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There are few body fossil biotas known from early Paleozoic accretionary shorelines, and very few examples of Ordovician soft-bodied assemblages. This study documents two recently discovered biotas from separate sedimentary basins in Manitoba, Canada, that provide unique information about tropical shoreline communities shortly before the Late Ordovician extinction event. Each site represents a distinct depositional environment, but they share biotic elements, including eurypterids, xiphosurids, and large problematic tubes. The William Lake biota, representing more restricted conditions, includes jellyfi sh that are among the best hydromedusan body fossils known. Rocks at the Airport Cove site, deposited under more open circulation, contain scolecodonts and noncalcifi ed algae. These biotas have some parallels with the recently described Middle Ordovician Winneshiek Lagerstätte, but are also similar to some Late Silurian assemblages. Considered together, early Paleozoic marginal marine deposits are a rich but as yet poorly known source of paleobiodiversity data.

One hundred and twenty-five linguliformean brachiopods of late Marjuman (Cambrian) age with shell perforations, presumably caused by predation, were recovered from shallowwater limestones at two localities of the Deadwood Formation in the Black Hills of South Dakota, USA. Three-quarters of the perforated valves belonged to taxa in the order Acrotretida, while one-quarter of the specimens belonged to those of the order Lingulida. This is the first report of predation of fossil lingulids. In both orders there was a marked selection for valve type. Ninety-five per cent of all perforations of acrotretids were in the ventral valve, while 87% of all perforations of lingulids were in the dorsal valve. The highest rate of predation of collected acrotretids, at any stratigraphic horizon, was 22%, while the rate of predation of collected lingulids, at any given stratigraphic horizon, was as high as 9%. Half of the perforated valves had round holes with a sharp, non-beveled exterior edge, and half had irregularly shaped holes with chipped interior edges. The former type is attributed to either boring or a swift, piercing percussive strike, while the latter is attributed to a smashing percussive strike with a blunt appendage. A third type of perforation consisting of minute, roughly circular holes is thought to be too small to be the work of predators, and is assumed to be the result of an encrusting organism or parasite. The different types of perforation seen in the brachiopod valves indicate that there was more than one type of predator attacking them, including possibly one of the earliest durophages. Various hypothetical predators are suggested as potential candidates for causing the shell perforations. The criteria for their selection as possible linguliformean predators include possessing the ability to produce one of the two types of shell perforation, and being small enough to warrant preying on small (< 2 mm) brachiopods. ᮀ Brachiopoda, Cambrian, Deadwood Formation, Linguliformea, Marjuman, predation, South Dakota. Sean P. Robson [sdrobson@mts.net], The

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Six species of conulariids, assigned to four genera, were recovered from the type locality of the Cat Head Member of the Red River Formation in southern Manitoba, Canada. These are middle Katian (Late Ordovician) in age. The most abundant conulariid species from this locality, Conularia porcella, is new, and is represented by 21 specimens. Additionally, 28 three-dimensionally preserved micromorphic conulariids, assigned to Eoconularia aff. loculata, were recovered using acetic acid preparation from limestone samples of late Katian (Late Ordovician) age. These samples had been collected from Churchill, northern Manitoba, by the Geological Survey of Canada's J. B. Tyrrell in 1894. These taxa are unusually abundant for conulariids, which are normally represented by only a few specimens from any given locality, and this abundance may be a reflection of the exceptional preservation at these two localities.