The steroid metabolome of pregnancy, insights into the maintenance of pregnancy and evolution of reproductive traits.

Modes of mammalian reproduction are diverse and not always conserved among related species. Progesterone is universally required to supports pregnancy but sites of synthesis and metabolic pathways vary widely. The steroid metabolome of mid-to late gestation was characterized, focusing on 5α-reduced pregnanes in species representing the Perissodactyla, Cetartiodactyla and Carnivora using mass spectrometry. Metabolomes and steroidogenic enzyme ortholog sequences were used in heirarchial analyses. Steroid metabolite profiles were similar within orders, whales within cetartiodactyls for instance, but with notable exceptions such as rhinoceros clustering with goats, and tapirs with pigs. Steroidogenic enzyme sequence clustering reflected expected evolutionary relationships but once again with exceptions. Human sequences (expected outgroups) clustered with perissodactyl CYP11A1, CYP17A1 and SRD5A1 gene orthologues, forming outgroups only for HSD17B1 and SRD5A2. Spotted hyena CYP19A1 clustered within the Perissodactyla, between rhinoceros and equid orthologues, whereas CYP17A1 clustered within the Carnivora. This variability highlights the random adoption of divergent physiological strategies as pregnancy evolved among genetically similar species.

Rewinding Extinction in the Northern White Rhinoceros: Genetically Diverse Induced Pluripotent Stem Cell Bank for Genetic Rescue.

Extinction rates are rising, and current conservation technologies may not be adequate for reducing species losses. Future conservation efforts may be aided by the generation of induced pluripotent stem cells (iPSCs) from highly endangered species. Generation of a set of iPSCs from multiple members of a species can capture some of the dwindling genetic diversity of a disappearing species. We generated iPSCs from fibroblasts cryopreserved in the Frozen Zoo®: nine genetically diverse individuals of the functionally extinct northern white rhinoceros (Ceratotherium simum cottoni) and two from the closely related southern white rhinoceros (Ceratotherium simum simum). We used a nonintegrating Sendai virus reprogramming method and developed analyses to confirm the cells' pluripotency and differentiation potential. This work is the first step of a long-term interdisciplinary plan to apply assisted reproduction techniques to the conservation of this highly endangered species. Advances in iPSC differentiation may enable generation of gametes in vitro from deceased and nonreproductive individuals that could be used to repopulate the species.

Ancient genomes reveal tropical bovid species in the Tibetan Plateau contributed to the prevalence of hunting game until the late Neolithic.

Local wild bovids have been determined to be important prey on the northeastern Tibetan Plateau (NETP), where hunting game was a major subsistence strategy until the late Neolithic, when farming lifestyles dominated in the neighboring Loess Plateau. However, the species affiliation and population ecology of these prehistoric wild bovids in the prehistoric NETP remain unknown. Ancient DNA (aDNA) analysis is highly informative in decoding this puzzle. Here, we applied aDNA analysis to fragmented bovid and rhinoceros specimens dating ∼5,200 y B.P. from the Neolithic site of Shannashuzha located in the marginal area of the NETP. Utilizing both whole genomes and mitochondrial DNA, our results demonstrate that the range of the present-day tropical gaur (Bos gaurus) extended as far north as the margins of the NETP during the late Neolithic from ∼29°N to ∼34°N. Furthermore, comparative analysis with zooarchaeological and paleoclimatic evidence indicated that a high summer temperature in the late Neolithic might have facilitated the northward expansion of tropical animals (at least gaur and Sumatran-like rhinoceros) to the NETP. This enriched the diversity of wildlife, thus providing abundant hunting resources for humans and facilitating the exploration of the Tibetan Plateau as one of the last habitats for hunting game in East Asia.

The origin of Rhinocerotoidea and phylogeny of Ceratomorpha (Mammalia, Perissodactyla).

