The shallow-marine gastropod (snail) family Aporrhaidae [pronounced "a-poor-rye-id-dee"] has a geologic range of Triassic (210 million years ago) to modern day. During the Jurassic and Cretaceous, this family diversified greatly, but the mass-extinction event at the end of the Late Cretaceous (66 million years ago) greatly decimated the family. There are only a few Cenozoic genera and only a few remaining species in the world today.
The most characteristic shell feature of aporrhaids is the expanded outer lip with its labral digitations or "wing-like" structure present on the lower half or so of the shell and originating from the right side of the aperture (the opening where the snail extends its body, when it crawls about). The shape of a "wing" is very important in the identification of the various genera and species, but finding specimens with the "wing" intact is not common. Juvenile aporrhaid shells (those without a "wing") tend to have similar looking shells. Naming of new species, therefore, requires having mature specimens available.
Aporrhais pespelecani (Linnaeus, 1758), which lives today in waters extending from Norway, the British Isles, and into the Mediterranean Sea, is one of the most common extant (living) aporrhaids. The species name, pespelecani, is based on this gastropod having a forked "wing," shaped like a pelican's webbed foot. The following two pictures are of the same specimen of this species.
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| Two views, front and back, of a specimen of Aporrhais pespelecani (Linnaeus). The specimen is 42 mm in height and 31.5 mm in width. |
Aporrhais serresianus (Michaud, 1828) is another apporaid that lives in the Mediterranean Sea. This species is uncommon and is found in relatively deep water. The following two pictures are of a specimen of this species.
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Two views, front and back, of a specimen of A. pesgallinae. The specimen
is 33.8 mm in height and 31.8 mm in width.
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