Here we describe 31 fossil teeth, deposited in the paleontological collections of the Museo di Storia Naturale di Milano (MSNM), that come from the inland portion of the Mahajanga Basin, NW Madagascar, namely from the Sakahara Formation (classically known as Isalo IIIb subunit), which is dated back to the Middle Jurassic Bathonian stage. Based on detailed morphological characters, the eight morphotypes recognised herein are tentatively referred to four sauropod taxa: Archaeodontosaurus descouensi, ‘Bothriospondylus madagascariensis’, Lapparentosaurus madagascariensis, and an indeterminate specialised eusauropod, which may represent a new species, and the first evidence of a Bathonian diplodocoid in Madagascar. The identification of the teeth is corroborated by comparative examination of morphometric data. In this paper we provide evidence that Titanosauriformes were present in the Bathonian, on the basis of seven specimens referable to this clade. We also discuss in detail some dental characters that support the existence of a clear niche partitioning between the above mentioned taxa, that co–existed in the Malagasy Middle Jurassic terrestrial ecosystem. We finally hypothesise, for the first time, a direct correlation between the pattern drawn on the tooth crown by the enamel wrinkles and the feeding ecology of sauropod dinosaurs. The enamel wrinkles likely played a structural function: coarse wrinkles were associated to a diet composed mainly by hard foodstuff, whereas fainter wrinkles, which appeared in more derived morphologies, were associated to a diet composed by softer foodstuff.