Anthropogenic modification of a giant ground sloth tooth from Brazil supported by a multi-disciplinary approach.

Identifying evidence of human modification of extinct animal remains, such as Pleistocene megafauna, is challenging due to the similarity of anthropogenic and non-anthropogenic taphonomic features observed under optical microscopy. Here, we re-investigate a Late Pleistocene ground sloth tooth from northeast Brazil, previously suggested as human-modified based only on optical observation. To characterize the macro- and micro-morphological characteristics of the marks preserved in this tooth and evaluate potential human modification, we used stereomicroscope and scanning electron microscopy (SEM) supplemented by energy dispersive spectroscopy (EDS), UV photoluminescence (UV/PL), synchrotron-based X-ray fluorescence (SR-XRF), and synchrotron micro-computed tomography (SR-µCT). These methods allowed us to discriminate non-anthropogenic taphonomic features (root and sedimentary damage), anthropogenic marks, and histological features. The latter shows the infiltration of exogenous elements into the dentine from the sediments. Our evidence demonstrates the sequence of anthropogenic and non-anthropogenic taphonomic modification of this tooth and supports its initial intentional modification by humans. We highlight the benefits of emerging imaging and spectral imaging techniques to investigate and diagnose human modification in fossil and archaeological records and propose that human modification of tooth tissues should be further considered when studying possibly anthropogenically altered fossil remains.

The reorganization of predator-prey networks over 20 million years explains extinction patterns of mammalian carnivores.

Linking the species interactions occurring at the scale of local communities to their potential impact at evolutionary timescales is challenging. Here, we used the high-resolution fossil record of mammals from the Iberian Peninsula to reconstruct a timeseries of trophic networks spanning more than 20 million years and asked whether predator-prey interactions affected regional extinction patterns. We found that, despite small changes in species richness, trophic networks showed long-term trends, gradually losing interactions and becoming sparser towards the present. This restructuring of the ecological networks was driven by the loss of medium-sized herbivores, which reduced prey availability for predators. The decrease in prey availability was associated with predator longevity, such that predators with less available prey had greater extinction risk. These results not only reveal long-term trends in network structure but suggest that prey species richness in ecological communities may shape large scale patterns of extinction and persistence among predators.

The latest freshwater giants: a new Peltocephalus (Pleurodira: Podocnemididae) turtle from the Late Pleistocene of the Brazilian Amazon.

Overkill of large mammals is recognized as a key driver of Pleistocene megafaunal extinctions in the Americas and Australia. While this phenomenon primarily affected mega-mammals, its impact on large Quaternary reptiles has been debated. Freshwater turtles, due to the scarcity of giant forms in the Quaternary record, have been largely neglected in such discussions. Here we present a new giant podocnemidid turtle, Peltocephalus maturin sp. nov., from the Late Pleistocene Rio Madeira Formation in the Brazilian Amazon, that challenges this assumption. Morphological and phylogenetic analyses of the holotype, a massive partial lower jaw, reveal close affinities to extant Amazonian species and suggest an omnivorous diet. Body size regressions indicate Pe. maturin possibly reached about 180 cm in carapace length and is among the largest freshwater turtles ever found. This finding presents the latest known occurrence of giant freshwater turtles, hinting at coexistence with early human inhabitants in the Amazon.

Microplastic occurrence and phthalate ester levels in neuston samples and skin biopsies of filter-feeding megafauna from La Paz Bay (Mexico).

The impacts of microplastics on filter feeders megafauna have recently received increased attention. These organisms are potentially exposed to plastic ingestion and the release of added/sorbed contaminants during feeding activities. An assessment of microplastic abundance and the chemical impact of Phthalates esters (PAEs) were performed in neustonic samples and skin biopsies of Balaenoptera physalus and Rhincodon typus inhabiting the Gulf of California (Mexico). Sixty-eight percent of the net tows contained plastics with a maximum of 0.24 items/m3 mainly composed of polyethylene fragments. PAE levels were detected both in environmental and skin biopsy samples, with the highest values in the fin whale specimens (5291 ng/g d.w). Plasticizer fingerprint showed a similar distribution pattern between neustonic samples and filter-feeding species, with DEHP and MBP having the highest concentrations. The detection of PAE levels confirmed their potential role as plastic tracers and give preliminary information about the toxicological status of these species feeding in La Paz Bay.

