The genera Lepidorbitoides and Orbitcoides: evolution and stratigraphic significance in some Anatolian basins
Küçük Resim Yok
Tarih
1999
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
WILEY-BLACKWELL
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Early ontogenetic morphologic features previously recognized as evolutionary parameters in Lepidorbitoides and Orbitoides have been tested in several flysch successions of Anatolia. Increase in embryo size (Li + ii), number of epi-embryonic chambers (E) and organization of embryonal chamber arrangement from 'quadrilocular' to 'bilocular' and multilocular in Orbitoides, increase in deuteroconch size (D), in deuteroconch-protoconch ratio (D/P) and in number of adauxiliary chambers (Ad) in Lepidorbitoides have been recognized as the main evolutionary trends, thus allowing the correlation of these features with time. The different developmental stages in Lepidorbitoides, i.e. L. pembergeri, L. campaniensis, L. bisambergensis, L. minor, L. socialis, and in Orbitoides, i.e. O. media, O. megaloformis, O. gruenbachensis, O. apiculata and O. gensacicus, have been described and illustrated based on the biometry of the populations. The values observed in some horizons, however, may not reflect the true phylogenetic stage of the orbitoidal taxa, especially in the species of Orbitoides, which usually show a wide variation of evolutionary parameters in the same population. A correlation scheme of phylogenetic development in Lepidorbitoides and Orbitoides with the planktonic foraminiferal zones is proposed. Lepidorbitoides populations with highly asymmetric 'quadriserial' nepionts occurring stratigraphically below the symmetric ones in Early Maastrichtian are thought to deserve a particular taxonomic status. In Orbitoides, a new embryonal chamber morphology previously undescribed from horizontal sections has been discovered. Copyright (C) 1999 John Wiley & Sons, Ltd.
Açıklama
Anahtar Kelimeler
Lepidorbitoides, Orbitoides, early ontogeny, biometry, biostratigraphy, plankton-benthos correlation, Late Cretaceous, Anatolia, Turkey
Kaynak
GEOLOGICAL JOURNAL
WoS Q Değeri
Q3
Scopus Q Değeri
Cilt
34
Sayı
3
