outside Ornithopoda was retained by Paul Sereno in 1991, it was considered a possibly valid taxon based on its prominent anterior and posteriormost denticles. Galton revised his classification of the taxon in 1994, considering it only referrable to Ornithopoda, and not closely related to Echinodon. Trimucrodon was then compared favourable by Galton in 1996 to the also Portuguese taxon Taveirosaurus, previously considered a pachycephalosaur. With the later reclassifications of Taveirosaurus as more similar to nodosaurids, Trimucrodon was identified by José Ruiz-Omeñaca in 1999 to either be a member of Heterodontosauridae alongside Echinodon, or a member of Nodosauridae related to Taveirosaurus. While the identity as a possible heterodontosaurid was upheld by Ruiz-Omeñaca and José Canudo in 2004, in the same year Weishampel, Witmer and colleague David B. Norman followed their 1990 opinion on Trimucrodon, placing it as a dubious ornithischian, though they noted that further study could potentially support the validity of the taxon. Trimucrodon was found at the top of a cliff south of Porto Dinheiro, in the lower beds of the Lournihã Formation alongside a tooth referred to the ornithischian Hypsilophodon, teeth from rhamphorhynchoid pterosaurs, the crocodylomorphs Lusitanisuchus and Goniopholis, the choristoderan Cteniogenys, the lizard Saurillus, and over 800 teeth of various groups of mammals. Other deposits from the Amoreira–Porto Novo Member at Porto Dinheiro have contained material from the sauropods Zby and Dinheirosaurus, the theropods Lourinhanosaurus, Torvosaurus and Ceratosaurus, ornithischian remains from the stegosaur Miragaia and an intermediate member of Iguanodontia, a possible pleurosternid turtle, and scales from the fish Lepidotes. References Ornithischian genera Kimmeridgian life Late Jurassic dinosaurs of Europe Jurassic Portugal Fossils of Portugal Fossil taxa described in 1975 Nomina dubia