Nassarius obsoletus
Encyclopedia
The eastern mudsnail, Ilyanassa obsoleta, is a species
of sea snail
, a marine
gastropod mollusk in the family
Nassariidae
, the nassa mud snails.
which has a slightly rough exterior because the surface has intersecting weak spiral and axial ribs. The shell has an oval aperture
with a small notch or siphonal canal at the anterior end. The aperture has a smooth inner lip with a partial shield, and the outer lip is thin and smooth.
The exterior of the shell is a chalky white, but it is covered by a very dark brown, closely adhering periostracum
, except in areas of the shell where the periostracum has been eroded. The apex
of the shell is almost always eroded, and the shell is often quite damaged by the acidic properties of the mud in which the animal lives.
The maximum shell length is a little more than one inch, or about 28 mm.
to Georgia
in the United States
.
The nonindigenous distribution includes the West Coast
of the United States.
and inlets.
feeder, eating whatever is found in the film on top of the mud where it lives, including many microscopic marine plants.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of sea snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
, a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
gastropod mollusk in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Nassariidae
Nassariidae
Nassariidae, common name nassa mud snails , or dog whelks , are a taxonomic family of small to medium-sized sea snails, marine gastropod mollusks in the clade Neogastropoda.-Shell description:...
, the nassa mud snails.
Shell description
This species has a small shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
which has a slightly rough exterior because the surface has intersecting weak spiral and axial ribs. The shell has an oval aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
with a small notch or siphonal canal at the anterior end. The aperture has a smooth inner lip with a partial shield, and the outer lip is thin and smooth.
The exterior of the shell is a chalky white, but it is covered by a very dark brown, closely adhering periostracum
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
, except in areas of the shell where the periostracum has been eroded. The apex
Apex (mollusc)
Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...
of the shell is almost always eroded, and the shell is often quite damaged by the acidic properties of the mud in which the animal lives.
The maximum shell length is a little more than one inch, or about 28 mm.
Distribution
The indigenous distribution of this western Atlantic species is from Nova ScotiaNova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
to Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
The nonindigenous distribution includes the West Coast
West Coast of the United States
West Coast or Pacific Coast are terms for the westernmost coastal states of the United States. The term most often refers to the states of California, Oregon, and Washington. Although not part of the contiguous United States, Alaska and Hawaii do border the Pacific Ocean but can't be included in...
of the United States.
Habitat
This snail is very common on mud flats in the intertidal and shallow subtidal zones, in soundsSound (geography)
In geography a sound or seaway is a large sea or ocean inlet larger than a bay, deeper than a bight and wider than a fjord; or it may be defined as a narrow sea or ocean channel between two bodies of land ....
and inlets.
Feeding habits
This species is a detritusDetritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
feeder, eating whatever is found in the film on top of the mud where it lives, including many microscopic marine plants.
External links
- Rosenberg, G. (2010). Ilyanassa obsoleta (Say, 1822). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=467490 on 2010-07-15
- Goulding MQ. 2009. Cell Lineage of the Ilyanassa Embryo: Evolutionary Acceleration of Regional Differentiation during Early Development. PLoS ONEPLoS ONEPLoS ONE is an open access peer-reviewed scientific journal published by the Public Library of Science since 2006. It covers primary research from any discipline within science and medicine. All submissions go through an internal and external pre-publication peer review but are not excluded on the...
4(5): e5506. doi:10.1371/journal.pone.0005506 - Blakeman Smith, Journal of Molluscan Studies
- Kelaher et al., J Experimental Marine Biology and Ecology