Mammal Assemblages Research Articles

Assessing the reliability of raptor pellets in recording local small mammal diversity

AbstractUnderstanding how raptors select prey is important to determine taphonomic biases both in modern and paleo pellet assemblages. We tested whether pellets more closely represent raptor dietary specialization or local small mammal diversity by sampling pellets from seven raptor species across four study sites in Yellowstone National Park, Wyoming, USA. We identified small mammal craniodental elements from each pellet and tested for differences among small mammal assemblages for each raptor species and study site. We found that reconstructed avian predator diets clustered significantly by site but not by predator species. Bray-Curtis diet dissimilarities were also significantly lower when comparing different raptor species within a site than when comparing the same raptor species across different sites. Our results suggest that raptors choose to eat a diversity of small mammal species close to their roosts rather than fly long distances to specialize on a particular prey species. Neontologists and paleoecologists alike can therefore be confident that raptor pellets faithfully represent local small mammal diversity.

Small mammal assemblages and their ectoparasite prevalence (Acarina) in mangrove forests of Peninsular Malaysia

The mangrove forest is located in the coastal intertidal zone and plays a vital role in buffering against erosion from storm surges, currents, waves, and tides. This ecosystem also serves for ecotourism due to its heterogeneous habitats, which supported a high diversity of plants and animals. Small mammals are among the abundant but poorly recognised inhabitants in mangrove forests. Apart from their role as primary consumer and prey, they are host to various ectoparasites, which potentially become the primary vector for tick-borne diseases among visitors. Therefore, this study aims to determine the small mammal assemblages and their ectoparasite prevalence in mangroves forests of Peninsular Malaysia. The capture-release method was applied for small mammal sampling, and each captured individual was screened and collected for ectoparasites before released. DNA barcoding using CO1 genes was performed for small mammal species verification, whereby ectoparasite identification was based on morphological identification and molecular verification using 16S rDNA genes. A total of 94 small mammals from 6 species were captured across sites, dominated by Rattus tiomanicus (n=74). From this number, 15 individuals (16% prevalence) were infested by ticks, 22 individuals (23%) were infested by mites, whereas 4 individuals (4%) were infested by both ticks and mites. Five species of ticks and one mite species were identified; Amblyomma cordiferum, Ixodes granulatus, Haemaphysalis hystricis, Dermacentor auratus, Dermacentor atrosignatus, and Laelaps echidninus. This study reveals a relatively poor diversity of small mammals in the mangroves forest, of which highly infested with a diversity of ectoparasites, elucidating the relationship of hostectoparasite associations in the riparian zone. This information is crucial to inform visitors to these areas, ultimately safeguard against ectoparasite-borne disease.

Medium-sized and large mammals of the Floresta da Cicuta Area of Relevant Ecological Interest, a protected area in southeastern Brazil

The Atlantic Forest is one of the most biodiverse biomes in the world and has been severely degraded and fragmented, with the extirpation of most medium-sized and large vertebrates from the forest remnants. Here we present the results of a survey of medium-sized and large mammals in an area of protected seasonal semideciduous forest, the Floresta da Cicuta Area of Relevant Ecological Interest (ARIE-FC), Rio de Janeiro, Brazil, part the Atlantic Forest biome. We used camera traps (2,257 camera days) and direct observations over a 23-month period. We recorded 19 species (including two domestic species), seven of which are classified as at-risk, such as Leopardus guttulus (Hensel, 1872), Sylvilagus tapetillus Thomas, 1913, Alouatta clamitans Cabrera, 1940, and Chrysocyon brachyurus (Illiger, 1815). A diverse terrestrial mammal assemblage in the ARIE-FC reinforces the importance of small forest fragments for the conservation of biodiversity in human-modified landscapes of the Brazilian Atlantic Forest.

