Gastropod shell repair in the intertidal of Bahيa la Choya (N. Gulf of California)

Models of evolutionary escalation between gastropods and their shell-breaking predators rely on the presence of a strong relation between predation intensity and repair frequency. Some previous work has suggested that both predation intensity and repair frequency have increased through geologic time. Repair frequency (the percentage of shells with at least one repair scar) in four Recent gastropods from the northern Gulf of California shows both high interspecific (7.6% in Cerithium stercusmuscarum to 87.9% in Turritella gonostoma) and interhabitat variation (11.9–30.7% in Theodoxus luteofasciatus and 26.8–64.9% in Cerithidea albonodosa). t-mixing, time-averaging and collecting practices might diminish variation in shell repair in fossil populations. Nevertheless, the high microhabitat variation observed here indicates that trends in shell repair through geologic time should consider the variation in shell repair at any one time. Reliable estimates of repair frequencies in fossil gastropods requires samples of several species and several habitats. Measuring shell repair should be better standardized, published data are now often difficult to compare.