Kill site database: A unified dataset on human-megafauna interactions across time and space.

The database presented in this data article is related to the paper "Megafauna kill sites in South America: a critical review" [1]. It includes a list of 134 publications on human-megafauna interaction, with 69 archaeological sites showing human-megafauna interaction. From these sites, 44 present a minimum human-megafauna association, from which up to 17 megafauna kill sites were classified, with up to 15 exploited extinct megafauna taxa. It also provides a list of current taxonomic classifications of extinct megafauna that humans have exploited according to empirical evidence presented in the related paper. The megafauna kill sites were classified based on five restrictive criteria according to Grayson and Meltzer's (2015, 2002), Borrero's (2009) and Mothé et al.'s (2020) protocol. The kill sites database reflects the empirical evidence on megafauna exploitation by humans available in scientific literature and is useful to understand the human-megafauna interactions in the late Quaternary. Finally, we also provide our online repository (www.killsitedatabase.com), an initiative to unify the evidence on megafauna kill sites (and their related data) worldwide, starting in South America.

Solid waste ingestion by marine megafauna on Southeast Brazilian coast.

The disparities in the ecology and behavior of marine megafauna may influence their susceptibility to solid waste ingestion; however, this relationship has been underestimated along the Brazilian coast. We analyzed a dataset of 7261 marine megafauna (45 species) necropsied to investigate the influence of their foraging strategies on solid waste ingestion. A total of 1240 specimens ingested solid waste with over 55 % (689) that ingested plastic. Sea turtles were the most impacted taxa, while cetaceans present the lowest frequency. Some characteristics such as regurgitation (e.g., Suliformes and Charadriiformes seabirds) or possess complex foraging strategies (e.g., cetaceans echolocation) may mitigate the negative effects of solid waste ingestion. Also, the variability over the monitoring program likely was influenced by the volume of pollutants transported to the ocean during flood periods, and level of staff training. This study serves as a valuable baseline for solid waste management actions and marine megafauna conservation efforts.

Ice Age megafauna rock art in the Colombian Amazon?

Megafauna paintings have accompanied the earliest archaeological contexts across the continents, revealing a fundamental inter-relationship between early humans and megafauna during the global human expansion as unfamiliar landscapes were humanized and identities built into new territories. However, the identification of extinct megafauna from rock art is controversial. Here, we examine potential megafauna depictions in the rock art of Serranía de la Lindosa, Colombian Amazon, that includes a giant sloth, a gomphothere, a camelid, horses and three-toed ungulates with trunks. We argue that they are Ice Age rock art based on the (i) naturalistic appearance and diagnostic morphological features of the animal images, (ii) late Pleistocene archaeological dates from La Lindosa confirming the contemporaneity of humans and megafauna, (iii) recovery of ochre pigments in late Pleistocene archaeological strata, (iv) the presence of most megafauna identified in the region during the late Pleistocene as attested by archaeological and palaeontological records, and (v) widespread depiction of extinct megafauna in rock art across the Americas. Our findings contribute to the emerging picture of considerable geographical and stylistic variation of geometric and figurative rock art from early human occupations across South America. Lastly, we discuss the implications of our findings for understanding the early human history of tropical South America. This article is part of the theme issue 'Tropical forests in the deep human past'.

Using drones and ROV to assess the vulnerability of marine megafauna to the Fundão tailings dam collapse.