The fossil vertebrates of Guatemala

The fossil vertebrates of Guatemala are almost exclusively fossils of mammals and are of late Miocene (Hemphillian) and late Pleistocene (Rancholabrean) age. The only lower vertebrates are the crocodile fossil Crocodilus moreletti collected in the Río La Pasión area, a turtle from El Trifinio and fishes from Río Carboneras. The late Miocene mammals are the proboscidean Gomphotherium, an aceratheriine rhinoceros and the horse Neohipparion from the Río Carboneras in Izabal; the holotype of “Serridentinus guatemalensis” (nomen dubium) from Chinautla in the Department of Guatemala is also a specimen of Gomphotherium of likely late Miocene age. Late Pleistocene vertebrates are known from at least 36 localities in Guatemala, but only six of these yield at least four documented genera of mammals—Chivacabé, Ciudad Real. El Rosario, Estanzuela, Río La Pasión and San Rafaelito. The combined list of Guatemalan late Pleistocene mammal genera is Canis, Cuvieronius, Dicotyles, Equus, Eremotherium, Euceratherium, Glyptotherium, Holmesina, Mammuthus, Mazama, Megalonyx, Mixotoxodon, Neochoerus, Odocoileus, Pachyarmatherium, Palaeolama, Paramylodon, and Tapirus. The late Pleistocene mammals from Guatemala resemble broadly correlative mammal assemblages from throughout Central America in being dominated by the fragmentary remains of large herbivorous mammals and in having a mixture of immigrants from both North and South America. They thus well reflect a substantial taphonomic megabias in the Central American Pleistocene mammal record towards large mammals with large and durable skeletal parts that are easily preserved and readily discovered. This megabias renders problematic direct biological inferences from the Guatemalan Pleistocene mammal record. Mammoth records from Guatemala are relatively numerous for a Central American country but so few that inferring extensive grasslands or positing migration routs of mammoths from these records are questionable. There is no demonstrable association of humans with extinct Pleistocene megamammals in Guatemala despite claims to the contrary. The suggestion that during the late Pleistocene Guatemala was north of a biogeographic juncture between North and South America lacks any support. The Guatemalan fossil vertebrate record needs extensive augmentation, with an appropriate stratigraphic context, especially of lower vertebrates and micromammals, to provide further insight into vertebrate history in Central America during the last 10 million years.

Short Communication: Proportion faunal assemblages of carnivorous mammals in geoecological districts of Mordovia, Russia

Abstract. Andreychev A. 2021. Short Communication: Proportion faunal assemblages of carnivorous mammals in geoecological districts of Mordovia, Russia. Biodiversitas 22: 4625-4632. In the forest-steppe area, carnivorous mammals are represented by species of different faunistic assemblages. This circumstance makes the study region a priority since the species of which faunistic assemblages prevail is of interest. Fifteen carnivorous species have been identified in the territory of Mordovia. Among them, the family Mustelidae predominates in terms of the number of species. The species are found in all geoecological districts, but their distribution is uneven. The most notable species in the region are located in coniferous and broad-leaved forests (40%) and species widely distributed in several natural areas (40%). 13% of the total number of noted species belong to the taiga fauna types. The steppe type of fauna is represented by only 7% of the total number of recorded species. For each geoecological region, the fauna features are given, and a list of rare and exciting species is given. The forest-steppe zone to which Mordovia belongs is compared by the fauna of carnivorous mammals with other regions from three typical faunal assemblages.

Camera-trap data do not indicate scaling of diel activity and cathemerality with body mass in an East African mammal assemblage.

Diel activity patterns of animal species reflect constraints imposed by morphological, physiological, and behavioral trade‐offs, but these trade‐offs are rarely quantified for multispecies assemblages. Based on a systematic year‐long camera‐trap study in the species‐rich mammal assemblage of Lake Manyara National Park (Tanzania), we estimated activity levels (hours active per day) and circadian rhythms of 17 herbivore and 11 faunivore species to determine the effects of body mass and trophic level on activity levels and cathemerality (the degree to which species are active throughout the day and night). Using generalized least squares and phylogenetic generalized least squares analyses, we found no support for the hypothesis that trophic level is positively associated with activity levels. We found no support for activity levels to scale positively with body mass in herbivores or to differ between ruminants and nonruminants; in faunivores, we also did not detect relationships between body mass and activity levels. Cathemerality was positively associated with activity levels but did not scale significantly with body mass. Overall, our findings caution against trophic level or body mass‐associated generalized conclusions with regard to diel activity patterns.

