Hypolophodon sylvestris was an early Eocene myliobatiform ray belonging to the stingray lineage. Its flattened disc shaped body and swimming by undulation of the enlarged pectoral fins are inferred from its batoid relationships, because the species is usually known from isolated hard parts rather than complete skeletons. The low pavement like dentition is direct evidence of a feeding system very different from the piercing teeth of contemporary sharks.

The broad low crowns were suited to gripping and processing food taken on or close to the seabed. A diet including small molluscs, crustaceans and other benthic invertebrates is therefore a reasonable functional inference, although direct gut contents are not known. The species was probably a demersal ray that foraged over soft or mixed substrates rather than an open water pursuit predator.

Fossils consist mainly of tiny isolated teeth and characteristic dermal denticles or tubercles. Tooth shape varies across the dental pavement, so median and lateral positions should not be expected to have identical proportions. Published teeth are only a few millimetres across, making well preserved crown margins and roots particularly important.