Paper No. 191-15
Presentation Time: 2:30 PM-6:30 PM
OPENING AN OLD CAN OF (TUBE)WORMS: REEVALUATING WYATTIA TAYLOR 1966 FROM THE EDIACARAN OF SOUTHWESTERN LAURENTIA AND CONICAL FOSSILS FROM THE CAMBRIAN OF MISSOURI
Ediacaran strata from the Death Valley, White Inyo, and Sonoran regions have yielded a variety of small, lightly mineralized, tubular to conical fossils that are relevant to understanding early metazoan history. Two examples that merit reinvestigation are Wyattia Taylor 1966, known from the Reed Dolomite of California, and Nevadatubulus Signor et al. 1987, from the Deep Spring Formation of California and Nevada. Since their initial designations, there are few described occurrences of Wyattia and Nevadatubulus, and most are met with the question of whether they might be better aligned within the genus Cloudina. For example, Grant (1990) synonymized Nevadatubulus (along with Sinotubulites, another tubular fossil) from Nevada with Cloudina, but only at the genus-level. Wyattia is typically preserved in coarsely crystalline dolopackstones and was thus originally described from observation of weathered hand samples, polished slabs, and petrographic thin sections. In contrast, Nevadatubulus occurs in fine-grained limestone packstones (coquinas), and was originally described from fossils extracted via targeted acid etching. In the case of the latter, at least, the description of Nevadatubulus was hindered by poor preservation quality; such preservational challenges also exist with Wyattia due to pervasive dissolution and recrystallization. With recent emphasis on employing cloudinomorphic fossils to develop stage-level subdivisions of the Ediacaran Period, it is becoming increasingly important to evaluate geographically restricted taxa to resolve any potential congeneric placement with other reported terminal Ediacaran taxa. With this in mind, we reanalyzed Wyattia, including topotype specimens, using a suite of techniques including X-ray tomographic-, scanning electron-, and petrographic microscopy. Our aim is to provide a complete reevaluation of this taxon, and specifically its potential relationship to (or, perhaps within) the genus Cloudina, with improved imaging methods. To groundtruth this approach, we employ the same techniques to evaluate little-known occurrences of conical fossils obscurely noted as Wyattia, though we tentatively reinterpret them as Salterella, from the Cambrian (Series 3) Bonneterre and Davis formations of Missouri.