Cornulitids (tubeworms) from the Late Ordovician Hirnantia fauna of Morocco

Journal of African Earth Sciences 137 (2018) 61e68

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Cornulitids (tubeworms) from the Late Ordovician Hirnantia fauna of Morocco
rrez-Marco a, Olev Vinn b, * Juan Carlos Gutie a b


gicas, Jos
Instituto de Geociencias (CSIC, UCM), Departamento de Paleontología, Facultad de Ciencias Geolo e Antonio Novais 12, E-28040 Madrid, Spain Department of Geology, University of Tartu, Ravila 14 A, 50411 Tartu, Estonia

a r t i c l e i n f o

a b s t r a c t

Article history: Received 21 June 2017 Received in revised form 7 September 2017 Accepted 4 October 2017 Available online 5 October 2017

Two species of cornulitids, Cornulites gondwanensis sp. nov. and C. aff. shallochensis Reed are described from the Hirnantian of Morocco, within an assemblage representative of the Hirnantia brachiopod fauna occurring near the Ordovician South Pole. The dominance of aggregated and solitary free forms could be explained by particular sedimentary environments preceding the Hirnantian glaciation and the latest Ordovician Extinction Event. The diversity of cornulitids in the Late Ordovician of Gondwana and related terranes was relatively low, and less diverse than the cornulitids of Laurentia and Baltica. Hirnantian cornulitids from Morocco do not resemble Late Ordovician cornulitids of Baltica and Laurentia. Moroccan cornulitids seem to be closely allied to some older Gondwanan cornulitids, especially Sardinian ones. They resemble species described from the Late Ordovician and Llandovery of Scotland suggesting a palaeobiogeographic link. © 2017 Elsevier Ltd. All rights reserved.

Keywords: Cornulitida Hirnantian Second Bani Group Hirnantia fauna North Africa Morocco South Gondwana

1. Introduction Most palaeogeographical maps place present-day Northwest Africa near the Ordovician South Pole, an area almost completely covered by the Gondwana ice sheet developed during the Hirnantian glaciation (Ghienne et al., 2007, 2014; Torsvik and Cocks, 2017). Late Ordovician strata pre-dating the glaciation outcrop extensively in the Anti-Atlas range of southern Morocco, consisting essentially of sandstones and shales, very fossiliferous, deposited in a diverse range of shallow marine environments (Destombes et al., 1985). Due to the extremely high palaeolatitudinal position of the area, there is not local sedimentary or palaeontological evidence of the global warming event that affected the nearby areas of Libya and southwestern Europe during the mid to late Katian age (Fortey and Cocks, 2005). This is the reason why the widespread Nicolella brachiopod fauna and associated trilobites were never recorded in the studied region of Morocco (Colmenar, 2015). We here describe some cornulitids (tubeworm-like fossils)

* Corresponding author. Department of Geology, University of Tartu, Ravila 14 A, 50411 Tartu, Estonia.
rrez-Marco), [email protected] E-mail addresses: [email protected] (J.C. Gutie (O. Vinn). https://doi.org/10.1016/j.jafrearsci.2017.10.005 1464-343X/© 2017 Elsevier Ltd. All rights reserved.

recorded among the Late Ordovician Hirnantia fauna of the Moroccan Anti-Atlas. This fauna represents a special assemblage of brachiopods and trilobites developed just before the endOrdovician glaciation and which becomes widespread as an opportunistic fauna, from high to nearly tropical palaeolatitudes, during the Hirnantian glaciation (Rong and Harper, 1988; Harper et al., 2013). The occurrence of the Hirnantia fauna in the Ordovician of the Anti-Atlas was reported by Havlí cek (1971), Mergl (1983), Destombes et al. (1985), Villas et al. (2006) and Colmenar
and Alvaro (2015), being distributed in the pre-glacial and synglacial sediments of the Second Bani Sandstone Group. Here we describe the cornulitid remains recorded from the Lower Second Bani Formation of the aforementioned group, whose existence was first mentioned by Destombes et al. (1985) and Destombes (2006a), but never figured or studied in detail. Cornulitids belong to encrusting tentaculitoid tubeworms. They are evolutionarily closely-related to free-living tentaculitids (Vinn and Mutvei, 2009; Vinn, 2010). Their zoological affinities have long been debated, but they presumably belong to the Lopho
, 2012) and probably represent throchozoa (Vinn and Zaton stemgroup phoronids (Taylor et al., 2010). Traditionally, cornulitids constitute a family with four genera: Cornulites Schlotheim, 1820, Cornulitella Nicholson, 1872a, Conchicolites Nicholson, 1872b, and

