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Species Alanlordella bentonensis Morrow 1934 | ||||||
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| Diagnosis / Definition: | ||||||
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Boudagher-Fadel et al. (1997): Diagnosis: Test planispiral, about 210-360 µm at its maximum diameter, biumbilicate; six to seven chambers in the last whorl, globular, almost as high as broad, increasing rapidly in size; sutures radial and depressed; aperture interiomarginal, equatorial, symmetrical, extending laterally into each umbilicus for half of the last whorl, furnished with portici; wall smooth, not muricate, but macroperforate in the early part of the last whorl; the macroperforations are visible only in the early part of the whorl, but the later chambers retain the microperforations of this species' ancestors. |
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| Discussion / Comments: | ||||||
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Boudagher-Fadel et al. (1997): Remarks: In rare specimens, later in the Early Albian, the antepenultimate chamber develops a tubulospine (Plate 12.1, Fig 9) like Schackoina. Anomalina eaglefordensis Moreman (1927), considered by Loeblich and Tappan (1961) to be a senior synonym of this species, was subsequently confirmed as a benthonic species (Low, 1964; Pessagno, 1967) and all the planktonic individuals referred to it were placed by them in Globigerinelloides caseyi (Bolli, Loeblich and Tappan), a species first described from the Albian Gault Clay of England. However, after examination of topotype material, Carter and Hart (1977, p. 28) rejected the name caseyi using G. bentonensis for the Late Albian and Cenomanian forms found in the British succession. A suite of specimens from Tunisia and from the Gault Clay Formation, Arlesey brick pit, Cambridgeshire (the type locality of G. caseyi) are illustrated in Plate 12.3, Figs 1-9, Plate 12.4, Figs 1-9) and these have been matched with Bolli, Loeblich and Tappan's original illustrations of caseyi, and with those of 'G' bentonensis (Morrow). All are considered conspecific. Moreover, the Tunisian and the English specimens are identical in that the last formed chambers are still microperforate (like the ancestral Blowiella) but the early chambers of the last whorl have become macroperforate. This species is transitional from microperforate Blowiella to the macroperforate Alanlordella. In the latter genus muricae begin on the early chambers of the last whorl and are absent on the later chambers. This evolution is clearly protogenetic in that the morphological features of the adult ancestors are recapitulated in the latest stages of life while the newly evolved characters (macroperforations and muricae) appear in the early stages of ontogeny during evolution. They later extend to all growth stages, and with the acquisition of muricae become true Alanlordella. On the other hand, the umbilicus of A. bentonensis is wider than in typical Blowiella but it has not reached the great width of typical Globigerinelloides. Carter and Hart (1977) and Hart et al. (1981) were correct in considering that A. bentonensis arose from Blowiella, but the species of immediate ancestry has yet to be determined. |
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| Systematics: | ||||||
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22 Superfamilia Globigerinaceae Familia Planomalinidae Genus Alanlordella Species Alanlordella bentonensis |
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| Synonym list: | ||||||
| Boudagher-Fadel et al. (1997): 1934 Alanlordella bentonensis Morrow. - Morrow : p.201 pl. 30; fig. 4a, b
1957 Planomalina caseyi Bolli et al.. - Bolli et al. : p.24 pl. 1; fig. 4, 5
1964 Globigerinelloides caseyi Bolli et al.. - Low : 122, 123
1966 Planomalina (Globigerinelloides) caseyi Bolli et al.. - Salaj & Samuel : p.161 pl. 6, fig. 1a, b
1967 Globigerinelloides bentonensis Morrow. - Pessagno : p.275 pl. 76; fig. 10, 11
1967 Globigerinelloides caseyi Bolli et al.. - Pessagno : p.276 pl. 46; fig. 2-5
1975 Globigerinelloides nomen emend. caseyi Bolli et al.. - Wonders : p. 88, 89 pl. 1, fig. 3a, b;
text-fig. 4, fig. 1a, b
1977 Globigerinelloides bentonensis Morrow. - Masters : p.404 pl. 10; fig. 2, 3
1977 Globigerinelloides cushmani Tappan. - Masters : pl.10; fig. 1
1977 Globigerinelloides bentonensis Morrow. - Carter & Hart : p. 27, 28 pl. 1, fig. 11;
pl. 2, fig. 19, 20
1980 Planomalina (Globigerinelloides) bentonensis Morrow. - Salaj : fig. 11, 13, 21-23
1981 Globigerinelloides bentonensis Morrow. - Hart et al. : p.198 pl. 7.13; fig. 7-9
1987 Globigerinelloides bentonensis Morrow. - Ben Haj Ali : p.86
1987 Globigerinelloides eaglefordensis Moreman. - Ben Haj Ali : pl. 4; fig. 14, 15
1995 "Blowiella" bentonensis Morrow. - Boudagher-Fadel : p.145 pl. 3, fig. 1-9;
pl. 4, fig. 6
1997 Alanlordella bentonensis Morrow. - Boudagher-Fadel et al. : p. 221, 223 pl. 12.3, fig. 1-9;
pl. 12.4, fig. 1-9;
Figure: 12.1
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| Was used in synonym list of: | ||||||
| References: | ||||||
Morrow,A.L. (1934): Bolli,H.M.; Loeblich,A.R. and Tappan,H. (1957): Low,D. (1964): Salaj,J. and Samuel,O.. (1966): Pessagno,E.A. (1967): Wonders,A.A.H. (1975): Masters,B.A. (1977): Carter,D.J.. and Hart,M.B.. (1977): Salaj,J. (1980): Hart,M.B..; Bailey,H.W..; Fletcher,B..; Price,R.. and Sweicicki,A.. (1981): Ben Haj Ali,N.. (1987): Boudagher-Fadel,M.K. (1995): Boudagher-Fadel,M.K.; Banner,F.T.; Whittaker,J.E. and Simmons,M.D. (1997): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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