Short notes and reviews Phosphatocopine arthropods

For anyone interested in the early history and evolution of arthropods, one simply cannot get along without reference to the series of works that have been appearing since the 1970s by Dieter Waloszek and Klaus Müller on the Cambrian Orsten fossils. Of particular importance in this regard is the sequence of exceptional monographs published in Fossils and Strata. This volume is the most recent in that series. The Phosphatocopina were first recognized by Müller (1964) and placed among the ostracodes. With little more than the bivalved shell known at that time, this was understandable. Any small bivalved critters found in the Cambrian were automatically considered to be ostracodes in those days. In this instance, the phosphatocopines were believed to be related to another non-descript Cambrian group, the Bradoriina. It was only with the discovery of the Swedish “stink stones,” or Orsten, that people began to discover the animals inside the bivalved shells. Other localities came to light, and even the internal anatomy of bradoriines revealed itself. Subsequently, Müller and Walossek (1991) came to doubt the ostracode affinities of phosphatocopines, and this began a reassessment of all the tiny Cambrian bivalved arthropods. It became evident that the only thing all these animals shared in common was a bivalved shell. The animals inside were all different from each other. Presently, there is even doubt in some circles as to whether the Ostracoda form a monophyletic group. The whole Cambrian radiation of crustaceomorph forms is now being reassessed. Needless to say, understanding the phophatocopines is proving to be critical towards understanding the phylogenetic relationships among the earliest crustaceomorph arthropods.