Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 170–178 Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology j ourna l homepage: www.e lsev ie r .com/ locate /pa laeo Palaeobiogeography, palaeoecology and evolution of Lower Ordovician conulariids and Sphenothallus (Medusozoa, Cnidaria), with emphasis on the Fezouata Shale of southeastern Morocco Heyo Van Iten a,b,⁎, Lucy Muir c, Marcello G. Simões d, Juliana M. Leme e, Antonio C. Marques f,g, Naomi Yoder h a Department of Geology, Hanover College, Hanover, IN 47243, USA b Cincinnati Museum Center, Department of Invertebrate Paleontology, 1301 Western Avenue, Cincinnati, OH 45203, USA c Department of Geology, Amgueddfa Cymru — National Museum of Wales, Cathays Park, Cardiff CF10 3NP, Wales, UK d Department of Zoology, São Paulo State University, Rubião Junior District, 18618-000 Botucatu, São Paulo, Brazil e Geosciences Institute, University of São Paulo, R. Lago 562, 05508-080, São Paulo, Brazil f Biosciences Institute, University of São Paulo, R. Matão 101, 05508-090 São Paulo, Brazil g Center for Marine Biology, University of São Paulo, São Sebastião, Brazil h Department of Marine Science, University of Southern Mississippi, Stennis Space Center, MS 39529, USA ⁎ Corresponding author at: Department of Geology, 47243, USA. E-mail addresses: vaniten@hanover.edu (H. Van Iten), (L. Muir), profmgsimoes@gmail.com (M.G. Simões), leme marques@ib.usp.br (A.C. Marques), naomi.yoder@eagles.u http://dx.doi.org/10.1016/j.palaeo.2016.03.008 0031-0182/© 2016 Elsevier B.V. All rights reserved. a b s t r a c t a r t i c l e i n f o Article history: Received 31 August 2015 Received in revised form 4 March 2016 Accepted 10 March 2016 Available online 15 March 2016 The fossil record of conulariids (Cnidaria, Scyphozoa) extends downward into the topmost part of the Ediacaran System, but the first appearance of diverse, widespread conulariids is in siliciclastic rock units of Early Ordovician age, which collectively host at least six conulariid genera. Some of these same units also contain Sphenothallus, a probable medusozoan that frequently co-occurs with conulariids in Ordovician and younger deposits. Lower Ordovician conulariid localities are distributed among five (originally) Southern Hemisphere terranes, namely Core Gondwana (Archaeoconularia, Eoconularia and Teresconularia), Armorica (Conularia azaisi), Avalonia (Archaeoconularia, Eoconularia and Exoconularia), Perunica (Archaeoconularia, Conularia and Conulariella) and South China (Conulariella). C. azaisi, currently known from the SouthernMontagne Noire (France), probably rep- resents a new genus. Sphenothallus occurs in South China, North China (Korea), Armorica (Southern Montagne Noire) and Core Gondwana (Morocco). In southeastern Morocco, Burgess Shale-type Konservat-Lagerstätten in the Fezouata Shale (Tremadocian–Floian) yield Archaeoconularia sp., Eoconularia sp. and at least one species of Sphenothallus. This low-diversity conulariid assemblage is most similar to the Tremadocian assemblage of Wales (Avalonia), which likewise consists of a single species each of Archaeoconularia and Eoconularia. In the Fezouata Shale, Archaeoconularia sp. and Eoconularia sp. frequently occur in monospecific mass associations. Such associations probably represent an original clumped distribution on the seafloor. Additionally, some Eoconularia sp. occur in V-like pairs or radial clusters, and also some specimens were attached at the apical end to a phosphatic brachiopod or to a corner sulcus of a larger specimen of Eoconularia sp. Similar conulariid/ brachiopod associations, consisting of Conularia trentonensis and Onniella sp., occur in the Upper Ordovician (Katian) Collingwood Shale of southern Ontario, Canada. © 2016 Elsevier B.V. All rights reserved. Keywords: Conulariids Sphenothallus Medusozoa Lower Ordovician Gondwana Fezouata 1. Introduction Conulariids (order Conulariida Miller and Gurley, 1896) and Sphenothallus Hall, 1847, two extinct groups of medusozoan cnidarians that produced a finely lamellar, organo-phosphatic periderm (Van Iten et al., 1992, 2006a), first appear in the uppermost Ediacaran and lower Hanover College, Hanover, IN lucy@asoldasthehills.org @usp.br (J.M. Leme), sm.edu (N. Yoder). Cambrian systems, respectively (e.g. Zhu et al., 2000; Li et al., 2004; Van Iten et al., 2014a). Sphenothallus has been reported widely from the Cambrian System (see for example Fatka and Kraft, 2013; Muscente and Xiao, 2015), but thus far Cambrian conulariids are repre- sented solely by Baccaconularia Hughes et al., 2000 from the Furongian Saint Lawrence Formation (Upper Mississippi Valley, USA), though conulariids may occur in Cambrian Stage 1 (see Van Iten et al., 2010 and references cited therein), and Paraconularia sp. has been found in the latest Ediacaran Tamengo Formation of Brazil (Van Iten et al., 2014a). The last occurrence is particularly intriguing as recent cladistic analyses (Leme et al., 2008; Van Iten et al., 2014b) posit that Paraconularia Sinclair, 1940 was a relatively apical branch on the conulariid tree. In a number of Ordovician and younger rock units, http://crossmark.crossref.org/dialog/?doi=10.1016/j.palaeo.2016.03.008&domain=pdf mailto:naomi.yoder@eagles.usm.edu http://dx.doi.org/10.1016/j.palaeo.2016.03.008 www.elsevier.com/locate/palaeo Ta bl e 1 D is tr ib ut io n of Lo w er O rd ov ic ia n co nu la ri id s an d Sp he no th al lu s [i n br ac ke ts ]. A n as te ri sk (* ) ne xt to a sp ec ie s na m e in di ca te s th at th e oc cu rr en ce is fir st re po rt ed /d oc um en te d in th e pr es en t pa pe r. Te rr an e/ lo ca lit y U ni t A ge Ta xo n or Ta xa Li th ot yp e( s) ,r ef er en ce s (− ), re po si to ri es [− ] A rm or ic a (M on ta gn e N oi re ,F ra nc e) Sa in t Ch in ia n Fo rm at io n (u pp er pa rt ) La te Tr em ad oc ia n Co nu la ri a az ai si Th or al ,1 93 5 M on ot on ou s da rk gr ay an d gr ee n cl ay st on es an d si lt st on es w it h fin e– m ed iu m sa nd y in te rc al at io ns an d si lic eo us no du le s (C .a za is io cc ur s in sh al e or in si lic eo us no du le s) (1 ) [U LF ,M U F] A rm or ic a (M on ta gn e N oi re ,F ra nc e) La M au re ri e Fo rm at io n (l ow er pa rt ) Ea rl y Fl oi an Co nu la ri a az ai si Th or al ,1 93 5 A lt er na ti ng da rk sh al es an d fin e sa nd st on es (2 ) [U LF ] A rm or ic a (M on ta gn e N oi re ,F ra nc e) La nd ey ra n Fo rm at io n La te Fl oi an Co nu la ri a cf .a za is iT ho ra l, 19 35 [S ph en ot ha llu s sp .]