | - Marco Marzola
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Ausenda Balbino
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Departamento de Geociências, Universidade de Évora, Évora, Portugal
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23
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The Labile Limits of Forbidden Interactions. Trends Ecol Evol 2016; 31:700-710. [DOI: 10.1016/j.tree.2016.06.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/23/2016] [Accepted: 06/26/2016] [Indexed: 11/23/2022]
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24
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Implications of Scientific Collaboration Networks on Studies of Aquatic Vertebrates in the Brazilian Amazon. PLoS One 2016; 11:e0158413. [PMID: 27352247 PMCID: PMC4924867 DOI: 10.1371/journal.pone.0158413] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 06/15/2016] [Indexed: 11/19/2022] Open
Abstract
The quantity of wildlife extracted from the Amazon has increased in the past decades as a consequence of an increase in human population density and income growth. To evaluate the spatial distribution of studies on subsistence and/or commercial hunting conducted in the Brazilian Amazon, we selected eight mid-sized and large-bodied aquatic vertebrate species with a history of human exploitation in the region. We used a combination of searches in the gray and scientific literature from the past 24 years to provide an updated distributional map of studies on the target species. We calculated the distances between the study sites and the locations of the research institutes/universities that the first and last authors of the same study were affiliated to. For the period of 1990 to 2014, we found 105 studies on the subsistence and/or commercial hunting of aquatic vertebrates in the Brazilian Amazon in 271 locations that involved 43 institutions (37 Brazilian and 6 international). The spatial distribution of the studies across the Brazilian Amazon varied, but over 80% took place in the northeast and central Amazon, encompassing three States of the Legal Brazilian Amazon (Amazonas, 51.42%; Pará, 19.05%; and Amapá, 16.19%). Over half of the research study sites (52.91%) were within 500 km of the research institute/university of the first or last authors. Some research institutes/universities did not have any inter-institutional collaborations, while others collaborated with eight or more institutes. Some research institutes/universities conducted many studies, had an extensive collaboration network, and contributed greatly to the network of studies on Amazonian aquatic vertebrates. Our research contributes to the knowledge of studies on the subsistence and/or commercial hunting of the most exploited aquatic vertebrates of the Brazilian Amazon, illustrates the impact that collaboration networks have on research, and highlights potential areas for improvement and the generation of new collaborations.
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Size does matter: crocodile mothers react more to the voice of smaller offspring. Sci Rep 2015; 5:15547. [PMID: 26493940 PMCID: PMC4616036 DOI: 10.1038/srep15547] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/28/2015] [Indexed: 01/18/2023] Open
Abstract
Parental care is widespread in Archosaurs (birds, crocodilians, dinosaurs and pterosaurs), and this group provides a useful model for the evolution of parent-offspring interactions. While offspring signalling has been well-studied in birds, the modulation of parental care in crocodilians remains an open question. Here we show that acoustic communication has a key role in the dynamics of crocodilian’ mother-offspring relationships. We found embedded information about the emitter’s size in juvenile calls of several species, and experimentally demonstrated that Nile crocodile mothers breeding in the wild are less receptive to the calls of larger juveniles. Using synthetized sounds, we further showed that female’ reaction depends on call pitch, an important cue bearing size information. Changes in acoustic interactions may thus go with the break of maternal care as well as dispersal of juvenile crocodilians. This process could have characterized other archosaurs displaying rapid early growth such as dinosaurs and pterosaurs.
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Piña CI, Merchant ME, Verdade LM. Introduction: Reproduction in Crocodilians. SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2015. [DOI: 10.2994/sajh-d-15-00006.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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