Abstract

Necdetina (type species N. taurica n. sp.) is described here as a new fusulinoidean genus with a replaced or recrystallized wall from the Middle Permian (Capitanian) of Turkey. In addition to its distinctive wall structure, which was probably originally keriothecal and composed of aragonite or high-Mg calcite, the genus is characterized by an ovate shell with rounded to acute poles and axially elongated, biserially enrolled chambers. Chomata are absent, but inconsistently developed parachomata-like structures are present in the test where biserially enrolled chambers overlap. Circular foramina alternate in two rows at the bases of the apertural face and septa.

Phylogenetic analysis indicates that Necdetina belongs in the clade of staffellid fusulinoideans, a group whose walls are invariably altered. Among the staffellids, Necdetina is allied with other genera in which the coiling axis is elongated to produce a spherical, oval or fusiform test. In this subclade, Necdetina is further united with Thailandina and Neothailandina in possessing parachomata and having well-organized foramina along the antetheca and septa. Necdetina is the only known staffellid, indeed the only known fusulinoidean, with biserial chambers.

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