Translator Disclaimer
6 June 2012 A New Species of Tiaracrinus from the Latest Emsian of Morocco and Its Phylogeny
Author Affiliations +
Abstract

We describe a new species of the unusual crinoid Tiaracrinus, T. jeanlemenni sp. nov. from the latest Emsian of the famous mudmound locality Hamar Laghdad, Morocco. It differs from the previously known species in the higher number of ribs and the vaulted rib-fields, which is corroborated by the comparison of simple quantitative characters and ratios as well as by the results of a cluster analysis and a Principal Component Analysis. Based on the new material and the published specimens, we discuss the phylogeny of the genus and suggest that T. oehlerti and T. moravicus represent the ancestral forms of this small clade.

Introduction

Palaeozoic echinoderms produced a wealth of unusual thecal morphologies, which are hard to interpret in terms of taxonomic assignment and/ or functional morphology. Although this is particularly true for Early Palaeozoic clades (e.g., Sumrall and Wray 2007), it still holds true for some Devonian forms, for example pyrgocystid edrioasteroids (e.g., Bather 1915; Dehm 1961; Holloway and Jell 1983; Klug et al. 2008; De Baets et al. 2010), some crinoids (e.g., Schmidt 1934; Bohatý 2011) or late blastozoans (e.g., Dehm 1934; Rahman and Lintz 2012). Crinoids show their highest disparity in the Ordovician, but disparity remains high until the end of the Devonian (Foote 1995). Several areas of the Palaeozoic crinoid morphospace have not been reoccupied in the Mesozoic (Foote 1999).

In recent years, we have discovered the first two specimens of the genus Tiaracrinus in Morocco. This genus is usually thought to be restricted to Early (Lochkovian) to Middle Devonian (Eifelian; see Le Menn 1987; Prokop 1987; Haude 2008), but Kříž (1992) reported some in open nomenclature from the Late Silurian (Ludfordian,). Tiaracrinus is peculiar for the following reasons: (i) the calyx shows a tetramerous symmetry; (ii) so far, it has not been found with arms, although some unusual arm structures have been assigned to the genus (see further); (iii) the theca has four fields with epispires, giving it a blastozoan appearance.

Species of Tiaracrinus based on calices were first described in the 19th century. Schultze (1866) introduced the genus with the type species T. quadrifrons in his monograph on the Middle Devonian echinoderms from the Eifel Mountains. Soon thereafter, two more species of Tiaracrinus were described, T. oehlerti Schlüter, 1881 and T. rarus (Barrande, 1887). In the 20th century, two additional species were published based on calices, T. tedraedra Jaekel, 1901 and T. moravicus Ubaghs and Bouček, 1962. Two species based on limbrachoids, unusual arm structures, have been recently assigned to Tiaracrinus with some reservation (T.? obtusibrachialis Haude, 1993 and T.? aceribrachialis Haude, 1993). Hauser (2008: 1) listed the latter two species as nomina dubia. Additional specimens in open nomenclature were reported from the Ludfordian, Lockovian, Pragian and Emsian of the Czech Republic (Prokop 1987; Kříž 1992; Prokop and Petr 2002).

Fig. 1.

Geological map (modified from Klug 2002) of the eastern Anti-Atlas showing the two localities that yielded Tiaracrinus.

f01_135.jpg

In this study, we describe and illustrate the first two specimens of Tiaracrinus from the Early Devonian of Morocco. We discuss ontogenetic changes within this group as well as its phylogeny.

Institutional abbreviations.—GFCL, collection of D. Le Maître, Laboratoire de Géologie de la Faculté Catholique de Lille, France; LPB, Laboratoire de Paléontologie de Brest, France; PIMUZ, Paläontologisches Institut und Museum, Universität Zürich, Switzerland.

Other abbreviations.—PCA, Principal Component Analysis.