* Si lt y sh al e (2 ) [M U F] A va lo ni a (W al es ) D ol -C yn -A fo n Fo rm at io n Tr em ad oc ia n A rc ha eo co nu la ri a ho m fr ay i( Sa lt er ,1 86 6) Eo co nu la ri a lin na rs so ni (H ol m ,1 89 3) G ra y m ud st on e, si lt y m ud st on e an d si lt st on e w it h ra re bi ot ur ba te d sa nd st on e (3 ) [N H M , N M W ] O go fH ên Fo rm at io n Bo la ha ul M em be r Fl oi an Ex oc on ul ar ia sp .n ov .M or ti n, 19 86 In te rb ed de d m ud st on e an d si lt st on e (4 ) [N M W ] Pe ru ni ca (C ze ch Re pu bl ic ) M íli na Fo rm at io n Tr em ad oc ia n A rc ha eo co nu la ri a in si gn is (B ar ra nd e, 18 67 ) Co nu la ri a ra ri co st at a Ba rr an de ,1 86 7 D ar k sh al e w it h ch er t no du le s (5 ) [N M P] K la ba va Fo rm at io n M yt o M em be r Ea rl y– la te Fl oi an Co nu la ri el la pu rk yn ei (Ž el íz ko ,1 91 1) Co nu la ri el la ro bu st a (B ar ra nd e, 18 67 ) Co nu la ri el la su lc a (Ž el íz ko ,1 92 1) Cl ay ey sh al es w it h su bo rd in at e m ic ac eo us sh al es an d tu ff ac eo us m at er ia la nd si lic eo us no du le s (a ll th re e sp ec ie s of Co nu la ri el la oc cu r in si lic eo us no du le s) (5 ) [N M P] N or th Ch in a (K or ea ) D um ug ol Fo rm at io n Tr em ad oc ia n Sp he no th al lu s sp . Li m e m ud st on e an d ar gi lla ce ou s lim e m ud st on e (6 ) So ut h Ch in a (G ui zh ou Pr ov in ce ) To ng ga o Fo rm at io n Ea rl y Fl oi an Co nu la ri el la sp .[ Sp he no th al lu s sp .] Bl ue -g ra y sh al e an d ye llo w -g re en sh al e an d si lt y sh al e (7 ) [N IG P] Co re G on dw an a A rg en ti na Sa nt a V ic to ri a G ro up Ea rl y Tr em ad oc ia n Te re sc on ul ar ia ar ge nt in en si s Le m e et al ., 20 03 Co ng lo m er at e (8 ) [I M L] So ut h- ea st er n M or oc co Fe zo ua ta Sh al e La te Tr em ad oc ia n– m id Fl oi an A rc ha eo co nu la ri a sp .* Eo co nu la ri a sp .* [S ph en ot ha llu s sp .]* G re en si lt y m ud st on e an d m ic ac eo us sa nd y si lt st on es (9 ) [C A U ,U LF ,Y PM ] Ta xo no m ic an d/ or lit ho lo gi ca lr ef er en ce s (r ef er en ce s de al in g w it h sy st em at ic pa le on to lo gy in di ca te d by a do ub le as te ri sk ): (1 ) Th or al ,1 93 5* *; K rö ge r an d Ev an s, 20 11 ;V iz ca in o et al ., 20 01 ;T or te llo et al ., 20 06 ;( 2) V iz ca in o et al ., 20 01 ;N of fk e an d N it sc he ,1 99 4; (3 ) Si nc la ir ,1 94 8* *; Ru sh to n an d H ow el ls ,1 99 8; Se nd in o an d D ar re ll, 20 08 ;( 4) M or ti n, 19 86 ** ;C op e, 19 96 ,2 00 5; (5 ) Ba rr an de ,1 86 7* *; Bo uč ek ,1 92 8* *; K ra ft an d K ra ft ,2 00 3; V an It en an d V hy la so va ,2 00 4* *; (6 ) Ch oi ,1 99 0; (7 ) V an It en et al ., 20 13 ** ;( 8) Le m e et al ., 20 03 ** ;( 9) M ar ti n et al ., in pr es s; G ut ié rr ez M ar co an d M ar ti n, 20 16 –i n th is is su e. Re po si to ri es :C A U — Ca di A yy ad U ni ve rs it y, M ar ra ke sh ,M or oc co ;I M L— Fa cu lt ad de Ci en ci as N at ur al es ,I ns ti tu to M ig ue lL ill o, Tu cu m án , A rg en ti na ;M U F— M on tp el lie rU ni ve rs it y, Fr an ce ;N H M — N at ur al H is to ry M us eu m ,L on do n; N IG P— N an jin g (C hi na ) In st it ut e of G eo lo gy an d Pa la eo nt ol og y; N M P— N at io na lM us eu m in Pr ag ue ,C ze ch Re pu bl ic ;N M W — N at io na lM us eu m of W al es (C ar - di ff ); U LF — U ni ve rs it y of Ly on ,F ra nc e; YP M — Ya le Pe ab od y M us eu m ,U SA . 171H. Van Iten et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 170–178 conulariids and Sphenothallus occur in close associationwith each other, in some cases in relatively restricted facies in which normal marine benthos such as corals, crinoids and rhynchonelliform brachiopods are rare or absent (e.g. Van Iten et al., 1996, 2012). Thus, in addition to possibly being closely related to each other phylogenetically, conulariids and Sphenothallus may have shared similar palaeoenvironmental preferences. The first appearance of multiple genera of conulariids, in localities throughout much of the world, is in Lower Ordovician formations, some of which also host Sphenothallus (Table 1). Interestingly, all currently known Lower Ordovician conulariids and Sphenothallus are from (originally) Southern Hemisphere terranes and localities, predominantly Gondwanan and peri-Gondwanan, which, with the exception of North China, generally were situated at mid- to very high palaeolatitudes (Cocks and Torsvik, 2004). In part this may reflect the fact that the Lower Ordovician rock records of the relatively few low-latitude terranes such as Laurentia are dominated by sparsely fossiliferous dolostones deposited in restricted environments (e.g. Overstreet et al., 2003), suggesting that the lack of conulariids and Sphenothallus in these regions may be, at least to some extent, caused by palaeoenvironmental or taphonomic artifacts. The most recent discoveries of Lower Ordovician conulariids are in the Santa Victoria Group of northwestern