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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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200 AMERICAN ANTIQUITY [Vol. 80, No. 1, 2015]
... This early occupation of the continent can be even older, as suggested by a Bayesian age modelling of the oldest archaeological record and genetic evidence [14,15]. Adding to this, compelling evidence of a pre-LGM human presence in America could potentially be found at Arroyo del Vizcaíno [16][17][18][19] (hereafter, AdV) in southern Uruguay (34°37'2.92 00 S, 56°2'32.54 ...
... A total of 12 radiocarbon dates, which cluster at around 30 14 C kyr BP [16,17] (over 33 cal kyr BP), have been obtained from purified and non-purified collagen as well as from wood in different laboratories and at different times. The potential existence of cut-marks on the AdV bones advocates an earlier human presence in America, just before the LGM [18]. Indeed, the dates obtained and the possible human modifications are from the very same objects (i.e. the same marked bones), thus suggesting a very strong association of the agency and the dates [16,17]. ...
... This high accuracy of CNN in discriminating cut-marks from trampling marks (and other BSM), when using small [27] and large [28] training datasets, constitutes the best objective tool available for identifying cut-marks in the archaeological record. Given that some of the claims for the earliest presence of humans in the Americas are based partially or mostly on the interpretation of BSM on bones [5,11,18], here we will apply this DL method to the ichnological evidence from the approximately 30 kyr BP AdV site, where a sample of the bone assemblage exhibits both trampling marks and purported cut-marks. Here, we will test this assumption and, by extension, the evidence of human manipulation of bones at the site. ...
The earliest widely accepted presence of humans in America dates to approximately 17.5 cal kyr BP, at the end of the Last Glacial Maximum (LGM). Among other evidence, this presence is attested by stone tools and associated cut-marks and other bone surface modifications (BSM), interpreted as the result of the consumption of animals by humans. Claims of an older human presence in the continent have been made based on the proposed anthropogenic modification of faunal remains; however, these have been controversial due to the highly subjective nature of the interpretations. Here, we employ advanced deep learning algorithms to objectively increase the accuracy of BSM identification on bones. With several models that exhibit BSM classification accuracies greater than 94%, we use ensemble learning techniques to robustly classify a selected sample of BSM from the approximately 30 kyr BP site of Arroyo del Vizcaíno, Uruguay. Our results confidently show the presence of cut-marks imparted by stone tools on bones at the site. This result supports an earlier presence of humans in the American continent, expanding additional genetic and archaeological evidence of a human LGM and pre-LGM presence in the continent.
... 31,000 cal BP. Some of the bones clearly bore cut marks (Fariña 2015;Toledo 2017: 26-27, figs. OW18 and OW19). ...
This book is the result of three decades of work at Piedra Museo locality and mainly in Alero Piedra Museo 1 (AEP-1), a site that is central to relevant issues concerning Patagonian and American archaeology in general. This site has a very long occupational history, one of the longest recorded for Patagonia east of the Andes. My memories about the site are related to the visit during the international INQUA workshop held in 2000 and hosted by Laura Miotti at the National University of La Plata. I have seen research progress throughout a great part of my career, as many of the authors of these papers have been my lifelong colleagues, and friends and some even have been my students. That is to say, in no way can I claim to be an unbiased reader. My first comment is related to a characteristic of this book, apparently disconnected from its academic strength: the language chosen by the editors. In her introduction, Miotti mentions other books written in English that deal with important early Patagonian sites: one by Bird (1988), edited by Hyslop, and another one by Dillehay (1997). She also mentions two books in Spanish written by Gradin and Aguerre (1994) and by Massone (2004). That is, the local authors tend to present a great amount of detailed information in Spanish, their native language. The same is true if we look further north into the Pampean region, where even if Mazzanti and especially Politis publish regularly in English, the books containing detailed basic information about the early sites they study are in Spanish (Politis et al. 2014, Mazzanti and Quintana 2001). This is a different case; although part of the information contained here has already been published in both English and Spanish, this book constitutes a special effort to make first-hand data, which as mentioned above is relevant for both North and South American archaeology, available to English readers. We have already dwelled on this subject in our Introduction to the Southbound volume (Miotti et al. 2012) and it also was the spirit that guided a previous volume (Miotti et al. 2003). It is my desire that this effort is appreciated as such and the information here presented is widely used and cited. I have a clear image of Luis Borrero at the 2013 Santa Fe Paleoamerican Odyssey meeting urging North American archaeologists working on peopling issues to read original papers in Spanish. I cannot agree more on this issue. This is one of the v vi Foreword rare occasions where English readers can access data and also concerns and practical information about an early site in remote Patagonia in their mother tongue. Goebel, in this book, goes one step forward and advocates for joint working in interdisciplinary international projects that function on a two-way basis. The following paragraphs highlight some of what I believe are the book´s strengths. The introduction presents a vivid description of what the archaeological fieldwork is like in Argentina. Through the site’s research history, Miotti paints a picture of the context in which many of our research projects are carried out. It is relevant to understand under what conditions knowledge is constructed in our country. De Aparicio, a geologist, first recognized the archaeological significance of the locality during the early twentieth century. The prominent space dedicated to