The Miocene fossil lizards from Kutch (Gujarat), India: a rare window to the past diversity of this subcontinent

AbstractThe Miocene beds of Kutch in India are well known for their mammalian assemblages, including the extinct ape Sivapithecus, but far less is known about the fossil squamates from this area. Although India with its over 800 reptile species is recognized as one of the global biodiversity hotspots, knowledge of past diversity and paleobiogeography of squamates on this subcontinent is very limited. We here report on new lizard finds, which have been recovered from two stratigraphic levels: the older Palasava locality (dated to the middle Miocene, ca. 14 Ma) and the younger Tapar site (late Miocene, ca. 11–10 Ma). Although fragmentarily preserved, the material described here sheds important light on the composition and paleobiogeography of squamates during the Miocene in South Asia. The older Palasava locality contains cf. Uromastyx s.l. and Varanus sp., the latter representing the oldest record of this taxon in the region of India south of the Himalayas and its occurrence here suggests a mean annual temperature not less than 15°C. The material from the younger Tapar locality consists of an unidentified acrodontan lizard, here questionably placed in agamids, and a skink. The latter shows a resemblance to mabuyines, however, the fragmentary nature of the material does not allow a precise allocation without doubts. The cosmopolitan mabuyines have been suggested to have their origin in Asia, so the potential presence of mabuyines in the Tapar locality might represent the first, but putative, Asian evidence of the occurrence of this group in the Miocene.

Anthropogenic perturbation modifies interactions between mammals and fruits in a tropical forest of southern Mexico

Abstract Studies of tropical mammal defaunation highlight the loss of species as well as their reduction in abundance and diversity; however, there is a complex series of effects associated with this anthropogenic disruption, including increases in the relative abundance of disturbance-tolerant mammals and the arrival of alien mammals whose effects on biotic interactions have been poorly studied. We compared the species richness, composition, interaction strength, and patterns of daily activity of mammals that consume the fruits of Pouteria sapota on the forest floor, both inside and outside of the Los Tuxtlas Field Station (LTFS) in Veracruz, southern Mexico. Using camera traps, we recorded eight mammal species interacting with the fruits inside the LTFS ( trees) and nine species interacting outside ( trees). Alien species such as Canis lupus familiaris were recorded both inside and outside of the LTFS, whereas Bos taurus was only recorded outside. Medium-sized generalist mammals were overrepresented both inside and outside of the LTFS, evidencing an impoverishment of the fauna, when compared to the mammal assemblage reported to interact with P. sapota fruits in a more intact forest. The daily activity patterns of the mammals that interacted strongly with P. sapota fruits were different inside and outside the LTFS, particularly in the case of Cuniculus paca. Our results show that the impact of human activity is highly pervasive, directly affecting the mammalian fauna at different levels and indirectly affecting the biotic interactions in which these animals are involved.

Late early Miocene mammals from Laguna del Laja, Cura-Mallín Formation, south-central Chile (~37°S) and their biogeographical and paleoenvironmental significance

Despite recent efforts, the diversity of Neogene mammals in Chile remains poorly known, with several presumed new taxa awaiting description. For example, previous studies have suggested that the early to late Miocene mammalian assemblages from the Laguna del Laja fossiliferous locality (Cura-Mallín and Trapa-Trapa formations), in the Andean Cordillera of south-central Chile (~37°), comprise dozens of undescribed taxa. Therefore, a better understanding of the Laguna del Laja faunal taxonomic affinities is needed, especially because the region holds one of the few known localities spanning from early to late Miocene in Chile. Dozens of mammal specimens recently recovered in late early Miocene beds of the Cura-Mallín Formation at Laguna del Laja are described and illustrated, and a discussion of their biogeographical and paleoenvironmental significance is provided. We recognize the presence of at least 17 taxa, including some potential new ones (e.g., Maruchito sp. nov.?) and others recognized in Chile for the first time (e.g., Galileomys). Geochronological (17.7–16.4 Ma) and biostratigraphical data indicate that this fauna correlates well with the Santacrucian SALMA, contributing to filling the gap in the taxonomic composition of Santacrucian mammalian assemblages in Chile and southwestern of South America. However, it is noteworthy that Laguna del Laja has documented some taxa previously found only in older (Colhuehuapian) and younger (Colloncuran) ages. Finally, the faunal assemblage supports a paleoenvironmental reconstruction of mixed forested and open habitats, likely with the predominance of the former, in the region during the late early Miocene and a widely distributed Santacrucian fauna throughout southern South America in both intra-arc and foreland basins.

