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Bone Surface Modifications, Reasonable Certainty, and Human Antiquity in the Americas: The Case of the Arroyo Del Vizcaíno Site


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Modifications on bone surfaces are taphonomic features that allow, among other aspects of environmental reconstruction, the assessment of human presence. The agents that cause such marks are diverse and of both biotic and abiotic origin. Among the former, marks made by human tools are of paramount importance for archaeologists and paleontologists to identify. Although it is possible to erroneously assign trampling marks to cut marks, several criteria have been recently developed so as to avoid such risks. These methods are applied here to the 30,000-year-old site of Arroyo del Vizcaíno (Uruguay), where over one thousand megafaunal remains have been collected. Some of them show marks that have been interpreted to be the result of the action of human tools. Using a database built up from previous studies of experimentally made marks as an actualistic model, it was concluded that the marks in the Arroyo del Vizcaíno site are unlikely to have been made by trampling, hence leaving human agency as the most feasible cause. This has important consequences for the debate on the human peopling of the Americas and on the process of extinction of the Pleistocene megafauna.
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The study of surface modifications on bones
is a valuable archaeological approach per-
mitting the identification of the agent that
created them. Among the most common modifi-
cations, root etching, carnivore scratching, rodent
gnawing, trampling and tool-made marks provide
information on the environment. Moreover, when
modifications of biotic agency are present, they
can be considered ichnofossils and can be used
to make inferences about the presence of a par-
ticular taxon. Such modifications are important
for archaeology, in particular when the species is
our own or a close relative.
Among many other examples, this approach
has been useful for some decades in cases such
as that of moas processed by metal tools in his-
torical times in New Zealand (Duff 1956), the
habits of hominids in Olduvai (Potts and Ship-
man 1981), and bone tool use in butchering a
proboscidean in Pleistocene North America
(Shipman et al. 1984). With the availability of
scanning electron microscopy (SEM), it has be-
come easier to distinguish cut marks made by
stone tools from gnaw marks made by nonhuman
predators or scavengers and from marks made
by an excavator’s or preparator’s tools (Potts
Richard A. Fariña
Modifications on bone surfaces are taphonomic features that allow, among other aspects of environmental reconstruction,
the assessment of human presence. The agents that cause such marks are diverse and of both biotic and abiotic origin.
Among the former, marks made by human tools are of paramount importance for archaeologists and paleontologists to
identify. Although it is possible to erroneously assign trampling marks to cut marks, several criteria have been recently
developed so as to avoid such risks. These methods are applied here to the 30,000-year-old site of Arroyo del Vizcaíno
(Uruguay), where over one thousand megafaunal remains have been collected. Some of them show marks that have been
interpreted to be the result of the action of human tools. Using a database built up from previous studies of experimentally
made marks as an actualistic model, it was concluded that the marks in the Arroyo del Vizcaíno site are unlikely to have
been made by trampling, hence leaving human agency as the most feasible cause. This has important consequences for the
debate on the human peopling of the Americas and on the process of extinction of the Pleistocene megafauna.
Las modificaciones en la superficie de los huesos son características tafonómicas que permiten, entre otros aspectos de la
reconstrucción del ambiente en que vivía el organismo, la evaluación de la presencia humana. Los agentes que causan esas
marcas son diversos y de origen tanto biótico como abiótico. Entre los primeros, es de la mayor importancia para disciplinas
como la arqueología y la paleontología la identificación de aquellas marcas hechas por herramientas humanas. Aunque es
posible asignar erróneamente marcas de pisoteo a marcas de corte, varios criterios se han desarrollado recientemente para
evitar tales riesgos. Esto se aplica aquí al yacimiento del Arroyo del Vizcaíno (Uruguay) de fecha 30.000 años aP, en el que
más de mil restos de megafauna ya han sido colectados. Algunos de ellos muestran marcas que fueron interpretadas como
productos de la acción humana. Usando una base de datos tomada de la bibliografía de marcas hechas experimentalmente
como un modelo actualista, se concluye que es muy improbable que esas marcas sean debidas al pisoteo, dejando así la acción
humana como la causa más probable. Esto plantea importantes consecuencias en el debate del poblamiento de América y en
el proceso de extinción de la megafauna pleistocena.
Richard A. Fariña Sección Paleontología, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
American Antiquity 80(1), 2015, pp. 193–200
Copyright © 2015 by the Society for American Archaeology
DOI: 10.7183/0002-7316.79.4.193
194 AMERICAN ANTIQUITY [Vol. 80, No. 1, 2015]
and Shipman 1981; Shipman 1981; Shipman and
Rose 1983).
However, when analyzing evidence for human
presence and interaction with animals, the most
important issue is avoiding the misidentification
of trampling marks (Behrensmeyer et al. 1986).
The phenomenon through which different agents
can yield similar results in open systems is called
equifinality, a concept borrowed from systems
theory (von Bertalanffy 1968) and applied to the
study of cut marks and taphonomy in general
(Lyman 2004). Quantitative approaches, such as
the pioneering work by Long and Walker (1977)
and Walker (1978), aided in minimizing this prob-
lem, although only in the last decade (e.g., Bello
and Soligo 2008; Bello et al. 2009; Domínguez-
Rodrigo et al. 2009) has major progress been
made in distinguishing between the surface mod-
ifications caused by the two main and potentially
most misidentifiable agents, i.e. trampling and
human tools.
