Researchers from Indonesia's National Research and Innovation Agency (BRIN) have brought exciting news with the discovery of a new species of water snake called Hypsiscopus indonesiensis in Lake Towuti, South Sulawesi. This discovery brings the total number of snake species in Sulawesi to 60, enriching the biodiversity of the region.
The snake has a brownish-gray coloration with laterally flattened tails and a greater number of scale rows along the middle of its body. Interestingly, it has more ventral scales but fewer tail scales compared to other Hypsiscopus species. It also has a unique color pattern compared to other species.
H. indonesiensis is a freshwater snake known as the "flat-tailed water snake". According to researchers from the Center for Biosystematics and Evolutionary Research, Indonesian Institute of Sciences, BRIN, Amir Hamidy, this group of snakes typically inhabit freshwater environments and prey on small fish, tadpoles, or crabs.
Physically, they are relatively small, rarely exceeding 1 meter or 700 millimeters, and are found only in Lake Towuti. Their presence indicates a higher degree of endemism compared to H. matannensis.
"Further studies on its population and distribution are needed to assess its conservation status," Amir said in a written statement on Wednesday, January 26.
He explained that of the four species in the genus, three are found in Sulawesi, two of which are endemic. One is H. indonesiensis, which is found exclusively in Lake Towuti, while the other is H. matanensis, which is found in Lake Matano and several other regions in Sulawesi.
Amir noted that nearly 60 percent of all snakes in Sulawesi are endemic species, a figure much lower than in the Sundaland Islands. However, the level of endemism among Sulawesi snakes is higher.
"Sumatra has 127 species of snakes, 16 percent of which are endemic, while Kalimantan has 133 species (23 percent endemic), and Java and Bali have 110 species (6.4 percent endemic)," he explained.
Amir then told a story about Den Bosch's record in 1985, which noted the presence of 55 snake species in Sulawesi. But in 2005, the authors of "The Snakes of Sulawesi: A Field Guide to the Land Snakes of Sulawesi", Ruud de Lang and Gernot Vogel, revised the number to 52 species. Over time, seven new snake species have been successfully identified in Sulawesi, bringing the total number of snake species there to 59. These latest discoveries bring the diversity of land snake species in Sulawesi to 60 species.
Amir also shared an interesting story about the discovery of H. indonesiensis. According to him, the specimens of this snake came from six specimens collected in 2003 and one specimen collected in 2009, with a rather long span of about 16 years. Amir added that the identification process was delayed due to the limited number of specimens at the time.
He added that after 2019, members of the Indonesian Institute of Sciences (LIPI) at the time managed to collect fresh specimens from Lake Towuti, which greatly helped in validating the identification process. As a result, the discovery was published in the journal Treubia Volume 50 Number 1 in 2023.
As additional information, Sulawesi - an island in the Indo-Australian Archipelago - is known for its unique geological history and is a biodiversity hotspot for many species. The island has several ancient lakes that fragmented during the Pliocene epoch, including Lake Matano, Lake Towuti, and Lake Mahalona.