| Abdomen |
the posterior section of the body, behind the thorax
or the cephalothorax |
| Acoelomate |
any organism that lacks a cavity between the body
wall and the digestive tract |
| Adductor muscle |
a muscle whose function is to close a bivalved shell
or carapace e.g. as in ostracods, bivalved molluscs |
| Antenna |
one of a pair of jointed feelers on head of various
arthropods |
| Antennule |
small antenna or feeler, especially the first pair
of antennae in Crustacea |
| Anterior |
towards the front, usually the head end (opposite to
posterior) |
| Appendage |
a limb or other process extending from the body,
usually articulated |
| Asymmetrical |
not symmetrical |
| Basal |
relating to, located at, or forming a base |
| Benthic |
living on the seabed |
| Bifid |
divided into two parts |
| Bilateral symmetry |
a basic body plan in which the left and right sides
of the organism can be divided into approximate mirror images of each other
along the midline |
| Bioluminescence |
production of light by living organisms, this
ability occurs in many different organisms, both plants and animals |
| Biramous |
in the Crustacea, it describes the condition in
which appendages are divided into two segmented branches: exopodite and
endopodite, these branches arise from a basal segment called the basipodite |
| Birefringent |
the resolution or splitting of a light wave into two
unequally reflected or transmitted waves by an optically anisotropic medium
such as calcite or quartz |
| Bisexual reproduction |
an animal that has the reproductive organs of both
sexes |
| Bract |
siphosomal element, usually containing much
mesoglea, with a protective or buoyancy function |
| Brood chamber |
a chamber used to incubate eggs, or young |
| Buoyant |
capable of keeping a body afloat |
| Calcareous |
of, containing, or like calcium carbonate |
| Calyptope |
planktonic larval stage following the nauplius in
euphausiid crustaceans |
| Carapace |
in the Crustacea it describes a fold of the
exoskeleton of the head that extends back over the thorax and may be fused
with a few or all of the thoracic segments. It may also extend laterally to
protect the sides of the body |
| Carnivore |
an animal that eats other animals |
| Carotenoid |
any of a group of red and yellow pigments |
| Globule |
a small spherical body |
| Caudal |
referring to the tail |
| Caudal rami |
literally, tail branches |
| Cephalosome |
first segment of the prosome (head and thorax of
copepods); bears mouthparts (crustaceans) |
| Cephalothorax |
fused head and thoracic body segments often covered
by a carapace dorsally and laterally (crustacean) |
| Chaeta |
bristles protruding from pockets in the body wall |
| Chelae |
the pincerlike organ or claw terminating certain
limbs of crustaceans |
| Chelate |
claw-like or pincer-like; bearing chela or claws |
| Cheliped |
either of the pair of appendages bearing a chela |
| Chitin |
a tough, protective, semitransparent substance,
forming the principal component of the exoskeleton |
| Chitinous |
composed of chitin |
| Cilia |
minute hairlike organelles, identical in structure
to flagella, which line the surfaces of certain cells and beat in rhythmic
waves, providing locomotion to ciliate protozoans and moving liquids along
internal epithelial tissue in animals |
| Ciliary |
relating to cilia projecting from the surface of a
cell |
| Cirri |
a filament or slender appendage serving as a foot,
tentacle, barbel, etc. |
| Coelenterate |
the animal phyla Cnidaria and Ctenophora
collectively |
| Coelenteron |
the single body cavity of a coelenterate |
| Coelom |
the body cavity of higher metazoans, between the
body wall and intestine, lined with a mesodermal epithelium |
| Compress |
to condense, shorten, or abbreviate |
| Compound eye |
the eye of most insects and some crustaceans, which
is composed of many light-sensitive elements, each having its own refractive
system and each forming a portion of an image |
| Coxa |
proximal segment of pereiopods of crustacea; may be
expanded and plate-like in some forms |
| Coxal plate |
coxae of pereiopods laterally expanded into
flattened lamellar structures extending freely (as plates) to overhang the
coxa-basis hinge of the leg |
| Cytoplasm |
the cell substance between the cell membrane and the
nucleus, containing the cytosol, organelles, cytoskeleton, and various
particles |
| Dactyl |
last (distal) segment of the endopodite of
crustacean appendages |
| Dactylozooid |
a kind of zooid of Siphonophora which has an
elongated or even vermiform body, with one tentacle, but no mouth |
| Denticle |
small tooth-like process |
| Detritivore |
an organism that feeds on and breaks down dead plant
or animal matter, returning essential nutrients to the ecosystem |
| Detritus |
dead material derived from biota |
| Diapause |
resting phase in the life history in which metabolic
activity is low, and periods of adverse environmental conditions can be
tolerated |
| Diel vertical migration |
refers to a pattern of movement that some organisms living in the ocean's photic zone undertake each day, travelling to the surface during the night to feed, then descending to darker, safer depths during the day |
| Dinoflagellate |
any of numerous chiefly marine plankton of the
phylum Dinoflagellata, usually having two flagella, one in a groove around the body
and the other extending from its centre |
| Diploblastic |
having two germ layers, the ectoderm and endoderm,
as in the embryos of sponges and coelenterates |
| Dorsal |
upper surface |
| Dorsoventral plane |
pertaining to the dorsal and ventral aspects of the
body; extending from the dorsal to the ventral side |
| Ectoderm |
the outer germ layer in the embryo of a metazoan |
| Endite |
extensions of some basal segments of the endopodite
of crustacean appendages that project medially (towards the midline of the
animal) |
| Endoderm |
the innermost body tissue that derives from this
layer, as the gut lining |
| Endopodite |
inner branch of a biramous crustacean appendage |
| Endopod |
the inner or medial branch of a two-branched
crustacean leg or appendage |
| Epibenthos |
organisms living on the surface of the seabed or in
the water column just above the bottom |
| Epidermis |
the outermost living layer of an animal, usually
composed of one or more layers of cells |
| Epipelagic |
of or pertaining to the stratum of the oceanic zone
where enough light is present for photosynthesis to occur |
| Epipodite |
extensions of some basal segments of crustacean
appendages that project towards the outside |
| Euphotic zone |
the uppermost layer of a body of water that receives
sufficient light for photosynthesis and the growth of phytoplankton |
| Exopodite |
outer branch of a biramous crustacean appendage |
| Exoskeleton |
a hard outer structure, such as the shell of an
insect or crustacean, that provides protection or support for an organism |
| Exumbrella |
convex surface of the bell of a medusa (jellyfish) |
| Filter feeders |
animals
that feed by straining suspended matter and food particles from water,
typically by passing the water over a specialized structure |
| Flagellum |
a long, lashlike appendage serving as an organ of
locomotion |
| Foliose |
with many leaves; having leaf-like lobes |
| Furcilia |
post-calyptope stage in the life cycle of euphausiid
crustaceans |
| Fuse |
to combine or unite |
| Gastrozooid |
feeding polyp, situated on the siphosome, bearing a
tentacle usually with several tentilla |
| Geniculate |
having kneelike joints or bends |
| Genital |
of, pertaining to, or noting reproduction |
| Gill |
the respiratory organ of most aquatic animals that
breathe water to obtain oxygen, consisting of a filamentous structure of
vascular membranes across which dissolved gases are exchanged |
| Gonad |
a sex gland in which gametes are produced; an ovary
or testis |
| Gonophore |
a structure bearing or consisting of a reproductive
organ or part, such as a reproductive polyp or bud in a hydroid colony |
| Gonozooid |
sexual stage of salps (planktonic tunicates) |
| Graze |
to feed |
| Gymnoplean tagmosis |
prosome-urosome boundary located posterior to fifth pedigerous somite |
| Herbivore |
an animal that mainly feeds on plants |
| Hermaphrodite |
an organism having both male and female reproductive
organs in a single individual |
| Heterotrophic |
capable of utilizing only organic materials as a
source of food |
| Holoplankton |
organisms that spend their entire life in the water
column, often called permanent plankton |
| Host |
a living animal or plant from which a parasite
obtains nutrition |
| Ischium |
first (proximal) segment of the endopod of
crustacean thoracic appendages |
| Lappets |
lobes of the bell margin of jellyfish (Scyphozoa)
medusae formed by scalloping |
| Larvae |
the young of any invertebrate animal |
| Lateral |
pertaining to, or on, the side |
| Locomotion |
the act or power of moving from place to place |
| Macrozooplankton |
zooplankters between 2 and 20 mm in length |
| Mandible |
a crushing or biting mouth appendage of a crustacean |
| Marsupium |
brood pouch found on the ventral surface of the
thorax of female peracarid crustaceans, formed from plate-like extensions of
the coxa of thoracic limbs (oostegites) |
| Manubrium |
tube bearing the mouth hanging down from the under
