JOIN USSampling has been carried out over the past 10 years in the Los Tuxtlas region, and these species have not been found among the local fauna, said biologist Hugo Reynoso, a researcher with the National Autonomous University of Mexico (UNAM).
However, it is not known if they have become extinct in the zone or simply have not been encountered, he said.
"A decade is an important sampling period during which not to have found them," he declared.
Reynoso said the 155,122 hectares of forest in Los Tuxtlas, located in the Gulf of Mexico coastal state of Veracruz, have suffered from severe "fragmentation" due to deforestation.
"Unfortunately, it seems to be that... the amphibians and reptiles are disappearing, and only some very resistant species are surviving," he said. Reynoso said those animals are in a "very important" group because they are the first vertebrates to disappear from the ecological systems, given that they depend on the habitat to reproduce and do not have the same ability to move elsewhere as birds, "who if they don't like it they go to another place".
In Los Tuxtlas, mammals larger than badgers, raccoons, opossums and howler monkeys have not been found, he said, adding that larger mammals such as jaguars and tapirs were also not to be seen.
The scientist said the forests of southeastern Mexico are one of the most diverse land environments on the planet, containing between 60 percent and 80 percent of the currently-known plant and animal species. However, between 1960 and 1990 those areas "suffered a significant rate of deforestation".