[en] A neotaphonomical study in a closed context is proposed through the analysis of a modern faunal collection deposited on the cave floor surface of Mas des Caves, at Lunel-Viel (Hérault) during a known period of time. Almost 1640 bone and dental remains represent nearly 26 small to medium-sized species. Taxonomic diversity, skeletal representations, traces on bones and age structure of the main species are described. Such criteria allow to discuss the origin of this bone collection that can serve as a referential to better understand natural accumulations in the subterranean environment.IntroductionThe question of site formation and its fossil accumulation is one of the most important taphonomic issues with important implications for palaeoecological, zooarchaeological and anthropological interpretations. It raises questions about the chronology, the number of events and the duration of deposition of bone assemblages recorded in a fixed (unit, layer, level) and variable (karst, fluvial, lake, marine, dune, source) sedimentary context, i.e. before, during and even after burial. The need for an actualistic approach and the development of modern referentials are then important, but still limited, especially in karstic environments. Such studies reveal the juxtaposition of events resulting from a mixture of remains (amalgam or palimpsest) of different origins and agents, raising questions of equifinality, but above all questions of chronological resolution, which can have major repercussions on our palaeobiological or palethnological interpretations.Within this problem, we present here neotaphonomic observations on faunal remains deposited on the surface of a cave floor during a known period. The resumption in 2019 of a research project in the Mas des Caves cave, which had been closed since the excavations of E. Bonifay (EB, from 1962 to 1982), made it possible to collect a large number of bone and dental remains deposited on the current surface of the cave. This means that the accumulation represented by modern species is recent, with an accumulation of a known period.In general, the understanding of the " 3Ds ": diversity (sensu taxonomic), density (sensu quantitative) and duration (sensu time averaging) of a faunal accumulation, is fundamental in taphonomic studies and makes it possible to explain the origin of bone assemblages in underground environments. The proposed study constitutes a rather rare reference in a pre-burial context, illustrating the agents and actions that can exist and be mixed in a cavity. Trough time faunal deposition on cave ground can often be largely mixed with invertebrates (e.g. gastropods) and vertebrates (micro- to macro-fauna), sometimes with witnesses of the passage of humans or their occupations or those of other troglophiles (bears, hyenas, foxes, etc.).I | The Mas des Caves and study materialThe caves of Mas des Caves, in Lunel-Viel (Hérault), are located in the south of France, between Nîmes and Montpellier. Developed from Miocene molasse strata, they are long linear galleries: cave n° 1 (LV I) is the most important, extending into cave n° 4, which is currently inaccessible (LV IV), beyond a doline that is currently completely closed (the original entrance to these caves). LV I was discovered in the early nineteenth century by an artificial bore (discovery entrance) and extensive fieldwork was carried out by Eugene Bonifay yielding a rich and varied fossil and lithic material. The site has since been closed and it was during the revival of research in 2019 (dir. J.-Ph. Brugal) that the surface was cleaned and a systematic collection of modern bone and dental remains lying on the surface was carried out. This faunal collection thus represents an interesting example of recent accumulation over an estimated period of 40-50 years. Most of this collection (66.8%) comes from the excavation area (about 300 m2, from sectors 1 to 5: fig. 1). The deeper sector (opposite to the natural entrance: doline) shows a small bat colony of Rhinolophus ferrumequinum and bioturbation by badgers. We chose to combine all the surface material, considering that the deposits would have formed a single set if this had been a smaller cavity.We identified 1639 bone and tooth remains (pl. 1). The taxonomic diversity is significant with 9 major zoological groups ranging from micro-, meso- to macrofauna (Table 1) with at least 26 species represented. Leporids and carnivores (rabbit, cat, fox, and badger) are the most abundant, followed by rodents and especially birds, slightly less abundant but with greater species richness (11 species, about 9 %). Almost 26 % of the avian remains and 9 taxa show evidence of carnivores in the form of tooth marks, punctures and gnawing (pl. 2). Other groups are more anecdotal (about 4 %: reptiles, amphibians, chiroptera, herbivores). Most of the surface collection (70.6 % of NISP) consists of lagomorphs (Oryctolagus cuniculus) and domestic cats (Felis silvestris catus) and wild carnivores (Vulpes vulpes, Meles meles). Only these four taxa will be studied in more detail.II | Main mammalian taxaII.1 | Oryctolagus cuniculusThe rabbit is the most abundant species with nearly 640 remains representing 24 adults (n=557) and 9 juveniles (n=81). All skeletal elements are present with many isolated teeth, coxae, femurs, tibias