Argentina (Teresconularia; Leme et al., 2003), the Tonggao Formation of Guizhou Province, South China (Conulariella; Van Iten et al., 2013), and the Fezouata Shale of southeastern Morocco (Van Roy et al., 2015). In the last two formations, conulariids co-occur with Sphenothallus. The Tremadocian–Floian Fezouata Shale contains two exceptionally preserved fossil intervals (EPFs) yielding soft-bodied arthropods and other taxa, some of which were originally described from Burgess Shale-type biotas of early or middle Cambrian age (Van Roy et al., 2010; Martin et al., in press). Sphenothallus and two species of conulariids collectively occur in both of these intervals, one of which (60 m thick) occurs in the lower part of the formation and is late Tremadocian in age, and the other of which (15 m thick) occurs in the upper part and is mid Floian in age (Gutiérrez Marco and Martin, 2016–in this issue). Many Burgess Shale-type Cambrian faunas have been sampled intensively, yielding tens of thousands of exceptionally well-preserved fossils ranging from micro-invertebrates to chordates (e.g. Caron and Jackson, 2008; Zhao et al., 2010). Sphenothallus sp. is extremely rare in the mid Cambrian Burgess Shale (British Columbia, Canada; Van Iten et al., 2002), but to date neither this nor any other Cambrian Konservat-Lagerstätte has produced even a single conulariid. The present article addresses key aspects of the distribution, palaeo- ecology and evolution of Lower Ordovician conulariids and Sphenothallus, in the context of a parsimony-based cladistic hypothesis of phylogenetic relationships among conulariid genera (Fig. 1). We pay particular attention to the Fezouata Shale, which at present is the only Ordovician rock unit in Africa known to contain conulariids and Sphenothallus. In addition to Burgess Shale-type organisms, the Fezouata Shale has yielded exceptionally preserved conulariids exhibiting evidence of original apical attachment to phosphatic brachiopods and conulariids apparently attached to other conulariid specimens. 2. Material and methods The present study is based on review of the relevant literature and on direct examination of fossil specimens in collections of the following seven institutions: Department of Earth Sciences, Cadi AyyadUniversity, Marrakesh, Morocco (sample number prefix AA); Department of Earth Sciences, University of Lyon, France (sample number prefix UCBL-FSL); Department of Earth Sciences, Montpellier University, France (sample number prefix UM); National Museum of Wales (Cardiff, UK); Natural History Museum (London, UK); University of Michigan Museum of Paleontology (Ann Arbor, USA; specimen prefix number UMMP); and Yale University Peabody Museum (New Haven, CORONATES "Eoconularia" azaisi Conulariella robusta Conularina triangulata Eoconularia loculata Pseudoconularia grandissima Metaconularia aspersa Archaeoconularia insignis Exoconularia exquisita Glyptoconularia gracilis Anaconularia anomala Baccaconularia robinsoni Conularia quadrisulcata Ctenoconularia hispida Holoconularia humeli Notoconularia inornata Paraconularia inaequicostata Climacoconus quadratus Reticulaconularia penouili Fig. 1.Most parsimonious cladistic hypothesis of the phylogenetic relationships between 17 conulariid genera (represented by their type species) and Conularia azaisi Thoral, 1935 (length = 35, consistency index = 0.514, rescaled consistency index = 0.764). Analysis based on 18 unweighted, binary characters of the periderm polarized using coronate scyphozoans as the outgroup (see Supplemental data). 172 H. Van Iten et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 170–178 Connecticut, USA; sample number prefix YPM). Themost recent reports of Lower Ordovician conulariids and Sphenothallus are authored by one or more of the present investigators, and, with the exception of the Sphenothallus reported by Choi (1990), all other reports accepted here as valid were verified by direct examination of reposited specimens. Several of the occurrences tabulated here, namely Sphenothallus sp. from the Southern Montagne Noire (France) and this genus as well as two species of conulariids from the Fezouata Shale, are first reported in this article (Table 1). Material from the Fezouata Shale (approximate- ly 500 examined specimens, primarily conulariids) was collected near the town of Zagora (Central Anti-Atlas) by field parties under the direc- tion of B. Lefebvre (University of Lyon) and P. VanRoy (GhentUniversity (Belgium) and Yale University), during the course of multiple field sea- sons. Our phylogenetic analysis was conducted using PAUP* 4.0 b10 (Swofford, 2003) and followed the general procedures of Marques and Collins (2004), Collins et al. (2006) and Van Iten et al. (2006a, 2014b). Our character matrix is provided as Supplementary data. 3. Lower Ordovician conulariids and Sphenothallus Together with Sphenothallus, Lower Ordovician strata have yielded six genera of conulariids: Archaeoconularia Bouček, 1939, Conularia Miller in Sowerby, 1821, Conulariella Bouček, 1928, Eoconularia Sinclair, 1944, Exoconularia Sinclair, 1952 and Teresconularia Leme et al., 2003 (Figs. 2–4). Conularia azaisi Thoral, 1935 (Fig. 2A), originally described from the Saint Chinian Formation of the Southern Montagne Noire, France, has also been recorded from this region in the LaMaurerie and Landeyran formations, and identified either as Eoconularia azaisi (La Maurerie Formation) or as E. cf. azaisi (Landeyran Formation) (Vizcaino et al., 2001, Fig. 3; this paper, Table 1). This assignment may have been based in part on the presence on the faces of this species of broad, sinusoidal transverse undulations similar to those of E. loculata (Wiman, 1895), the type species