Material

So far, only two specimens of Tiaracrinus have been found in the Moroccan eastern Anti-Atlas by us. Both specimens are of latest Emsian age and were found at the southern edge of Jebel Oufatene (PIMUZ 29741) and at the “red cliff” in Hamar Laghdad (PIMUZ 29739; Fig. 1). Both specimens are stored at the Paläontologisches Institut und Museum at the University of Zurich. Both specimens (Fig. 2) are slightly corroded but well preserved otherwise. The specimen from Hamar Laghdad is slightly better preserved, probably due to a partial silicification. Holdfast, stem, brachials, arms and oral plates are not preserved in both specimens.

Fig. 2.

Zophocrinid crinoid Tiaracrinus jeanlemenni sp. nov., probably late Polygnathus patulus Conodont Biozone, late Anarcestes lateseptatus Ammonoid Biozone, latest Emsian, Early Devonian, eastern Anti-Atlas Morocco. A. PIMUZ 29739, holotype, “Red cliff” at Hamar Laghdad, Tafilalt. Lateral views (A1, A2), showing the radial channel and the rib-fields; note the ornamentation in the channel near the oral surface in A2,. Aboral view (A3), note the small cross section of the trimeral basals and the low rim around it. Oral view (A4), note the ornamentation in the channel near the oral surface. Detail of A3 (A5), note the epispires and the uniform thickness of the ribs. On the top right, the subtle striation is faintly visible between the ribs. Oblique view of the aboral side (A6), showing the epispires. Due to weathering, the ribs obtained a tuberculate ornament (A7). B. PIMUZ 29741, paratype, Jebel Oufatene, Maïder. Aboral view (B1), the rib-fields are less vaulted and the cross section of the calyx less quadrate than in the holotype; the fossil on the top left is a spiriferid. Lateral views (B2, B3), showing the narrow ribs and the smooth surface of the radial channels; in the lateral aspect it looks like the radial channel is tapering towards the oral side of the cup.

f02_135.jpg

PIMUZ 29739, the larger specimen, was collected from scree atthe “red cliff” (Klug2002;N 30.82453°, W4.90210°) at Hamar Laghdad in the Tafilalt region. Hamar Laghdad is situated about 18 km ESE of the town Erfoud (Fig. 1). Hamar Laghdad has become world-renowned for its mud-mounds, some of which being completely exhumed, some others are still more or less covered by the overlying sediments (e.g., Roch 1934; Massa et al. 1965; Hollard 1974; Alberti 1982; Brachert et al. 1992; Wendt 1993; Belka 1994,1998;Bultynck and Walliser 2000; Aitken et al. 2002; Berkowski 2006; Cavalazzi et al. 2007). As far as palaeontology is concerned, this locality yielded highly diverse trilobite associations (e.g., Alberti 1969, 1982; Klug et al. 2009), abundant cephalopods (Töneböhn 1991; Klug 2001, 2002; Klug et al. 2009) including ammonoids infested by parasites (De Baets et al. 2011) as well as many blastozoans, crinoids (sometimes encysting corals: Berkowski and Klug 2012), brachiopods, rugose corals specialised on vent habitats (Berkowski 2004, 2006, 2008,2012, Belka and Berkowski 2005), locally favositids in rock-forming numbers and large bivalves (Panenka, Patrocardia and similar forms). The specimen PIMUZ 29739 was collected from marl containing limestone nodules and layers of latest Emsian age. These layers contain ammonoids of the genera Amoenophyllites, Anarcestes, and Chlupacites (Klug et al. 2009). Immediately below these marl beds, a claystone succession of late Emsian age is present, which overly the massive mudmound limestone, also of Emsian age. The latter limestone contains Mimagoniatites fecundus, thus confirming their basal Dalejan age (e.g., Klug et al. 2009). Above the marl, the layers become increasingly limy. At the base of the limestone, a dark nodule layer contains abundant Foordites veniens (Klug 2002; Klug et al. 2009). Diagenesis and taphonomy of the red cliff are discussed in Klug et al. (2009).

Fig. 3.

