Pandorinellina bituberculata (Dzik, 2006) from the P. jugosus Zone at Jabłonna in the Holy Cross Mountains.

Pandorinellina bituberculata - P₁ element.

Diagnoza

Robust blade of P₁ elements, mature elements tend to develop large tubercle on each side of the widened basal cone, which is subcircular in outline and restricted to the mid-length of the blade.

Porównanie

The species is another successor of P. vulgaris representing the opposite to the tendency in P. fragilis towards a robust appearance of all elements. Juveniles of the ancestor and successor are indinstinguishable and can be attributed to its species only on the basis of co-occurrence with adult specimens and geological age. Because of this, the species affiliation of the late Famennian populations of Pandorinellina known exclusively from immature specimens remains tentative. This is especially troublesome with the Kowala section, where acid treatment of limestone samples produces mostly juvenile specimens of Pandorinellina, whereas washing of the intercalating clay (e.g., Ko-131) supplies robust mature specimens. From unknown reason the population dynamics of the species depended on whether limy mud or fine clay was deposited. Although the taxonomy of the P. vulgaris-group is inconveniently difficult to apply, the distinctions between species seems rather well substantiated.

Autekologia

Występowanie geograficzne

Jabłonna, Ostrówka, Kowala, and Dzikowiec.

Zasięg czasowy

L. styriacus to P. jugosus Zones. 

Materiały muzealne

ZPAL: 49 specimens.

Literatura

Dzik, J. 2006. The Famennian "Golden Age" of conodonts and ammonoids in the Polish part of the Variscan sea. Palaeontologia Polonica 63, 1-359.