Here I build a probabilistic model to be ap-
plied to those archaeological sites that show var-
iedly originated surface modifications on bones
as a way to set limits on equifinality in inter-
preting those modifications. In particular, this
report aims to provide a quantitative probability
of the correct identification of the trampling and
cut marks found in the 30,000 year-old site of
Arroyo del Vizcaíno, Uruguay (Fariña, Tam-
busso, Varela, Czerwonogora, et al. 2014). Given
the old age of this site, if cut marks can be iden-
tified with reasonable certainty, this study might
become a very important contribution to the de-
bate on human colonization of the Americas and,
given the proposed role of our species in that
process, the extinction of the megafauna (Fariña
et al. 2013).
Arroyo del Vizcaíno:
Main Characteristics of the Site
The megafaunal site of Arroyo del Vizcaíno, near
the town of Sauce, Canelones, Uruguay (Figure
1), is fully described in Fariña, Tambusso, Varela,
Czerwonogora, et al. (2014). First found in 1997
during a severe drought, the site is formed by a
streambed in a place where the Vizcaíno stream
becomes deeper, forming a natural pond on a
substrate of Cretaceous silicified sandstone. More
than 1,000 remains of at least 27 specimens of
South American Pleistocene megafauna have
been collected during the four field expeditions
undertaken to date (Fariña, Tambusso, Varela,
Czerwonogora, et al. 2014), mostly belonging to
the giant sloth Lestodon armatus but with about
6 percent of remains of other ground sloths,
glyptodonts, Toxodon platensis, a fossil horse, a
deer, a proboscidean, and the sabertoothed felid
Smilodon populator.
With the exception of a few redeposited ele-
ments in an upper bed, nearly all fossils of the
site were found in situ in a .60–.80 m thick bed
of greenish muddy sandy gravel (facies a) to
brownish muddy sand (facies b), the occurrence
of which may be due to slightly different sedi-
mentary conditions or perhaps differential post-
depositional oxidation events. No predominant
orientation of limb and elongated bones was
found. The taphonomy of the site suggests a bio-
genic origin, according to the representation of
bones with different hydraulic transportability
(Voorhies 1969). Although the existence of two
populations of bones cannot be determined to
date, it should not be ruled out that the bones
from the two facies of the fossiliferous bed could
have had different taphonomic histories. This is
particularly valid for those remains with surface
modifications that were carefully studied in Far-
iña, Tambusso, Varela, Czerwonogora, et al.
(2014), as explained below. The representation
of the anatomical units (percent minimal animal
units [MAU]) resembles those in kill sites asso-
ciated with gourmet consumption (Meltzer 2006).
Moreover, the mortality profile shows that 90
percent were adults, 2.6 percent were (mostly
subadult) juvenile individuals, and 7.4 percent
were old individuals. This profile is similar to
that seen at kill sites but different from those
found in attritionally, catastrophically, or acci-
dentally accumulated assemblages (Stiner 1990).
Nine radiocarbon assays were obtained at three
laboratories (URU, Laboratorio 14C, Comisión
Nacional de Arqueología, tedra de Radio-
química, Facultad de Química, Universidad de
la República, Uruguay; Beta Analytic Radiocar-
bon Dating, Miami, Florida, USA; and Oxford
Radiocarbon Accelerator Unit, University of Ox-
ford, UK). Samples were taken from both purified
and non-purified bone collagen, as well as from
wood. Although different procedures were un-
dertaken at different times and in different labo-
ratories, the ages reported are consistently close,
at about 30,000 radiocarbon years before present
(B.P.) (Fariña and Castilla 2005; Fariña, Tam-
busso, Varela, Czerwonogora, et al. 2014).
No carnivore tooth marks were identified.
Nearly 59 percent of the bones collected showed
modifications, with features identifiable as tram-
pling marks (Behrensmeyer et al. 1986). More
than one-third of the bones exhibited trampling
abrasion marks on over 25 percent of their surface
area. On the other hand, the suggested potential
human activity is supported by the surface mod-
ification present in about 40 bones (about five
percent of the identified specimens). A total of
15 of those marks were carefully studied in Far-
iña, Tambusso, Varela, Czerwonogora, et al.
(2014) with light microscopy under magnifica-
tions of 20x, 30x, and 45x. Pictures were taken
at different focal depths, a three-dimensional
model of each mark was built, and the cross-sec-
tional profiles were then digitized and measured.
Little lithic material has been collected to date,
due to the site having been only partially ex-
plored. Nonetheless, a small piece of translucid
silcrete was found that has macroscopical features
compatible with a scraper. Using a SEM at 700-
4300x, a rather dull and coarse area was observed
in that piece, with circular microdepressions that
are darker than the rest of the surface and that
extend along a large portion of one edge, which
is consistent with a second-stage micropolish, as
produced by working on dry hide.
Given the old age of the site, finding those
pieces of evidence was unexpected (but see Dille-
hay and Collins 1988; Guidon and Delibrias
1986). Unfortunately, the site has been only par-
Figure 1. Geographic location of the Arroyo del Vizcaíno site.
tially excavated and the landscape cannot be prop-
erly reconstructed with the current geological ev-
idence gathered. Therefore, at present it cannot
be determined whether this location is a kill or
butchering site.
