Component Of Fauna Research Articles

Spatial patterns in sub‐Arctic benthos: multiscale analysis reveals structural differences between community components

AbstractAn important goal for ecosystem‐based management is to protect marine habitats and their associated fauna. Understanding the spatial structure and interrelationships of benthic communities and their underlying environmental drivers, therefore, is of great importance. The benthic community off the sub‐Arctic Lofoten‐Vesterålen islands was studied on multiple spatial scales, using theMEM(Moran's eigenvector maps) framework to identify spatial structure in broadscale (hundreds of kilometers), mesoscale (20 km), and fine‐scale (1.5 km) epifaunal and infaunal communities. A combination of eigenvector‐based multivariate analyses and variation partitioning on multiple sets of explanatory variables was used to identify characteristic species and environmental drivers that have a high importance in structuring the communities. Community structure of both epifauna and infauna strongly reflected the boundary of warm Atlantic (>0.5°C) and cold Arctic water masses (<0.5°C), which coincides approximately with the 800‐m isobath in this region. Apart from this dominant broadscale determinant, epifauna and infauna displayed different spatial patterns and drivers. Both components differ significantly across local marine landscapes; however, this characterization is not sufficient for infauna, where additional sediment characteristics play an important role in structuring the community across all spatial scales. Within marine landscapes (mesoscale), epifauna displays a spatial structure that, for the most part, could not be attributed to any of the included environmental drivers. The case of the Lofoten‐Vesterålen region demonstrated that the used analysis is a valuable tool in spatial planning, as it allows for comparison of the relative importance of individual environmental drivers for the studied faunal components, without losing the information about spatial patterns associated with individual drivers.

Subtidal soft sediments of the Paranaguá Bay inlet: mapping habitats and species distribution at a landscape scale

ABSTRACT This study aimed to map habitats and species distribution in a benthoscape section of the Paranagua Bay inlet, Parana State, Southern Brazil. The degree of correspondence between maps independently generated through sidescan imagery and macrofauna and sediment samples was also evaluated. The study area had approximately 9km2 and was chosen considering both diverse landscape features and proximity to future port developments. Sampling was performed in 67 evenly distributed and unreplicated sites. Patterns related to backscatter intensity (high and low) and the presence or absence of bedforms were observed, as well as other large-scale features like sand waves and beach rock outcrops. Local sedimentary environments were represented in a mosaic used for comparisons with sedimentary and faunistic data. Cluster analysis using grain size data formed four groups with similar particle size distribution. A strong correspondence between habitats and grain size distribution was found in only one habitat class. Macrofauna around the deeper Poco Point region and the Mel Island shallower banks presented high species richness and number of individuals. These were considered habitats of high biological relevance. Regions with bedforms indicate higher rates of sand transport in which a few species can thrive. The navigation channel had the lowest number of species and individuals when compared to vicinal regions, indicating persistent impacts. The study evidenced local estuarine bottom heterogeneity and contributed to the understanding of local processes of both bottom sediments dynamics and their associate faunal components.

A noteworthy accumulation of disparid crinoids from the type Cincinnatian (Upper Ordovician) of southwestern Ohio, USA: implications for the palaeoecology and taphonomy of crinoid “logjam” assemblages

Crinoids are a common and well-studied faunal component of the Upper Ordovician (Katian; Edenian) Kope Formation in the greater Cincinnati Arch region, USA. However, a relatively fresh outcrop exposing the Southgate and McMicken members of the Kope Formation at Cleves, Hamilton County, southwestern Ohio, has yielded a crinoid specimen worthy of description and comment. The specimen is a “logjam” of numerous articulated columns of Iocrinus subcrassus displaying parallel alignment, reflecting the influence of storm-generated currents. Iocrinus is not typically found in such a state; the genera Ectenocrinus and Cincinnaticrinus are generally associated with “logjams” in the type Cincinnatian, making this an unusual occurrence. At least one of the columns has the coiled dististele of another, smaller I. subcrassus tightly wrapped around it. Although I. subcrassus is known to employ a coiled dististele as an attachment strategy, ramose bryozoans are generally utilised as substrates and tight coiling around larger I. subcrassus columns has not previously been reported. Preservation of coiled dististeles, in general, is a feature not previously documented in Cincinnatian crinoid “logjams.” This specimen illustrates that unusual, noteworthy and/or rare material representing relatively common organisms continue to be discovered even within extensively studied units in the type Cincinnatian.

