The Maltese islands during the quaternary : a holistic review of known terrestrial pleistocene to holocene sites and a new faunal complex scheme for Malta

Abstract

The Pleistocene Epoch is one of the least understood and comparatively sparsely-studied time periods relating to the Maltese archipelago. Although remains of Pleistocene terrestrial faunas have been recorded in Malta as far back as the 17th Centurv, it was only during the latter half of mid-19th Century that proper scientific research . started to shed some light on this obscure period of time. However, most of the works produced concentrated on describing the discovery of particular sites and their fossiliferous contents, and a comprehensive analysis which outlines the varying prevailing ecological conditions within the Maltese Islands during the Pleistocene, is even at present day, conspicuously lacking. Moreover, most of the contemporary works produced on the subject tend to concentrate on a very limited number of sites or one location in particular, that of Ghar Dalam. This present research has adapted a more comprehensive approach with the aim of creating a holistic interpretation of Maltese sites and their fossiliferous contents, with particular emphasis on Pleistocene ones. All known Maltese Pleistocene sites mentioned in published literature, have been thoroughly analysed, and a stratigraphic sequence with associated organic remains has been created for each respective site. This current comprehensive analysis of known Maltese Quaternary sites has never been attempted before, and over seventy sites have been identified distributed throughout Malta and Gozo. Since Maltese Pleistocene faunas comprising terrestrial vertebrates and gastropods, are widely accepted as being related to those of neighbouring Sicily, a comparative analysis with the more established Sicilian faunal complexes has also been undertaken. The palaeoecology, palaeogeography, dispersal routes, and other topics of a palaeontological nature, which had in tum direct consequence on the nature and palaeoecology of Maltese Pleistocene faunas, have also been discussed. Although exhibiting similar characteristics to those of Sicily, the newly-proposed Maltese faunal complexes feature also particular local variations which differ from Sicilian ones. The holistic detailed analysis adapted in the present research has permitted the recognition of at least five faunal complexes, four of which are probably linked with possible dispersals from outside the Maltese Islands. These dispersals were consequently followed by prolonged periods of isolation which led to endemism. A number of stages, some of which feature only one taxon, have been also identified. The designated terminology adapted for these new Maltese fauna! complexes is based on the type localities from where the faunal assemblage typical to each faunal complex had been excavated. The designated new Maltese faunal complexes include, from the earliest and oldest, (a) the Mnajdra / Wied il-Hesri / Benghisa Faunal Complex, (b) the Tal-Gnien Fissure / Maghlaq Cave Local Faunal Assemblage (LF A), ( c) Middle Cave Local Faunal Assemblage, (d) the Wied Incita / Tal-Herba Fissure 2 / Ghar Dalam Bone Breccia Layer Faunal Complex, (e) and the Microtus (Terricola) melitensis Ghar Dalam Fauna! Complex. Recognised faunal stages/assemblages, designated as the Hippopotamus-only Local Faunal Assemblage, the Mriehel Girls Grammar School I Ghar Dalam Upper Clay and Pebble/Small Boulder Layer (Post-Glirid I Pre-Microtus Terricola) Stage, and the Deer-only Local Faunal Assemblage, probably occurred at a time period between the Wied Incita / Tal-Herba Fissure 2 / Ghar Dalam Bone Breccia Layer Fauna Complex and the Microtus (Terricola) melitensis Ghar Dalam Faunal Complex. Other stages postdating the latter mentioned faunal complex, were identified as the (a) Ghar Dalam Early Post-Proboscidean Stage, (b) Prehistoric or Apodemus sylvaticus Stage, and (c) the Historic/Cultural or Rattus rattus Stage. The site of Ghar Dalam, which is presently the Maltese site known to have contained the most extensive sequence of Pleistocene/Holocene sediments, has been also systematically investigated and its stratigraphic terminology reviewed accordingly. Problems effecting the study of the Maltese Pleistocene, the history of Maltese Pleistocene studies, etymology, dispersal events, and dating assigned to proposed Maltese faunal complexes, have been also discussed.