Mucket

Actinonaias ligamentina

DIAGNOSTICS 13

SHELL

  • size: large to very large
  • thickness: thick to very thick
  • shape: elliptical to oval, with bluntly pointed posterior common, more so when young
  • width: moderately compressed to moderately inflated
  • surface: smooth but disk irregularities common (pockmarks and dents)
  • beaks: extend well above hinge line; sculptures: few, faint double loop ridges, often obscured; beak cavity shallow
  • color/markings: yellowish-brown ,tan to dark brown; vaguely defined green rays, from broad and prominent to entirely absent
  • sexual dimorphism: none
  • pseudocardinal teeth: moderately heavy, not projecting much into cavity
  • lateral teeth: strong, thick
  • nacre: white, occasionally pinkish

Soft parts: foot white

Similar species/lookalikes: live adults most likely to be confused with compact specimens of male Plain Pocketbook, Lampsilis cardium, or even very large and compact male fatmuckets, Lampsilis siliquoidea. both those two last taxons are usually much more elongate than the mucket, but older adults can sometimes be of very similar shape. a helpful distinguishing feature is the posterior ridge that is usually much more curved downwards, much closer and aligned with the posterior slope's margin in the mucket, whereas it is much straighter in the other two, with a wider posterior slope. In live juveniles this feature can be much more subtle, and similarities with young male L. siliquoidea can then become quite confusing. beak sculptures are distinctive in young L. siliquoidea when still well defined, and young L. cardium are usually very different, with their more inflated beaks. mature shells are noticeably thicker than in either Lampsilis species, but in young shells this feature is much less obvious. nacre and teeth are quite similar in all three species. Muckets rarely have very fine contrasting rays as is commonly seen in L. cardium or L. silliquoidea; beak cavity is significantly shallower in mucket compared to Lampsilis cardium: the entirety of its apex can still be viewed at a significant angle away from the inter-valve plane, whereas in L. cardium it begins to be obscured from barely above it. This last criteria seems to be the most reliable to discern it from this most similar lookalike at any size.

DISTRIBUTION/WATERSHEDS 13

ONTARIO:

  • Maitland R.
  • Sydenham R.
  • Thames R.
  • Grand R.

Sources and Credits

  1. (c) Philippe Blais, some rights reserved (CC BY-NC-ND), https://www.inaturalist.org/photos/56896050
  2. (c) Philippe Blais, some rights reserved (CC BY-NC-ND), https://www.inaturalist.org/photos/56896067
  3. (c) Philippe Blais, some rights reserved (CC BY-NC-ND), https://www.inaturalist.org/photos/56896070
  4. (c) Philippe Blais, some rights reserved (CC BY-NC-ND), https://www.inaturalist.org/photos/56896359
  5. (c) Will Van Hemessen, some rights reserved (CC BY-NC-ND), uploaded by Philippe Blais, https://www.inaturalist.org/photos/13169169
  6. (c) Philippe Blais, some rights reserved (CC BY-NC-ND), https://www.inaturalist.org/photos/43952148
  7. (c) Philippe Blais, some rights reserved (CC BY-NC-ND), https://www.inaturalist.org/photos/43952159
  8. (c) Philippe Blais, some rights reserved (CC BY-NC-ND), https://www.inaturalist.org/photos/43952173
  9. (c) Will Van Hemessen, some rights reserved (CC BY-NC-ND), uploaded by Philippe Blais, https://www.inaturalist.org/photos/13169109
  10. (c) Owen Strickland, some rights reserved (CC BY-NC), https://www.inaturalist.org/photos/48927908
  11. (c) Owen Strickland, some rights reserved (CC BY-NC), https://www.inaturalist.org/photos/48927899
  12. (c) Scott Gibson, some rights reserved (CC BY-NC), https://www.inaturalist.org/photos/10071851
  13. (c) Philippe Blais, some rights reserved (CC BY-SA)

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