The palaeontological character of the Lower Cretaceous (Valanginian) hydrothermal vent filling of the Mecsek Mts, Hungary

Abstract

The fauna of the Valanginian shallow-marine hydrothermal vent site of the Mecsek Mts (South Hungary) is unique.
In Europe this is the only shallow-marine vent site from the Mesozoic, which gives a special importance to the site.
Furthermore, its uniqueness is more pronounced by the mixing of typical vent-related taxa and other non-vent related
normal shallow-marine taxa. The prevailing elements of the fauna are the large-sized brachiopods dominated by
Lacunosella hoheneggeri and Nucleata veronica. Beside the brachiopods, the rich and diverse microcoprolite ichnofauna
refers to a vivid and rich crustacean fauna. The ichnofauna contains eleven species of Favreina, Parafavreina, Helicerina
and Palaxius genera. Together, these count as the most diverse microcoprolite ichnofauna of the Mesozoic. These typical,
vent-related elements are mixed up with the normal shallow marine fossils, such as cephalopods (Nautiloidea gen. et sp.
ind., Lytoceras, Phylloceras sp.), gastropods (?Pleurotomaria sp.) and (in great quantities) echinoid spines (Cidaris,
Balanocidaris, Pseudocidaris); the latter are not generally considered as vent-related taxa.