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Kolihaia Prantl, 1946, but the latter genus has since been removed from cornulitids and placed among the cnidarians (Kri z et al., 2001). In addition, a new Devonian cornulitid genus with reticulate ornamentation, Reticornulites Lardeux et al., 2003, was described from the Armorican Massif, and a new Silurian cornulitid genus, Septalites Vinn, 2005, was reported from the Silurian of Gotland, Sweden. Cornulitids are palaeoecologically important as hard-substrate encrusters that retain their original position on the substrate after fossilisation (Taylor and Wilson, 2003). They are found only in open marine deposits. In contrast, their close relatives, the micro
et al., 2012). conchids, lived in waters of various salinities (Zaton Cornulitids commonly occur as encrusters on various invertebrate skeletons in the Upper Ordovician of North America, South America, China and Baltica (Morris and Rollins, 1971; Richards, 1974; Morris and Felton, 1993, 2003; Zhan and Vinn, 2007; Vinn, 2013;
rrez-Marco, 2016). The palaeoecology of Late Vinn and Gutie Ordovician cornulitids has been well studied in North America and China (Morris and Rollins, 1971; Morris and Felton, 1993, 2003; Holland et al., 2001; Zhan and Vinn, 2007). They have often been found cemented on brachiopod shells and due to their orientation on the valves they are thought to have benefited from the feeding currents of their hosts (Hoare and Steller, 1967; Schumann, 1967; Kesling and Chilman, 1975; Zhan and Vinn, 2007). Cornulitids € first appeared in the late Middle Ordovician of Baltoscandia (Opik, 1930; Vinn, 2013) and North America (Richards, 1974), became globally distributed in the Late Ordovician (Fisher, 1962; Richards,
rrez-Marco, 2016), 1974; Zhan and Vinn, 2007; Vinn and Gutie and became extinct by the end of the Carboniferous (Fisher, 1962; Richards, 1974). Cornulitids have hitherto been almost unknown in the Ordovician of North Africa. Besides the previous mentions of Cornulites sp. in the Upper Ordovician of Morocco (Ktaoua and Upper Bani groups: Destombes et al., 1985; Destombes, 2006a; Ghienne et al., 2014), there are no systematic descriptions on the African cornulitids. The only illustration of this fossil group from this area of Gondwana is an assemblage of poorly preserved specimens that occur as epibiont encrusters on the body chamber of one ortho€tte (late Hirnantian conic cephalopod from the Soom Shale Lagersta of South Africa: Gabbott, 1999). However, this record was omitted in a recent compilation about this extraordinary fossil biota (Gabbott et al., 2017). Nonetheless, cornulitids bear important palaeoecological information, and their detailed systematic study helps to better reconstruct some ecosystems of the Ordovician of Gondwana. The aims of the current paper are: (1) the systematic description of the cornulitid tubeworm fossils from the latest Ordovician of Morocco, which represent the highest palaeolatitudinal record for the group in the Ordovician, and (2) to discuss the diversity, ecology and palaeobiogeographical distribution of Late Ordovician cornulitid tubeworms. 2. Geological background and localities The study area (Fig. 1) is situated in the Central Anti-Atlas region of southern Morocco, 33.4 km west-northwest of the town of Tagounite, and about 30 km southwest of the city of Zagora. The succession of the Upper Ordovician is essentially represented here by the siliciclastic rocks of the Ktaoua and Second Bani groups, regionally described by Destombes et al. (1985) and mapped at a
ologique, 1989). local scale by Destombes (in Service de la Carte Ge The age of the formations included in both lithostratigraphic
rrezgroups was recently reviewed by Loi et al. (2010) and Gutie Marco et al. (2017). The main studied section (Fig. 2) corresponds to the eastern end

of the Aït Isioul cuesta, formed by the sandstones of the Upper Tiouririne Formation dipping south at a gentle angle (5e8
). Above this unit, the massive green shales with nodules of the Upper Ktaoua Formation pass upwards to the sandstones and bioturbated shales of the Lower Second Bani Formation, which forms the second and prominent escarpment (bani ¼ mountain) of the regional Ordovician outcrops. The section of Aït Isioul is located south of the Oued Moulili (an ancient river course) and west of Sidi Bou Et Twama (¼ Sidi Touhama) according to the information of J. Destombes. He published a stratigraphic log (Destombes, 2006b, Fig. A23 left) lacking the accompanying description relative to the Second Bani Group, by comparison with the manuscript of the same work (Destombes, 1983). The section involves his fossil localities 1614e1617 (from year 1966) and 2098e2099 (from year 1974), all placed in the Lower Second Bani Formation. An additional section in the same beds was also studied 10.8 km west of the Foum el Fehamiya pass and 27 km northwest of Tagounite (Fig. 1). It corresponds to J. Destombes' fossil localities 1627e1630 (from year 1966), 2014e2015 (year 1974) and 2151e2155 (year 1975), all of them belonging to the Lower Second Bani Formation. A synthetic log with the main biostratigraphical data derived from both localities was presented by Destombes et al. (1985, Figs. 37 and 38), documenting the existence of several sandstone bodies (beds ‘C’ to ‘G’) within the Lower Second Bani Formation, that were all referred to the ‘Upper Ashgillian’ (Hirnantian according to Destombes, 2006a). However, work in progress by Villas et al. (2016a, 2016b) led to the discovery of some upper Katian brachiopods and trilobites just above bed ‘G’. This implies that, at least in the section west of Tagounite, the Katian/Hirnantian boundary lies towards the lower part of the Lower Second Bani Formation and Group. The earliest Hirnantia fauna occur in the Aït Isioul section only 11e15 m above the top of bed ‘G’ (Fig. 2), whereas all the previous records listing this fauna in the literature were higher, derived from bed ‘F’ upwards, and extending their upper range to the upper part of the Upper Second Bani Formation (see Destombes et al., 1985). In the present paper we have examined the cornulitids collected from bed ‘F’ of the Aït Isioul section (Fig. 2), where these fossils become abundant in some bedding planes marked by the accumulation of disarticulated crinoid columnals, and where they occur in association with rare bivalves and gastropods, echinoderms and isolated valves of brachiopods, like Eostropheodonta, Hirnantia sagittifera (McCoy) and Plectothyrella. The latter genera are key elements of the Hirnantia fauna of the Hirnantian Stage at a global scale (Rong and Harper, 1988). Cornulitid remains become rarer in the section west of Foum el Fehamiya. This is because fossiliferous beds are in a higher stratigraphical position with regard to the previous section, possibly involving beds ‘C’ and ‘D’ of Destombes et al. (1985), deposited in somewhat shallower environments. Besides the typical Hirnantia brachiopod fauna, Hirnantian trilobites of the typical MucronaspisCalymenella assemblage were also collected from these strata. 3. Material and methods Material was collected during fieldwork in 2015 and 2016. Collected specimens were preserved as external and internal moulds in fine to medium-grained quartzitic sandstones (Fig. 3). Latex casts were made from all of the collected external moulds in order to better compare the specimens with well-preserved material from the Late Ordovician of North America, China and Estonia, but also with other similarly-preserved cornulitids from Peru. The latex casts were whitened with MgO and photographed with a scale

