| extinction of harrington's mountain goat. | keratinous horn sheaths of the extinct harrington's mountain goat, oreamnos harringtoni, were recovered at or near the surface of dry caves of the grand canyon, arizona. twenty-three separate specimens from two caves were dated nondestructively by the tandem accelerator mass spectrometer (tams). both the tams and the conventional dates indicate that harrington's mountain goat occupied the grand canyon for at least 19,000 years prior to becoming extinct by 11,160 +/- 125 radiocarbon years before ... | 1986 | 16593655 |
| evolutionary diversity of bile salts in reptiles and mammals, including analysis of ancient human and extinct giant ground sloth coprolites. | bile salts are the major end-metabolites of cholesterol and are also important in lipid and protein digestion and in influencing the intestinal microflora. we greatly extend prior surveys of bile salt diversity in both reptiles and mammals, including analysis of 8,000 year old human coprolites and coprolites from the extinct shasta ground sloth (nothrotherium shastense). | 2010 | 20444292 |
| nuclear gene sequences from a late pleistocene sloth coprolite. | the determination of nuclear dna sequences from ancient remains would open many novel opportunities such as the resolution of phylogenies, the sexing of hominid and animal remains, and the characterization of genes involved in phenotypic traits. however, to date, single-copy nuclear dna sequences from fossils have been determined only from bones and teeth of woolly mammoths preserved in the permafrost. since the best preserved ancient nucleic acids tend to stem from cold environments, this has l ... | 2003 | 12842016 |
| death of american ground sloths. | organic remains, especially dung, of extinct ground sloths provide ideal material for radiocarbon dating. rampart cave, arizona, revealed periodic occupation at intervals by the shasta ground sloth from before 40,000 years ago until 11,000 years ago. dates from other caves in the arid southwest indicate that the shasta ground sloth disappeared at very soon after the time of clovis big game hunters. ground sloth remains in south america are slightly younger. the timing of ground sloth extinction ... | 1974 | 17833721 |
| molecular coproscopy: dung and diet of the extinct ground sloth nothrotheriops shastensis. | dna from excrements can be amplified by means of the polymerase chain reaction. however, this has not been possible with ancient feces. cross-links between reducing sugars and amino groups were shown to exist in a pleistocene coprolite from gypsum cave, nevada. a chemical agent, n-phenacylthiazolium bromide, that cleaves such cross-links made it possible to amplify dna sequences. analyses of these dna sequences showed that the coprolite is derived from an extinct sloth, presumably the shasta gro ... | 1998 | 9665881 |
| a molecular analysis of ground sloth diet through the last glaciation. | dna was extracted from five coprolites, excavated in gypsum cave, nevada and radiocarbon dated to approximately 11 000, 20 000 and 28 500 years bp. all coprolites contained mitochondrial dna sequences identical to a dna sequence determined from a bone of the extinct ground sloth nothrotheriops shastensis. a 157-bp fragment of the chloroplast gene for the large subunit of the ribulosebisphosphate carboxylase (rbcl) was amplified from the boluses and several hundred clones were sequenced. in addit ... | 2000 | 11123610 |
| past and ongoing shifts in joshua tree distribution support future modeled range contraction. | the future distribution of the joshua tree (yucca brevifolia) is projected by combining a geostatistical analysis of 20th-century climates over its current range, future modeled climates, and paleoecological data showing its response to a past similar climate change. as climate rapidly warmed approximately 11 700 years ago, the range of joshua tree contracted, leaving only the populations near what had been its northernmost limit. its ability to spread northward into new suitable habitats after ... | 2011 | 21516893 |