New Ancient Alligator Species Discovered in Small Pond

A fossil unearthed in a small pond in 2005 has now been linked to a new ancient species of alligator after nearly two decades of research.

The fossil was first discovered in Nakhon Ratchasima, the capital of Nakhon Ratchasima province and the third largest city in Thailand, under six-and-a-half feet of sandy sediment after a group of villagers dug out a small pond to search for fossils. The alligator-like fossils contained a skull, two jawbones and five other bone fragments, according to The Bangkok Post.

A resident discovered the bones, which were then sent to the nation's Department of Mineral Resources. After years of research, scientists recruited from Germany have determined that the fossils are from a species of alligator that was native to the area.

The fossils were dated 230,000 years ago in the Pleistocene period. The Pleistocene period is a time period that includes the last ice age and ended roughly 11,700 years ago.

Researchers compared the fossils to Alligator mississippiensis, also known as the American alligator, and Alligator sinensis, the Chinese alligator. The fossils most closely resembled the bone structure of the Chinese alligator, and the study revealed that the two species are related and likely share an ancestor that lived in the Mekong-Chao Phraya River system.

Researchers named the new species Alligator munensis since it was discovered in the Mun River basin. Their findings were published in the scientific journal Nature in July.

"...its highly distinct morphology warrants naming a new species and at the same time several shared several derived characteristics suggest close relationship to Alligator sinensis," researchers wrote in the study.

While Alligator munensis shares several qualities with Alligator sinensis and Alligator mississippiensis, there were some distinct differences as well, particularly in the bone structure of the skull. Researchers discovered that Alligator munensis had "well-developed jaw adductor muscles and strong bite force consistent with a crushing type of dentition."

Gustavo Darlim de Oliveira, one of the authors of the study, told Newsweek that Alligator munensis had several features that differed from all other alligator species, extinct or living. The new species had a short, tall snort with small, rounded nostrils positioned far away from the tip of the snout. There were only 12 tooth sockets on its upper jaw, making it the alligator species with the fewest number of teeth. Also, the area between the alligator's eyes was curved, which differs from the flat surface observed in other alligator species.

The fossil suggested that the alligator had large teeth in the back of its mouth consistent with crushing hard-shelled prey, such as snails.

Researchers also wrote that the new extinct species had reduced nostril size, which was unlike other crocodilians with its "small, rounded external nares that are posterodorsally retracted and are bisected by a wide internarial bar."

The discovery is consistent with Alligator munensis likely not being a marine species given the "depositional environment and geographic origin of the fossil specimen."

Fossils belonging to wild water buffalo and turtles also were found at the same site.

Both the American alligator and Chinese alligator are protected species, with the latter being the most endangered crocodilian species in the world. The National Zoo describes the Chinese alligator as being one of the few alligators outside of the Americas. The American alligator also is threatened and is federally protected by the Endangered Species Act.

Update 10/19/2023, 11:17 a.m. ET: This article was updated with comment from Gustavo Darlim de Oliveira.