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Cranial and post-cranial variation is described for a large series of specimens of spectacled porpoise from Argentina and compared with that for specimens from other areas of the Southern Hemisphere. Condylobasal length in 54 adult skulls was 276-424. Tooth counts were 16-26 and 17-23 in the upper and lower jaws, respectively. Total number of vertebrae (n = 20) was 66-70. The rostrum may be relatively smaller in the Auckland Islands than in other regions.

Most tapirs are good seed dispersers. An exception is the Malayan tapir, Tapirus indicus, a seed predator (mainly of large seeds). Little is known about the capacity for tapirs to disperse seeds throughout their evolutionary history. We used the occlusal surface area (OSA) of tapir cheek teeth as a predictor of seed dispersal potential in living and extinct tapir species. We used T. indicus as a reference for an extant tapir that mostly eats seeds. The OSA was calculated by multiplying the maximal width and length of molars and premolars. A threshold based on T. indicus OSA was projected onto a box plot analysis and used as a predictor for tapir seed dispersal potential. Ordination and statistical results suggest that tooth morphology is uniform between Tapirus species and that size is the main factor affecting variation. Maxillary teeth show greater variation in morphology than mandibular teeth between species. The results suggest that extant South American tapirs are good seed dispersers. North American tapirs present variable OSAs, and Asian tapirs have a low capacity for dispersion. All European tapirs were probably efficient seed dispersers. We present the first morphometric evidence for seed dispersal capacity in tapirs, with ramifications for tapir palaeoecology.

Isotopes are one of the best tools to reconstruct the paleoecology of extinct taxa, allowing us to evaluate their diet (through carbon; C3 and C4 plants), their niche breadth (BA) and the environment in which they lived. In the present work we go deeper in the use of isotopes, and explore a mathematical mixing model with the stable isotopic composition of one (carbon) and two elements (carbon and oxygen) to evaluate (i) the relative contributions of three types of food resources (leaves, fruits and C4 grass) for meso- and megaherbivores (body mass > 100 kg) that lived during the late Pleistocene in Sergipe, Brasil, and (ii) which of these herbivores (together with some faunivorous taxa) could be potential preys for Smilodon populator and Caiman latirostris. Finally, we reconstructed the paleoenvironment in which the vertebrate community of Sergipe lived and concluded that the environment of Sergipe was a closer and drier landscape than African savannah nowadays, at least between 27 ka to 11 ka. Keywords: Quaternary, mammals, paleoecology, South America, stable isotopes. Isotopos sao uma das melhores ferramentas para reconstruir a Paleoecologia de taxons extintos, permitindo sugerir dieta (por meio do carbono, plantas C3 e C4), o nicho ecologico (BA) e ambiente em que viveram. No presente artigo nos aprofundamos no uso dos isotopos, e exploramos um modelo matematico misto com um isotopo (carbono) e dois isotopos (carbono e oxigenio) (i) para sugerir tres recursos tipos de recursos alimentares (folhas, frutas e gramineas C4) para meso-megaherbivoros (massa corporal acima de 100 kg) que viveram no Pleistoceno final de Sergipe, Brasil, e (ii) qual desses herbivoros (juntamente com faunivoros) foram presas potenciais de Smilodon populator e Caiman latirostris. Por fim, reconstruimos o paleoambiente na qual a comunidade de vertebrados de Sergipe viveu, concluindo que eramais fechada e seca do que as savanas da Africa atualmente, pelo menos entre 27 mil a 11 mil anos atras. Palavras-chave: Quaternario, paleoecologia, America do Sul, isotopos estaveis.

The first chondrichthyan teeth, dermal and oropharyngeal denticles from the Lower Cretaceous lacustrine Quirico Formation (Sanfranciscana Basin), in southeastern Brazil are described. Eight microre...

The earliest record of North American mammals in South America is significant for constraining the timing of intercontinental faunal interchange. At present, the oldest securely dated remains of a North American terrestrial mammal in South America pertain to a late Miocene procyonid; a few other North American mammal groups are present in late Miocene and early Pliocene outcrops in South America, but most are not recorded until the late Pliocene or Pleistocene, after the complete emergence of the Panamanian Isthmus. This long-established pattern has recently been called into question by reports of a proboscidean, two tayassuids, and a dromomerycine cervoid in supposed late Miocene deposits of Peruvian Amazon. In this contribution, we analyze the taxonomic identities and stratigraphic provenances of the tayassuid and dromomerycine fossils in detail. We conclude that these specimens are not distinguishable from modern tayassuids (Tayassu pecari and Dicotyles tajacu) and cervids, and that previous taxonomic identifications are based on misinterpretation of characters or inadequate specimens. In addition, there is insufficient evidence to support a late Miocene age for these terrestrial cetartiodactyl fossils; the stratigraphic provenance of the specimens is highly dubious, and the fossils are likely Quaternary in age., Facultad de Ciencias Naturales y Museo

We report the first radiocarbon datings and carbon (δ13C) and oxygen (δ18O) stable isotopes data to reconstruct the paleoecology of medium to large herbivorous mammals from late Quaternary of southwestern Amazon (Acre and Rondonia states, Brazil). AMS 14C dates for Neochoerus sp. (29,072 - 27,713 Cal yr BP), Notiomastodon platensis (25,454 - 24,884 Cal yr BP) and Eremotherium laurillardi (11,320 - 11,131 Cal yr BP) support the Lujanian ages. All fossils have low δ13C and δ18O isotopic values that suggest C3-dominated environments from closed canopy forests to wooded savannas, agreeing with paleovegetation reconstitution. Most species were browsers (piC3=100%; Niche breadth, BA=0), where the key species with the largest body mass, N. platensis (∼6,300 kg) and E. laurillardi (∼3,500 kg), possibly had a more generalized browser diet in closed-canopies to woodlands. Their diet distinguished from the C3/C4 generalist Trigodonops lopesi (∼1,900 kg), which foraged in wooded savannas (piC3=70%; BA=0.72), similarly with its relative Toxodon platensis (∼1,800 kg) that had a browse-dominated mixed feeder diet (piC3 ≥ 84%, BA ≤ 0.38) in Peruvian and Bolivian Amazon localities. Palaeolama major (∼280 kg) was possibly a strictly folivorous within forest canopies, whereas Tapirus sp. (∼250 kg) and Mazama sp. (∼40 kg) were browsers in closed-canopies to woodlands. Holmesina rondoniensis (∼120 kg) was a browser but not restricted, where could also feed on herbaceous from understories in woodlands, and Neochoerus sp. (∼200 kg) feeding predominantly herbaceous plants in wooded savannas (piC3=∼69%; BA=0.75). We estimate that the interspecific competition could have been avoid by different feeding strategies, although more investigations are still needed to better understand their ecological interactions in the habitats of the southwestern Amazon during the late Quaternary.

