Also known as Ichthyosaur graveyard

Where: Ultima Esperanza, Chile (51.1° S, 73.3° W: paleocoordinates 50.7° S, 34.1° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Zapata Formation, Valanginian to Valanginian (139.8 - 129.4 Ma)

• group of beds-level stratigraphic resolution

Environment/lithology: deep-water; siltstone and claystone

Size class: macrofossils

• 46 articulated ichthyosaur skeletons

Preservation: soft parts, replaced with pyrite

Collection methods: quarrying, mechanical

• Ichthyosaur remains are mostly exposed in polished sections due to the

•glacier abrasion but are principally preserved in three dimensions. Due to the exceedingly hard matrix, an extraction was extremely difficult and only achieved for five specimens. Therefore, most data were collected in the field. The outlines of bones exposed on the surface were traced 1:1 on transparent foil. The data set comprises field number, GPS value, biometric

•data, the directions of skull and belly, and taphonomic or anatomic specialties if present. In addition, photos were taken of each specimen, especially of diagnostic body areas, i.e., fins and skull. For extraction we used a high-performance diamond disc mounted on a fuel-driven rock cutter, and complemented the extraction with a pneumatic hammer drill, placing lines of bore holes under the specimens and then removing the sediment between them with hammer and chisel. Mechanical preparation with air abrasive and hand tools was initiated at the laboratory of Heidelberg University, Germany, but was impossible due to the exceedingly hard sediment and relatively soft bone. Chemical preparation of these specimens with acetic acid was not possible due to paucity of carbonate in the matrix.

Primary reference: W. Stinnesbeck, E. Frey, L. Rivas, J. P. Pérez, M. L. Cartes, C. S. Soto, and P. Z. Lobos. 2014. A Lower Cretaceous ichthyosaur graveyard in deep marine slope channel deposits at Torres del Paine National Park, southern Chile. Geological Society of America Bulletin [P. Mannion/J. Tennant]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 164882: authorized by Philip Mannion, entered by Jonathan Tennant on 29.12.2014

Creative Commons license: CC BY (attribution)