Taken primarily from Kozloff, 1987, 1996 p.284 (Copyright 1987, 1996, University of Washington Press. Used in this web page by permission of University of Washington Press)
| Jump to: | ||||
| Lower taxonomic level | Main Page | Alphabetic Index | Systematic Index | Glossary |
Not in key: Parapholas
californica
| 1a | Rasping anterior portion of valves abruptly separated by a groove from the non-rasping portion (photo) | 2 |
| 1b | Rasping anterior portion of valves not abruptly separated from the non-rasping portion (burrowing in firm mud or clay; length to about 5 cm; not likely to be found north of southern Washington) | Barnea (Anchomasa) subtruncata |
| 2a | Without a myophore (apophysis) in either valve; posterior portion of shell, in mature specimens, tapering to a point, thus resembling a bird's beak; anterior portion of shell gaping as if abruptly cut off; siphonoplax (consisting of a pair of flaps that enclose the siphons) calcified | Netastoma rostrata |
| 2b | With a myophore (photo) in both valves; posterior portion of shell not tapering sufficiently to resemble a bird's beak (it may taper, however, especially in Pholadidea conradi); anterior portion of shell gaping (photo) (except in full-grown specimens, in which the gape is closed by a callum), but not appearing to have been abruptly cut off; siphonoplax not calcified | 3 |
| 3a | Rasping anterior portion of each valve occupying about half the area of the valve; valves without a shieldlike plate (protoplax) dorsal to the rasping portion; anteroventral gape not becoming closed, when the animal is full grown, by a callum; length up to 15 cm; burrowing in firm mud or clay | Zirfaea pilsbryi |
| 3b | Rasping portion of each valve occupying less than half the area of the valve (photo); valves with a thick, shieldlike plate (protoplax) dorsal to the rasping portion (photo); anteroventral gape (photo) becoming closed, in full-grown specimens, by a callum; length not exceeding 8 cm; generally boring in shale, sometimes in hard clay | 4 |
| 4a | Posterior (siphonal) ends of valves of mature specimens with a siphonoplax (this consists of a pair of flaps that enclose the siphons); siphons smooth | 5 |
| 4b | Posterior ends of valves of mature specimens without a siphonoplax; siphons smooth or slightly warty | 6 |
| 5a | Siphonoplax consisting of flexible flaps, not lined by calcareous granules; length to about 8 cm; generally boring in shale | Penitella penita |
| 5b | Siphonoplax not flexible, lined with calcareous granules; length to about 2.5 cm; generally boring in shells of abalones (Haliotis), Mytilus californianus, and other molluscs. | Penitella conradi |
| 6a | Siphons smooth; umbonal reflections (calcified plates between the protoplax and the rasping portion of each valve) tightly applied to the shell (Note: What was formerly called a protoplax on this species is now recognized as a dorsal extension of the callum--this species does not actually have a protoplax) | Penitella turnerae |
| 6b | Siphons warty; umbonal reflections free of the shell for about half their length (P. gabbi in original key) | Penitella richardsoni |
Parapholas californica
Penitella penita
Penitella turnerae
Zirfaea pilsbryi
