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Late pleistocene vertebrates from three-forks cave, Adair county, Oklahoma Ozark highland
Abstract
We report on an assemblage of vertebrate fossils from a limestone cave in the southwestern portion of the Ozark Highland. The fauna includes several extinct large-bodied mammalian taxa including Megalonyx jeffersonii (Jefferson’s ground sloth), Canis dirus (dire wolf), Arctodus simus (short-faced bear; two individuals), and Equidae (extinct horses), which indicate a late Pleistocene age. In addition, there is a variety of extant vertebrates including a fish Aplodinotus cf. grunniens (freshwater drum), unidentified Anura (frogs and toads) and Caudata (salamanders), Terrapene sp. (box turtles), cf. Ophisaurus (legless lizards), Colubroidea and Crotalidae (non-venomous snakes and pit vipers), Bubo virginianus (great horned owl), and at least 12 other mammals. The mammals are Sorex sp. (long-tailed shrews), Perimyotis subflavus (tricolored bat), Eptesicus fuscus (big brown bat), Myotis grisescens (gray myotis), possibly other species of Myotis, Vulpini (foxes), several rodents, Geomys sp. (pocket gophers), Chaetodipus or Perognathus (pocket mice), Peromyscini (native mice), Neotoma cf. floridana (eastern wood rat), Microtus cf. ochrogaster (prairie vole), and, Sylvilagus sp. (cottontail rabbits). An earlier report provided a tentative age of one of the Arctodus simus of about 34000 years ago (late Pleistocene, Rancholabrean). Among the 23 taxa in the Three-Forks Cave assemblage, 2 species are added to the Oklahoma Ozark Highland paleofauna, freshwater drum and great horned owl. One extralimital taxon, the pocket mouse Chaetodipus or Perognathus, is present in the assemblage. Numerous remains of juvenile bats of Myotis grisescens and Eptesicus fuscus provide evidence that these species used Three-Forks Cave as a maternity site. Large crater-like pits in the floor of Three-Forks Cave and other caves in the vicinity may represent ancient and modern beds of the short-faced bear and black bear, respectively.
Aplodinotus grunniens represents one of the most common, widespread, and unique freshwater fishes in North America. Understanding the evolutionary history of this sciaenid is challenging though as published palaeontological records are lacking. Existing literature documenting skeletal remains and otoliths is summarised herein to better understand divergence and biogeography of the extant A. grunniens and extinct Aplodinotus species. Fossil evidence indicates that in addition to A. grunniens, three putative, extinct, marine species in North America and two in South America existed. The North American fossil Aplodinotus range from Oligocene to early Miocene, while the genus extends to the middle Miocene in South America. All described extinct fossil Aplodinotus have been recovered from shallow marine sediments with the oldest from the U.S.A. Gulf Coastal Plain. All sites with extant A. grunniens are from freshwater deposits ranging from middle to late Miocene to Holocene in age which very closely approximate the modern geographic distribution and include a variety of preserved skeletal elements and otoliths. The disappearance of the fossil marine Aplodinotus in the early Miocene in the Gulf is interpreted to represent the genus’ transition to brackish and eventually freshwater habitats and development of the extant species by the late Miocene.
During the late Pleistocene of North America (≈36,000 to 10,000 years ago), saber-toothed cats, American lions, dire wolves, and coyotes competed for prey resources at Rancho La Brea (RLB). Despite the fact that the giant short-faced bear (Arctodus simus) was the largest land carnivoran present in the fauna, there is no evidence that it competed with these other carnivores for prey at the site. Here, for the first time, we report carious lesions preserved in specimens of A. simus, recovered from RLB. Our results suggest that the population of A. simus from RLB was more omnivorous than the highly carnivorous populations from the Northwest. This dietary variation may be a consequence of different competitive pressures.
