1
|
Fernandez Blanco MV, Cassini GH, Bona P. A three-dimensional geometric morphometric analysis of the morphological transformation of Caiman lower jaw during post-hatching ontogeny. PeerJ 2023; 11:e15548. [PMID: 37456902 PMCID: PMC10349558 DOI: 10.7717/peerj.15548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/22/2023] [Indexed: 07/18/2023] Open
Abstract
Shape ontogenetic changes of the lower jaw in crocodylians are poorly understood. In order to answer some questions related to the inter- and intraspecific morphological variation of the mandible of two extant Caiman species, we performed a three-dimensional geometric morphometric approach. For this purpose, we used landmarks and semilandmarks on two ontogenetic mandibular series of 48 and 15 post-hatching specimens of C. yacare and C. latirostris, respectively. We have also examined the relationship between these anatomical transformations and ontogenetic shifts in diet. We performed a principal component analysis (PCA) for the two species, and regression and partial least squares (PLS) analyses for each species, separately. As a result, species were segregated along the PC1 with specimens of C. yacare showing more gracile mandibles, and specimens of C. latirostris more robust ones. The PC2 and regression analyses showed an age gradient and represented ontogenetic shape changes. Adult caiman mandibles are higher and wider than juvenile ones, and shape changes are more conspicuous in C. latirostris. The PLS analyses showed a significant relationship between shape and diet. Morphological changes of the PLS1 of block-1 match with those of the regression analysis for both species. We have detected morphological transformations in areas where the musculature in charge of mandibular movements is attached. Common morphological changes occurring during ontogeny seem to reflect the same mechanical properties required for crushing and killing in both species, driven by an ontogenetic shift in the diet from invertebrates to vertebrates. Additionally, interspecific differences were also found to be correlated to ontogenetic changes in diet and could be related to dissimilar feeding mechanical requirements (e.g., stiffness and toughness of the item consumed), and to different habitat preferences. Robust mandibles would be more suitable for shallow and fully vegetated environments, as it can be seen in C. latirostris, whereas slender jaws seem to be more suitable for more aquatic species such as C. yacare.
Collapse
Affiliation(s)
- María Victoria Fernandez Blanco
- División Paleontología Vertebrados, Museo de La Plata, Unidades de Investigación Anexo II Museo, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Guillermo Hernán Cassini
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- División Mastozoología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ciudad Autónoma de Buenos Aires, Argentina
- Departamento de Ciencias Básicas, Universidad Nacional de Luján, Luján, Buenos Aires, Argentina
| | - Paula Bona
- División Paleontología Vertebrados, Museo de La Plata, Unidades de Investigación Anexo II Museo, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| |
Collapse
|
2
|
Balaguera-Reina SA, Angulo-Bedoya M, Moncada-Jimenez JF, Webster M, Roberto IJ, Mazzotti FJ. Update: Assessing the evolutionary trajectory of the Apaporis caiman ( Caiman crocodilus apaporiensis, Medem 1955) via mitochondrial molecular markers. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
The spectacled caiman (Caiman crocodilus) is currently considered to be a species complex due to the relatively high morphological and molecular diversity expressed across its range. One of the populations of interest, inhabiting the Apaporis River (Colombia), was described based on skull features as an incipient species (C. c. apaporiensis) and has been treated by some authors as a full species. Recent molecular work challenged this hypothesis, because relatively low mitochondrial molecular differentiation was found between the morphologically described Apaporis caiman and C. crocodilus (s.s.) Amazonian populations. Here, we present an update on the topic based on a larger molecular sample size and on analysis of expanded geometric morphometric data that include six newly collected skulls. Morphometric data support the existence of previously recognized morphotypes within the complex in Colombia and demonstrate that the newly collected material can be assigned to the classic Apaporis caiman morphotype. However, our expanded genetic analysis fails to find appreciable mitochondrial molecular divergence of the Apaporis caiman population from the C. c. crocodilus population (COI-CytB: Amazon Peru 0.17 ± 0.06%, CytB-only: Caquetá River Colombia 0.08 ± 0.07%). The Apaporis caiman is interpreted to be a phenotypically distinct member of the cis-Andean C. crocodilus metapopulation that has not yet achieved (or may not be undergoing at all) appreciable genetic differentiation. Thus, it should not be considered a fully independent evolutionary lineage, nor given full species rank.