Habitat heterogeneity and butterfly diversity of Kuldiha Wildlife Sanctuary, Odisha, India

The present communication aims to highlight the trend of distribution of butterfly species in and around the protected forest areas of Kuldiha Wildlife Sanctuary (KWS), characterized with habitat heterogeneity with respect to vegetational assemblages, soil profiles and water bodies in comparison to butterfly diversity in other parts of India and neighbouring country. Butterfly diversity and distribution along with the seasonal gradients across three landscape areas, viz., LSE1, LSE2 and LSE3 were recorded at Kuldiha, Odisha, India using line transect. The method has generated baseline information relating not only to diversity, but also synchronization with vegetative growth coupled with phenological periodicity, and habitat heterogeneity of this aesthetically celebrated faunal component in a tropical deciduous evergreen forest landscape. A total of 95 species belonging to 63 genera and 5 families was encountered throughout the whole study period (Winter, 2015 to Summer, 2018) excepting the monsoon months. Post monsoon lepidopteran assemblage pattern was quite different from that of the pre-monsoon. Maximum diversity was observed in the LSE2, i.e. Mixed forest type exposed to certain levels of anthropogenic interactions. Present studies are considerably contribute to the ecobiology of the studied flagship species in particular and as a step towards holistic conservation strategy of an ecopotential sanctuary in the tropical country, India in general.J. Biodivers. Conserv. Bioresour. Manag. 2018, 4(1): 93-104

Changing depositional environments reflected by foraminifera in a transgressive-regressive sequence of the Lower Cretaceous on Spitsbergen

The Boreal Valanginian to Barremian foraminiferal succession of the Rurikfjellet Formation in central Spitsbergen is applied to stratigraphic zonation, analyses of depositional conditions and developing a sequence stratigraphic model. The study is based on the Janusfjellet section where the formation is 204 m thick, and represents a depth range from upper bathyal to prodelta top. It contains a continuous benthic foraminiferal succession permitting distinction of five assemblage zones. The assemblages are almost entirely agglutinated and reflect calcium carbonate depletion, which appears as an overall feature of Mesozoic Boreal seas superimposed on other, but more local restricting factors such as salinity and food supply. Close taxonomic similarities within the Boreal Realm are revealed by comparison of the Janusfjellet foraminiferal faunas to those of other pan-Arctic sites. The lower half of the Janusfjellet section contains a significant faunal component comparable to modern bathyal faunas and Late Cretaceous to Paleogene flysch-type assemblages indicating upper bathyal to offshore shelf depths. In the upper half of the section increased diversities are created by enhanced food supply in middle shelf setting. This is succeeded by increasing deltaic impact leading to hyposaline environments reflected by low species diversities. Changing foraminiferal biofacies trends through the Janusfjellet section are portrayed in the framework of the third order transgressive–regressive Wimanfjellet Sequence. Its transgressive systems tract was deposited mainly at upper bathyal depths with maximum flooding surface in the lower (Valanginian) part of the Rurikfjellet Formation. The regressive systems tract reveals an upward shoaling succession from upper bathyal conditions, through marine shelf to hyposaline prodelta setting.