Rhinoceroses have been considered to have originated from tapiroids in the middle Eocene; however, the transition remains controversial, and the first unequivocal rhinocerotoids appeared about 4 Ma later than the earliest tapiroids of the Early Eocene. Here we describe 5 genera and 6 new species of rhinoceroses recently discovered from the early Eocene to the early middle Eocene deposits of the Erlian Basin of Inner Mongolia, China. These new materials represent the earliest members of rhinocerotoids, forstercooperiids, and/or hyrachyids, and bridge the evolutionary gap between the early Eocene ceratomorphs and middle Eocene rhinocerotoids. The phylogenetic analyses using parsimony and Bayesian inference methods support their affinities with rhinocerotoids, and also illuminate the phylogenetic relationships and biogeography of Ceratomorpha, although some discrepancies are present between the two criteria. The nearly contemporary occurrence of various rhinocerotoids indicates that the divergence of different rhinocerotoid groups occurred no later than the late early Eocene, which is soon after the split between the rhinocerotoids and the tapiroids in the early early Eocene. However, the Bayesian tip-dating estimate suggests that the divergence of different ceratomorph groups occurred in the middle Paleocene.

Phylogenetic tree of Litopterna and Perissodactyla indicates a complex early history of hoofed mammals.

The Litopterna is an extinct clade of endemic South American ungulates that range from Paleocene up to late Pleistocene times. Because of their unique anatomy, litopterns are of uncertain phylogenetic affinities. However, some nineteenth century authors, considered litopterns as related to perissodactyl ungulates, a hypothesis recently sustained by molecular data. The aim of the present contribution is to include litopterns and other South American related taxa in a comprehensive phylogenetic analysis together with several extant and extinct basal perissodactyl ungulates. The analysis resulted in the nesting of litopterns and kin as successive stem-clades of crown Perissodactyla. Further, litopterns are not phylogenetically grouped with any North American basal ungulate, in agreement with some previous proposals. Presence of pan-perissodactyls in South America and India indicates that southern continents probably played an important role in the early evolution of hoofed mammals.

Divergent mammalian body size in a stable Eocene greenhouse climate.

A negative correlation between body size and the latitudinal temperature gradient is well established for extant terrestrial endotherms but less so in the fossil record. Here we analyze the middle Eocene site of Geiseltal (Germany), whose record is considered to span ca. 5 Myrs of gradual global cooling, and generate one of the most extensive mammalian Paleogene body size datasets outside North America. The δ18O and δ13C isotopic analysis of bioapatite reveals signatures indicative of a humid, subtropical forest with no apparent climatic change across Geiseltal. Yet, body mass of hippomorphs and tapiromorphs diverges rapidly from a respective median body size of 39 kg and 124 kg at the base of the succession to 26 kg and 223 kg at the top. We attribute the divergent body mass evolution to a disparity in lifestyle, in which both taxa maximize their body size-related selective advantages. Our results therefore support the view that intrinsic biotic processes are an important driver of body mass outside of abrupt climate events. Moreover, the taxonomy previously used to infer the duration of the Geiseltal biota is not reproducible, which precludes chronological correlation with Eocene marine temperature curves.

Perissodactyla (Rhinocerotidae and Equidae) from Kanapoi.

The Kanapoi collection of Rhinocerotidae, first studied by Hooijer and Patterson (1972), now consists of 25 specimens and substantial reinterpretation of their affinities is made here. Kanapoi post-dates the extinction of Brachypotherium and the whole collection belongs to the Dicerotini. It is important because it includes the type-specimen of Diceros praecox, a species that remains poorly known, but looks slightly larger and more primitive than the modern 'black' rhino, Diceros bicornis. A second species is probably ancestral to the modern 'white' rhino, Ceratotherium simum; it looks identical to the Pleistocene North African Ceratotherium mauritanicum, of which Ceratotherium efficax is probably a synonym. The evolution of the Dicerotini in Africa can be regarded as an increasing divergence in diet and related morphofunctional adaptations in the two lineages. The co-occurrence at Kanapoi of both Diceros and Ceratotherium, with distinct dietary preferences, suggests some habitat heterogeneity, although the low sample size prevents robust paleoecological conclusions. The Equidae are also rare and consist mostly of isolated teeth. I take the most parsimonious option of tentatively including all of them in a single species, whose identification is left open. Dental features of eastern African Pliocene to Pleistocene hipparions may reflect increasing adaptation to grazing.

A new early Eocene deperetellid tapiroid illuminates the origin of Deperetellidae and the pattern of premolar molarization in Perissodactyla.

