Alanlordella bentonensis Morrow 1934 (TaxonConcept

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Species Alanlordella bentonensis Morrow 1934

Diagnosis / Definition:

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.

Discussion / Comments:

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.

Systematics:

22
Superfamilia Globigerinaceae
  Familia Planomalinidae
   Genus Alanlordella
    Species Alanlordella bentonensis

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

Was used in synonym list of:

Blowiella caseyi Bolli et al. 1957

References:

Morrow,A.L. (1934):
Foraminifera and Ostracoda from the Upper Cretaceous of Kansas . Journal of Paleontology Vol. 8 p. 186â€“205

Bolli,H.M.; Loeblich,A.R. and Tappan,H. (1957):
The Planktonic foraminiferal families Hantkeninidae, Orbulinidae, Globorotaliidae, and Globotruncanidae . U.S. National Museum Bull. Vol. 215 p. 3-50

Low,D. (1964):
Redescription of Anomalina eaglefordensis Moreman . Contributions from the Cushman Foundation for Foraminiferal Research Vol. 15 p. 122, 123

Salaj,J. and Samuel,O.. (1966):
Foraminiferen der Westkalpaten-Kreide (Slowakei) . Geologický Ústav Dionýza Stúra, Bratislava p. 292

Pessagno,E.A. (1967):
Upper Cretaceous planktonic foraminifera from the West Coastal Plain . Palaeontographia Americana Vol. 5 p. 259-441

Wonders,A.A.H. (1975):
Cretaceous planktonic foraminifera of the Planomalina buxtorfi group from El Burrueco, southern Spain . Koninklijke Nederlandse Akademie van Wetenschappen, Amsterdam, Proceedings, Series B Vol. 78 p. 83-93

Masters,B.A. (1977):
Mesozoic Planktonic Foraminifera.
In: Oceanic Micropalaeontology Eds: Ramsay, A.T.S. p. 301-731

Carter,D.J.. and Hart,M.B.. (1977):
Aspects of mid-Cretaceous stratigraphical micropalaeontology . Bulletin of the British Museum (Natural History) (Geology) Vol. 29 p. 1-135

Salaj,J. (1980):
Microbiostratigrayhie du Crétacé et du Paléogéne de la Tunisie septentrionale et orientale (hypostratotypes tunisiens) . Geologický Ústav Dionýza Stúra, Bratislava p. 238

Hart,M.B..; Bailey,H.W..; Fletcher,B..; Price,R.. and Sweicicki,A.. (1981):
Cretaceous.
In: Stratigraphical Atlas of Fossil Foraminifera Eds: Jenkins, D.G.Murray, J.W. p. 149-227

Ben Haj Ali,N.. (1987):
Étude biostratigraphique du Crétacé (Aptien á Cénomanien) de la Région du Teboursouk (Tunisie septentrionale) sur la base des foraminiféres planctoniques . Notes du Service Géologique Tunisie Vol. 54 p. 75-105

Boudagher-Fadel,M.K. (1995):
The planktonic foraminifera of the Early Cretaceous of Tunisia compared to those of western and central Tethys . Paleopelagos Vol. 5 p. 137-160

Boudagher-Fadel,M.K.; Banner,F.T.; Whittaker,J.E. and Simmons,M.D. (1997):
Early Evolutionary History of Planktonic Foraminifera. Vol. 1

Anonymous: Unedited TaxonConcept data

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