The ecology and life history of marine megafauna can answer the ecological importance of a region. This study assesses and monitors the abundance and home range of sea turtles, seabirds, marine mammals and the association with coastal microhabitats in potentially impacted areas at the Rio Doce river mouth, Comboios, and Piraquê-açu river mouth after the collapse of the Fundão dam. Remotely Operated Vehicles (ROV) and UAVs (Unmanned Aerial Vehicles, or drones) were used for megafauna species identification, behavior, population data, habitat characterization, and monitoring of environmental protection areas. The species Sotalia guianensis and Pontoporia blainvillei were the most recorded cetaceans, and the main observed behavior was feeding. Guiana dolphin (S. guianensis) occurs in greater density in the Rio Doce river mouth region, resulting in more than 10 sightings/km2, while franciscana (P. blainvillei) were the most concentrated Comboios area. The seabirds (all species) had up to 15 sightings/km2 at the Rio Doce river mouth, the highest density among sampled areas. The green turtle (Chelonia mydas) was the most frequently recorded, followed by the leatherback turtle (Dermochelys coriacea). The green turtle occurred at a higher concentration at the Piraquê-Açu river mouth (above 6 sightings/km2). The sites closest to Rio Doce river mouth and Comboios predominantly showed mud bottoms, while those at Piraquê-Açu mouth were mostly reef structures. The estuarine areas showed greater importance for megafauna than marine areas.

Deep classification of cut-marks on bones from Arroyo del Vizcaíno (Uruguay).

The earliest widely accepted presence of humans in America dates to approximately 17.5 cal kyr BP, at the end of the Last Glacial Maximum (LGM). Among other evidence, this presence is attested by stone tools and associated cut-marks and other bone surface modifications (BSM), interpreted as the result of the consumption of animals by humans. Claims of an older human presence in the continent have been made based on the proposed anthropogenic modification of faunal remains; however, these have been controversial due to the highly subjective nature of the interpretations. Here, we employ advanced deep learning algorithms to objectively increase the accuracy of BSM identification on bones. With several models that exhibit BSM classification accuracies greater than 94%, we use ensemble learning techniques to robustly classify a selected sample of BSM from the approximately 30 kyr BP site of Arroyo del Vizcaíno, Uruguay. Our results confidently show the presence of cut-marks imparted by stone tools on bones at the site. This result supports an earlier presence of humans in the American continent, expanding additional genetic and archaeological evidence of a human LGM and pre-LGM presence in the continent.

Detection of the elusive Dwarf sperm whale (Kogia sima) using environmental DNA at Malpelo island (Eastern Pacific, Colombia).

Monitoring large marine mammals is challenging due to their low abundances in general, an ability to move over large distances and wide geographical range sizes.The distribution of the pygmy (Kogia breviceps) and dwarf (Kogia sima) sperm whales is informed by relatively rare sightings, which does not permit accurate estimates of their distribution ranges. Hence, their conservation status has long remained Data Deficient (DD) in the Red list of the International Union for Conservation of Nature (IUCN), which prevent appropriate conservation measures.Environmental DNA (eDNA) metabarcoding uses DNA traces left by organisms in their environments to detect the presence of targeted taxon, and is here proved to be useful to increase our knowledge on the distribution of rare but emblematic megafauna.Retrieving eDNA from filtered surface water provides the first detection of the Dwarf sperm whale (Kogia sima) around the remote Malpelo island (Colombia).Environmental DNA collected during oceanic missions can generate better knowledge on rare but emblematic animals even in regions that are generally well sampled for other taxa.

The dermal armor of mylodontid sloths (Mammalia, Xenarthra) from Cueva del Milodón (Última Esperanza, Chile).

Dermal ossifications (osteoderms, dermal ossicles, osteoscutes) appear independently in various tetrapod lineages. In mammals, however, dermal ossifications are only present in some members of Xenarthra. This clade includes Cingulata (armadillos and their relatives), and Pilosa, including Vermilingua (anteaters) and Folivora (sloths). In extant xenarthrans, osteoderms are invariably present in cingulates whereas they are absent in pilosans. Among extinct sloths, however, a limited number of taxa possessed dermal ossifications. Records of mummified skins of ground sloths bearing osteoderms found in Cueva del Milodón (Southern Chile), with a late Pleistocene age, allowed us to analyze their micro- and macroscopic morphology. The main goal of this study is to closely examine a portion of a mylodontid skin portion using radiography. The arrangement, morphology and internal structure of the ossicles are analyzed and the results are discussed in the context of previous research. The results we obtained indicate that ossicles vary in shape and size, and the integument has four different patterns of arrangement of the ossicles: that is, areas without ossicles, disorganized ossicles, rows, and mosaic areas. The latter has two variants, with clusters of ossicles forming rosettes or stars. Thin sections of the ossicles allowed us to recognize and describe anatomical features of the bone and its mode of growth. Finally, paleobiological and functional considerations of the dermal armor are discussed along with its phylogenetic and chronological implications.