The contents of the superfamily Platanistoidea, an early-diverging lineage comprising extinct species and a single extant representative of South Asian river dolphin (Platanista gangetica), remain controversial. We describe here a partial skull and associated tympano-periotic bones identified as a new genus and species, Aondelphis talen gen. et sp. nov., collected in the lower levels of the Gaiman Formation (early Miocene), in Patagonia (Chubut Province, Argentina). Aondelphis is the first Patagonian platanistoid species named in almost a century. Phylogenetic analyses suggest Aondelphis talen gen. et sp. nov. and a taxon from New Zealand (cf. Papahu ZMT-73) are basal Platanistoidea sensu lato. Unambiguous synapomorphies related to the ear bones allowed us to determine its phylogenetic position. Aondelphis talen markedly differs from the other well-known early Miocene Patagonian platanistoid Notocetus, suggesting the coexistence of at least two different morphotypes that may have occupied different ecological niches at that time. The putative close relationship with a species from New Zealand indicates there was a rapid diversification and widespread distribution of the group in the Southern Hemisphere during the early Miocene. The description of new species and revision of historical records of Patagonian platanistoids can help shedding light on cetacean assemblages of the Patagonian sea during this epoch. Fil: Viglino, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina Fil: Buono, Mónica Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina Fil: Gutstein, Carolina. Universidad de Chile; Chile. Consejo de Monumentos Nacionales. Área Patrimonio Natural; Chile Fil: Cozzuol, Mario Alberto. Universidade Federal de Minas Gerais; Brasil Fil: Cuitiño, José Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina

Tapirs are perissodactyl ungulates of the genus Tapirus. The family Tapiridae was more diverse in the past. Genus Tapirus include five living species: T. indicus, T. pinchaque, T. bairdii, T. terrestris, and T. kabomani. Despite all the information available about tapirs, evolutionary relationships among species within the genus are still uncertain. Recent works suggest that T. terrestris may be a species complex. A better understanding of the evolutionary history of this clade is essential to better support conservation strategies for the species of this genus, which are keys in the dynamics of tropical forests in Southeast Asia and Central and South America. Geometric morphometry has been proved to be a useful tool for the study of morphological evolution in mammals, but studies involving cranial geometric morphometry of tapiroids have never been done. We hereby propose landmarks for the study of tapir cranial shape through 2D geometric morphometric technique, including 20 in lateral cranial view (n = 71), 14 in dorsal cranial view (n = 51), and 21 in ventral cranial view (n = 44), followed by PCA multivariate statistical analysis that ordinated specimens from each of the three data groups along the major axis of shape variation. Lateral and dorsal view landmarks proved to be the most diagnostic for the species studied, providing interesting insights and trends on tapiroid cranial evolution. Ventrally, the species analyzed do not differentiate significantly. In this paper, we add new information to the current cranial morphometric database of tapirs, which can help elucidate questions about their evolutionary history.

Tayassuidae is a family of pig-like Artiodactyla restricted to the New World. Despite its rich fossil history, they have received less attention from a taxonomic and phylogenetic perspective when compared to the Old World pigs, Suidae. In this study, we performed a computer assisted phylogenetic analysis using morphological and molecular data including fossil and extant Tayassuidae, using parsimony and Bayesian approaches. We recovered the monophyly of the family Tayassuidae, confirming previous proposals, as well as the monophyly of the subfamilies Hesperhyinae and Tayassuinae, and the genus Platygonus, which we placed in a new taxon of tribe level. The three living peccaries and a number of fossil species belong to a new, tribe level, monophyletic group. The genus Catagonus comes out as paraphyletic, leading us to propose to restrict the generic name to the type species, C. metropolitanus, and a new taxonomic arrangement for the remaining species previously included in it, revalidating the genera Brasiliochoerus and Parachoerus, and describing a new genus, Protherohyus, gen. nov. Fil: Parisi Dutra, Rodrigo. Universidade Federal de Minas Gerais; Brasil Fil: Casali, Danield Melo. Universidade Federal de Minas Gerais; Brasil Fil: Missagia, Rafaela Velloso. Universidade Federal de Minas Gerais; Brasil Fil: Gasparini, Germán Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina Fil: Perini, Fernando Araujo. Universidade Federal de Minas Gerais; Brasil Fil: Cozzuol, Mario Alberto. Universidade Federal de Minas Gerais; Brasil

Factors such as the discordance on the choice of characters by different authors and the fragmentary condition of the majority of fossils are responsible for many issues on the taxonomy of the South American Tayassuidae. The extinct Tayassuidae species Catagonus stenocephalus (Lund in Reinhardt 1880) presents a confuse nomenclatural history and a questionable genus designation. The morphometric analysis performed in this study, based on craniomandibular and dental characters, allowed to distinguished three groups morphologically distant from each other within the Catagonus genus. This result highlights the need for more precise phylogenetic analysis for the definition of taxonomic groups in the South American Tayassuidae.

New records of Catagonus stenocephalus and Tayassu pecari are reported from the karst of Serra da Bodoquena, located at a south-western portion of Brazil near the border with Paraguay. Skull and lower jaw fragments at different stages of mineralisation were retrieved from two limestone underwater caves, Japonês and Nascente do Formoso, associated with clay and sand deposits with no retrievable stratigraphy. C14 dating of fossil mammals from these caves was attempted, but so far no success was achieved, but the inferred age for the associated paleofauna of these caves is Late Pleistocene and Holocene. The morphology of these fossil peccaries, from the most south-western known population in Brazil, is detailed and paleoecological implications are considered. Fil: Parisi Dutra, Rodrigo. Universidade Federal de Minas Gerais; Brasil Fil: Missagia, Rafaela Velloso. Universidade Federal de Minas Gerais; Brasil Fil: Perini, Fernando Araujo. Universidade Federal de Minas Gerais; Brasil Fil: Cozzuol, Mario Alberto. Universidade Federal de Minas Gerais; Brasil Fil: Gasparini, Germán Mariano. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Guedes, Patricia Gonçalves. Universidade Federal do Rio de Janeiro; Brasil Fil: Salles, Leandro de Oliveira. Universidade Federal do Rio de Janeiro; Brasil

