Solving the woolly mammoth conundrum: amino acid 15N-enrichment suggests a distinct forage or habitat

Understanding woolly mammoth ecology is key to understanding Pleistocene community dynamics and evaluating the roles of human hunting and climate change in late Quaternary megafaunal extinctions. Previous isotopic studies of mammoths’ diet and physiology have been hampered by the ‘mammoth conundrum’: woolly mammoths have anomalously high collagen δ15N values, which are more similar to coeval carnivores than herbivores and which could imply a distinct diet and (or) habitat, or a physiological adaptation. We analyzed individual amino acids from collagen of adult woolly mammoths and coeval species and discovered greater  15N enrichment in source amino acids of woolly mammoths than in most other herbivores or carnivores. Woolly mammoths consumed an isotopically distinct food source, reflective of extreme aridity, dung fertilization and (or) plant selection. This dietary signal suggests that woolly mammoths occupied a distinct habitat or forage niche relative to other Pleistocene herbivores

Complex belemnites of the Puaroan (lower-? middle Tithonian) stage in the Port Waikato Region of New Zealand

Belemnite guards range through 2700 feet of Puaroan strata in the Port Waikato region. All are Belemnopsis of the uhligi-complex. Belemnopsis aucklandica aucklandica (Hochstetter) in its most typical form may be restricted to the lower 700 feet of the sequence. Three species are described, together with what may be transitional forms. The morphology of juvenile guards is in marked contrast with that of mature specimens, and development of the adult guard is revealed by examination of internal sections. Some aspects of belemnite paleoecology are discussed. Belemnite biostratigraphy of the area is outlined and the more important fossil localities are described

Mollusk species at a Pliocene shelf whale fall (Orciano Pisano, Tuscany)

The recovery of an intact, 10 m long fossil baleen whale from the Pliocene of Tuscany (Italy) offers the first opportunity to study the paleoecology of a fully developed, natural whale-fall community at outer shelf depth. Quantitative data on mollusk species from the whale fall have been compared with data from the sediments below and around the bones, representing the fauna living in the muddy bottom before and during the sinking of the carcass, but at a distance from it. Although the bulk of the fauna associated with the fossil bones is dominated by the same heterotrophs as found in the surrounding community, whale-fall samples are distinguishable primarily by the presence of chemosymbiotic bivalves and a greater species richness of carnivores and parasites. Large lucinid clams (Megaxinus incrassatus) and very rare small mussels (Idas sp.) testify to the occurrence of a sulphophilic stage, but specialized, chemosymbiotic vesicomyid clams common at deep-sea whale falls are absent. The whale-fall community is at the threshold between the nutrient-poor deep sea and the shallow-water shelf, where communities are shaped around photosynthetic trophic pathways and chemosymbiotic specialists are excluded by competition. © SEPM (Society for Sedimentary Geology)

Paleoecology of the Maastrichtian and Danian sediment at North of Central Alborz, Iran, based on Planktonic foraminifera

In order to study the fossil contents of the Ziarat-kola section for biostratigraphical purposes the 212 meters was sampled at Central Alborz. The sequence is mainly made up of monotonous grey- green to light grey marl. Based on Planktonic foraminifera age of Maastrichtian-Danian is determined to the section.

Four zones were determined by the benthic foraminifera morphogroup for showing oxygen and productivity change. The approximate low oxygen and high food supply has been indicates zone of one that increase infauna to epifauna morphotype percent is low (nearness 60% infouna, 40% epifauna). In zone two, with due attention to equal percent of Epifauna ratio to infauna, intermediate oxygen and food supply is anticipated. The decrasing epifauna foraminifera and increasing infauna demonstrates low oxygen and high food supply condition at zone of three. In zone four, increasing epifauna (approximate 90 percent) that are indicated high oxygen condition and low food supply. Analysis of planktonic foraminifera assemblage at this section with Cretaceous biostratigraphical provinces is indicating a close similarity with Tethyan provinces

Sedimentología y vertebrados fósiles de la Formación Santa Cruz (Mioceno temprano) en Lago Posadas, suroeste de Patagonia, Argentina

