Opis

Despite the wide geographic distrib ution of the ge nus, whic h is especially well
represented in co llec tio ns from the Table Head Formation of Newfoundland (STOUGE 1984) its
relationships remain obsc ure . Ornamen tat ion and shape of juve ni le elemen ts are suggestive of a
relationship with cooccurring Lenodu s variabilis but there are also some morphologically more
primitive conodonts similar to Polonodus, for instance ea rly species of the Pygodus lineage (DZIK
1983) attributed to Polonodu s by STOUGE and BAGNOLI ( 1988). Only a single element type has been
identified with certainty, although the occurrence of add itional type s was sugges ted by BERGSTROM
( 1983). LOFGREN ( 1990) proposed a complete apparatus reconstruction with a Lenodlls-like filtratory
basket.
The platform elements of Polonodus have a very deep basal cavity and bifurcating processes ornamented with transverse rows of tubercles of variable size. At early ontogenetic stages they are cruciform in occlusal view, later in its ontogeny quite complex shapes may develop.

Type species: Ambalodus clivosus VIIRA, 1974.

Synonimy

Zasięg czasowy

Literatura

Dzik, J. 1994a Conodonts of the Mójcza Limestone. In: J. Dzik, E. Olempska, & A. Pisera. Ordovician carbonate platform of the Holy Cross Mountains. Palaeontologia Polonica 53, 43-128.