Biochronological data inferred from the Early Pleistocene small mammals of the Barranc de la Boella site (Tarragona, north‐eastern Spain)

Abstract

In 2007, remains ofMammuthus meridionalisand 334 lithic artefacts were recovered in level 2 of Barranc de la Boella. The presence ofM. meridionalisallows us to assign an age older than 700 ka to this level, which represents one of the few sites of this age with palaeontological remains associated with lithic industry. It also enables us to shed light on questions pertaining to the chronology and the biogeography of the earliest European human settlements. In this paper, the small mammals from the Barranc de la Boella site are described for the first time, with special emphasis on the arvicolines. The presence of Victoriamys chalineiandMimomys savini allows us to estimate the age of level 2. Level 2 of the Barranc de la Boella site ranges between the top of the Jaramillo subchron (0.99 Ma) and shortly after the Brunhes–Matuyama transition at 0.78 Ma, thus covering a time span of great importance for our knowledge of the earliest human occupations in Western Europe

Barranc de la Boella (Catalonia, Spain): an Acheulean elephant butchering site from the European late Early Pleistocene

“…The three BB localities are regarded as penecontemporaneous. The presence of Mammuthus meridionalis and the morphology of Mimomys savini molars from the top of Unit II at the three localities support the age of the archaeological deposits as lying between the top of the Jaramillo subchron (0.99 Ma) and shortly after the Brunhes–Matuyama transition at 0.78 Ma (Lozano‐Fernández et al, , ; Vallverdú et al , ).…”

On the fallacy of using orthogenetic models of rectilinear change in arvicolid teeth for estimating the age of the first human settlements in Western Europe

“…(Lozano-Fernández, Cuenca-Bescós, et al 2013, p. 96) Such logic (the 'vole clock' approach according to Martin 2014) is similar to the one used in geochronological methods based on natural radioactive decay, a stochastic process at the atomic level in that the probability that a given nucleus of an unstable isotope will decay is constant over time (Masini et al 1999a(Masini et al , 1999b. For this reason, the use of this argument in biostratigraphy reminds -although reversed -the title of the comedy film 'If it's Tuesday, this must be Belgium', directed in 1969 by Mel Stuart: if the 'biochronological method' of and Lozano-Fernández, Bañuls-Cardona, et al (2014) proved valid, it would imply that the length of the first lower molar tooth of M. savini increased in a way as regular and predictable as the one of those old packaged sightseeing tours designed for time-sensitive travellers, where the nonplussed tourists were expected to rush from one country to another in a short time interval (and eventually became confused about the country in which they were). For a discussion on the weakness and inconsistency of the use of this reasoning in biochronology, see Braga and Rivas (1986).…”

“…In fact, the rectilinear equations used by Lozano-Fernández, , and Lozano-Fernández, Bañuls-Cardona, et al (2014) for deriving chronological estimates assume that each mean Lm1 value of M. savini would correspond to a single numerical age in south-western Europe during the late Early Pleistocene (i.e., the 'if this is Belgium, it must be Tuesday' argument). According to Palmqvist et al (2014), such reasoning represents a case of 'fallacy of hasty generalization' (see Walton 1999), as it implies that: (1) each of the samples of M. savini taken consecutively through the Atapuerca TD section has a single mean tooth length and a given age; (2) any sample whose mean Lm1 value is identical to one of the TD samples should have the age of the latter and (3) if a sample of M. savini has a different mean tooth length, its age could be interpolated (or extrapolated) using the function that relates tooth size and sample age in the Atapuerca TD sequence.…”

“…The falsity of this reasoning (i.e., that two samples with identical tooth size values could not have different ages) is clear, because although a couple of samples from the Atapuerca TD sequence show the same mean Lm1 values, TD4 (3.43^0.14 mm) and TD6-3 (3.43^0.17 mm), their ages are 1.01 and 0.86 Ma, respectively (Lozano-Fernández, Cuenca-Bescós, et al 2013: Table 1). Moreover, with independence of the storyline of the film of Mel Stuart (or the logic of the biochronological method of Lozano-Fernández, , and Lozano-Fernández, Bañuls-Cardona, et al (2014), it should be noted that any travel may be affected by delays and the tourists might not have arrived to Belgium on Tuesday, as programmed (in our case, the age of the samples used for deriving the equations of site age on tooth size can be incorrect, as noted by Palmqvist et al 2014 and discussed in more detail later).…”

“…In addition, the mean Lm1 values of levels TD4 to TD6-1 used by for deriving their rectilinear Equations (as well as the numbers of specimens on which they are based) differ from other datasets. For example, in the case of TD4, the level for which the discrepancies between datasets are greater, the mean Lm1^s values published are: 3.43^0.14 mm (N ¼ 12, Lozano-Fernández, Cuenca-Bescós, et al 2013), 3.38^0.14 mm (N ¼ 5, Martínez et al 2014), 3.34^0.14 mm (N ¼ 12, Lozano-Fernández 2014) and 3.34 mm (s not available; N ¼ 10, Lozano-Fernández, Lozano-Fernández, Bañuls-Cardona, et al 2014). In which concerns the Orce sites, the values used by for BL-D and FN-3 are 3.23^0.11 mm (N ¼ 34) and 3.28^0.09 mm (N ¼ 42), respectively.…”