Deperetellidae is a clade of peculiar, Asian endemic tapiroids from the early and middle Eocene. The previously published material mainly comprises maxillae, mandibles, and some postcranial elements. However, the absence of cranial materials and primitive representatives of the deperetellids obscures their phylogenetic relationships within Tapiroidea. Furthermore, derived deperetellids have completely molarized premolars, but the pattern of their evolution remains unclear. Here, we report a nearly complete skull and some carpals of a new basal deperetellid tapiroid, Irenolophus qii gen. et sp. nov., from the late early Eocene of the Erlian Basin, Inner Mongolia, China. We suggest that deperetellids (along with Tapiridae) probably also arose from some basal 'helaletids', based on the reduced, flat, lingually depressed metacones on the upper molars, the trend towards the bilophodonty on the lower molars, and a shallow narial notch with the premaxilla in contact with the nasal. The molarization of the premolars in Deperetellidae from Irenolophus through Teleolophus to Deperetella was initiated and gradually enhanced by the separation between the paraconule and the protocone. That pattern differs from the protocone-hypocone separation in helaletids, tapirids, and most rhinoceroses, and the metaconule-derived pseudohypocone in amynodontids. However, the specific relationship of deperetellids within Tapiroidea and the roles of different patterns of premolar molarization in perissodactyl evolution need further and comprehensive study.

Early Pleistocene enamel proteome from Dmanisi resolves Stephanorhinus phylogeny.

The sequencing of ancient DNA has enabled the reconstruction of speciation, migration and admixture events for extinct taxa1. However, the irreversible post-mortem degradation2 of ancient DNA has so far limited its recovery-outside permafrost areas-to specimens that are not older than approximately 0.5 million years (Myr)3. By contrast, tandem mass spectrometry has enabled the sequencing of approximately 1.5-Myr-old collagen type I4, and suggested the presence of protein residues in fossils of the Cretaceous period5-although with limited phylogenetic use6. In the absence of molecular evidence, the speciation of several extinct species of the Early and Middle Pleistocene epoch remains contentious. Here we address the phylogenetic relationships of the Eurasian Rhinocerotidae of the Pleistocene epoch7-9, using the proteome of dental enamel from a Stephanorhinus tooth that is approximately 1.77-Myr old, recovered from the archaeological site of Dmanisi (South Caucasus, Georgia)10. Molecular phylogenetic analyses place this Stephanorhinus as a sister group to the clade formed by the woolly rhinoceros (Coelodonta antiquitatis) and Merck's rhinoceros (Stephanorhinus kirchbergensis). We show that Coelodonta evolved from an early Stephanorhinus lineage, and that this latter genus includes at least two distinct evolutionary lines. The genus Stephanorhinus is therefore currently paraphyletic, and its systematic revision is needed. We demonstrate that sequencing the proteome of Early Pleistocene dental enamel overcomes the limitations of phylogenetic inference based on ancient collagen or DNA. Our approach also provides additional information about the sex and taxonomic assignment of other specimens from Dmanisi. Our findings reveal that proteomic investigation of ancient dental enamel-which is the hardest tissue in vertebrates11, and is highly abundant in the fossil record-can push the reconstruction of molecular evolution further back into the Early Pleistocene epoch, beyond the currently known limits of ancient DNA preservation.

Migratory behaviour predicts greater parasite diversity in ungulates.

Long-distance animal movements can increase exposure to diverse parasites, but can also reduce infection risk through escape from contaminated habitats or culling of infected individuals. These mechanisms have been demonstrated within and between populations in single-host/single-parasite interactions, but how long-distance movement behaviours shape parasite diversity and prevalence across host taxa is largely unknown. Using a comparative approach, we analyse the parasite communities of 93 migratory, nomadic and resident ungulate species. We find that migrants have higher parasite species richness than residents or nomads, even after considering other factors known to influence parasite diversity, such as body size and host geographical range area. Further analyses support a novel 'environmental tracking' hypothesis, whereby migration allows parasites to experience environments favourable to transmission year-round. In addition, the social aggregation and large group sizes that facilitate migration might increase infection risk for migrants. By contrast, we find little support for previously proposed hypotheses, including migratory escape and culling, in explaining the relationship between host movement and parasitism in mammals at this cross-species scale. Our findings, which support mechanistic links between long-distance movement and increased parasite richness at the species level, could help predict the effects of future environmental change on parasitism in migratory animals.