Mollusk bycatch in trawl fisheries targeting the Atlantic seabob shrimp Xiphopenaeus kroyeri on the coast of Sergipe, northeastern Brazil

The malacofauna bycatch of sea-bob shrimp Xiphopenaeus kroyeri (Heller, 1862) trawl fisheries on the coast of Sergipe was studied for 5 years. The malacofauna bycatch considered was obtained in nine oceanographic sampling campaigns carried out between May 1999 and June 2003 in 18 stations distributed in six transects along depths of 10, 20 and 30 m. A total of 2,669 individuals of mollusk belonging to 54 species were captured on the 18 sea-bob shrimp trawl stations carried out along the coast of Sergipe. The considerable richness of mollusks was composed by 19 families and 31 species of gastropods, 12 families and 19 species of bivalves and 2 families and 4 species of cephalopods. The highest abundance were observed at stations 13 (373 individuals) and 16 (685 individuals) that represents the lowest depth (10 m) and the richness was higher at stations 15 and 12 (17 and 11 species, respectively) both located at the highest depth (30 m). Cephalopods had high frequency of occurrence being collected in all the stations and by far the most abundant group with a total of 2,488 individuals captured. On the other hand, gastropods (with 142 individuals found in 83.3% of stations) and bivalves (about 1% of the individuals collected) contribute with a much smaller percentage of individuals captured. Lolliguncula brevis (Blainville, 1823) was most representative cephalopod in number and frequency of occurrence. Arcidae, Conidae, Muricidae and Strombidae were the families with the higher number of species in the trawl-fishery. Among bivalves, Pitar arestus (Dall & Simpson, 1901) and Spathochlamys benedicti (Verrill & Bush [in Verrill], 1897) were the species with higher frequency of occurrence. Although the considerable sample effort and a number of mollusks captured as bycath, the richness estimators indicated that the species richness could increase with additional sampling effort in the study area...(AU)

Mollusk bycatch in trawl fisheries targeting the Atlantic seabob shrimp Xiphopenaeus kroyeri on the coast of Sergipe, northeastern Brazil

The malacofauna bycatch of sea-bob shrimp Xiphopenaeus kroyeri (Heller, 1862) trawl fisheries on the coast of Sergipe was studied for 5 years. The malacofauna bycatch considered was obtained in nine oceanographic sampling campaigns carried out between May 1999 and June 2003 in 18 stations distributed in six transects along depths of 10, 20 and 30 m. A total of 2,669 individuals of mollusk belonging to 54 species were captured on the 18 sea-bob shrimp trawl stations carried out along the coast of Sergipe. The considerable richness of mollusks was composed by 19 families and 31 species of gastropods, 12 families and 19 species of bivalves and 2 families and 4 species of cephalopods. The highest abundance were observed at stations 13 (373 individuals) and 16 (685 individuals) that represents the lowest depth (10 m) and the richness was higher at stations 15 and 12 (17 and 11 species, respectively) both located at the highest depth (30 m). Cephalopods had high frequency of occurrence being collected in all the stations and by far the most abundant group with a total of 2,488 individuals captured. On the other hand, gastropods (with 142 individuals found in 83.3% of stations) and bivalves (about 1% of the individuals collected) contribute with a much smaller percentage of individuals captured. Lolliguncula brevis (Blainville, 1823) was most representative cephalopod in number and frequency of occurrence. Arcidae, Conidae, Muricidae and Strombidae were the families with the higher number of species in the trawl-fishery. Among bivalves, Pitar arestus (Dall & Simpson, 1901) and Spathochlamys benedicti (Verrill & Bush [in Verrill], 1897) were the species with higher frequency of occurrence. Although the considerable sample effort and a number of mollusks captured as bycath, the richness estimators indicated that the species richness could increase with additional sampling effort in the study area...

The Onthophagus fuscus (Coleoptera: Scarabaeidae) species complex: an update and the description of a new species.

