A three-dimensional geometric morphometric analysis of the morphological transformation of Caiman lower jaw during post-hatching ontogeny.

Autor:	Fernandez Blanco MV; 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., Cassini GH; 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., Bona P; 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.
Jazyk:	angličtina
Zdroj:	PeerJ [PeerJ] 2023 Jul 12; Vol. 11, pp. e15548. Date of Electronic Publication: 2023 Jul 12 (Print Publication: 2023).
DOI:	10.7717/peerj.15548
Abstrakt:	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 . Competing Interests: The authors declare that they have no competing interests. Paula Bona is an Academic Editor for PeerJ. (© 2023 Fernandez Blanco et al.)
Databáze:	MEDLINE
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