The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (∼10,000 to 30,000 years B.P.) leading to modern Holocene fish diversity patterns. The objective of this study was to describe the fish assemblages of the Tennessee River Basin from the late Pleistocene using a series of faunas from locales throughout the basin documented from published literature, unpublished reports, and an undocumented fauna from Bell Cave (site ACb-2, Colbert County, AL). Herein we discuss 41 unequivocal taxa from 10 late Pleistocene localities within the basin and include a systematic discussion of 11 families, 19 genera, and 24 identifiable species (28 unequivocal taxa) specific to the Bell Cave locality. Among the described fauna are several extirpated (e.g., Northern Pike
Esox lucius
, Northern Madtom
Noturus stigmosus
) and a single extinct (Harelip Sucker
Moxostoma lacerum
) taxa that suggest a combination of late Pleistocene displacement events coupled with more recent changes in habitat that have resulted in modern basin diversity patterns. The Bell Cave locality represents one of the most intact Pleistocene freshwater fish deposits anywhere in North America. Significant preservational, taphonomic, sampling, and identification biases preclude the identification of additional taxa. Overall, this study provides a detailed look into paleo-river ecology, as well as freshwater fish diversity and distribution leading up to the contemporary biodiversity patterns of the Tennessee River Basin and Mississippi River Basin as a whole.
A small quarry in Pliocene lacu strine deposits at House Mountain in the Verde Formation of central Arizona produced a high concentration of micro vertebrate fossils of early Blancan (early Pliocene) age. Within a single bedding plane on excavated blocks, a miniature (0.25 m2) bone bed was exposed piecemeal under a microscope and mapped. The deposit contained about 300 recognizable skeletal elements representing a small finch and several kinds of rodents. Concomitant screen washing of the site produced 1085 more rodent and bird bone fragments plus shrew, bat, and salamander remains. The House Mountain assemblage clearly exhibits the characteristics of nocturnal raptor (owl) pellet accumulations. Comparison with modern owl pellet accumulations in Arizona, including a quantitative consideration of bones from an area equal to that quarried for fossils showed similar partial association of the elements of individual skeletons. Weathering of bones prior to burial probably was limited to brief sub aerial exposure to rainfall and insect activity or deposition in calm, shallow water sufficient to disintegrate owl pellets but not sufficient to completely dissociate some skeletal elements of individual prey animals. A medium-sized owl (100 to 400 g) probably accumulated the House Mountain micro vertebrates. Contrary to other evidence, the age-frequency profile of extinct kangaroo rats, Prodipodomys, does not indicate attritional mortality. Had screen washing been used as the only method of recovery of fossils, much taphonomic information would have been lost. However, unless the taphonomic information for a given site is crucial or equivocal, the additional time spent on quarrying and mapping may be un warranted.
San Josecito Cave is located on a steep western flank of the Sierra Madre Oriental, Nuevo Leon, Mexico, at 2250 m elevation. A total of 1115 skeletal remains of lizards are known from the deposit; only two specimens were from previous excavations. In greater than 100,000 vertebrate remains, only four species of lizards have been recovered: one anguid (Barisia cf. B. imbricata, n = 1088 fossils) and three phrynosomatids (Phrynosoma josecitensis, n = 1; P. orbiculare, n = 1; P. cf. P orbiculare, n = 12; and Sceloporus sp., n = 13). The cave has produced the type and only known specimen of the extinct species Phrynosoma josecitensis, described from an earlier excavation. The presence of, or the validity of, this extinct species cannot be verified on the basis of remains recovered from the current excavation, and the taxon may be a variant of the locally living P. orbiculare. The first fossil record of Barisia imbricata is presented.
