| Abstract |
Burrowing by thalassinidean shrimp in modern tropical, shallow subtidal to intertidal carbonate environments is widespread and a powerful bioturbation agent of sandy substrates.Deep and intense burrowing by callianassid shrimp commonly occurs on the margins of hypersaline lagoons throughout the Bahamas, such as Pigeon Creek on San Salvador Island.Extensive sand flats along Pigeon Creek are deeply and thoroughly bioturbated by the callianassid Glypturus acanthochirus.In addition to dominating the deep tier, burrowing activity of the callianassids results in a highly mounded intertidal surface.Individual burrow cones commonly coalesce with time to form composite mound surfaces that become stabilized with development of microbial mats.These stabilized surfaces set the stage for colonization by shallow-tier burrowers, particularly the upogebiid shrimp, Upogebia vasquezi, and several species of fiddler crabs. Burrow systems of Upogebia vasquezi are distinctive and complex.They typically consist of a pair of U-shaped burrows in close proximity or crisscrossing, with knobs or short tunnels at their bases.The entirety of the burrow pair is surrounded by a thick, externally pelleted wall.Inside burrow diameters range from 2ð10 mm, and burrow depths are 10ð15 cm, in contrast to the much deeper callianassid burrows.These complex upogebiid burrows also occur as trace FOSSIL in late Pleistocene lagoonal facies on San Salvador.Initially reported as fragmentary burrow fills, whole burrow systems virtually identical to the modern upogebiid burrows more recently have been found at several localities.The fossil burrows are most abundant immediately below a terra rossa paleosol marking late Pleistocene stillstand and regression of seas associated with onset of Wisconsinan glaciation.This stratigraphic occurrence makes these complex upogebiid trace FOSSIL potentially useful as both paleoenvironmental and sea-level position indicators for Quaternary carbonate sequences throughout the Bahamas and other geologically similar regions. |
Curran, H.A. and A.J. Martin (2001) Intertidal mounds of tropical callianassids provide substrates for complex upogebiid shrimp burrows: modern and Pleistocene examples from the Bahamas. North American Paleontological Convention 2001, Paleontology in the New Millennium, Abstracts. 3817 pp. 