The novel primers for mammal species identification-based mitochondrial cytochrome b sequence: implication for reserved wild animals in Thailand and endangered mammal species in Southeast Asia.

We presented the powerful techniques for species identification using the short amplicon of mitochondrial cytochrome b gene sequence. Two faecal samples and one single hair sample of the Asian tapir were tested using the new cytochrome b primers. The results showed a high sequence similarity with the mainland Asian tapir group. The comparative sequence analysis of the reserved wild mammals in Thailand and the other endangered mammal species from Southeast Asia comprehensibly verified the potential of our novel primers. The forward and reverse primers were 94.2 and 93.2%, respectively, by the average value of the sequence identity among 77 species sequences, and the overall mean distance was 35.9%. This development technique could provide rapid, simple, and reliable tools for species confirmation. Especially, it could recognize the problematic biological specimens contained less DNA material from illegal products and assist with wildlife crime investigation of threatened species and related forensic casework.

Genetic diversity of the captive Asian tapir population in Thailand, based on mitochondrial control region sequence data and the comparison of its nucleotide structure with Brazilian tapir.

The Asian tapir (Tapirus indicus) has been classified as Endangered on the IUCN Red List of Threatened Species (2008). Genetic diversity data provide important information for the management of captive breeding and conservation of this species. We analyzed mitochondrial control region (CR) sequences from 37 captive Asian tapirs in Thailand. Multiple alignments of the full-length CR sequences sized 1268 bp comprised three domains as described in other mammal species. Analysis of 16 parsimony-informative variable sites revealed 11 haplotypes. Furthermore, the phylogenetic analysis using median-joining network clearly showed three clades correlated with our earlier cytochrome b gene study in this endangered species. The repetitive motif is located between first and second conserved sequence blocks, similar to the Brazilian tapir. The highest polymorphic site was located in the extended termination associated sequences domain. The results could be applied for future genetic management based in captivity and wild that shows stable populations.

Black rhinoceros (Diceros bicornis) and domestic horse (Equus caballus) hindgut microflora demonstrate similar fermentation responses to grape seed extract supplementation in vitro.

The domestic horse is used as a nutritional model for rhinoceros maintained under human care. The validity of this model for browsing rhinoceros has been questioned due to high prevalence of iron overload disorder (IOD) in captive black rhinoceros (Diceros bicornis), which is associated with high morbidity and mortality. Iron chelators, such as tannins, are under investigation as dietary supplements to ameliorate or prevent IOD in prone species. Polyphenolic compounds variably affect microbial fermentation, so the first objective of this experiment was to evaluate the effects of grape seed extract (GSE; a concentrated source of condensed tannins; CT) on black rhinoceros hindgut fermentation. Equine nutrition knowledge is used to assess supplements for rhinoceros; therefore, the second objective was to evaluate the domestic horse model for black rhinoceros fermentation and compare fermentation responses to GSE using a continuous single-flow in vitro culture system. Two replicated continuous culture experiments were conducted using horse and black rhinoceros faeces as inoculum sources comparing four diets with increasing GSE inclusion (0.0%, 1.3%, 2.7% and 4.0% of diet dry matter). Diet and GSE polyphenolic compositions were determined, and sodium sulphite effect on neutral detergent fibre extraction of CT-containing forages was tested. Increasing GSE inclusion stimulated microbial growth and fermentation, and proportionally increased diet CT concentration and iron-binding capacity. Horse and black rhinoceros hindgut microflora nutrient digestibility and fermentation responses to GSE did not differ, and results supported equine fermentation as an adequate model for microbial fermentation in the black rhinoceros. Interpretation of these results is limited to hindgut fermentation and further research is needed to compare foregut digestibility and nutrient absorption between these two species. Supplementation of GSE in black rhinoceros diets up to 4% is unlikely to adversely affect hindgut nutrient digestibility or microbial viability and fermentation.

Convergence of Afrotherian and Laurasiatherian Ungulate-Like Mammals: First Morphological Evidence from the Paleocene of Morocco.

