Diagnoza

Adult sp elements of Siphonodella abundantly occurring in samplesDz-Z3 ard,Dz-46 (Fig. 16), which probably come from the same bed at opposite ends of the Dzikowiec quarry, usually show widened denticle tips of their blade (carina) in the region dorsal of the cusp. The tubercles covering the anterior half of the platform are then arranged in a fingerprint pattern that merges with the denticles of the blade. This is not so well visible, if present at all, in juvenile specimens and there is generally quite a wide variation in the platform ornamentation. All the elements of typical Siphonodella from these samples (except for the aberrant S. belkai sp. n.) show generally the same platform shape and none of them develops additional crests. It thus seems that the population is homogeneous and that the platform ornamentation variation is a matter of intraspecific variability. Less numerous elements of the same species encountered in higher parts of the section show similar ranges of the platform ornamentation.

The type population of this species comes from sample 436 of the locality Kronhofgraben in the Carnic Alps where it is the dominant species, only some specimens attributed to S. duplicate co-occurring with it (Schdnlaub 1969). This is the oldest bed containing Siphonodelld in this section. The sp elements of S. carinthiaca (Siphonodella cf. duplicara of Gedik, 1974) ue associated in sample 3623 from PldckenpaB in the Camic AJps with the type series of Piracognathus valdecavatus Gedik, 1969, which seems to represent the oz element of the same species. It co-occurs with other morphologies of sp elements in the more complete section of Kronhofgraben in the same region (Schtinlaub 1969). Below, it is proposed to restrict the meaning of the genus Siphonodella to species having oz elements of this type and sp elements with well developed ridges, other species transferring to Pinacognathus and, Dinodus.

In the Muhua section the oldest occurrence of oz elements resembling those attributed here to Siphonodella s.s. is 0.6 m above the base of the Carboniferous rocks (sample Mu-28), where sp elements are at best transitional from P. sulcatus to S. duplicata.

Porównanie

Autekologia

Występowanie geograficzne

Zasięg czasowy

Materiały muzealne

Literatura