of the genus (Sinclair, 1944; see also illustrations in Jerre, 1994). However, the Southern Montagne Noire species differs from Conularia, Eoconularia and all other conulariids in possessing a raised midline crossed by very fine, trochoidal (long.) transverse ribs lacking nodes and interspace ridges (Van Iten, pers. obs.; this paper, Fig. 2A). Therefore, C. azaisi probably represents a new genus. Despite these differences, our cladistic analysis (Fig. 1), which revealed three major clades within Conulariida, places C. azaisi in the clade that includes Eoconularia, Conularina and Conulariella. This group is united by a single non-homoplasic synapomorphy, namely ter- mination of the transverse ribs on the shoulders of the corner sulcus. The remaining Lower Ordovician conulariids collectively belong in the other two subclades, and thus all threemajor groupswithin Conulariida were in existence by early Ordovician times. Recent chronostratigraphical revisions (e.g. Ebbestad andHögström, 2007) prove that several previous reports of Lower Ordovician conulariids were incorrectly dated. Thus, Sinclair (1948) and Hessland (1949) together listed Archaeoconularia, Conularia and Pseudoconularia as occurring in “Lower Ordovician” strata of Baltica (more specifically Sweden, Estonia and adjacent parts of Russia), which was located at mid-high palaeolatitudes within 15° of Armorica and Perunica (Fig. 5). However, the rock units from which these conulariids were originally described, for example the “Gray Vaginatum Limestone” (= the Holen Formation; Ebbestad and Högström, 2007) and the “Orthoceras Limestone”, have since been reassigned to the Middle Ordovician (see for example Ebbestad andHögström, 2007). Although LowerOrdovician marine deposits (e.g. the Latorp and Toyen formations; Ebbestad and Högström, 2007) are present in the Baltic Basin, as yet no conulariids have been found in these strata (Olle Hints, in litteris, 2015). Therefore, while Archaeoconularia and Conularia occur in Lower Ordovician rock units of other terranes (Table 1), Pseudoconularia, which was present and widespread in the Middle Ordovician Series (Van Iten and Vhylasova, 2004), is not currently known from Lower Ordovician strata. Finally, Sendino and Darrell (2008) listed Metaconularia cf. punctata (Slater, 1907) as occurring in Floian rocks inWales. However, the spec- imens in question are from the Nant Ffrancon Subgroup, which is Mid- dle Ordovician in age (Fortey et al., 2000). Nearly all currently known Lower Ordovician conulariid localities are situated in Core Gondwana (Cocks and Torsvik, 2004) or in the peri-Gondwanan terranes of Armorica (Southern Montagne Noire), Avalonia (Wales) and Perunica (Bohemia), at high or very high palaeolatitudes (Fig. 5). One additional locality (Town of Sandu, Guizhou Province) is situated in South China, which lay astride 30°S in close proximity to Gondwanan India and the Arabian Shield (Cocks and Torsvik, 2013). Thus, nearly all known Lower Ordovician conulariid recordswere originally southward of 30°S. Furthermore, all occurrences are in siliciclastic sediments, predominantly mudstones, siltstones and fine sandstones, in some cases micaceous or with siliceous concretions/nodules (Table 1). In addition to conulariids, four localities, namely southeastern Morocco, the Southern Montagne Noire (France), South China and Korea contain Sphenothallus (Table 1; Figs. 2B, 6A): of these localities, three (Morocco, France and South China) contain both Sphenothallus and conulariids. Sphenothallus was also reported from the Prague Basin, Bohemia (Perunica) by Mergl (1997), but as the material was not illustrated, we have been unable to verify this occurrence. Fig. 2. A, Conularia azaisi Thoral, 1935 (upper Saint Chinian Formation, late Tremadocian, SouthernMontagne Noire [Armorica]; UCBL-FSL 712799; specimen whitened with ammonium chloride). B, Sphenothallus sp. (Landeyran Formation, late Floian, SouthernMontagne Noire [Armorica]; UCBL-FSL 712 485). This is the first Sphenothallus (upper arrow) reported from the Lower Ordovician System of Armorica, and it may have been attached at its apical end (upper arrow) to a rhynchonelliform brachiopod (lower arrow). Scale bars = 10 mm. 173H. Van Iten et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 170–178 4. Fezouata Shale (EPF-bearing intervals) 4.1. Conulariids At present the solemembers of the phylumCnidaria known to occur in the Fezouata Shale are Sphenothallus and conulariids, both sessile benthic medusozoans that were fully covered by a finely lamellar, organo-phosphatic periderm (Van Iten, 1992; Van Iten et al., 1992; Ford et al., in press). Destombes et al. (1985) were the first authors to report the presence of conulariids in the Fezouata Shale, but neither they nor subsequent authors (Van Roy et al., 2015) identified these fossils to lower taxonomical levels or reported the presence of Sphenothallus (though Van Roy et al., 2010 [fig. S2] misidentified their single illustrated Sphenothallus specimen as a “worm tube”). We here document the presence of one species each of Archaeoconularia and Eoconularia aswell as at least one, possibly two, species of Sphenothallus. Archaeoconularia sp. (Fig. 3A, B) and Eoconularia sp. (Figs. 3C–E, 4) are generally preserved flattened and aligned parallel to bedding, with nearly complete specimens preserving the gently arcuate apertural margin and tapering to within approximately 1 mm of the former apex. Comparisons of these specimens with previously described congeners from other terranes suggest that the Moroccan species are new. Specimens here identified as Archaeoconularia sp. (Fig. 3A, B) possess narrowly sulcate, non-thickened corners and midlines, and