Microscopic species make the diversity: a checklist of marine flora and fauna around the Island of Sylt in the North Sea

Based on the past 150 years of research and ongoing time-series observations we give a comprehensive overview of marine species composition around the island of Sylt in the eastern North Sea. A total of 2758 species is listed according to the categories microplankton (591 species), zooplankton (137), nekton (118), benthic microflora (158), benthic macroflora (125), benthic micro-and meiofauna (1204), benthic macrofauna (509), birds and mammals (91), and neobiota (39). Plants account for a third of the species, most (85%) of them are microscopic Chromista. Among animals, 60% of the species are micro- and meiofauna though this faunal component is still insufficiently known. These figures are similar to records from the southern North Sea and therefore may by typical for temperate climate sedimentary coastal areas. A comparison with the total of marine species suggests that the small benthic fauna may be severely understudied over most of the world. Analysis of global change depends on sound baseline data and species inventories like this can assist in the detection of biodiversity changes. They emphasise rare species and the full range of local habitats while time-series measurements usually rely on a few selected habitats and biotic components to generate a very general picture of the state of an ecosystem.

New caviomorph rodents from the late Oligocene of Salla, Bolivia: taxonomic, chronological, and biogeographic implications for the Deseadan faunas of South America

Caviomorph rodents have been an important component of South American mammal faunas at least since the Oligocene. Those from the Deseadan South American Land Mammal Age (SALMA; late Oligocene) have been exhaustively studied because they are considered key to understanding the evolution of South American rodents. Deseadan faunas are widely distributed from northern Peru to central Patagonia, with those from Salla (Bolivia) and Cabeza Blanca (Argentinean Patagonia) being the most diverse. Recent studies of Deseadan rodents at some localities in high (Cabeza Blanca, Punta Nava, Scarritt Pocket) and low (Contamana) latitudes revealed greater taxonomic diversity. However, at middle latitudes, Salla has not received the same attention, despite being exceptional in terms of the abundance and high-quality preservation of specimens. The aim of this work is to report new caviomorph rodents from Salla, and to discuss their systematic and palaeobiogeographical implications in the context of the South American Deseadan caviomorph assemblages. We describe two new genera (†Lapazomys gen. nov. and †Cholamys gen. nov.) and five new species (†Migraveramus lavocati sp. nov., †Sallamys woodi sp. nov., †Lapazomys hartenbergeri sp. nov., †Protosteiromys pattersoni sp. nov. and †Cholamys tetralophodonta sp. nov.). These include the first erethizontids and the oldest Cavioidea sensu stricto for middle and low latitudes. The increase in the number of species corroborates the existence of an important rodent diversification already evidenced in the late early/early late Oligocene. In addition, the new rodents lessen the degree of endemism of the Salla rodent fauna proposed in previous papers. We interpret that the differences among Deseadan assemblages from low, middle and high latitudes are due essentially to climatic, historical and local environmental conditions, whereas diachronism seems less important in the modelling of faunas.http://zoobank.org/urn:lsid:zoobank.org:pub:A8A04332-12E1-4966-9807-47B66554718E

The bat-bird-bug battle: daily flight activity of insects and their predators over a rice field revealed by high-resolution Scheimpflug Lidar.

We present the results of, to our knowledge, the first Lidar study applied to continuous and simultaneous monitoring of aerial insects, bats and birds. It illustrates how common patterns of flight activity, e.g. insect swarming around twilight, depend on predation risk and other constraints acting on the faunal components. Flight activity was monitored over a rice field in China during one week in July 2016, using a high-resolution Scheimpflug Lidar system. The monitored Lidar transect was about 520 m long and covered approximately 2.5 m3. The observed biomass spectrum was bimodal, and targets were separated into insects and vertebrates in a categorization supported by visual observations. Peak flight activity occurred at dusk and dawn, with a 37 min time difference between the bat and insect peaks. Hence, bats started to feed in declining insect activity after dusk and stopped before the rise in activity before dawn. A similar time difference between insects and birds may have occurred, but it was not obvious, perhaps because birds were relatively scarce. Our observations are consistent with the hypothesis that flight activity of bats is constrained by predation in bright light, and that crepuscular insects exploit this constraint by swarming near to sunset/sunrise to minimize predation from bats.

Diversification rates indicate an early role of adaptive radiations at the origin of modern echinoid fauna.