Molecular-based analyses showed that extant "ungulate" mammals are polyphyletic and belong to the two main clades Afrotheria (Paenungulata) and Laurasiatheria (Euungulata: Cetartiodactyla-Perissodactyla). However, paleontological and neontological studies hitherto failed to demonstrate the morphological convergence of African and Laurasian "ungulate" orders. They support an "Altungulata" group including the Laurasian order Perissodactyla and the African superorder Paenungulata and characterized especially by quadritubercular and bilophodont molars adapted for a folivorous diet. We report new critical fossils of one of the few known African condylarth-like mammal, the enigmatic Abdounodus from the middle Paleocene of Morocco. They show that Abdounodus and Ocepeia display key intermediate morphologies refuting the homology of the fourth main cusp of upper molars in Paenungulata and Perissodactyla: Paenungulates unexpectedly have a metaconule-derived pseudohypocone, instead of a cingular hypocone. Comparative and functional dental anatomy of Abdounodus demonstrates indeed the convergence of the quadritubercular and bilophodont pattern in "ungulates". Consistently with our reconstruction of the structural evolution of paenungulate bilophodonty, the phylogenetic analysis relates Abdounodus and Ocepeia to Paenungulata as stem taxa of the more inclusive new clade Paenungulatomorpha which is distinct from the Perissodactyla and Anthracobunidae. Abdounodus and Ocepeia help to identify the first convincing synapomorphy within the Afrotheria-i.e., the pseudohypocone-that demonstrates the morphological convergence of African and Laurasian ungulate-like placentals, in agreement with molecular phylogeny. Abdounodus and Ocepeia are the only known representatives of the early African ungulate radiation predating the divergence of extant paenungulate orders. Paenungulatomorpha evolved in Africa since the early Tertiary independently from laurasiatherian euungulates and "condylarths" such as apheliscids. The rapid early Tertiary radiation of the Afrotheria and Paenungulatomorpha, as illustrated by the Paleocene Moroccan mammals, is concurrent with that of the Laurasiatheria in a general, explosive mammal evolution in both the South and North Tethyan continents following the K/Pg event.

Osteopathology in Rhinocerotidae from 50 Million Years to the Present.

Individual elements of many extinct and extant North American rhinocerotids display osteopathologies, particularly exostoses, abnormal textures, and joint margin porosity, that are commonly associated with localized bone trauma. When we evaluated six extinct rhinocerotid species spanning 50 million years (Ma), we found the incidence of osteopathology increases from 28% of all elements of Eocene Hyrachyus eximius to 65-80% of all elements in more derived species. The only extant species in this study, Diceros bicornis, displayed less osteopathologies (50%) than the more derived extinct taxa. To get a finer-grained picture, we scored each fossil for seven pathological indicators on a scale of 1-4. We estimated the average mass of each taxon using M1-3 length and compared mass to average pathological score for each category. We found that with increasing mass, osteopathology also significantly increases. We then ran a phylogenetically-controlled regression analysis using a time-calibrated phylogeny of our study taxa. Mass estimates were found to significantly covary with abnormal foramen shape and abnormal bone textures. This pattern in osteopathological expression may reflect a part of the complex system of adaptations in the Rhinocerotidae over millions of years, where increased mass, cursoriality, and/or increased life span are selected for, to the detriment of long-term bone health. This work has important implications for the future health of hoofed animals and humans alike.

The first finding of a rhinoceros of the Genus Stephanorhinus in Arctic Asia.

The first skull of a rhinoceros of the genus Stephanorhinus has been found above the Arctic Circle on the middle Chondon River (Yakutia, Russia). This is the northernmost finding that extends significantly the genus range and provides additional information about the diet and environment of a genus representative. Plant remnants from the maxillary tooth cavities were identified as belonging to trees (Larix, Betula), shrubs (Ericaceae), mosses (Aulacomnium sp., Polytrichum sp.), herbs (Dicotyledones) and grasses (Poaceae), but not to sedges (Cyperaceae). The pattern of attrition of teeth and marks on the chewing surface enamel indicate diverse nourishment. Chondon rhinoceros lived in under Arctic-like climatic conditions, with rather limited food resources.

Phylogeography and spatial structure of the lowland tapir (Tapirus terrestris, Perissodactyla: Tapiridae) in South America.