In sum, there is a strong need for further dis-
cussion of the evidence found. In particular, it
seems crucial to make the best effort to correctly
assign the marks to the agent that created them,
as conducted in the recent study by Hockett and
Jenkins (2013) in Paisley Caves, Oregon.
Material and Methods
The database in Domínguez-Rodrigo et al.
(2009:Table 5) was used as the basis for the model
described below. The data consist of the absolute
values and percentages of 14 categorical variables
in their experimental sample of reproduced tram-
pling marks (n= 251), cut marks made with sim-
ple flakes (n= 246), and cut marks created with
retouched flakes (n= 105) in modern bones.
Three variables were chosen here according to
196 AMERICAN ANTIQUITY [Vol. 80, No. 1, 2015]
Figure 2. Microphotographs of bone surface modifications in remains from the Arroyo del Vizcaíno site: (a) cut mark on
the rib CAV 451, showing its straight trajectory; (b) 3D reconstruction of the same mark; (c) same reconstruction, with
a horizontal plane representing the bone surface before its modification (and note that the shoulders are observed to pro-
trude above that plane); (d) V-shaped cross section of the same mark; (e) trampling mark on the surface of the femur
CAV 722, showing its wide, U-shaped cross section (and its curvilinear trajectory is not apparent because only a short
part is shown); (f) 3D reconstruction of the same mark, in which no shoulder effect can be observed.
their likelihood (and easiness) of observation in
fossil bones (Figure 2): groove trajectory (straight,
curvy, or sinuous), groove section shape (V-
shaped or otherwise), and shoulder effect (present
or absent). It should be noted that this categorical
classification is not entirely devoid of some de-
gree of subjectivity, a topic that merits its own
discussion elsewhere. Other variables, such as
length, presence of a barb, and microstriae, are
more difficult to find preserved in prehistoric ma-
terial (Behrensmeyer et al. 1986; Domínguez-
Rodrigo et al. 2009). The variables selected were
among those with the highest loadings in two
first dimensions, i.e., those that allowed for better
differentiation of cut from trampling marks in
the multidimensional analysis (categorical prin-
cipal components analysis) used by Domínguez-
Rodrigo et al. (2009). The results are provided as
a probability of reclassification between 0 and 1.
Higher values indicate a greater probability of a
consistent reclassification.
Bello and Soligo (2008) used another approach
based on quantitative variables measured on ex-
perimentally inflicted marks on modern bones:
the angles between the slopes of the cut mark and
the unaffected bone surface, the angle between
both slopes, the angle of the bisector of the open-
ing angle of the cut mark relative to the unaffected
bone surface, the height of the shoulders formed
on either side of the cut, the radius of a circle
fitted to the floor of the cut-mark profile, and the
radius of a circle fitted to the floor of the cut-
mark profile. Although they focused their ap-
proach on the microscopic features that allow for
identifying cut marks made by flint tools and
metal knives at different hand positions, here I
combined their data with those in Fariña, Tam-
busso, Varela, Czerwonogora, et al. (2014) to in-
clude surface modifications made by trampling.
Here I present results based on all 15 marks
in Fariña, Tambusso, Varela, Czerwonogora, et
al. (2014) identified as the possible product of
human tools. They are found in the following
material, selected among those that had macro-
scopically promising marks and little to no tram-
pling, at least in the same area: tibia (CAV 395—
not CAV 385, as erroneously written in Fariña,
Tambusso, Varela, Czerwonogora, et al. (2014)—
1 mark studied), rib (CAV 451, 3 marks studied),
rib (CAV 452, 3 marks studied), long bone frag-
ment (CAV 453, 2 marks studied), rib (CAV 458,
1 mark studied), radius of a Glyptodon sp. (CAV
459, 1 mark studied), rib (CAV 475, 1 mark stud-
ied), hyoid (CAV 476, 1 mark studied), ulna (CAV
520, 1 mark studied), mandible (CAV 897, 1 mark
studied). Unless otherwise stated, all remains
were assigned to the giant sloth Lestodon arma-
tus. All these specimens showed excellent preser-
vation and were classified as Behrensmeyer’s
(1978) weathering stage 1, with smooth surfaces
and no evidence of cracks, such as those made
by alternating episodes of drying and wetting.
Among the 251 trampling marks in the database
provided by Domínguez-Rodrigo et al.
(2009:Table 5), 75 (29.8 percent) are straight,
while this feature is observed in 94.6 percent (332
out of 351) of the retouched and unretouched cut
marks (Table 1). Therefore, the probability of re-
classifying a cut mark showing a straight trajec-
tory is .76, which results from the normalized ra-
tio of straight cut marks to all straight marks:
94.6/(29.8+94.6). Accordingly, if that straight
mark is due to trampling, it will be correctly re-
classified with a probability of .24.
Only 10 (or 4 percent) trampling marks show
a V-shaped section. Among cut marks, 280 show
this characteristic, increasing the appropriate per-
centage to 79.8, making the probability of cor-
rectly reclassifying a cut mark with a V-shaped
section .952. Therefore, this probability is only
.048 for a V-shaped trampling mark.
Finally, the shoulder effect is present in 15
(5.9 percent) trampling marks and in 159 (45.3
percent) cut marks. Thus, the correct reclassifi-
cation of a shouldered cut mark has a probability
of .885. In turn, a shouldered trampling mark has
a .115 probability of being correctly reclassified.