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Fig. 1. Satellite images showing the location of the studied area in the Anti-Atlas region of Morocco (square and arrow on the left) and enlargement of the previous site (right) with the position of the Aït Isioul (1) and Foum el Fehamiya (2) sections in the Lower Second Bani Formation (Late Ordovician). JB, Jbel Bani escarpment (First Bani Group); AI, Aït Isioul escarpment (Ktaoua Group); SB, Second Bani escarpment (Second Bani Group); FF, Foum el Fehamiya pass. N-9 and N-12 refer to Moroccan national roads. Images adapted from Google Earth ©2017.

Fig. 2. Panorama of the northern branch of the Aït Isioul section, west of Tagounite (Morocco), with the approximate location of the lithostratigraphic boundaries of Late Ordovician formations. Beds ‘G’ and “F” after Destombes et al. (1985). HF, lowest stratigraphic occurrence of the typical Hirnantia fauna (Hirnantian); Cg, Type locality and horizon of Cornulites gondwanensis sp. nov. Encircled in the left foreground is a 5 m-long car. Geographic North to the left.

bar using a Canon EOS 5D digital camera with a Canon CompactMacro EF 100 mm. Figures were compiled using Adobe Photoshop CS6 Extended. The original specimens from which latex casts are made are housed in the collections of the Museo Geominero (Instituto Geo
gico y Minero de Espan ~ a/Spanish Geological Survey), Madrid. The lo assigned registration numbers are MGM-6809X to MGM-6824X.

4. Systematic palaeontology Class Tentaculitida Boucek, 1964 Order Cornulitida Boucek, 1964 Family Cornulitidae Fisher, 1962 Genus Cornulites Schlotheim, 1820

Type species e Cornulites serpularius Schlotheim, 1820, Silurian of Gotland, Sweden.

4.1. Cornulites gondwanensis sp. nov. (Figs. 3AeB and 4AeC, EeF) Type material. Holotype is right specimen in cluster Fig. 4A, Paratypes are three specimens to the left in cluster Fig. 4A (MGM6809X-1). 28 paratypes include more than 16 specimens preserved in clusters (MGM-6809X-2 e MGM-6818X, MGM-6823X e MGM6824X) and 12 samples with isolated tubes (MGM-6816X e MGM-6818X, MGM-6824X). Type locality and horizon. Morocco, Central Anti-Atlas, Aït Isioul section about 33.4 km west of Tagounite, and 30 km southwest from Zagora. Geographic coordinates for the stratotype: 30
040

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Fig. 3. Natural examples of preservation of the studied material. A, cluster of Cornulites gondwanensis sp. nov. preserved as external moulds with desert patina, MGM-6823X-1/3. B, Undetached internal mould of C. gondwanensis sp. nov., showing the thickness and contour of conch (centre), and two isolated internal moulds of the same species (over the sample, to the left), MGM-6824X-1/3. Aït Isioul section. Scale bars, 5 mm.

41.400 lat N, 05
540 25.200 long W. It is placed in the lower part of bed ‘F’, just above the base of the lower member of the Lower Second Bani Formation (¼ base of the Second Bani Group). Pre-glacial Hirnantian strata, dated by the association with the Hirnantia brachiopod fauna and by the stratigraphical context. Etymology. After the Gondwanan palaeocontinent, to which North Africa belonged in the Ordovician. Diagnosis. Straight to slightly curved large tubes, expanded moderately in diameter, with sharp annular crests, ringlike. Costae well developed. Interspaces between crests relatively deep, flat and long. Description. Tubes can be free and solitary or form aggregations of up to five tubes. Mostly similar growth stages are present in a single aggregation. A few tubes seem to have been cemented to brachiopod shells at their proximal part. Tubes are large, mostly straight, but some are curved to slightly sinuous. They are 23e47 mm long and have apertures 4.5e6.0 mm wide. The tube wall is relatively thin. Tubes increase moderately in diameter. Tube divergence angle is 8
to 10
. Tubes covered externally with prominent well-developed and rather regularly shaped annulations. There are four to five annuli per 10 mm of tube at the aperture. The dimensions of annuli gradually, but somewhat irregularly, increase with the growth of the tube. The crests of annuli are sharp and the spaces between the annular crests are deep and flat. Tubes do not bear attachment scars and have no widened tube bases. Internal annuli are prominent and have a regular shape; they are 2.0e2.2 mm wide at the aperture of moderately sized specimen. The tubes are externally covered by well-developed, regular and fine longitudinal costae. There are four to five costae per 1 mm at a tube diameter of 5.5 mm. Discussion. The new species closely resembles Cornulites girvanensis Reed, 1923 (p. 275, pl. 12, Figs. 1, 1a) from the Llandovery of Scotland by its size and shape of annulation. It differs by a larger angle of tube divergence and better-developed longitudinal costae. The new species also resembles Cornulites shallochensis Reed, 1923 (p. 275, pl. 12, Figs. 8, 8a-b) from the Whitehouse Group (Late Ordovician) of Scotland by its moderately expanding tube and welldeveloped annuli. It differs by larger size, less regular annulation

and somewhat less concave interspaces of annuli. Cornulites gondwanensis has some resemblance to C. vilcae Vinn and
rrez-Marco, 2016 (p. 93, Fig. 2EeF) from the Sandbian of Gutie Peru by its size and well-developed annulation. It differs from C. vilcae by presence of well-developed longitudinal costae and less concave annular interspaces. The new species has also some resemblance to Cornulites caputaquae Vinassa, 1927 (p. 452, pl. 2, Fig. 7) from the Late Ordovician of Sardinia by its size and welldeveloped annulation. It differs from C. caputaquae by less concave annular interspaces and wider annular crests.