Collapse
Affiliation(s)
- Sergio A Balaguera-Reina
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida , Fort Lauderdale, FL , USA
- Programa de Biología Ambiental, Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué , Ibagué , Colombia
| | | | - Juan F Moncada-Jimenez
- Programa de Biología, Facultad de Ciencias, Universidad de Tolima, Calle 42 #1B-1 Barrio Santa Helena, Ibagué, 730001 , Colombia
| | - Mark Webster
- Department of the Geophysical Sciences, University of Chicago , IL , USA
| | - Igor J Roberto
- Laboratorio de Biologia e Ecologia de Animais Silvestres (LABEAS), Universidade Federal do Cariri (UFCA) , Brejo Santo, Ceará, 69077-000 , Brazil
| | - Frank J Mazzotti
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida , Fort Lauderdale, FL , USA
| |
Collapse
|
3
|
Falcón-Espitia NG, Jerez A. EL CRÁNEO DE Caiman crocodilus fuscus: VARIACIONES ALOMÉTRICAS Y ONTOGENÉTICAS. ACTA BIOLÓGICA COLOMBIANA 2022. [DOI: 10.15446/abc.v27n3.90810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Las variaciones ontogenéticas en el cráneo ofrecen información del crecimiento y la ecología trófica en Crocodilia. Por lo tanto, analizamos las variaciones ontogenéticas de la forma y elementos óseos del cráneo en C. c. fuscus. Encontramos un efecto alométrico y cambios en la forma, ya que varía de un cráneo longirostrino en las crías a uno brevirostrino en subadultos y adultos. Se observó el ensanchamiento de la base del escamoso, del cuadratoyugal, del proceso lateral del pterigoides, del proceso retroarticular del articular y el desarrollo de una cresta dorsal en el surangular. Estos cambios, probablemente estarían relacionados con variaciones en la dieta durante la ontogenia, y tienen implicaciones ecológicas que deben ser consideradas en el estudio de la evolución y conservación de estas subespecies.
Collapse
|
4
|
Carr AN, Nestler JH, Vliet KA, Brochu CA, Murray CM, Shirley MH. Use of continuous cranial shape variation in the identification of divergent crocodile species of the genus Mecistops. J Morphol 2021; 282:1219-1232. [PMID: 33945166 DOI: 10.1002/jmor.21365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 04/22/2021] [Accepted: 05/02/2021] [Indexed: 11/10/2022]
Abstract
The discovery of cryptic biodiversity has blossomed under the advancements of genetic techniques, but species identification via morphology remains crucial to effective conservation efforts. In this study, we tested the use of continuous cranial shape variation in distinguishing the two living species of Mecistops: the West African slender-snouted crocodile (M. cataphractus) and the Central African slender-snouted crocodile (M. leptorhynchus). Using a combination of geometric morphometric characters and ratios of linear measurements, we identified statistically significant variation in cranial bone and overall skull shape of mature individuals that corroborates existing molecular and discrete morphological evidence for two distinct, extant species within Mecistops. Specifically, variation in the shape of the nasal appears particularly diagnostic, while ratios involving metrics of snout length to snout width at the premaxillary notch offer distinguishing features easily measured in the field. Because of the complementary results and applications of the morphometric and cranial ratio analyses, we argue that both methodologies remain relevant to species identification. Moreover, we recommend continued cooperation between geneticists and morphologists in diagnosing species of conservation concern.
