Dreissena polymorpha

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Dreissena polymorpha

• The infamous zebra mussel is native to rivers
  draining into the Caspian and Black seas.
  Individuals show a great variety of shapes and
  patterns, but all have a characteristically
  flattened ventral surface (left) and a gap for
  the byssal threads.

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Corbiculidae

• The Corbiculidae are a widespread family of
  moderate sized clams, often tinged or colored
  with violet on the interior. The name "corbicula"
  (little basket, from corbus, basket) refers to
  their characteristic concentrically ribbed shells
  and general shape. They are ovoviviparous,
  brooding internally fertilized eggs in brood
  pouches. Brood size is large, but the juveniles
  released into the surroundings are tiny, in
  contrast to the related sphaeriids. Individuals
  of Corbicula fluminea (Muller) are unusual in
  producing only eggs at earliest maturity,
  followed later by sperm. They then become
  simultaneously hermaphroditic and remain so
  throughout their lives (McMahon, 1991). There are
  twelve genera, including several characteristic
  of brackish waters (Banarescu, 1990).

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Sphaeriidae

• These are small nearly colorless clams of
  worldwide distribution. Members of the subfamily
  Sphaeriinae are referred to as fingernail clams,
  while the even smaller Pisidiinae are referred to
  as pea or pill clams. Species are distinguished
  on the basis of shell shape, presence and nature
  of striations, and details of hinge teeth
  structure. They inhabit ponds, swamps, and
  creeks.

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Lampsilis (Unioninae)

• Rayed pink fatmucket

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Epioblasma (Unioninae)

• "Snuffbox"Female on top, large male shell below.
  Members of thisgenus have been among the hardest
  hit by environmentaldegradation during the
  Twentieth Century. American interior.

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Quadrula

• Monkeyface

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Pleuroceridae

• Pleuroceridae Diverse in rivers of the Southeast
  United States. Many genera world wide. Several
  alternative classifications were considered by
  Banarescu (1990), who finally settled with the
  following subfamilies and genera

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Ancylidae (Limpets)

• Freshwater limpets are small to minute and, like
  freshwater mollusks in general, polyphyletic.
  While all are basomatophoran pulmonates, the
  limpet-like form appears to have arisen several
  times within that group.

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Planorbidae

• Generally referred to as "Wheel Snails", "Orb
  Snails", or "Ramshorn snails", the Planorbidae
  are the largest family of aquatic pulmonate
  gastropods, with species present on all
  continents and most islands. They are sinistral
  in their orientation, in spite of the fact that
  some may appear dextral due to the spire being
  sunken more than the umbilicus. Many of these
  species harbor the larvae of parasitic worms,
  particularly southern and Old-World taxa.
  Banarescu (1990) provides the following
  classification, here tabulated. Many subgeneric
  and subspecific names are in use, so for
  instance, the first specimens pictured are
  Planorbella (Pierosoma) trivolvis trivolvis (Say,
  1817).

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Physidae

• The Physidae, sinistral pond snails, are commonly
  referred to as tadpole snails or pouch snails.
  They are widespread, abundant, and tolerant of
  pollution. Burch (1982) indicates that they are
  most abundant in the New World. They have
  evidently found a shell morphology suitable for
  their life station, as he goes on to say "...the
  physids have undergone considerable
  diversification, much of which is not clearly
  exhibited in their shells. Many of the species
  and genera are not easy to identify on shell
  characters alone." Banarescu lists the following
  classification for the Physidae

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Lymnaeidae

• The Lymnaeidae are cosmopolitan, with members on
  all continents and large islands, and even some
  smaller oceanic islands. Most, in the subfamily
  Lymnaeinae, are dextral pond snails, while those
  in the subfamily Lancinae are limpet-like. Burch
  lists 57 species in nine genera for North
  America. In common with other freshwater
  pulmonates, all feed on algae and detritus, and
  all are hermaphroditic.