Evolutionary radiations are fascinating phenomena corresponding to a dramatic diversification of taxa and a burst of cladogenesis over short periods of time. Most evolutionary radiations have long been regarded as adaptive but this has seldom been demonstrated with large-scale comparative datasets including fossil data. Originating in the Early Jurassic, irregular echinoids are emblematic of the spectacular diversification of mobile marine faunas during the Mesozoic Marine Revolution. They diversified as they colonized various habitats, and now constitute the main component of echinoid fauna in modern seas. The evolutionary radiation of irregular echinoids has long been considered as adaptive but this hypothesis has never been tested. In the present work we analyze the evolution of echinoid species richness and morphological disparity over 37 million years based on an extensive fossil dataset. Our results demonstrate that morphological and functional diversifications in certain clades of irregular echinoids were exceptionally high compared to other clades and that they were associated with the evolution of new modes of life and so can be defined as adaptive radiations. The role played by ecological opportunities in the diversification of these clades was critical, with the evolution of the infaunal mode of life promoting the adaptive radiation of irregular echinoids.

Influence of sediment characteristics on density and distribution of Ocypodoid crab burrows (superfamily: Ocypodoidea) along the coastal areas of Pakistan

Crabs belong to the superfamily Ocypodoidea are a significant component of benthic fauna and considered as ecosystem engineers because of their dynamic role as an active burrower in mangrove and estuarine environment. The current investigation was to evaluate the crab burrow density, diameter and total area of burrow opening along the coast of Pakistan. The variations in burrow properties and their relation to sediment characteristics were also evaluated to recognize the most influencing variables of sediments that effects on crab burrows. All crab burrow and sediment characteristics differed significantly (p<0.05) among the monitoring sites. Regression analysis showed that crab density was significantly correlated with burrow density (P<0.001). Moreover, burrow density was noticed significantly greater (p<0.05) than crab density. Pearson correlation analysis reveals that moisture, porosity, organics, sand and mean grain size observed as most influencing the features of sediment to determine the ecological functioning of crab burrows in mangrove and mudflats of Pakistan.

Archival sea turtles in National Zoological Collections of Zoological Survey of India

The archival zoological collections are the foundation of taxonomic nomenclature and systematics research. Name-bearing zoological collection of a species or subspecies and their comparative data often resolved many ambiguities in systematics, distribution patterns and other biological information. In this study, we revisited the sea turtles collections available at Zoological Survey of India and Indian Museum Gallery. The aimed study may reconcile the previous and present range distribution of this oldest faunal component in Indian waters. The detailed collateral data of the studied species would substantiate to know the actual range distribution, estimate the anthropogenic threats, and effect of climate change in estuarine eco-system, which helps in better conservation strategies.

Genealogical and niche modeling analyses reveal recent expansion and limited genetic divergence in the Formicivora serrana complex (Passeriformes: Thamnophilidae)

The principal aim of this study was to infer the phylogeographic pattern of the antwrens of the Formicivora serrana complex, an endemic faunal component of the semi-deciduous forests and restinga formations of the Atlantic Forest of southeast Brazil. We combined niche-based modeling and phylogeographic approaches in describing the genetic spatial structure of the taxon, inferring the phylogenetic hypothesis of lineage diversification, and providing estimates of population growth, timing of coalescence, and gene flow. We also modeled the species potential distribution to examine the putative consequences of the Last Glacial Maximum (LGM) (21,000 years ago) and Holocene climate variability. To perform this, we analyzed a dataset composed of two mitochondrial (cytochrome oxidase I and NADH dehydrogenase subunit 2) and four nuclear (anonymous loci) DNA regions from 35 specimens. Genealogical analyses were performed using phylogenetic maximum likelihood and coalescent Bayesian approaches; genetic diversity was assessed using analysis of molecular variance and network analysis; ages of coalescent events were estimated using a relaxed molecular clock model. Ecological niche modeling of current and LGM ranges were performed using six algorithms (Bioclim, general additive model, general linear model, Maxent, support vector machine and Random forest) based on 178 occurrence localities and 19 bioclimatic variables. Limited genetic divergence among recognized forms of the F. serrana complex was evidenced in the low mitochondrial nucleotide divergence among populations (Jukes–Cantor distance between subspecies varied from 0.17 to 0.21%), unresolved phylogenetic trees, star-shaped haplotype networks, and overall lack of population genetic structure. Fixation index analyses, however, suggested an incipient geographic structure. Ecological niche modeling suggested expansion of the distribution range since the LGM. Our results provide the first evidence that bird taxa of xerophytic and semi-deciduous habitats of the AF were also affected by Quaternary climatic fluctuations. The recovered genealogical pattern indicates that F. serrana should be regarded as a single evolutionary unit, corroborating current taxonomic hypotheses.

