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The Pliocene lacustrine infill of Camp dels Ninots maar (Girona, Spain) hosts an exceptional record of complete articulated skeletons. Here we present the taphonomical description of 22 fossil water frogs recovered from the Pit 7/8 of Can Argilera Sector. Description of their skeletal taphonomy is done on the basis of their distribution, completeness, articulation and limb position, and by establishing comparisons with the late Miocene site of Libros (Spain). Microscopic examination shows no evidence of digestion and absence of weathering. Mass mortality or any environmental stress-induced factors cannot be ruled out, but natural death seems to be the most probable. Limited time of decay prior burial seems to be the main pattern explaining the relatively high degree of articulation and completeness. Floatation is not to be disregard for some more (proximally) disarticulated specimens. Taphonomical patterns document two types of sub-environments inside a cool and deep lake, suggesting a more complex depositional scenario for Camp dels Ninots than the ones described in others similar Konservat-Lagerstätten. [ABSTRACT FROM AUTHOR]

Climate conditions during the Pliocene Climate Optimum (3.2 - 2.5 Ma) are significant due to their proposed correspondence with future climate. There are various difficulties involved in obtaining terrestrial temperatures for this period, so new sources of information are therefore important. This work proposes a new approach based on frog body size, facilitating a palaeoclimate reconstruction of the palaeontological site of Camp dels Ninots (Caldes de Malavella, NE Spain), a Pliocene Konservat-Lagerstatte, dated at around 3.2 Ma. For this purpose, an extensive database of current populations of the genus Pelophylax from across Eurasia has been generated making it possible to establish a correlation between frog body size and eco-climate parameters such as temperature, precipitation rates and real evapotranspiration. Eco-climate values were obtained using OLS regression models and compared with previous palaeoclimate reconstructions from other archaeo-palaeontological sites of interest (Barranco Leon and Fuente Nueva 3, SE Spain). Our new proxy results in a palaeotemperature of 14.3 ± 2.6°C and a palaeoprecipitation rate of 846.8 ± 165.4 mm; according to primary productivity values, a 'Summer-green broad-leaved forest'-like biome is proposed for Camp dels Ninots, in line with previous palaeobotanical studies. The new values generated for the other sites follow the same trends as previous reconstructions, although with lower values in most cases, especially in terms of temperature. This method is a promising new approach to complement previous palaeoclimate reconstructions and could also generate new data. [ABSTRACT FROM AUTHOR]

In recent years several studies have been carried out to test the validity of Bergmann's rule for amphibians, and have generated varying results. Due to the lack of agreement on this topic, here we examine the relationship between climate and body size for one anuran species (Bufo calamita, commonly known as the natterjack toad) with a new methodological approach that uses the fossil record as the data source. We analysed bones from two archaeo‐paleontological sites located close to each other in the Sierra de Atapuerca (Burgos, Spain) that together encompass more than one million years from Early to Late Pleistocene. We used ordinary least squares (OLS) simple regression models to integrate body size and palaeoclimatic data (temperature and precipitation) and describe the relationship between the amphibian's body size and climate along the entire temporal gradient. We found the body size of B. calamita to be negatively related to the mean annual temperature and the mean temperature of the coldest month, and positively related to December‐to‐February precipitation. The climatic influence was stronger in females, which were smaller than males in most cases, and therefore an inverse sexual size dimorphism pattern was found. Juvenile individuals or the limited sexual size dimorphism of this species may be causes of this unusual pattern. Bufo calamita populations showed a clear Bergmann cline during the Pleistocene period, and winter stands out as the most influential season. Although this new methodology can only be used to describe patterns, we discuss several mechanisms that could explain our results. We propose that starvation resistance and delayed maturation are the main causes for this increase in size in periods with cooler winters, and a fecundity‐related hypothesis to explain why climate has a greater influence on female body size. [ABSTRACT FROM AUTHOR]