Morphological studies and analysis of gut contents indicate that two species of montane Ethiopian frogs are specialized for selective feeding on terrestrial gastropod mollusks. Certain bony elements of the skull, such as the palatines and prevomers, are reduced and deflected dorsally, while lateral elements of the maxillary arch, such as the quadratojugals and maxillaries, are expanded. The nasal apparatus in both species is situated in an extreme anterior position. The two species are removed from the genus Karrina Girard and placed in the genus Tom'erefla Ahl. Morphology of the head suggests that these frogs grasp mollusks with their jaws, pull them from the substrate, and swallow them whole. The sensoiy cues which trigger feeding are as yet unknown. Apparently, these frogs are the first terrestrial vertebrates known to feed exclusively on whole mollusks, without crushing them or removing the soft parts from the shell.
Multiple associations of fossil snails with dinosaur coprolites demonstrate that snails and dinosaurs not only shared ancient habitats but were trophically linked via dinosaur dung. Over 130 fossil snails representing at least seven different taxa have been found on or within herbivorous dinosaur coprolites from the Upper Cretaceous Two Medicine Formation of Montana. The terrestrial snail Megomphix is the most common taxon, but three other terrestrial taxa ( Prograngerella , Hendersonia and Polygyrella ) and three aquatic snails ( Lioplacodes , ?Viviparus and a physid) also occur in coprolites. At least 46% of the shells in the faeces are whole or nearly so, indicating that most (if not all) of the snails were not ingested by dinosaurs, but were post-depositional visitors to the dung pats. The sizeable, moist and microbially enriched dinosaur faeces would have provided both food and roosting sites for the ancient snails, and the large number of snail-coprolite associations reflect recurring, opportunistic exploitation of dung.The terrestrial taxa in the coprolites suggest that this Late Cretaceous locality included sufficiently moist detrital or vegetative cover for snails when dinosaur dung was not present. The aquatic snails probably entered the faeces during flood events. Dinosaur dung would have provided an abundant but patchy influx of resources that was probably seasonally available in the ancient environment. ᮀ Coprolites, Cretaceous, dinosaurs, palaeoecology, snails/gastropods . Karen Chin[karen.chin@colorado.edu], Geological Sciences/Museum of Natural History,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.