surface of a medusa |
| Maxilla |
paired mouthparts of crustaceans located anteriorly
to the mandibles |
| Maxilliped |
1, 2 or 3 pairs of thoracic appendages of
crustaceans adapted for assisting in feeding |
| Medusa |
a saucer-shaped or dome-shaped, free-swimming
jellyfish |
| Megazooplankton |
zooplankters greater than 20 mm in length |
| Membranous |
thin and flattened like a membrane |
| Meroplankton |
organisms that only spend part of their life cycle
in the water column e.g. eggs and larvae, often called temporary plankton |
| Merus |
second segment of the endopod of crustacean thoracic
appendages |
| Mesoglea |
the noncellular, gelatinous material between the
inner and outer body walls of a coelenterate |
| Mesopelagic |
of, pertaining to, or living in the ocean at a depth
of between 180 m (600 ft) and 900 m (3000 ft) |
| Mesozooplankton |
zooplankton between 200 µm and 2 mm in length |
| Metamorphic |
pertaining to or characterized by change of form, or
metamorphosis |
| Metamorphosis |
a profound change in form from one stage to the next
in the life history of an organism |
| Metanauplius |
a larval crustacean in a stage following the
nauplius, and having about seven pairs of appendages |
| Metasome |
thoracic segments in copepod crustaceans |
| Metatroph |
requiring dead organic matter for food |
| Microzooplankton |
zooplankton less than 200 µm in length |
| Moults |
periodic shedding of the cuticle |
| Natatory |
formed or adapted for swimming |
| Nauplii |
a larval form with three pairs of appendages and a
single median eye, occurring usually as the first stage of development after
leaving the egg |
| Nauplius |
early planktonic larval stage of crustaceans |
| Nectophore |
swimming bell |
| Nematocyst |
an organ in Cnidarians consisting of a minute
capsule containing an ejectable thread that causes a sting |
| Neritic |
living in coastal waters i.e. the shallow water over
the continental shelf |
| Neuston |
organisms that live at the very surface of the sea |
| Omnivore |
an omnivorous animal |
| Omnivorous |
eating both animal and plant foods |
| Ovigerous |
bearing eggs |
| Ovisac |
an egg-containing capsule |
| Paedomorphosis |
development of sexual maturity in an otherwise
juvenile body |
| Palp |
an elongated, often segmented appendage usually
found near the mouth in invertebrate organisms such as mollusks, crustaceans,
and insects, the functions of which include sensation, locomotion, and
feeding |
| Papillae |
one of certain small protuberances concerned with
the senses of touch, taste, and smell |
| Parapodia |
one of the unjointed rudimentary limbs or processes
of locomotion of many worms, as annelids |
| Parasite |
an organism that lives on or in an organism of
another species, known as the host, from the body of which it obtains
nutriment |
| Parasitic |
of, pertaining to, or characteristic of parasites |
| Parthenogenesis |
a form of reproduction in which the egg develops
into a new individual without fertilisation |
| Pedigerous |
bearing or having feet or legs |
| Pelagic |
living in the water column |
| Pereiopod |
walking leg (swimming leg of copepods); located
under the cephalothorax or metasome of crustaceans |
| Periphery |
the external boundary of any surface or area |
| Photophore |
light-producing organ |
| Photosynthetsis |
the process by which phytoplankton make
carbohydrates from carbon dioxide and water, using energy captured from
sunlight by chlorophyll, and releasing oxygen as a byproduct |
| Phytoplankton |
plankton consisting of free-floating algae,
protists, and cyanobacteria, phytoplankton form the beginning of the food
chain for aquatic animals and fix large amounts of carbon, which would
otherwise be released as carbon dioxide |
| Pigmentation |
coloration with or deposition of pigment (a coloring
matter or substance) |
| Pleopod |
swimming leg located under the abdomen or urosome of
crustaceans, often called swimmerets |
| Pleosome |
anterior 3 segments of pleon bearing biramous
pleopods |
| Pleura |
abdominal segments of crustaceans |
| Pleurobranchiae |
gills that arise from the lateral walls of the
thorax in decapod crustaceans |
| Pluteus |
larval stage of echinoid or ophiuroid echinoderms |
| Pneumatophores |
a gas-filled sac serving as a float in some colonial
marine hydrozoans, such as the Portuguese man-of-war |
| Podobranchiae |
gills that arise from the coxae of thoracic
appendages in euphausiid and decapod crustacean |
| Podoplean tagmosis |
prosome-urosome boundary located posterior to fourth pedigerous somite |
| Polyp |
a sedentary type of animal form characterized by a
