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Notes on Three Cretaceous Foraminiferal Genera, Asterorbis, Orbitocrclina and Pseudorbitella


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1 Tohoku University, Sendai, Japan
     

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Critical reviews on Asterorbis rooki Vaughan and Cole, A? aguayoi Palmer, A? macei Palmer, A? cubensis Palmer, A? havantnsis Palmer, Orbitocyclina nortoni Vaughan, O. minima (Douvillfe), O. cardtnascnsis (Galloway), O. rutteni (Thiadens), O. rutteni var. armata (Thiadens), O. macgillaviyi (Thiadens), O. palmerae (Thiadens), O. planasi (Rutten) and O. floridensis (Cole) were carried out.

All the species of Asterorbis are quite the same in their juvenile features. No regular series is found in the arrangement of the nepionic chambers in this genus excepting for the principal auxiliary chambers. All the species of Asterorbis ever proposed art suggested to be assembled into a single species as to be synonymous with Asterorbis rooki. Furthermore, Asterorbis rooki may be canaliferous and would be referred to a family independent from the Lepidorbitoididae and cannot be assigned to the Pseudorbitoid- idae which is characterized by the sulcoperculine juvenarium although this family is canaliferous.

Orbitocyclina nortoni, O. mimina, O. cardtnascnsis, O. rutteni, O. rutteni var. armata and O. palmerae are plausible to be united into a single species, Orbitocyclina minima. O. planasi may possibly be distinguished from O. minima in having the thicker roofs and floors of lateral chambers. O. floridensis is distinguishable from 0. minima in having thicker pillars.

The occurrence of Pseudorbitella americana Hanzawa is reported from Cuba.


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  • Notes on Three Cretaceous Foraminiferal Genera, Asterorbis, Orbitocrclina and Pseudorbitella

Abstract Views: 199  |  PDF Views: 2

Authors

Shoshiro Hanzawa
Tohoku University, Sendai, Japan

Abstract


Critical reviews on Asterorbis rooki Vaughan and Cole, A? aguayoi Palmer, A? macei Palmer, A? cubensis Palmer, A? havantnsis Palmer, Orbitocyclina nortoni Vaughan, O. minima (Douvillfe), O. cardtnascnsis (Galloway), O. rutteni (Thiadens), O. rutteni var. armata (Thiadens), O. macgillaviyi (Thiadens), O. palmerae (Thiadens), O. planasi (Rutten) and O. floridensis (Cole) were carried out.

All the species of Asterorbis are quite the same in their juvenile features. No regular series is found in the arrangement of the nepionic chambers in this genus excepting for the principal auxiliary chambers. All the species of Asterorbis ever proposed art suggested to be assembled into a single species as to be synonymous with Asterorbis rooki. Furthermore, Asterorbis rooki may be canaliferous and would be referred to a family independent from the Lepidorbitoididae and cannot be assigned to the Pseudorbitoid- idae which is characterized by the sulcoperculine juvenarium although this family is canaliferous.

Orbitocyclina nortoni, O. mimina, O. cardtnascnsis, O. rutteni, O. rutteni var. armata and O. palmerae are plausible to be united into a single species, Orbitocyclina minima. O. planasi may possibly be distinguished from O. minima in having the thicker roofs and floors of lateral chambers. O. floridensis is distinguishable from 0. minima in having thicker pillars.

The occurrence of Pseudorbitella americana Hanzawa is reported from Cuba.