4.2. Cornulites aff. shallochensis Reed, 1923 (Fig. 4D) Material. Six clusters or complete single tubes from the Aït Isioul section (MGM-6819X-1/3 e MGM-6821X), plus one complete tube from Foum el Fehamiya locality (MGM-6822X). Description. Tubes are free solitary or form small aggregations of up to four tubes. Growth stages do not vary within a single aggregation. Tubes are usually of moderate size, mostly straight, but some can be slightly curved. They are 30e41 mm long and have apertures 2.5e4.9 mm wide. Tubes slightly expand in diameter, with tube divergence angle of 7
to 8
. Tubes covered externally with prominent well-developed and somewhat irregularly shaped annulations. There are five to six annuli per 10 mm of tube at the aperture. The dimensions of annuli increase gradually, but somewhat irregularly, with the growth of the tube. The crests of annuli are rather sharp and the spaces between the annular crests are moderately deep and slightly concave. Tubes do not show attachment scars or widened tube bases. Internal annuli are prominent and have more regular shape than external annuli. Tube external surface is devoid of any fine ornamentation in form of costae or growth lines. Discussion. Cornulites aff. shallochensis closely resembles C. shallochensis Reed, 1923 by the shape of annuli. It differs by slightly smaller tube divergence angle and larger size. Cornulites shallochensis is also an older species, known from Katian (Late Ordovician) of Scotland.

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Fig. 4. A, Cluster of Cornulites gondwanensis sp. nov., right tube in the cluster is the holotype, MGM-6809X-1/4; B, magnification of three specimens of cluster A; C, cluster of C. gondwanensis sp. nov., MGM-6810X-1/2; D, cluster of Cornulites aff. shallochensis Cowper Reed, 1923, MGM-6819X-1/3; E, single tubes of C. gondwanensis sp. nov., MGM-6817X-1/ 6; F, single tube of C. gondwanensis sp. nov., MGM-6818Xa-1. All from locality 1 (Aït Isioul). Scale bars, 5 mm.

5. Palaeoecological remarks All the studied cornulitids occur in open marine shelf sediments, within a general regressive trend in the Lower Second Bani Formation efrom bed ‘G’ to the top of bed ‘F’. The early cornulitids had colonized various marine sedimentary environments already by the Sandbian, but they preferred shallow waters (Vinn and
rrez-Marco, 2016). Usually cornulitids were very common in Gutie the shallow waters of carbonate platforms (Vinn, 2013), but in the Late Ordovician of Morocco they occurred in siliciclastic strata involving high-energy marine shelf. The recurrent low-diversity assemblage of the Hirnantia fauna, dominated by few

brachiopods ein part endemicse in quartzitic sandstone lithofacies, is interpreted as having developed in shoreface environments of Benthic Assemblage 3 (BA-3) along the Gondwanan margin. The occurrence in the same strata of aggregative growth forms of cornulitids composed up to five tubes, as well as free forms, deserves some palaeoecological interest. Secondarily free cornulitids esubstrate-cemented as juveniles onlye have been interpreted as an adaptation to live esemiinfaunallye in soft sediment, under conditions of relatively high sedimentation (Vinn, 2010). They were probably functional analogues of secondarily free, soft-sediment dwelling recent serpulids and might also have been able to correct their position in sediment

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similarly to the modern free-living serpulid Ditrupa (ten Hove and Smith, 1990; Vinn, 2010). Aggregative cornulitids have been interpreted as an adaptation to live in soft sediment with limited hard substrate available, or alternatively as an adaptation to take advantage of a restricted food source in case of symbioses (Vinn, 2010). Abundance of aggregative growth forms and secondarily free forms in the Late Ordovician of Morocco contrasts with the situation in the Ordovician of Baltica where all the adult cornulitids are attached to brachiopods (Vinn, 2013). The situation resembles somewhat that of the Sandbian of Peru where aggregative forms
rrez-Marco, 2016). However, cornulitids dominate (Vinn and Gutie attached to brachiopods are also common in the Sandbian of Peru
rrez-Marco, 2016) but they are rare or absent in (Vinn and Gutie Morocco. In Morocco most of cornulitids were attached to substrate as juveniles only. The dominance of aggregative forms and solitary free forms could be explained by peculiar sedimentation environ
rrez-Marco (2016) suggested that aggregaments. Vinn and Gutie tive growth forms may have been more efficient in siliciclastic basins such as in the Sandbian of Peru. However, aggregation is often seen in Silurian cornulitids from carbonate facies of Baltica (Vinn and Wilson, 2013), Britain and North America (Hall, 1847, 1888). It is also possible that in decalcified siliciclastic rocks, cornulitids may not be so easily noticed when encrusting brachiopods; however, aggregations of tubes would be much more conspicuous
rrez-Marco, 2016). (Vinn and Gutie No concurrence of aggregative forms and secondarily free forms has been described from carbonate platform sediments of Late
rrezOrdovician of Estonia (Baltica) (Vinn, 2013). Vinn and Gutie Marco (2016) suggested that it is possible that cornulitids occurring in siliciclastic basins, as it was exemplified by the Peruvian and Moroccan records, may have had more diverse life modes as compared to cornulitid faunas of carbonate platforms. 6. Diversity Late Ordovician cornulitid diversities of Morocco (N ¼ 2) and Peru (N ¼ 2), both from Gondwana, appear to be similar. There is single species C. scalaris known from the Spanish part of the Gondwana (Verneuil and Barrande, 1855) and single “Tentaculites anglicus” described from equivalent Katian strata of the Montagne Noire region of southeastern France (Dreyfuss, 1948). But these old data need revision, and cornulitids were recently illustrated from southeastern France by Colmenar et al. (2013, Fig. 6Se6T) and
Alvaro et al. (2016, Fig. 7i), occurring in association with Katian brachiopods. The Ordovician cornulitid record of Czech Republic (Bohemia) is also restricted to Upper Ordovician strata (Barrande, 1867), with two species, C. confertus Barrande, 1867 and C. mescai (Prantl, 1948) reported from different Sandbian to Katian formations, plus a single specimen derived from Hirnantian strata (listed k, 1966, pl. 16, Fig. 13). Six as Tentaculites sp. by Havlícek and Vane cornulitid species have been described from the Katian of Italy (Sardinia) (Meneghini, 1857; Vinassa de Regny, 1927; Spano, 1974) with some resemblance (Spano, 1974) to rare Late Ordovician cornulitids from Scotland (Cowper Reed, 1923). However, these records are different from the Moroccan taxa although surely need re-examination. It seems that diversity of cornulitids in the Late Ordovician of Gondwana and related terranes was relatively low everywhere. The cornulitid diversity in the Late Ordovician of China is even lower, comprising only a single species (Zhan and Vinn, 2007). Ordovician cornulitids from North America (Hall, 1847, 1888) and Baltica (Vinn, 2013) seem to be more diverse than faunas from Gondwana (Morocco, Spain and Peru). The Katian fauna of cornulitids is relatively rich in Baltica (Estonia), where seven species

