On the natural history and functional morphology of the clam shrimp, Lynceus brachyurus Müller (Branchiopoda: Laevicaudata)

Abstract

The small bivalved clam shrimp, Lynceus brachyurus Muller, 1776, is seasonally abundant in two long-duration vernal pools in central Ohio, USA. Previously unrecognized anatomical features include dorsal patches of spines or filaments on posterior trunk segments, diverse medial spines on the dorsal lobes of the leg exopods, two-segmented dorso-lateral appendages on the male eleventh segment, and brown coloration on portions of male legs. It can swim actively, but is basically benthic. Females are sometimes totally quiescent. Gut contents, observation, and experiments showed a diet of substrate scrapings, suspended detritus, and small zooplankton. Females ovulate following male stimulation and produce new egg batches without an intervening molt. Repeated matings are needed to produce the large egg masses often carried. Larvae were first collected in late February, and adults in late April. Lynceus was found in nine of the eleven years studied, being absent in the years that followed two years of high rainfall.