DRILLING PREDATION ON SCAPHOPODS FROM THE LOWER PINECREST BEDS OF THE TAMIAMI FORMATION IN SARASOTA COUNTY, FLORIDA

Fossil scaphopods have remained understudied, and only a few reports of predation on those mollusks exist. This study examines several genera (i.e, Anatalis, Cadulus, Graptacme, Tesseracme) of scaphopods collected from the lower Pinecrest beds (Petuch Units 4-9) of the Tamiami Formation (upper Pliocene), from Phase 10 of SMR Aggregates, Inc. in Sarasota, Florida. Three 3-gallon bulk samples were collected in the field, serial-screen washed in the lab, and then picked for scaphopod remains. These specimens were then evaluated in terms of completeness, fragmentation patterns, drilling predation, size and location of drill holes, presence of repair scars, and shell abrasion. Measurements of length, width, and posterior and anterior opening shape and size were also recorded. Comparisons of lengths and widths of the broken specimens and complete specimens were used to determine which portion of a complete shell is represented by a given broken specimen. Relative drill hole location was used to assess if there was a preferred site of attack or if it was random. Preliminary results indicate that 54.8% of specimens show moderate to heavy shell abrasion, 38.7% of the specimens bear repair scars, and 19.4% of the specimens have been drilled. Although these results are preliminary, the percentage of drilling is significantly higher than found in most previous studies of scaphopods.