The northeastern part of Algeria is characterized by Meso–Cenozoic fossiliferous deposits. All the previous studies have been focused on invertebrate and vertebrate body fossils from this region. In the present paper we provide the first ichnological study from the region of Ouenza, Tebessa Wilaya (northeastern Algeria). An ichnoassemblage composed of eight ichnotaxa, namely cf. Archaeonassa isp., Arenicolites isp., Diplocraterion isp., Helminthopsis isp., Palaeophycus tubularis, Skolithoscf. linearis, cf. Taenidium isp., and Thalassinoides isp., reported from the lower Langhian (Middle Miocene) of Aïn Sidi Salah locality (Tebessa Basin) is discussed. These trace-fossils belong to the Skolithos and proximal Cruziana ichnofacies indicating deposition within a shallow marine (littoral). The large size of Thalassinoides suggests well-oxygenated setting, under moderate- to high-energy conditions, with occasional storm events. Keywords: trace-fossils, paleoenvironments, shallow marine, Middle Miocene, Tebessa.

The late Miocene marginal marine deposits of the Sikkak area (Tafna Basin, northwestern Algeria) encompass moderately diversified invertebrate trace fossils preserved mainly as epichnia. The present study documents for the very first time the trace fossils occurring in this area, where 16 ichnotaxa, dominated by post-depositional domichnial, repichnial and fodinichnial components, are reported: ? Bifurculapes isp., Diplocraterion isp., Helminthoidichnites isp., ? Kouphichnium isp., ? Megagrapton irregulare , Ophiomorpha annulata, Ophiomorpha cf. nodosa , Oravaichnium isp., Palaeophycus isp., Planolites cf. beverleyensis , Planolites montanus , Ptychoplasma isp., Skolithos isp., S. linearis , Thalassinoides isp. and T. suevicus . The main producers of the studied trace fossils are arthropods (crustaceans, limulids, insects), annelids (polychaetes, phoronids) and bivalves. These traces are commonly associated with sedimentary structures that are caused by hydrodynamics, suggesting high-energy conditions and opportunistic colonization within a marginal marine environment (i.e. backshore to foreshore), and corresponding to the Skolithos ichnofacies. The crustacean trace ? Bifurculapes and the limulid trackways Kouphichnium are reported herein for the first time in Algeria. Sedimentological data suggest an imbricated sandstone channel within a marginal marine setting and subaerial exposures indicated by mud-cracks. The foraminiferal assemblage, dominated by shallow marine species, therefore suggests a Tortonian age for these deposits.

The ichnological study of the Djebel Bouarif Cenomanian deposits (Northern Aurès Range, Algeria) revealed relatively abundant and diverse sclerobiont communities that are preserved in corals, bivalves and gastropods. Fossil traces are dominated by exceptionally preserved Gastrochaenolites, often with tracemakers (bivalves), which are preserved in situ, Entobia, and Maeandropolydora. Other borings are rare and are represented by a single specimen of Rogerella, Nihilichnus, and Spirolites. Among sclerozoans, encrusting juvenile oysters and non-oyster bivalves (Pseudolimea? granulata) are the most abundant groups. Other epibionts, such as gastropods and polychaetes (Glomerula serpentina), are less common; dwarf gastropods were located on a single oyster Costagyra olisiponensis, whereas Glomerula specimens were clustered on the lower and upper surfaces of coral Aspidiscus cristatus. Gastrochaenolites with original tracemakers and all the epibionts studied herein have not been described from the Djebel Bouarif Cenomanian deposits to date. The rare occurrences of Spirolites and Nihilichnus are reported from Algeria for the first time.