Using those figures as an actualistic model to clas-
sify marks of unknown origin and assuming that
the three chosen variables are independent of each
other, it follows that a mark that is straight, V-
shaped, and with shoulders has a probability of
1.3 x 10-3 to have been made by trampling.
In Figure 3, two variables considered by Bello
and Soligo (2008), depth in ?m and opening angle
in degrees, are shown for some marks. The ex-
perimental marks (open symbols) are from data
in Bello and Soligo (2008) representing marks
inflicted by a handaxe or by a flint flake at dif-
ferent angles. Those represented by solid symbols
are observed in bones from the Arroyo del Viz-
caíno site (Fariña, Tambusso, Varela, Czerwono-
gora, et al. 2014).
In Fariña, Tambusso, Varela, Czerwonogora, et
al. (2014), 15 marks with all of the three features
discussed above were studied on bones belonging
to megafaunal species in the Arroyo del Vizcaíno
site. Those elements belong mostly to the giant
ground sloth Lestodon armatus, but also to a
glyptodont, and were assigned to human agency.
According to the model presented here, the prob-
ability that none of them were correctly identified
as human made and, instead, that all of them were
made by trampling is only 6 x 10-44. Given the
unlikelihood of equifinality, the conclusion
reached in Fariña, Tambusso, Varela, Czerwono-
gora, et al. (2014) and further discussed in Fariña,
Tambusso, Varela, Di Giacomo, et al. (2014) as-
signing human agency to these marks can be con-
sidered sound, thus yielding reasonable certainty
about their proposal.
The opening angle yields an unambiguous cri-
terion for distinguishing marks made by cutting
from those made by trampling, as shown in Figure
2. Depth, alternatively, had been considered in-
formative by some authors (e.g., Olsen and Ship-
man 1988), but the trampling marks studied in
Fariña, Tambusso, Varela, Czerwonogora, et al.
(2014) are about as deep as those in Bello and
Soligo (2008). However, the cut mark on a
Lestodon bone from the Arroyo del Vizcaíno site
plotted in Figure 2 is much deeper than trampling
marks observed here. A third readily observable
variable, the height of the shoulder, was not de-
picted here because it was not present in the two
trampling marks studied.
It should be noted that, apart from the variables
chosen, which have been thoroughly demon-
strated to be useful for the analysis in this paper,
most, if not all, of the marks studied show addi-
tional features that have been considered relevant
in the literature (Bello and Soligo 2008;
Domínguez-Rodrigo et al. 2009), such as internal
microstriations, Hertzian cones, asymmetry, and
small floor radius. Moreover, sharp points, a fea-
ture considered relevant by Hockett and Jenkins
(2013), were observed in several of the 15 marks
referred to here, while most of them have roughly
the same size. Finally, a few other bones (but
none of those listed above) show multiple inci-
sions, forming a “Y” or “braided” shape near one
end of the cut.
Although quite a few sites are considered to
have broken the Clovis Barrier (Hockett and Jenk-
ins 2013), the results presented here stress the
unexpected nature of the Arroyo del Vizcaíno
site. The evidence found in this locality suggest-
ing human presence in South America at 30,000
B.P. is not well explained by the current view of
the peopling of the Americas, rightly summarized
by Pitblado (2011) as a model of two migrations
based on both archaeological and genetic evi-
198 AMERICAN ANTIQUITY [Vol. 80, No. 1, 2015]
Table 1. Number of Cases in the Database from Domínguez-Rodrigo et al. (2009).
Straight trampling marks 75 V-shaped trampling marks 10 Shouldered trampling marks 15
Total trampling marks 251 Total trampling marks 251 Total trampling marks 251
Percentage 29.8 Percentage 4 Percentage 5.9
Straight unretouched cut marks 230 V-shaped unretouched cut marks 238 Shouldered unretouched cut marks 81
Total unretouched cut marks 246 Total unretouched cut marks 246 Total unretouched cut marks 246
Percentage 93.5 Percentage 96.7 Percentage 32.9
Straight retouched cut marks 102 V-shaped retouched cut marks 42 Shouldered retouched cut marks 78
Total retouched cut marks 105 Total retouched cut marks 105 Total retouched cut marks 105
Percentage 97.1 Percentage 40 Percentage 74.3
Straight cut marks 332 V-shaped cut marks 280 Shouldered cut marks 159
Total cut marks 351 Total cut marks 351 Total cut marks 351
Percentage 94.6 Percentage 79.8 Percentage 45.3
Probability reclassification of .240 Probability reclassification of .048 Probability reclassification of .115
trampling marks trampling marks trampling marks
Probability reclassification of .760 Probability reclassification of .952 Probability reclassification .885
cut marks cut marks cut marks
dence. The first pulse must have occurred around
16,000 or 15,000 years B.P. by watercraft along
the coast of Beringia and western North and South
America, while the second must have taken place
1,000 years later, with proto-Clovis hunters trav-
elling through the ice-free corridor.
