Boudagher-Fadel et al. (1996):
Remarks: The aperture of this species is not
clear on the metatype figured here (Plate 2.6,
Fig. 15) but there is an indication of a sedimentfilled
intraumbilical arch with a thin rim. This
aperture and umbilicus are very similar to those
drawn by Gorbachik and Poroshina (1979, textfig.
1b), and are clearly conoglobigerine. The
sculpture of the wall surface consists of separate
pseudomuricae and short ridges formed by their
fusion; these ridges form broken cells, very close
to a reticulate, favose pattern, but as yet incomplete.
There can be no doubt that C. gulekhensis
is very closely ancestral to the earliest Favusella,
a genus which appears in the Hauterivian (or even
slightly earlier, in the Berriasian, according to
Wemli et al., 1995; our Plate 4.2).
The chamber shape, umbilical size and shape,
aperture and wall sculpture are very similar to
those of the contemporary C. caucasica (Gorbachik
and Poroshina). The principal difference
between the two taxa is the height of the spire
and very convex dorsal side of the test of
C. gulekhensis. It is possible that C. gulekhensis
is the microspheric form, and C. caucasica the
megalospheric partner of a dimorphic pair (as
suggested by Gorbachik and Poroshina, 1979,
p. 24), but the early whorls of each 'species' so
far imaged by SEM are obscure and this relationship
is not yet proven. |
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Gorbatchik,T.N. and Kuznetsova,K.I. (1983): Jurassic and Early Cretaceous planktonic foraminifera (Favusellidae). Stratigraphy and paleobiogeography . Zitteliana Vol. 10 p. 459-466
Gorbatchik,T.N. (1986): Jurassic and Early Cretaceous planktonic foraminifera of the south of the USSR [in Russian]. p. 239
Banner,F.T. and Desai,D. (1988): A review and revision of the Jurassic-Early Cretaceous Globigerinina, with special reference to the Aptian assemblages of Speeton (North Yorkshire, England) . J. micropalaeontol. Vol. 7(2) p. 143-185
Boudagher-Fadel,M.K.; Banner,F.T.; Bown,P.R..; Simmons,M.D. and Gorbatchik,T.N. (1995): Gorbachikella from the Hauterivian, Barremian-Aptian of Tunisia . Revue de Micropaléontologie Vol. 38 p. 179-193
Boudagher-Fadel,M.K.; Banner,F.T.; Gorbatchik,T.K.; Simmons,M.D. and Whittaker,J.E. (1996): Evolution in the Early Cretaceous planktonic foraminiferal genus Blefuscuiana . Jahrbuch für Geologie und Paläontologie, Abhandlungen Vol. 202 p. 243-258
Boudagher-Fadel,M.K.; Banner,F.T.; Whittaker,J.E. and Simmons,M.D. (1997): Early Evolutionary History of Planktonic Foraminifera. Vol. 1
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