Arabian Journal of Geosciences (2018) 11:484 https://doi.org/10.1007/s12517-018-3840-8 ORIGINAL PAPER A new organ-species dasycladalean green alga from Darbandikhan, Kurdistan, Iraq Ioan I. Bucur 1 & Kamal Haji Karim 2 & Hyam Daoud 2 & Bruno Granier 3,4 & Polla Azad Khanaqa 5 Received: 28 March 2018 / Accepted: 16 August 2018 # Saudi Society for Geosciences 2018 Abstract Algal-rich limestones have been identified during fieldwork at Zawali (Shameran) Mountain, Darbandikhan, Iraq. The algae occur within an 8-m thick interval of fine-grained gray limestone in the lower part of the Khurmala Formation (Upper PaleoceneLower Eocene). In this area, the Khurmala Formation is 170 m thick and consists mostly of poorly fossiliferous dolomitic lagoonal limestone. Thin intervals contain gastropods, pelecypods, foraminifers (e.g., miliolids, soritids, rotaliids, and rare nummulitids), and calcareous green algae. One of these levels consists almost exclusively of fertile ampullae of a bornetellacean dasycladalean alga. Here we define it a new organ-species: Frederica kurdistanensis nov. sp. Keywords Calcareous algae . Dasycladales . New species . Iraq Introduction Fossils considered to be reproductive organs of dasycladalean algae have been described in the literature under various names. Most of them have been assigned to Acicularia Archiac 1843. Originally, it was considered that this genus is extant [Acicularia schenckii (Möbius) Solms-Laubach 1895]. However, Génot (1987) pointed out that Acicularia is present only in fossil record. Isolated parts of dasycladalean reproductive organs have also been assigned to the genera Terquemella Munier-Chalmas ex Morellet and Morellet 1913, Carpenterella (Munier-Chalmas ex Morellet and Morellet 1922) Génot 1980, Parkerella (Munier-Chalmas ex Morellet and Morellet 1922) Génot 1987, Frederica Barta-Calmus 1965, Russoella Barattolo 1984, Sandalia Dieni et al. 1985, * Ioan I. Bucur ioan.bucur@ubbcluj.ro Kamal Haji Karim karimgeology@yahoo.com Hyam Daoud hyam.daoud@univsul.edu.iq Bruno Granier bgranier@univ-brest.fr; bgranier@ku.edu Polla Azad Khanaqa drpolla@hotmail.com and Ioanella Granier and Berthou 2002. From Paleogene sedimentary deposits, a total of 18 Acicularia, 23 Terquemella, and 3 Frederica organ-species have been described (Deloffre and Granier 1992; Bucur 1999; Barattolo 2002). Two horizons with fossils that can be assigned to dasycladalean calcareous algae reproductive organs have been identified in Palaeogene carbonates in the Darbandikhan region of Iraq. Here we describe specimens from one of these levels, which we assign to a new organ-species. Location and geological setting The studied section is located 3 km southeast of Shameran village (about 40 km southeast of Sulaimani 1 Department of Geology and Center for Integrated Geological Studies, Babeş-Bolyai University, M. Kogălniceanu str. 1, 400084 Cluj-Napoca, Romania 2 Department of Geology, University of Sulaimani, Sulaimanyia City, Kurdistan Region, Iraq 3 Dépt. STU, Fac. Sci. Tech., UBO, 6 avenue Le Gorgeu, CS 93837, F-29238 Brest, France 4 Department of Ecology and Evolutionary Biology, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA 5 Kurdistan Institution for Strategic Studies and Scientific Research (KISSR) and University of Human Development, Qirga, Sulaimani, KRG, Iraq 484 Page 2 of 10 Fig. 1 Location of the Darbandikhan area, and the studied section. a Google image of the area around the Zawali sampled section; b location of the studied section on a tectonic map (after Buday 1980); c Arab J Geosci (2018) 11:484 tectonic sketch of the northwest Zagros belt with location of the Darbandikhan area (modified from Sissakian 2000) Arab J Geosci (2018) 11:484 Page 3 of 10 484 Fig. 2 Field view of the outcrop of the Khurmala Formation (Darbandikhan area) and location of the algae-bearing interval