Diagnoza

M elements with relatively short and transversely arranged inner process; cusp of P₁ element only slightly longer than other denticles.

Derivation of name: Referring to extreme variability in shape of P₁ elements.

Porównanie

This is the geologically oldest species of the genus. Its unusual variability and small size suggests a paedomorphic origin and release of selection pressure on the apparatus morphology. Possibly the associated Mehlina kielcensis sp. n. is close to its ancestor, as suggested by similar M and P₁ elements but other elements of the apparatus are non-paedomorphic. Alternative to this ancestry is the relationship to Pandorinellina? vogelgnathoides but this would require a cryptic occurrence of the latter lineage during the K. triangularis Zone. As generally the francodinids show punctuated distribution, this is not unlikely.

In late populations of the species (e.g. J-58) most M elements show a rounded tip of the external process, which is typical for its successor, V. proclinatus.

Autekologia

Występowanie geograficzne

The K. triangularis Zone at Płucki and Jabłonna.

Zasięg czasowy

Materiały muzealne

748 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.