The Onthophagus fuscus Boucomont, 1932 (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini) species complex has a total of eight species, one of which is a new species (Onthophagus orizabensis new species) and three are elevated from the subspecies level (O. canescens Zunino Halffter, 1988 new rank; O. mycetorum Zunino Halffter, 1988 new rank; O. parafuscus Zunino Halffter, 2005 new rank). Onthophagus navarretorum Delgado Capistan, 1996 is included, while Onthophagus semiopacus has been removed from the species complex. The distribution map and key for the identification of species in this species complex are updated. Habitat preferences, ecological tolerance, and the restriction of this species complex to the mountains of the Mexican Transition Zone are discussed.

Methodological innovations for the study of irreplaceable samples reveal giardiasis in extinct animals (Nothrotherium maquinense and Palaeolama maior).

The use of diagnostic methods that prevent irreplaceable samples (from museum collections, archaeological and paleontological samples) of being consumed or that increase their yield is relevant. For museum collections, archaeological and paleontological samples it is essential to conserve samples, subsamples or portions for future research. We are addressing methods for conservation of irreplaceable samples that could be fully consumed. Innovations in methodologies that are used in studies of Paleoparasitology and Paleomicrobiology will contribute to the preservation of collections. Therefore, to the development of archaeology and paleontology in the future, we evaluated whether the discarded material of the immunochromatography test could be used for molecular diagnosis and vice versa. We used a genotyped experimental coprolite positive for Giardia duodenalis. The diagnosis was positive for giardiasis in both cases. This methodology can be corroborated with the coprolite of a Paleolama maior (extinct llama) previously diagnosed for G. duodenalis with an immunoenzymatic test. The residue of the pre-digestion step of the DNA extraction before adding Proteinase K was confirmed positive with the immunochromatographic test. Also, the DNA extraction residue from a coprolite of Nothrotherium maquinense (ground sloth) was tested positive with immunochromatographic test for G. duodenalis. These are the oldest findings for G. duodenalis confirming that this intestinal parasite occurred among Northeastern Brazilian Megafauna animals from the late Pleistocene period, correlated to human occupation. The relevance of these results will allow the study by different methodological approaches from a small amount of material, reusing discarded materials.

Variaciones adaptativas en la talla de la megafauna bentónica de fondos blandos tropicales en función de parámetros bióticos y abióticos / Adaptive variation in size of tropical soft bottom benthic megafauna related to biotic and abiotic factors

Resumen: Entender y predecir variaciones en el tamaño de los invertebrados megabentónicos sigue siendo un desafío importante en macroecología marina. Este estudio se realizó para identificar tendencias de cambio en la talla de la megafauna bentónica de fondos sedimentarios tropicales y conocer la influencia de variables que pueden determinar el tamaño de estos organismos, evaluando hipótesis y paradigmas ecológicos de mar profundo originados en zonas subtropicales y templadas. El área de estudio abarcó toda la plataforma continental del Caribe colombiano. Los ejemplares se recolectaron en 1998, 2001 y 2005 con red demersal semi-globo, entre 10 y 500 m de profundidad. Se seleccionaron las especies mejor representadas: Eudolium crosseanum, Cosmioconcha nitens, Nuculana acuta (moluscos), Astropecten alligator, Brissopsis atlantica, B. elongata (equinodermos), Anasimus latus, Chasmocarcinus cylindricus y Achelous spinicarpus (crustáceos). Para detectar tendencias significativas de cambio de tamaño, e inferir la influencia de variables bióticas y ambientales, se emplearon modelos aditivos generalizados, donde la talla fue la variable respuesta y las variables predictivas fueron: profundidad, temperatura, densidad intraespecífica e interespecífica, riqueza, latitud y longitud. Se midieron 7 000 ejemplares en total. Seis especies presentaron un incremento de la talla con el aumento de la profundidad y la disminución de la temperatura. Dichas especies abarcaron ámbitos batimétricos que superaron los 10 °C de diferencia entre zonas someras y profundas. Geográficamente se presentó una marcada disminución de tallas en el área de influencia de la desembocadura del río Magdalena, debida posiblemente a los fuertes cambios físicosquímicos que este río genera, principalmente porque es la zona con menos productividad primaria planctónica de toda el área de estudio. Hacia el norte de la desembocadura del río Magdalena se presentó un notorio aumento de tamaños entre los (74° - 71°W y 11° - 13°N), que puede deberse a la surgencia que se presenta en el norte del Caribe colombiano. La relación entre la densidad de individuos y la talla no fue clara. Sin embargo cinco especies mostraron una relación inversa con la densidad intraespecífica, y tres con la interespecífica. Temperatura y profundidad fueron las variables que mejor explicaron los cambios de talla detectados. La mayoría de especies presentaron un aumento de dimensiones corporales con la disminución de la temperatura en el perfil batimétrico. La tendencia al aumento de tallas con la profundidad es contraria a lo indicado por los modelos teóricos de talla óptima (pero acorde con algunos estudios más recientes), que predicen un decrecimiento del tamaño de los organismos con el incremento de la profundidad, debido a la disminución de nutrientes hacia zonas profundas del océano. Es posible que el aumento de tamaño sea una estrategia adaptativa para la maximización de la energía, como ocurre con muchos organismos en las porciones más frías de su ámbito de distribución. Futuros estudios en el Caribe deberían examinar variaciones en la talla de la megafauna bentónica en zonas más profundas (más de 500 m), donde la temperatura varía menos, razón por la cual otros factores pueden ser más importantes para determinar el tamaño de estos organismos.