Extensión del rango de la paloma cabeza ploma (Leptotila plumbeiceps) en la Reserva de la Biosfera Sierra Gorda de Guanajuato, México

Registramos por primera vez a la paloma cabeza ploma (Leptotila plumbeiceps) en la Reserva de la Biosfera Sierra Gorda de Guanajuato (RBSGG), estado de Guanajuato. Entre septiembre y octubre de 2016 obtuvimos fotografías de individuos de esta especie en los márgenes del río Manzanares, en el municipio de Victoria, Guanajuato. La notoriedad de nuestro registro radica en que la presencia de dicha especie en la RBSGG reafirma la existencia de un componente faunístico tropical a subtropical asociado a los ríos Manzanares y Santa María, que está presente en el área de transición del Altiplano Mexicano y la Sierra Madre Oriental situada en la reserva.

Potential contribution of surface-dwelling Sargassum algae to deep-sea ecosystems in the southern North Atlantic

Deep-sea ecosystems, limited by their inability to use primary production as a source of carbon, rely on other sources to maintain life. Sedimentation of organic carbon into the deep sea has been previously studied, however, the high biomass of sedimented Sargassum algae discovered during the VEMA Transit expedition in 2014/2015 to the southern North Atlantic, and its potential as a regular carbon input, has been an underestimated phenomenon. To determine the potential for this carbon flux, a literature survey of previous studies that estimated the abundance of surface water Sargassum was conducted. We compared these estimates with quantitative analyses of sedimented Sargassum appearing on photos taken with an autonomous underwater vehicle (AUV) directly above the abyssal sediment during the expedition. Organismal communities associated to Sargassum fluitans from surface waters were investigated and Sargassum samples collected from surface waters and the deep sea were biochemically analyzed (fatty acids, stable isotopes, C:N ratios) to determine degradation potential and the trophic significance within deep-sea communities. The estimated Sargassum biomass (fresh weight) in the deep sea (0.07–3.75g/m2) was several times higher than that estimated from surface waters in the North Atlantic (0.024–0.84g/m2). Biochemical analysis showed degradation of Sargassum occurring during sedimentation or in the deep sea, however, fatty acid and stable isotope analysis did not indicate direct trophic interactions between the algae and benthic organisms. Thus, it is assumed that components of the deep-sea microbial food web form an important link between the macroalgae and larger benthic organisms. Evaluation of the epifauna showed a diverse nano- micro-, meio, and macrofauna on surface Sargassum and maybe transported across the Atlantic, but we had no evidence for a vertical exchange of fauna components. The large-scale sedimentation of Sargassum forms an important trophic link between surface and benthic production and has to be further considered in the future as a regular carbon input to the deep-sea floor in the North Atlantic.

Blood-sucking ticks (Acarina, Ixodoidea) as an essential component of the urban environment