Bivariate plots with various measurements and ratios of some published (Le Menn 1190; Hauser 2008) and the two newly described specimens of Tiaracrinus. See the methods chapter for definition of the parameters. A. Calyx width vs. calyx height; note the clear sepration of taxa. B. Calyx shape vs. calyx height. C. Number of pore rows vs. calyx height. As in A, the new taxon is also well separated from the existing taxa. The linear trendline probably reflects an ontogenetic trend. Open squares mark the values of the new species T. jeanlemenni sp. nov., solid squares mark all other species.

f03_135.jpg

PIMUZ 29741 is somewhat smaller and was found at the southern edge of Jebel Oufatene (Fig. 1; compare Hollard 1974; Massa et al. 1965). This specimen is slightly deformed, probably due to compaction of the sediment. However, this deformation is minimal. We tested this by taking high and low estimates of the measurements. Therefore, we think that the overall proportions are reasonably well preserved. This is additionally corroborated by comparing the superficial visual similarities and differences of the measured specimens with PIMUZ 29741 with the clustering of forms in the PCA and in the cluster analysis (see the methods chapter). It was collected from a trench where locals had dug for late Emsian trilobites (N 30.824532°, W 4.90210°). Jebel Oufatene is about 14 km S of Fezzou in the Maïder region (eastern Anti-Atlas, Morocco). According to Kaufmann (1998), the entire Emsian is about 100 m thick in this area. The Dalejan (late Emsian) is represented by a thick claystone and clayey marl sequence, which displays increasing carbonate content near its top. For a sedimentological basin model of the Maïder Basin: see Döring (2002).

Methods

In order to distinguish between the species of this genus based on morphological differences, we produced bivariate plots (Fig. 3), a Principal Component Analysis (PCA; Fig. 4) and a Cluster Analysis (Fig. 5) using PAST (Hammer at al. 2001) based on the following six characters (Table 1):

Table 1.

Values used in the principal component and cluster analyses. Most of the values were taken from Hauser (1997,2008). Values with some uncertainty are given in bold.

t01_135.gif

Calyx width size class (based on the largest width): The largest specimen was set as 1.

Calyx height size class: The largest specimen was set as 1.

Curvature of the calyx walls, calculated by dividing the largest width of the oral surface (assumed to be more or less identical with the diameter of the oral edge of the radial circlet) by the maximum width of the calyx.

Stem to calyx-ratio: The ratio between the diameter of the facet of the most proximal nodal columnal and the diameter the maximum width of the calyx.

Row ratio: The number of epispire rows divided by the maximal number of epispiral rows of all known specimens.

Shape: The values of character 1 (width size class) divided by those of value 2 (height size class).

The standardisation was made for several purposes: (i) standardisation reduces the bias caused by differences in dimensions of the respective parameter; (ii) it eliminates the bias in scaling errors in those cases, where morphometric values were taken from the literature. We thus performed a PCA on the correlation matrix. The intraspecific variability is mainly caused by differences in ontogenetic trajectories (see Fig. 3) and, to a minor degree, by preservational biases such as the differences between internal moulds versus specimens that preserve the skeleton.

In the bivariate plots (Fig. 3), which were made using Excel, trendlines are given, which are supposed to show the predominant ontogenetic trend (correlation with calyx height, i.e., size). These were also produced with Excel.

The choice of specimens is based on their availability and preservation mainly. Not many well-preserved specimens of Tiaracrinus are sufficiently well documented and show all characters needed for our analyses, hence the low number of data.

Fig. 4.

PCA of some published (Le Menn 1190; Hauser 2008) and the two newly described specimens of Tiaracrinus (see Table 1). See Methods for definition of the parameters. A. Plot of principal components 1 and 2; note, how the new species separates well from the previously known ones. B. Plot of principal components 1 and 3. C. Plot of principal components 2 and 3; again, the new species is morphologically separated from the others. Open circles mark the values of the new species T. jeanlemenni sp. nov., solid squares mark all other species.

f04_135.jpg

Systematic palaeontology

Phylum Echinodermata Klein, 1754
Class Crinoidea Miller, 1821
Order Disparida Moore and Laudon, 1943
Superfamily Belemnocrinaceae Miller, 1883
Family Zophocrinidae Miller, 1892?

