Abstract

An assemblage of four Carbonita species was deposited with charophytes, lungfishes and lysorophids in a lenticular mudstone from a Cisuralian freshwater pond deposit from the lowest Permian. Samples contained few adult Carbonita, indicating perhaps a stressed and unstable environment. Two species new to science, C. ovata n. sp. and C. triangulata n. sp., occur together with C. evelinae and C. pungens. Morphological characters of these Carbonita suggest an affinity with the Healdioidea, marine taxa that are probably ancestral to the Carbonitidae. The muscle-scar patterns of Carbonitidae, which comprise closely grouped circular bundles of secondary muscle scars, resemble closely those of Healdioidea and not those of Cypridoidea and Cytheroidea, whose muscle scars are fewer and spaced further apart. The muscle-scar pattern of C. pungens, described here for the first time, is a circular scar with an ascertainable pattern of secondary scars. C. pungens and species of Darwinula are morphologically similar, but study of additional specimens of C. pungens with better-preserved muscle scars is essential to determine their evolutionary affinity.

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