Page 286 - (DK) Ocean - The Definitive Visual Guide

284 ANIMAL LIFE

CLASS GASTROPODA orange foot CLASS GASTROPODA Easily distinguished from most other
with gastropods by the conical shape of its
Common Limpet greenish Top Shell spiral shell, the top shell moves slowly
tint
over reef flats and coral rubble, feeding
Patella vulgata Tectus niloticus on algae. Demand for its flesh and
DIAMETER LENGTH pretty shell has led to declining
1
2 / 2 in (6 cm) 6 in (16 cm) numbers, especially in the Philippines,
HABITAT HABITAT due to unregulated harvesting. It has,
Rocks on high shore to conical Intertidal and shallow however, been successfully introduced
sublittoral zone shell subtidal areas, reef flats
to 23 ft (7 m) elsewhere in the Indo-Pacific, such
as French Polynesia and the Cook
MUSCULAR FOOT
DISTRIBUTION Northeastern Atlantic from Arctic The common limpet’s muscular foot, seen here DISTRIBUTION Eastern Indian Ocean, western and Islands, from where some original sites
Circle to Portugal southern Pacific are being restocked.
from below, holds it firmly to its rock,
regardless of the strength of the waves.
Abundant on rocks from the high
to the low water mark, the common taller shells allow for better water CLASS GASTROPODA
limpet is superbly adapted to shore retention during periods of exposure.
life. A conical shell protects it from Limpets travel slowly during low tide, Red Abalone
predators and the elements. Limpets covering up to 24 in (60 cm) using
living at the low water mark are contractions of their single foot. They Haliotis rufescens
buffeted by the waves and so require graze on algae from rocks using a LENGTH
smaller, flatter shells than those living radula (a rasplike structure), which has 6–8 in (15–20 cm)
at the high water mark, where wider, teeth reinforced with iron minerals. HABITAT
Rocks from low tide
mark to 100 ft (30 m)
DISTRIBUTION East Pacific coasts from southern three to five clearly visible holes in
Oregon, US to Baja California, Mexico the shell, through which water flows
for respiration.These are filled and
The largest of the abalone species, replaced with new holes as the
the red abalone is so called because abalone increases in size. Sea otters
of the brick-red color of its thick, are one of the red abalone’s main
roughly oval shell. There is an arc of predators, along with human divers.

CLASS GASTROPODA
HIDING FROM
RETURNING HOME Venus Comb
Limpets gradually grind a “scar” into their VIEW
anchor spot on the rock, to aid their grip Murex pecten
and help retain water. A mucus trail leads There are times when the Venus
LENGTH
them back to the spot. Up to 3 in (8 cm) comb buries itself just below the
surface of the sea floor, displacing
HABITAT the sand with movements of its
Tropical warm waters to
650 ft (200 m) muscular foot. However, it leaves
the opening of its tubular inhalant
siphon above the sand’s surface so
CLASS GASTROPODA CLASS GASTROPODA DISTRIBUTION Eastern Indian Ocean and western that it can draw water into its
Pacific
Zebra Nerite Dog Whelk mantle cavity to obtain oxygen
and to “taste” the water for the
The tropical carnivorous snail known
Puperita pupa Nucella lapillus as the Venus comb has a unique and presence of prey.
LENGTH LENGTH spectacular shell. There are rows of
1
1
Up to / 2 in (1 cm) Up to 2 / 2 in (6 cm) long, thin spines along its longitudinal
HABITAT HABITAT ridges, which continue onto the
Rocky tide pools Middle and lower rocky narrow, rodlike, and very elongated
shores siphon canal. The exact function of
these spines is unknown, but they are
DISTRIBUTION Caribbean, Bahamas, Florida DISTRIBUTION Northwestern and northeastern thought to be either for protection or
Atlantic to prevent the snail from sinking into HALF BURIED
The small, rounded, smooth, black- the soft substrate on which it lives. Its The spines of this Venus comb can be seen
and-white striped shell of the zebra One of the most common rocky shore body is tall and columnar so that it can sticking out of the sand. The siphon is visible
nerite is typical of the species, but in gastropods, the dog whelk has a thick, lift its cumbersome shell above the to the right of the picture.
examples from Florida the shell is heavy, sharply pointed spiral shell. sediment to move in search of food.
sometimes more mottled or speckled The shell’s exact shape depends on its
with black. These gastropods are most exposure to wave action, and its color
active during the day, when they feed depends on diet. Dog whelks are
on microorganisms such as diatoms voracious predators, feeding mainly on
and cyanobacteria, but if they become barnacles and mussels. Once the prey
too hot or they are exposed at low has been located, the whelk uses its
tide, they cluster together, withdraw radula to bore a hole in the shell of
into their shells, and become inactive. its prey before sucking out the flesh.
This may be a mechanism for
OCEAN LIFE separate males and females of zebra
preventing excessive water loss.
Unusually for gastropods, there are
nerites and fertilization of the eggs
occurs internally. The males use their
penis to deposit sperm into a special
storage organ inside the female. Later,
she lays a series of small white eggs
that hatch into planktonic larvae.