A LUNGFISH BURROW IN LATE CRETACEOUS UPPER CAPPING SANDSTONE MEMBER OF THE WAHWEAP FORMATION COCKSCOMB AREA, GRAND STAIRCASE-ESCALANTE NATIONAL MONUMENT, UTAH

Possible lungfish burrows have been reported from Triassic and Jurassic strata of the Colorado Plateau. Assignment of these burrows to the suspected burrow maker, a lungfish, has been problematic in these strata. Here we report on a probable lungfish burrow from the Late Cretaceous capping sandstone member of the Wahweap Formation in Grand Staircase-Escalante National Monument, Utah.

The burrow is composed of a vertical shaft with a widened bulb at the bottom. The apparent opening is 50 cm across with a neck diameter of 6 cm. The depth of the burrow is 31 cm with a bulb width of 11 cm. In lateral view the bulb displays an indentation approximately in the center. The infill shows apparent collapse into the burrow. These burrow measurements fall in the range of average modern lungfish - approximately 30 to 35 cm in depth, with a width of about 5 to 10 cm, and the bulbous bottom measuring roughly 17 cm. Modern lungfish burrow dimensions such as depths and diameters do vary depending on species, substrate and other environmental conditions, but aestivation burrows of lungfish usually attain lengths of 40 to 50 cm and widths of 5 to 15 cm. The indentation in the bulb is interpreted as a mark left by the turning lungfish. The sedimentologic setting is also consistent with a periodic wet – dry climate typical of lungfish.