occur, with a maximum of three species occurring together (Vinn, 2013). Similarly to Morocco, two cornulitid species eCornulites annulatus (Schlotheim, 1820) and C. scalaris (Schlotheim, 1820)e occur in the Late Ordovician of Britain (Avalonia) (Murchison, 1839). One could conclude that diversity of cornulitids was generally not high anywhere in the Late Ordovician. 7. Palaeobiogeography Fossil sites on the Mediterranean margin of Gondwana, including those in Morocco, were located in high latitudes during most of the Ordovician, distant from the Laurentian, Kazakh, northern Chinese and Eastern Gondwanan localities, which were situated in the tropics (Harper et al., 2013). The Hirnantian is mostly represented in the Mediterranean area by the typical opportunistic assemblages of brachiopods and trilobites of worldwide distribution, which have their ancestors in peri-Gondwanan cool-water
rrez-Marco et al., 2017). Cornulitids faunas (Colmenar, 2015; Gutie had a relatively wide distribution in southern Gondwana. In addition to Morocco, they occur in Bohemia (Barrande, 1867), Spain (Verneuil and Barrande, 1855), France (Dreyfuss, 1948) and Sardinia (Spano, 1974). Cornulitids are also known from the temperate re
rrez-Marco, 2016). Hirgions (Peru) of Gondwana (Vinn and Gutie nantian cornulitids from Morocco do not resemble Late Ordovician cornulitids of Baltica (Estonia) (Vinn, 2013) and Laurentia (USA) (Hall, 1847, 1888) as one could except considering the palaeogeographic distances. There is some resemblance to other Gondwanan cornulitids, especially to those from Sardinia (Meneghini, 1857; Vinassa de Regny, 1927; Spano, 1974) which was located near Morocco in the Late Ordovician. However, southern Gondwanan cornulitids from the Late Ordovician of Bohemia (Barrande, 1867) are not similar to Hirnantian cornulitids of Morocco. The slightly
rrez-Marco, 2016 from the older Cornulites vilcae Vinn and Gutie Sandbian of Peru resembles Cornulites gondwanensis, which may indicate a palaeobiogeographic link along coeval west-east periGondwanan migration routes operating from intermediate palaeolatitudes to high palaeolatitudes during the Ordovician
rrez-Marco et al., 1999). Surprisingly Moroccan cornulitids (Gutie are also similar to species described from the Late Ordovician and Llandovery of Scotland (Reed, 1923) suggesting either a morphologic convergence among speciation lines, or alternatively a palaeobiogeographic link perhaps related to the Late Ordovician ‘provincial breakdown’ (Fortey, 1984), reinterpreted in modern terms by the effects of the cooling or warming events previous to the end-Ordovician glaciation. 8. Conclusions The Hirnantian rocks of Morocco provide the highest palaeolatitudinal record of Ordovician cornulitids, and the third known occurrence of the group near the end of this period. However, other Hirnantian cornulitids reported from Bohemia (Havlícek and k, 1966) and South Africa (Gabbott, 1999) are based on Vane poorly preserved, unidentifiable specimens. The fact that the cornulitids here studied occur in association with a typical pre-glacial Hirnantia brachiopod fauna is of special interest, because the group is not represented eat a global scalee in the late Hirnantia fauna coeval with the Hirnantian glaciation, except for a single mention of cornulitid remains in the lower member of the Upper Second Bani
Formation (Colmenar and Alvaro, 2015, p. 614). Moroccan cornulitid species may occur both as aggregates of tubes or as free forms in the adult stage within a shoreface environment, indicating more diverse life modes by comparison to either encrusting or aggregative cornulitid faunas of carbonate platforms of continents in lower palaeolatitudes. Abundance and

