Master Thesis A rich fish assemblage from the Miocene Al Jaghboub Formation, Marmarica Area, NE Libya

Abstract

A vertebrate fossils site has been discovered in Wadi Al Hash, 20 Km east of Tobruk city, NE Libya. This fossiliferous outcrop is the lower most horizon of Al Jaghboub Formation which was dated herein as early Miocene, late Burdigalian (17.25 Ma.) using (87 Sr/86Sr) radioactive isotopes for a Balanus shell, and the presence of some elasmobranches teeth remains. More than fifteen elasmobranch species and six teleost taxa were identified from the concerned horizon. Among the identified species such as Megascyliorhinus sp., Scyliorhinus sp., Paragaleus pulchellus, Rhizoprionodon fischeuri, Negaprion eurybathrodon, Rhynchobatus pristinus, Dasyatis aff. rugose, Dasyatis cf. gigas, Dasyatis cf. serralheiroi, Gymnura delpiti, Myliobatis sp., Mobula sp., cf. Epinephelus sp., Sparus sp., Diplodus aff. intermedius, Pagrus sp., cf. Dentex sp. and cf. Sphyraena sp. Most of the identified ichthyofauna herein are reported elsewhere around the Tethys and Paratethys (e.g. France, Portugal, Germany, Italy and India) confirming the connection between the Mediterranean and the Indian Ocean in that slice of time. This association clearly suggests that this facies was deposited in more or less deep marine environment under fairly subtropical climatic conditions. While the contemporaneous fossil site elsewhere in the Sirte Basin further southwest were deposited in shallow to marginal marine environments (e.g. Jabal Zaltan), this clearly suggests that the coastal shoreline was located further south during the early Miocene.