Thomas W. Stafford Jr.

• Ph.D.
• Researcher at Stafford Research

With the excuse of writing a critique to Domínguez-Rodrigo et al. (2021, duly replied here: Domínguez-Rodrigo & Baquedano, 2022), Holcomb et al. (this volume) intend to deny the proposal that the Arroyo del Vizcaíno (AdV, Fariña et al. 2014) is a site with evidence of human presence in South America before the LGM. Among the flaws of their critique...

All but one of the published radiocarbon dates from the 1991–1992 excavations of Strata 3 and 2 at le Trou Magrite are considered too recent because the dating was done with then-standard chemical pretreatment protocols. This study re-dates Stratum 2 using the same, then-pioneering, XAD-2 purification method on bone collagen as had been used for th...

Abstract The Chauvet‐Pont‐d'Arc Cave (Ardèche, France) contains some of the oldest Paleolithic paintings recorded to date, as well as thousands of bones of the extinct cave bear, and some remains and footprints of other animals. As part of the interdisciplinary research project devoted to this reference cave site, we analyzed a coprolite collected...

Calibrating human population dispersals across Earth’s surface is fundamental to assessing rates and timing of anthropogenic impacts and distinguishing ecological phenomena influenced by humans from those that were not. Here, we describe the Hartley mammoth locality, which dates to 38,900–36,250 cal BP by AMS ¹⁴C analysis of hydroxyproline from bon...

Hall's Cave, Texas, contains a radiocarbon dated sediment record extending from the Last Glacial Maximum through the Holocene. Changes in the characteristics of the sediments and the pattern of sedimentation in the cave correlate with environmental and climatic shifts over the last 20,000 years. The sediments in Hall's Cave preserve well-documented...

The extinct ‘Gomphotheriidae’ is the only proboscidean family that colonised South America. The phylogenetic position of the endemic taxa has been through several revisions using morphological comparisons. Morphological studies are enhanced by palaeogenetic analyses, a powerful tool to resolve phylogenetic relationships; however, aDNA preservation...

Thirty-two radiocarbon ages on bone, charcoal, and carbonized plant remains from 10 Clovis sites range from 11,110 ± 40 to 10,820 ± 10 14 C years before the present (yr B.P.). These radiocarbon ages provide a maximum calibrated (cal) age range for Clovis of ~13,050 to ~12,750 cal yr B.P. This radiocarbon record suggests that Clovis first appeared a...

Large-scale changes in global climate at the end of the Pleistocene significantly impacted ecosystems across North America. However, the pace and scale of biotic turnover in response to both the Younger Dryas cold period and subsequent Holocene rapid warming have been challenging to assess because of the scarcity of well dated fossil and pollen rec...

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...

In this study, we explore the Late Pleistocene (LP) vertebrate faunal diversity in southeastern Lesser Caucasus based on morphological and genetic identification of fossil bones from Karin Tak cave. For the first time in this under-studied region, we used a bulk bone metabarcoding genetic approach to complement traditional morphology-based taxonomi...

The extinction of Pleistocene megafauna and the role played by humans have been subjects of constant debate in American archeology. Previous evidence from the Pampas region of Argentina suggested that this environment might have provided a refugium for the Holocene survival of several megamammals. However, recent excavations and more advanced accel...

Found in 1968, the archaeological site of Anzick, Montana, contains the only known Clovis burial. Here, the partial remains of a male infant, Anzick-1, were found in association with a Clovis assemblage of over 100 lithic and osseous artifacts—all red-stained with ochre. The incomplete, unstained cranium of an unassociated, geologically younger ind...

Paisley Caves in Oregon has become well known due to early dates, and human presence in the form of coprolites, found to contain ancient human DNA. Questions remain over whether the coprolites themselves are human, or whether the DNA is mobile in the sediments. This brief introduces new research applying an integrated analytical approach combining...

Background The European bison (Bison bonasus), now found in Europe and the Caucasus, has been proposed to originate either from the extinct steppe/extant American bison lineage or from the extinct Bison schoetensacki lineage. Bison schoetensacki remains are documented in Eurasian Middle Pleistocene sites, but their presence in Upper Pleistocene sit...

The karst systems of the Yucatan Peninsula, most of them submerged, have long held the potential for Pleistocene aged fossil deposits. Since the late 1980s, cave diving explorers have been mapping these systems and, in the course of their work, discovering the remains of animals and humans. Although most of the human remains have been from the Maya...

