Defining Characteristics and Taxonomic Divisions
Either a lophophore or trochophore larva, but mostly united by
Colonial filter feeders; coelomate zooids have retractable lophophores surrounding the mouth (not anus); secrete a non-living outer coat.
Cup-shaped, blastocoelomate zooids that filter feed using lophophores surrounding both the
all are sedentary, but either individual or colonial
Acoelomate and living exclusively on the mouthparts of marine lobsters in the northern hemisphere; adhesive disk used to attach and a modified lophophore surrounding the mouth (but not the anus) for feeding on lobster scraps.
that bear lophophores surrounding the mouth but with the anus on the outside of it, lophophores have hollow, cilia-lined tentacles with only one cilium per cell.
Body enclosed by dorsal and ventral shells, may be attached to a pedicle.
Brachiopods in which shells are
Brachiopods in which shells
held together by a hinge
Worm-like, tube-secreting brachiozoans that are not enclosed within shells
Trochozoans with trochophore larvae
Small and wormlike with 20-30 ciliated cells arranged in two distinct layers with reduced mesoderm between; parasites of marine inverts
Coelomate and unsegmented eutrochozoans with a mantle, radula, muscular foot, pectinate (comb-like) gills called
Small (1-5cm) and worm like mollusks with a mantle containing calcareous spicules but lacking a shell; found in deep, marine environments
Lack a continuous shell and instead have 8 dorsal plates covering a broad and creeping foot
~20 species of small (<3cm) marine mollusks with a single, cap-like shell and many ctenidia
Snails and snail-like mollusks with prominent head, and most with a single, coiled shell carried over a muscular foot that is modified for crawling;
experience torsion during development
Shelled, primarily marine gastropods with anterior mantle cavity containing ctenidia and an operculum that covers the shell opening when the animal retracts inside
Marine gastropods with reduced or absent shell and partial detorsion. Mantle cavity lacking, or posterior and reduced
Primarily terrestrial or freshwater gastropods. Ctenidia lacking and mantle cavity modified as a lung
Burrowing marine mollusks with a single, elongate, tubular, and slightly curved shell that is open on both ends.
Actively swimming, elongated marine mollusks; cephalization is extensive with a specialized nervous system and foot modified into tentacles and a funnel for food capture and locomotion, respectively; mouth is in a buccal mass surrounded by powerful, parrot beak-like jaws.