Trilobite Clusters: What do they tell us? A preliminary investigation

Clusters or aggregations of fully and/or partially articulated trilobite exoskeletons have fascinated palaeontologists and fossil collectors for well over a hundred years. Professional palaeontologists have been interested in their implications for trilobite palaeobiology (e.g., behaviour), whilst collectors have admired them for their aesthetic qualities (Johnson, 1985). Studies on trilobite clusters began over a century ago, with some of the earliest papers by Walcott (1875, 1881) and Beecher (1894). However, it was the pioneering work of S.E. Speyer (1985, 1987, 1990, 1991; Speyer and Brett, 1985) on Middle Devonian trilobite clusters from New York that brought trilobite behavioural palaeobiology to the fore. Since this time, there have been only a limited number of case studies on the interpretation of trilobite clusters (see Paterson et al., 2007 and references therein).