their faces exhibit minute, closely spaced nodes arranged in gently curving transverse rows that cross the midline without diminution or offset. From the corners the transverse rows trend toward the apical end of the periderm, but approximately half-way toward the midline they gradually change course to form shallow arcs that are convex toward the apertural end. While most specimens appear to have been on the order of 100–200 mm in length (Fig. 3B), one of the specimens examined in this study (YPM 530001) was originally at least 500 mm long. Relatively small specimens appear to be most similar to A. fecunda (Barrande, 1867) from the Upper Ordovician Zahořany Formation of Bohemia (Perunica) (Bouček, 1928), differing from this species in having the transverse node rows spaced farther apart. Speci- mens here identified as Eoconularia sp. (Fig. 3C–E, 4), originally b50mm long, exhibit a broad, shallow corner sulcus, commonly darker in color than the faces and slightly thickened internally, and their faces are crossed by smooth (non-nodose), non-thickened, sinusoidal (long.) transverse ribs similar to the primary transverse ribs of the type species, E. loculata (Holm, 1893) (see for example illustrations in Jerre, 1994). Features comparable to the finer, secondary transverse ribs of E. loculata were not discerned, but in any case these featureswere not noted in the original diagnosis of the genus (Sinclair, 1944). 4.2. Sphenothallus The Fezouata Shale contains at least two species of more or less tubular fossils (Fig. 6), one of which can be assigned unequivocally to the genus Sphenothallus. Slender, straight to very gently curved speci- mens, here identified as Sphenothallus sp. 1 (Fig. 6A; see also Van Roy et al., 2010, fig. S2), exhibit the diagnostic pair of longitudinal thicken- ings situated at the end points of the tube's greatest diameter (Van Iten et al., 1992). Except for irregular, probably taphonomically induced wrinkling of the thin peridermalwall between the longitudinal thicken- ings, the tube appears to be smooth. In addition to the discovery of Sphenothallus in the Fezouata Shale, a smooth-walled specimen of this genus has been collected from the Landeyran Formation (late Floian) of the Southern Montagne Noire (Fig. 2B). The other tubular fossil (Fig. 6B), which is likewise very gently tapered and with a subelliptical transverse crossection, nevertheless differs from non-ornamented Sphenothallus sp. 1 in exhibiting fine, regular, closely spaced transverse ridges or annulations that appear to fully encircle the tube. Also, development of the paired longitudinal thickenings appears to be very weak (and, again, the apical end is missing). For these reasons, we questionably assign this fossil to Sphenothallus, under the name ?Sphenothallus sp. 2. 5. Lower Ordovician palaeobiogeography During Early Ordovician times, the peri-Gondwanan terranes of Armorica, Avalonia and Perunica lay in close proximity to each other and to Morocco (e.g. Nysæther et al., 2002; this paper, Fig. 5). It is not surprising, then, that Archaeoconularia is known from Tremadocian strata of Avalonia, Morocco and Perunica, or that Eoconularia has been Fig. 3. Archaeoconularia sp. and Eoconularia sp. from the Fezouata Shale (Tremadocian– Floian) of southeastern Morocco (Core Gondwana; Anti-Atlas). A, Archaeoconularia sp. Single partial specimen (AA.BIZ12.03; lower EPF interval, late Tremadocian) clearly show- ing the transverse ornament (midline indicated by arrow). B, Archaeoconularia sp. Single nearly complete specimen (YPM 520208; upper EPF interval, mid Floian) preserving the arcuate aperturalmargin and broken just above the apex (arrow). C, Eoconularia sp. Single specimen (YPM 530270; left arrow) and a V-like pair (YPM 530283; left arrow), both originally attached at the apical end to a phosphatic brachiopod (arrows; lower EPF interval, late Tremadocian). D, Eoconularia sp. V-like pair (YPM 530280; lower EPF interval, late Tremadocian) composed of one small and one large specimen, both originally attached at their apical end to a phosphatic brachiopod (arrow). E, Eoconularia sp. Single nearly complete, relatively large specimen exhibiting two much smaller Eoconularia sp. arrayed along and possibly attached to one of its corners (long right arrow). Two addition- al, medium-sized specimens may be attached to another corner of the large specimen, closer to its apical end (short left arrow) (YPM 530272; lower EPF interval, late Tremadocian). Scale bars = 10 mm. Fig. 4. Eoconularia sp. (Fezouata Shale, Anti-Atlas, southeastern Morocco). Examples of monospecific mass associations. A, Slab (YPM 524407; lower EPF interval, late Tremadocian) showing approximately 30 specimens (some indicated by arrows) in an area covering approximately 120 cm2. B, slab (YPM 530276; lower EPF interval, late Tremadocian) showing 10 specimens in an area covering approximately 30 cm2. The three specimens indicated by the short arrows form a radial cluster, and they converge on a common point situated within the margins of a phosphatic brachiopod. The two specimens indicated by the long arrows constitute a V-like pair likewise situated with the point of convergence of the component conulariid specimens located within the margins of a brachiopod. Scale bars = 10 mm. 174 H. Van Iten et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 170–178 found in the Tremadoc of Avalonia and Morocco (Table 1). Likewise, Sphenothallus is now known from the Tremadoc of Armorica and Morocco as well as from South China and North China, which were located closer to the palaeoequator than were either of the two other terranes (but South China was still close to Core Gondwana). It is in- triguing that neither