Isotopes are one of the best tools to reconstruct the Paleoecology of extinct taxa, yielding insights about their diet (through carbon; C3and C4plants), niche breadth (BA) and the environment in which they lived. In the present work we go deeper in the use of isotopes and explore a mathematical mixing model with the stable isotopes of two elements (carbon and oxygen) to (1) suggest the relative contribution of four types of food resources (leaves, fruits, roots and C4grass) for meso- and megaherbivores (weight > 100 kg) that lived in the Late Pleistocene of Poço Redondo, Sergipe, Brasil, and (2) evaluate which of these herbivores could be the potential prey for the carnivoresSmilodon populatorandCaiman latirostris. To explore the intra/interspecific competition of these fauna, we generate weight estimation, standardized niche breadth (BA) for the meso-megamammals from Sergipe and compare with data from the meso-megaherbivores from Africa, concluding thatEremotherium laurillardiandToxodon platensiswere the best resource competitors in the Late Pleistocene of Sergipe, and reinforcing their importance as key species in this extinct community. Finally, we reconstructed the paleoenvironment in which the vertebrate community of Sergipe lived, estimating Mean Annual Temperature (°C), Mean Annual Precipitation, Biomass and Energy Expendidure, noting that environments in the Late Pleistocene of Sergipe were similar to those of Africa nowadays, but hotter and with more energy expenditure for these meso-megamammals.

A specimen of a remarkable new catfish genus and species was collected in middle/late Miocene marine beds of the Puerto Madryn Formation at the base of the marine cliff of the sea lion colony area near Puerto Pirámide, southern coast of Península Valdés, northeastern Patagonia, Argentina. Siluriforms (catfishes) constitute a most important monophyletic ostariophysan group of mainly freshwater fishes that occurs in almost all continents but it is especially diverse in South America. Catfishes are presently distributed in tropical to temperate areas and a small number of species are marine or amphibiotic. The new catfish shows many primitive features for catfishes in the maxilla, autopalatine, hyal elements, and Weberian apparatus. The genus is clearly distinguished by four autapomorphies: sand clock–shaped autopalatine, posterior limb of autopalatine widening strongly, post-articular arm of autopalatine longer, and a metapterygoid longer than broad. One tree was obtained both under equal and implied weighting with the following topology: a basal polytomy in the Siluriformes formed by Diplomystidae, Bachmanniidae, Kooiichthys and the Siluroidei. The new species appears to have been a marine or amphibiotic taxon: it was collected in beds considered to represent the Maximum Flooding Horizon of the transgression that deposited the Puerto Madryn Formation. The coast at this moment was at approximately 90 km to the west. According to faunistic evidence, the sea was warm temperate.

This study compares the bony ear morphology of freshwater and marine odontocetes (toothed whales). Odontocetes are unique among marine mammals in two important respects: 1) they use echolocation; 2) at least three lineages have independently evolved obligate freshwater habits from marine ancestries. Freshwater odontocetes include the so-called “river dolphins,” a paraphyletic group that each evolved convergent external morphological characters that distinguish them from oceanic dolphins (Delphinoidea). In addition to their convergent external morphology, “river dolphins” all have echolocation that use one peak (narrow-band) frequency around 100 kHz, compared to oceanic delphinoids which use a two peak (bimodal) frequency ranging from 40 to 140 kHz. The differences in echolocation suggest that the sensory systems responsible for detecting these different sound frequencies should also differ, although quantitative assessments of the cetacean hearing system remain understudied and taxonomically undersampled. To test if ear bone morphology reflects underlying environmentally driven differences in echolocation ability, we assembled a dataset of odontocete periotics (n = 114) from extant and fossil species. We examined 18 external and three internal linear periotic measurements, the latter of which were examined using cone-beam scanning tomography. Results from multivariate canonical ordination analyses show that periotic height, periotic thickness and pars cochlearis width collectively explain the largest amount of interspecific variation in our dataset. Because these particular ear bone measurements correspond to acoustic hearing ranges, we propose that they are also proxies for environmental preference (i.e., marine, freshwater and intermediate habitats) and may be useful for deciphering environmental preferences of extinct odontocetes.

“River dolphins” are a paraphyletic group of toothed whales (Odontoceti) that represent independent secondary invasions of freshwater habitats. Different “river dolphin” lineages display suites of convergent morphological specializations that commonly reflect adaptations to riverine and freshwater environments, such as longirostry, reduced orbits, and wide, paddle-like flippers. One lineage, the Iniidae, is presently endemic to South America, and includes several extinct Neogene taxa along with their sole extant genus, Inia (the Amazon River dolphin). We report here a humerus recovered from the late Miocene deposits of the Ituzaingo Formation in the Parana Basin of Argentina. The specimen exhibits diagnostic features of the family Iniidae, including a scapular-sternal joint of the humerus, which is a unique anatomical connection among mammals. This joint permits enhanced parasagittal adduction of the flipper as a control surface, relative to other odontocetes, providing Inia with a high degree of maneuverability in its structurally complex and heterogenous riverine habitat. This unique anatomical connection, here documented from the late Miocene (∼9 million years–6.5 million years old), not only provides the oldest diagnostic record for Iniidae, but it also indicates a similar habitat use for this lineage, a finding coincident with the current paleoenvironmental interpretation for the Ituzaingo Formation. Anat Rec, 297:1096–1102, 2014. © 2014 Wiley Periodicals, Inc.

The genus Trichechus (Mammalia, Sirenia, Trichechidae) harbors a modest diversity, comprising only three living species of manatees, and no species currently recognized as fossil. Herein, we report...

