Somalina praestefaninii n . sp . , a new Species of Large Foraminifera from the dammam Formation ( Lutetian ) of gebel hafit , united arab Emirates

The stratigraphic succession exposed in the Gebel Hafit area of the United Arab Emirates (Fig. 1) ranges from Eocene to Miocene in age (HUnTinG, 1979; CHERiF & El DEEb, 1984; HAMDAn & bAHR, 1992; AnAn et al., 1992; AnAn, 1996). basically, the lower Eocene is represented by a relatively thin sequence of limestones, with marl intercalations in its upper part (Rus Formation), while the Middle and Upper Eocene are represented by thick sequences of limestones with marl and shale intercalations (Dammam Formation). both formations have a wide aerial extent in the Emirates, Qatar, and Saudi Arabia (boUkHARy & Al SHARHAn, 1998).


IntroductIon
The stratigraphic succession exposed in the Gebel Hafit area of the United Arab Emirates (Fig. 1) ranges from Eocene to Miocene in age (HUnTinG, 1979;CHERiF & El DEEb, 1984;HAMDAn & bAHR, 1992;AnAn et al., 1992;AnAn, 1996).basically, the lower Eocene is represented by a relatively thin sequence of limestones, with marl intercalations in its upper part (Rus Formation), while the Middle and Upper Eocene are represented by thick sequences of limestones with marl and shale intercalations (Dammam Formation).both formations have a wide aerial extent in the Emirates, Qatar, and Saudi Arabia (boUkHARy & Al SHAR-HAn, 1998).

StratIgraphy
The stratigraphic section measured along Wadi Tarabat at the core of the Hafit domal structure (Fig. 2) is represented by two formations, an older Rus Formation and younger Wadi Al nahayan Formation.

rus Formation, Late ypresian
The Rus Formation (THRAllS & HASSon, 1956) is composed of 40 m of white, medium to coarse grained, thickly bedded limestone, with gray chert nodules in the lower part and marl intercalations in the upper part.Two members are distinguished within the Rus Formation, the Sulaimi and Doha Members.

Sulaimi Member
The Sulaimi Member (boUkHARy & Al SHAR-HAn, 1998) is exposed in the lower part of Gebel Hafit and is composed of about 25 m of thick-bedded white or cream-weathering medium to coarse-grained limestone.The upper part is composed of thinly-bedded cream to light-brown argillaceous limestone.The base of this unit is not exposed.based on foraminifera Aca rinina bullbrooki bolli, Globigerina turgida FinlAy, and Morozovella aragonensis (nUTTAll), the unit is assigned to the level of the late Early Eocene.The middle part is either barren or with poorly preserved foraminifera, such as Acarinina bullbrooki bolli, A. pentacamerata SUbboTinA, Globigerina turgida FinlAy, Morozovella aragonensis (nUTTAll), and is characterized by a nummulitic horizon with Nummu lites subramondi DE lA HARpE, besides Orbitolites, Alveolina and algal nummulitic limestones.This unit is correlated with the middle part of the Hili Member of the Rus Formation according to HAMDAn & bAHR (1992).The upper part is conformable with the overlying Doha Member.

Doha Member
The Doha Member (boUkHARy & Al SHARHAn, 1998) is defined from the lower Eocene outcrops of Qatar. it is unconformably overlain by the Dammam Formation (as defined from Qatar).The unit is composed of well-bedded grey to cream, fine-mediumgrained nodular limestones with chert nodules and marl intercalations (15 m).Marls are rich in planktonic foraminifera, including Subbotina inaequispira (SUbboTinA) doensis SUbboTinA, A. spinuloinflata bAnDy, and Pseudohastigerina micra (ColE).Some horizons are rich in large foraminifera, e.g.Nummulites bassiounii boUkHARy & blonDEAU.According to the foraminiferal associations this unit is dated as late Early Eocene (boUkHARy & blonDEAU, 1991).The unit is correlated with the upper part of the Hili Member of HAMDAn & bAHR (1992).

Wadi al nahayan Formation, Early/Middle Lutetian
The The unit is exposed on both limbs of the Hafit anticline with a variable thickness (3-6 m).These conglomerates represent a sudden shallow shift in sedimentation related to an uplift of the Arabia platform during the Early to Middle lutetian.Also, this uplift seems to be responsible for the absence of the p10-p12 interval on the western side of Qatar (lutetian lacuna, boUkHARy & Al SHARHAn, 1998).

