The new foraminiferal genus &amp;lt;i&amp;gt;Ammogloborotaloides&amp;lt;/i&amp;gt; n. gen. and subfamily Ammogloborotaloidinae n. subfam. from the Neogene of Venezuela: an example of isomorphism between agglutinated and planktonic Foraminifera

Michael A Kaminski,Jime Contreras

doi:10.1144/0262-821x10-025

Abstract

Abstract. We report the occurrence of two new species of the new agglutinated foraminiferal genus Ammogloborotaloides in the Miocene of western Venezuela. These two taxa have been assigned informal names and have been known to the petroleum industry in Venezuela for many years, but have never been described. A. truncatulinoidiformis n. sp. is the type species and the second species, A. sp. 16, is left in open nomenclature. The two species of Ammogloborotaloides are strongly isomorphic with the planktonic foraminiferal species Globorotalia truncatulinoides and Globorotalia crassaformis, and illustrate the possible evolutionary connections between agglutinated benthics and the planktonic foraminifera.

Highlights

As part of a programme to revise the taxonomy of benthic foraminifera in the collections of the Venezuelan State Petroleum Company (PDVSA), we examined numerous numbered slides labelled ‘Trochammina’ in the type collections housed in the Geological Laboratory in La Conception, Venezuela
Among the numerous unnamed species of trochamminids present in the collections, we discovered striking examples of species that we first provisionally assigned to the genus Ammogloborotalia Zheng, 2001
The collection of foraminiferal type slides dates from the 1950s, and the numbered species designations have been in general use in the Venezuelan petroleum industry for many years

Summary

Introduction

As part of a programme to revise the taxonomy of benthic foraminifera in the collections of the Venezuelan State Petroleum Company (PDVSA), we examined numerous numbered slides labelled ‘Trochammina’ in the type collections housed in the Geological Laboratory in La Conception, Venezuela. Among the numerous unnamed species of trochamminids present in the collections, we discovered striking examples of species that we first provisionally assigned to the genus Ammogloborotalia Zheng, 2001. Upon closer examination of the apertural characteristics, the Neogene taxa were found to differ from Cretaceous and Recent Ammogloborotalia, which necessitated the establishment of a new genus. These taxa from the Miocene of the Falcon Basin and from Lake Maracaibo are strongly isomorphic with late Neogene species of Globorotalia. The purpose of this paper is to provide descriptions of these new taxa, and point out their strong isomorphism with well-known modern species of Globorotalia

Objectives

Methods

Conclusion