We investigated the radiocarbon age and stable isotope composition of bioapatite from bone, enamel, and dentine material from 3 different species of extinct mammals in South America. Most samples of Eremotherium laurillardi, Toxodon platensis, and Notiomastodon platensis were collected in natural depressions located in the northeastern Brazilian provinces of Sergipe, Bahia, and Rio Grande do Norte. All samples studied were devoid of collagen, which had decomposed as a result of high microbiological activity in this tropical region. We have instead analyzed the bioapatite fraction of the samples, which was relatively well preserved even in these harsh tropical conditions. The mineral fraction of bone and tooth material does not usually undergo microbiological decomposition but may be exposed to isotopic exchange with environmental carbonates. The problem thus becomes one of separating the diagenetic carbonates without destroying the bioapatite. We offer a technique for removing the secondary diagenetic carbonates by treatment with diluted acetic acid in a vacuum. We also demonstrate that proper pretreatment of bone and tooth samples allows the separation of diagenetic carbonates from bioapatite, as long as the carbon in these samples has not degraded completely. Bone, enamel, and dentine samples from individuals of the 3 mammalian species were dated using this technique and were compared to results by other researchers from the literature. Date ranges for the species presented were in good agreement with prior research. A comparison with other dating techniques such as U/Th and ESR shows the reliability of the treatment described and the feasibility of 14C dating the bioapatite fraction given certain conditions. In 2 cases, we dated bone enamel and dentine samples from the same individuals of N. platensis, with results between 14 and 21 ka. Results from dating samples of T. platensis are between 11.5 and 13 ka. The oldest tissue in both cases was dentine. The dating of enamel and dentine from the same species did not show regular differences; however, more often the dentine material was older. The oldest date, ≃22.5 ka for E. laurillardi, was obtained on the bioapatite fraction of dentine.

During the Pleistocene a fauna composed of large (biomass > 44 kg) and giant mammals (biomass > 1000 kg) that are usually associated with open environments lived in the Brazilian Intertropical Region. We present here new information concerning the paleoecology and chronology of some species of this megafauna. Carbon isotope analyses were performed for a better understanding of the paleoecology of the species Eremotherium laurillardi (Lund, 1842), Notiomastodon platensis (Ameghino, 1888) and Toxodon platensis (Owen, 1849). The δ13C data allow attributing a generalist diet to these species, which varied according to the kind of habitat in which they lived. In more open habitats all species were grazers; in mixed habitats E. laurillardi and T. platensis were mixed feeders, and N. platensis was grazer; and in more closed habitats all species were mixed feeders.

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Jr Coll, Santa Rosa, CA USA George Washington Univ, Washington, DC 20037 USA Inst Teknol Bandung, Bandung, Indonesia Earlham Coll, Richmond, IN USA Senckenberg Forschungsinst & Nat Museum, Frankfurt, Germany Univ Estadual Londrina, Londrina, Parana, Brazil Univ Koblenz Landau, Koblenz, Germany Nat Hist Museum, London, England Ditsong Natl Museum Nat Hist, Pretoria, South Africa Bombay Nat Hist Soc, Bombay, Maharashtra, India Philipps Univ Marburg, Marburg, Germany Hess Landesmuseum, Darmstadt, Germany Smithsonian Conservat Biol Inst, Washington, DC USA Univ Pannonia, Keszthely, Hungary Staatliches Museum Nat Kunde, Stuttgart, Germany UFT, Tocantins, Portugal Museum Nat Kunde, Berlin, Germany Nat Hist Riksmuseet, Stockholm, Sweden Hikarigaoka, Munakata, Japan Inst Agr & Environm Sci, Tartu, Estonia Univ Los Andes, Merida, Venezuela Bat Jungle, Monteverde, Costa Rica Texas A&M Univ, College Stn, TX USA Yale Univ, New Haven, CT USA Univ Estadual Paulista, Sao Jose Do Rio Preto, Brazil 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Smithsonian Inst, Washington, DC 20560 USA Nat Hist Museum & Inst, Chiba, Japan Senckenberg Biodiversitat & Klima Forschunsgzentr, Frankfurt, Germany Marquette Univ, Milwaukee, WI 53233 USA Univ Firenze, Museo Storia Nat, Florence, Italy Univ Fed Bahia, Salvador, BA, Brazil Fed Univ ABC, Sao Bernardo, Brazil Univ Fed Goias, Goiania, Go, Brazil Univ Alaska Museum, Fairbanks, AK USA Egerton Univ, Egerton, Kenya Museo Hist Nat, Lima, Peru IKIAM Univ Reg Amazon, Tena, Ecuador Univ Hyogo, Sanda, Japan Inst Rech Dev, Paris, France Univ Sao Paulo, Piracicaba, Brazil Niedersachs Landesbetrieb Wasserwirtschaft Kusten, Hannover, Germany Univ Complutense Madrid, Madrid, Spain Consejo Nacl Invest Cient & Tecn, Ctr Nacl Patagon, Puerto Madryn, Argentina Roosevelt Univ, Coll Profess Studies, Chicago, IL 60605 USA Western Kentucky Univ, Bowling Green, KY 42101 USA Univ Naples Federico II, Naples, Italy Univ Fed Acre, Rio Branco, Acre, Brazil Univ Fed Santa Catarina, Florianopolis, SC, Brazil Inst Bio & Geociencias Noroeste Argentino, Salta, Argentina Inst Venezolano Invest Cient, Caracas, Venezuela Umweltbundesamt, Vienna, Austria Penclen, Plumelec, France CNRS MNHN UPMC, Ctr Rech Paleobiodivers & Paleoenvironm, Paris, France Staatl Museum Nat Kunde, Stuttgart, Germany Consejo Nacl Invest Cient & Tecn, Museo Argentino Ciencias Nat Bernardino Rivada, Buenos Aires, DF, Argentina Ctr Biol Gest Populat INRA, Montferrier Sur Lez, France Loyola Univ Chicago, Chicago, IL USA Pontificia Univ Catolica Rio do Sul, Porto Alegre, RS, Brazil Durban Museum Nat Sci, Durban, South Africa Univ Estado Amazonas, Manaus, Amazonas, Brazil Brigham Young Univ, Provo, UT 84602 USA Museo Hist Nat La Salle, Caracas, Venezuela Univ Vet Med Hannover, Hannover, Germany Australian Museum, Sydney, NSW, Australia Texas Tech Univ, Lubbock, TX 79409 USA Francis Marion Univ, Florence, SC USA Univ Washington, Seattle, WA 98195 USA Univ Connecticut, Groton, CT USA Fed Univ ABC, Santo Andre, SP, Brazil Univ Fed Uberlandia, Uberlandia, MG, Brazil Fed Univ Para, Belem, Para, Brazil Yale Peabody Museum, New Haven, CT USA Univ Texas Arlington, Arlington, TX 76019 USA Senckenberg Deutsch Entomol Inst, Muncheberg, Germany CSIRO, Natl Res Collect, Canberra, ACT, Australia Univ Venda, Thohoyandou, South Africa Univ Ulsan, Ulsan, South Korea Univ Estadual Sao Paulo, Botucatu, SP, Brazil Senckenberg Forsch Inst & Nat Museum, Frankfurt, Germany Ocean Univ China, Inst Marine Biodivers & Evolut, Qingdao, Shandong, Peoples R China Univ Fed Para, Altamira, Brazil Univ Estadual Paulista, Assis, Brazil UPMC, Ctr Rech Paleobiodiversite & Paleoenvironm, CNRS, MNHN, Paris, France Tech Univ Kaiserslautern, Kaiserslautern, Germany Charles Univ Prague, Dept Zool, Prague, Czech Republic Univ Nacl Expt los Llanos Occident Ezequiel Zamor, Guanare, Venezuela Long Isl Univ, Brooklyn, NY USA Univ Ryukyus, Okinawa, Japan Pontificia Univ Catolica Ecuador, Museo Zool, Escuela Ciencias Biol, Quito, Ecuador Indiana Univ Penn, Indiana, PA USA IRD, Dakar, Senegal State Museum Nat Hist Karlsruhe, Karlsruhe, Germany Univ Toulouse III Paul Sabatier, Toulouse, France Univ Ghent, Ghent, Belgium Univ Antwerp, Antwerp, Belgium Karlsruhe Inst Technol, Karlsruhe, Germany Ctr Cellular & Mol Biol, Hyderabad, India Univ Fed ABC, Santo Andre, Brazil Yale Peabody Museum Nat Hist, New Haven, CT USA Univ Innsbruck, Mondsee, Austria Bethune Cookman Univ, Daytona Beach, FL USA Natl Museum Nat & Sci, Tokyo, Japan Zool Garten Koln, Cologne, Germany Univ Estadual Paulista, Botucatu, SP, Brazil Univ Estadual Paulista, Sao Vicente, Brazil Univ Estadual Paulista, Rio Claro, Brazil Univ Estadual Paulista, Sao Jose Do Rio Preto, Brazil Univ Estadual Paulista, Assis, Brazil