City) in the high Zagros Mountains of Kurdistan, northeastern Iraq. The section is located along the south side of the road connecting Darbandikhan to villages near the border of Iran (coordinates: 35° 06′ 44.21″ N 45° 49′ 25.97″). The Zawali Mountain, which is part of the large Shameran Mountain, is about 1000 m high and is situated in the eastern part of Darbandikhan Lake (Figs. 1 and 2). This area belongs to the High Folded Zone (Buday 1980) in the Western Zagros Fold-Thrust belt. The Zawali Mountain is part of the northwestern side of Shameran Anticline. The Khurmala Formation crops out along the northeastern limb of this anticline (Fig. 1). Several authors have contributed to the geological study of the region: Buday and Jassim (1987), Lawa (2004), Jassim and Goff (2006), Ibrahim (2009), Aqrawi et al. (2010), Al-Qayim et al. (2012), Lawa et al. (2013), and Karim et al. (2016). thin intervals of fossiliferous limestone in its upper part. The fossiliferous intervals contain foraminifers (miliolids, soritids, rotaliids, rare nummulitids), calcareous green algae, gastropods, and pelecypods (Fig. 4). The dasycladalean algae can be observed by hand lens along two intervals about 8 m in thickness in the lower part of section (Figs. 4 and 5). The first documentation of the Khurmala Formation in this area was by Karim et al. (2008). Previously, these deposits were attributed to the Sinjar Formation (van Bellen et al. 1959; Buday 1980; Jassim and Goff 2006; Sissakian 2000; Maala 2008). These authors suggested that the Khurmala Formation represents a lateral (lagoonal) facies of the Sinjar Formation, the later one developing a reefal facies and containing nummulites indicating a Late Paleocene-Early Eocene age. The succession of the Khurmala Formation along the Zawali section is presented in Fig. 3. Stratigraphy Gercus Formation The Khurmala Formation overlies the Kolosh Formation and is overlain by the Gercus Formation (Fig. 3). The boundaries between these formations are conformable (gradational) passing through transitional intervals. The Kolosh Formation is composed of dark and light gray sandstone, marl, and thin beds of conglomerate and, in the studied area, is 370 m thick. Its thickness in its type locality, according to van Bellen et al. (1959), is 700 m. In the area studied, the Gercus Formation has variable thickness. Its maximum thickness occurs near Darbandikhan Town (Mirade village), where it is more than 200 m thick. It is composed of red claystone, sandstone, and lenses of conglomerate. Its boundary with Khurmala Formation is gradational. Khurmala Formation A recent exposure of this formation occurs along the southern side of the road on the north side of Zawali Mountain (Fig. 3). The formation is about 175 m thick and consists mainly of poorly fossiliferous, pale-gray dolomitic limestone with relatively Twelve samples, Za2 to Za13, selected according to the change of lithology, were taken from the Khurmala Formation (Fig. 3). Sample Za4 contains abundant specimens of fertile ampullae belonging to dasycladalean green algae (Fig. 4). From this sample we made 10 thin sections Material and method 484 Page 4 of 10 Arab J Geosci (2018) 11:484 Fig. 3 Lithostratigraphic column of the studied section on Zawali (Shameran) Mountain for petrographic study. More than 500 specimens have been studied. The thin sections labeled ZA4-1 to Za4a10 are deposited in the Paleontological Museum of the Geology Department, Babeş-Bolyai University, ClujNapoca, under the numbers 24068–24077. Paleontological description Order Dasycladales Pascher 1931 Family Bornetellaceae Granier and Bucur in Granier et al. 2013 Organ-genus Frederica Barta-Calmus 1965 Arab J Geosci (2018) 11:484 Page 5 of 10 484 Dimensions Ampulla length = 0.75 to 0.97 mm; ampulla thickness = 0.37 to 0.53 mm; diameter of the cystic cavities = 0.060–0.080 mm; number of cystic cavities in longitudinal section = 22–24; number of cystic cavities in transverse section = 9–11; total number of cystic cavities approx. 