Morelet's crocodile
Morelet's crocodile '', also known commonly as the Mexican crocodile, the Belize crocodile, and el cocodrilo de pantano in Spanish, is a modest-sized crocodilian in the family Crocodylidae. The species is found only in the Atlantic regions of Mexico, Belize and Guatemala. It usually grows to about in total length. It is a species at least concern for extinction according to the International Union for Conservation of Nature.
The species has a fossil record in Guatemala.
Taxonomy and etymology
Morelet's crocodile was first discovered in 1850 in Mexico by the French naturalist Pierre Marie Arthur Morelet. The species was subsequently named after him in 1851 by French herpetologists Auguste Duméril and Gabriel Bibron. It was long confused with the American and Cuban crocodiles because of similar characteristics and an ambiguous type locality. It was not generally accepted as a separate species until the 1920s.Evolution
The genus Crocodylus likely originated in Africa and radiated outwards towards Southeast Asia and the Americas, although an Australia/Asia origin has also been considered. Phylogenetic evidence supports Crocodylus diverging from its closest recent relative, the extinct Voay of Madagascar, around 25 million years ago, near the Oligocene/Miocene boundary.Phylogeny
Below is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular, and stratigraphic data, as revised by the 2021 Hekkala et al. paleogenomics study using DNA extracted from the extinct Voay. Hall's New Guinea crocodile placement suggested in 2023 study by Sales-Oliveira ''et al.''Characteristics
Morelet's crocodile is similar in appearance and morphology to the Cuban crocodile and the larger American crocodile. When fully mature, Morelet's crocodile has a broad snout with 66–68 teeth. It is grayish-brown in color with dark bands and spots on the body and tail. This is similar to other crocodiles, like the American crocodile, but Morelet's crocodile is somewhat darker. Juvenile Morelet's crocodiles are bright yellow with dark bands. The iris is silvery brown. It has four short legs, giving it a rather sprawling gait, and a long tail, which is used for swimming. The hind feet are webbed. Despite its short legs, it is a fast runner.Morelet's crocodile is smaller than most other crocodiles, though it is larger than the dwarf crocodile. Adult males are typically larger than females. The average adult Morelet's crocodile is about in total length, with a typical length range of . Almost all Morelet's crocodiles in excess of are males, and at this advanced stage of maturity, the male goes through a significant change in skull osteological morphology as the skull appears to increase in broadness and robustness. Large adult males can attain a length of, anything in excess of this is considered exceptionally rare for this species, however the species has a maximum reported length of, with two other outsized specimens reportedly measuring, respectively. One mature adult specimen measuring and weighing had a bite force of. The weight of a large wild male crocodile is estimated to average around, although mass is likely much more in outsized individuals. One large male with a presumed total length of around weighed about. Another large individual measuring in length weighed.
Distribution and habitat
Morelet's crocodile can be found in freshwater habitats in Central America and along the Gulf of Mexico stretching through Belize, Guatemala, and Mexico. The Belizean pine forests are an example of the type of ecoregion in which it occurs.In its freshwater habitats, it prefers isolated areas that are secluded. This species of crocodile can mainly be found in freshwater swamps and marshes which are located inland, and in large rivers and lakes. Both of these habitats are forested to help add cover.
Morelet's crocodile can also be found along the coast in brackish waters and the grassy savannas on the Yucatán Peninsula. It becomes much more distributed during the rainy seasons when flooding occurs and it is easier for it to move elsewhere.
Juvenile Morelet's crocodiles live in very dense cover to protect themselves from other predators that might be in the area, and will remain there until they become older and able to fend for themselves. Adult crocodiles are known to dig out burrows during dry seasons in their area. The range of Morelet's crocodile can overlap with that of the American crocodile, which can sometimes lead to them being confused with one another. Morelet's crocodile generally prefers mainland freshwater habitats, while the American crocodile in the shared range is typically found in areas of saline mangrove, often on cays or atolls. Hybridization between the two species has been reported in Mexico and coastal Belize.
Recently, Morelet's crocodile has been introduced into the Rio Grande. Several newspaper outlets on the Mexican side of the border report of reptiles inhabiting the river appearing not to be the American alligator which is native to Texas, but the Morelet's crocodile which is native to Tamaulipas from San Fernando southward. Crocodiles have been seen in the cities of Matamoros, Reynosa and as far north as Nuevo Laredo. The sightings have prompted several municipal police departments to put up signs warning people about entering the river.