Instead, the Arroyo del Vizcaíno site should
be included among the unanticipated findings,
vividly described by Pitblado (2011:360) as be-
longing to the “only sure bet: that at least a few
pending peopling finds will be of the ’wow— I
never saw that coming’ variety.” As such, Arroyo
del Vizcaíno should be added to the pre-Last
Glacial Maximum (and controversial) sites in the
Americas with evidence of human presence,
which include Toca do Boqueirão da Pedra Fu-
rada (Guidon and Delibrias 1986) in Brazil and
Monte Verde I (Dillehay and Collins 1988) in
Chile. It can be claimed that until datable human
remains are found, the association between the
evidence and the age found by Fariña, Tambusso,
Varela, Czerwonogora, et al. (2014) is the closest
possible, as in some cases it is the same object
(the marked bone) that has been dated and shows
evidence of human-made marks. Because in some
cases the very same object (the marked bone)
that has been dated shows the evidence of human
presence, it can be claimed that the association
between that evidence and the age in the Arroyo
del Vizcaíno site is the closest possible, at least
until datable human remains are found. Moreover,
the approach used here must be developed with
more complete databases and more refined mod-
els, in order to enhance and further reduce the
risks posed by equifinality in the study of marks
on bones.
Acknowledgments. This is a contribution to the project “
Prospección de nuevos sitios fosilíferos y arqueológicos en
el área del Arroyo del Vizcaíno,” funded by CSIC, Universidad
de la República. Roberto Bracco was an important influence
in developing the ideas conveyed here. Ángeles Beri, Patricia
Grigny, Christine Lucas, and Luciano Varela read previous
versions of this manuscript. I received substantial help with
Figures 1 (Eva Fariña) and 2 (Luciano Varela and Sebastián
Tambusso). Three anonymous reviewers made many useful
Data Availability Statement. Data are published in Bello and
Soligo (2008), Domínguez-Rodrigo et al. (2009), and Fariña,
Tambusso, Varela, Czerwonogora, et al. (2014).
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Accepted September 1, 2014.
200 AMERICAN ANTIQUITY [Vol. 80, No. 1, 2015]
... Here we address another potential archaeological site purporting site evidence to support a pre-LGM occupation for the Americas: Arroyo del Vizcaíno (AdV), Uruguay. At AdV, researchers have argued for human occupation between 30,000 and 27,000 cal yr BP (Arribas et al. 2001;Domínguez-Rodrigo et al. 2021;Fariña 2015;Fariña et al. 2014aFariña et al. , 2014bFariña and Castilla 2007). ...
... Thus, Fariña et al. (2014a, 5) concluded that these data support the interpretation that the bonebed "accumulated as the result of biogenic (particularly human) agency." This claim was reiterated by Fariña (2015) after further evaluating the 15 cutmarks by comparing them to a database of cutmarks constructed from zooarchaeological experiments. ...
... They argue that eight of the cutmarks originally interpreted to be anthropogenic are supported by their DL approach and conclude that AdV supports that this site's modified bones could potentially constitute one [of] the oldest direct evidence of humans in South America and, therefore, add more sound data to the position of a pre-LGM human presence in the Americas as a whole. (Domínguez-Rodrigo et al. 2021, 4) After two decades of study, the primary evidence offered for early human occupation at the AdV site includes 105 purported stone tools and 65 purported cutmarks on four bones out of 1145 faunal specimens, though only 13 cutmarks have been systematically studied, with eight of those being supported by independent evaluation (Arribas et al. 2001;Domínguez-Rodrigo et al. 2021;Fariña 2015;Fariña et al. 2014a;Fariña and Castilla 2007). As we detail below, questions remain about the validity of these claims, and we hope future work will seek to clarify several issues associated with the AdV assemblage. ...
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Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior to the Last Glacial Maximum (33,000–31,000 cal BP) based on the presence of purported stone tools and cutmarks on bones. We provide a summary of their research and critically evaluate these claims. We conclude that the claims of a pre-LGM occupation at AdV are unsupported due to: (1) equivocal evidence that the purported stone tools are culturally modified; (2) insufficiently documented spatial and contextual information; (3) inadequate geological research leading to an unconvincing site formation model; and (4) inadequate testing of alternative hypotheses for bones with surface modifications. We conclude that the site is best interpreted as a natural time-transgressive accumulation of mammal bones and other organic and inorganic materials within a fluvial setting spanning four millennia, and that bone surface modifications are the product of natural site formation processes rather than human agency.
... In Fariña et al. (2014a), 15 of these BSM (on 11 bones mainly of Lestodon but also of a glyptodont) were studied by taking 40x photographs at several depths and building up 3D models of the marks. The results showed compelling microscopic evidence of human agency, as will be discussed below (also see Fariña 2015 andDomínguez-Rodrigo et al. 2021). Most importantly, the dates obtained were unexpectedly old, between 27,000 and 30,000 14C yr BP (about 31,000-34,000 cal yr BP), which doubled the traditionally accepted age for the oldest human presence in the Americas (see, for example, Pitblado 2011 for further discussion). ...
... A number of other studies suggest cut-marks can occur through natural processes (see, for example, Haynes and Stanford 1984;and Lupo and O'Connell 2002). This subject was thoroughly discussed with regard to the AdV site in Fariña (2015), which is summarized below. Furthermore, a recent study by Dominguez-Rodrigo et al. (2021) addressed this issue using advanced deep learning algorithms in order to evaluate bone surface modifications (BSM) in bones from AdV. ...