The formation of the Isthmus of Panama stands as one of the greatest natural events of the Cenozoic, driving profound biotic transformations on land and in the oceans. Some recent studies suggest that the Isthmus formed manymillions of years earlier than the widely recognized age of approximately 3 million years ago (Ma), a result that if true would revolutionize our understanding of environmental, ecological, and evolutionary change across the Americas. To bring clarity to the question of when the Isthmus of Panama formed, we provide an exhaustive review and reanalysis of geological, paleontological, and molecular records. These independent lines of evidence converge upon a cohesive narrative of gradually emerging land and constricting seaways,withformationof theIsthmus of Panama sensustricto around 2.8 Ma. The evidence used to support an older isthmus is inconclusive, and we caution against the uncritical acceptance of an isthmus before the Pliocene., Facultad de Ciencias Naturales y Museo

This chapter reviews information about the extinct fauna that lived in the Brazilian Intertropical Region (BIR) between 64 and 10 ka B.P. Data from the available literature regarding dating (14C, ESR, U-series) and paleodiet reconstruction (δ13C) for some of taxa of the BIR are herein presented. Furthermore, paleoenvironmental reconstructions of two climatic moments are presented, one at 64 ka, and another between 27 and 10 ka B.P.

In South America, one of the most important themes is the effort to discover the diet of the extinct giant mammals that lived in this continent. This paper presents new data for the species Palaeolama major, acquired by the analysis of plant fragments found in coprolites. This species possibly lived in an open area, feeding on shrubs, in the forest border.

The South American gomphotheres were previously classified in three genera and three species. Two biogeographic corridors are recognized for the dispersion of gomphotheres in South America. Cuvieronius hyodon was found mainly in the highlands and west to the Andes, and Stegomastodon platensis and Haplomastodon chimborazi were found in lowlands. The aim of the present study is to review the taxonomy of South American lowland gomphotheres. A large sample of specimens was analyzed, which included crania, teeth and postcrania from several localities in Brazil, Ecuador, Colombia, Venezuela, Argentina, and Uruguay. A review of the diagnostic characters proposed in previous taxonomic studies of South American lowland gomphotheres found that they are variable in both reputed species if large samples are considered. There is no support for more than one South American lowland gomphothere species, and it shows a significant morphological variation in some characteristics. The name for this taxon, after a taxonomic review, must be Notiomastodon platensis (Ameghino, 1888) new combination. This reduces the number of gomphothere species in South America to two genera and species. The lowland gomphothere is closely related to Cuvieronius and Rhynchotherium, and not closely related to Stegomastodon from North America, and Sinomastodon from Asia.

The taxonomic history of South American Gomphotheriidae is very complex and controversial. Three species are currently recognized: Amahuacatherium peruvium, Cuvieronius hyodon, and Notiomastodon platensis. The former is a late Miocene gomphothere whose validity has been questioned by several authors. The other two, C. hyodon and N. platensis, are Quaternary taxa in South America, and they have distinct biogeographic patterns: Andean and lowland distributions, respectively. South American gomphotheres became extinct at the end of the Pleistocene. We conducted a phylogenetic analysis of Proboscidea including the South American Quaternary gomphotheres, which resulted in two most parsimonious trees. Our results support a paraphyletic Gomphotheriidae and a monophyletic South American gomphothere lineage: C. hyodon and N. platensis. The late Miocene gomphothere record in Peru, Amahuacatherium peruvium, seems to be a crucial part of the biogeography and evolution of the South American gomphotheres.

The systematics of gomphotheres in South America is confused, and the status of some taxa is still subject to discussion. Recently, Prado and Alberdi published a cladistic analysis of the trilophodont gomphotheres, with emphasis on the South American species. Unfortunately, the paper has problems in many points, which invalidates the phylogeny itself and the biogeographic analysis of Alberdi et al. based on it. This paper reviews the problems of the analysis of Prado and Alberdi. The main problems of their analysis are: poor taxon sampling, exclusion of non-South American species of genera present in South America, inadequate choice of outgroup, use of outdated software and methodology, and several mistakes in coding of characters. Rebuilding of the original character matrix and analysis using TNT software resulted in a new consensus tree from five equally parsimonious trees. In the analysis, Rhynchotherium , Sinomastodon , Gnathabelodon , Eubelodon and a clade containing the three South American taxa form a polytomy that have Gomphotherium as a sister group. Sinomastodon and Gnathabelodon were successive branches toward the South American taxa in Prado and Alberdi’s result. The main point of this contribution is to correct the errors in the original analysis and character coding, including polymorphism when necessary, and to use updated software and weighting strategy. The result is much less resolved than that of Prado and Alberdi, but is has a strong influence on the conclusions that those authors drew from the original phylogeny and the biogeographic implication presented in Alberdi et al.