more or less fixed base, columnar body, and free end with mouth and
tentacles, esp. as applied to coelenterates |
| Posterior |
towards the tail, behind; opposite to anterior |
| Propodus |
fourth (penultimate) segment of the endopodite of
the crustacean limb |
| Prosome |
anterior part of the body in some invertebrates |
| Prostomium |
anterior, pre-segmental region of the body, anterior
to mouth, may bear eyes, antennae and palps, and encloses part of the brain |
| Prototroch |
a preoral circlet of cilia of a trochophore larva |
| Protozoan |
any of a diverse group of eukaryotes, of the kingdom
Protista, that are primarily unicellular, existing singly or aggregating into
colonies, are usually nonphotosynthetic, and are often classified further
into phyla according to their capacity for and means of motility, as by
pseudopods, flagella, or cilia |
| Radially symmetrical |
animals which are symmetrical in 2 or more planes
e.g. a sea urchin |
| Rostrum |
prolongation of the anterior portion of the carapace
that projects beyond the head, usually between the eyes; found in Crustacea |
| Scavengers |
an animal or other organism that feeds on dead
organic matter |
| Scyphistoma |
a stage in the life cycle of a jellyfish or other
scyphozoan when it is fixed in place and reproduces asexually to produce
free-swimming medusae |
| Segmentation |
the subdivision of an organism or of an organ into
more or less equivalent parts |
| Segments |
a clearly differentiated subdivision of an organism
or part, such as a metamere |
| Sessile eye |
an eye attached by the base |
| Setae |
solid bristle-like structure found in Chaetognatha,
that are used for locomotion, in Arthropoda, hollow bristles containing
living tissue, which extend from appendages |
| Setose |
bearing bristles (setae) |
| Solitary |
living habitually alone or in pairs |
| Somite |
one member of a series of paired segments into which
the thickened dorsal zone of mesoderm is divided |
| Spawning |
to deposit eggs, produce spawn |
| Spine |
a stiff, pointed process or appendage on an animal |
| Stalked eye |
an eye attached to a stem or projection |
| Statocyst |
an organ found in many invertebrate animals that is
used to orientate the body in space i.e. for balance |
| Subchelate prehensile gnathopods |
the claw-bearing and grasping limbs of amphipods for
processing food |
| Subumbrella |
concave or undersurface of the bell of a medusa
(jellyfish) |
| Suspension feeders |
animals that feed by straining suspended matter and
food particles from water, typically by passing the water over a specialized
structure |
| Symbiotic |
the living together of two dissimilar organisms, as
in mutualism, commensalism, amensalism, or parasitism |
| Symbiotically |
the living together of two dissimilar organisms, as
in mutualism, commensalism, amensalism, or parasitism |
| Telson |
posterior projection of the terminal abdominal
segment of crustaceans, particularly malacostracans. Along with the uropods
it forms a tail fan |
| Tentacle |
any of various slender, flexible processes or
appendages in animals, esp. invertebrates, that serve as organs of touch,
prehension, etc.; feeler |
| Thermocline |
region of relatively sharp temperature change in the
water column, the depth of the thermocline varies seasonally in temperate
seas |
| Thoracic |
of, relating to, or situated in or near the thorax |
| Thorax |
the portion of the body between the head and the
abdomen |
| Tintinnid |
ciliates of the choreotrich taxon Tintinnida, distinguished by vase-shaped shells called loricae, which are
mostly protein but may incorporate minute pieces of minerals |
| Uniramous |
in arthropods, an unbranched appendage. In
crustaceans the exopodite is often lacking in walking legs |
| Uropod |
last of a pair of abdominal appendages in
malacostracan crustaceans, they are usually broad and flat and form a tail
fan with the telson |
| Urosome |
abdomen of copepods, though may be used for
abdominal segments bearing uropods in other crustaceans |
| Urosomal |
pertaining to the abdomen of copepods, though may be
used for abdominal segments bearing uropods in other crustaceans |
| Velum |
inward projection of the margin of the bell of
hydrozoan medusae |
| Ventral |
lower surface (opposite to dorsal) |
| Vertical migration |
refers to a pattern of movement that some organisms living in the ocean's photic zone undertake each day, travelling to the surface during the night to feed, then descending to darker, safer depths during the day |
| Zooid |
an organic cell or organized body that has
independent movement within a living organism, especially a motile gamete
such as a spermatozoon |