Testing the effects of ecologically extinct mammals on vegetation in arid Australia: A long‐term experimental approach

AbstractThe loss of species from ecosystems can have cascading impacts on species interactions and ecosystem function. Australia has experienced the greatest loss of mammals globally in the past 200 years, but we know little of how the loss of this suite of ecosystem engineers and herbivores has affected vegetation. We used a threatened mammal reintroduction sanctuary to investigate effects of ecologically extinct mammals on plant assemblages. First, we tested the net effects of mammals using a long‐term exclusion experiment within the sanctuary. Second, we used a three‐year disturbance experiment to determine the relative roles of herbivory and physical disturbance in driving changes in plant assemblages. Third, we compared outcomes inside and outside the sanctuary to determine how effects of reintroduced mammals differed from contemporary mammal assemblages. Plant species richness was greatest in mammal exclusion plots and declined across all treatments from 2011 to 2018, probably due to drought. Plant composition changed in response to mammal exclusion, with six species increasing significantly, shrubs and myrmecochorous plants becoming more common and large‐seeded species less common. Responses to experimental disturbance were less clear. Grass and resprouters were more common, and palatable and large‐seeded plants were less common outside the sanctuary (exposed to contemporary mammal assemblage). Our study shows that reintroductions of ecologically extinct mammals have substantial impacts on plant assemblages, both through ecosystem engineering and herbivory, and these impacts differ from those of contemporary mammal faunas, suggesting that pre‐European Australian ecosystems were markedly different from contemporary ecosystems.

Mammal assemblage composition predicts global patterns in emerging infectious disease risk

As a source of emerging infectious diseases, wildlife assemblages (and related spatial patterns) must be quantitatively assessed to help identify high‐risk locations. Previous assessments have largely focussed on the distributions of individual species; however, transmission dynamics are expected to depend on assemblage composition. Moreover, disease–diversity relationships have mainly been studied in the context of species loss, but assemblage composition and disease risk (e.g. infection prevalence in wildlife assemblages) can change without extinction. Based on the predicted distributions and abundances of 4466 mammal species, we estimated global patterns of disease risk through the calculation of the community‐level basic reproductive ratio R0, an index of invasion potential, persistence, and maximum prevalence of a pathogen in a wildlife assemblage. For density‐dependent diseases, we found that, in addition to tropical areas which are commonly viewed as infectious disease hotspots, northern temperate latitudes included high‐risk areas. We also forecasted the effects of climate change and habitat loss from 2015 to 2035. Over this period, many local assemblages showed no net loss of species richness, but the assemblage composition (i.e. the mix of species and their abundances) changed considerably. Simultaneously, most areas experienced a decreased risk of density‐dependent diseases but an increased risk of frequency‐dependent diseases. We further explored the factors driving these changes in disease risk. Our results suggest that biodiversity and changes therein jointly influence disease risk. Understanding these changes and their drivers and ultimately identifying emerging infectious disease hotspots can help health officials prioritize resource distribution.

Niche partitioning in small mammals: interspecific and biome-level analyses using stable isotopes

Abstract Small mammal assemblages from South America provide a unique opportunity to measure coexistence and niche partitioning between marsupials and placentals. We tested how these two major clades partition environmental resources by comparing stable isotopic ratios of similar sized Didelphidae and Sigmodontinae in four Brazilian biomes: Pampas grassland, Pantanal wetland, Cerrado woodland savanna, and Atlantic Forest. Generally, didelphid isotopic niche follows a scaling law, because we found an association between δ15N enrichment and body mass. Sigmodontines that primarily partition the environment via forest strata showed a greater intake of C4 or/and crassulacean acid metabolism (CAM) plants than didelphids, as reflected by their wider trophic niche. Values of δ13C were highest in savannas and grasslands (Cerrado and Pampas biomes), and values of δ15N were highest in the Atlantic Forest (in sigmodontines) and Pampas (in didelphids). While assessing patterns between the two major Brazilian biomes (Atlantic Forest and Cerrado), we found evidence of a broader trophic niche for both clades in the Cerrado. In the Atlantic Forest, niche occupation by Didelphidae was completely enclosed within the Sigmodontinae trophic niche. Both clades showed less overlap in the Cerrado, a less productive environment. Our results highlight the importance of a comparative framework and the use of stable isotopes for testing ecological questions related to how small mammalian communities partition their niche.