Chiropteran mandibles from late Pleistocene/Holocene fossil cave localities in Hamilton County were identified in order to examine changes in bat species diversity and population trends over extended periods of time, providing insight into how bats in Southeast Tennessee have responded to major environmental changes over the past 10,000-20,000 years. Generic and species identifications were based on an unpublished key developed by the authors. Measurements of alveolar length (c1-m3) and total length measurements from the symphysis to the condyle were taken for all specimens identified as members of the genus Myotis in an attempt to identify species in this genus. The results of this study failed to confirm those of previous univariate morphological studies, suggesting that multivariate morphometric analyses may be needed to establish a means to differentiate among the species in this genus. Diversity data indicated two patterns of species abundance, with Eptesicus fuscus (Big Brown Bat) dominating some sites and Myotis sp. dominating others. The data suggest, but do not conclusively demonstrate, that a temporal replacement of older Eptesicus faunas by younger, Myotis-dominated faunas has occurred, connected with post-Pleistocene global warming. In addition, a correspondence between human disturbance and bat populations levels was observed. It is very likely that human disturbance has caused bat populations to become extinct in the caves under study, reinforcing the claim of previous researchers that bat population decline is a recent phenomenon that is tightly linked to human disturbance.
Accounts of Pleistocene vertebrates cross-referenced to sites in Trans-Pecos Texas, New Mexico, Arizona, southern California, southern Nevada, Chihuahua, Sonora, and Baja California.
Little information has been published on selection of tree roosts by eastern pipistrelles (Perimyotis subflavus )i n forested environments, and no radiotelemetry-based studies have been conducted on males in forested settings. Therefore, we used radiotelemetry to characterize summer roost selection by 21 male (33 roosts) and 7 female (14 roosts) eastern pipistrelles during 6 years in a forested region of the Ouachita Mountains of Arkansas. All roosts were located in the vegetation of tree canopies; 50% of roosts of females and 91% of roosts of males were in dead leaves of deciduous trees. Three (43%) of 7 maternity colonies were in dead needles of large live pines (Pinus echinata); this is the 1st documented use of pines by this species for roosting. Males selected tree sizes randomly but females selected trees that were larger (P , 0.05) than random. For males, 87% of roosts were in oaks (Quercus), and males roosted at sites with more midstory hardwoods, more large pines in the overstory, less canopy cover, and farther from the nearest trees than random locations. In a landscape offering a diversity of forest habitats, eastern pipistrelles during summer roosted mostly in leaves of oaks in mature (� 50-year-old) forest with a relatively complex structure and a hardwood component.
The hypothesis that giant short-faced bears of the genera Agriotherium and Arctodus were primarily carnivorous and preyed on large terrestrial mammals is examined. It is argued that the shape and wear pattern of the cheek teeth and the presence of the premasseteric fossa on the mandible in these two ursids suggest a large amount of plant material in their diet. Likewise, the absence of adaptations for either ambush or pursuit predation in their skull and postcranial skeleton suggest that they did not prey on large terrestrial mammals. Further support for this conclusion is provided by a comparison of the dental and skeletal morphology of Agriotherium and Arctodus to that of Hemicyon ursinus, an extinct ursid widely accepted to have been a predaceous carnivore. However, it is also argued that the giant short-faced bears included a large amount of animal material in their diets, which was obtained by scavenging.
A mud deposit in Sassafras Cave near Stilwell, Oklahoma, produced a small assemblage of fossil vertebrates including an unidentified salamander and the mammals Myotis sp., Lasionycteris noctivagans, Pipistrellus subflavus, Tamias striatus, Peromyscus sp., Reithrodontomys sp., Microtus sp., and Tapirus veroensis. The fossiliferous mud deposit is a stream terrace containing abundant red clay accumulated behind roof fall and breakdown boulders that temporarily dammed the main stream-passage of the cave. The tapir fossils indicate a late Rancholabrean (late Pleistocene) age for the deposit. This is the first report of a tapir from the Oklahoma Ozark Highland and only the second report of Pleistocene megafauna from a cave in eastern Oklahoma. The tapir is represented by a partial skeleton with some of the distal leg bones articulated in life position in the deposit. The animal probably died while it was standing or lying in the mud, possibly after falling into the cave or walking in through an entrance that had a different configuration in the Pleistocene than the present sinkhole entrance.