We sequenced the mitochondrial cytochrome b gene of 141 lowland tapirs (Tapirus terrestris) - representing the largest geographical distribution sample of this species studied across of South America to date. We compare our new data regard to two previous works on population structure and molecular systematics of T. terrestris. Our data agree with the Thoisy et al.'s work in (1) the Northern Western Amazon basin was the area with the highest gene diversity levels in T. terrestris, being probably the area of initial diversification; (2) there was no clear association between haplogroups and specific geographical areas; (3) there were clear population decreases during the last glacial maximum for the different haplogroups detected, followed by population expansions during the Holocene; and (4) our temporal splits among different T. terrestris haplogroups coincided with the first molecular clock approach carried out by these authors (fossil calibration). Nevertheless, our study disagreed regard to other aspects of the Thoisy et al.'s claims: (1) meanwhile, they detected four relevant clades in their data, we put forward six different relevant clades; (2) the Amazon River was not a strong barrier for haplotype dispersion in T. terrestris; and (3) we found reciprocal monophyly between T. terrestris and T. pinchaque. Additionally, we sequenced 42 individuals (T. terrestris, T. pinchaque, T. bairdii, and the alleged "new species", T. kabomani) for three concatenated mitochondrial genes (Cyt-b, COI, and COII) agreeing quite well with the view of Voss et al., and against of the claims of Cozzuol et al. Tapirus kabomani should be not considered as a full species with the results obtained throughout the mitochondrial sequences.

Ancient collagen reveals evolutionary history of the endemic South American 'ungulates'.

Since the late eighteenth century, fossils of bizarre extinct creatures have been described from the Americas, revealing a previously unimagined chapter in the history of mammals. The most bizarre of these are the 'native' South American ungulates thought to represent a group of mammals that evolved in relative isolation on South America, but with an uncertain affinity to any particular placental lineage. Many authors have considered them descended from Laurasian 'condylarths', which also includes the probable ancestors of perissodactyls and artiodactyls, whereas others have placed them either closer to the uniquely South American xenarthrans (anteaters, armadillos and sloths) or the basal afrotherians (e.g. elephants and hyraxes). These hypotheses have been debated owing to conflicting morphological characteristics and the hitherto inability to retrieve molecular information. Of the 'native' South American mammals, only the toxodonts and litopterns persisted until the Late Pleistocene-Early Holocene. Owing to known difficulties in retrieving ancient DNA (aDNA) from specimens from warm climates, this research presents a molecular phylogeny for both Macrauchenia patachonica (Litopterna) and Toxodon platensis (Notoungulata) recovered using proteomics-based (liquid chromatography-tandem mass spectrometry) sequencing analyses of bone collagen. The results place both taxa in a clade that is monophyletic with the perissodactyls, which today are represented by horses, rhinoceroses and tapirs.

Ancient proteins resolve the evolutionary history of Darwin's South American ungulates.

No large group of recently extinct placental mammals remains as evolutionarily cryptic as the approximately 280 genera grouped as 'South American native ungulates'. To Charles Darwin, who first collected their remains, they included perhaps the 'strangest animal[s] ever discovered'. Today, much like 180 years ago, it is no clearer whether they had one origin or several, arose before or after the Cretaceous/Palaeogene transition 66.2 million years ago, or are more likely to belong with the elephants and sirenians of superorder Afrotheria than with the euungulates (cattle, horses, and allies) of superorder Laurasiatheria. Morphology-based analyses have proved unconvincing because convergences are pervasive among unrelated ungulate-like placentals. Approaches using ancient DNA have also been unsuccessful, probably because of rapid DNA degradation in semitropical and temperate deposits. Here we apply proteomic analysis to screen bone samples of the Late Quaternary South American native ungulate taxa Toxodon (Notoungulata) and Macrauchenia (Litopterna) for phylogenetically informative protein sequences. For each ungulate, we obtain approximately 90% direct sequence coverage of type I collagen α1- and α2-chains, representing approximately 900 of 1,140 amino-acid residues for each subunit. A phylogeny is estimated from an alignment of these fossil sequences with collagen (I) gene transcripts from available mammalian genomes or mass spectrometrically derived sequence data obtained for this study. The resulting consensus tree agrees well with recent higher-level mammalian phylogenies. Toxodon and Macrauchenia form a monophyletic group whose sister taxon is not Afrotheria or any of its constituent clades as recently claimed, but instead crown Perissodactyla (horses, tapirs, and rhinoceroses). These results are consistent with the origin of at least some South American native ungulates from 'condylarths', a paraphyletic assembly of archaic placentals. With ongoing improvements in instrumentation and analytical procedures, proteomics may produce a revolution in systematics such as that achieved by genomics, but with the possibility of reaching much further back in time.

