ALBERT

Description: The ability of paleobiologists to draw paleoecological inferences based on spatial faunal variability within a single stratigraphic interval depends ultimately on the spatial resolving power of the fossil record. This paper evaluates the potential spatial resolution of fossil assemblages by examining modern skeletal remains of molluscs on a benthic transect, along which there is a marked decrease in seagrass cover, in Smuggler's Cove, St. Croix, U.S. Virgin Islands. The sampling transect began in a Thalassia-covered area approximately three meters deep, extended into slightly deeper water with lighter seagrass cover, and ended on an open, bioturbated sandy tract at a depth of nearly six meters.Two-way cluster analysis and polar ordination of 37 samples of molluscan remains, taken at 10-meter intervals along the 360-meter transect, reveal patterns of variation that are shown by correlation analyses and consideration of the autecologies of individual species to be related to measured changes in vegetation. There is a transition from dominance primarily by epifaunal gastropods living on seagrass blades to dominance by infaunal, burrowing bivalves as grass cover becomes lighter. Some non-systematic variability exists in faunal distributional patterns within areas where the environment does not vary systematically, but this does not mask the regular faunal transitions related to environmental changes. Correspondence between the dead and live faunas is difficult to ascertain because of the scarcity of live fauna in collected samples.The results suggest that spatial faunal transitions in fossil remains at even the fine scale evaluated in this study are potentially preservable in the fossil record.

Description: The global diversification of the class Bivalvia has historically received two conflicting interpretations. One is that a major upturn in diversification was associated with, and a consequence of, the Late Permian mass extinction. The other is that mass extinctions have had little influence and that bivalves have experienced slow but nearly steady exponential diversification through most of their history, unaffected by interactions with other clades. We find that the most likely explanation lies between these two interpretations. Through most of the Phanerozoic, the diversity of bivalves did indeed exhibit slow growth, which was not substantially altered by mass extinctions. However, the presence of “hyperexponential bursts” in diversification during the initial Ordovician radiation and following the Late Permian and Late Cretaceous mass extinctions suggests a more complex history in which a higher characteristic diversification rate was dampened through most of the Phanerozoic. The observed pattern can be accounted for with a two-phase coupled (i.e., interactive) logistic model, where one phase is treated as the “bivalves” and the other phase is treated as a hypothetical group of clades with which the “bivalves” might have interacted. Results of this analysis suggest that interactions with other taxa have substantially affected bivalve global diversity through the Phanerozoic.

Description: Trace fossils and fish remains, representing three species described by Greiner from the Devonian of New Brunswick, have been transferred and reposited in the New Brunswick Museum. Holotype, paratype, and figured specimens originally at the University of New Brunswick are now located in the Palaeontology Type Collection of the New Brunswick Museum (NBMG). All specimens have been assigned new catalogue numbers.

Description: Specimens of a new species of the Permian waagenophyllid coral genus Waagenophyllum, W. klamathensis, have been recovered from limestone lenses near the top of the Upper Permian Dekkas Formation in the eastern Klamath Mountains, and similar specimens have been collected from an isolated limestone mass in the eastern Hayfork terrane of the southwestern Klamath Mountains, northern California. Another specimen of Waagenophyllum, which may represent another species, has been recovered from another limestone mass in the Hayfork terrane. These specimens of Waagenophyllum, a genus which otherwise is restricted to the Tethyan Province, provide the only tie between the Permian limestone masses of the eastern Hayfork terrane, which also contain typical Tethyan foraminifers, and the eastern Klamath Mountains terrane (McCloud belt), which contains many fossils with non-Tethyan affinities.

Description: A sinkhole locality in the Wasatch Plateau has yielded Utah's first record of the American mastodon. At nearly 3,000 m this fossil-bearing site denotes the highest elevation yet reported for Mammut americanum, and demonstrates that mountainous terrain was not a barrier to dispersals. A presumably preferred habitat of spruce-fir open forests, similar to that in the area today, was present during the time of the mastodons reported here. Two incomplete individuals of M. americanum are the only fossils that were found in the sinkhole. Entrapment appears to have been the cause of death. Since the record of M. americanum in western North America is sparse, the present find has added significance in providing more information about the nature of this animal. A possible association of a recovered spear point fragment near the fossils indicates the possibility that man and mastodon were contemporaneous here. Three independent datings were run on mastodon bone. Two based on carbon-14 yielded dates of 7,090 ± 200 yr B.P. and 7,590 ± 100 yr B.P., while the third, using the racemization process, indicated an age of less than 10,000 yr B.P.

Description: Jujuyaspis borealis is reported from earliest Ordovician (North American usage) limestones in central Texas and western Utah, the first time this species has been recognized in the United States. Jujuyaspis is a widespread olenid trilobite that occurs near the base of the Tremadoc Series in a variety of lithologies in North and South America, Europe, and Asia. When international agreement is reached on the exact horizon at or near the base of the Tremadoc Series that is to be used as the Cambrian–Ordovician boundary, Jujuyaspis will likely prove to be a very useful taxon for recognition of the boundary interval.

Description: North American pantodonts have mostly been recovered from the Rocky Mountain states. However, none has previously been accurately reported from Utah. Reference to Coryphodon was made by Cope in 1872 under the name Bathmodon, to which others (e.g., Marsh, 1876) later referred, but this probably was in error. The reported material apparently came from southwestern Wyoming rather than northeastern Utah. An undescribed coryphodontid jaw, though, has been collected from Eocene deposits in the Uinta Basin.