Filling the gap in knowledge of early Miocene continental molluscs of southwest Europe: gastropods from Ribesalbes-Alcora Basin (Spain)

Abstract

such as those of Vallés-Penedés, Ebro, Calatayud-Daroca, Teruel, Duero and Tajo, as well as smaller ones such as Cabriel, Fortuna, Guadix-Baza and Granada (Agustí 2018). Continental sediments of Aragonian age (end of the early Miocene to middle Miocene; mammal biozones MN4 to MN7/8) are represented in many of these basins (Agustí 2018). While mammal associations have been studied extensively in several palaeontological sites, the malacological record is comparatively poor documented. The few studies carried out on the malacological assemblages recorded in sediments today attributed to an Aragonian age are to some extent outdated (Vilanova y Piera 1859; Royo Gómez 1922, 1926, 1928; Jodot 1959). Also, many of sites and faunas documented in these works could not be precisely located. The available references accurately located and dated correspond to sites attributed to the middle Aragonian of the Tajo Basin (Truc 1977) and the upper Aragonian of the Duero Basin (González Delgado et al. 1986, Civis et al. 1989). The references from the early Aragonian are practically inexistent and correspond to isolated cites or recent multidisciplinary studies in the Ribesalbes-Alcora Basin (Peñalver et al. 2016, ÁlvarezParra et al. 2021). In line with the above, the available data on the mala cological content of the sediments of the Ribesalbes-Alcora Basin (Fig. 1A) are mostly old and very scarce. The first one corresponds to Vilanova y Piera (1859) who studied the materials in the “Balsa de Fanzaraˮ (the classical name for the Cenozoic sediments of the basin) and the nearby area of Alcalá. He cited the generic presence of “lymneasˮ, “planorbis” and “helicesˮ (Vilanova y Piera 1859: p. 44), and more specifically a single specimen of Planorbis rotundatus Brongniart, 1810 from the “Balsa de Fanzara”, which is shown on a plate alongside with four species belonging to the Alcalá area. Royo Gómez (1922) included a brief reference to the sediments of the studied area correcting the determination of Planorbis rotundatus to