Abstract Volume

This is the first mammalian fauna known from northern Funding Sources ANR program DEADENDER (ANR- Idaho as previously known Cenozoic faunas from the 18-CE02-0003-01) – P.I. M. J. Orliac. region are the early to late Blancan faunas, from the Glenn’s Ferry Fm., SW Idaho, some 570 miles to the south Mesozoic & Early Cenozoic Mammalian Evolution and the early to mid-Blancan faunas from the Ringold Fm., central Washington, 225 miles away. A NEW SPECIES OF PLEUROSTYLODON (MAMMALIA, NOTOUNGULATA) FROM THE Mesozoic & Early Cenozoic Mammalian Evolution LATE LOS QUEÑES LOCALITY, ANDEAN MAIN RANGE, CENTRAL CHILE CAINOTHERIIDAE FROM QUERCY (SW OF FRANCE): DIVERSITY DYNAMICS AND Wheat, Theodore C.1, McGrath, Andrew J.1, Croft, Darin BIOTIC/ABIOTIC INTERACTIONS AROUND THE A.2, Wyss, André1, Flynn, John J.3 EOCENE–OLIGOCENE TRANSITION (34–33.5 MA) 1Department of Earth Science, University of California, Santa Barbara, Santa Barbara, California, U.S.A., Weppe, Romain1, Condamine, Fabien1, Blondel, Cécile2, 2Department of Anatomy, Case Western Reserve Guinot, Guillaume1, Orliac, Maëva J.1 University, Cleveland, Ohio, U.S.A., 3Division of 1Institut des sciences de l’évolution (ISE-M), Montpellier, Paleontology and Richard Gilder Graduate School, Occitanie, France, 2PALEVOPRIM, Poitiers, Nouvelle American Museum of Natural History, New York, New Aquitaine, France York, U.S.A.

Understanding the diversity dynamics of species is a Notoungulata, the most diverse group of ungulates present central topic in evolutionary biology and paleontology. during South America’s Cenozoic isolation, is classically After the massive extinction of the –Tertiary subdivided into Toxodontia and Typotheria. Here we crisis, the Eocene–Oligocene transition (34–33.5 Ma) describe a new species of Pleurostylodon (a toxodontian) coincided with one of the major extinction events of the based on a left hemimandible bearing a complete dentition. Cenozoic. It is indeed associated with major climatic, ‘Isotemnidae,’ to which Pleurostylodon has long been geographical, and ocean circulation changes. At the same assigned, is currently considered a non-monophyletic time, a major faunal turnover occurred in Europe, known assemblage of basal toxodontians. Pleurostylodon was first as the ‘Grande Coupure’. This event is associated with the identified from the Casamayoran South American Land extinction of numerous endemic European placental Age (SALMA) of Argentine Patagonia (now , which had evolved in the ‘island Europe’ including both Vacan and Barrancan 'subages'); other context from the middle to the upper Eocene. European isotemnids became known subsequently from the artiodactyls are particularly impacted by these changes, Casamayoran and Mustersan SALMAs of Patagonia and and many endemic families died out around this transition. the Casamayoran of northwest Argentina. This discovery However, a family of small artiodactyls, the likely extends the range of Pleurostylodon into the Cainotheriidae, crossed the Eocene–Oligocene boundary Mustersan SALMA of central Chile. and diversified during the Oligocene. Here we applied, for The type and only specimen of this new taxon, SGOPV the first time, a well-known biological model of diversity 5529, includes a complete left lower tooth row, including analysis to a group of extinct artiodactyls, the i1–i3, the lower canine, p1–p4, and m1–m3. SGOPV 5529 Cainotheriidae. Using the cainotheriid fossil record from bears, at mid-crown height, a small projection on the the karstic infillings of the Quercy Phosphorites (south- posterior face of the metaconids of m1–m3 that, with wear, western France), we observe that this family experienced a merges with the metaconid forming the 'curved' metalophid major radiation phase during the early Oligocene, followed seen in some species of Pleurostylodon and differing from by a decline phase until the end of the Oligocene. The other isotemnids. SGOPV 5529 is distinct from other exceptional fossil record of the Quercy phosphorites species of Pleurostylodon in being more hypsodont and provides us with an extremely precise vision of the lacking cingulids on p3–m3. Incorporating the new taxon evolution of Cainotheriidae diversity over 10 million years, from Chile into a previously published genus-level on both sides of the Grande Coupure, with incomparable phylogenetic analysis pairs SGOPV 5529 with preservation indices. Our results also highlight the absence Pleurostylodon. of direct correlation between the speciation and extinction SGOPV 5529 was recovered from the Abanico Formation phases and the important environmental changes of the near the town of Los Queñes in the Andean Main Range of Eocene–Oligocene transition and the end of the Oligocene. central Chile. This area records at least two These results thus suggest the potentially important role of stratigraphically superposed SALMAs. The strata from biotic interactions in the evolutionary success and then which SGOPV 5529 was recovered are likely late Eocene decline of the Cainotheriidae from Quercy. in age and assignable to the Mustersan SALMA. This Abstract Volume

