The Paleontological Collections contain 244 Type Fossils: unique finds of enormous scientific value on which the recognition and description of a new species are based, thereby providing a reference for the specific attribution of finds made subsequently. The data accompanying their description also vaunt importance in dating the deposits in which the fossils were found.

The Type Fossil Collection offers specimens from a variety of taxonomic groups sampled in Italy since the end of the 19th century. The most widely represented include Trilobites, extinct marine arthropods found in Cambrian Period rocks in southwest Sardinia. Cephalopod mollusks, such as Ammonites from both the Triassic (Lombardy) and Jurassic (Apennine mountains in the Umbria-Marche regions); Gastropods collected from Triassic strata in the Gargano (Puglia); Eocene Period Echinoderms from Calabria and the Gargano; Lariosaurs, marine reptiles that are ancestors of dinosaurs; and Osteichthyes fish, from Triassic rock layers in Lombardy, are also present.

The classification of Type Fossils and the assignment of status to finds follow the International Code of Zoological Nomenclature. “Type” is the general term that indicates a fossilized species by a relevant and particular taxonomic status. “Holotype” is the specimen of a species that was studied, depicted, and published by the author who first gave it its scientific name. The locality of sampling of a species Holotype is referred to as the “Type Locality” and bears enormous chronostratigraphic importance. The “Paratype” is the specimen of the Type Series used by the author to describe the species. The “Syntype” is the specimen of a Type Series in which a Holotype is not designated. The “Lectotype” is the specimen later chosen as Holotype among the Syntypes. The “Plesiotype” is the specimen chosen by another author to complete the description of the species.