Pink Heelsplitter

Potamilus alatus

Diagnostics 7

SHELL

  • size: large to very large, maximum 180 mm, but most under 110 mm
  • thickness: thin
  • shape: quadrate with pronounced dorsal wing on posterior slope, especially evident in juveniles. once adult size has been reached, this wing often abruptly levels off with additional growth, giving it a truncated look in older animals.
  • width: compressed
  • surface: rough, especially in siphon area. pronounced growth rings. two low but distinct posterior ridges, usually highlithed by dark lines.
  • beaks: flat, barely above hinge line. sculptures: 3-4 weak narrow bars.
  • color/markings: uniform pale to dark brown, getting darker with advanced age
  • sexual dimorphism: subtle. females more rounded in marsupial area.
  • pseudocardinal teeth: small but well defined, conical
  • lateral teeth: present
  • nacre: entirely pink to purplish throughout in most individuals. more rarely bluish-white with a reduced pale link flush around hinge line.

Soft parts: foot white

Similar species/lookalikes: usually very distinctive when alive or as fresh shells. Weathered shells can become much paler, lose all of their nacre color, and thus resemble weathered Leptodea fragilis, as older L. fragilis, live or dead, can darken quite a bit. Nacre color not always reliable on its own to distinguish from that taxon as some animals will only have a very similar light pink flush around the hinge area, in L. fragilis fashion. small yet well defined conical pseudocardinal teeth clearly projecting from the hinge line then differentiate P. alatus from the latter's rudimentary, compressed, lamellar pseudocardinals that project little. Combination of prominent dorsal wing and entirely purple nacre is diagnostic of the taxon in Canada for most specimens.

Sources and Credits

  1. (c) Philippe Blais, some rights reserved (CC BY-NC-ND), https://www.inaturalist.org/photos/9839335
  2. (c) redgarter, some rights reserved (CC BY-NC-ND), uploaded by Philippe Blais, https://www.inaturalist.org/photos/12865753
  3. (c) redgarter, some rights reserved (CC BY-NC-ND), uploaded by Philippe Blais, https://www.inaturalist.org/photos/12865702
  4. (c) redgarter, some rights reserved (CC BY-NC-ND), uploaded by Philippe Blais, https://www.inaturalist.org/photos/12865703
  5. (c) redgarter, some rights reserved (CC BY-NC-ND), uploaded by Philippe Blais, https://www.inaturalist.org/photos/12865704
  6. (c) redgarter, some rights reserved (CC BY-NC-ND), uploaded by Philippe Blais, https://www.inaturalist.org/photos/12865700
  7. Adapted by Philippe Blais from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Potamilus_alatus

More Info

iNatCA Map