The Exotics Guide

Ruditapes philippinarum Image 6

A dense clam bed consisting mainly of Venerupis philippinarum, in a saltmarsh channel on the east shore of San Francisco Bay.

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Ruditapes philippinarum Image 5-siphons

Venerupis philippinarum showing siphons (at top of image) and foot (at lower left). The head end is toward the bottom of the image. Note that the siphons are fused along most of their length, but separated at the tips.

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Ruditapes philippinarum Image 4-interior

Venerupis philippinarum from San Francisco Bay showing the interior of the shell, with the head end toward the right. The margins and hind end are deep purple. The rounded, yellow-stained indentation extending in from the hind end marks the pouch that holds the retracted siphons when the shell is closed. There are no teeth along the margin of the shell (compare to Protothaca, below).

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Ruditapes philippinarum Image 3-from black mud

Venerupis philippinarum taken from black, anoxic mud underneath rocks in San Francisco Bay. The head end is toward the right.

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Ruditapes philippinarum Image 2 & Key Image-from SFBay#2

Venerupis philippinarum from San Francisco Bay, showing a common color pattern of dark triangular markings. The head end is toward the right.

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Ruditapes philippinarum Image 1-from SFBay

Venerupis philippinarum from San Francisco Bay. The head end is toward the right. Note the oval shape, strong radiating ridges, and umbo angled toward the head end.

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Venerupis philippinarum Adams & Reeve, 1850

JAPANESE LITTLENECK CLAM, JAPANESE COCKLE, MANILA CLAM

  • Kingdom: Animalia
  • Phylum: Mollusca
  • Class: Bivalvia
  • Subclass: Heterodonta
  • Order: Veneroida
  • Superfamily: Veneroidea
  • Family: Veneridae

Venerupis philippinarum has a thick shell, oval in outline, with a maximum length of about 6 cm. The surface of the shell is sculpted with weak concentric ridges that mark the shell's progressive growth, and more pronounced straight ridges that radiate outward from the center of growth to the shell margins. The umbo—the hump at the center of growth—is at the hinged margin of the shell, about 1/3 of the shell's length away from the head end and angled toward it.

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6

Corbula amurensis from San Francisco Bay. with a young barnacle (Balanus improvisus) attached to the hind part of the shell (lower right part of image).

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5

A Corbula amurensis shell, showing the overbite.

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Corbula Key Image

Dried shells of Corbula amurensis from San Francisco Bay. Note the “overbite” of the larger valve that shows clearly in the clam at the center right.

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