200–250. Comparisons. Discussion on generic assignment Fig. 4 Stereo-microscope image of a broken surface of the rock containing Frederica kurdistanensis nov. sp. Khurmala Formation, sample Za4 (within the interval 58–66 m) Generotype Frederica villiersi Barta-Calmus 1965 Frederica kurdistanensis Bucur, Karim and Granier, nov. sp. Figs. 4, 5, 6a–d,7, 8 2018 Dasycladacean green algae—Karim et al., p. 43, Fig. 7 Origin of the name: from the Kurdistan region of Iraq Holotype: specimen in Fig. 7d, thin section Irak-1, inventory number 24068 Paratypes: specimens in Fig. 7a–c, e–i, thin sections Irak-1 to Irak-5 (24068 to 24072) Type locality: Zawali Mountain, Darbandikhan area, Iraqi Kurdistan Region Type level: Upper Paleocene-lowermost Eocene, lower part of Khurmala Formation Diagnose Cylindroid, slightly narrowed in the middle part, calcareous bodies representing pluricystic fertile ampullae of bornetellacean algae. The original cyst-containing cavities are located juxtaposed at the corpuscle periphery. They are separated by a thin wall that also divides these cavities from the inner area of the corpuscles. Each cavity opens outwardly through a funnel-like opening, the openings (or pores) being regularly alternatively displayed (in quincunx). The inner parts of the ampullae are primarily empty. Description The pluricystic fertile ampullae have a cylindroid shape (Fig. 7a–e) with a conic-elongate (Fig. 7f–h) or short conic-pyriform (Fig. 7i–l) aspect in some oblique sections. The cystic cavities are located in a micritic calcareous wall at the peripheries of the ampullae, in a regular alternating pattern that is clearly visible in tangential sections (Fig. 7m– r). The cross sections (Fig. 7s–v) are rounded and illustrate the same juxtaposed arrangement of the cystic cavities. These cavities are ovoid (Fig. 8) and separated by, originally aragonitic, thin calcareous walls (Fig. 8a, arrow). Their outer opening is funnel-shaped (Fig. 8b, arrow). Based on these features, our studied specimens could belong to either of the genera Acicularia, Terquemella, or Frederica. Acicularia d’Archiac 1843 was defined as characterized by flat or sharp claviform ampullae that are narrow at their proximal end and wider at their distal end. The distal extremity may be straight, lobate, or sharp. The ampullae are usually grouped in disk-shaped regions, or may be isolated. The cysts are located at the ampullae’s periphery, while the axial area is fully calcified—except in the case of a few species (Génot 1987). Terquemella Munier-Chalmas ex Morellet and Morellet 1913 occurs as spherical, ovoidal, lens- or disk-shaped corpuscles. Overall, or only on one side, they show pores leading to a small round cavity carved at the periphery of the sporangia (gametophores), where the spore (cyst) was located (Morellet and Morellet 1922). In most cases, the cystic cavities are irregularly distributed at the periphery of the ampullae; the inner area is fully calcified (Génot 1987). Frederica Barta-Calmus 1965 presents spherical, empty, narrow, and fragile corpuscles with a regularly perforated surface. The pores are displayed in quincunx located in the center of alveoli. The regular, ovoid cavities that must have hosted the spores do not communicate with the central cavity: a thin wall separates each alveolus from the neighboring one (BartaCalmus 1965). Based on these characteristics of the three genera, the specimens collected from Iraq most resemble the genus Frederica. In Eocene deposits from the Paris Basin, Génot (1978) identified Frederica villiersi specimens of varied shape (spherical, ovoidal, or pyriform). Typically, their inner part is empty, or filled by poorly consolidated