Effects of camera‐trap placement and number on detection of members of a mammalian assemblage

AbstractA central goal in camera‐trapping (CT) studies is to maximize detection probability and precision of occupancy estimates while minimizing the number of CTs to reduce equipment and labor costs. Few studies, however, have examined the effect of CT number on detection probability. Moreover, historically, most studies focused on a specific species and the design could be tailored toward maximizing detection of this target species. Increasingly, however, such studies use data for all captured, non‐target, species (by‐catch data) for animal community‐level analyses. It remains unclear if, and how, the targeting of CTs toward one species affects the detection of non‐target species. We paired CTs from a permanent camera‐trapping grid (with 38 CTs) targeted at monitoring Eurasian lynx (Lynx lynx) in Innlandet County, Norway, with additional randomly placed CTs at two spatial scales (38 CTs within the same habitat patch and 38 CTs within the same 50‐km2 grid cell as the lynx‐targeted CTs) for three months. We combined multi‐scale occupancy models that enable the separation of large‐scale occupancy, CT‐scale site use, and detection probability with single‐scale occupancy models. This allowed us to study the effects of targeted placement and CT number on the detection probability of the target species (lynx) and seven non‐target mammal species (four carnivores, three herbivores, and one rodent). We found that all species, except moose (Alces alces), had the highest detection probability at lynx‐targeted CTs. Moose had equal detection probabilities at all three placement types. Adding extra CTs generally increased detection probabilities. Consequently, for all species, combining a lynx‐targeted CT with one or more randomly placed CTs, increased the accuracy and precision of occupancy estimates for 50‐km2 grid cells compared to single CT estimates. The placement of single CTs underestimated grid‐cell occupancy compared to known minimum occupancy and were similar to site‐use probability estimates of multi‐scale models. It is, however, uncertain to which spatial extent these site‐use probabilities refer. We therefore recommend the use of multiple (targeted) CTs to estimate occupancy in large grid cells and to interpret occupancy estimates from single CTs as site use of an, as of yet undefined, area surrounding the CT.

BAIT PREFERENCES BY DIFFERENT SMALL MAMMAL ASSEMBLAGES FOR EFFECTIVE CAGE-TRAPPING

The ecological study of small mammals often uses the cage-trapping method, installed with baits. Capture rates vary according to different baits used. We want to determine the bait preferences by different small mammal groups. The cage-trapping approach used common domestic bait types available, namely, aromatic banana, sweet potato with peanut butter, oil palm fruit, dried salted fish, jackfruit, and roasted coconut flesh. Sampling was conducted in three different habitat categories, namely urban, semi-urban, and recreational forests, located in Selangor, Malaysia, for one year. A total of 537 small mammals from 15 species were sampled, which was then grouped into seven groups (i.e., Rattus sp., Maxomys sp., Sundamys sp., Leopaldamys sabanus, Suncus murinus, squirrels, and Tupaia glis). Bait preferences were significantly different among the different small mammal groups, i.e., F (6,35) = 5.621, p = 0.000, with bananas shown to be most preferred bait, followed by oil palm fruits and sweet potatoes. Non-metric multidimensional scaling (nMDS) analysis revealed that the Rattus species encompassed the most diverse bait preference, while S. murinus and L. sabanus were the most selective. Muridae preferred sweet potatoes with peanut butter over bananas, while Sciuridae and Tupaiidae preferred bananas, and Soricidae preferred dried salted fish. This study elucidates the most effective bait selection for different small mammal assemblages, serving as a guide to increase capture rates when sampling targeted population of small mammals. Apart from that, it is helpful for effective rodent pest control.

