Tylomelania


Tylomelania is a genus of freshwater snails which have an operculum, aquatic gastropod mollusks in the family Pachychilidae. In the aquarium hobby, snails from this genus are commonly known as "rabbit snails".
A sister group of Tylomelania is genus Pseudopotamis. Tylomelania and Pseudopotamis split in the Middle Miocene c. 19.5 Mya.

Distribution

These freshwater snails are endemic to Sulawesi in Indonesia, with the vast majority restricted to Lake Poso and the Malili Lake system.
They probably cannot live at an altitude above about 700 m.

Species

There were known 34 described species in 2005. Thomas von Rintelen with colleagues described 15 new species of Tylomelania in 2003–2008.
Tylomelania species diversification started in c. 5.4 Mya and was probably caused by the late Miocene and Pliocene orogeny.
Species within the genus Tylomelania include:
In species within this genus, the albumen gland is very large. Pallial oviduct evolved into an uterine brood.
Comparison of apertural views of shells of twenty Tylomelania species :

Ecology

Species in the genus Tylomelania are ovoviviparous. Newly hatched snails of some species of Tylomelania measure nearly 2 cm and are the largest newly hatched viviparous gastropods.