Figure 1.
BAT-1 geographic, geologic and taphonomic context.
A, Distribution of the three sedimentological units and fossil sites of Cerro de los Batallones in aerial view (Modified from Pozo et al. [17]). BAT-1 = Batallones-1, BAT-2 = Batallones-2 and so on. The Madrid Basin is highlighted in grey in the map of Spain; B, Geological sketch (vertical section) of BAT-1 showing the lower level assemblage (LLA) and upper level assemblage (ULA) (Modified from Pozo et al. [17]). Because the ULA was mostly eliminated during the sepiolite quarrying, we provide a reconstruction (dotted lines) based on observations from other localities of Cerro de los Batallones. The sketch is not to scale; C, BAT-1 LLA bone concentration. In some areas of the excavation, bones appeared tightly packed and in contact with one another; D, Partial skeleton of the hyaena Protictitherium crassum. Mean skull length of Protictitherium crassum from BAT-1 LLA is 13.5 cm.
Table 1.
Main taphonomic features of the large mammal remains from BAT-1 LLA and ULA.
Table 2.
Number of Identified Specimens (NISP), Minimum Number of Elements (MNE) and Minimum Number of Individuals (MNI) of the large mammal taxa recovered in BAT-1 LLA.
Figure 2.
Skeletal element proportions expressed as Relative Abundance (%Ri) in BAT-1 LLA.
Transport groups are given in roman numerals following Voorhies [29] and Behrensmeyer [30]. Group I: inmediately transported elements, Group II: elements transported gradually, Group III: lag deposit. Group I-II is an intermediate category. Note that the y-scale changes across the plots. Vert = vertebra, sterne = sternebra, sesam = sesamoid, patel = patella, phal = phalanx, scap = scapula, metap = metapodial, tib = tibia, fem = femur, rad = radius, hum = humerus, pelv = pelvis, mand = mandible.
Table 3.
Skeletal completeness for BAT-1 LLA well-defined taxa.
Figure 3.
Spatial distribution of the fossil material from BAT-1 LLA.
A, Rose diagram. Note that Rayleigh’s test points to a preferred orientation of the fossils (i.e., p<0.01); B, Contour diagram of data presented in a stereographic projection, the scale is indicative of the percentage of fossils showing a particular plunge and trend. The analyses are based on fossils showing a longer axis.
Figure 4.
Bone modifications due to sediment compaction in BAT-1 LLA.
A, Bone collapse in femur B-7056 (top) and humerus B-2721 (bottom) of Machairodus aphanistus. Note that a fragment of another bone is encrusted in the distal part of the femur diaphysis (grey arrow). Collapse in that area of the femur was probably caused by the bone-bone contact; B, Deformation of Protictitherium crassum skulls. Left: skull B-2804; center: skull B-2802; right: skull B-2889.
Table 4.
Number of Identified Specimens (NISP), Minimum Number of Elements (MNE) and Minimum Number of Individuals (MNI) of the large mammal taxa recovered in BAT-1 ULA.
Table 5.
Expected features of fossil assemblages accumulated under different scenarios.
Figure 5.
Sequence of events in the formation of BAT-1 LLA and ULA.
A, Carnivorans intentionally entered into the cave attracted by trapped/death animals or water; B, Episodic floods filled the cavity and buried remains in different articulation stages; remain orientation was the result of their adaptation to a colluvial breccia; elements in the chamber are protected from different taphonomic alterations; repeated carnivoran entrances through time; C, Lithostatic pressure produced breakage, collapse and deformation of remains; final stages of the filling of the chamber: the location is not a carnivore trap anymore; D, Deposition of elements from the ULA in an uncertain taphonomic context (entrapment of herbivores?).