and metapodials (fig. 2). Long and flat bones are abundant (45 % of total), with more hindlimb bones (c. 76 %) than forelimbs (c. 24 %) and a good balance between left and right elements. Nearly 130 bones are broken and associated with carnivore tracks (c. 34 %, fig. 3, pl. 3).II.2 | Vulpes vulpesThis small carnivore is abundant with 242 tooth and bone remains (MNI = 3 adults and 2 juveniles) and all skeletal elements are present (fig. 4) with many vertebrae and ribs and isolated teeth; there is an almost complete skeleton. Bone fractures are limited and associated with relatively more tooth marks (mostly punctures): 12 in the adult and 18 in the juvenile.II.3 | Felis silvestris catusThe domestic cat is the second carnivore species represented. Its remains are relatively sparse, consisting of 143 elements from different parts of the skeleton, with 137 bones from adults (3 individuals) and 6 from juveniles (1 individual) (fig. 5). Cranial and distal elements are predominant and long bones are a minority, often complete. When bones are fractured, tooth marks are associated with them. II.4 |Meles melesTwo individuals are present: one is a sub-complete sub-adult skeleton found near the site discovery entrance, in the process of decay (pl. 4), the second is a young individual (est. 2 months old). The skeletal distribution is homogeneous (fig. 6). Only the juvenile mandible shows punctures.III | Causes of accumulationThere are two possible causes: natural death and predation. The first concerns individuals that died naturally in the cavity used as a living space, with the presence of burrows (especially badgers in the deeper zone). The presence of skeletons of the same individual (fox, badger) supports this hypothesis, and it is probably the case for some other taxa (e.g. bats, snakes and frogs).The second cause is predation, either active (hunting) or passive (scavenging). The fox is the main predator, capable of preying on both birds and rabbits, and of accumulating their remains in the cavity that also serves as its den (fox cub), without excluding the actions of the cat and the badger. The cases of fish or domestic ungulates suggest that pieces were stolen from local human waste and imported into the cave. Bone modifications are present in all four main taxa, with the highest frequency in the rabbit (fig. 7).The dimensions of tooth marks, such as punctures, are consistent with those of small carnivores such as foxes, particularly on the long bones and vertebrae of adult rabbits. Skeletal representation is variable according to context and agent. A multifactorial analysis (AFC) based on the main skeletal categories: cephalic (isolated teeth are excluded), axial, forelimb and hindlimb, basipodial, metapodials and phalanges, was performed on a collection of leporids of defined origin (Figure 8). Axial elements are dominant in the natural assemblage (Le Regourdou), whereas distal limbs are abundant in the lynx accumulation (El Acebuche, La Olovilla). More hindlimb bones are present in the collection made by the Eurasian Eagle Owl (Middle Palaeolithic deposit of Caldeirao), and our LV I collection is closed to this pattern, as in the Spanish site of Teixoneres, which shows a mixed origin (raptor, small carnivore and very occasionally human). Two other sites (Solutrean deposit of Caldeirao, Mousterian site of Canalettes) yield more cranial, axial and hindlimb elements, with clear human actions on the bones as cut-marks, cylinders, burning. Such processes are missing in the collection of LV I and the presence of rabbits result both of natural and predatory origin.ConclusionThis paper has analyzed a modern bone assemblage deposited on a cave floor over a known period of time, estimated at 40-50 years. Its aim is to understand the origin of this accumulation and to clarify some behavior of modern small carnivores. The origin of the material and the species is twofold, both generated by natural processes, but also by predation, mainly by the red fox, followed by a possible confrontation between the three carnivore species present. It is a neotaphonomic study that constitutes a rare example and proposes an interesting referential because we know the duration of this ante-burial faunal accumulation. The collection - diversified and quantitatively important - of the Mas des Caves LV I questions the temporal, contemporary dimension of the processes of site formation and bone stock production. The knowledge of the duration of faunal accumulations seems essential to better characterize what are often called palimpsests, but which in fact represent a potential mixture and amalgamation of series of events, dissociated or complementary.

[fr] Une étude néotaphonomique en contexte fermé est proposée avec l'analyse d'une collection faunique moderne accumulée en surface dans la grotte du Mas des Caves, à Lunel-Viel (Hérault) pendant une période de temps connue. Près de 1640 restes osseux et dentaires représentent au moins 26 espèces de petite à moyenne taille. La diversité taxinomique, les représentations squelettiques, les traces sur les ossements et les âges des principales espèces sont décrits. Ils permettent de discuter de l'origine de cet ensemble pouvant servir de référentiel intéressant pour la compréhension des accumulations naturelles en milieu souterrain.