Marine Sci Taxonomy

Crustacea (Most marine arthropods)

Malacostraca

Largest class; includes crabs, lobsters, and shrimp; have a hard exoskeleton, jointed appendages, and two pairs of antennae

Homarus americanus (American Lobster), Panulirus argus (Caribbean Spiny Lobster), Cancer pagurus (Edible Crab)

Maxillopoda

Small crustaceans, often planktonic or parasitic; includes barnacles and copepods

Balanus (Acorn Barnacle), Calanus (Copepod)

Branchiopoda

Mostly freshwater, but some are marine; use leaf-like appendages for swimming

Artemia salina (Brine Shrimp)

Chelicerata (Fewer marine species)

Merostomata

Ancient marine arthropods; have a horseshoe-shaped carapace and book gills

Limulus polyphemus (Atlantic Horseshoe Crab)

Pycnogonida (Sea Spiders)

Long, thin legs, reduced body, feed using a proboscis

Nymphon species (Sea Spider)

Gastropoda (Snails, Slugs, Limpets)

Torsion (twisting of body during development); may have coiled shells

Cone Snail (Conus), Sea Slug (Nudibranch), Limpet (Patella)

Bivalvia (Clams, Oysters, Mussels, Scallops)

Two hinged shells; filter feeders with no radula

Blue Mussel (Mytilus), Eastern Oyster (Crassostrea virginica), Giant Clam (Tridacna)

Cephalopoda (Squids, Octopuses, Cuttlefish, Nautiluses)

Highly intelligent, tentacles with suckers, jet propulsion for movement

Giant Squid (Architeuthis), Octopus (Octopus vulgaris), Cuttlefish (Sepia)

Polyplacophora (Chitons)

Oval body with eight armored plates; cling to rocks in intertidal zones

Common Chiton (Katharina tunicata)

Scaphopoda (Tusk Shells)

Tubular, tusk-shaped shell; live buried in sand

Dentalium species

Monoplacophora (Primitive Mollusks)

Cap-like shell; deep-sea, segmented body structure

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Class Asteroidea (Sea Stars)

Five or more arms with tube feet for movement; can regenerate limbs

Common Starfish (Asterias rubens), Crown-of-Thorns Starfish (Acanthaster planci)

Class Ophiuroidea (Brittle Stars & Basket Stars)

Slender, flexible arms distinct from the central disc; move by arm wriggling instead of tube feet

Brittle Star (Ophiothrix fragilis), Basket Star (Gorgonocephalus)

Class Echinoidea (Sea Urchins & Sand Dollars)

Round or flattened bodies covered in spines; use Aristotle’s lantern (jaw structure) to feed

Purple Sea Urchin (Strongylocentrotus purpuratus), Sand Dollar (Clypeaster subdepressus)

Class Holothuroidea (Sea Cucumbers)

Soft, elongated body; can eviscerate (expel internal organs) as a defense mechanism

California Sea Cucumber (Parastichopus californicus), Tiger Tail Sea Cucumber (Holothuria thomasi)

Class Crinoidea (Feather Stars & Sea Lilies)

Suspension feeders with feathery arms for filtering plankton; ancient lineage of echinoderms

Feather Star (Antedon species), Sea L

Subphylum

Class

Distinct Characteristics

Examples

Urochordata (Tunicates & Sea Squirts)

Ascidiacea (Sea Squirts)

Sessile, sac-like filter feeders, lose notochord in adulthood

Ciona intestinalis (Sea Squirt)

Thaliacea (Salps)

Free-floating, barrel-shaped, gelatinous body, colonial or solitary

Salpa maxima (Giant Salp)

Appendicularia (Larvaceans)

Retain notochord as adults, build mucus “houses” for feeding

Oikopleura species

Cephalochordata (Lancelets)

Leptocardii (Lancelets)

Small, fish-like, burrowing filter feeders, retain notochord throughout life

Branchiostoma lanceolatum (Lancelet)

Vertebrata (Marine Vertebrates)

Agnatha (Jawless Fish)

No jaws, paired fins, or scales; cartilaginous skeleton

Myxine glutinosa (Hagfish), Petromyzon marinus (Sea Lamprey)

Chondrichthyes (Cartilaginous Fish)

Skeleton of cartilage, paired fins, gill slits, no swim bladder

Carcharodon carcharias (Great White Shark), Manta birostris (Manta Ray)

Osteichthyes (Bony Fish)

Skeleton of bone, operculum-covered gills, swim bladder

Thunnus (Tuna), Hippocampus (Seahorse)

Reptilia (Marine Reptiles)

Cold-blooded, scaly skin, air-breathing, lay eggs on land (except sea snakes)

Chelonia mydas (Green Sea Turtle), Hydrophis platurus (Yellow-Bellied Sea Snake)

Mammalia (Marine Mammals)

Warm-blooded, air-breathing, have hair and mammary glands, live birth

Balaenoptera musculus (Blue Whale), Tursiops truncatus (Bottlenose Dolphin), Trichechus manatus (Manatee)