calcite cement. This feature was used to propose an emendation of their generic assignment. According to Génot (1978), the main difference between Frederica and Terquemella is in the peripheral cavities. In Frederica, they are always juxtaposed so that the external pores are regularly located at the surface of the corpuscle (see also Génot 2009; Génot and Granier 2011). In contrast, in Terquemella the cystic display is much more irregular. As a rule, the corpuscles and the peripheral cavities are larger in Frederica. Also, Frederica shows an empty central cavity which occasionally is filled by a loose network of aragonite needles, while in Terquemella the central cavity is always calcified. 484 Page 6 of 10 Arab J Geosci (2018) 11:484 Fig. 5 a–h Microfacies of the dolomitic limestone with Frederica kurdistanensis nov. sp. showing various sections of the relatively abundant algae in a dolomitized limestone matrix; fragments of corallinacean red algae are very rarely present (h). a Thin section Za4-Irak-8; b thin section Za4-Irak-1; c thin section Za4-Irak-2; d thin section Za4Irak-5; e, f thin section Za4-Irak9; g, h thin section Za4-Irak-10. Scale bar is 1 mm except for d = 0.5 mm Dieni et al. (1985) described two new species from the Paleocene of Sardinia which they assigned to Frederica, F. arbustiformis, and F. coniconvexa. These authors did not support the emendation proposed by Génot for the genus Frederica (because it appeared in an unpublished thesis). Dieni et al. (1985) provided the following emended diagnosis of the genus: BPluricystate fertile ampullae variable in shape (spherical, ovoidal, pear-shaped, conical). Peripheral part of calcareous bodies with spherical-ovoidal pores in regular alternate arrangement and with funnel-like openings. Central part completely or partially calcified.^ This emendation practically cancels most of the previously stated differences between Terquemella and Frederica. The funnel-like aspect of the cystic cavity openings is not only a typical feature for organ-genus Frederica. This shape can also be observed in species of Terquemella [e.g., Terquemella asteroidea (Bakalova) 1975 (originally Acicularia asterroidea), Aptian]. However, from a morphological Arab J Geosci (2018) 11:484 Page 7 of 10 484 Fig. 6 a–c Longitudinal, oblique, transverse, and tangential sections of Frederica kurdistanensis n. sp. d Detail with recrystalized corallinacean red algae associated with Frederica kurdistanensis nov. sp. e Poorly preserved textulariid agglutinated foraminifer associated with the dasycladalean algae. f Detail from the dolomitized matrix. a Thin section Za4-Irak-4; b, f thin section Za4-Irak-5; c thin section Za4-Irak-6; d, e thin section Za4Irak-7. Scale bar is 0.5 mm (a–d), and 0.25 mm (e, f) perspective, the fertile ampullae assigned to the organ-genus Terquemella show the same variability in shape: spherical, ovoidal, conic, and also discoidal—but always with a compact, well-calcified corpuscular inner area. Moreover, numerous specimens of Jurassic and Lower Cretaceous age assigned to the organ-genus Acicularia, and very likely all of those assigned only to the organ-genus Terquemella (see Bucur et al. 2008) show a regular and closely packed display of the cysts (e.g., Bouroullec and Deloffre 1970, pl. 2, Figs. 2, 4; Conrad and Peybernès 1974, pl. 3, Figs. 1, 2; Simmons and Al-Thour 1994, pl. 4.6 Figs. 6, 7; Pop and Bucur 2001, Figs. 13–17). Based on these features, as well as because the specimens of organ-genus Terquemella are usually smaller in size than those assigned to Frederica (Génot 1978), we consider that both Frederica arbustiformis and Frederica coniconvexa are more likely to be species of the organ-genus Terquemella then of the organ-genus Frederica. As mentioned above, the specimens described here from the Paleogene of Iraq show the typical