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Tracksites representing early human occupation are rare in South America. However, they have been reported in association with mammal and bird tracks from two coastal sites in Buenos Aires Province, Argentina. Both sites are reported in separate papers in this volume. In this paper a brief summary of the better known site is given on the basis of published information and the author's observations. [ABSTRACT FROM AUTHOR]

Large, complex burrows, informally referred to as stellate burrows, are present in eolianites of windward sea-cliff exposures facing Exuma Sound on Moriah Harbour Cay (Exumas, Bahamas). These cliffs consist of limestones (age <1,800 years before present) assigned to the Hanna Bay Member of the Rice Bay Formation and comprise three progradational lithofacies of foreshore, backshore, and dune deposits. Upper foreshore and backshore beds contain well-preserved specimens ofPsilonichnus upsilon, fossil burrows of the ghost crabOcypode quadrata. The overlying eolianites exhibit typical physical sedimentary structures characteristic of coastal dunes, with the most striking feature being the abundant presence of stellate burrows consisting of a central shaft (∼3 to 7 cm diameter) and numerous upward-directed branches (∼1 cm diameter) with smooth, unlined walls that form a radiate pattern in cross section. Parallel central shafts commonly join at the base, forming distinctive U-shaped structures that reach total heights of >1 m. Other examples exhibit an irregular arrangement of shafts that merge to form exceptionally large and architecturally complex structures. The result is a distinctive ichnofabric reaching levels of 3 or more on the Droser-Bottjer Ichnofabric Index scale. The presence of abundant stellate burrows can result in a significant increase in porosity and permeability within host eolianites. Previously, stellate burrows were assigned to the ichnogenusCellicalichnus, with origin attributed to burrowing and brooding activity of halictid (sweat) bees, common today in the Bahamas. Nonetheless, diagnostic cell structures are not present, and there are other important differences between stellate burrows and the previously described ichnospecies ofCellicalichnus. Other tracemaker possibilities are considered and evaluated, but firm identification of the tracemaker for the stellate burrows remains to be resolved. [ABSTRACT FROM AUTHOR]

The Hot Springs Mammoth Site, South Dakota, USA, has been excavated for over three decades, during which time numerous body fossils have been recorded. The site is particularly well known for the skeletal remains of mammalian megafauna. Bedding plane surfaces were studied that displayed the first record of small vertebrate (avian) and invertebrate traces. While large vertebrate tracks, often observed in cross-section, are well known at the site, the new traces form a hitherto unstudied assemblage. The presence of distinct didactyl and tridactyl avian tracks from the site are described here for the first time. The small (∼20 mm long) tracks and associated invertebrate traces suggest relatively high moisture content in the substrate on surfaces that experienced aerial or subaerial exposure. This is consistent with the interpretation that the upper layers of the site represent the latter stages of a sinkhole setting with a pond undergoing cyclical drying out. [ABSTRACT FROM AUTHOR]

Macaronichnus segregatis occurs in an upper foreshore conglomeratic to sandy beachrock dating from Roman times, on the east coast of Rhodes, Greece. In some laminae, M. segregatis is strongly oriented perpendicularly to the Recent and Holocene seashore. In other laminae, this trace fossil displays a winding to spiral course. These forms are introduced as new ichnosubspecies, M. segregatis lineiformis, M. segregatis maeandriformis and M. segregatis spiriformis, respectively. It is suggested that these middle-tier trace fossils were produced under conditions of different porewater flow. During higher energy periods, predominantly in winter, water movement perpendicular to the coastline caused M. segregatis to be oriented rheotactically. During periods of more or less stationary pore-water, predominantly in summer, M. segregatis assumed a spiral form. The winding form represents intermediate conditions. Closely beneath the Macaronichnus horizons a large burrow fill was found, probably referable to Psilonichnus isp. In the same beachrock are undertracks attributed to artiodactyls, associated with tracks and a trackway of human origin. The anatomy of the tracks indicates the direction of travel of the trackmakers, eastward and westward along-shore in all cases but one. The morphology of the tracks has been influenced by the gravitational effect of beach slope. Orientation, morphology and structure of trace fossils provide clear evidence that the sandstone and gravel unit is a beachrock and reveal the precise orientation of the paleoshoreline. [ABSTRACT FROM AUTHOR]

Hominid footprints are particularly appealing and evocative of the living activity of our ancestors. The most famous and oldest (Late Pliocene, ca. 3.7 Ma) hominid footprints, from Laetoli in East Africa, have been attributed, with some uncertainly, to genus Homo or Australopithecus. The African track record also yields Early Pleistocene (∼1.5 Ma) tracks attributable to Homo erectus. The only well-documented Middle Pleistocene tracks (age ∼325,000-385,000 yrs) are reported from Italy and presumably represent a pre-Homo sapiens species. The oldest Late Pleistocene tracks (∼117,000 yrs), from southern Africa, may represent modern humans. However, the majority of Late Pleistocene sites are European, associated with caves in Romania, Greece, France and elsewhere, where hominid track preservation is often of high quality. Dates range from ∼10,000 to ∼62,000 BP Cavesite mammal tracks are almost exclusively those of carnivores, thus representing a distinctive underground ecology. Late Pleistocene open air sites are reported from widely scattered locations in Africa, Turkey, Tibet, Korea, Australia and even in the New World (Chile, Argentina and Mexico). Early to Middle Holocene sites (> ∼4,000 yrs BP) mainly occupy riparian, lacustrine, estuarine and littoral settings where the ichnofaunas are dominated by ungulates and shorebirds. Among these sites from England, Nicaragua, Argentina and Mexico and the United States, a few have been described in some detail. Younger Holocene sites are frequently associated with specified cultural periods (e.g., Neolithic, Bronze Age) or specific indigenous cultures, where supplemental archeological evidence may be directly associated with the footprint evidence. At most surficial and some subterranean hominid tracksites, mammal and/or bird tracks are quite common and of use in creating a paleoecological picture of local faunas. The global distribution of human and hominid tracks is consistent with body fossil evidence and the record of archeological, cultural artifacts. However, in a few cases tracks suggest colonization of certain regions (Tibetan Plateau and the New World) earlier than previously thought. Tracks also give clues to behavior, age and health status of the trackmakers. [ABSTRACT FROM AUTHOR]

Bioerosion on shells of a brachiopod-bearing thanatocoenosis dredged on red-coral sea-bottom (depth 100 m, 12 miles off the southwestern coast of Alborán Island, Spain) was analyzed. Although low, the intensity of predation was noticeable. Predation drill holes belonging to the ichnogenera Oichnus simplex, O. paraboloides and O. ovalis were recognized. They were probably produced by Muricidae and Marginellidae (gastropods) and octopod cephalopods, respectively. Oichnus ovalis was more common on Terebratulina retusa . A strong selectivity with respect to species, valve, and size was noted. Terebratulina retusa , especially small individuals, was preyed upon more often than any other species. The central portion of both valves was attacked more frequently than expected by chance. [ABSTRACT FROM AUTHOR]