Yellow Lampmussel
Lampsilis cariosa
DIAGNOSTICS 3
SHELL
- size: mid-sized to large; maximum 140 mm, but most under 100 mm
- thickness: thin to moderately thick
- shape: oval, with a rounded ventral edge; posterior ridge sharpest nearer beaks; posterior end more pointed, angular in males
- width: inflated to very inflated, even in very young
- surface: smooth
- beaks: inflated, well elevated above hinge line; sculptures: 5-6 weakly double looped or single looped bars, last ones more prominent; beak cavity moderately deep
- color/markings: plain bright yellow or yellowish-orange to tan or light brown; thin green rays occasional on posterior end.
- sexual dimorphism: usually obvious: posterior usually pointed at end of posterior ridge in males while squared or rounded in females. Adult males grow larger than females; females more inflated than males.
- pseudocardinal teeth: small to moderately developed, compressed to lamellate (more so in young and females), lightly protruding ventrally from hinge line and close to beaks, situated under or in close proximity to them anteriorly; hinge line is often slightly curved, dipped in front of beaks
- lateral teeth: well developed, narrow and high towards posterior.
- nacre: white, occasionally pinkish or orangish around beak cavities
SOFT PARTS: foot white; female lure: "minnow-mimic", with tail-like anterior fin-like extension, and well defined eye spot at posterior extremity
Similar species/lookalikes: Most similar to L. cardium, to which it is closely related, but these two taxa have widely disjunct distributions *. Base color and raying in L. cardium is much more variable. Also very similar to the sympatric species Leptodea ochracea within its range in Canada. L. ochracea shares the same general shape and size, but has a straighter hinge line, and nacre is more commonly pinkish, especially in anterior half. L. ochracea is also more commonly finely rayed on most of the shell, and pseudocardinals are thinner/lamellate, but more importantly positioned well in front of the beak, a feature that is probably the most useful in differentiating the two species. Lastly, L. ochracea sometimes has a short wing in front of beaks.
*IMPORTANT NOTE: The taxonomy and respective distributions of L. cardium and L. cariosa could possibly be reassessed according to future genetic studies, therefore their respective morphological identification criteria are currently not definitive.
Sources and Credits
- (c) Philippe Blais, some rights reserved (CC BY-NC-ND), uploaded by Philippe Blais
- (c) Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology, some rights reserved (CC BY-NC-SA), https://collections.nmnh.si.edu/services/media.php?env=iz&irn=80108
- Adapted by Philippe Blais from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Lampsilis_cariosa