Source pool diversity and proximity shape the compositional uniqueness of insular mammal assemblages worldwide

AbstractAimIslands have been the test bed of several theories in community ecology, biogeography, and evolutionary biology. Progress within these disciplines has given a more comprehensive and mechanistic understanding of the processes governing variation in species richness among islands. However, it remains unclear whether these same processes also explain variation in species and phylogenetic composition among islands. Integrating theory from ecology and biogeography, we infer the roles of dispersal, selection, and stochasticity on the composition of insular assemblages within archipelagos. We further assess the influence of source pool diversity and connectivity on the compositional uniqueness of insular assemblages.LocationIsland systems worldwide.TaxonMammals.MethodsWe compiled data on species composition of nonvolant mammals on ~200 islands in nine archipelagos distributed worldwide from the literature. We used variation partitioning to quantify the relative influence of the environment (selection) and geographic distance (dispersal) relative to a null model (stochasticity, randomness) on taxonomic and phylogenetic compositional turnover within archipelagos. We then used a linear mixed model to gain further insight into the underlying mechanisms shaping variation in assemblage composition among islands at a global scale. Specifically, we assessed the influence of source pool diversity, isolation from the source pool, and island characteristics on compositional uniqueness.ResultsOur results suggest that within‐archipelago variation in the composition of insular mammal assemblages is associated with stochastic or unmeasured processes rather than abiotic selection or dispersal limitation. The diversity and proximity of the source pool, as well as some island characteristics, explained variation in phylogenetic, but not taxonomic, compositional uniqueness globally. Globally, isolated islands associated with phylogenetically diverse source pools exhibit high phylogenetic uniqueness whereas well‐connected islands associated with phylogenetically clustered source pools show the opposite trend. Phylogenetically unique assemblages also tend occur on islands with a small elevational span and low annual temperature variation.Main conclusionsTaken together, our results suggest that source pool diversity, along with the potential for colonization from those pools, has a strong influence on the composition of insular mammal assemblages worldwide.

Replacing native mammal assemblages with livestock in African savannahs, impacts dung beetle diversity and reduces body size

Replacement of complex assemblages of native mammal fauna with livestock species reduces niche heterogeneity. This negatively affects taxa such as dung beetles, which depend on them and can, in turn, affect ecosystem functioning. We assessed the response of dung beetle diversity, biomass and body condition to cattle-farming pressures in protected areas (PAs) and adjacent farms in the savannah biome of northern Namibia. We hypothesized that rich native mammal assemblages are essential to maintain dung beetle diversity and overall biomass. We further explored whether the low-quality dung resources on farms would lead to a decrease in individual body size for species found on both farms and PAs. Overall dung beetle richness increased with higher mammal richness but not relative abundance, demonstrating that a rich native vertebrate assemblage promotes dung beetle richness. Overall dung beetle biomass was lower on farms, but abundance showed no difference. Large-bodied dung specialist species, which are known to be functionally superior, were absent on farms while smaller generalist species proliferated. Furthermore, a large proportion of individuals of species common to both farms and PAs were physically smaller on farms, indicating reduced body condition. Our results show that a high diversity of native mammals maintains dung beetle diversity and higher biomass on PAs. A decrease in native dung on farms leads to reduced body mass, likely negatively impacting ecological function. These results suggest that the conservation of dung beetles and their functions in the expansive African savannah ecosystems is dependent on a complex mix of native mammal species.

AN OVERVIEW ON THE LATE MIOCENE VERTEBRATES FROM THE FISSURE FILLINGS OF MONTICINO QUARRY (BRISIGHELLA, ITALY), WITH NEW DATA ON NON-MAMMALIAN TAXA

The latest Messinian Monticino Quarry fissure fillings, near Brisighella in Italy, are well known for their diverse mammal fauna. Conversely, little is known about other vertebrates from this rich site. Beside presenting an overview of the mammals, here we describe fish, amphibian, reptile, and bird remains, identifying three, eight, at least 18, and five taxa, respectively. Some of these represent the oldest occurrences either worldwide (an erycine snake related to Eryx jaculus, Malpolon, and otidids birds) or locally (common toads in the Apennine Peninsula and eremiadine lacertids in Europe, the latter being also the only known occurrence of these lizards in Italy). Altogether, the vertebrate fauna from Monticino Quarry is indicative of a complex palaeoenvironment, which was warm and somehow dry. Water bodies were indeed present though, as well as a patchy set of habitats with loose or sandy soils, rocky outcrops, open biotopes, and (even though maybe to a lesser extent) wooded areas. Furthermore, estuarine or lagoonal conditions were likely present near the depositional site. From a palaeobiogeographical point of view, the non-mammal vertebrate assemblage from Monticino Quarry shows considerable Afro-Asian affinities at least for some components. In the context of the Italian late Miocene continental vertebrate assemblages, that of Monticino is remarkably similar to those from the Piedmont Basin, especially if compared with the Tusco-Sardinian area, Apulian Platform, Calabrian Arc and Sicily. This is consistent with the palaeobiogeographic scenario defined by mammal assemblages, with northcentral Italy, Tuscany and Sardinia, Apulian Platform, and Calabria and Sicily representing separated bioprovinces.