... Questioning the main evidence for human actions in that way, could be a severe weakness in our argument. Therefore, we (Fariña 2015: Domínguez-Rodrigo et al. 2021) undertook probabilistic and AI approaches that might shed light on this issue ...
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Here, we will address further criticisms in terms of the weakness and the strength of our proposal that the AdV is more than a particularly rich paleontological site, and our consequent intent to take it from a possible archaeological site to a probable one. In doing this, we are attempting to make progress in the central debate about the AdV and the more general subject of the peopling of the Americas. This matter is of major academic importance but also has ethical implications due to the proposed role of humans in the demise of the Pleistocene megafauna (see Sandom et al. 2014 for a thorough discussion).
... The scenario mostly accepted by both archaeological and genomic studies is the one that proposes a settlement of the American continent with an intermediate chronology between~18,500 to 13,000 calibrated years before present (cal BP) and a human entry in South America shortly after [3][4][5][6][7][8]. Moreover, other controversial hypotheses suggest a longer chronology with a South American settlement before 18,000 cal BP [9][10][11][12][13][14][15]. ...
... The dating for this sublineage is 18.7 kya (16.5-21.2), which is older than that of 12.5 kya (11)(12)(13)(14) reported in literature [6]. We found a new sub-lineage, not described in ISOGG, supported by 2 SNPs named Q-GMP73 and Q-GMP74 (see S6 Fig, S2 and S4 Tables) with a dating of 18.2 kya (16.1-20.6). ...
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The settlement of the Americas has been the focus of incessant debate for more than 100 years, and open questions regarding the timing and spatial patterns of colonization still remain today. Phylogenetic studies with complete human Y chromosome sequences are used as a highly informative tool to investigate the history of human populations in a given time frame. To study the phylogenetic relationships of Native American lineages and infer the settlement history of the Americas, we analyzed Y chromosome Q Haplogroup, which is a Pan-American haplogroup and represents practically all Native American lineages in Mesoamerica and South America. We built a phylogenetic tree for Q Haplogroup based on 102 whole Y chromosome sequences, of which 13 new Argentine sequences were provided by our group. Moreover, 1,072 new single nucleotide polymorphisms (SNPs) that contribute to its resolution and diversity were identified. Q-M848 is known to be the most frequent autochthonous sub-haplogroup of the Americas. The present is the first genomic study of Q Haplogroup in which current knowledge on Q-M848 sub-lineages is contrasted with the historical, archaeological and linguistic data available. The divergence times, spatial structure and the SNPs found here as novel for Q-Z780, a less frequent sub-haplogroup autochthonous of the Americas, provide genetic support for a South American settlement before 18,000 years ago. We analyzed how environmental events that occurred during the Younger Dryas period may have affected Native American lineages, and found that this event may have caused a substantial loss of lineages. This could explain the current low frequency of Q-Z780 (also perhaps of Q-F4674, a third possible sub-haplogroup autochthonous of the Americas). These environmental events could have acted as a driving force for expansion and diversification of the Q-M848 sub-lineages, which show a spatial structure that developed during the Younger Dryas period.
... En Uruguay, le site à ciel ouvert d'Arroyo del Vizcaíno (Canelones, sud de l'Uruguay) a fourni un niveau archéologique (Fariña et al., 2014). Le site a livré 1 145 ossements de mégafaune pléistocène, dont 5 % présentent des traces de découpe, et 10 artefacts en quartzite datés entre 27000 ± 450 14 C BP et 30100 ± 600 14 C BP (Fariña et al., 2014, 3-4, S1, fig. 2 ; Fariña, 2015). Localisé dans la vallée de la rivière Luján en Argentine, Zajón Zabaleta est un site secondaire d'origine fluvilatile dont la composante inférieure ZZ I appartient au MIS 3 et la composante supérieure ZZ II, au MIS 2. Un éclat anthropique de calcedoine exogène a été trouvé dans l'unité 3a qui est la couche basale de la séquence de dépôt Luján Rouge, associé à des losanges de percussion et des fragments d'os avec des marques de découpe. ...
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En 1995, D. Lavallée publie Promesse d’Amérique. La Préhistoire de l’Amérique du Sud, une monographie de référence encore à ce jour sous bien des aspects. Plus de vingt-cinq ans après, aucune autre publication de langue française n’a tenté de reproduire de projet aussi ambitieux portant sur l’ensemble de la Préhistoire de l’Amérique du Sud. Loin de cette ambition, ce travail présente cependant une nouvelle vision globale des premiers peuplements humains de ce sous-continent, à la lumière des nouvelles données archéologiques, paléoenvironnementales et génétiques qui enrichissent notre compréhension des phénomènes techniques et culturels produits entre le Pléistocène récent et le début de l’Holocène. Cette perspective globale actualisée permet d’observer une Préhistoire sud-américaine plus longue qui commence au moins 50000 BP bien avant le Dernier Maximum glaciaire (DMG ; ~26500-19000 cal. BP). Débitages d’éclats unipolaires, bipolaires sur enclume et façonnage unifacial y précèdent l’émergence des façonnages bifaciaux associés à la fabrication de pointes de projectiles ; un phénomène clairement postglaciaire. La période postérieure au Bølling–Allerød/Antarctic Cold Reversal marque la transition Pléistocène-Holocène au cours de laquelle une importante diversité de phénomènes techniques émerge dans presque toutes les régions d’Amérique du Sud avec une vitesse inconnue des histoires évolutives d’autres parties du monde.
