CHONDRICHTHYAN TEETH FROM THE MENUHA FORMATION (UPPER CRETACEOUS, SANTONIAN) OF SOUTHERN ISRAEL AND THEIR IMPLICATIONS FOR PALEOENVIRONMENTAL RECONSTRUCTIONS

Exposures of the Menuha Formation (Santonian, Mount Scopus Group) in the Makhtesh Ramon region of the southern Negev have produced numerous chondrichthyan teeth. The isolated teeth represent at least 10 different species: Squalicorax pristodontus (Agassiz, 1843), S. kaupi (Agassiz, 1843), Scapanorhynchus rapax (Quaas, 1902), S. raphiodon (Agassiz, 1843), Cretalamna appendiculata (Agassiz, 1843), Carcharias cf. samhammeri (Cappetta & Case, 1975), C. cf. C. holmdelensis (Cappetta & Case, 1975), Cretoxyrhina mantelli (Agassiz, 1843), and two other fish (Hadrodus priscus (Leidy, 1857) and a pycnodontiform). The majority of teeth were contained within a glauconite-rich, yellow-brown, soft chalk that included oysters, trace fossils (Planolites and Thalassinoides), and phosphatic peloids and foraminifera. West of the Makhtesh Ramon structure, a marine conglomerate contained a high density of isolated “sand tiger” and Scapanorhynchus sp. teeth. The teeth were collected mainly through surface sampling, with only a few found using sieving techniques. Many of the teeth are well preserved, showing signs of complete root, cusplets, laminations/folds, and nutrient grooves, depending on the characteristics of the shark species. Although little is known about the habitual ranges for shark species, a few have been described as having wide ranges in nearshore and offshore environments. Some are compared to extant relatives, such as Scapanorhynchus sp. whose extant-related species Mitsukurina owstoni occupies outer continental shelf areas. Combining both the plausible habitats of each shark species and the lithology of the surrounding rock, the Late Cretaceous paleoenvironment was likely a temperate to subtropical continental shelf. This environment would have also included other marine life to sustain the shark population, such as: plesiosaurs, ichthyodectids, mosasaurs, shrimp, squid, and a variety of other fish. With little to no published material describing the chondrichthyan fauna of the Menuha Formation, this data will improve interpretations of its paleoenvironment within the Makhtesh Ramon region, southern Israel.