Abstract: Understanding and predicting adaptations in body size of megabenthic invertebrates remains a major challenge in marine macroecology. This study was conducted in order to investigate size variations of benthic megafauna in the tropics and to identify the effect of biotic and abiotic factors that may produce changes to these organisms, testing unresolved hypothesis and paradigms of deep sea ecology from subtropical and temperate areas. The study area covered the continental shelf of the Colombian Caribbean. The samples were collected during 1998, 2001 and 2005, using semi-globe demersal net for a water depth of 10 to 500 m. The most common species were selected for further study: Eudolium crosseanum, Cosmioconcha nitens, Nuculana acuta (mollusks), Astropecten alligator, Brissopsis atlantica, B. elongata (equinoderms), Anasimus latus, Chasmocarcinus cylindricus and Achelous spinicarpus (crustaceans). Generalized Additive Models were used to detect significant changes in size and to infer the effects of biotic and environmental factors on organisms' size. The dependent variable was size and the predicting model variables were depth, temperature, intraspecific density, interspecific density, richness, latitude, and longitude. A total of 7 000 individuals were measured. Six species showed an increase in body size towards deeper and colder sites. These species inhabit shallow and deep environments that exceed a variation in temperature of 10 °C. There was a remarkable size reduction in areas affected by the Magdalena River, possibly due to major physicochemical changes caused by the river. This region has the lowest planktonic primary productivity within the study area. An increase in sizes was observed north of the Magdalena River (74° - 71°W & 11° - 13°N), which may be attributable to the coastal upwelling occurring in this part of Colombia. The relationship between the density of benthic organisms and size was not clear. However, five species showed an inverse relation with intraspecific density and three with interspecific density. Temperature and depth were the variables that best explained the variations in size. Most of the studied species showed an increase in body size when temperature dropped along the bathymetric range. The trend of increasing size in deeper zones is contrary to the prediction of the optimal size theoretical model (but consistent with recent studies), which indicates a reduction in organisms' size in the deep sea, due to food limitation with increasing depth. It is possible that this increase in size is an adaptation to maximize energy, which is frequently observed in the coldest habitats of several species. Future studies in Caribbean should examine variations in size of benthic megafauna towards deeper zones (more than 500 m), were temperature is less variable and then other factors can play a more important role determining the size of these organisms. Rev. Biol. Trop. 65 (3): 1002-1021. Epub 2017 September 01.

Phylogeny and biogeography of Maclura (Moraceae) and the origin of an anachronistic fruit.