One hundred DNA sequences from the mitochondrial cytochrome-b gene of 44 species of deer mice (Peromyscus (sensu stricto), 1 of Habromys, 1 of Isthmomys, 2 of Megadontomys, and the monotypic genera Neotomodon, Osgoodomys, and Podomys were used to develop a molecular phylogeny for Peromyscus. Phylogenetic analyses (maximum parsimony, maximum likelihood, and Bayesian inference) were conducted to evaluate alternative hypotheses concerning taxonomic arrangements (sensu stricto versus sensu lato) of the genus. In all analyses, monophyletic clades were obtained that corresponded to species groups proposed by previous authors; however, relationships among species groups generally were poorly resolved. The concept of the genus Peromyscus based on molecular data differed significantly from the most current taxonomic arrangement. Maximum-likelihood and Bayesian trees depicted strong support for a clade placing Habromys, Megadontomys, Neotomodon, Osgoodomys, and Podomys within Peromyscus. If Habromys, Megadontomys, Neotomodon, Osgoodomys, and Podomys are regarded as genera, then several species groups within Peromyscus (sensu stricto) should be elevated to generic rank. Isthmomys was associated with the genus Reithrodontomys; in turn this clade was sister to Baiomys, indicating a distant relationship of Isthmomys to Peromyscus. A formal taxonomic revision awaits synthesis of additional sequence data from nuclear markers together with inclusion of available allozymic and karyotypic data.
This book presents a major summary of what is currently known about North American amphibians and fossils in the Pleistocene. The only book available on the subject, it includes a general treatment of the Pleistocene and its effects on the physical and biological world, and features an illustrated bestiary of the herpetological families and genera as well as a discussion of the identification of fossils. The changes in the North American herpetofauna from the Cretaceous to the Pleistocene are cogently summarized, and complete herpetofaunal lists from the seven designated Pleistocene regions of North America are included. The concluding chapter details range adjustments and extinction patterns, and contrasts the evolutionary “stasis” of the herpetofauna with the avian and mammalian fauna. The work will be considered an essential reference for paleontologists.
We report two new late Pleistocene avifaunas from New Mexico, recovered from Sandia Cave during archaeological excavations by F. Hibben in the 1930s and the nearby Marmot Cave excavated in 2000. The fossil assemblage from Sandia Cave consists of at least 30 taxa, including seven extralimital and two extinct species, Coragyps occidentalis (extinct vulture) and Ectopistes migratorius (Passenger Pigeon). The avifauna from Marmot Cave is limited to eight taxa shared with Sandia Cave. Two new records of Gymnogyps californianus (California Condor) are reported from these sites, as well as new records of Lagopus sp. (ptarmigan), Aegolius funereus (Boreal Owl), and Micrathene whitneyi (Elf Ow1) from New Mexico. Two new radiocarbon dates on fossil G. californianus from Sandia and Marmot cave are reported at 10 795 ± 50 and 25 090 ± 220 14C years before present (B.P.), respectively. These collections provide further evidence for mixed avian communities in New Mexico during the late Pleistocene and are similar to other cave avifaunas of comparable age from the Great Basin and Rocky Mountain regions. The birds from Sandia Cave that are shared with other fossil avifaunas include species currently found in arctic tundra, boreal, and steppe habitats, as well as open, xeric communities. This collection provides additional evidence for widespread steppe-tundra, shrub, and subalpine forest environments at lower elevations of western North America during the late Pleistocene.
