Plain Pocketbook
Lampsilis cardium
DIAGNOSTICS 3
SHELL
- size: large to very large; maximum 155 mm but males commonly over 130 mm; most under 120 mm
- thickness: moderately thick to 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 double loop bars, last ones more prominent; beak cavity moderately deep
- color/markings: tan to bright yellow, dark green rays thin to wide, numerous to completely absent, most specimens having just a few thin rays on posterior; periostracum occasionally iridescent in specimens from sandy or muddy habitats.
- 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 moderate, compressed/lamellar (more so in young and females), lightly protruding ventrally from hinge line.
- lateral teeth: well developed
- nacre: white, more rarely bright pink (such specimens have a coppery base color on the exterior surface)
Soft parts: foot white. mantle brindled yellow or rusty orange and black; inhalant and exhalent apertures short, wide/gaping, marbled, with contrasting pale papillae with darker interstitium. Papillae simple, bi or tri-forked; female lure: ): large, gaping "minnow-mimic", with long tail-like anterior fin-like extension, and well defined eye spot at posterior extremity; outer mantle plain gray or tan, more rarely marbled or blotched/spotted; inner lure mantle striped with lengthwise double contrasting lines; inactive/contracted lure in mature females readily apparent on marsupial margin on undisturbed individuals in situ; deployed/activated lure very large, and contractions/pulses are evenly rhythmic, continuous, and synchronous; luring activity is usually nocturnal, but can be diurnal in low-light situations.
Similar species/lookalikes: Largest specimens readily identifiable from size alone. Most easily confused with similarly large specimens of Actinonaias ligamentina where respective distributions overlap. Older shells of such specimens can look remarkably alike in respect to most of of their features, but can best be differentiated by the shallow beak cavities in A. ligamentina at any age, whereas beak cavities in L. cardium are contrastingly much deeper. Young live males can be confused with young and adult male Lampsilis siliquoidea or L. radiata. Young male Lampsilis radiata and L. siliquoidea are more compressed, and posterior margin more rounded above and below posterior end, compared to more angular in L. cardium. Base color in those two species also usually not as pale in young animals as is the case in L. cardium. Also very similiar to Lampsilis cariosa, to which it is closely related, but those two species' respective ranges do not overlap according to current data.
IMPORTANT NOTE: The taxonomy 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) ColinDJones, some rights reserved (CC BY-NC), uploaded by ColinDJones
- Adapted by Philippe Blais from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Lampsilis_cardium
