The Burgess Shale Anomalocaridid Hurdia and Its Significance for Early Euarthropod Evolution
Allison C. Daley,1*
Graham E. Budd,1
Jean-Bernard Caron,2
Gregory D. Edgecombe,3
Desmond Collins4
As the largest predators of the Cambrian seas, the anomalocaridids
had an important impact in structuring the first complex marine
animal communities, but many aspects of anomalocaridid morphology,
diversity, ecology, and affinity remain unclear owing to a paucity
of specimens. Here we describe the anomalocaridid
Hurdia, based
on several hundred specimens from the Burgess Shale in Canada.
Hurdia possesses a general body architecture similar to those
of
Anomalocaris and
Laggania, including the presence of exceptionally
well-preserved gills, but differs from those anomalocaridids
by possessing a prominent anterior carapace structure. These
features amplify and clarify the diversity of known anomalocaridid
morphology and provide insight into the origins of important
arthropod features, such as the head shield and respiratory
exites.
2 Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto M5S 2C6, Canada.
3 Department of Palaeontology, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
4 437 Roncesvalles Avenue, Toronto M6R 3B9, Canada.
* To whom correspondence should be addressed. E-mail: allison.daley{at}geo.uu.se
