A key site for inferring the timing of dispersal of giant deer in Sardinia, the Su Fossu de Cannas cave, Sadali, Italy

Abstract

Su Fossu de Cannas (SFC) cave is one of several known cavities in the Sadali plateau in Sardinia, Italy. The\ud evolution of the cave is the result of complex erosional and deposital processes that occurred during the\ud Neogene and Quaternary. A fossiliferous cemented conglomerate, containing various deer remains, now\ud forms the ceiling of a cavity (tunnel). The faunal remains belong to a large cervid, which show some\ud morphological affinity with large deer that have an endemic Sardinian lineage (Praemegaceros sardous\ud ePraemegaceros cazioti). Palaeoecological data based on some peculiar features and the large size of the\ud SFC deer suggest that it is the most primitive Megacerine found in Sardinia to date, and the first\ud representative of the endemic lineage. The 450 ka UeTh age for the flowstone capping the fossiliferous\ud layer defines: the end of sedimentation in which Sadali deer remains are preserved; and the dispersal\ud from the mainland of the ancestor of the endemic Sardinian Megacerini. Stratigraphic and micromorphological\ud analyses of the cave deposits allow the reconstruction of the timing of the cave's development\ud throughout the Pliocene to the Holocene

Genomic analyses of the extinct Sardinian dhole (Cynotherium sardous) reveal its evolutionary history

“…We found that the demographic histories of the two pseudo-hybrids ( Fig. 4C) are almost identical, indicating that gene flow ceased after the Middle Pleistocene, a timing that is also consistent with a number of publications in which different faunal complexes that populated the island were taken into consideration 18,20,33 . Further, we determined that estimates using Sardinian dhole/AHD and Asian dhole/AHD hybrids gave an interval between 1.05 Ma and 300 ka for the cessation of gene flow between AHD and the two dhole lineages (Fig S5).…”

“…Given this complex scenario, a number of earlier studies considered the Sardinian dhole as a subgenus of Xenocyon, Cuon, or a derived form of Canis 3,10-12 that might have reached Sardinia and Corsica by sweepstake or passive dispersal at the transition between Early and Middle Pleistocene 4,20 . This phenomenon is especially feasible during periods of fluctuation of the sea level and have been known to contribute to the faunal turnover in Sardinia 4,18,20 .…”

“…Nevertheless, Pleistocene mammals of Sardinia are currently divided into two major faunal complexes, an older one (Nesogoral Faunal Complex) and a younger one (Tyrrhenicola Faunal Complex) divided by the end of the Early Pleistocene 18,19 . Given this complex scenario, a number of earlier studies considered the Sardinian dhole as a subgenus of Xenocyon, Cuon, or a derived form of Canis 3,10-12 that might have reached Sardinia and Corsica by sweepstake or passive dispersal at the transition between Early and Middle Pleistocene 4,20 . This phenomenon is especially feasible during periods of fluctuation of the sea level and have been known to contribute to the faunal turnover in Sardinia 4,18,20 .…”

Insular mammalian fauna dynamics and paleogeography: A lesson from the Western Mediterranean islands

“…In particular, it has been hypothesized that the ancestors of Cynotherium (a descendent of a lycaon-like dog, Xenocyon lycaonoides, believed to have had some swimming abilities as the modern lycaons have) and Praemegaceros might have reached the island by the end of the Early Pleistocene when the glacial cycles of the so-called Mid-Pleistocene Revolution (Maslin & Ridgwell 2005) were particularly pronounced and the increased amplitude of sea-level fluctuations led to the temporary emergence of limited areas of the continental shelf, reducing the width of the sea-arms that separated the Corso-Sar-dinian Massif from the mainland (Palombo 1985). The assumption is consistent with the hypothesis that the Sardinian wild canid and giant deer (whatever their putative ancestor should be) stemmed from late Early Pleistocene continental stocks (Croitor et al 2006;van der Made & Palombo 2006;Madurell-Malapeira et al 2015;Melis et al 2016). It is interesting to note, however, that in the Orosei 2 FsC, good swimmers like elephants are missing, though it has been hypothesized that the ancestor of Mammuthus ex gr.…”

Organization of Squamata (Reptilia) assemblages in Mediterranean archipelagos

“…These factors were of similar importance and, for this reason, large and orographically heterogeneous islands (e.g., Crete, Mallorca, Sardinia, and Sicily) show relatively species‐poor assemblages compared with Ionian or Aegean islands (e.g., Korfú or Samos), which are smaller but situated close to the continent. Crete, Mallorca, and Sardinia were completely isolated by the end of the Messinian age and had impoverished and unbalanced faunas until the Late Pleistocene—Holocene (Krijgsman, Hilgen, Raffi, Sierro, & Wilson, ; Melis, Palombo, Ghaleb, & Meloni, ; Meulenkamp, Wortel, Wamel, Spakman, & Strating, ). Although currently situated very close to the continent, Sicily possibly had its colonization hindered by the fragmentation of Calabria into several islands until the mid‐Pleistocene, and the continuous persistence of the Strait of Messina throughout the Late Glacial (Marra, ; Palombo, ).…”