TN00452 BIRDWING PEARLY MUSSEL LEMOIX RIMOSUS
Physical description: This species is seldom over 50 mm in in length, 40 mm height, and 25 mm in width. The valves are generally solid, slighltly inflated and subtriangular to subovate in outline. The posterior ridge is well developed, somewhat rounded. The shell surface is marked by strong, irregular growth lines, with the posterior 1/2 to 2/3 marked by strong, corrugated, subradial sculpture. The outer covering of shell is generally dark green to black (older specimens) with faint rays often present on the younger individuals. They aer sexually dimorphic with females being smaller, more ovate, and usually inflated due to marsupial swelling along the posterior ventral margins *4270*. Reproduction: This species is sexually dimorphic. The male releases sperm into water currents, female fertilized eggs inside gill cavity through siphoning. The bradytictic species breeds from midsummer through fall or early winter, embryos develop in female over winter and are released the following spring or summer *4270*. Glochidia are of the hookless type, and have a delicate shell with valves shaped like a bowl of a very blunt spoon *4270*. Behavior: This species is sedentary and disperses during the larval stage only by the movement of the host species *2100*. Limiting factors: This species is limited by siltation, pollution, and impound ments which are the major causes for their decline *4270*. Origin: The origin of this species is native *4270*. It is presently known only from large tributaries of the Tennessee River including the Duck, Clinch, Elk, and Powell Rivers. They have also been transplanted to sites on the Duck, Buffalo, Nolichucky, and North Fork Rivers *JRK1*. Population parameters: The longevity of this species is 50 plus years *4270*. Aquatic/terrestrial associations: This is a glochidia parasite on Notropis galacturus, Notropis spilopterus and Etheostoma zonale *4270*. TN00452PHYSICAL DESCRIPTION: SMALL SHELL IS SUBTRIANGULAR TO SUBOVATE IN OUTLINE, VALVES ARE VERY SOLID AND SLIGHTLY INFLATED, BEAKS ARE HIGH AND TURNED FORWARD, BEAK SCULPTURE CONSISTS OF 3 OR 4 DISTINCT DOUBLE LOOPED BARS, FIRST 1 OR 2 BARS ARE SUBCONCENTRIC, POSTERIOR RIDGE IS WELL-DEVELOPED, BEING SOMEWHAT ROUNDED, AND DISTINCT, SURFACE OF SHELL IS MARKED BY STRONG, IRREGULAR GROWTH LINES, POSTERIOR HALF OR TWO- THIRDS OF THE SHELL IS MARKED BY A STRONG, CORRUGATED (RIMOSE), SUBRADIAL SCULPTURE, EPIDERMIS IS DULL GREEN OR YELLOWISH-GREEN AND FEEBLY RAYED, BECOMING DARKER WITH AGE, LEFT VALVE HAS 2 LOW RUGGED PSEUDOCARDINAL TEETH SEPARATED FROM THE 2 SHORT HEAVY AND SLIGHTLY CURVED LATERAL TEETH BY A BROAD INTERDENTUM, RIGHT VALVE HAS 1 TO 3 PSEUDOCARDINAL TEETH, WITH THE MAIN TOOTH RAGGED AND TRIANGULAR, MOST SPECIMENS HAVE A SINGULAR LATERAL TOOTH, ALTHOUGH SOME DEVELOP A VESTIGIAL TOOTH BELOW, MUSCLE SCARS ARE SMALL AND IMPRESSED, PALLIAL LINE IS IMPRESSED AND DISTINCT THROUGHOUT, BEAK CAVITY IS VERY SHALLOW OR WANTING, NACRE IS WHITE AND IRIDESCENT POSTERIORLY, SHELLS THICKEST ANTERIORLY, VALVES OF MALE POSSESS A BROAD SHALLOW RADIAL DEPRESSION IN FRONT OF POSTERIOR RIDGE, FEMALE SHELL USUALLY OVATE, SMALLER THAN THE MALE, AND IS SOMETIMES INFLATED WITH A WEAKLY DEVELOPED MARSUPIAL SWELLING ALONG THE POSTERIOR VENTRAL MARGIN *TN5587* REPRODUCTION: SPECIES APPEARS BRADYTICTIC, AS GRAVID SPECIMENS HAVE BEEN COLLECTED IN MID- SEPTEMBER *TN5587* OTHER: GLOCHIDEA ARE SUBOVATE, BEING HIGHER THAN LONG *TN5592*
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References for Life History Codes
2100, 4270, 4270
Comments on Life History Codes