Stone tools and mastodon bones occur in an undisturbed geological context at the Page-Ladson site, Florida. Seventy-one radiocarbon ages show that ~14,550 calendar years ago (cal yr B.P.), people butchered or scavenged a mastodon next to a pond in a bedrock sinkhole within the Aucilla River. This occupation surface was buried by ~4 m of sediment du...

Recent studies connecting the decline of large predators and consumers with the disintegration of ecosystems often overlook that this natural experiment already occurred. As recently as 14 ka, tens of millions of large-bodied mammals were widespread across the American continents. Within 1000 yr of the arrival of humans, ∼80% were extinct including...

How and when the Americas were populated remains contentious. Using ancient and modern genome-wide data, we find that the ancestors of all present-day Native Americans, including Athabascans and Amerindians, entered the Americas as a single migration wave from Siberia no earlier than 23 thousand years ago (KYA), and after no more than 8,000-year is...

Significance A cosmic impact event at ∼12,800 Cal B.P. formed the Younger Dryas boundary (YDB) layer, containing peak abundances in multiple, high-temperature, impact-related proxies, including spherules, melt glass, and nanodiamonds. Bayesian statistical analyses of 354 dates from 23 sedimentary sequences over four continents established a modeled...

How and when the Americas were populated remains contentious. Using ancient and modern genome-wide data, we found that the ancestors of all present-day Native Americans, including Athabascans and Amerindians, entered the Americas as a single migration wave from Siberia no earlier than 23 thousand years ago (ka) and after no more than an 8000-year i...

Kennewick Man, referred to as the Ancient One by Native Americans, is a male human skeleton discovered in Washington state (USA) in 1996 and initially radiocarbon-dated to 8,340-9,200 calibrated years before present (bp). His population affinities have been the subject of scientific debate and legal controversy. Based on an initial study of cranial...

Despite the abundance of fossil remains for the extinct steppe bison (Bison priscus), an animal that was painted and engraved in numerous European Paleolithic caves, a complete mitochondrial genome sequence has never been obtained for this species. In the present study we collected bone samples from a sector of the Trois-Frères Paleolithic cave (Ar...

The recent discovery that DNA methylation survives in fossil material provides an opportunity for novel molecular approaches in palaeogenomics. Here, we apply to ancient DNA extracts the probe-independent Methylated Binding Domains (MBD)-based enrichment method, which targets DNA molecules containing methylated CpGs. Using remains of a Palaeo-Eskim...

Bones from extinct Australian marsupials found at Spring Creek, Victoria, and in the Mowbray Swamp, Tasmania, have yielded scattered and anomalously young radiocarbon ages measured on collagen, gelatin or ultrafiltered gelatin. We resampled previously dated material from those two sites and from Mt Cripps, Tasmania, as well as a control sample from...

Fell's Cave lies near the Magellan Straits of South America's Southern Cone. This was the first site to provide evidence of a late Pleistocene occupation of South America, and it is the site where the Fishtail projectile point type was defined. Previous radiocarbon ages from Fell's Cave on charcoal samples from three hearths in the late Pleistocene...

Between 1500 and 1850, more than 12 million enslaved Africans were transported to the New World. The vast majority were shipped from West and West-Central Africa, but their precise origins are largely unknown. We used genome-wide ancient DNA analyses to investigate the genetic origins of three enslaved Africans whose remains were recovered on the C...

Significance Archaeological discoveries at Wally’s Beach, Canada, provide the only direct evidence of horse and camel hunting in the Americas at the end of the last Ice Age. Here, seven horses and one camel were attacked and butchered near a river crossing by prehistoric hunters. New radiocarbon dates revise the age of these kill and butchering loc...

A partial skeleton of the extinct ground sloth, Megalonyx jeffersonii, recovered from a farm near Millersburg, Ohio in 1890, was radiocarbon dated for the first time. The ungual dated is part of a skeleton mounted for exhibit at the Orton Geological Museum at Ohio State University and was the first mounted skeleton of this animal. From its initial...

Kennewick Man, referred to as the Ancient One by Native Americans, is a male human skeleton discovered in Washington state (USA) in 1996 and initially radiocarbon dated to 8,340-9,200 calibrated years before present (BP). His population affinities have been the subject of scientific debate and legal controversy. Based on an initial study of cranial...

