Aporrhais occidentalis
Encyclopedia
Arrhoges occidentalis, common name
the American pelicanfoot, is a species
of medium-sized sea snail
, a marine
gastropod mollusk in the family
Aporrhaidae
, the pelican's foot snails or pelican's foot shells.
Morton (1956) considers Arrhoges occidentalis as the most primitive member of the family Aporrhaidae.
and along the North American coast from Labrador
and Massachusetts
to off North Carolina
. It lives on sand or mud at depths between 10 to 550 m. Off North Carolina it is usually found in deep water.
contains 20-25 folds. The aperture
is long and narrow. It has a thick, shiny white outer lip that suggests a triangular, winglike expansion. The parietal wall and the outer lip are thickened internally. The small operculum
is horny and claw-shaped. It is narrow and has smooth edges.
The maximum recorded shell
length is 70 mm.
to probe in muddy gravel or in sand, searching for food. It feeds on macro algae particles, benthic diatoms Pleurosignia sp., on detritus
and also remains of animal matter, such as sponge spicule
s.
s (but self-ferilization is usually prevented due to various mechanisms). Copulation occurs at night from March to April. The small eggs are deposited in the sand or on debris singly or in small groups by the female. The larvae hatch as free-swimming plankton-feeding individuals.
Dall, 1902, the crab Cancer irrotatus Say, 1817 and the Atlantic wolffish Anarhichas lupus Linnaeus, 1758 . The well-developed outer shell lips of the adults give them an adequate protection against the claws of Cancer irrotatus.
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
the American pelicanfoot, is a species
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 medium-sized sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
, 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...
Aporrhaidae
Aporrhaidae
Aporrhaidae, common name the pelican's foot snails, is a taxonomic family of sea snails. The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 categorizes Aporrhaidae as marine gastropod mollusks in the clade Littorinimorpha....
, the pelican's foot snails or pelican's foot shells.
Morton (1956) considers Arrhoges occidentalis as the most primitive member of the family Aporrhaidae.
Distribution
This species is distributed infralittoral, circalittoral and bathyal in the North West Atlantic OceanAtlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
and along the North American coast from Labrador
Labrador
Labrador is the distinct, northerly region of the Canadian province of Newfoundland and Labrador. It comprises the mainland portion of the province, separated from the island of Newfoundland by the Strait of Belle Isle...
and Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
to off North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
. It lives on sand or mud at depths between 10 to 550 m. Off North Carolina it is usually found in deep water.
Description
The gray to yellowish-white shell is strong and has a high, pointed spire. Its length is between 4.1 and 6.4 cm (1⅝I -2½ inch) The shell has 8-10 well-rounded whorls, each of which shows many strong, curved axial ribs crossed by crowded, fine spiral threads (that may be worn away) on the outer layer. The body whorlBody whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
contains 20-25 folds. The 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....
is long and narrow. It has a thick, shiny white outer lip that suggests a triangular, winglike expansion. The parietal wall and the outer lip are thickened internally. The small operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
is horny and claw-shaped. It is narrow and has smooth edges.
The maximum recorded shell
Gastropod 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...
length is 70 mm.
Feeding patterns
The animal uses its proboscisProboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
to probe in muddy gravel or in sand, searching for food. It feeds on macro algae particles, benthic diatoms Pleurosignia sp., on detritus
Detritus
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...
and also remains of animal matter, such as sponge spicule
Spicule
Spicules are tiny spike-like structures of diverse origin and function found in many organisms, such as the copulatory spicules of certain nematodes or the grains on the skin of some frogs.In sponges, spicules perform a structural function....
s.
Life cycle
Sexes are separate or simultaneous hermaphroditeHermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...
s (but self-ferilization is usually prevented due to various mechanisms). Copulation occurs at night from March to April. The small eggs are deposited in the sand or on debris singly or in small groups by the female. The larvae hatch as free-swimming plankton-feeding individuals.
Predators
The American pelicanfoot has as potential predators the gastropod Colus stimpsoniColus stimpsoni
Colus stimpsoni, common name the Stimpson's colus, is a species of sea snail, a marine gastropod mollusk in the family Buccinidae, the true whelks....
Dall, 1902, the crab Cancer irrotatus Say, 1817 and the Atlantic wolffish Anarhichas lupus Linnaeus, 1758 . The well-developed outer shell lips of the adults give them an adequate protection against the claws of Cancer irrotatus.
Further reading
- Harald E. Rehder, Field Guide to North American Seashells, National Audubon Society, Ninth printing, 1996, ISBN 0-394-51913-2