Archaeoconularia nor Eoconularia has been found in Armorica. A possible reason for this absence is that the Saint Chinian Formation strata that host C. azaisi differ lithologically from those of all other Lower Ordovician localities (Table 1), representing perhaps a palaeohabitat that was not suitable for other conulariids. The Tremadocian conulariid assemblage of southeastern Morocco is most similar to that of Avalonia (Wales), with both assemblages consisting of one species each of Archaeoconularia and Eoconularia. Exoconularia, known from the Floian ofWales but not from the Fezouata Shale, probably is a close relative of Archaeoconularia (Van Iten et al., 2014b; this paper, Fig. 1). Although Lower Ordovician strata of Wales have not yielded Sphenothallus, we predict that eventually they will. Of the other terranes/localities, southeasternMorocco shares a single genus, Archaeoconularia, with Perunica, but no genera with Argentina, the Southern Montagne Noire (Armorica) or South China (Table 1). Moreover, Conularia has been found only in the Tremadocian–Floian of Perunica, and Conulariella in the Floian of this terrane and South China. The latter genus does occur in Middle Ordovician (Darriwilian) strata of Armorica (Armorican Massif; Van Iten et al., 2013), which also yield Archaeoconularia, Exoconularia, Metaconularia and Pseudoconularia (Spain; Sendino and Santos, 2011). 6. Palaeoecology of conulariids 6.1. Monospecific mass occurrences A striking characteristic of Fezouata Shale Archaeoconularia sp. and Eoconularia sp., particularly of the latter species, is their great abundance and areal density compared with congeneric specimens from other Ordovician (and younger) terranes and rock units. Many of the Eoconularia specimens occur in monospecific mass associations Fig. 5. Palaeogeographical distribution of Lower Ordovician conulariid and Sphenothallus localities. Oblique southern hemisphere view drawn for ~495 Ma (Tremadocian) using BugPlates (Torsvik, 2009) and with the position of South China modified following Cocks and Torsvik (2013). Terrane and other locality abbreviations: A, Argentina; Ar, Armorica (Southern Montagne Noire); Av, Avalonia (Wales); NC, North China (Korea); Pe, Perunica (Bohemia); SC, South China (Sandu, Guizhou Province); MO, southeastern Morocco. Fig. 6. Tubular phosphatic fossils from the Fezouata Shale (Tremadocian–Floian) of southeasternMorocco (Core Gondwana; Anti-Atlas), A, Sphenothallus sp. 1. Single slightly twisted and wrinkled specimen (YPM 518162; lower EPF interval, late Tremadocian) missing the apical holdfast. B, ?Sphenothallus sp. 2. Single specimen (YPM 518106; arrow; exact age uncertain) showing numerous fine, closely spaced transverse annula- tions. Scale bars = 10 mm. 175H. Van Iten et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 170–178 consisting of up to approximately 50 specimens per 100 cm2 (Fig. 4). No such associations of this genus or other conulariids have previously been documented or reported, and HVI found none in museum collec- tions of Eoconularia from other localities (e.g. Ordovician strata near Girvan, Scotland [collections of the Natural History Museum, London; Sendino and Darrell, 2008] and the Early Silurian Manitoulin Dolostone of Drummond Island, Michigan, USA [uncatalogued material in the col- lections of the University of Michigan Museum of Paleontology, Ann Arbor; Sinclair, 1948]). In short, the assemblages of Eoconularia sp. from the EPF-bearing intervals of the Fezouata Shale appear to contain the most abundant and densely packed specimens of this or any conulariid genus ever documented (see also discussion below). The frequent occurrence of Archaeoconularia sp. and Eoconularia sp. in monospecific mass associations, in strata deposited in a low-energy environment well below fair-weather wave base (Martin et al., in press), suggests that the living conulariids were distributed in mono- specific clumps or patches that were possibly clonal in origin (Van Iten and Cox, 1992; Rodrigues et al., 2006; Van Iten et al., 2012). Although the conulariids probably underwent limited transport (as indicated by the observation that they are now oriented parallel to bedding; Van Iten et al., 2012), the alternative hypothesis that clumping resulted from purely taphonomical factors seems unlikely, especially considering the occurrence of some specimens in V-like pairs (which probably would have been disrupted had they undergone appreciable transport). In general, biological processes leading to clumping consti- tute reproductive strategies, either sexual (i.e. settlement of planulae) or asexual (e.g. budding, settlement of pseudo-planulae). As discussed for example by Marques and Collins (2004), most medusozoan cnidarians have an asexual benthic stage in their life cycle. Within this stage, one or more of the following asexual modes of reproduction may occur: polyp budding (formation of modular organisms), profuse medusa budding (including scyphozoan strobilation), and dormant cyst production (podocysts, reinforcing seasonal maintenance of benthic populations) (Arai, 1997; Robinson et al., 2014). Medusozoans collectively exhibiting these reproductive modes/strategies are similar in morphology and clustering to Archaeoconularia and Eoconularia (see for example Miranda et al., 2012). In the conulariids, three scenarios could have led to biological clumping: a) attachment of groups (clusters) of conulariids to other species such as brachiopods or to other conulariids (see discussion below); b) clustering of individual conulariids that were not connected to biological substrates or to each other; or c) formation of clonal colonies, with each clump constituting a single integrated