... 31,000 cal BP. Some of the bones clearly bore cut marks (Fariña 2015;Toledo 2017: 26-27, figs. OW18 and OW19). ...
This paper includes the study of use-traces on lithic technologies manufactured by different hunter-gatherer societies from the Central Plateau of Santa Cruz (Argentina). The time period considered is from the Pleistocene–Holocene transition to the Late Holocene (ca. 12,000 years C14 BP to historical times). Techno-morphological and micro-wear analysis as experimental archaeology were applied to the lithic materials of the Piedra Museo locality (AEP-1 site). Similarities in the design and use of lithics during the different periods of occupation were identified. The results obtained are comparatively analysed with peopling models proposed for the study area and other lithic assemblages from nearby sites. The application of micro-wear analysis to these materials has provided a greater support to the hypotheses about the AEP-1 functionality; as well as to determine the economic practices developed by the groups that inhabited the Central Plateau of Santa Cruz (Patagonia, Argentina).KeywordsHunter-gatherersLithic technologyMicro-wear analysisCentral plateau of Santa Cruz provinceArgentina
... As it stands, the presence of real tools among this assemblage has not been demonstrated.  Arroyo Vizcaíno (Uruguay), dating to c. 34,000 cal BP, is a faunal assemblage with possible cut-marks and with one single flake that may have been used to process the bones (Fariña 2015). However, zooarchaeologists have raised questions about the anthropic nature of the marks (Suárez et al. 2014;Borrero 2016). ...
Many archaeologists are still skeptical about a human presence in the Americas during or before the Late Glacial Maximum (LGM), considering that the claim is not yet sustained by hard evidence. Boqueirão da Pedra Furada (Brazil) is one of the most famous pre-LGM claims, but the site has so far been considered ambiguous, and similar concerns have been raised about nearby sites. Nonetheless, for E. Boëda and co-workers, who have been working at these sites, researchers who are still skeptical about the anthropic origin of the assemblages have a psychological barrier and no scientific arguments. Are all skeptics completely blinded by their preconceptions that they cannot see the obvious and unambiguous evidence? To find out, I reviewed the numerous publications of the Piauí sites, and the outcome of my analysis is quite simple: the anthropic nature of the LGM/pre-LGM artifacts of the Piauí sites has not been demonstrated.
... En l'état, nous considérons que la présence de véritables outils n'est pas démontrée.  Arroyo Vizcaíno (Uruguay), ca 34 000 cal. BP, est un assemblage faunique avec de possibles traces de découpes et un seul éclat qui aurait été utilisé (Fariña, 2015). Comme pour Bluefish Caves, certains archéozoologues remettent en question le caractère anthropique des marques (Suárez et al., 2014 ;Borrero, 2016). ...
... Contrary to Domínguez-Rodrigo et al.'s (2009a) observations, the presence of a barb was argued by Shipman and Rose (1983a), and supported by Fisher (1995), to be one of few features unique to stone tool cut marks, alongside shoulder effects and splitting (Eickhoff and Herrmann 1985). It has been argued that, due to the general shallowness of barbs as incidental striations, they are unlikely to be preserved in the archaeological record Domínguez-Rodrigo et al. 2009a;Fariña 2015). With this line of thought, there is a base assumption that all hominin butchers sought to preserve the cutting edge and maintain tool uniformity, thereby leaving only incidental cut marks described as epiphenomena (Lyman 1995(Lyman , 2005. ...
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Modifications to the surfaces of fossil bones are one of the most important lines of evidence for understanding different issues in palaeoanthropological, archaeological, and taphonomic research. Bone surface modifications (BSM) are used to infer past lifeways and behaviours through site formation processes, subsistence patterns and adaptations and how they influenced human evolution, as well as patterns of economic and social evolutions. The study of BSM first appeared in palaeontology in the mid-19th Century, before gaining traction in archaeology during the processual boom of the 1960s. By identifying BSM from ethnographic studies of BSM created by people in the present day and comparing them to marks found in the archaeological record, archaeologists were able to tie traces to specific bone modifying actions (e.g. Binford 1978; Brain 1981; White 1954). However, traces left by non-human modifiers can mimic those produced by humans (e.g. Blumenschine et al. 1996; Olsen and Shipman 1988; Selvaggio 1994a; Shipman and Rose 1984). Experimental taphonomic studies in zooarchaeology have been largely conducted with the goal of confidently tying traces to known actors and effectors (Gifford-Gonzalez 1989b, 1991). However, variation in experimental design, experimental bone subjects, and how the resultant BSM are classified and analysed has contributed to a lack of consensus between researchers. For example, cut marked bones found in deposits dating to 3.39 million-years-ago (Ma) challenged the current paradigm that butchery, meat-eating behaviours and, subsequently, stone tool use were present in pre-Homo hominins (Domínguez-Rodrigo et al. 2011; McPherron et al. 2011). Furthermore, debates based on bone surface modification interpretations illustrate the lack of consensus amongst researchers about how to best identify and differentiate anthropogenic from non-anthropogenic modifications on bones. In the context of the origins of tool-assisted butchery, having a robust method to identify these traces is a foremost concern for understanding our own evolution. Resolving this issue requires two things: 1) a large dataset in which marks on bones have been produced experimentally under highly controlled conditions; and 2) a replicable method for quantitatively analysing and describing traces on bone surfaces. This research provides impetus for the standardisation of bone surface modification studies, specifically the experimental and analytical methods, as well as how researchers identify and classify modifications and, subsequently, communicate their results and interpretations.