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diversity of cornulitids in the shallow siliciclastic environments of southern Gondwana was relatively low during the Late Ordovician. Acknowledgements
nchez, The authors express their gratitude to Julio Martín Sa Diego C. García-Bellido and Saturnino Lorenzo for field assistance, Jorge Colmenar (University of Copenhagen) for the brachiopod identifications and Carlos Alonso (Complutense University, Madrid) who made the photographs of specimens. Financial support to O.V. was provided by an Estonian Research Council project IUT20-34 ‘The Phanerozoic journey of Baltica: sedimentary, geochemical and biotic signatures of changing environment e PalaeoBaltica’. Fieldwork in Morocco (J.C.G.-M.) has been supported by the IBEROR project (ref. CGL2012-39471/BTE) of the Spanish Ministry of Economy, Industry and Competitiveness. This paper is a contribution to project IGCP 653 ‘The onset of the Great Ordovician Biodiversification Event’. References
Alvaro, J.J., Colmenar, J., Monceret, E., Pouclet, A., Vizcaïno, D., 2016. Late Ordovician (post-Sardic) rifting branches in the North Gondwanan Montagne Noire and Mouthoumet massifs of southern France. Tectonophysics 681, 111e123. ^me Silurien du centre de la Bohe ^me, 1e re Partie: Recherches Barrande, J., 1867. Syste
ontologiques. Vol. III. Texte et 16 Planches. Classe des Mollusques. Ordre des Pale
ropodes. Chez l’auteur et e
diteur; Prague (xv þ 179 pp., 16 pl). Pte Bou cek, B., 1964. The Tentaculites of Bohemia. Publication of Czechoslovakian Academy of Sciences, Prague, 125 pp. Colmenar, J., 2015. The arrival of brachiopods of the Nicolella Community to the Mediterranean margin of Gondwana during the Late Ordovician: palaeogeographical and palaeoecological implications. Palaeogeogr. Palaeoclimatol. Palaeoecol. 428, 12e20.
Colmenar, J., Alvaro, J.J., 2015. Integrated brachiopod-based bioevents and sequence-stratigraphic framework for a Late Ordovician subpolar platform, eastern Anti-Atlas, Morocco. Geol. Mag. 152, 603e620. Colmenar, J., Villas, E., Vizcaïno, D., 2013. Upper Ordovician brachiopods from the Montagne Noire (France): endemic Gondwanan predecessors of Prehirnantian low-latitude immigrants. Bull. Geosci. 88, 153e174. Destombes, J., 1983. Notice explicative (Cambrien moyen, Ordovicien, base du
ologique du Maroc au 200 000e de l'Anti-Atlas marocain. Silurien) de la Carte ge Chapitre A: Feuilles Zagora-Coude du Dra-Hamada du Dra. Rapport Interne du
ologique du Maroc; Rabat (48 pp., unpubl.). Service de la Carte ge
ologique au 200 000
de l'Anti-Atlas marocain. Destombes, J., 2006a. Carte ge
ozoïque infe
rieur: Cambrien moyen et supe
rieur - Ordovicien - base du Pale
ne
ral sur les me
moires explicatifs des cartes ge
ologiques Silurien. Sommaire ge
moires du Serv. Ge
ologique du au 1/200 000 de l'Anti-Atlas marocain. Notes Me Maroc 515, 1e150.
ologique au 1/200 000 de l'Anti-Atlas marocain. Destombes, J., 2006b. Carte ge
ozoïque infe
rieur. Cambrien moyen et supe
rieur-Ordovicien-base du Pale
moire explicatif, Chapitre A [written Silurien. Feuille Zagora-Coude du Dra. Me
moires du Serv. Ge
ologique du Maroc 273 bis, 1e36. in 1983]. Notes Me Destombes, J., Hollard, H., Willefert, S., 1985. Lower Palaeozoic rocks of Morocco. In: Holland, C.H. (Ed.), Lower Palaeozoic Rocks of the World, Lower Palaeozoic of North Western and West Central Africa, vol. 4. Wiley, New York, pp. 91e336.
tude ge
ologique et pale
ontologique de Dreyfuss, M., 1948. Contribution a l’e
rieur de la Montagne Noire. Me
moires la Socie
te
Ge
ologique l'Ordovicien Supe Fr. 58, 1e63. Fisher, D.W., 1962. Small conoidal shells of uncertain affinities. In: Moore, C.D. (Ed.), Treatise on Invertebrate Paleontology, Part W. Kansas University Press, Lawrence, Kansas, pp. 130e143. Fortey, R.A., 1984. Global earlier Ordovician transgressions and regresions and their biological implications. In: Bruton, D.L. (Ed.), Aspects of the Ordovician System. Palaeontological Contributions from the University of Oslo 295, pp. 37e50. Fortey, R.A., Cocks, L.R.M., 2005. Late Ordovician global warming e the Boda event. Geology 33, 405e408. Gabbott, S.E., 1999. Orthoconic cephalopods and associated fauna from the Ordo€tte, South Africa. Palaeontology 42, 123e148. vician Soom Shale Lagersta Gabbott, S.E., Browning, C., Theron, J.N., Whittle, R.J., 2017. The late Ordovician Soom €tte: an extraordinary post-glacial fossil and sedimentary record. Shale Lagersta J. Geol. Soc. 174, 1e9. Ghienne, J.-F., Le Heron, D.P., Moreau, J., Denis, M., Deynoux, M., 2007. The Late Ordovician glacial sedimentary system of the North Gondwana platform. In: Hambrey, M.J., Cristoffersen, P., Glassier, N.F., Hubbard, B. (Eds.), Glacial Sedimentary Processes and Products, International Association of Sedimentologists. Special Publication 39, Blackwell Publishing, Oxford, pp. 295e319. Ghienne, J.-F., Desrochers, A., Vandenbroucke, T.R.A., Achab, A., Asselin, E., Dabard, M.-P., Farley, C., Loi, A., Paris, F., Wickson, S., Veizer, J., 2014. A Cenozoic-