We investigated the effect of reproductive stage (reproductive versus non-reproductive) on summer roost use by adult female eastern pipistrelles. Due to differing selective pressures associated with summer reproductive and non-reproductive stages, we hypothesized that roost tree species and tree characteristics used by adult female eastern pipistrelles would differ depending on the individual's reproductive stage. Reproductive females preferred roost trees in the genus Quercus, whereas non-reproductive females did not prefer a specific species group. Reproductive females roosted at lower levels in the forest strata, closer to a permanent water source, and farther from the nearest forest/field edge. We stress the importance of recognizing the potential for changes in habitat use by adult female bats during summer months depending on whether individuals are reproductive or non-reproductive. Combining data from reproductive classes of adult females may mask important roost characteristics unique to maternity colonies of bats.
An Upper Pliocene population of Nekrolagus progressus (Hibbard) represented by 178 P3s from the Rexroad fauna has 11.8% of the individuals with a P3 enamel pattern that is like the Ps pattern of Sylvilagus, Caprolagus, Oryctolagus and Lepus. For the first time in the fossil record there is evidence for the time and place of the variation (mutation) within a population that produced a character of generic grade. It is proposed that this pattern developed in North America and gave rise to that now found in Sylvilagus, Caprolagus, Oryctolagus and Lepus. Cenozoic faunas of Eurasia that contain remains of Oryctolagus and Lepus are younger than the Rexroad fauna. Over 2,000 Recent Lepus, Oryctolagus and Sylvilagus dentitions were examined. Twelve Recent specimens of these three genera were found that contained the Nekrolagus pattern. The genera are quite recent in origin. These rabbits provide an excellent group for comparative study with the late Pliocene Nekrolagus to establish the rate of generic development. A phylogenetic summary is given to show the relationship of the Leporinae as based upon the development of P2 and P3.
A small Pleistocene, probably Irvingtonian, fauna collected near Curtis, Oklahoma, has yielded the first record of Nothrotheriops from Oklahoma. Examination of previously known and new specimens shows that all well-documented Rancholabrean records of this genus occur in the mountainous areas of western North America. Definite Irvingtonian occurrences span the continent from the San Francisco area and northwestern Mexico through the Great Plains to Florida. This change in distribution may have resulted from an increasingly variable late Pleistocene climate that restricted Nothrotheriops to areas where it could respond by altitudinal migration and by utilizing cave environments as thermal buffers. Continuing reduction of its range could have resulted in small disjunct mountain populations that finally succumbed to the climatic extremes of the terminal Pleistocene or hunting by paleoindians.
Palynological investigations of spring deposits were conducted as part of an interdisciplinary research effort into late Pleistocene archaeology, geology, and paleoecology of the western Missouri Ozarks. The springs, located in the Pomme de Terre River valley in Benton and Hickory Counties, Missouri, lie 400 km south of the maximum extent of the Wisconsin ice sheet on the present Great Plains-Eastern Deciduous Forest border. The valley will soon be flooded by a government impoundment. Two springs were completely excavated and three others sampled, including a spring originally excavated by Albert Koch in 1840. The pollen record, with associated plant macrofossils, is divided into three distinct zones: a lower nonarboreal pollen (NAP) and pine zone, a middle spruce- (Picea) dominated zone, and an upper zone of spruce with deciduous elements. Radiocarbon dates show that the NAP-pine zone was established prior to 40,000 BP and existed until 20,000-25,000 BP; it was deposited during the mid-Wisconsin interstade. The mid-Wisconsin interstadial vegetation of the Ozarks is interpreted as an open pine-parkland. Plant macrofossils of Pinus banksiana in this zone indicate that jack pine was present. Spruce was probably absent as no spruce macrofossils and only traces of spruce pollen were found. The associated mid-Wisconsin fauna is dominated by mastodon (Mammut americanum) with horse (Equus) and musk-ox (Symbos). With the onset of late Wisconsin full-glacial conditions, variously dated at 20,000-25,000 BP, pollen dominance shifts from NAP-pine to spruce. This is interpreted as the replacement of the pine-parkland by boreal spruce forest. Two pollen zones are apparent within the full-glacial: an older zone with up to 92% spruce pollen occurring after the transition from NAP-pine to spruce, and a younger zone with less spruce (38%) and more thermophilous deciduous tree pollen. The change to less spruce and more deciduous tree pollen apparently reflects slightly improved climatic conditions during a late phase of the full-glacial; the zone is radiocarbon dated at 16,500 BP on spruce logs. It contains abundant spruce and larch (Larix) macrofossils associated with the remains of at least 30 mastodons plus giant beaver (Castoroides), ground sloth (Paramylodon), tapir (Tapirus), deer (Odocoileus), and horse (Equus). The western Missouri Ozarks were covered by open pine-parkland from at least 40,000 BP until the start of the full-glacial 20,000-25,000 BP, then boreal spruce forest until at least 13,500 BP. Deciduous elements became more prominent in the spruce forest in its latter phase. The present oak-hickory forest developed after the decline of the spruce and is thus no older than postglacial.
