Catalog - Sigalia

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Sigalia

Type species: Guembelina deflaensis Sigal, 1952

Test compressed, biserial, rarely tending to add more than one chamber per series (row) in very late stages; wall structure calcareous, perforate; sutures limbate, covered by prominent rows of raised beads, giving the apertural end of each chamber a 'truncated' character; aperture arched, half-moon-shaped, in basal position at the inner margin of the chamber ('guembelinid'). Family Guembelinidae.

Relationships and remarks. - Sigalia differs from Guembelina by its raised and beaded sutures, by its rare tendency to add more than one chamber per row, and by the absence of a spiral stage; from Ventilabrella by its well-developed, long biserial stage with only a rare tendency to build more than one (maximum two) chambers in a series (row) in very late stages, and by its raised and beaded sutures of all chambers; from Pseudoguembelina by the lack of secondary apertures; from Bronnimannella by the shape of its chambers, by the raised and beaded sutures, and by the lack of the characteristic ornamentation; from Gublerina by the lack of the "intercalated, hollow space" (espace vide intercalaire); from Bolivinella, which resembles Sigalia, by the apertural characters, in Sigalia and by the latter's tendency to build more than one chamber per row in late stages.

As far as Ventilabrella decoratissima de Klasz is concerned, it might belong partly to Sigalia deflaensis (Sigal) [Guembelina deflaensis, 1952]. De Klasz himself states (1953, p. 228) that mostly biserial forms occur. On the other hand, he figured as holotype a specimen which shows a long biserial stage with beaded sutures, but followed already by a Ventilabrella stage (although short) with ' spreading' chambers, lacking the beads on the sutures, which appear depressed. The figured holotype of Ventilabrella decoratissima must be regarded, considering de Klasz' statement, as not representative of the species. It represents probably a very evolved form, transitional between Sigalia and Ventilabrella, originating in this writer's opinion from strata of late Santonian age. It should be noted that Sigal (1955, pp. 157-160) states that the Ventilabrella plexus appears later than the Guembelina plexus of Guembelina (Guembelina, Ventilabrella) deflaensis Sigal. It must also be emphasized that this writer has not observed hitherto true Ventilabrellae in the eastern Tethys region before the late Santonian. This is true also for Israel and for North Africa. Through the kindness of J. Sigal this writer was able to examine Santonian material from North Africa containing Sigalia deflaensis at the Institut Francais du Petrole, Rueil-Malmaison, during a recent trip to Europe, as well as at the Geological Survey of Israel, where material from North Africa is deposited. Observations on this material show that most of the specimens of Sigalia deflaensis are biserial throughout, the beads on the sutures being present in all chambers, while only extremely rare specimens from late Santonian strata show more than one chamber (maximum two) per row in very late stages and this not more than once (compare Sigal's figures, 1952) ; and that of Bettenstaedt and Wicher, 1955, World Petrol. Congr., 4th, Proc., sec. 1/D, fig. 2l. 11 lt seems therefore that Sigalia is the ancestor of at least certain types of Venttlabrella. Thus, St~alta deflaensts is the ancestor of Ventilabrella decoratissima, which in turn is probably the ancestor of Ventilabrella alpina de Klasz, an assumption supported by their stratigraphic distribution. The origin of Sigalia is unknown. It is probably an offshoot of a Guembelina, being intermediate between Guembelina and Ventilabrella, or at least certain species of the latter.

Occurrence. - Sigalia is known up to now from the uppermost Coniacian? and especially from the Santonian of the eastern Tethys region (Sigal, 1952; Sigal, 1955; de Klasz, 1953; Bettenstaedt and Wicher, 1955; and Reiss, 1955, Israel, Geol. Survey, Bull. (Israel, Res. , Coun. , Bull. , vol. 21). Only one species, Sigalia deflaensis (Sigall, has been hitherto described. In Israel Sigalia deflaensis is an excellent marker for the Santonian (Globotruncana concavata zone, compare Sigal, 1955, p. 158l."

References:

de Klasz, I. (1953a). Einige neue oder wenig bekannte Foraminiferen aus der helvetischen Oberkreide der bayerischen Alpen, südlich Traunstein (Oberbayern). Geologica Bavarica. 17: 223-244. gs

Reiss, Z. (1957a). Notes on foraminifera from Israel. 1. Remarks on Truncorotalia aragonesis caucasica (Glaessner). 2. Loxostomoides, a new late Cretaceous and early Tertiary genus of foraminifera. 3. Sigalia, a new genus of foraminifera. Bulletin Research Council of Israel (Reprinted In Israel Geological Survey Bulletin). 6B: 239-244. gs

Sigal, J. (1952). Apercu stratigraphique sur la micropaleontologie du Cretace. XIX Congr. géol. internat., Algers, Monographies Regionales. 1(26): 3-43. gs

Sigal, J. (1955). Notes micropaleontologiques nord-africaines. Du Cenomanien au Santonien. Zones et limites en facies pelagique. Compte Rendu Sommaire des Séances de la Société Géologique de France. 7-8: 157-160. gs

Missing or ambiguous references: Bettenstaedt & Wicher 1955;

			Sigalia bejaouensis Salaj&Maamouri 1971
			Sigalia carpatica Salaj&Samuel 1963 = Sigalia carpatica
			Sigalia deflaensis rugocostata Nederbragt 1991 = Sigalia rugocostata
			Sigalia incipiens Georgescu 2010
			Sigalia proliferans Georgescu, M.D. 2010

CATALOG OF ORIGINAL DESCRIPTIONS: Sigalia Reiss 1957

Sigalia

References:

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