TN00050 CAMEL SHELL DROMEDARY MUSSEL DROMUS DROMAS
Physical description: This is a medium-sized shell rounded to subtriangular; generally yellow-green with 2 sets of broken green rays, narrow rays of dots or broken lines, nacre ranges from white to salmon or reddish in shell has hump with row of small knobs near mid-line extending from umbo area to ventral margin. The glochidia are bean-shaped and of the hookless type *4271*. Reproduction: The males discharge sperm into the water column which is taken in by females during siphoning. Fertilization of the eggs occurs in the gills of the female and the fertilized eggs develop to maturity (glochidia) there. Fertilization occurs in mid-summer and fall and the fully developed glochidia are released into the water column the following spring and summer and they attach to the gills and fins of host fish in order to metamorphose into juvenile mussels. The juveniles then drop off the fish to begin life independently *4271*. Behavior: This species is sedentary but may move with water depth fluctuations. The juveniles are dispersed by host fish *4271*. Origin: The origin of this species is native *4271*. It is presently known only from the Tennessee, Cumberland, Clinch, and Powell Rivers *4271*. Limiting factors: The host fish is necessary for the completion of the repro- ductive cycle *4271*. They may prefer acidic water with a low flow *4271*. Impoundments, siltation, and pollution are speculated as major causes for decline *4271*. Population parameters: The longevity of this species is 50 or more years *4271*. Aquatic/terrestrial associations: They serve as food for muskrats, and the shells are occasionally found in middens *4271*. PHYSICAL DESCRIPTION: SHELL MEDIUM, ROUNDED IN OUTLINE WITH FULL HIGH BEAKS SET WELL FORWARD, VALVES SOLID, SOMEWHAT INEQUILATERAL AND INFLATED, BEAK STRUCTURE CONSISTS OF FINE RIDGES RUNNING PARALLEL WITH THE GROWTH LINES WITH THE FURROWS INTERRUPTED AT POSTERIOR RIDGE, SURFACE MARKED BY IRREGULAR CONCENTRIC GROWTH LINES WITH A DECIDED STRONG CONCENTRIC RIDGE AT THE POINT OF EARLIER GROWTH, FORMING AN IRREGULAR KNOB ON THE MEDIAN LINE OF THE SHELL, POSTERIOR DORSAL AND VENTRAL MARGINS ROUNDED, ANTERIOR MARGIN SOMEWHAT PROJECTED AND ROUNDED, PERIOSTRACUM SHINY TAWNY OR YELLOWISH-GREEN WITH TWO SETS OF BROKEN GREEN RAYS, ARE SEVERAL CONTIGUOUS NARROW RAYS OF DOTS OR BROKEN LINES ALTERNATING WITH WIDE RAYS OF IRREGULAR BLOTCHES AND FLECKS OF GREEN, LEFT VALVE HAS TWO LOW, ROUGH PSEUDOCARDINALS, POSTERIOR-DORSAL ONE BEING LARGER, TWO STRAIGHT, RELATIVELY SHORT LATERAL TEETH, SEPARATED FROM PSEUDOCARDINALS BY A BROAD FLAT INTERDENTUM, RIGHT VALVE HAS THREE PSEUDOCARDINALS, THE MIDDLE ONE BEING MUCH LARGER, LATERAL TOOTH SINGULAR, THOUGH SOME MAY DEVELOP A VESTIGIAL LOWER TOOTH, BEAK CAVITIES DEEP AND COMPRESSED, MUSCLE SCARS SMALL AND IMPRESSED WITH ANTERIOR ADDUCTOR MUSCLE SCAR, TYPICALLY HAVING A ROUGH SURFACE, DISTINCT PALLIAL LINE ANTERIORLY, BECOMING FAINT POSTERIORLY, NACRE WHITE, BUFF, OR SALMON *TN5587* REPRODUCTION: MARSUPIUM CONSISTS OF NUMEROUS OVISACS ALONG THE LARGER POSTERIOR SECTION OF THE OUTER GILL, GRAVID FEMALES HAVE BEEN OBSERVED DURING SEPTEMBER, GLOCHIDEA ARE MUCH LONGER THAN HIGH AND HAVE NO HOOKS *TN5587*
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References for Life History Codes
4271, TN5587
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