Stratigraphic remarks
The studied section is correlated with other countries (Qatar, Saudi Arabia and Egypt) to delineate important stratigraphic levels related to Somalina occurrences (Fig. 3).Consequently, Somalina praestefaninii n. sp.recorded from the basal part of the Dammam Fomation (lutetian) is the ancestral form of Somalina stefaninii SilvESTRi, a characteristic species for the bartonian.Also, the sequence of Somalina praestefaninii n. sp.could be correlated with the stratigraphic lacuna (between the Rus and Dammam formations) in Qatar, bahrain, kuwait, Saudi Arabia and Egypt (boU-kHARy & Al SHARHAn, 1998;boUkHARy et al., 2006).Accordingly, the Mibazara Member corresponds to the black and red tuffs with Nummulites perplexus of Malo, italy (SCHAUb, 1981), where both of the two units are characterized by conglomeratic facies.1978 (pl. 3, figs. 1-3; pl. 4, figs. 1-3; pl. 41) has a diameter of 3.7 mm and a thickness of 0.4 mm for the forma A with a plurilocular apparatus in vertical section, with internal dimension of 1200x500 μm.
For the forma b, the diameter is 33 mm for a thickness of 3 mm.The lateral layers, with vacuoles of variable dimensions, are similar to those of the type species.The new species mainly differs from the other species by its shape and size.it is associated with Alveolina aff.muni eri HoTTinGER and Alveolina sp.only the form A of S. khorassanica RAHAGHi is known (RAHAGHi, 1978, p. 41-42, pl. 2, fig. 4).The main characteristic of this form is the reduction and even the absence of the lateral layers.its diameter is 0.7 mm and can reach 8 mm.The embryonic apparatus has an internal dimension of 300x400 μm.
Somalina praestefaninii n. sp. is a new large foraminiferal species separated from the Mibazara member.it is believed that Soma lina praestefaninii n. sp. is the ancestral form of Somalina stefaninii SilvESTRi as it is smaller and has a more simple protoconch.Here, it is believed that the taxon Somalina (lutetian) could possibly be derived from Opertorbitolites nUTTAll, 1925 (the taxon characteristic for the ypresian).
(boUkHARy et al., 2006)on(HAMDAn &  bAHR, 1992)forms the basal part of the El Dammam Group.it is composed of tan to light brown limestone with shale interbeds.The Dammam Group (720 m thick) is separated into four formations from base to top: Wadi Al nahayan, Ain Al Faydah, Maziad, and Senaiya Formations.The Wadi Al nahayan Formation is separated from the underlying Rus Formation by a 6 m thick conglomeratic layer, the Mibazara Member(boUkHARy et al., 2006).This unit is composed of highly compacted and unoriented limestones pebbles and cobbles.The clasts are highly cemented by a fine reddish matrix of marly nummulitic carbonates rich in large benthic foraminifera, including Assilina spira abrardi SCHAUb, Somalina praestefaninii n. sp., and Nummulites perplexus SCHAUb, similar to the basal lutetian assemblage of italy(SCHAUb, 1981, p. 132).
RAHAGHi (1978) the ledian of Somalia (in the lower part of the Carcar iv) with Linderina buranen sis nUTTAll & bRiGHTon, Pentellina sp., rotalids and miliolids.RAHAGHi (1978)described Somalina stefaninii SilvESTRi from the Middle Eocene of iran (region of Shiraz), the diameter of these specimens is 8 mm and their thickness is 1.6 mm.The embryonic apparatus has an internal dimension (in vertical section) of 600x400 μm.This species is associated with Pseudo lituolinella reicheli MARiE, Lituonella sp., Dictyoconus sp., Praerhapydionina sp., and Orbitolites complanatus lAMARCk.Also, this author described two new species: Somalina gigantea RAHAGHi and S. khorassani ca RAHAGHi, both from the Middle Eocene.S. gigan tea RAHAGHi (SCHMiDT & SHinDEll, 2003)ence (Ypresian, TA-2): Umm Er Radhuma-Rus/Esna Thebes-Minia Formations.This sequence is represented by a succession of shales and limestones and laid down under a major Tethyan transgression.The sequence ended with a major regression resulting in the absence of Early This sequence is represented by a succession of marls and limestones and was laid down under a major Tethyan regression accompanied by the Middle Eocene hyperthermal event(SCHMiDT & SHinDEll, 2003).This sequence is only recorded from the United Arab Emirates and Egypt.A tectonic trigger for this sequence is obvious from the lower Egyptian basins (Mokattam).