In species within the genus, the albumen gland is very large.[2] The pallial oviduct evolved into a uterine brood, which releases shelled juvenile snails.[2] Compared to other aquatic snails, many species of Tylomelania are known to be the few groups of snails that are not hermaphroditic but rather dioecious.[9]
Comparison of apertural views of shells of twenty Tylomelania species are below, though are not of proper scale:
Ecology
Species in the genus Tylomelania are ovoviviparous.[2] Newly hatched snails of some species of Tylomelania measure nearly 2 cm (0.79 in) and are the largest newly hatched viviparous gastropods.[2]
^ abcdefghijklvon Rintelen, Bouchet P. & Glaubrecht M. (2007). "Ancient lakes as hotspots of diversity: a morphological review of an endemic species flock of Tylomelania (Gastropoda: Cerithioidea: Pachychilidae) in the Malili lake system on Sulawesi, Indonesia". Hydrobiologia592:11–94. doi:10.1007/s10750-007-0765-8.
^ abcdvon Rintelen T. & Glaubrecht M. (2008). "Three new species of the freshwater snail genus Tylomelania (Caenogastropoda: Pachychilidae) from the Malili lake system, Sulawesi, Indonesia". Zootaxa1852: 37–49. PDF.
^ abcdvon Rintelen T., Stelbrink B. Marwoto R. M. & Glaubrecht M. (2014). "A Snail Perspective on the Biogeography of Sulawesi, Indonesia: Origin and Intra-Island Dispersal of the Viviparous Freshwater Gastropod Tylomelania". PLoS ONE9(6): e98917. doi:10.1371/journal.pone.0098917.
^von Rintelen T., von Rintelen K. & Glaubrecht M. (2010). "The species flock of the viviparous freshwater gastropod Tylomelania (Mollusca: Cerithioidea: Pachychilidae) in the ancient lakes of Sulawesi, Indonesia: the role of geography, trophic morphology and colour as driving forces in adaptive radiation." pp. 485–512 in: Glaubrecht, M. & Schneider H. eds. (2010). Evolution in Action: Adaptive Radiations and the Origins of Biodiversity. Springer Verlag, Heidelberg, Germany.
^ abcvon Rintelen T. & Glaubrecht M. (2003). "New discoveries in old lakes: three new species of Tylomelania Sarasin & Sarasin, 1897 (Gastropoda: Cerithioidea: Pachychilidae) from the Malili lake system on Sulawesi, Indonesia". Journal of Molluscan Studies69(1): 3–17. doi:10.1093/mollus/69.1.3
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von Rintelen T., Wilson A. B., Meyer A. & Glaubrecht M. (2004). "Escalation and trophic specialization drive adaptive radiation of freshwater gastropods in ancient lakes on Sulawesi, Indonesia". Proceedings of the Royal Society B271: 2541–2549. doi:10.1098/rspb.2004.2842.