The problem of urban ticks has arisen from the increased rate of urbanization since WWII. Expansion of municipal boundaries encompasses adjacent territories, so that large areas of wilderness together with all their inhabitants get incorporated into city limits. Current strategies of biodiversity conservation include the creation of green corridors and other forms of connectivity between wilderness and urban areas as well as between green patches within cities. All this allows various mammals and birds to migrate from their native habitats into and between various parts of the cities and to establish permanent urban populations. Medium-sized and larger animals provide adult ticks with blood meal, thus creating suitable conditions for the establishment and persistence of tick populations. Independent tick populations can exist in urban forests, parks, private properties, old cemeteries, etc. Over the last decades, the tick populations that originated from those in natural habitats around the cities have become a permanent component of urban fauna. Among such ticks, the castor bean tick Ixodes ricinus is the most important species for European cities, while the deer tick I. scapularis is of great significance for the East Coast of the United States. The taiga tick I. persulcatus is the most important species for the Russian cities and towns within its range. All these and some other ticks aggressively attack humans and their pets inside cities. The tick species especially well adapted to urban life are those which can live and reproduce in buildings. The brown dog tick Rhipicephalus sanguineus (family Ixodidae), the pigeon ticks from the reflexus group of the genus Argas, and Ornithodoros ticks (family Argasidae), which form urban and semi-urban populations, are the main urban tick pests and vectors. House infestation by ticks can lead to human infection with tick-borne pathogens or severe allergic reactions. Some tick hosts, mammals as well as birds, maintain tick-transmitted pathogens and serve as competent reservoir hosts. Urban populations of these animals can participate in the circulation of some pathogens within cities. Thus, the enlargement of urban green areas followed by their population by wild mammals and birds create good opportunities for the establishment of urban populations of tick vectors with the resulting threat to the health of urban dwellers and their pets. At the same time, our understanding of the real scope and complexity of the problem of urban ticks is far from being sufficient. Finding the ways of protecting the environment without increasing the risk to human health in modern cities is a pressing and challenging problem of our time.

The Tule Springs local fauna: Rancholabrean vertebrates from the Las Vegas Formation, Nevada

A middle to late Pleistocene sedimentary sequence in the upper Las Vegas Wash, north of Las Vegas, Nevada, has yielded the largest open-site Rancholabrean vertebrate fossil assemblage in the southern Great Basin and Mojave Deserts. Recent paleontologic field studies have led to the discovery of hundreds of fossil localities and specimens, greatly extending the geographic and temporal footprint of original investigations in the early 1960s. The significance of the deposits and their entombed fossils led to the preservation of 22,650 acres of the upper Las Vegas Wash as Tule Springs Fossil Beds National Monument. These discoveries also warrant designation of the assemblage as a local fauna, named for the site of the original paleontologic studies at Tule Springs.The large mammal component of the Tule Springs local fauna is dominated by remains of Mammuthus columbi as well as Camelops hesternus, along with less common remains of Equus (including E. scotti) and Bison. Large carnivorans including Canis dirus, Smilodon fatalis, and Panthera atrox are also recorded. Micromammals, amphibians, lizards, snakes, birds, invertebrates, plant macrofossils, and pollen also occur in the deposits and provide important and complementary paleoenvironmental information. The fauna occurs within the Las Vegas Formation, an extensive and stratigraphically complex sequence of groundwater discharge deposits that represent a mosaic of desert wetland environments. Radiometric and luminescence dating indicates the sequence spans the last ∼570 ka, and records hydrologic changes in a dynamic and temporally congruent response to northern hemispheric abrupt climatic oscillations. The vertebrate fauna occurs in multiple stratigraphic horizons in this sequence, with ages of the fossils spanning from ∼100 to ∼12.5 ka.

Clam shrimp genus Ordosestheria from the Lower Cretaceous Dalazi Formation in Jilin Province, north-eastern China

Ordosestheria Wang, 1984 was originally described from the lower Aptian Jingchuan Formation (previously the sixth member of the Zhidan Group) in north-western China. It was recovered from the lower Barremian Bouhedma Formation in southern Tunisia. However, we identified species of Ordosestheria from the upper Albian Dalazi Formation in north-eastern China, which were previously identified as orthestheriids. This means that the distribution area of Ordosestheria is wider than we thought before. Through the SEM examination of specimens of Or. multicostata (Chen in Zhang et al., 1976), new features have been discerned: 1) small-sized polygonal reticulation occurs on growth bands near the umbo; 2) reticulation changes into evenly distributed puncta; 3) then widely spaced radial lirae with intercalated fine puncta; 4) puncta are disappeared on middle and lower part of the carapace, leaving an undulating upper part and a row of small pits along the lower margin of each growth band; 5) growth lines are serrated in their lower margins. As a result, Ordosestheria is also a principal component of the Yanjiestheria clam shrimp fauna, and can be an index genus for the subdivision of non-marine sequences in China.

