While puberty is an animal commonality, little is known of its timing or process in crocodylians. Males copulate with an intromittent phallus that has a distinct glans morphology which directly interacts with the female cloaca, putatively effecting effective semen transfer and ultimately increased fecundity. Here we present, during the Morelet's crocodile lifecycle, a well-defined body length (65 cm snout-vent length) inflection point that marks a subsequent increase of phallic glans growth rates. Putatively, this postpubescent growth produces a copulatory-effective phallus. While not as robust of a trend as snout-vent length, this growth inflection concomitantly begins with a body condition index (CI = BM/SVL ) between 2.0 and 2.5 and is most distinct above a CI of 2.5. Also, in males, this 65 cm size threshold also aligns with the initiation of more robust growth in caniniform alveoli associated with prominent maxillary and mandibular teeth. This inflection was not observed in females, thus marking a sexual dimorphism that begins to present with the onset of puberty. This bodily manifestation of puberty other than those changes observed in the reproductive tracts is a novel observation for crocodylians and lays a foundation for further study among species of how changing endocrine signaling within sexually maturing males may also influence a broader range of secondary sex characteristics.
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http://dx.doi.org/10.1002/jez.2325 | DOI Listing |
Animals (Basel)
September 2024
Biología de la Conducta, Instituto de Neuroetología, Universidad Veracruzana, Dr. Luis Castelazo s/n Col. Industrial Ánimas, Xalapa 91190, Veracruz, Mexico.
Environ Pollut
September 2022
Department of Systematics and Aquatic Ecology. El Colegio de la Frontera Sur (ECOSUR), Av. Centenario Km 5.5, 77014, Chetumal, Quintana Roo, Mexico. Electronic address:
Environmental pollution by metals has repercussions on wildlife health. It is known that some metals can have an influence on the neuroendocrine stress response, and at the same time, metals have pro-oxidant effects that can overwhelm the antioxidant system and cause oxidative stress. This study evaluates the association of metals with neuroendocrine stress activity and biomarkers of oxidative stress in 42 captive female Morelet's crocodiles (Crocodylus moreletii).
View Article and Find Full Text PDFPeerJ
January 2023
School of Science, Engineering and Environment, University of Salford, Salford, Greater Manchester, United Kingdom.
Estimates of animal abundance provide essential information for population ecological studies. However, the recording of individuals in the field can be challenging, and accurate estimates require analytical techniques which account for imperfect detection. Here, we quantify local abundances and overall population size of Morelet's crocodiles () in the region of Calakmul (Campeche, Mexico), comparing traditional approaches for crocodylians (Minimum Population Size-MPS; King's Visible Fraction Method-VFM) with binomial mixture models based on Poisson, zero-inflated Poisson (ZIP) and negative binomial (NB) distributions.
View Article and Find Full Text PDFEcotoxicol Environ Saf
February 2022
University of Antwerp, Systemic Physiological and Ecotoxicological Research Group (SPHERE), Groenenborgerlaan 171, 2020 Antwerp, Belgium. Electronic address:
Crocodylus moreletii (Morelet's crocodile) and Crocodylus acutus (American crocodile) are generalist, apex predators of subtropical aquatic habitats in Central America. As top predators, crocodiles may be exposed to high levels of micro pollutants, such as trace elements via bioaccumulation that enter the food web as a consequence of human activities. As such, the status of their population can be considered indicative of that of the entire ecosystem - i.
View Article and Find Full Text PDFMol Phylogenet Evol
November 2020
Department of Biology, University of British Columbia, 3247 University Way, Kelowna V1V 1V7, British Columbia, Canada.
Extant species in the order Crocodylia are remnants of an ancient lineage of large-bodied archosaur reptiles. Despite decades of systematic studies, phylogenetic relationships among members of the genus Crocodylus (true crocodiles) in the Neotropics are poorly understood. Here we estimated phylogenomic relationships among the four extant Crocodylus species in the Americas.
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