Journal of Paleontology; September 2006; v. 80; no. 5;
p. 811-825; DOI: 10.1666/0022-3360(2006)80[811:ECMEEA]2.0.CO;2
© 2006 Paleontological Society
EARLY CAMBRIAN METAZOAN EGGS, EMBRYOS, AND PHOSPHATIC MICROFOSSILS FROM NORTHWESTERN CANADA
LEANNE J. PYLE1,
GUY M. NARBONNE2,
GODFREY S. NOWLAN3,
SHUHAI XIAO4 and
NOEL P. JAMES2
1 Geological Survey of Canada, 9860 West Saanich Road, Sidney, British Columbia V8L 4B2, <lpyle{at}nrcan.gc.ca>,
2 Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario K7L 3N6, <narbonne{at}geol.queensu.ca>, <james{at}geol.queensu.ca>,
3 Geological Survey of Canada, 3303-33rd St. NW, Calgary, Alberta T2L 2A7, <gnowlan{at}nrcan.gc.ca>,
4 Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg 24061, <xiao{at}vt.edu>
Three-dimensionally phosphatized, spherical fossils, interpreted as metazoan eggs and embryos on the basis of taphonomic features and cleavage patterns, are reported for the first time from the Cambrian of North America. These microfossils occur with a phosphatized biota of skeletonized fossils, including specimens indicative of the earliest Cambrian AnabaritesProtohertzina Zone in the Wernecke Mountains of eastern Yukon Territory, northwestern Canada. They range in size from 0.25 mm to more than 1.0 mm in diameter and can be referred to two genera, Olivooides Qian, 1977 and Archaeooides Qian, 1977. The North American discovery extends the biogeographic range of earliest Cambrian eggs and embryos from coeval successions in China and Siberia, suggesting a wide geographic distribution of these taxa, and emphasizes the crucial role of local environmental and taphonomic conditions in preserving this phosphatic window into the record of early animal evolution. In addition to previously reported taxa, the phosphatized biota also include indeterminate spheroids, fused clusters of Protohertzina siciformis Missarzhevsky, 1973, the enigmatic rodlike fossil Zhejiangorhabdion comptum Yue and Zhao, 1993, phosphatized fossils, including Paradoxiconus typicalis Qian et al., 2001, protoconularid Carinachites sp., and phosphatic tubes assigned to Hyolithellus cf. H. isiticus Missarzhevsky, 1969, cf. Pseudorthotheca sp., and ?Rugatotheca sp.
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