Nannotax3 - ntax_main - Discoaster micros

Citation: Discoaster micros (Theodoridis 1984) de Kaenel & Villa 1996

Basionym: Eu-discoaster micros * Theodoridis 1984

Taxonomic discussion: Discoaster transitus Peleo-Alampay et al. (1998) was considered a synonym of D. micros by Raffi et al. (1998) and this opino was previously followed on Nannotax. However, de Kaenel et al. (2017) note that D. micros has a large central area whereas D. transitus does not, so we follow them in separating the species.

Distinguishing features:
Parent taxon (D. musicus group):
This taxon: Small discoaster with short arms; bifurcations almost touching and thicker than the arms

Geological Range:
Last occurrence (top): within NN9 zone (9.53-10.55Ma, top in Tortonian stage). Data source: de Kaenel et al. 2017
First occurrence (base): within NN6 zone (11.90-13.53Ma, base in Serravallian stage). Data source: de Kaenel et al. 2017

References:

de Kaenel, E. & Villa, G. (1996). Oligocene-Miocene calcareous nannofossil biostratigraphy and paleoeecology from the Iberian Abyssal Plain. Proceedings of the Ocean Drilling Program, Scientific Results. 149: 79-145. gs O

de Kaenel, E., Bergen, J. A., Browning, E., Blair, S. A. & Boesiger, T. M. (2017). Uppermost Oligocene to Middle Miocene Discoaster and Catinaster taxonomy and stratigraphy in the circum North Atlantic Basin: Gulf of Mexico and ODP Leg 154. Journal of Nannoplankton Research. 37(2-3): 215-244. gs O

Okada, H. & Bukry, D. (1980). Supplementary modification and introduction of code numbers to the low-latitude coccolith biostratigraphic zonation (Bukry, 1973; 1975). Marine Micropaleontology. 5: 321-325. gs

Peleo-Alampay, A., Bukry, D., Liu, L. & Young, J. R. (1998). Late Miocene calcareous nannofossil genus Catinaster: taxonomy, evolution and magnetobiostratigraphy. Journal of Micropalaeontology. 17(1): 71-85. gs

Raffi, I., Backman, J. & Rio, D. (1998). Evolutionary trends of tropical calcareous nannofossils in the late Neogene. Marine Micropaleontology. 35(1): 17-41. gs

Theodoridis, S. (1984). Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin. 32: 1-271. gs O

variants - intergrading morphotypes with slightly different ranges (time control age-window is: 0-800Ma)
				Discoaster catillomicros Prominent central stem and well-developed central area depressions
				Discoaster stellimicros Prominent central stem
				Discoaster arneyi A thick species of the D. micros group with long rays, nearly flat bifurcations and a featureless central area.
				Discoaster premicros A thick species of the D. micros group with short rays, flat bifurcations and a featureless central area

Discoaster micros

References:

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