body. 6.2. Conulariid/brachiopod associations Six of the specimens of Eoconularia sp. examined here form three V-like pairs (Van Iten et al., 2012), with the two members of each pair converging adapically toward a common point and nearly touching each other at the apical end (Fig. 3D, E). An additional six specimens form two radial clusters (Van Iten and Cox, 1992), each consisting of three specimens that converge adapically on a common point (Figs. 3E, 4B). Unfortunately, all of these specimens have been broken approx- imately one mm above the apex, which is now missing. Nevertheless, bothmembers of one of theV-like pairs preserve their aperturalmargin, and one of these specimens is approximately three times longer than the other; furthermore, the point of convergence of the pair lies within the margins of a phosphatic brachiopod (Fig. 3D). The same is also true of one of the radial clusters (Fig. 4B). Eleven other Eoconularia specimens, four of them solitary and the rest arrayed in V-like pairs (e.g. Fig. 4B), form similar associations with a phosphatic brachiopod shell (Fig. 3C, E). In all 16 cases, the apicalmost portion of the conulariid lies immediately adjacent to the brachiopod and close to its commissur- al margin, and the long axis of the conulariid is inclined at a high angle to this margin. Also in all cases, brachiopod specimens are sparse 176 H. Van Iten et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 170–178 (i.e. the areal density of brachiopods on the host slab is low). Impor- tantly, similar conulariid/brachiopod associations, involving Conularia trentonensis Hall, 1847 and Onniella sp. (a rhynchonelliform brachio- pod), occur in theUpper Ordovician (Katian) Collingwood Shale Forma- tion of southwestern Ontario, Canada. For example, the small slab illustrated here in Fig. 7 bears three radial clusters, each composed of three Conularia converging on a common point. In all three clusters, the apical regions of the component conulariids lie directly beneath the shell of a single Onniella sp., a configuration that closely resembles that of the aforementioned Eoconularia sp. Together with the Eoconularia sp./phosphatic brachiopod associations, these are the first such intimate associations of conulariids and brachiopods ever documented (see discussion below). The largest of the five Eoconularia sp. illustrated here in Fig. 3E exhibits two much smaller Eoconularia sp. arrayed along one of its corners. The two small specimens nearly touch the larger specimen at their apical ends (again broken just above the tip), and their long axes are aligned parallel to each other. On the other side of the large speci- men, two additional, mutually parallel Eoconularia sp. appear to touch their larger neighbor, though closer to its apical end. This occurrence is highly similar to a conulariid/Sphenothallus association illustrated by Van Iten et al. (1996, pl. 1, fig. 8) and consisting of twomutually parallel Fig. 7. Conularia trentonensis Hall, 1847 (Upper Ordovician [Katian], Collingwood Shale Formation, Lake Huron shoreline, southern Ontario, Canada; UMMP 73817). A, single bedding plane bearing three radial clusters (outlined by rectangular boxes), each composed of three conulariids originally attached to the shell of an Onniella sp. B, detail of one of the clusters. Scale bars = 10 mm. Climacoconus quadratus (Walcott, 1879) touching one of the longitudi- nal thickenings of the Sphenothallus tube. Van Iten et al. (1996) argued that associations similar to those de- scribed above constitute compelling circumstantial evidence of original attachment of the conulariids to the associated fossils, probably at the apical end of the conulariids. Previously documented associations consist of one ormore conulariids and the shell of a hyolith or nautiloid, a crinoid stem or Sphenothallus tube, or possible vertebrate bone (Van Iten and Südkamp, 2010; see also Van Iten et al., 1996 and references cited therein). Even though direct evidence of apical attachment is not evident (in all cases the tips of the conulariids aremissing), it seems un- likely that such associations, with their multiple, spatial coincidences, are fortuitous or taphonomic in origin. This is particularly evident for the V-like pairs (Fig. 3D) and radial clusters (Fig. 7). The fact that the conulariids converge on a common point, situated within the margins of the brachiopod, tends to rule out the hypothesis that the fossils were brought together by bottom currents, as this mechanism requires either (a) multiple cases of originally solitary conulariids being deposit- ed in such a way as to be contiguous at their apices, or (b) specimens originally arranged in V-like pairs and radial clusters undergoing transport without disruption of their original adapical convergence. Additionally, the low areal density of the specimens in question argues against these associations being merely fortuitous. Similar reasoning applies to the alternative hypothesis that the conulariid/brachiopod associations are an artifact of transport by biological agents. In short, then, it seems that the most likely explanation of multiple occurrences of conulariid/brachiopod associations such as those here documented, is that the spatial patterns now exhibited by these fossils reflect original attachment of the conulariids to brachiopod shells, most likely at the apical or adoral end of the conulariids. The same line of argument leads us to conclude that it is most probable that the two small Eoconularia sp. arrayed along a corner of a larger individual of this species (Fig. 3E), were originally attached or connected at their apex to the larger specimen. Moreover, because all three of these specimens