A new addition to Pleistocene megalonychid sloth diversity in the northern Neotropics

We report here a new record of a megalonychid sloth from a late Pleistocene mammal assemblage from Cueva de Iglesitas (Mi.50), Caracas, Venezuela. This new site, the first with a Pleistocene fauna found in the vicinity of Caracas, is in a pristine geological and stratigraphic area and preserves previously untouched sediments containing fossils that provide important information about the late Pleistocene paleofauna and paleoenvironment of Caracas and the southwestern Caribbean region. A preliminary assessment of the relationship of this new sloth to other members of the Megalonychidae is presented.

The role of protected and unprotected forest remnants for mammal conservation in a megadiverse Neotropical hotspot

The Brazilian Atlantic Forest of Southern Bahia is a megadiverse region given its remarkable number of species and endemism. Despite being a priority region for biodiversity conservation, the role of protected and unprotected forest remnants for long-term species conservation is unknown. Here, we unveil the main patterns of occurrence and distribution of medium- and large-sized mammals in remnants of the Atlantic Forest of Southern Bahia, to generate subsidies for applied conservation strategies. We recorded mammals using camera-traps, active search, and/or line-transect surveys and complemented our species list with literature data. We thus obtained information on richness attributes, relative abundance, and biomass of mammal species per forest remnant, compared assemblages in protected and unprotected areas, and finally investigated both species-area and biomass-area relationships. From 72 forest remnants assessed, we recorded 45 mammal species, including 19 threatened locally. Protected areas were richer in species, especially concerning threatened ones, and concentrated most of the mammal biomass, which presented consistently low values for most areas. The positive and significant species-area and biomass-area relationships further corroborate these patterns since protected areas are larger in size. Despite the historic anthropogenic pressures, we conclude that Southern Bahia still harbors an expressive mammal diversity, with protected areas being critical to maintain most of the species' richness and biomass across the entire region. Nevertheless, small unprotected remnants (<100 ha) safeguard mammal species, including threatened ones, stressing their importance to maintain mammal assemblages in one of the most important hotpoints of the entire biome.

A new mammalian assemblage for Guanaco Formation (northwestern Argentina), and the description of a new genus of New World porcupine

The Guanaco Formation (Orán Group) is one of the Neogene units outcropping in the Subandean region of northwestern Argentina. The fossil assemblage from the middle section was studied in a few contributions. Here we present new remains for the middle section (~6.3 Ma) and the first records for the upper section (<5.7 Ma) of this unit, collected in the Río Chico locality of Jujuy Province. The remains from the middle section include very well-preserved cranium, cephalic armor, and part of the carapace of a small glyptodontid assigned to Cranithlastus xibiensis, representing the second specimen known for the species. The remains from upper section represent the youngest mammalian association known for the Guanaco Formation, and include fragmentary remains of five caviomorph rodent taxa, including Lagostomus sp., Caviinae indet., Caviodon sp., Octodontoidea indet., the latter three representing new taxa for the unit. The fifth taxon of the upper section corresponds to a new genus and species of porcupine (Erethizontidae), represented by a fragment of left maxilla with DP4-M1. This and other recent paleontological studies, together with sedimentological and geochronological data of Guanaco Formation, are contributing to the knowledge of the past diversity of the area, and the faunistic and environmental evolution of the Central Andes ecoregions in northwestern Argentina. The preliminary characterization of the youngest faunistic association reveals the presence of forest-dweller taxa with conservative occlusal and postcranial morphologies, concurs with the context of local and regional progressive break-up of basins, increasing of moisture supply, and development of powerful streams related to a stepper slopes landscape. The evidence supports forested foothill environments, including subtropical components, for the upper levels of the Guanaco Formation, giving clues regarding to the tempo and mode in which Chacoan-like communities were replaced by subtropical mountain rain forests communities of Yungas.