Acta Palaeontologica Polonica

Thomasaria vs. Pyramidalia conundrum in Devonian brachiopod systematics solved: An argument to formalize epitypification under the ICZN

Adam T. Halamski and Andrzej Baliński

Acta Palaeontologica Polonica 64 (2), 2019: 399-408 doi:https://doi.org/10.4202/app.00603.2019

Pyramidalia is a brachiopod genus with Spirifera simplex as the type species. Imprecise diagnosis and misidentification of the material studied in the original description resulted in a plethora of interpretations (a valid genus belonging either to the order Spiriferida or to the Spiriferinida; synonym of the spiriferide Thomasaria; synonym of Squamulariina or Cyrtinaella, both spiriferinides). To address this problem we designated the specimen GSM 6915 from Wolborough quarry near Newton Abbot (Devon, England; Givetian) as the lectotype of Spirifera simplex. We examined microstructure and internal characters of a topotypic specimen and found out that Spirifera simplex has an impunctate shell and is thus a spiriferide, not a spiriferinide. No significant differences in morphology or internal characters of Thomasaria and Pyramidalia can be found, so the latter is interpreted as a junior subjective synonym of the former. The procedure used in the present analysis is equivalent to the epitypification provided for in the ICN; formalisation of a similar procedure under the ICZN is recommended.

Key words: Brachiopoda, Pyramidalia, Thomasaria, epitypification, ICZN, Devonian, UK, England.

Adam T. Halamski [ath@twarda.pan.pl] and Andrzej Baliński [balinski@twarda.pan.pl], Institute of Paleobiology, Polish Academy of Sciences, ul. Twarda 51/55, 00-818 Warszawa, Poland.


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