Collapse
Affiliation(s)
- Amanda N Carr
- Department of Wildlife Ecology & Conservation, University of Florida, Gainesville, Florida, USA
| | | | - Kent A Vliet
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Christopher M Murray
- Department of Biological Sciences, Southeastern Louisiana University, Hammond, Louisiana, USA
| | - Matthew H Shirley
- Institute of Environment, Florida International University, North Miami, Florida, USA.,Project Mecistops, Sarasota, Florida, USA
| |
Collapse
|
5
|
Balaguera-Reina SA, Vargas-Ramírez M, Ordóñez-Garza N, Hernández-González F, Densmore LD. Unveiling the mystery: assessing the evolutionary trajectory of the Apaporis caiman population (Caiman crocodilus apaporiensis, Medem 1955) via mitochondrial molecular makers. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The Apaporis caiman (Caiman crocodilus apaporiensis) has been of particular interest due to its highly differentiated morphology. However, no molecular research has been done to clarify its taxonomy. We characterized the genetic variation within C. crocodilus by assessing the evolutionary trajectory of Apaporis caiman populations using mitochondrial molecular markers. We collected ten Apaporis caiman samples from the middle basin of the Apaporis River, Colombia, sequenced two mitochondrial genes [cytochrome oxidase I (COI) and cytochrome B (CytB)], and analysed them together with all available sequences from homologous gene fragments at GenBank for the species. Phylogenetic reconstructions revealed three main clades clearly differentiated across the C. crocodilus complex. These clades matched genetically and geographically with three of the four subspecies currently recognized (C. c. chiapasius, C. c. fuscus and C. c. crocodilus). However, we found low to almost non-existent genetic differentiation between C. c. crocodilus and the until-now morphologically recognized C. c. apaporiensis, suggesting that the latter is part of the genetic spectrum present within C. c. crocodilus. We reject the hypothesis of an expected elevated level of genetic variation due to isolation (supported by morphological differentiation) and support the idea of Apaporis caiman populations as a C. crocodilus ecomorph.
Collapse
Affiliation(s)
- Sergio A Balaguera-Reina
- Programa de Biología Ambiental, Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Ibagué, Colombia
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Mario Vargas-Ramírez
- Estación de Biología Tropical Roberto Franco (EBTRF), Universidad Nacional de Colombia, Villavicencio, Meta, Colombia
- Grupo Biodiversidad y Conservación Genética, Instituto de Genética, Universidad Nacional de Colombia, Bogotá DC, Colombia
| | - Nicté Ordóñez-Garza
- Natural Science Research Laboratory, Museum of Texas Tech University, Lubbock, TX, USA
| | - Felipe Hernández-González
- Programa de Biología Ambiental, Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Ibagué, Colombia
- Programa de Biología, Facultad de Ciencias, Universidad de Tolima, Barrio Santa Helena, Ibagué, Colombia
| | | |
Collapse
|
6
|
Roberto IJ, Bittencourt PS, Muniz FL, Hernández-Rangel SM, Nóbrega YC, Ávila RW, Souza BC, Alvarez G, Miranda-Chumacero G, Campos Z, Farias IP, Hrbek T. Unexpected but unsurprising lineage diversity within the most widespread Neotropical crocodilian genus Caiman (Crocodylia, Alligatoridae). SYST BIODIVERS 2020. [DOI: 10.1080/14772000.2020.1769222] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Igor J. Roberto
- Laboratory of Animal Genetics and Evolution (LEGAL), Federal University of Amazonas (UFAM), Manaus, AM, Brazil
- Post-Graduate Program in Zoology, Institute of Biological Sciences, Federal University of Amazonas (UFAM), Manaus, AM, Brazil
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - Pedro S. Bittencourt
- Laboratory of Animal Genetics and Evolution (LEGAL), Federal University of Amazonas (UFAM), Manaus, AM, Brazil
| | - Fabio L. Muniz
- Laboratory of Animal Genetics and Evolution (LEGAL), Federal University of Amazonas (UFAM), Manaus, AM, Brazil
| | - Sandra M. Hernández-Rangel
- Laboratory of Animal Genetics and Evolution (LEGAL), Federal University of Amazonas (UFAM), Manaus, AM, Brazil
| | | | - Robson W. Ávila