  • Type genus: Zophocrinus Miller, 1891.

  • Discussion.—In spite of the overall similarity in cup-shape and the organisation of the oral surface, it still appears questionable to include morphologically quite different genera such as Zophocrinus and Tiaracrinus in the same family. As far as we understand, the evolution or evolutionary reduction of epispires is probably not fully understood. We therefore keep this historical family assignment in agreement with the Treatise (Moore et al. 1978) as well as crinoid experts such as Le Menn (1990) and Hauser (2008).

  • Genus Tiaracrinus Schultze, 1866

  • Type species: Tiaracrinus quadrifrons Schultze, 1866, original designation; Stínava near Plumlov, Moravia, Czech Republic, Emsian, Early Devonian.

  • Species included: Tiaracrinus moravicus Ubaghs and Bouček, 1962; Tiaracrinus oehlerti Schlüter, 1881; “Staurosoma rarumBarrande, 1887; Tiaracrinus quadrifrons Schultze, 1866; Tiaracrinus tedraedra Jaekel in Lotz, 1901; Tiaracrinus jeanlemenni sp. nov.; “Triaracrinus” sp. (sic!) Kříž, 1992.

  • Discussion.—Initially described as a crinoid, Tiaracrinus was occasionally attributed to the Rhombifera (Blastozoa) by some early palaeontologists (Jaekel 1899, 1918; Bather 1900). Subsequently it has been consistently assigned to the crinoids (e.g., Frech 1902; Springer 1926; Bassler 1938; Moore et al. 1978; Le Menn 1990; Haude 1993; Hauser 2008). This confusion was probably largely related with its peculiar symmetry, the possible absence of arms and the presence of pores (epispires) on the theca. Here, we briefly discuss these features, their possible implications and problems associated with them:

  • (i) Symmetry: Tiaracrinus has three basais and four radiais, thus determining the tetrameral symmetry of the calyx (Le Menn 1990). The oral surface is rarely preserved but has been discussed in detail by Le Menn (1990). The calyx shows five different plate numbers per circlet in the calyx. The base shows three plates while the cup is tetrameral. On the oral surface, 13 fields with brachial platelets and eight interoral fields can be seen, which surround the five oral plates (Le Menn 1990).

  • (ii) Arms: Tiaracrinus is commonly found without arms and has been described in the Treatise on Invertebrate Paleontology (Moore et al. 1978: 562) as follows: “Arm facets obscure or absent. Arms and columns unknown”. Later, Haude (1993) assigned limbrachoids from the Middle Devonian of Germany to this genus. He discussed the problems of the systematic position of this genus: “Immerhin ist die Theka so ungewöhnlich gebaut, dass selbst bedeutende Kenner der Pelmatozoen wie Bather (1900: 57) und Jaekel (1918: 99) Tiaracrinus zu den Cystoiden stellten. (An einem Cystoiden wären im übrigen die Limbrachoide wesentlich leichter als [biseriale] versteifte Brachiolen zu interpretieren.)” [Translation: “After all, the theca is constructed in such an unusual way that even important adepts of the pelmatozoans such as Bather (1900: 57) and Jaekel (1918: 99) have assigned Tiaracrinus to the cystoids. (On a cystoid, by the way, the limbrachoids would be much easier to interpret as stiffened [biserial] brachioles.)”]

  • Le Menn (1990: 163) also discussed this issue: “Le nombre de bras demeure difficile à établir” [Translation: “The number of arms remains difficult to identify”]. While Le Maître (1958a-c) had suggested 18 arms based on 18 ditches on the oral surface, Le Menn (1990) thinks that these ditches were formed by erosion. The latter author discussed the possibilities of five or eight arms, based on the number and arrangement of oral, interoral, and brachial plates. It appears like this question has to stay unanswered until a complete, articulated specimen is found.