67

style scenario for the end-Ordovician glaciation. Nat. Commun. 5, 4485, 9. pp.
rrez-Marco, J.C., Ra
bano, I., Sarmiento, G.N., Acen ~ olaza, G.F., San Jose
, M.A., Gutie Pieren, A.P., Herranz, P., Couto, H.M., Piçarra, J.M., 1999. Faunal dynamics between Iberia and Bohemia during the Oretanian and Dobrotivian (late Middleearliest Upper Ordovician), and biogeographic relations with Avalonia and Baltica. Acta Univ. Carol. Geol. 43, 487e490.
rrez-Marco, J.C., Sa
, A.A., García-Bellido, D.C., Ra
bano, I., 2017. The BohemoGutie Iberian regional chronostratigraphical scale for the Ordovician System and palaeontological correlations within South Gondwana. Lethaia 50, 258e295. Hall, J., 1847. Palaeontology of New York. In: Containing Descriptions of the Organic Remains of the Lower Division of the New York System, vol. 1. Van Benthuysen, Albany (xxiiiþ338 pp.). Hall, J., 1888. Tubicolar Annelida. Natural History of New York; Palaeontology, vol. 7. Geological Survey, Albany, New York, 278 pp. Harper, D.A.T., Rasmussen, C.M.Ø., Liljeroth, M., Blodgett, R.B., Candela, Y., Jin, J., Percival, I.G., Rong, J.-Y., Villas, E., Zhan, R.-B., 2013. Biodiversity, biogeography and phylogeography of Ordovician rhynchonelliform brachiopods. In: Harper, D.A.T., Servais, T. (Eds.), Early Palaeozoic Biogeography and Palaeogeography. Geological Society, London, Memoirs 38, pp. 127e144.
moires du Serv. Havlí cek, V., 1971. Brachiopodes de l'Ordovicien du Maroc. Notes Me
ologique du Maroc 230, 1e135. ge k, J., 1966. The Biostratigraphy of the Ordovician of Bohemia. Havlí cek, V., Vane d, Paleontol. 8, 7e69. Sborník Geol. Ve Hoare, R.D., Steller, D.L., 1967. A Devonian brachiopod with epifauna. Ohio J. Sci. 67, 291e297. Holland, S.M., Miller, A.I., Dattilo, B.F., 2001. The detection and importance of subtle biofacies within a single lithofacies: the Upper Ordovician Kope Formation of the Cincinnati, Ohio region. Palaios 16, 205e217. Kesling, R.V., Chilman, R.B., 1975. Strata and Megafossils of the Middle Devonian Silica Formation. University of Michigan Paleontology Museum, pp. 1e408. Papers on Paleontology 8. Kri z, J., Fryda, J., Galle, A., 2001. The epiplanktic anthozoan, Kolihaia eremita Prantl, 1946 (Cnidaria), from the Silurian of the Prague Basin (Bohemia). J. Czech Geol. Soc. 46, 239e245. Lardeux, H., Jaouen, P.-A., Plusquellec, Y., 2003. Reticornulites reticulatus n. gen. n. sp.
rieur de la rade de Brest (Massif armoricain, (Cornulitidae) de l'Emsien supe France). Geodiversitas 25, 649e655. Loi, A., Ghienne, J.-F., Dabard, M.P., Paris, F., Botquelen, A., Christ, N., ElaouadDebbaj, Z., Gorini, A., Vidal, M., Videt, B., Destombes, J., 2010. The Late Ordovician glacio-eustatic record from a high-latitude storm-dominated shelf succession: the Bou Ingarf section (Anti-Atlas, Southern Morocco). Palaeogeogr. Palaeoclimatol. Palaeoecol. 296, 332e358.
ontologie dell’îlle de Sardaigne ou description des fossiles Meneghini, G., 1857. Pale
e par le Ge
neral A. De Lamarmora. In: De la recueillis dans cette contre me Partie, Ge
ologie, Turin & Marmora, A. (Ed.), Voyage en Sardaigne. Troisie Paris, p. 90. Mergl, M., 1983. New brachiopods (Cambrian-Ordovician) from Algeria and  Morocco (Mediterranean Province) Casopis pro Mineralogii a Geologii, 28, 337e347. Morris, R.W., Felton, S.H., 1993. Symbiotic association of crinoids, platyceratid gastropods, and Cornulites in the Upper Ordovician (Cincinnatian) of the Cincinnati, Ohio region. Palaios 8, 465e476. Morris, R.W., Felton, S.H., 2003. Paleoecologic associations and secondary tiering of Cornulites on crinoids and bivalves in the Upper Ordovician (Cincinnatian) of southwestern Ohio, southeastern Indiana, and northern Kentucky. Palaios 18, 546e558. Morris, R.W., Rollins, H.B., 1971. The distribution and paleoecological interpretation of Cornulites in the Waynesville formation (Upper Ordovician) of Southern Ohio. Ohio J. Sci. 71, 159e170. Murchison, R.I., 1839. The Silurian System Founded on Geological Researches in the Counties of Salop, Hereford, Radnor, Montgomery, Caermarthen, Brecon, Pembroke, Monmouth, Gloucester, Worcester, and Stafford; with Descriptions of the Coal-fields and Overlying Formations. John Murray, London xviþ523 pp. Nicholson, H.A., 1872a. Ortonia, a new genus of fossil tubicolar annelides. Geol. Mag. 9, 446e449. Nicholson, H.A., 1872b. On the genera Cornulites and Tentaculites and a new genus Conchicolites. Am. J. Sci. 3, 202e206. € €ge zur kenntnis der Kukruse (C2-C3-) Stufe in Eesti. Publ. Geol. Opik, A., 1930. Beitra Institution Univ. Tartu 24, 8e10. Prantl, F., 1946. Kolihaia eremita n. gen. n. sp. a new tubicolar Annelid from the  stník Kr

