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Species Planomalina cheniourensis Sigal 1952 | ||||||
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Discussion / Comments: | ||||||
Caron (1985): It differs from P. buxtorfi in its more numerous chambers and absence of a peripheral keel in the last 3-4 chambers. Bellier & Moullade (2002): Our Leg 171B material permitted us to follow step by step the direct evolutionary linkage from Globigerinelloides algerianus (cf. PI. 3, fig. 1-3) to Planomalina cheniourensis, as suggested by Caron (1985), by the progressive acquisition of peripheral muricocarinae on the earhest, and then most, chambers in the last whorl. Conversely, BouDagher-Fadel et al. (1997) assume that P. cheniourensis "according to our phylogeny.., must have evolved from a macroperforate AlanlordeUa...". Our observations show that all Leg 171B specimens belonging to this species are microperforate, as well as those of their phylogenetic ancestor, G. algerianus. The type-species of the genus Planomalina (P. apsidostroba, junior synonym of the Vraconian P. buxtorfi) being macroperforate (cf. P1. 3, fig. 8-10), the taxon P. cheniourensis cannot belong to the same genus, according to the pre-eminent taxonomic ranking given by BouDagher- Fadel et al. (1997) using their microstructural criterion. Planomalina cheniourensis cannot belong to Globigerinelloides as well, since this genus is restricted to globular-chambered forms, devoid of muricocarinae. The taxonomic decisions which are needed at the generic level will be detailed in a further paper (Moullade et al., submitted). Boudagher-Fadel et al. (1997): Remarks: This species differs from P. buxtor- (Gandolfi) by its more numerous chambers (twelve chambers in the last whorl) and absence of peripheral muricocarina on the last three chambers. According to our phylogeny (Figure 5.2), this species must have evolved from a macroperforate Alanlordella (which, as we have seen, can have muricocarina on the earliest chambers of the last whorl), but presumably not from A. bentonensis, from which the P. buxtor- lineage is thought to have derived (see further discussion under A. praebuxtor- (Wonders), pp. 214, 246). Although we have retained this species in the fully muricocarinate Planomalina, as we have said before (p. 211), the transition between these genera is essentially gradual and arbitrary. Nevertheless this phylogeny is at variance with that suggested by Caron (1985) who would derive P. cheniourensis from Globigerinelloides algerianus Cushman and Ten Dam by progressive acquisition of the peripheral keel. |
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Systematics: | ||||||
5 Classis Foraminifera Familia Planomalinidae Genus Planomalina Species Planomalina cheniourensis 22 Superfamilia Globigerinaceae Familia Planomalinidae Genus Planomalina Species Planomalina cheniourensis |
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Synonym list: | ||||||
Caron (1985): 1952 Planulina cheniourensis Sigal. - Sigal : p.21 text-fig 17
1985 Planomalina cheniourensis Sigal. - Caron : 66, 67 figs 29.3-4
Bellier & Moullade (2002): 1952 Planulina cheniourensis Sigal. - Sigal : p.20 fig. 17
1966 Planomalina cheniourensis Sigal. - Moullade : 130-131 fig. 3
1984 Planomalina cheniourensis Sigal. - Leckie : p.598 pl. 4; fig. 1-4
1985 Planomalina cheniourensis Sigal. - Caron : p.65 fig. 29.3-4
1997 Planomalina cheniourensis Sigal. - Boudagher-Fadel et al. : p.215 pl. 12.6; fig. 10-13
2002 "Planomalina" cheniourensis Sigal. - Bellier & Moullade : p.25 pl. 3; fig. 4-7
Boudagher-Fadel et al. (1997): 1952 Planulina cheniourensis Sigal. - Sigal : p.21 text-fig. 17
1985 Planomalina cheniourensis Sigal. - Caron : p.65 fig. 29.3-4
1997 Planomalina cheniourensis Sigal. - Boudagher-Fadel et al. : p.227 pl. 12.6; fig. 10-13; Figure: 12.1
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Was used in synonym list of: | ||||||
References: | ||||||
Sigal,J. (1952): Moullade,M. (1966): Leckie,M.R. (1984): Caron,M. (1985): Boudagher-Fadel,M.K.; Banner,F.T. and Whittaker,J.E. (1997): Boudagher-Fadel,M.K.; Banner,F.T.; Whittaker,J.E. and Simmons,M.D. (1997): Bellier,J.P. and Moullade,M. (2002): |
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Anonymous: Unedited TaxonConcept data | ||||||
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