are conulariids and members of the same species, it seems possible that the two small conulariids may not simply have been attached to the larger specimen, but rather budded from it. This hypothesis can potentially be corroborated by the discovery of specimens preserving the apex. 7. Conclusions A literal reading of the fossil record of conulariids leads to the conclusion that this medusozoan clade underwent a radiation during Early Ordovician times. However, our cladistic analysis demonstrates that the two known pre-Ordovician genera, Baccaconularia (Furongian) and Paraconularia (latest Ediacaran), occupy apical positions in the conulariid tree (Fig. 1). If this interpretation is correct, then the most recent common ancestor of all conulariids originated still deeper within the Neoproterozoic Era, and therefore multiple conulariid ghost line- ages extend downward through the Cambrian and Ediacaran periods. Rocks of the Cambrian System are widespread and have been sampled intensively, but thus far the only definitely known Cambrian conulariid locality (Hughes et al., 2000) has yielded but a single genus. Even the Cambrian Konservat-Lagerstätten have yet to produce a single speci- men of a conulariid. Notwithstanding, the fact that the mid Cambrian Burgess Shale has yielded extremely rare Sphenothallus sp., a finely lamellar phosphatic taxon that appears to be isotaphonomic with conulariids, suggests that conulariids likewise may be present but extremely rare, occurring possibly as minute fragments (conulariid “microfossils”; Jerre, 1993; Van Iten et al., 1996, 2006b), which could be recovered by means of the same rock preparation techniques used for extraction of conodonts. Conulariids and Sphenothallus in the EPF-bearing intervals of the Fezouata Shale of southeastern Morocco, introduced herein, represent the first records of these two medusozoan groups from the Lower 177H. Van Iten et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 170–178 Ordovician of Africa. Two genera of conulariids—Archaeoconularia and Eoconularia—are present, and there may also be two species of Sphenothallus (one smooth-walled and another with fine transverse ridges). Sample sizes for nearly all Lower Ordovician localities are relatively large (N30 reposited specimens per species per locality), and thus differences in the taxonomic composition of conulariids between Morocco and the four other Lower Ordovician localities (Argentina, Armorica, Perunica and South China)may reflect differences in the orig- inal palaeoenvironments and/or factors promoting faunal endemism. Archaeoconularia and Eoconularia are also present in the Lower Ordovi- cian of Wales (Avalonia), which was located adjacent to northwestern Africa; however, the sample sizes available for the Avalonian sites are much smaller than for other palaeocontinents. Thus, there may be significant undiscovered conulariid diversity in Avalonia. In addition to being relatively diverse, Lower Ordovician conulariids may also be locally abundant. In the Fezouata Shale, Archaeoconularia sp. and Eoconularia sp. commonly occur in monospecific mass associa- tions, with observed Eoconularia sp. concentrations containing up to about 50 specimens in an area of approximately 100 cm2, on the same bedding plane/lamina. Moreover, some Eoconularia sp., including specimens forming V-like pairs, show orientational evidence of original apical attachment to phosphatic brachiopods and even to other Eoconularia sp. Similar evidence of original apical attachment to rhynchonelliform brachiopods (Onniella sp.) is exhibited by radially clustered C. trentonensis from the Upper Ordovician Collingwood Shale of Ontario, Canada. This is the first time that evidence of original apical attachment of conulariids to brachiopods or to other conulariids has been documented. Finally, even though most conulariids and Sphenothallus in the EPF-bearing intervals of the Fezouata Shale probably underwent limited (local) transport immediately prior to final burial, the present occurrence of Archaeoconularia sp. and Eoconularia sp. in monospecific mass associations probably reflects an original clumped distribution of these two conulariids on the shallow seafloor. Acknowledgments Financial support for this project was provided by a major research grant from the Hanover College Faculty Development Committee to HVI. For permission to examine and/or borrow reposited conulariid and Sphenothallus specimens we thank S. Butts (Yale University Peabody Museum), D. Miller (University of Michigan Museum of Pale- ontology), J. Darrell (Natural History Museum), B. Lefebvre (University of Lyon) and L. McCobb (National Museum of Wales). We also thank B. Lefebvre and P. 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http://refhub.elsevier.com/S0031-0182(16)30001-3/rf0370 http://refhub.elsevier.com/S0031-0182(16)30001-3/rf0370 http://refhub.elsevier.com/S0031-0182(16)30001-3/rf0370 http://refhub.elsevier.com/S0031-0182(16)30001-3/rf0375 http://refhub.elsevier.com/S0031-0182(16)30001-3/rf0375 http://refhub.elsevier.com/S0031-0182(16)30001-3/rf0380 http://refhub.elsevier.com/S0031-0182(16)30001-3/rf0380 http://refhub.elsevier.com/S0031-0182(16)30001-3/rf0380 Palaeobiogeography, palaeoecology and evolution of Lower Ordovician conulariids and Sphenothallus (Medusozoa, Cnidaria), wi... 1. Introduction 2. Material and methods 3. Lower Ordovician conulariids and Sphenothallus 4. Fezouata Shale (EPF-bearing intervals) 4.1. Conulariids 4.2. Sphenothallus 5. Lower Ordovician palaeobiogeography 6. Palaeoecology of conulariids 6.1. Monospecific mass occurrences 6.2. Conulariid/brachiopod associations 7. Conclusions Acknowledgments Appendix A. Supplementary data References