New explanation for elements of Hainan Island's biological assemblage may stretch things a little too far

Recent interpretations of various floral and faunal components on Hainan Island and the nearby parts of mainland east Asia invoke a mid‐Cenozoic plate‐tectonic rifting episode that displaced the landmass ca 220 km south‐eastwards from a postulated former site directly adjacent to the China– Vietnam border. However, having sifted through the relevant geological evidence I contend that this idea is weakly founded. In explaining challenging biogeographical patterns, it is suggested that all of the geo‐physical processes that could have forged the distributions need to be considered.

Vertebrate paleontology, stratigraphy, and paleohydrology of Tule Springs Fossil Beds National Monument, Nevada (USA)

Tule Springs Fossil Beds National Monument (TUSK) preserves 22,650 acres of the upper Las Vegas Wash in the northern Las Vegas Valley (Nevada, USA). TUSK is home to extensive and stratigraphically complex groundwater discharge (GWD) deposits, called the Las Vegas Formation, which represent springs and desert wetlands that covered much of the valley during the late Quaternary. The GWD deposits record hydrologic changes that occurred here in a dynamic and temporally congruent response to abrupt climatic oscillations over the last ~300 ka (thousands of years). The deposits also entomb the Tule Springs Local Fauna (TSLF), one of the most significant late Pleistocene (Rancholabrean) vertebrate assemblages in the American Southwest. The TSLF is both prolific and diverse, and includes a large mammal assemblage dominated by Mammuthus columbi and Camelops hesternus. Two (and possibly three) distinct species of Equus, two species of Bison, Panthera atrox, Smilodon fatalis, Canis dirus, Megalonyx jeffersonii, and Nothrotheriops shastensis are also present, and newly recognized faunal components include micromammals, amphibians, snakes, and birds. Invertebrates, plant macrofossils, and pollen also occur in the deposits and provide important and complementary paleoenvironmental information. This field compendium highlights the faunal assemblage in the classic stratigraphic sequences of the Las Vegas Formation within TUSK, emphasizes the significant hydrologic changes that occurred in the area during the recent geologic past, and examines the subsequent and repeated effect of rapid climate change on the local desert wetland ecosystem.

Carnivoran resource and habitat use in the context of a Late Miocene faunal turnover episode

AbstractWe investigate resource and habitat use by apex predators through stable isotope analysis at two Spanish Late Miocene localities: Los Valles de Fuentidueña (~9.6 Ma, LVF) and Cerro de los Batallones (~9.1 Ma, BAT). The temporal window represented by LVF and BAT was crucial in the shaping of the current Iberian mammalian structure because it corresponds to the initial stages of a faunal turnover episode and regional environmental change at ~9.5–8.5 Ma (Vallesian–Turolian transition), associated with an increase in the seasonality of precipitation. Herbivore and carnivore δ13C and δ18O values do not point to significant changes in either the vegetation cover (a woodland to mesic C3 grassland) or the hydrological regime during the time lapse represented between LVF and BAT. This suggests that the environmental shift recorded around the Vallesian–Turolian boundary may have occurred later in time, since LVF and BAT ages are synchronic with the onset of the turnover event. From the standpoint of predator–prey evaluation by means of stable isotope analysis, statistical post hoc tests, mixing model output, and the assessment of niche occupation by LVF and BAT carnivores point to high levels of interspecific competition among large active carnivores, albeit some genera, such as the amphicyonid Magericyon and specially the hyaenid Lycyaena, seemed to avoid competition by taking prey from a more open habitat. Despite the drop in diversity and change in faunal components observed between the LVF and BAT assemblages, a high degree of resource and habitat competition is evident from stable isotope data.