Fil: Perez, Leandro Martin. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Division Paleozoologia Invertebrados; Argentina

Two biogeographical units are generally recognized in the present shelf area of Argentina: the Magellanian and Argentinian Provinces. The two provinces differ in their fossil record. The evolution of these provinces has been characterized by migrations, extinctions, pseudoextinctions and, perhaps, even speciation events. Marine vertebrate assemblages with some similarities to the Argentinian fauna were already present in the Miocene, whereas no associations similar to those of the Magellanian fauna have been found in South America before the Pleistocene. Two successive major marine transgressions flooded northern Patagonia during the Miocene: the ‘Patagoniense’ (Early Miocene) and the ‘Entrerriense’ (Middle to Late Miocene). We analyse three rich fossil assemblages that were formed during these transgressions. The absence of Magellanian Miocene vertebrate assemblages is consistent with the hypothesis of a more southern distribution of the cold-temperate fauna at that time. In Patagonia, as in other regions, an increased number of living groups appeared from the Lower to Upper Miocene. The Late Miocene aquatic mammals had a modern aspect, and some of the fish species are still living in the South Atlantic Ocean. In this contribution, we stress that warm-temperate fishes and a high diversity of penguins are found together at the base of the Gaiman Formation. We hypothesize that penguins were adapted to live in warmer waters than those of the latest Cenozoic and the Recent. Finally, we recall that many taxa became extirpated because of the global temperature drops of the late Cenozoic. However, some fishes and pinnipeds which were extirpated only in the Atlantic Ocean are discussed here. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103, 423–440.

On the basis of paleontological content (vertebrates and palynology) and facies analysis from river banks, road cuts, and three wells, we have assigned the uppermost levels of the Solimoes Formation in western Amazonia, Brazil, to the Late Miocene. The vertebrate fossil record from outcropping sediments is assigned to the Huayquerian–Mesopotamian mammalian biozones, spanning 9–6.5 Ma. Additionally, we present results that demonstrate that deposits in Peruvian Amazonia attributed to Miocene tidal environments are actually fluvial sediments that have been misinterpreted (both environmentally and chronologically) by several authors. The entire Late Miocene sequence was deposited in a continental environment within a subsiding basin. The facies analysis, fossil fauna content, and palynological record indicate that the environment of deposition was dominated by avulsive rivers associated with megafan systems, and avulsive rivers in flood basins (swamps, lakes, internal deltas, and splays). Soils developed on the flatter, drier areas, which were dominated by grasslands and gallery forest in a tropical to subtropical climate. These Late Miocene sediments were deposited from westward of the Purus arch up to the border of Brazil with Peru (Divisor Ranges) and Bolivia (Pando block). Eastward of the Iquitos structural high, however, more detailed studies, including vertebrate paleontology, need to be performed to calibrate with more precision the ages of the uppermost levels of the Solimoes Formation. The evolution of the basin during the late Miocene is mainly related to the tectonic behavior of the Central Andes (∼ 3°–15°S). At approximately 5 Ma, a segment of low angle of subduction was well developed in the Nazca Plate, and the deformation in the Subandean foreland produced the inland reactivation of the Divisor/Contamana Ranges and tectonic arrangements in the Eastern Andes. During the Pliocene southwestern Brazilian Amazonia ceased to be an effective sedimentary basin, and became instead an erosional area that contributed sediments to the Amazon fluvial system. At that time, the lowland fluvial systems of southwestern Amazonia (the Purus, Jurua and Javari basins) become isolated from the Andes by the newly formed north-flowing Ucayali system and south-east flowing Madre de Dios System. It was during the early Pliocene that the Amazon fluvial system integrated regionally and acquired its present appearance, and also when it started to drain water and sediments on a large scale to the Atlantic Ocean.

JHOANN CANTO,1 RODOLFO SALAS-GISMONDI,*2 MARIO COZZUOL,3 and JOSE YANEZ4; 1Museo Nacional de Historia Natural, Secci6n Paleontologfa, Casilla 587, Santiago, Chile, jcanto@paleontologica.org; 2Departamento de Paleontologia de Vertebrados, Museo de Historia Natural, UNMSM, Av. Arenales 1256, Lima 14, Peru, rodsalasgis@yahoo.com; 3Laboratorio de Paleontologia. Museu de Ciencia e Tecnologia-PUCRS, Porto Alegre, RS, Brasil, mario.cozzuol@pucrs.br; 4Zoologia Secci6n, Museo Nacional de Historia Natural, Casilla 787, Santiago, Chile, jyanez@mnhn.cl

Cayaoa bruneti TONNI, 1979 is an early Neogene anseriform exhumed from marine sediments of the lower levels of the Gaiman Formation ("Patagoniano", Leonian Marine Stage, Chubut, Argentina). It was originally based on a partial tarsometatarsus that was not assigned to subfamily or tribe. We re-examine the holotype and study new tarsometatarsi, and previously undescribed skeletal elements including partial femora, tibiotarsi, partial humeri and carpometacarpi. Cayaoa bruneti was a strictly foot-propelled diving bird that exhibited an extreme reduction of the fore-limb, being probably the earliest recorded flightless duck. Similarly reduced wings are found in the distantly related anseriform Cnemiornis OWEN, 1866 of subrecent deposits of New Zealand, Chendytes MILLER, 1925 of the Pleistocene of California, and the moa-nalos of the Late Quaternary of Hawaii. Fil: Noriega, Jorge Ignacio. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina Fil: Tambussi, Claudia Patricia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Cozzuol, Mario Alberto. Pontificia Universidad Católica de Río Grande del Sur; Brasil