discovery thus extends the biochron of Pleurostylodon, and DNE values for entire tooth rows are moderately to which was previously restricted to the Casamayoran highly successful at distinguishing among all four dietary SALMA. In addition to Pleurostylodon n. sp., the late categories; herbivores and omnivores have the highest Eocene strata at Los Queñes host a diverse, as yet values. However, this pattern becomes somewhat muddled undescribed mammalian fauna. Future reports on other when those values are averaged along tooth rows. PCV elements of this fauna promise to shed light on the seems to be independent of OPCR and DNE, exhibiting an biogeographical relationships between Patagonia and inverse pattern, but there is more overlap between northwest Argentina for the middle to late Eocene. categories. The number of teeth also appears to have a Funding Sources NASA NAG5-11354; NSF DEB- greater impact on PCV results; specimens with more teeth 0513476 and DEB-0317014; and the AMNH Frick Fund. have lower PCV values. This is the first time that any of these three-dimensional dental topography metrics have Colbert Poster Prize/Cenozoic Herpetology ever been applied to squamates, paving the way for future work, including dietary reconstructions of extinct fossil LIZARD BYTES: THREE-DIMENSIONAL DENTAL squamates. TOPOGRAPHY ANALYSIS OF EXTANT Funding Sources Thesis Travel Grant, University of PLEURODONT SQUAMATES, WITH Minnesota; Joyce Davenport Fellowship, Bell Museum; IMPLICATIONS FOR RECONSTRUCTING THE Richard Estes Memorial Grant, Society of Vertebrate DIETS OF EXTINCT FOSSIL SQUAMATES Paleontology.

Whiting, Evan, Fox, David L. Dinosaur Systematics, Diversity & Ecology Earth & Environmental Sciences, University of Minnesota, Minneapolis, Minnesota, U.S.A. A JUVENILE DIPLODOCID SAUROPOD FROM THE MORRISON FORMATION (LATE ) Dental topography analysis has emerged as a powerful PRESERVING A SKIN IMPRESSION quantitative tool for dietary reconstructions of fossil vertebrates, with multiple, homology-free metrics capable Whitlock, John A.1, Smith, Kathlyn2, Winters, Samuel2 of distinguishing among different dietary categories. So 1Biology, Mount Aloysius College, Cresson, Pennsylvania, far, these methods have almost entirely been applied to U.S.A., 2Geology and Geography, Georgia Southern mammals, but more recent applications to non-mammalian University, Statesboro, Georgia, U.S.A. vertebrates have shown great promise. Further application of these techniques to non-mammalian vertebrates could Carnegie Museum of Natural History (CM) specimen provide novel or enhanced insights into the quantitative 41682 consists of a fragment of a dorsal rib, five associations between tooth morphology and diet incomplete dorsal neural arches, and a small (12 x 5 cm), throughout vertebrate evolution. subtriangular skin impression. Originally collected by Earl Squamate reptiles (lizards and snakes) constitute one of the Douglass in 1910 from Dinosaur National Monument most taxonomically and ecologically diverse clades of (Tithonian; Morrison Formation; Utah, U.S.A.), the skin terrestrial vertebrates. Squamate diets fall along a impression was discovered much later during subsequent continuum from carnivory to herbivory, often with preparation. CM 41682 is a diplodocoid sauropod based overlapping intermediate dietary categories. Previous upon the lack of flaring triangular processes on the dorsal dental topography work on extant squamates has relied on neural spine; it is furthermore assignable to the geographic information systems (GIS) methods, in which successively less inclusive clades Flagellicaudata (based tooth surfaces are converted into digital elevation models upon the presence of ventrally conjoined instead of being treated as three-dimensional surface centropostzygapophyseal and posterior meshes. For our study, we used computed centrodiapophyseal laminae) and Diplodocidae (based to generate high-resolution, upon the presence of a posterior centroparapophyseal three-dimensional dentary tooth row surface meshes for 66 lamina). The early loss of bifurcation (here incipient by, at extant, pleurodont species of lizards and snakes. We latest, the sixth dorsal) and the early migration of the assigned each species to one of four dietary categories parapophysis to a position level with the zygapophyseal (herbivore, omnivore, invertivore, carnivore) based on data table both suggest affinities with either Apatosaurus or from the literature. Then, using molarR and Barosaurus; the lack of an accessory lamina on the CloudCompare, we obtained values for each of our surface spinodiapophyseal lamina differentiates CM 41682 from meshes for the following dental topography metrics: Barosaurus and makes a referral to Apatosaurus the most Orientation Patch Count Rotated (OPCR), Dirichlet likely conclusion. Normal Energy (DNE), and Ambient Occlusion (PCV). The skin impression preserves approximately 32 distinct, All three metrics are capable of differentiating between non-overlapping scale impressions, ranging from dietary categories, although their efficacy varies. OPCR