Zaphrentites sp.

El-Desouky, Heba, Herbig, Hans-Georg & Kora, Mahmoud, 2023, Kasimovian (late Pennsylvanian) cornute rugose corals from Egypt: taxonomy, facies and palaeogeography of a cool-water fauna from northern Gondwana, Swiss Journal of Palaeontology (32) 142 (1), pp. 1-39 : 24

Zaphrentites sp.

( Fig. 11C 1–C 4 ).

Material: One corallite (RAh 84), collected from the basal shales of the lower member of the Aheimer Formation. Three transverse thin-sections are available.

Description: External characters: Straight, conical, small (about 1.5 cm long) corallite. Calice is very deep, partly eroded. Septal furrows are marked on the external wall ( Fig. 11C 1 ).

Internal characters: Near the apex, in the earliest ontogenetic preserved stage, at diameter of 4 mm septa are 16 ( Fig. 11C 2 ). Major septa are sub-radial to pinnately arranged. They show a distinct white middle line. The cardinal fossula is well-developed with parallel sides and long, thin cardinal septum. Later with maturity, at a diameter of 6.4 mm there are 20 major septa ( Fig. 11C 3 ). These are radially arranged in the counter quadrants, curve towards the counter septum, and join to form a stereocolumn. The cardinal fossula has parallel sides with somewhat short cardinal septum. Alar fossulae are not developed. The uppermost mature section below calice floor ( Fig. 11C 4 ), displays 23 septa in 7.2 mm diameter. Septa are altered, and their ends are free, leaving a narrow free axial area. Cardinal septum is short. Minor septa are absent.

Discussion: Zaphrentites sp. and Zaphrentites cf. parallela (Carruthers, 1910) show almost no differences in the morphology of the earlier growth stages. Nevertheless, the studied Zaphrentites sp. shows n:d ratio in the last mature stage near the calice smaller than that of the Zaphrentites cf. parallela (Carruthers, 1910) ; (23: 7.2 vs. 26: 8.6; Fig. 12 ).

Figures

Fig. 11 A, B Zaphrentites cf. parallela (Carruthers,1910). A1–A3 Successive transverse sections in the specimen RAh (118), starting from the early immature stage with zaphrentoid arrangement of the septa in A1 to the last mature stage below the calice in A3. B1 External lateral view of the specimen RAh (109), showing strong longitudinal ribbing on the corallite wall. Positions of thin-sections indicated. B2–B4 Successive transverse sections represent the ontogenetic development, starting from the immature section in the apical part in B2 to the last mature section below the calice floor in B4. C Zaphrentites sp. C1 External view of the specimen RAh (84). C2–C4 Successive transverse sections; from the immature section in C2 to the last mature section below the calice floor in C4. Black dots indicate the positions of cardinal septum (below), counter septum (above) and the two alar septa

Fig. 1 Geological map of the eastern cliffs of the Northern Galala Plateau, modified after Abdallah and El Adindani (1965)

Fig. 4 Effects of diagenesis on some coral specimens: A Thin-section in the calice of the specimen RAh (44) shows a completely compressed calice filled with fossiliferous mud. B Thin-section below the calice of the Bothrophyllum okense (RAh 37) shows beginning of compression and breakage of septa. C Thin-section below the calice of the specimen RAh (79), shows completely broken and altered septa, probable outer dissepimentarium and axial structure, filled with ferruginous mud. D Thin-section of a completely compressed specimen RAh (200) shows high alteration,breakage and ferrugination of skeletal elements.E Thin-section in the early mature part of the Actinophrentis crassithecata n. sp.(RAh 11), shows ferrugination affects a large part of the interior skeleton. F Mature thin-section of Rotiphyllum exile (RAh 29), shows ferrugination and dolomitization of skeletal elements.G, H Thin-sections of mature part of the specimen (RAh 81) in G and the immature part of the specimen RAh (99) in H show extensive dolomitization and ferrugination of the internal skeletal elements

Fig. 2 A Lithostratigraphic succession of the Aheimer Formation studied along the eastern cliffs of the Northern Galala Plateau after Kora and Mansour (1992). B Enlargement of the mudstone dominated basal shale part of the lower member of the Aheimer Formation studied herein (see also Fig. 3A)

Fig. 3 Field aspects of the Aheimer Formation; A General view of the studied succession of the lower member exposed in a faulted block to the north of Porto Sukhna; the shales mudstones close to the base (rectangle) are interbedded with thin, hard dolomitic bands. B Close up view on of the lower fossiliferous shale mudstone beds of A. C, D Close-up view on of two rugose corals entombed in the shale mudstone beds.E Close-up view on of a rugose coral species with diagenetically compressed calyx. Note strong ferrugination of corallite and surrounding matrix within the fossiliferous shale. F Fossiliferous shales mudstone with thin bands of ferruginous dolomitic limestone and secondary evaporite veinlets; Cr = crinoidal stems. G Crinoid columnals (Cr) and rugose corals (RC) are embedded in the shale mudstone. H Close-up view on of a spiriferid valve shell within the shale (arrow). Diameter of coins in C–E, G: 25 mm

Fig. 12 Relation between number of major septa and coralla alar diameters for: A Lytvolasma paraaucta n. sp.,L aucta Fedorowski,1987, L. asymetrica Soshkina, 1925 described by Chwieduk (2013), L. canadense Fedorowski and Bamber, 2001 and the current studied L. cf. canadense Fedorowski and Bamber, 2001. B Monophyllum galalaensis n. sp. and M. parvum Fomichev, 1953. C Rotiphyllum exile de Groot, 1963. D Zaphrentites cf. parallela (Carruthers,1910) and Zaphrentites sp