Fossil content (vertebrate paleofauna and palynology) indicates that the sediments of the Solimões Formation in Acre (SW Brazilian Amazonia) are continental, having been deposited by avulsive fluvial belts in a floodbasin-floodplain environment. The main source area was the Andes chain. Widespread lacustrine swampy deposits, stacked channel deposits, and paleosoils are typical elements that characterize the Solimões Formation sediments that outcrop in southwestern Brazilian Amazonia. New data on fossil vertebrate assemblages and palynology corroborate the Late Miocene age suggested previously and assign the fossils to the Huayquerian mammalian biozone, spanning 9-6.5 Ma. These geological and paleontological data show that the existence of an intracontinental seaway through SW Amazonia during the Late Miocene (11-10 Ma), connecting the Caribbean Sea with the Parana Basin as previously proposed is unsustainable, because the sediments used by previous authors to propose the seaway were deposited in a continental environment and are younger than 11-10 Ma. © 2006 Elsevier Ltd. All rights reserved. Fil: Latrubesse, Edgardo Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina Fil: da Silva, Silane A. F.. Ministerio de Ciencia, Tecnología E Innovacao. Instituto Nacional de Pesquisas Da Amazonia. Coordenacao de Pesquisas Em Entomologia; Brasil Fil: Cozzuol, Mario Alberto. Laboratorio de Paleontologia Museu de Ciências e Tecnologia, PUC-RS, Avda. Ipiranga 6681, Porto Alegre; Brasil Fil: Absy, Maria Lúcia. Ministerio de Ciencia, Tecnología E Innovacao. Instituto Nacional de Pesquisas Da Amazonia. Coordenacao de Pesquisas Em Entomologia; Brasil

The genus Tapirus has four living species and a disjunct distribution (America and Asia). Its fossil record extends back to the Oligocene in Europe and middle Miocene in North America, with more than 20 nominal species. We describe here three specimens from the Pleistocene of Rondonia and Acre states, southwestern Amazonia. Morphometric analysis indicates the presence of two morphotypes for the genus, which are different from the recent ones: a robust form, represented by Acre specimens, and a more gracile form represent by the specimens from Rondonia.

The vertebrate faunal assemblage associated with the Neogene deposits in the Acre region (southwestern Amazonia) is secured as Late Miocene on the basis of a correlation with the ‘Mesopotamian’ faunal assemblage from the Parana region of Argentina and Uruguay. Both assemblages occur in the time span of the Huayquerian South American Land Mammal Age (SALMA). The Acre, ‘Mesopotamian’ (Argentina and Uruguay), and Urumaco (Venezuela) assemblages are considered faunistically correlated and contemporaneous on the basis of their shared amniote taxa. The Laventan assemblage from Colombia has important faunistic affinities with the previous three but is older. A paleogeographic scenario is proposed to explain the long-distance correlation among those assemblages. On the basis of data from geology, field observations, fauna, and palynology, the validity of the Ucayali unconformity as a time marker along all of western Amazonia is rejected.

The record of Glyptotherium sp. in the Brazilian Northeastern region initiated a reinterpretation of the material previously assigned to Glyptodon and the distribution in the country. The most recent interpretation suggests that the materials found in the Brazilian Intertropical Region belong to Glyptotherium, with Glyptodon restricted to southern Brazil. However, two osteoderms with characteristics attributable to Glyptodon has been recently found in Sergipe State, Northeastern region, suggesting that the two genera occurred in this region during the Pleistocene.

Balaenidae (right and bowhead whales) are a key group in understanding baleen whale evolution, because they are the oldest surviving lineage of crown Mysticeti, with a fossil record that dates back ~20 million years. However, this record is mostly Pliocene and younger, with most of the Miocene history of the clade remaining practically unknown. The earliest recognized balaenid is the early Miocene Morenocetus parvus Cabrera, 1926 from Argentina. M. parvus was originally briefly described from two incomplete crania, a mandible and some cervical vertebrae collected from the lower Miocene Gaiman Formation of Patagonia. Since then it has not been revised, thus remaining a frequently cited yet enigmatic fossil cetacean with great potential for shedding light on the early history of crown Mysticeti. Here we provide a detailed morphological description of this taxon and revisit its phylogenetic position. The phylogenetic analysis recovered the middle Miocene Peripolocetus as the earliest diverging balaenid, and Morenocetus as the sister taxon of all other balaenids. The analysis of cranial and periotic morphology of Morenocetus suggest that some of the specialized morphological traits of modern balaenids were acquired by the early Miocene and have remained essentially unchanged up to the present. Throughout balaenid evolution, morphological changes in skull arching and ventral displacement of the orbits appear to be coupled and functionally linked to mitigating a reduction of the field of vision. The body length ofMorenocetus and other extinct balaenids was estimated and the evolution of body size in Balaenidae was reconstructed. Optimization of body length on our phylogeny of Balaenidae suggests that the primitive condition was a relatively small body length represented by Morenocetus, and that gigantism has been acquired independently at least twice (in Balaena mysticetus and Eubalaena spp.), with the earliest occurrence of this trait in the late Miocene-early Pliocene as represented by Eubalaena shinshuensis., Facultad de Ciencias Naturales y Museo

Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass stranding agent with broad geographical and widespread taxonomic impact. Toxin-mediated mortalities in marine food webs have the potential to occur over geological timescales, but direct evidence for their antiquity has been lacking. Here, we describe an unusually dense accumulation of fossil marine vertebrates from Cerro Ballena, a Late Miocene locality in Atacama Region of Chile, preserving over 40 skeletons of rorqual whales, sperm whales, seals, aquatic sloths, walrus-whales and predatory bony fish. Marine mammal skeletons are distributed in four discrete horizons at the site, representing a recurring accumulation mechanism. Taphonomic analysis points to strong spatial focusing with a rapid death mechanism at sea, before being buried on a barrier-protected supratidal flat. In modern settings, HABs are the only known natural cause for such repeated, multispecies accumulations. This proposed agent suggests that upwelling zones elsewhere in the world should preserve fossil marine vertebrate accumulations in similar modes and densities.

Genypterus valdesensis, sp. nov. from the Puerto Madryn Formation in Peninsula Valdes, Argentina is the first fossil ophidiid reported from South America and represents the first well preserved record of the genus worldwide. The specimen consists of a nearly complete articulated skull and some disarticulated postcranial elements. A thorough description is given of the osteological features of the species, which can be used to recognize it as a distinct taxon. The fossil species is characterized by the presence of a foramen on infraorbital 3 and by the square-shape of infraorbital 4. An array of morphological features taken in combination contribute to further differentiate G. valdesensis from the Recent species. This specimen also provides unequivocal evidence of the presence of the Ophidiiformes in the southwestern Atlantic Ocean 14 MA.