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, it must be mentioned that they decide to utterly ignore a few lines of evidence that sustain the questioned hypothesis (mortality profile of the individuals of the megafauna found there, representation of their anatomical regions, relative proportions of the Voorhies groups, etc.), state misled interpretation of the chronology and stratigraphy, refuse to accept the presence of human-modified lithics and show also non-acceptance of the conclusions of our thorough study of the key evidence, the cut-marks (Fariña et al. 2014, Fariña 2015, Domínguez-Rodrigo et al. 2021), based on a purported ideal of how a site should be researched, which leave aside those that point out at different conclusions from theirs.
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Far distant from the presumed entry point of the Bering Straits, archaeological sites discovered in southern Patagonia, at the very southern extremity of the Americas, have always played a significant role in the development of models of the initial settlement of the American continents. An early postglacial dating of the site of Fell’s Cave just north of the Straits of Magellan was an important component of the now-disproven “Clovis-first” model, which proposed that both continents were very rapidly populated by highly mobile specialized hunters of megafauna upon entry through an ice-free corridor just after the end of the Last Glacial Maximum. The model offered here, supported by ethnographic records of hunter/gatherer behaviour and new South American archaeological sites with chronometric dates before the Last Glacial Maximum, proposes that the settlement of the Americas was actually a very lengthy process of hunter/gatherer cultural adaptations to highly diverse environments. With the amelioration of climate in the early postglacial period, population growth increased the archaeological visibility of these populations, with a marked growth in the number of known archaeological sites. It was at this time in the early postglacial period that human groups expanded into southern Patagonia, the southernmost area of the globe to come into the human world.KeywordsSouth AmericaLast glacial maximumPostglacial timesPeopling modelsRoutes
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In Farina et al . [[1][1]], we claimed that a rich fossiliferous locality, Arroyo del Vizcaino (hereafter, AdV), with marked bones that are much older than widely accepted for human presence in the Americas, deserved ‘to be included in the agenda of early American peopling, either as a not
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Megafaunal extinction in the late Pleistocene is a topic of great academic interest that also arouses ethical issues, due to the proposed impact of humans as its possible cause. Evidences on human-megafauna interaction are scarce, especially in South America, where this issue is entangled with the debate on the date of human arrival. Here we present the results of two radiocarbon datings of material found in a site in the Arroyo Vizcaíno, Uruguay. One of them was a rib and the other a clavicle, both belonging to an extinct giant mammal, the Pleistocene ground sloth Lestodon. The clavicle shows human-made marks. The analyses yielded consistent results, between 28 and 29 kybp, a much older age than predicted by the present paradigm of peopling of the Americas and from currently accepted datings, which cluster at about 12 kybp.
Bones of recent mammals in the Amboseli Basin, southern Kenya, exhibit distinctive weathering characteristics that can be related to the time since death and to the local conditions of temperature, humidity and soil chemistry. A categorization of weathering characteristics into six stages, recognizable on descriptive criteria, provides a basis for investigation of weathering rates and processes. The time necessary to achieve each successive weathering stage has been calibrated using known-age carcasses. Most bones decompose beyond recognition in 10 to 15 yr. Bones of animals under 100 kg and juveniles appear to weather more rapidly than bones of large animals or adults. Small-scale rather than widespread environmental factors seem to have greatest influence on weathering characteristics and rates. Bone weathering is potentially valuable as evidence for the period of time represented in recent or fossil bone assemblages, including those on archeological sites, and may also be an important tool in censusing populations of animals in modern ecosystems.
In the late 1920s outside a sleepy remote New Mexico village, prehistory was made. Spear points, found embedded between the ribs of an extinct Ice Age bison at the site of Folsom, finally resolved decades of bitter scientific controversy over whether the first Americans had arrived in the New World in Ice Age times. Although Folsom is justly famous in the history of archaeology for resolving that dispute, for decades little was known of the site except that it was very old. This book for the first time tells the full story of Folsom. David J. Meltzer deftly combines the results of extensive new excavations and laboratory analyses from the late 1990s, with the results of a complete examination and analysis of all the original artifacts and bison remains recovered in the 1920s - now scattered in museums and small towns across the country. Using the latest in archaeological method and technique, and bringing in data from geology and paleoecology, this interdisciplinary study provides a comprehensive look at the adaptations and environments of the late Ice Age Paleoindian hunters who killed a large herd of bison at this spot, as well as a measure of Folsom's pivotal role in American archaeology.
Experiments were performed to determine the effectiveness of obsidian tools with different forms of edge treatment for animal processing. For most butchering tasks, primary flakes with unmodified working edges were more effective than bifacially pressure-flaked tools. The data presented indicate considerable variability among animal species in the demands placed on tools used for specific butchering tasks. It is suggested that consideration by prehistoric hunters of factors such as tool longevity and raw material availability could have resulted in the use of butchering tools with less than optimal cutting characteristics.