Amphiplecta tripleura? Funakawa, 1995b

Plate 1, Figs. 5A – 7C.

Amphiplecta sp. Petrushevskaya, 1971, pl. 54, fig. 1.

Amphiplecta tripleura n. sp., Funakawa, 1995b, p. 18 –20, text fig. 5, pl. 1, figs. 1a–3b.

Remarks. The specimens observed in this study were observed in Middle and Late Miocene samples (~15.5—8.2 Ma), which is younger than the lower Miocene range given in Funakawa (1995b) ’s description. Our specimens differ from those illustrated by Funakawa in that they have a gradational decrease in pore size from the bottom to top of the cephalis. The apical spine is also less pronounced in our specimens, and the cephalis appears to be slightly wider. However, not enough specimens have been observed or figured in previous literature to fully understand the intraspecific variation or the true stratigraphic range of this taxon. It is possible that the specimens we observed are within the range of variation for Amphiplecta tripleura Funakawa, but it is also possible that they are a related Middle–Late Miocene form that will later be determined to be a distinct species.

Range. Middle– Late Miocene in the EEP. Lower limit not determined. See Table 1.