Abundancia relativa, estructura poblacional, preferencia de hábitat y patrones de actividad del tapir centroamericano Tapirus bairdii (Perissodactyla: Tapiridae), en la Selva de Los Chimalapas, Oaxaca, México / Relative abundance, population structure, habitat preferences and activity patterns of Tapirus bairdii (Perissodactyla: Tapiridae), in Chimalapas forest, Oaxaca, Mexico

Baird’s tapir (Tapirus bairdii) is endangered primarily because of habitat loss and fragmentation, and overhunting throughout its distribution range. One of the priority land areas for the conservation of this species is the Northern part of its range in the Chimalapas forest, Oaxaca. The aim of this research was to determine the relative abundance, population structure, habitat preferences and activity patterns of Baird´s tapir (Tapirus bairdii) in the Chimalapas forest, Oaxaca, Mexico, through the non-invasive technique of camera-trap sampling. A total of five sampling sessions were undertaken among 2009-2013, and used a total of 30 camera-traps in each period. The determinant factor of the sampling design was the hunting between two study areas. A total sampling effort of 9 000 trap-days allowed to estimate an index of relative abundance (IRA) of 6.77 tapir photographs/1 000 trap-days (n=61). IRA varied significantly between sampling stations (Mann-Whitney, p<0.01). The frequency of Baird´s tapir photos was higher in the dry season in tropical rain forest without hunting (x², p<0.5). In the rainy season, the tropical rain forest and secondary vegetation habitats showed higher photo frequency than expected from random (x², p<0.5). Considering population structure, a 95.08% of adult animals was obtained in photographic records (n=58). Three types of activity pattern were observed, with more nocturnal records (88.33%; Kruskal-Wallis, p<0.05). The Chimalapas forest appears to be the second most important terrestrial priority ecoregion, just after the Mayan Forest (Campeche, Chiapas, Quintana Roo), for the conservation of tapir populations, not only for Mexico but also for Central America. Rev. Biol. Trop. 62 (4): 1407-1419. Epub 2014 December 01.

El tapir centroamericano (Tapirus bairdii) está en peligro de extinción debido principalmente a la pérdida y fragmentación de su hábitat, y a la cacería sin control en toda su área de distribución. Una de las regiones terrestres prioritarias para la conservación de esta especie en la zona norte de su distribución se encuentra en la Selva de los Chimalapas, Oaxaca. Por lo que el objetivo de la presente investigación fue determinar la abundancia relativa, estructura poblacional, preferencia de hábitat y patrones de actividad del tapir centroamericano (Tapirus bairdii) en la Selva de los Chimalapas, Oaxaca, México, mediante el uso de cámaras trampa. Se realizaron cinco periodos de muestreo fotográfico entre 2009 y 2013 con un total de 30 cámaras trampa en cada periodo. El factor de diseño fue la intensidad de caza entre dos sitios. Con un esfuerzo total de muestreo de 9 000 días/trampa se estimó un índice de abundancia relativa (IAR) de 6.77/1 000 trampas-noche (n=61), variando significativamente entre estaciones de muestreo (Mann-Whitney, p<0.01). Durante la temporada de secas, los tapires fueron más abundantes y utilizaron con mayor intensidad el bosque tropical perennifolio sin cacería (x², p<0.5). Mientras que en la temporada de lluvia, el bosque tropical perennifolio con cacería y la vegetación secundaria con cacería fueron los hábitat significativamente más utilizados que lo esperado (x², p<0.5). Con respecto a la estructura poblacional se obtuvo un 95.08% de registros fotográficos de animales adultos (n=58). Se registraron tres tipos de patrones de actividad para la especie, siendo el patrón nocturno el que presentó mayor porcentaje de registros; 88.33% (Kruskal-Wallis, p<0.05). Finalmente, con base al número de registros fotográficos y a los resultados obtenidos es posible considerar a la Selva de los Chimalapas como la segunda eco-región terrestre prioritaria en importancia; después de la Selva Maya (Campeche, Chiapas, Quintana Roo), en la conservación de las poblaciones de tapir centroamericano, no sólo de México, sino de Centroamérica.