Brachyuran decapods (including five new species and one new genus) from Jurassic (Oxfordian-Kimmeridgian) coral reef limestones from Dobrogea, Romania

摘要

Analysis of the fossil decapod faunas in coral reefs from localities at Topalu and Piatra in Central Dobrogea, Romania, yielded four new species, Goniodromites narinosus, Verrucarcinus cutifrontis, Laeviprosopon lazarae, Lecythocaris stoicai, belonging to Homolodromioidea ALCOCK, 1899, and one new genus and species, Concavolateris barbulescuae, assigned to Glaessneropsoidea PATRULIUS, 1959. Comparison of the abundance and diversity of decapod faunas from these Jurassic coral reefs with those from sponge-algal reefs in the same geographic area and of the same age (middle Oxfordian) has led to some interesting paleoecological differences. The coral reef environ-ments yielded 124 specimens of decapods, of which 54 were brachyurans. The brachyuran were represented by six families in seven genera and ten species, including the new taxa. The sponge reef environments yielded 22 specimens that represented only three families with four genera and five species. These two different types of environments share only one genus in common, Goniodromites, and no species. The nearly complete taxonomic difference between the environments suggests that the environments selected for different adaptations, leading to niche partitioning within and between habitats. The higher abundance and diversity in the coral environments may reflect a higher number of niches available for decapods, shallower water depth, higher oxygen content and/or difference in energy levels in the two environments, making coral reefs a more suitable environment for decapods.