The Mesoamerican river turtle (scientific name Dermatemis mawii) is listed as a "critically endangered" species on the IUCN Red List of Endangered Species. This turtle is the last representative of a turtle family dating back 65 million years, and the shells of this unique species can reach up to 60 centimeters in length.
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The Mesoamerican river turtle is entirely aquatic and inhabits rivers, lagoons and other large wetlands in southern Mexico, Guatemala and Belize. It is almost impossible to move on land, so females build their nests on the flood waterline instead of on land. Their eggs only hatch after the water level drops. The species is heavily captured and consumed locally, especially on the eve of festivals, and high-intensity capture has led to a significant decline in populations in most of the areas where they live.
Protect species
The Mesoamerican river turtle is included in the CITES list and is protected or regulated in the regions and countries in which it lives. However, local enforcement is very weak and there is an urgent need to raise public awareness, promote population recovery and strengthen enforcement to prevent over-capture.
Habits of life
Mesoamerican river turtles lay their eggs twice a year, during spring and winter. Each female burrows in the river and lays about 20 eggs at a time. Fossils of Cretaceous mud turtles have been found in North America, Europe and Asia, but today there is only one member left in the mud turtle family: the Meso American River Turtle. The Meso American River Turtle (also known as the "Mesoamerican River Turtle") is a pure water turtle that has a well-established respiratory system and can stay in the water for a long time. They draw water from the mouth and nose, and the pharyngeal membrane on the back side of their nasal cavity is able to extract oxygen from the water.
Due to their long-term habitat in the water, the limbs of the Mesoamerican river turtle are slightly degraded, and because the limbs cannot bear the weight of the body, land crawling becomes quite difficult for them. Due to the local habit of preying on river turtles for food, the population of Mesoamerican river turtles in the local area has been greatly reduced, but the number is still decreasing due to the lack of strict protection measures by the local government. Food: Mesoamerican river turtles are carnivores, feeding on algae and aquatic plants, but also eat insects, snails, worms, small fish, crustaceans, and amphibians. It is a notable nocturnal turtle, unlike other turtles in its genus.
In the United States, since 1997, the Mesoamerican river turtle has been listed in the Endangered Species Act and needs to be protected as a candidate. Due to the changing climate of the southwest and the shrinking habitat, the impact on it is extremely obvious. Therefore, a decline in quantity is inevitable. Occurs at altitudes of 2042 m above sea level, in permanent streams, rivers, ponds, ditches and cavities. It is often found in woodlands, and only a few will enter temporary waters. In the Chiricahua Mountains in southeastern Arizona, 90 percent of the 580 Mesoamerican river turtles are captured in pools. 5% of individuals were captured in streams and ponds, and another 5% were captured on land. They also occasionally migrate from one body of water to another, which may symbolize that their temporarily infested ponds are not 8 kilometers away from permanent waters.
Reproductive characteristics
The Mesoamerican river turtle is based on the production of mature sperm in the vas deferens, the male usually takes 5-6 years, and the length of the dorsal carapace is generally 76-82 mm. At higher altitudes, sexual maturity is prolonged, with the smallest male dorsal carapace in the area measuring 91 mm but having grown for 8 years. Males have sunken ventral carapaces, a long and thick tail with hook-like spines at the ends, and two rows of thicker patches on the inside of the surface of the hind legs, with a body length of about 15.5 cm, which is obviously smaller than the length of the female's 17.5 cm. Females have flat and full belly and a short tail. Their testicles reached their maximum size in June and remained so until August. Recession period in September, reaching the smallest size in January or earlier in February. The length of the dorsal carapace corresponding to female sexual maturity is generally more than 93 mm, and the smallest female with eggs is 106 mm long and has an age of 5 years. According to Hulse's 1982 proposal, the ovarian cycle of females changes in March, and when the follicles begin to enlarge, the yolk also appears. The follicles grow rapidly until May, when the vesicles are about 13-15 mm in diameter and are able to ovulate. In August, these huge yolk vesicles have disappeared, and some with a diameter of 10-12.9 mm may remain until December, after which they begin to become smaller and smaller than 10 mm.
Hulse observed males in captivity in 1982, with courtship behavior occurring in March and mating in April. Iverson discovered a Mesoamerican river turtle in the wild on May 4, 1981, and such mating may also have occurred in the early spring. Spawning occurs from May to September, but at higher altitudes, it is also possible to enter July. It may be possible to lay 1-4 nests of eggs per year and the number of eggs is about 1-11. The number of eggs in the nest is bound to be related to the size of the female, the oval egg has a hard shell, the size range is (28.0-35.0× 13.8-19.0 mm, and the hatching usually occurs in August.
The artificially hatched larvae have a relatively flat, broad dorsal carapace, 22–28 mm long, as well as a central spine and two lateral spines. There is often a black patch above the edge of each edge shield, and the 10th edge shield is not significantly elevated, the ventral carapace is creamy, and there is a large black stripe in the middle that extends around along the seam line. Artificially hatched seedlings may have a pair of yellow stripes on either side of the head.