Helicosphaerella philippinensis

Helicosphaera philippinensis Müller, 1980

Small sub-quadrate helicolith having an asymmetrical blanket (Type II, Helicosphaerella recta type) blanket, truncated flange termination and a central area with an inverse conjunct bar.

Helicosphaerella philippinensis differs from Helicosphaerella obliqua (Bramlette & Wilcoxon, 1967) Aubry, Liu, de Vargas, & Probert in Aubry & Bord (2009) and Helicosphaerella perch-nielseniae (Haq, 1971) Aubry, Liu, de Vargas, & Probert in Aubry & Bord (2009) by being small and sub-quadrate. It is further distinguished from Helicosphaerella perch-nielseniae by having a distinct inverse bar in the central area.

Helicosphaerella philippinensis is differentiated from Helicosphaerella orientalis (Black, 1971c) Varol, n. comb. by having an inverse bar in the central area whilst the latter has a closed central area.

Aubry, M. -P., Bord, D., 2009. Reshuffling the cards in the photic zone at the Eocene/Oligocene boundary. In: Koeberl, C., Montanari, A. (eds), The Late Eocene Earth-Hothouse, Icehouse, and Impacts. Geological Society of America, Special Papers 452, 279-301.

Black, M., 1971c. The systematics of coccoliths in relation to the paleontological record. In: Funnell, B. M., Riedel, W. R. (eds), The Micropaleontology of the Oceans. Cambridge University Press, Cambridge pp. 611-624.

Bramlette, M. N., Wilcoxon, J. A., 1967. Middle Tertiary calcareous nannoplankton of the Cipero section, Trinidad, W.I. Tulane Studies in Geology and Paleontology 5, 93-131.

Haq, B. U., 1971. Paleogene calcareous nannoflora. Parts I-IV. Stockholm Contributions in Geology 25, 1-158.

Jafar, S. A., Martini, E., 1975, On the validity of the calcareous nannoplankton genus Helicosphaera. Senckenbergiana Lethaea 56, 381-397.

Müller, C., 1981. Beschreibung neuer Helicosphaera-Arten aus dem Miozän und Revision biostratigraphischer Reichweiten einiger neogener Nannoplankton-Arten. Senckenbergiana Lethaea 61, 427-435.