New Mexico Geological Society Annual Spring Meeting — Abstracts

The Kinney Brick quarry, NMMNH locality 345, in the Manzanita Mountains of central New Mexico is a Lagerstätte that yields a diverse fossil invertebrate, vertebrate and plant biota. The New Mexico Museum of Natural History and Science (NMMNH) has conducted systematic collecting over a 25 year period at the site and has comprehensively sampled all fossils, including coprolites. There are about 30 cataloged Kinney coprolite lots in the NMMNH collection that were first described in 1992. In general, the coprolites are laterally compressed and occur in finely laminated shale.

There are six principal morphologies of coprolites in the Kinney sample. Two specimens are ovoid and consist primarily of conchostracan valves with very little groundmass. About seven specimens are large, thin ovoids (up to 60 mm long) that occur on bedding planes and have little groundmass and much fish debris – similar specimens have elsewhere been described as regurgitalites. Modern sharks occasionally regurgitate material, but there is no clear evidence that such behavior can be demonstrated for fossil fish. Most putative regurgitalites are most parsimoniously interpreted as: (1) disarticulated fish; (2) decomposed coprolites; or (3) coprolites with little groundmass.

About 10 Kinney specimens represent ovoid coprolites of medium size (up to 40 mm long), which are very compact. One morphology of large (70 mm long), elongate coprolite has more three-dimensionality than other forms and is 20 mm thick. Six specimens represent a small, compact, circular-to-ovoid coprolite with a longest dimension of 10-20 mm. Three specimens represent small, linear, ribbon-like coprolites less than 11 mm long. The Kinney coprofauna differs from other Pennsylvanian localities in New Mexico in lacking distinct, spiraled morphologies. The Kinney Quarry yields a large fish fauna. The absence or paucity of spiral coprolites is reflective of the relative scarcity of chondrichthyans and sarcopterygians at Kinney. The conchostracanrich coprolites may have been produced by acanthodians. The majority of ovoid coprolites at Kinney probably represent palaeonisciforms.