Ilyanassa obsoleta
Eastern Mudsnail
Characteristics:
The eastern mud snail is a benthic gastropod with a black or dark brown conical shell. Their size ranges from 1.5-3cm in length. That's about the size of a push pin!
Eastern Mudsnail
Characteristics:
The eastern mud snail is a benthic gastropod with a black or dark brown conical shell. Their size ranges from 1.5-3cm in length. That's about the size of a push pin!
Habitat: estuarine; the mudflats in the intertidal and shallow subtidal zones; brackish water habitats
Feeding habits: I. obsoleta are detritus eaters, meaning they eat organic debris that is formed from the decay of biotic material such as fish, algae, and crustacean remains.
I. obsoleta is able to eat sediment wholly! Its digestive tract breaks down organic matter leaving almost completely inorganic waste.
Life cycle:
Mud snail eggs hatch into larvae after 10 days. Larvae, immature snails, are free swimming and move with water currents. Larvae feed on phytoplankton 20-30 days before settling down on a substrate (hard surface). They remain dormant during the winter and do not grow until the summertime. These mud snails live for approximately 5 years.
Feeding habits: I. obsoleta are detritus eaters, meaning they eat organic debris that is formed from the decay of biotic material such as fish, algae, and crustacean remains.
I. obsoleta is able to eat sediment wholly! Its digestive tract breaks down organic matter leaving almost completely inorganic waste.
Life cycle:
Mud snail eggs hatch into larvae after 10 days. Larvae, immature snails, are free swimming and move with water currents. Larvae feed on phytoplankton 20-30 days before settling down on a substrate (hard surface). They remain dormant during the winter and do not grow until the summertime. These mud snails live for approximately 5 years.
Ilyanassa obsoleta with egg cases attached to Gracilaria.

Did you know... I. obsoleta are commonly used to keep aquarium cleans!
Scientific Classification:
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Family: Nassariidae
Genus: Ilyanassa
Species: I. obsoleta
Sources:
Cohen, A. N. 2005 Guide to the Exotic Species of San Francisco Bay. San Francisco Estuary Institute, Oakland, CA. www.exoticsguide.org.
Scheltema, R.S. 1964. Feeding habits and growth in the mud-snail Nassarius obsoletus. Chesapeake Science. Vol.5, No. 4, 161-166.