features of the organgenus Frederica: location of cysts in an external calcified area, 484 Page 8 of 10 Fig. 7 Frederica kurdistanensis nov. sp. a–e Longitudinal sections through cylindroid specimens, most of which have a slight narrowing in the middle part; a thin section Za-4-Irak-4; b thin section Za4-Irak-2; c thin section Za4-Irak-2; d holotype, thin section Za4-Irak-1, inventory number 24068. a–c Paratypes, thin sections Za4-Irak-1 to Za4-Irak-5 (24068 to 24072); e thin section Za4-Irak-1. f–h Elongated-oblique sections. f Thin section Za4-Irak-1; g thin section Za4-Irak-3; h thin section Arab J Geosci (2018) 11:484 Za4-Irak-5. i–l Short-oblique sections. i–k Thin section Za4-Irak-2; l thin section Za4-Irak-1; m–r tangential sections showing the close juxtaposition of the cyst chambers arranged in quincunx. m, n Thin section Za4Irak 1; o, p thin section Za4-Irak-2; q thin section Za4-Irak-3; r thin section Za4-Irak-6. s–v Specimens showing the circular shape of the transverse sections. s, t Thin section Za4-Irak-1; u thin section Za4Irak-2; v thin section Za4-Irak-9. Scale bar is 0.25 mm Arab J Geosci (2018) 11:484 Page 9 of 10 484 Fig. 8 Close up view of two specimens showing the ovoid shape of the cyst cavities; the thin wall separating this cavity from the surrounding micritic wall (arrow in a), as well as the funnellike opening of the cavities (arrow in b) are also visible their regular display, ampullae of relatively large size. The cystic chambers are separated by a calcareous wall that separates both the cysts one from another, and from the inner side of the calcareous hosting wall. Frederica kurdistanensis Bucur et al. nov. sp. differs from Frederica villiersi especially with regard to its dominantly cylindroid external morphology, slightly narrowed in the median part. Microfacies and paleontological association Frederica kurdistanensis Bucur et al. nov. sp. has been identified in an intensely dolomitized limestone (Fig. 6f) where it represents the main fossil (Fig. 5). On a surface of 2 cm2, we have counted between 150 and 200 specimens as longitudinal, transversal, or oblique sections (Fig. 5; Fig. 6a–c). The Frederica remains are associated with rare and poorly preserved fragments of coralline algae (Fig. 6d), and rare foraminifers (Fig. 6e). They were probably deposited in a shallowwater, somewhat restricted habitat (restricted lagoon). Conclusions Frederica kurdistanensis Bucur, Karim and Granier, nov. sp. is described from Paleogene carbonate deposits of the Darbandikhan region, Iraqi Kurdistan. These belong to the Khurmala Formation, a 175-m thick succession of limestones, dolomitic limestones, and poorly fossiliferous dolomites. At its base, about 8-m of dolomitic limestone contain numerous fertile pluricystate ampullae showing characteristic morphological features. Their detailed description allowed us to distinguish a new species. Frederica kurdistanensis Bucur et al. nov. sp. differs from F. villiersi—the type species of this organ-genus, by the dominant cylindroid morphology of the ampullae that are slightly narrowed in the median area. Acknowledgements We thank Phil Salvador and Robert Riding for English corrections, as well as the reviewers Marc Conrad, and an anonymous reviewer whose remarks and corrections helped to improve the manuscript. References Al-Qayim B, Omer A, Koyi H (2012) Tectonostratigraphic overview of the Zagros Suture Zone, Kurdistan region, northeast Iraq. GeoArabia 17(4):109–156 Aqrawi AA M, Goff JC, Horbury AD, Sadooni, FN (2010) The petroleum geology of Iraq. Scientific Press, Beacomsfield, p 424 Archiac EJD d’ (1843) Description géologique du département de l’Aisne. Mém Soc géol Fr, 1 5(3):129–418 Barattolo F (1984) Su alcuni organi riproduttori isolate di Dasicladacee nel Cretacico dell’Appennino. 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