BACKGROUND AND AIMS: Maclura (ca. 12spp., Moraceae) is a widespread genus of trees and woody climbers found on five continents. Maclura pomifera, the Osage orange, is considered a classic example of an anachronistic fruit. Native to the central USA, the grapefruit-sized Osage oranges are unpalatable and have no known extant native dispersers, leading to speculation that the fruits were adapted to extinct megafauna. Our aim was to reconstruct the phylogeny, estimate divergence dates, and infer ancestral ranges of Maclura in order to test the monophyly of subgeneric classifications and to understand evolution and dispersal patterns in this globally distributed group. METHODS: Employing Bayesian and maximum-likelihood methods, we reconstructed the Maclura phylogeny using two nuclear and five chloroplast loci from all Maclura species and outgroups representing all Moraceae tribes. We reconstructed ancestral ranges and syncarp sizes using a family level dated tree, and used Ornstein-Uhlenbeck models to test for significant changes in syncarp size in the Osage orange lineage. KEY RESULTS: Our analyses support a monophyletic Maclura with a Paleocene crown. Subgeneric sections were monophyletic except for the geographically-disjunct Cardiogyne. There was strong support for current species delineations except in the widespread M. cochinchinensis. South America was reconstructed as the ancestral range for Maclura with subsequent colonization of Africa and the northern hemisphere. The clade containing M. pomifera likely diverged in the Oligocene, closely coinciding with crown divergence dates of the mammoth/mastodon and sloth clades that contain possible extinct dispersers. The best fitting model for syncarp size evolution indicated an increase in both syncarp size and the rate of syncarp size evolution in the Osage orange lineage. CONCLUSIONS: We conclude that our findings are consistent with the hypothesis that M. pomifera was adapted to dispersal by extinct megafauna. In addition, we consider dispersal rather than vicariance to be most likely responsible for the present distribution of Maclura, as crown divergence post-dated the separation of Africa and South America. We propose revised sectional delimitations based on the phylogeny. This study represents a complete phylogenetic and biogeographic analysis of this globally distributed genus and provides a basis for future work, including a taxonomic revision.

A new species of extinct Late Quaternary giant tortoise from Hispaniola.

Insular giant tortoise diversity has been depleted by Late Quaternary extinctions, but the taxonomic status of many extinct populations remains poorly understood due to limited available fossil or subfossil material, hindering our ability to reconstruct Quaternary island biotas and environments. Giant tortoises are absent from current-day insular Caribbean ecosystems, but tortoise remains from Quaternary deposits indicate the former widespread occurrence of these animals across the northern Caribbean. We report new Quaternary giant tortoise material from several cave sites in Pedernales Province, southern Dominican Republic, Hispaniola, representing at least seven individuals, which we describe as Chelonoidis marcanoi sp. nov. Although giant tortoise material was first reported from the Quaternary record of Hispaniola almost 35 years ago, tortoises are absent from most Quaternary deposits on the island, which has been studied extensively over the past century. The surprising abundance of giant tortoise remains in both vertical and horizontal caves in Hispaniola's semi-arid ecoregion may indicate that this species was adapted to open dry habitats and became restricted to a habitat refugium in southeastern Hispaniola following climatic-driven environmental change at the Pleistocene-Holocene boundary. Hispaniola's dry forest ecosystem may therefore have been shaped by giant tortoises for much of its evolutionary history.

The functional extinction of Andean megafauna.

Controversy exists over the cause and timing of the extinction of the Pleistocene megafauna. In the tropical Andes, deglaciation and associated rapid climate change began ~8,000 years before human arrival, providing an opportunity to separate the effects of climate change from human hunting on megafaunal extinction. We present a paleoecological record spanning the last 25,000 years from Lake Pacucha, Peru (3,100 m elevation). Fossil pollen, charcoal, diatoms, and the dung fungus Sporormiella, chronicle a two-stage megaherbivore population collapse. Sporormiella abundance, the proxy for megafaunal presence, fell sharply at ~21,000 years ago, but rebounded prior to a permanent decline between ~16,800 and 15,800 years ago. This two-stage decline in megaherbivores resulted in a functional extinction by ~15,800 years ago, 3,000 years earlier than known human occupation of the high Andes. Declining megaherbivore populations coincided with warm, wet intervals. Climatic instability and megafaunal population collapse triggered an ecological cascade that resulted in novel floral assemblages, and increases in woody species, fire frequency, and plant species that were sensitive to trampling. Our data revealed that Andean megafaunal populations collapsed due to positive feedbacks between habitat quality and climate change rather than human activity.