paleoenvironmental studies in this book follows in this tradition of shared interdisciplinary work which is commonly undertaken by many of the authors, most of whom studied or work at the Natural Sciences Faculty and Museum at La Plata University. The book can be consulted to obtain information on different issues presented at several spatial and temporal scales. Two chapters are the skeleton on which the others rest: they deal with geoarchaeology and chronology. The former is concerned with both the general geology and the site and local stratigraphy; considerations on soil-forming processes and surface stability are basic to the interpretation of archaeological contexts. The latter presents a careful explanation of the location and characteristics of the charcoal samples which are particularly relevant as the earliest occupational event in the Lower Component (at SU 6) is dated between 13,100 and 12,000 cal yr BP. Site chronology as addressed by other authors is also discussed in detail. As readers, we are left with an intriguing question: what is the dating of the Mylodontidae rib with cutmarks from the lower occupational level? The paleoenvironment and paleoecology chapters in Part I include several proxies. There is information about the glacial environment setting a general geographical picture for the human occupation, about the coexistence of people and fauna from the Late Pleistocene to the Middle Holocene in Fuego-Patagonia, about the climatic and vegetation regional history as seen through pollen analysis, and on diatom analysis from the paleolake sediments close to Piedra Museo. Additionally in Part II, there is a specific chapter on δ13C and δ15N analysis on extinct fauna and guanaco remains. Most of these chapters present analysis at the site or locality scale, but correlate results with paleoenvironmental data from Patagonia, thus the volume acquires regional significance on these issues. Another interesting approach in this section is that, although many researchers from other disciplines author these chapters, they reveal a close understanding of the site´s archaeology. As an archaeologist, I am thankful; it makes their studies relevant to my interests and those of other colleagues, which is not always the case. The second part of the book is dedicated to papers dealing with the material record at Piedra Museo. These chapters show a cohesive comprehension of the paleoenvironmental and stratigraphic interpretation at the site and discuss activities carried out during different moments of site occupation. Thus, information from faunal analysis reinforces interpretations from lithic analysis and vice versa. There are three chapters dedicated to faunistic studies, three to lithic analysis at site AEP-1, and the last one to Foreword vii rock art at sites Alero El Galpón and Cueva Grande. A first chapter on faunal analysis at the AEP-1 site describes the three diachronic assemblages identified with a careful description of taphonomy and human bone modifications. Relating faunal analysis with site formation and lithic studies, it discusses activities carried out at the site during the different periods. Rheids merit a chapter dedicated to their consumption, paleoenvironmental significance, and participation in social and symbolic spheres due to their exceptional proportion in the archaeofauna. Finally, there is a chapter that has already been mentioned on isotopic analysis of bone remains. Regarding lithic analysis, chapters cover a detailed description of assemblages recovered from the Lower Component (SU 6 and SU 4/5), from both a perspective of organization of technology, including raw materials provenience, and a perspective based on the design of retouched tools. Another comprehensive chapter deals with tool production and activities in the Lower and Upper Components studied through micro-wear analysis. The section closes with a chapter on rock art, which proposes a relative chronological sequence for pictographs and describes densely engraved panels of petroglyphs. The last group of chapters under Part III gives this book a twist. The chapter on patrimonialization renders a complete history of research in the area and describes its status and conflicts generated by different actors regarding its current use. It is relevant to discuss the place archaeology holds in our society. Two papers written by North American colleagues are evidence of the importance of South American sites such as AEP-1 bearing on the broader issue of the peopling of the Americas. One paints a general picture of the subject and the other compares Bonneville Estates Rockshelter to AEP-1 and sets the agenda for future work. In so doing, it addresses a variety of issues, some of which are obvious such as paleoecology, chronology, material record, past technology, subsistence, and settlement social organization, and others are not so evident, as disciplina traditions, formation of Paleoindian record and use of symbols. In no way is this chapter naïve regarding the early Patagonian record as the author fears. The last chapter starts with a synthesis of previous and current work at the site and goes on to discuss the interpretations and implications of these results. It ends with a discussion of what the evidence presented in the book means at a regional and continental scale. It gives a clear insight into the ideas sustaining research in this very Patagonian locality. I wish to thank the authors for the opportunity of writing this prologue that has given me the chance to read the book in full before being published. As any book that you find interesting this one has left me thinking about several issues. As mentioned above the significant question of the chronology of SU 6 will be further addressed through a new (although possibly very old) dating of the Mylodontidae rib. Pacific coast–Atlantic coast migrations, why would people share traditions on both sides of the Andes? How permeable was this divide and how strong were the shared traditions? Also, a subject that is most dear to me, are there unifacial industries in South America or are sites with unifaces a segment of a larger context including bifaces? Would people forget or ignore a skill such as bifacial flintknapping? How can we contribute constructively and with equality for those concerned in building a pan American view on the peopling? These are some of the thoughts haunting me viii Foreword after finishing my reading. Lastly, I am intrigued by a question whose answer you already know, what is the cover of the book like?
