Genetic relationships of several Amblemini species (Bivalvia : Unionidae) in Arkansas

Allozyme analysis of 16 loci was utilized to determine the genetic relation ships for four species of mussels in the Tribe Amblemini (Amblema plicata p licata (Say), Plectomerus dombeyanus (Valenciennes), Quadrula pustulosa pus tulosa (I. Lea), and Q. quadrula (Rafinesque)). Conspecific genetic distanc e was quite low between populations for each species, with ranges of 0.012- 0.113. The congeneric distance for Q. p. pustulosa and Q. quadrula was dete rmined to be 0.333. Distances between genera ranged from 0.396 to 0.787, si milar ranges to those of other unionid species studied. Genetic distance of Amblema and Plectomerus was greater than that expected based on previous s tudies, with Plectomerus more closely related to Quadrula than to Amblema.