Cesk
Spole Silurian of Bohemia. Ve alovske e cnosti Nauk. Trída matedecka
1944e24, 1e12. maticko-prírodove Prantl, F., 1948. The genus Conchicolites Nicholson, 1872 (Serpulimorpha) in the  stník Kra
lovske
Cesk
Spole Ordovician of Bohemia. Ve e cnosti Nauk. Trída decka
1948e9, 1e7. matematicko-prírodove Reed, F.R.C., 1923. New fossils from Girvan. Geol. Mag. 60, 268e276. Richards, P.R., 1974. Ecology of the Cornulitidae. J. Paleontology 48, 514e523. Rong, J.-y., Harper, D.A.T., 1988. A global synthesis of the latest Ordovician Hirnantian brachiopod faunas. Trans. R. Soc. Edinb. Earth Sci. 79, 383e402. Schlotheim, E.F., 1820. Die Petrefaktenkunde auf ihrem jetzigen Standpunkte durch die Beschreibung seiner sammlung versteinerter und fossiler Überreste des €utert. Beckersche Buchhandlung, Gotha, 437 pp. Thier- und Planzenreichs erla Schumann, D., 1967. Die lebensweise von Mucrospirifer Grabau, 1931 (Brachiopoda). Palaeogeogr. Palaeoclimatol. Palaeoecol. 3, 381e392.

ologique, 1989. Carte Ge
ologique du Maroc Echelle Service de la Carte Ge 1/200 000.

68

J.C. Guti
errez-Marco, O. Vinn / Journal of African Earth Sciences 137 (2018) 61e68


moires du Feuille Zagora-Coude du Dra-Hamada du Dra (p.p.). Notes et Me
ologique du Maroc 273 (map only). Service Ge Spano, C., 1974. Tentaculita dell'Ordoviciano della Sardegna. Rendiconti del Semin. della Fac. Sci. dell’Universit a Cagliari 44, 187e204. Taylor, P.D., Wilson, M.A., 2003. Palaeoecology and evolution of marine hard substrate communities. Earth Sci. Rev. 62, 1e103. Taylor, P.D., Vinn, O., Wilson, M.A., 2010. Evolution of biomineralization in “lophophorates”. Special Pap. Palaeontol. 84, 317e333. ten Hove, H.A., Smith, R.S., 1990. A re-description of Ditrupa gracillima Grube, 1878 (Polychaeta, Serpulidae) from the Indo-Pacific, with a discussion of the genus. Rec. Aust. Mus. 42, 101e118. Torsvik, T.H., Cocks, L.R.M., 2017. Earth History and Palaeogeography. Cambridge University Press, Cambridge, 332 pp.
s dans les terrains Verneuil, E. de, Barrande, J., 1855. Descriptions des fossiles trouve
vonien d'Almaden, d’une partie de la Sierra Morena et des monsilurien et de de. Bull. la Socie
te
Ge
ologique Fr. [2e se
rie] 12, 964e1025. tagnes de Tole
Villas, E., Vizcaïno, D., Alvaro, J.J., Destombes, J., Vennin, E., 2006. Biostratigraphic control of the latest-Ordovician glaciogenic unconformity in Alnif (Eastern AntiAtlas, Morocco), based on brachiopods. Geobios 39, 727e737.
rrez-Marco, J.C., García-Bellido, D.C., Lorenzo, S., Villas, E., Colmenar, J., Gutie
Pereira, S., Alvaro, J.J., 2016a. The Hirnantia fauna and the stratigraphic assessment of the uppermost Ordovician in the central Anti-Atlas (Morocco). In: 35th International Geological Congress, Abstracts. American Geosciences Institute. Georef Record ID 0784685080.

rrez-Marco, J.C., Pereira, S., Alvaro, Villas, E., Colmenar, J., Gutie J.J., García-Bellido, D.,

Lorenzo, S., 2016b. Biostratigraphic assessment of the uppermost Ordovician in the central Anti-Atlas (Morocco). In: The Palaeontological Association. 60th Annual Meeting. Programme. Abstracts and AGM papers; Lyon (France), p. 52. Vinassa de Regny, P., 1927. Fossili ordoviciani sardi, parte I. Memoire della Regia Accademia Nazionale dei Lincei. Cl. Sci. Fis. 2, 437e496. Vinn, O., 2005. A new cornulitid genus from the Silurian of Gotland, Sweden. GFF 127, 205e210. Vinn, O., 2010. Adaptive strategies in the evolution of encrusting tentaculitoid tubeworms. Palaeogeogr. Palaeoclimatol. Palaeoecol. 292, 211e221. Vinn, O., 2013. Cornulitid tubeworms from the Ordovician of eastern Baltic. Carnets
ologie 13, 131e138. Ge
rrez-Marco, J.C., 2016. New Late Ordovician cornulitids from Peru. Vinn, O., Gutie Bull. Geosci. 91, 89e95. Vinn, O., Mutvei, H., 2009. Calcareous tubeworms of the Phanerozoic. Est. J. Earth Sci. 58, 286e296. Vinn, O., Wilson, M.A., 2013. Silurian cornulitids of Estonia (Baltica). Carnets
ologie. CG2013_A09. Ge
, M., 2012. Phenetic phylogenetics of tentaculitoids d extinct Vinn, O., Zaton problematic calcareous tube-forming organisms. GFF 134, 145e156.
, M., Vinn, O., Tomescu, M., 2012. Invasion of freshwater and variable marginal Zaton marine habitats by microconchid tubeworms - an evolutionary perspective. Geobios 45, 603e610. Zhan, Renbin, Vinn, O., 2007. Cornulitid epibionts on brachiopod shells from the Late Ordovician (middle Ashgill) of East China. Est. J. Earth Sci. 56, 101e108.