<i>Neopycnodonte </i>Stenzel, 1971 (Bivalvia: Ostreida: Pycnodonteinae) – an interesting grypheid fossil oyster from the Croatian Natural History Museum collections

Bivalves of the genus Neopycnodonte Stenzel, 1971 (Ostreida: Gryphaeidae) are known as common bioconstructors from the mesophotic marine environments of the Cenozoic era. Along with mussels, they are among the first taxa to colonize natural and artificial hard substrates, but they live somewhat deeper, being most common between 50 and 150 m.More than eighty specimens of fossil Neopycnodonte from the Neogene deposits of Mt. Medvednica, the Samoborsko gorje Hills, the Glinsko Pokuplje area and Siena (Italy) are housed in the Croatian Natural History Museum (CNHM) under the names: Ostrea cochlear Poli, 1795, Picnodonta cochlear (Poli, 1795) and Picnodonta ( Ostrea ) cochlear (Poli, 1795) var. navicularis (Brocchi, 1814). The presence of the Pycnodonteinae subfamily was also recorded from several areas in Croatia during the preparation of the Basic Geological Maps. Like many other oysters, pycnodonteins are highly variable in shape and there have been some doubts concerning their taxonomy. The authors support one of the previously suggested taxonomical schemes (Freneix, 1975), assigning the fossil specimens from CNHM to the species Neopycnodonte navicularis (Brocchi, 1814), which is considered a direct ancestor of the recent N. cochlear ( Poli, 1795).