Lago Posadas se ubica al pie de los Andes Patagónicos Australes, en el suroeste de Argentina, donde la Formación Santa Cruz (FSC) del Mioceno temprano muestra afloramientos potentes y lateralmente continuos. Esta región ha sido escasamente explorada en relación con sus vertebrados fósiles desde los primeros esfuerzos de J.B. Hatcher en 1898-99. En esta contribución, se presentan estudios sedimentológicos y paleontológicos con el fin de reconstruir los ambientes deposicionales y la fauna de vertebrados asociada. Los datos sedimentológicos sugieren que el registro sedimentario comienza con depósitos marinos-estuarinos restringidos, que gradan a depósitos de planicies de inundación y canales fluviales. Dichas planicies, ocasionalmente interrumpidas por canales arenosos, muestran colores rojizos dominantes, pobre a moderado desarrollo de paleosuelos, abundantes depósitos de desbordes y ausencia de restos vegetales, lo cual sugiere depositación en ambientes oxigenados de bajo gradiente, con altas tasas de sedimentación. Las tendencias estratigráficas verticales son tenues, lo que indicaría cambios ambientales menores durante la depositación. Las direcciones de paleocorrientes, la composición de areniscas y la reconstrucción paleogeográfica indican que la acumulación de la FSC estuvo asociada al levantamiento Andino contemporáneo. Los vertebrados fósiles analizados son el resultado del esfuerzo propio de colecta y de colecciones de museos. La asociación faunística incluye 31 taxa: 28 mamíferos y tres aves. Los mamíferos pertenecen a los grupos principales registrados en otras áreas en la FSC (metaterios, xenartros, notoungulados, litopternos, astrapoterios y roedores) y permiten asignar una edad Santacrucense sensu lato a la fauna de la FSC de Lago Posadas. Son necesarias revisiones taxonómicas de varios taxa para mejorar el significado bioestratigráfico de esta asociación. La combinación del registro de arborícolas, ramoneadores y frugívoros por un lado, y mamíferos pastadores y ñandúes por el otro, plantearía la presencia tanto de árboles como de ambientes abiertos. Los frugívoros, entre los consumidores primarios, y el nicho de los consumidores secundarios, se encuentran subrepresentados debido a sesgos en el tamaño de los fósiles como en el tamaño del muestreo. El registro sedimentológico y paleontológico de la FSC en Lago Posadas sugiere que el ascenso de los Andes Patagónicos Australes ha actuado como un control primario sobre la subsidencia y el aporte de sedimentos, y ha otorgado características distintivas a las localidades subandinas. Sin embargo, los cambios climáticos previamente postulados, están pobremente registrados en este estudio.Lago Posadas is located at the foot of the Southern Patagonian Andes, in southwestern Argentina, where the early Miocene Santa Cruz Formation (SCF) shows thick and laterally continuous exposures. This region has been scarcely explored for fossil vertebrates since the first efforts by J.B. Hatcher in 1898-99. In this contribution, we performed sedimentologic and paleontological studies in order to reconstruct depositional environments and the associated fossil vertebrate fauna. Sedimentologic data suggest that the sedimentary record begins with restricted marine-estuarine deposits grading upward to fluvial floodplains and fluvial channels. Extensive floodplains, occasionally interrupted by low-sinuosity, sand-dominated channels, show dominant reddish coloration, moderate to low paleosol development, abundant crevasse splay sandstones and lack of vegetal remains, suggesting deposition in a low gradient, oxygenated setting under elevated sedimentation rates. Vertical stratigraphic trends are subtle, suggesting little paleoenvironmental changes during deposition of the whole SCF in this region. Paleocurrent directions, sandstone composition and paleogeographic reconstructions all indicate that deposition of the SCF was strongly associated to the contemporaneous uplift of the Andes. Fossil vertebrates analyzed are the result of our collecting effort and revision of museum collections. The faunal assemblage includes 31 taxa: 28 mammals and three birds. Mammals belong to the main groups recorded in other areas of the SCF (metatherians, xenarthrans, notoungulates, litopterns, astrapotheres and rodents). The assemblage allows a Santacrucian Age sensu lato assignment for the fauna at Lago Posadas. Taxonomic revisions of several taxa are necessary to further adjust the biostratigraphic significance of this association. The combined record of arboreal, browser and frugivores, on one side, and grazer mammals and rheas, on the other, suggest the presence of both trees and open environments. Frugivores, among primary consumers, and the secondary consumers guild are under-represented due to sample and fossil remain size biases. The sedimentologic and paleontological record of the SCF in Lago Posadas suggests that the uplift of the Southern Patagonian Andes acted as a primary control on basin subsidence and sediment supply, providing a special signature for sub-andean localities. However, previously registered climatic changes are poorly recorded in this study.Fil: Cuitiño, José Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; ArgentinaFil: Vizcaíno, Sergio Fabián. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Bargo, María Susana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; ArgentinaFil: Aramendía, Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentin

Ecological succession of a Jurassic shallow-water ichthyosaur fall.

After the discovery of whale fall communities in modern oceans, it has been hypothesized that during the Mesozoic the carcasses of marine reptiles created similar habitats supporting long-lived and specialized animal communities. Here, we report a fully documented ichthyosaur fall community, from a Late Jurassic shelf setting, and reconstruct the ecological succession of its micro- and macrofauna. The early 'mobile-scavenger' and 'enrichment-opportunist' stages were not succeeded by a 'sulphophilic stage' characterized by chemosynthetic molluscs, but instead the bones were colonized by microbial mats that attracted echinoids and other mat-grazing invertebrates. Abundant cemented suspension feeders indicate a well-developed 'reef stage' with prolonged exposure and colonization of the bones prior to final burial, unlike in modern whale falls where organisms such as the ubiquitous bone-eating worm Osedax rapidly destroy the skeleton. Shallow-water ichthyosaur falls thus fulfilled similar ecological roles to shallow whale falls, and did not support specialized chemosynthetic communities

The first report of South American edrioasteroids and the paleoecology and ontogeny of rhenopyrgid echinoderms

A new species of rhenopyrgid edrioasteroid Rhenopyrgus piojoensis sp. nov. is described form the Silurian (Lower Lud− low) Los Espejos Formation in the Precordillera of Argentina. This species is the first reported edrioasteroid from South America. Rhenopyrgids are widely distributed in Ordovician through Devonian deposits of most continents. Numerous juvenile specimens show that the general bodyplan is organized early in ontogeny and that the pedenculate zone lengthens with age. Phylogenetic analysis shows that rhenopyrgids are more closely related to edrioasterid edrioasteroids such as edrioblastoids and cyathocystids than to pyrgocystid isorophids.Fil: Sumrall, Colin D.. University of Tennessee; Estados UnidosFil: Heredia, Susana Emma. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodríguez, Cecilia María. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mestre García, Ana Isabel. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Rectoprotomarssonella n. gen., a new agglutinated foraminiferal genus from the Upper Cretaceous of the Carpathian Flysch

The new agglutinated foraminiferal genus Rectoprotomarssonella n. gen. is characterized by its high trochospiral coiling with multiserial to uniserial chamber arrangement and solid, noncanaliculate wall with calcareous cement. This taxon shows close relationship to the Cretaceous genus Protomarssonella Desai and Banner, from which it differs in possessing a uniserial part. The type species is a stratigraphic indicator in Campanian to Maastrichtian deep-water sediments in the Western Tethys and North Atlantic