A major cosmic-impact event has been proposed at the onset of the Younger Dryas (YD) cooling episode at ≈12,800 ± 150 years before present, forming the YD Boundary (YDB) layer, distributed over >50 million km2 on four continents. In 24 dated stratigraphic sections in 10 countries of the Northern Hemisphere, the YDB layer contains a clearly defined...

Arctic genetics comes in from the cold Despite a well-characterized archaeological record, the genetics of the people who inhabit the Arctic have been unexplored. Raghavan et al. sequenced ancient and modern genomes of individuals from the North American Arctic (see the Perspective by Park). Analyses of these genomes indicate that the Arctic was co...

The Paleoindian Goshen complex occurs in the northern Plains and eastern Rocky Mountains. Since its identification, there has been much discussion about the chronological placement of the Goshen complex. This is especially true because diagnostic Goshen projectile points occur stratigraphically below Folsom artifacts at two sites, and early dates f...

Mastodon remains dated to 22,760 RCYBP were recovered with a bifacial laurel leaf knife from 250 ft below sea level on the outer continental shelf of Virginia. This chapter reports the results of our research concerning this find and an on-going survey of the extensive archaeological collections of the Smithsonian and other repositories including l...

Because of differences in craniofacial morphology and dentition between the earliest American skeletons and modern Native Americans, separate origins have been postulated for them, despite genetic evidence to the contrary. We describe a near-complete human skeleton with an intact cranium and preserved DNA found with extinct fauna in a submerged cav...

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

Clovis, with its distinctive biface, blade and osseous technologies, is the oldest widespread archaeological complex defined in North America, dating from 11,100 to 10,700 (14)C years before present (bp) (13,000 to 12,600 calendar years bp). Nearly 50 years of archaeological research point to the Clovis complex as having developed south of the Nort...

The origins of the First Americans remain contentious. Although Native Americans seem to be genetically most closely related to east Asians, there is no consensus with regard to which specific Old World populations they are closest to. Here we sequence the draft genome of an approximately 24,000-year-old individual (MA-1), from Mal'ta in south-cent...

Interdisciplinary research at the Arlington Springs Site, Santa Rosa Island, California

Human exploitation of marine ecosystems is more recent in oceanic than near shore regions, yet our understanding of human impacts on oceanic food webs is comparatively poor. Few records of species that live beyond the continental shelves date back more than 60 y, and the sheer size of oceanic regions makes their food webs difficult to study, even i...

The Paisley Caves are the most widely accepted (by professional archaeologists) pre-Clovis site in North America. This is primarily because the directly radiocarbon-dated artifacts found with extinct megafaunal remains (horse, camel, llama, mammoth/mastodon, reindeer, and American lion) are human coprolites from which ancient dna (Pleistocene haplo...

In the Hawaiian Islands, human colonization, which began approximately 1,200 to 800 years ago, marks the beginning of a period in which nearly 75% of the endemic avifauna became extinct and the population size and range of many additional species declined. It remains unclear why some species persisted whereas others did not. The endemic Hawaiian pe...

The Paisley Caves in Oregon record the oldest directly dated human remains (DNA) in the Western Hemisphere. More than 100 high-precision radiocarbon dates show that deposits containing artifacts and coprolites ranging in age from 12,450 to 2295 14C years ago are well stratified. Western Stemmed projectile points were recovered in deposits dated to...

In the early 20th century, human skeletal remains were excavated from the Vero Beach site in southeastern Florida in direct stratigraphic association with extinct late Pleistocene mammals, including giant ground sloths, armadillos, carnivores, camels, tapirs, and horses. Despite the demonstrable stratigraphic context, prominent scientists during th...

We used high-sensitivity, high-resolution tandem mass spectrometry to shotgun sequence ancient protein remains extracted from a 43 000 year old woolly mammoth ( Mammuthus primigenius ) bone preserved in the Siberian permafrost. For the first time, 126 unique protein accessions, mostly low-abundance extracellular matrix and plasma proteins, were con...

Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary period remain contentious. Here we use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, wooll...

The tip of a projectile point made of mastodon bone is embedded in a rib of a single disarticulated mastodon at the Manis site in the state of Washington. Radiocarbon dating and DNA analysis show that the rib is associated with the other remains and dates to 13,800 years ago. Thus, osseous projectile points, common to the Beringian Upper Paleolithi...