... 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). ...
... 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.
... On the other hand, considering a catastrophic death scenario, this sex ratio could indicate the formation of larger mixed-sex groups or the formation of groups of females with dominant males as well as temporary all-male social groups like in hippos or giraffes (Owen-Smith 1988;Eltringham 1999;Bercovitch and Berry 2015). However, even considering the narrow timespan represented at the site, more information is needed to confidently assess the possibility of individuals at the site being part of an unique social group and/or the potential human contribution to the accumulation (Fariña et al. 2014a(Fariña et al. , 2014bSuárez et al. 2014;Fariña 2015). Along this line, Tomassini et al. (2020) interpreted the Table 6. ...
Mylodontidae (Mammalia, Xenarthra) is a family of ground sloths widely distributed in the South American fossil record, with members also present in Central and North America. Within the Mylodontidae, Lestodon armatus is the largest species, with an estimated body mass of more than three tonnes. This work focuses on the enlarged lower caniniforms of L. armatus as possibly exaggerated sexually dimorphic structures. Lower caniniforms from the late Pleistocene of Argentina, Uruguay, and Bolivia were studied using specimens from seven palaeontological collections. The possible sexual dimorphism in the caniniforms and its implications regarding the existence of sexual selection was assessed through morphometric analyses. The results support the existence of sexual dimorphism in L. armatus. Sexual dimorphism in an exaggerated structure in a large mammal suggests the existence of sexual selection, via competition between males or female mate choice, resulting in the evolution of the dimorphic structure. In L. armatus, the enlarged caniniforms would correspond to males and could have functioned as armaments in intraspecific fights or ornaments for sexual display. Based on observations in extant mammals, a polygynous mating system is proposed as highly probable in L. armatus, although the existence or composition of social groups cannot be certainly determined.
... One rib (KI-1-50) showed "V shape" cut marks possibly made by stone tools. A similar cut mark (shape, angle, and rib area) was found on bones from Arroyo de Vizcaíno, Uruguay (Fariña, 2015). Some other bones showed gnaw marks mainly made by rodents and one specimen showed carnivore marks (KI-I-45). ...
We report here a new record of a megalonychid sloth from a late Pleistocene mammal assemblage from Cueva de Iglesitas (Mi.50), Caracas, Venezuela. This new site, the first with a Pleistocene fauna found in the vicinity of Caracas, is in a pristine geological and stratigraphic area and preserves previously untouched sediments containing fossils that provide important information about the late Pleistocene paleofauna and paleoenvironment of Caracas and the southwestern Caribbean region. A preliminary assessment of the relationship of this new sloth to other members of the Megalonychidae is presented.
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Current archaeological paradigm proposes that the first peopling of the Americas does not exceed the Last Glacial Maximum period. In this context, the acceptance of the anthropogenic character of the earliest stone artefacts generally rests on the presence of projectile points considered no more as typocentric but as typognomonic, since it allows, by itself, to certify the human character of the other associated artefacts. In other words, without this presence, nothing is certain. Archaeological research at Piauí (Brazil) attests to a Pleistocene human presence between 41 and 14 cal kyr BP, without any record of lithic projectile points. Here, we report the discovery and interpretation of an unusual stone artefact in the Vale da Pedra Furada site, in a context dating back to 24 cal kyr BP. The knapping stigmata and macroscopic use-wear traces reveal a conception centred on the configuration of double bevels and the production in the same specimen of at least two successive artefacts with probably different functions. This piece unambiguously presents an anthropic character and reveals a technical novelty during the Pleistocene occupation of South America.
This article is a response to Dillehay [2019. “Un ensayo sobre genética, arqueología y movilidad humana temprana.” Mundo de Antes 13 (2): 13–65] and Dillehay, Pino, and Ocampo [2020. “Comments on Archaeological Remains at the Monte Verde Site Complex, Chile.” PaleoAmerica.], who criticized our comments about Monte Verde-I and Chinchihuapi-I as well as our suggestion of the tightening of the age of Monte Verde-II [Politis, G. G., and L. Prates. 2018. “Clocking the Arrival of Homo sapiens in the Southern Cone of South America.” In New Perspectives on the Peopling of the Americas, edited by K. Harvati, G. Jäger, and H. Reyes Centeno, 79–106. Tübingen: Kerns Verlag]. They claimed that we purposefully ignored pertinent data to support our opinions, and that we made several mistakes when analyzing the evidence. In this article we demonstrate that we did not ignore any relevant data, and that the putative errors are in fact alternative interpretations based on the available data and recent studies about site formation processes.
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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.