All known species of extant tapirs are allopatric: 1 in southeastern Asia and 3 in Central and South America. The fossil record for tapirs, however, is much wider in geographical range, including Europe, Asia, and North and South America, going back to the late Oligocene, making the present distribution a relict of the original one. We here describe a new species of living Tapirus from the Amazon rain forest, the 1st since T. bairdii Gill, 1865, and the 1st new Perissodactyla in more than 100 years, from both morphological and molecular characters. It is shorter in stature than T. terrestris (Linnaeus, 1758) and has distinctive skull morphology, and it is basal to the clade formed by T. terrestris and T. pinchaque (Roulin, 1829). This highlights the unrecognized biodiversity in western Amazonia, where the biota faces increasing threats. Local peoples have long recognized our new species, suggesting a key role for traditional knowledge in understanding the biodiversity of the region.

"River dolphins" are a paraphyletic group of toothed whales (Odontoceti) that represent independent secondary invasions of freshwater habitats. Different "river dolphin" lineages display suites of convergent morphological specializations that commonly reflect adaptations to riverine and freshwater environments, such as longirostry, reduced orbits, and wide, paddle-like flippers. One lineage, the Iniidae, is presently endemic to South America, and includes several extinct Neogene taxa along with their sole extant genus, Inia (the Amazon River dolphin). We report here a humerus recovered from the late Miocene deposits of the Ituzaingó Formation in the Paraná Basin of Argentina. The specimen exhibits diagnostic features of the family Iniidae, including a scapular-sternal joint of the humerus, which is a unique anatomical connection among mammals. This joint permits enhanced parasagittal adduction of the flipper as a control surface, relative to other odontocetes, providing Inia with a high degree of maneuverability in its structurally complex and heterogenous riverine habitat. This unique anatomical connection, here documented from the late Miocene (∼9 million years-6.5 million years old), not only provides the oldest diagnostic record for Iniidae, but it also indicates a similar habitat use for this lineage, a finding coincident with the current paleoenvironmental interpretation for the Ituzaingó Formation.

The objectives of the present study were to (1) provide new dates of Notiomastodon platensis (Ameghino, 1888) fossils from the Brazilian Intertropical Region, derived from Electron Spin Resonance (ESR); (2) propose a timeline for the occurrence of N. platensis in South America based on published data (ESR, 14C, 230Th/234U) and, finally, (3) propose a geographic distribution for the species over the period between 21 ka (Last Glacial Maximum) and 120 ka (Interglacial period). The new dates presented here, together with the available estimates, indicate that the species occurred in South America between at least 530 ka and 6 ka (middle Pleistocene–early Holocene). The Paleo-Species Distribution Models created for the 21 ka and 120 ka periods overlapped with the distribution of dry forest habitats during the Last Glacial Maximum, which clearly indicates that the species was associated with this type of vegetation.

The oldest known species of the genus Didelphis (Mammalia, Marsupialia, Didelphidae) is described here. The holotype and only known specimen comes from the late Miocene deposits of the Solimões Formation at Patos, Acre River, Brazil. The new species is one of only a few marsupials known from this assemblage. The new species differs from other known species by its smaller size, low mandibular ramus, smaller molars relative to premolars, and p3 with inflated crown. The last feature suggests more fmgivorous habits than in other species of the genus. © 2006 American Society of Mammalogists., Facultad de Ciencias Naturales y Museo

We report here a new fossil primate from the late Miocene of Brazil. The material consists of a lower first molar and a maxilla with P3-4. The fossils were collected in the Solimoes Formation at the locality of Patos, upper Acre River, Acre State, Brazil. The locality is assigned to the Huayquerian South American Land Mammal Age based on faunal content (late Miocene; dated to between 9 and 6 Ma). The new material is the oldest known occurrence of fossil primates in Brazil and is recognized as a new genus and species, Solimoea acrensis. Solimoea is the oldest known member of the ateline subfamily, which includes the living genera Ateles, Lagothrix, and Brachyteles. By analogy with the molar structures and diets of extant platyrrhines, Solimoea primarily had a diet of fruit, perhaps similar to that of the spider monkey, Ateles. Two other primate teeth described previously from the same formation in Bolivia document the occurrence of alouattines and cebines. One of those specimens is a late Miocene representative of the middle Miocene Colombian genus Stirtonia. The other represents one of the largest known platyrrhine primates, for which is erected a new primate genus, Acrecebus fraileyi.

fair-weather conditions. Marine-deltaic facies in an ever-shallowing, coarsening-upward transition overlie a transgressive shale lithofacies younger than the Sunbury. Upsection, prodelta, shoreface, bar-washover, and foreshore-beach facies contain a diverse assemblage of Bifungites, Helminthopsis, Monocraterion, Palaeophycus, Phycodes, Planolites, Rosselia, Rusophycus, Scalarituba, and Skolithos. Interdistributary bay shales contain Helminthopsis and Scalarituba deposit-feeding traces. Distributary mouth-bar deposits contain Monocraterion and Skolithos suspension-feeding traces in sandstone, and Helminthopsis, Planolites, and Scalarituba deposit-feeding traces in shale interbeds deposited under slack-water conditions. Hummocky cross-stratified sandstones, wave-rippled siltstones, and silty shales from inner shelf facies at Alta contain an ethologically diverse Cruziana Ichnofacies consisting of Arenicolites, Bifungites, Chondrites, Cruziana, Dolopichnus, Helminthopsis, Monocraterion, Phycodes, Planolites, Rosselia, Skolithos, Sustergichnus, Teichichnus, and Zoophycos. Zoophycos occurs abundantly only in sandstones containing phosphate pebble lags that represent a transgression, when dysaerobic bottom water may have temporarily encroached onto normally aerobic inner shelf facies. A Q-mode multidimensional scaling analysis of ichnogenera from Caldwell and Alta defines an environmental gradient. Tracefossil assemblages dominated by deposit-feeders in lower energy facies grade to ethologically diverse assemblages in higher energy facies. Low-energy facies are represented by shaly lithologies deposited in deeper water, or in shallow but protected environments.