Portions of an extinct giant short-faced bear, Arctodus simus, were recovered from a remote area with- in an Ozark cave, herein named Big Bear Cave. The partially articulated skeleton was found in banded silt and clay sediments near a small entrenched stream. The sediment covered and preserved skeletal ele- ments of low vertical relief (e.g., feet) in articulation. Examination of a thin layer of manganese and clay under and adjacent to some skeletal remains revealed fossilized hair. The manganese in this layer is con- sidered to be a by-product of microorganisms feeding on the bear carcass. Although the skeleton was incomplete, the recovered material represents one of the more complete skeletons for this species. The stage of epiphyseal fusion in the skeleton indicates an osteologically immature individual. The specimen is considered to be a female because measurements of teeth and fused postcranial elements lie at the small end of the size range for A. simus. Like all other bears, the giant short-faced bear is sexually dimorphic. A review of A. simus records revealed that only small individuals have been recovered from cave deposits. This association of small A. simus specimens with caves suggests that females used these subterranean shelters for denning.
We studied roosting ecology of reproductive (pregnant or lactating) adult female eastern pipistrelles (Pipistrellus subflavus) in Indiana. Nineteen bats were radiotagged and 37 roost trees identified. Pipistrelles roosted exclusively in foliage, typically in clusters of dead leaves (65%) and less often in live foliage (30%) or squirrel nests (5%). Oaks (Quereus species) were preferred as roost trees. Roost trees and height of foliage roosts were both located well below the forest canopy. Bats remained at roost trees for 6 days on average before moving to new roosts and traveled approximately 19–139 m between roost trees. This is the 1st thorough analysis of roosting habits of this common species under natural conditions.
In this study, we review the previous evidence on the paleobiology of the giant, ‘short-faced’ bear Arctodus simus (Mammalia: Carnivora: Ursidae) and contribute new ecomorphological inferences on the paleobiology of this enigmatic species. Craniodental variables are used in a comparative morphometric study across the families Felidae, Hyaenidae, Canidae, and Ursidae. Principal components analyses (PCAs) do not show an ecomorphological adaptation towards bone-cracking or hypercarnivory in the ‘short-faced’ bear. In contrast, PCAs and discriminant analyses restricted to the craniodental data set of ursids suggest close morphological resemblance between A. simus and the extant omnivorous bears. In addition, the scaling of snout length on neurocranial length in bears indicates that the face of A. simus was not particularly short. Body mass estimates obtained from major limb bone measurements reveal that A. simus specimens of around 1000 kilograms were more common than previously suspected. Scaling relationships in extant bears of limb lengths on the least width of the femoral shaft (the variable best correlated with body mass) indicate that A. simus was not as relatively long-legged as previously thought. For these reasons, although the isotopic signature of A. simus has been interpreted as evidencing that it consumed large amounts of flesh relative to some contemporary populations of Ursus arctos, our results do not support the previous views of A. simus as a fast-running super-predator or as a specialized scavenger. In contrast, the picture that emerges from this study is one of a colossal omnivorous bear whose diet probably varied according to resource availability.
Identification of Arvicoline (Microtine) rodent molars from archaeological and palaeontological sites is especially desirable because they are conspicuous, frequently recovered in quantity, often contemporaneous with occupation, good palaeoenvironmental indicators, and morphologically distinct. In many cases, the rodent taxa themselves comprised a portion of the archaeological resource base. However, inter- and intra-site comparisons are valid only when consistent, standardized taxonomic criteria have been applied. Therefore, qualitative and quantitative methods are presented to differentiate the lower first molars (m1s) of ten Arvicoline genera (and their component species where possible) that resided east of the Rocky Mountains from the early Holocene to the present. Upper second and third molars (M2 and M3) are used in specific identification within Microtus.
Arctodus simus yukonensis, the extinct northern North American short-faced bear, is represented by an immature left humerus lacking its unfused proximal epiphysis, which was recovered from a point bar on the Ikpikpuk River, Alaska (69°41′N, 154°54′W). This is the northernmost record of this bear. The specimen is dated at 27 190 ± 280 BP (Iso Trace TO-2539) on 14C analysis, which lies within the observed age distribtution of Arctodus. The individual is larger than average for the species based on the dimensions of the distal articulation, despite its immaturity, and may have been male.
Fragmentation of landscapes and the loss of species’ habitat by the expansion and intensification of human land use are major threats to global biological diversity, making it important to quantitatively characterize species’ distributions and resource requirements at multiple spatial scales. To examine the impact of landscape structure on the distribution of forest-dwelling bats, we examined the effects of these factors on the distribution and activity patterns of tri-colored bats (Perimyotis subflavus) in Nova Scotia, Canada. In Nova Scotia maternity colonies of the tri-colored bat use clumps of Usnea spp. lichen for roosting, typically in mature spruce trees. In 2005 and 2006, we used Anabats to assess tri-colored bat activity at 90 river sites in southwest Nova Scotia. The results of echolocation monitoring indicate that the tri-colored bat occurs within a minimum area of 10,020 km2. The best landscape predictor of the magnitude of tri-colored activity was non-forested land area within commuting distance of survey sites, suggesting that tri-colored bats were less active in landscapes where forests are cleared for agriculture, settlements and timber production. Therefore, this is an example of a forest-associated bat that seems to be negatively impacted by landscape practices that reduce the spatial extent of forests.
A well-preserved ungual of a pes documents the presence of Jefferson’s ground sloth (Megalonyx jeffersonii) at the end of the Wisconsinan in North Dakota. This is the 1st report of M. jeffersonii in North Dakota, and one of few records from the upper Great Plains. An accelerator mass spectrometer radiocarbon age of 11,915 6 40 years ago was obtained from the specimen, suggesting that the sloth resided in North Dakota during the Rancholabrean Land Mammal Age, just before extinction of the species. Palynological records from sites near the sloth occurrence and of the same age indicate that it resided in a cool, moist, spruce-dominated forest habitat in a riparian setting along the Missouri River. Its presence in that setting corroborates the notion that Jefferson’s ground sloth was a browsing inhabitant of gallery forests associated with rivers. It is likely that M. jeffersonii used river valleys, such as the Missouri River valley, as migration routes.
The dire wolf was an important large, late Pleistocene predator in North and South America, well adapted to preying on megaherbivores. Geographically widespread, Canis dirus is reported from 136 localities in North America from Alberta, Canada, southward and from three localities in South America (Muaco, Venezuela; Talara, Peru; and Tarija, Bolivia). The species lived in a variety of environments, from forested mountains to open grasslands and plains ranging in elevation from sea level to 2255 m (7400 feet). Canis dirus is assigned to the Rancholabrean land mammal age of North America and the Lujanian land mammal age of South America and was among the many large carnivores and megaherbivores that became extinct in North and South America near the end of the Pleistocene Epoch.
Carbon and nitrogen stable isotope analysis of fossil bone collagen reveals that Pleistocene short-faced bears (Arctodus simus) of Beringia were highly carnivorous, while contemporaneous brown bears (Ursus arctos) had highly variable diets that included varying amounts of terrestrial vegetation, salmon, and small amounts of terrestrial meat. A reconsideration of the short-faced bear's highly derived morphology indicates that they foraged as scavengers of widely dispersed large mammal carcasses and were simultaneously designed both for highly efficient locomotion and for intimidating other large carnivores. This allowed Arctodus to forage economically over a large home range and seek out, procure, and defend carcasses from other large carnivores. The isotope data and this reconstruction of Arctodus' foraging behavior refute the hypothesis that competition from brown bears was a significant factor in the extinction of short-faced bears.
Eight new AMS radiocarbon dates on giant short-faced bears (Arctodus simus) from the contiguous United States are reported, and previously published dates from across North America are reviewed and discussed. The dates deemed to be most reliable are on purified collagen samples, and these serve as the basis for interpreting the late Pleistocene chronology and extinction of the species. The oldest acceptable radiocarbon date from the lower forty-eight states is 34,080 ± 480 BP from Island Ford Cave, Virginia, and the youngest is the previously reported 9630 ± 60 BP date from Bonner Springs, Kansas. An additional date of 10,921 ± 50 BP on the same Kansas specimen indicates a precision problem in the age of this individual. Regardless of this anomaly, new AMS dates of ∼10,800–11,000 BP on A. simus confirm that it existed up to the Pleistocene/Holocene transition and may have been one of the last megafaunal species to go extinct in North America. Further, these dates solidify the co-existence of these massive bears with humans of the Clovis cultural complex.
Late Wisconsinan micromammal faunas collected from caves in southeastern North America are characterized by nearly twice the number of species than are present in the region today. It has been proposed that this richness was achieved by paleoenvironments that permitted both the immigration and intermingling of boreal, steppe, and sub-tropical taxa with the present day deciduous forest micromammal community. Contemporaneity of component taxa cannot be assumed without ¹⁴C dating because taphonomic processes can produce similar configurations. If ‘non-analog’ specimens are contemporaneous, they represent communities with no modern analogs. If the dates on component species are disjunct, they are an artifact of time averaging and the species have a different paleoecological significance. The question remains: What is a significant interval of time to assert a community versus a time-averaging interpretation for Pleistocene faunal configurations?
Typescript. Thesis (M.S.)--University of Florida. Vita. Includes bibliographical references (leaves 315-326).
Biodiversity Response to Climate Change in the Middle Pleistocene: The Porcupine Cave Fauna from Colorado: Berkeley
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Bell, C.J., Head, J.J., and Mead, J.I., 2004, Synopsis of the herpetofauna from Porcupine Cave, in Barnosky, A.D., ed., Biodiversity Response
to Climate Change in the Middle Pleistocene: The Porcupine Cave Fauna from Colorado: Berkeley, University of California Press, p. 117−126.
https://doi.org/10.1525/california/9780520240827.003.0019; https://doi.org/10.1525/california/9780520240827.003.0011.
Summer foraging and roosting behaviour of an eastern pipistrelle, Pipistrellus subflavus: Bat Research News
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Carter, T., Menzel, M., Chapman, B., and Miller, K., 1999, Summer foraging and roosting behaviour of an eastern pipistrelle, Pipistrellus subflavus: Bat Research News, v. 40, p. 5−6.
Techniques for recovery and preparation of microvertebrate fossils: Norman, Oklahoma Geological Survey Special Publication 96-4
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Cifelli, R.L., 1996, Techniques for recovery and preparation of microvertebrate fossils: Norman, Oklahoma Geological Survey Special Publication
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Dire wolf in the Pleistocene of Oklahoma: Norman, Oklahoma Geological Survey Notes
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