Upper Jurassic record of Polyphylloseris (Egypt, Northern Sinai)
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ORIGINAL PAPER
Upper Jurassic record of Polyphylloseris (Egypt, Northern Sinai) Mohammed Gameil & Franz T. Fürsich & Mohammed H. Mandurah
Received: 16 April 2012 / Accepted: 10 September 2012 # Saudi Society for Geosciences 2012
Abstract Genus Polyphylloseris is a scleractinian colonial coral that has been established by d’Orbigny (1849) from the Neocomian of Yonne, France. The genus is characterized by having elevated domal calices that are mammillar or craterlike in shape and with porous confluent septa. Columella is absent or rudimentary, and the lower surface of the corallum is covered with a thick and wrinkled holotheca. Specimens having the above-mentioned characteristics have been collected from the Upper Jurassic Arousiah Member of the Masajid Formation (Callovian–Oxfordian) of Gebel Maghara, Northern Sinai, Egypt. They are characterized by having a cupolate colonial form and porous pennulate septa which reach 40–50 in number. Based on these characters and other characters such as density of septa, height, and width of mammillar calices, the studied material is attributed to a new species named Polyphylloseris magharensis. The new species is a first undoubted record of Polyphylloseris in the Jurassic. Previously recorded undoubted ages of the genus are Early and Late Cretaceous. The fewer number of septa and the smaller-sized and closer mammillar calices allow differentiation of the species from other species such as Polyphylloseris icaunensis d’Orbigny and Polyphylloseris convexa d’Orbigny. Keywords Corals . Polyphylloseris . Jurassic . Egypt
M. Gameil (*) : M. H. Mandurah Department of Petroleum Geology and Sedimentology, King Abdulaziz University, Jeddah, Saudi Arabia e-mail: [email protected] F. T. Fürsich GeoZentrum Nordbayern, Universität Erlangen, Erlangen, Germany e-mail: [email protected]
Introduction During our investigation of Jurassic specimens from Gebel Maghara, Northern Sinai, Egypt (Fig. 1), the present authors observed some cupolate or hemispherical colonies composed of elevated domal calices that are regularly distributed on its upper surface. These calices carry calicular pits on their summits; they are circular and deep. Comparing the collected specimens to the previously described scleractinian corals, it appears that they belong to a new species of genus Polyphylloseris. The genus Polyphylloseris was first described by Fromentel (1857) from the Lower Cretaceous (Neocomian) of France. The specimens were previously identified by d’Orbigny (1849) from the same locality under Polyphyllastrea based on two species Polyphylloseris icaunensis and Polyphylloseris convexa. Fromentel (1857) observed the presence of numerous synapticulae joining the porous septa; this lead him to change the generic name to Polyphylloseris. Morycowa (1971, p. 118–120) gave a detailed description of P. convexa and treated its taxonomic affinity. The genus is generally recorded in the Lower Cretaceous (Hauterivian–Albian) of many regions such as France (d’Orbigny 1849; Alloiteau 1952, 1957), Swit
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