- Department of Biology, Federal University of Ceará (UFC), Fortaleza, CE, Brazil
| | - Bruno C. Souza
- Chico Mendes Institute for Biodiversity Conservation (ICMBio), Boa Vista, RR, Brazil
| | - Gustavo Alvarez
- Wildlife Conservation Society (WCS), Bolivia Program, La Paz, Bolivia
| | | | - Zilca Campos
- Wildlife Laboratory, Brazilian Agricultural Research Corporation (EMBRAPA) Pantanal, Corumbá, MS, Brazil
| | - Izeni P. Farias
- Laboratory of Animal Genetics and Evolution (LEGAL), Federal University of Amazonas (UFAM), Manaus, AM, Brazil
| | - Tomas Hrbek
- Laboratory of Animal Genetics and Evolution (LEGAL), Federal University of Amazonas (UFAM), Manaus, AM, Brazil
| |
Collapse
|
7
|
Abstract
Abstract
Advances in molecular biology and genetics are revealing that many recognized crocodylian species are complexes of two or more cryptic species. These discoveries will have a profound impact on interpretation of the crocodyliform fossil record. Our understanding of ranges of intraspecific variation in modern crocodylian morphology may be based on multiple species and thus express both intraspecific and interspecific variation. This raises questions about our ability to recognize modern species in the fossil record, and it also indicates that specimens from disparate localities or horizons may represent not single widespread species, but multiple related species. Ranges of variation in modern species require a thorough re-evaluation, and we may have to revisit previous perceptions of past crocodyliform diversity, rates of evolution or anagenetic lineages in stratigraphic succession. These challenges will not be unique to those studying crocodyliforms and will require sophisticated approaches to variation among modern and fossil specimens.
Collapse
Affiliation(s)
- Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA, USA
| | - Colin D Sumrall
- Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, USA
| |
Collapse
|
8
|
Cardini A, Chiapelli M. How flat can a horse be? Exploring 2D approximations of 3D crania in equids. ZOOLOGY 2020; 139:125746. [PMID: 32086141 DOI: 10.1016/j.zool.2020.125746] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 01/13/2023]
Abstract
Quantitative analyses of morphological variation using geometric morphometrics are often performed on 2D photos of 3D structures. It is generally assumed that the error due to the flattening of the third dimension is negligible. However, despite hundreds of 2D studies, few have actually tested this assumption and none has done it on large animals, such as those typically classified as megafauna. We explore this issue in living equids, focusing on ventral cranial variation at both micro- and macro-evolutionary levels. By comparing 2D and 3D data, we found that size is well approximated, whereas shape is more strongly impacted by 2D inaccuracies, as it is especially evident in intra-specific analyses. The 2D approximation improves when shape differences are larger, as in macroevolution, but even at this level precise inter-individual similarity relationships are altered. Despite this, main patterns of sex, species and allometric variation in 2D were the same as in 3D, thus suggesting that 2D may be a source of 'noise' that does not mask the main signal in the data. However, the picture that emerges from this and other recent studies on 2D approximation of 3D structures is complex and any generalization premature. Morphometricians should therefore test the appropriateness of 2D using preliminary investigations in relation to the specific study questions in their own samples. We discuss whether this might be feasible using a reduced landmark configuration and smaller samples, which would save time and money. In an exploratory analysis, we found that in equids results seem robust to sampling, but become less precise and, with fewer landmarks, may slightly overestimate 2D inaccuracies.
Collapse
Affiliation(s)
- Andrea Cardini
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via Campi 103, 41125, Modena, Italy; Centre for Forensic Anatomy and Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
| | - Marika Chiapelli
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via Campi 103, 41125, Modena, Italy
| |
Collapse
|