The World's First Clam Shrimp Symposium: Drawing Paleontology and Biology Together.

After a symposium and special issue devoted to the study of clam shrimp, it is tempting to ask what is next...

The Fossil Record of the Clam Shrimp (Crustacea; Branchiopoda).

Clam shrimp (the paraphyletic assemblage of spinicaudatans, laevicaudatans, cyclestherids and the extinct leaiins) are small, bivalved branchiopod crustaceans that specialize in ephemeral freshwater habitats. They have a long fossil record (Devonian onward) that has often been overlooked. Here we briefly review the fossil record of the major groups of clam shrimp and clear up some misconceptions in the literature as to their origin.

Fossil and Modern Clam Shrimp (Branchiopoda: Spinicaudata, Laevicaudata): The World's First Clam Shrimp Symposium and a Celebration of Brian V. Timms.

This special volume of Zoological Studies is the result of a symposium entitled "Fossil and Modern Clam Shrimp" held at the midyear meeting of The Crustacean Society in May of 2019. This symposium is the first ever focusing on clam shrimp, and the first conference where both palaeontologists and biologists specialising in these animals were able to come together. The papers presented here provide insight into the palaeontology, biology, ecology, taxonomy and phylogeny of the clam shrimp.

Testing the phylogenetic position of Cambrian pancrustacean larval fossils by coding ontogenetic stages.

The study of ontogeny as an integral part of understanding the pattern of evolution dates back over 200 years, but only recently have ontogenetic data been explicitly incorporated into phylogenetic analyses. Pancrustaceans undergo radical ontogenetic changes. The spectacular upper Cambrian "Orsten" fauna preserves phosphatized fossil larvae, including putative crown-group pancrustaceans with amazingly complete developmental sequences.

Decoupling elongation and segmentation: notch involvement in anostracan crustacean segmentation.

Repeated body segments are a key feature of arthropods. The formation of body segments occurs via distinct developmental pathways within different arthropod clades. Although some species form their segments simultaneously without any accompanying measurable growth, most arthropods add segments sequentially from the posterior of the growing embryo or larva.

Controls on gut phosphatisation: the trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah).

Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods--typically the most diverse fossilised organisms in Cambrian ecosystems--where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology.