Papers by Robert S. Feranec
51st Annual Northeastern GSA Section Meeting, 2016
Geological Society of America eBooks, Nov 14, 2018
The living tree sloths Choloepus and Bradypus are the only remaining members of Folivora, a major... more The living tree sloths Choloepus and Bradypus are the only remaining members of Folivora, a major xenarthran radiation that occupied a wide range of habitats in many parts of the western hemisphere during the Cenozoic, including both continents and the West Indies. Ancient DNA evidence has played only a minor role in folivoran systematics, as most sloths lived in places not conducive to genomic preservation. Here we utilize collagen sequence information, both separately and in combination with published mitochondrial DNA evidence, to assess the relationships of tree sloths and their extinct relatives. Results from phylogenetic analysis of these datasets differ substantially from morphology-based concepts: Choloepus groups with Mylodontidae, not Megalonychidae; Bradypus and Megalonyx pair together as megatherioids, while monophyletic Antillean sloths may be sister to all other folivorans. Divergence estimates are consistent with fossil evidence for mid-Cenozoic presence of sloths in the West Indies and an early Miocene radiation in South America
Geological Society of America Abstracts with Programs, 2020
The Ivory Pond Mastodon (Mammut americanum) was found in South Egremont, Massachusetts, in 1982. ... more The Ivory Pond Mastodon (Mammut americanum) was found in South Egremont, Massachusetts, in 1982. A recent AMS radiocarbon assay on bone collagen yielded an age of 11,885 ± 30 rcbp (UCIAMS 193953), which currently calibrates to 13,580–13,770 cal BP. This date is statistically similar to a much more imprecise date (GX9024-G; 11,440 ± 655 rcbp; 11,500–15,290 cal BP) previously obtained from the specimen. This age is similar to those of other American Mastodon specimens; collectively, these dates imply prior expansion of boreal forest (mastodon habitat) into the region ca. 14,600 cal BP. The location of this specimen east of the Hudson River implies that Late Glacial proglacial lakes that occupied the Hudson River Valley in the past were not a hindrance to megafaunal colonization of New England. The chronology and depositional contexts of this and other mastodon specimens in the region necessitate that human predation be considered as a possible cause of the extinction of this and other...
Evolutionary Ecology Research, 2017
Background: C4 grasses were not abundant in North America during the middle Miocene (c. 15 Ma). T... more Background: C4 grasses were not abundant in North America during the middle Miocene (c. 15 Ma). They did not become abundant until around 7 Ma. One can analyse stable carbon (δC) and oxygen (δO) isotope values in the enamel of fossil horse teeth to determine the extent to which horses were eating C4 grasses even during the period before those grasses became abundant. Questions: In southern California, what proportion of a middle Miocene horse’s diet was made up of C4 grasses? Was the amount enough to influence the size and shape of horse teeth? Organisms: Eighty-five specimens of five fossil horse species – Acritohippus stylodontus, Archaeohippus mourningi, Merychippus californicus, Scaphohippus intermontanus, and Scaphohippus sumani – from the middle Miocene (c. 16 Ma) of southern California (i.e. Barstow Formation, Cajon Valley Formation, and Temblor Formation). Methods: To determine if C4 grasses were present in middle Miocene horse diets, we analysed stable carbon (δC) and oxyge...
Where the Land Meets the Sea, 2017
PeerJ, 2020
Domestic cats preying on wildlife is a frequent conservation concern but typical approaches for a... more Domestic cats preying on wildlife is a frequent conservation concern but typical approaches for assessing impacts rely on owner reports of prey returned home, which can be biased by inaccurate reporting or by cats consuming prey instead of bringing it home. Isotopes offer an alternative way to quantify broad differences in animal diets. By obtaining samples of pet food from cat owners we predicted that we would have high power to identify cats feeding on wild birds or mammals, given that pet food is thought to have higher C isotope values, due to the pervasive use of corn and/or corn by-products as food ingredients, than native prey. We worked with citizen scientists to quantify the isotopes of 202 cat hair samples and 239 pet food samples from the US and UK. We also characterized the isotopes of 11 likely native prey species from the southeastern US and used mixing models to assess the diet of 47 cats from the same region. Variation in C and N isotope values for cat food was very h...
Journal of Archaeological Science: Reports, 2018
Archaeological evidence, including riverine and lake settlements, as well as fishing and netting ... more Archaeological evidence, including riverine and lake settlements, as well as fishing and netting artifacts, suggests that there was an increased reliance on inland fisheries during the mid-Holocene (ca. 4500-1800 cal BP) in northeastern North America. Unfortunately, more direct lines of evidence investigating this idea have not been thoroughly examined due to several factors, including inconsistent excavation techniques, and limitations in destructive analysis of human material remains. Here, we measured stable carbon and nitrogen isotope values from one human female and fifteen terrestrial and aquatic faunal taxa from deposits within the mid-Holocene site, Dutchess Quarry Cave 1 (Orange County, NY), to assess dietary source proportions and determine whether anadromous fish were a prominent dietary component for this individual. Using cluster analysis, potential prey species were grouped into three sources consistent with anadromous fish ("prey 1"), carnivores and omnivores ("prey 2"), and terrestrial herbivores and game birds ("prey 3"). We evaluated the relative contributions of the stable isotope values of the three prey groups using Bayesian analysis with MixSIAR. Our results indicate that animals within prey 3 made up the largest component of this individual's diet, implying that terrestrial herbivores and game birds likely dominated her diet. Fauna from isotope groups prey 1 (anadromous fish) and 2 (carnivores and omnivores) supplemented the diet. Based on these data, it appears that anadromous fish were a seasonal component of human diet and that the incorporation of these resources did not involve the dramatic reduction of other year-round protein sources.
Radiocarbon, 2018
ABSTRACTExcavations at several locations in Verteba Cave have uncovered a large amount of human s... more ABSTRACTExcavations at several locations in Verteba Cave have uncovered a large amount of human skeletal remains in association with faunal bones and Tripolye material culture. We aim to establish radiocarbon (14C) dates for eight sites and to evaluate whether these deposits are singular events, or slow accumulations over time.14C measurements, along with stable carbon and nitrogen isotope data from human and faunal remains, were collected from 18 specimens. Stable isotope values were used to evaluate human and animal diet, and whether freshwater reservoir effects offset measured dates. We found diets of the sampled species had limited to no influence from freshwater resources. Human diet appears to be dominated by terrestrial plants and herbivores. Four new sites were identified as Eneolithic. Comparisons of dates from top and bottom strata for two sites (7 and 20) reveal coeval dates, and we suggest that these deposits represent discrete events rather than slow continuous use. Las...
Radiocarbon, 2009
New dates obtained from the bone collagen of mammals from the deposits in Potter Creek Cave, Shas... more New dates obtained from the bone collagen of mammals from the deposits in Potter Creek Cave, Shasta County, California, USA, show that these fossils were emplaced over the last 30,000 yr. The dates support the assignment of the fauna in the cave to the late Pleistocene and are contemporaneous to the dates obtained from the fauna of Samwel Cave located 5 km to the north. These new dates do not support previous radiocarbon dates suggesting a Holocene extinction of the extinct bovid Euceratherium collinum, and demonstrate that this and other megafauna were not present in the vicinity after the terminal Pleistocene.
PloS one, 2015
Laser ablation of tooth enamel was used to analyze stable carbon isotope compositions of teeth of... more Laser ablation of tooth enamel was used to analyze stable carbon isotope compositions of teeth of hominins, red deer, and bears from middle Pleistocene sites in the Sierra de Atapuerca in northern Spain, to investigate the possibility that this technique could be used as an additional tool to identify periods of physiological change that are not detectable as changes in tooth morphology. Most of the specimens were found to have minimal intra-tooth variation in carbon isotopes (< 2.3‰), suggesting isotopically uniform diets through time and revealing no obvious periods of physiological change. However, one of the two sampled hominin teeth displayed a temporal carbon isotope shift (3.2‰) that was significantly greater than observed for co-occurring specimens. The δ13C value of this individual averaged about -16‰ early in life, and -13‰ later in life. This isotopic change occurred on the canine crown about 4.2 mm from the root, which corresponds to an approximate age of two to four ...
Palaeogeography, Palaeoclimatology, Palaeoecology, 2010
Stable carbon and oxygen isotope analyses of mammalian carnivoran and herbivore species from the ... more Stable carbon and oxygen isotope analyses of mammalian carnivoran and herbivore species from the late Pleistocene Valdegoba cave site in northern Spain imply competition and partitioning in resource use. In general, the data support the previously recognized ecology for the analyzed species. δ13C values show that the ecosystem around the cave was dominated by C3 plants. The observed δ18O values are similar to what is found in modern environments. The analyzed bovids, Bos primigenius, Capra pyrenaica, and ...
Analysis of the saber-tooth morphology within the Felidae indicates that canines of various saber... more Analysis of the saber-tooth morphology within the Felidae indicates that canines of various saber-toothed species grow differently. Stable oxygen isotopes analyzed from tooth enamel reveal that the scimitar-toothed Homotherium serum, which possessed short, broad sabers, had tooth crown growth rates similar to modern lions. This contrasts with the longer and thinner, dirk-toothed saber species in the genus Smilodon, S. gracilis and S. fatalis, which had much faster growth rates. With a more rapid growth rate, Smilodon reduced the total duration of crown growth to a period of time similar to that observed in modern lions, even though its tooth crown was twice as large. While comparable in overall morphology, developmental differences may reflect ecological differences among taxa bearing saber-toothed canines.
Paleobiology, 2014
Within ancient ecosystems, it is generally difficult to determine the specific diets of species f... more Within ancient ecosystems, it is generally difficult to determine the specific diets of species from higher trophic levels, which in turn hinders our understanding of trophic relationships and energy flow through these systems. To better understand the ecology of taxa at higher trophic levels, we used analysis of tooth enamel stable carbon isotope values to infer the dietary preferences of Canis edwardii and Smilodon gracilis from the Leisey Shell Pit 1A (LSP 1A) and Inglis 1A, two Pleistocene localities in Florida. The goals of the analyses were to (1) determine whether these carnivorans specialized in particular prey types or maintained a generalist diet; (2) ascertain whether carbon isotope values support what was previously suggested about the ecology of these species; and (3) establish what ecological details of ancient food webs can be discovered by carbon isotope analyses at higher trophic levels. Results show that the sampled carnivoran carbon isotope values are distributed ...
Paleobiology, 2003
Morphological adaptations may indicate increased specialization (narrowing of ecological niche) o... more Morphological adaptations may indicate increased specialization (narrowing of ecological niche) or expansion of the suite of lifestyles available to an organism (increasing niche breadth). Hypsodonty in mammals generally has been interpreted as a specialization into a grazing niche from a browsing niche. Here I examine the feeding strategy of the extinct hypsodont camel Hemiauchenia through an analysis of stable carbon isotope values from its tooth enamel, which was used to clarify its feeding strategy and to resolve conflicting interpretations of dental versus muzzle attributes. The paleodiet of Hemiauchenia is then used to test whether hypsodonty correlates to grazing within fossil Lamini. This study focuses on fossils from Florida, which is geographically ideal because unlike other regions of the country almost all extant plants on which animals browse use the C 3 photosynthetic pathway. In contrast, most of the grasses and sedges utilized by grazers use the C 4 photosynthetic pathway. If Hemiauchenia was an obligate grazer, the stable carbon isotope values of tooth enamel should reflect primarily a diet of C 4 grass and sedge (ϾϪ1.3‰). If Hemiauchenia was mainly a browser, the isotopic value should be considerably more negative reflecting ingestion primarily of C 3 browse (ϽϪ7.9‰). The mean ␦ 13 C values for Hemiauchenia during each time interval average more negative than Ϫ8.0‰, indicating a dominantly C 3 browse diet, and there is no evidence for abandonment of the browsing niche from the Hemphillian through the Rancholabrean North American Land Mammal Ages. However, an increase in the range of isotopic values indicates a diet with a higher proportion of C 4 grasses and sedges through time. This study therefore suggests that Hemiauchenia was a hypsodont intermediate feeder with preference for browse during the past 5 million years. Hypsodonty is not strictly associated with obligate grazing; instead it may, in this case, represent an adaptation to widen niche breadth that allowed grazing as well as browsing.
Paleobiology, 2006
Stable isotope analysis of mammalian tooth enamel is a valuable method for examining resource par... more Stable isotope analysis of mammalian tooth enamel is a valuable method for examining resource partitioning in modern and ancient environments where there is a mixture of C 3 and C 4 plants. However, before 7 Ma North American ecosystems were composed predominantly of C 3 plants, complicating isotopic assessment of resource partitioning. Study of modern African and North American ecosystems has shown that niche partitioning among mammals may be discerned in communities dominated by C 3 plants, suggesting that a similar approach may work for ancient C 3 ecosystems. Here, such analyses are applied to explore resource use and niche partitioning in two ancient C 3-dominated communities, one from California and one from Florida. Each locality, Black Hawk Ranch (California) and the Love Bone Bed (Florida), occurs in Miocene deposits that accumulated prior to the rapid increase in C 4 ecosystems 7 Myr ago. ␦ 13 C and ␦ 18 O values were obtained from the tooth enamel of eight species from Black Hawk Ranch, and 15 species from the Love Bone Bed. Results from the 197 bulk isotope samples showed significant differences in ␦ 13 C among taxa at the Love Bone Bed, but no significant differences were observed among taxa at Black Hawk Ranch. At both localities, equids generally have more positive ␦ 13 C values than co-occurring taxa, suggesting that equids occupied more open habitats, whereas antilocaprids, camelids, and proboscideans have more negative values, implying utilization of more closed communities. One result of note is the positive ␦ 13 C values of Pediomeryx (Yumaceras) hamiltoni from the Love Bone Bed, which suggests that P. (Y.) hamiltoni incorporated abundant fiber, possibly grass, in the diet similar to the horses from this locality. The lack of significant differences among taxa at Black Hawk Ranch may indicate a relatively homogeneous flora, or presence of abundant resources permitting niche overlap, whereas the opposite is implied by the presence of significantly different isotope values among taxa at the Love Bone Bed. The results from this study highlight the utility of isotopic techniques allowing discernment of resource partitioning in C 3-dominated landscapes such as those that persisted for the millions of years before the rapid increase in C 4 ecosystems that occurred during the late Miocene.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2004
The large size of canines in saber-toothed cats suggests implicitly that they took longer to grow... more The large size of canines in saber-toothed cats suggests implicitly that they took longer to grow than ''normal'' canines. If this were the case, then juveniles may not have been able to use them for hunting. Consequently, juvenile Smilodon fatalis, for example, may have had to remain in a social group and be fed by adults longer than is the case for modern large cats. Analysis of the stable carbon and oxygen isotope ratios within the enamel of the sabertooth provides a reasonably direct method to determine development and growth. Variation in the oxygen isotope ratios during the ontogeny of a particular tooth has been reported in many animals, and has been shown to correlate with temperature variation related to seasonality. Variation in the carbon isotope ratios typically reflects differences in diet, and can be used to determine if a carnivore preferred a prey that ate predominantly C 3 or C 4 plants. This study analyzed stable carbon and oxygen (d 13 C, d 18 O) isotope ratios from sequential, closely spaced samples of enamel carbonate obtained from upper canines of S. fatalis. A sequential change in d 18 O through canine ontogeny for two specimens (which averaged approximately À 4x) is consistent with nearly 1 year being sampled. The results suggest that the canines of S. fatalis grew about 80 mm during a 12-month period, or about 7 mm/month, and the total duration of growth for this species was about 18 months. S. fatalis apparently achieved its long canine by combining the canine development strategies of extant lions and tigers: a quick growth rate, and growth over a long time. Mean carbon isotope values of À 10.1xand À 11.3x suggest consumption of animals eating a C 3 diet.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2007
Resource use and niche partitioning has rarely been shown in ancient C3-dominated environments th... more Resource use and niche partitioning has rarely been shown in ancient C3-dominated environments through analysis of stable isotope values, even though before 7 million years ago worldwide environments were predominantly composed of C3 plant taxa. This study explores whether the analysis of stable carbon isotopes from ungulate tissues can accurately identify resource use and niche partitioning in a modern C3-dominated ecosystem in North America, in order to lay the groundwork for application to more ancient ...
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Papers by Robert S. Feranec