  • (iii) Pores on the calyx: Tiaracrinus displays four fields with epispires (Fig. 2). These epispires have been interpreted as representing a plesiomorphic character by Guensburg and Sprinkle (2007: 287): “Crinoid respiratory folds, for instance, are symmetrical internally and externally, whereas rhombiferan internal folds are extended forming interior bulges. Folds of most crinoids occur at triple junctures of plate corners, whereas those of rhombiferans cross plate sides.”

  • The origin of the type material is unknown according to Hauser (2008), but Le Menn (1987) described similar specimens from the Saint Céneré Formation (Pragian) of the “Tranchée de la voie Sablé”; Massif Armoricain (France).

  • Stratigraphic and geographic range.—Species of Tiaracrinus are recorded from: the Emsian of Plumlov (Moravia, Czech Republic), the late Emsian (according to Prokop 1987) of Koňeprusy (Bohemia, Czech Republic), the Freilingen Formation (Eifelian) of Nollenbach (Eifel, Germany), the Greifensteiner Kalk (near Emsian-Eifelian boundary) of Greifenstein (Lahn-Dill-Kreis, Germany), the Amerboh Group (late Emsian) of the eastern Anti-Atlas (Morocco), the Kopanina Formation (Ludfordian, Silurian) of Mušlovka quarry (Bohemia, Czech Republic).

  • Fig. 5.

    Cluster analysis (Euclidean, paired group) of some published specimens and the two newly described specimens (see Table 1). The cluster on the right including Tiaracrinus quadrifrons and Tiaracrinus tetraedra is supported by the bootstrap (at 500 replicates; 59%with past); the Tiaracrinus oehlerti and Tiaracrinus moravicus-group (59 and 64%) and the Tiaracrinus jeanlemenni and Tiaracrinus rarus-group (62 and 72%) are also reasonably well supported. See also the methods chapter for definition of the parameters.

    f05_135.jpg

    Tiaracrinus jeanlemenni sp. nov.
    Fig. 2.

  • 1990 Tiaracrinus rarus (Barrande, 1887); Le Menn 1990: 162, pl. 1.

  • Etymology. After Jean Le Menn, honouring his work on Palaeozoic echinoderms and his thorough description of the genus in Africa.

  • Type material. Holotype: PIMUZ 29739, a well-preserved calyx but lacking the oral surface. Paratypes: PIMUZ 29741, GFCL 2152–2153, LPB 16795.

  • Type locality. “Red cliff” at Hamar Laghdad (eastern Anti-Atlas, Morocco).

  • Type horizon: Probably late Polygnathus patulus Conodont Biozone, late Anarcestes lateseptatus Ammonoid Biozone, latest Emsian, Early Devonian (Bultynck and Walliser 2000; Klug 2002).

  • Diagnosis.—Tiaracrinus with a more or less spherical calyx, with four very broad rhomboid radial rib-fields, which are strongly vaulted and which carry a large number of slender ribs (>20), a small and narrow radial ring, narrow and with slightly concave radial channels.

  • Description.—For the description of the Algerian specimens see Le Menn (1990). The two new Moroccan specimens are described below. Specimen PIMUZ 29739, holotype (Fig. 2A). The specimen preserves only the broad subglobular calyx and measures 9 mm in height and maximally 12.9 mm in width. At the oral surface, the width of the calyx is reduced to 8.7 mm, but the oral surface is not preserved. The radial rib-field is up to 9.3 mm wide and it carries up to 22 ribs with pores at the end. In some parts, the ribs carry tubercles, but this might be due to weathering. The four radial channels form a perfect cross when seen from the aboral side. Specimen PIMUZ 29741, paratype (Fig. 2B). This calyx also lacks the oral surface, arms, and the stem. With a calyx height of 8.5 mm, this specimen is only 9.6 mm wide and therefore more slender than the holotype and the Algerian specimens. Although this specimen is slightly deformed, this difference in shape is probably original rather than a taphonomic artefact. At the oral surface, it measures only 5 mm while the other three specimens measure 8 mm or more. The ribs in the diamond-shaped rib-field appear finer but are more numerous (24) than in the other specimens. The radial channels also form a perfect cross when seen from the oral side and the rib-fields form a right angle where the channels meet.

  • Discussion.—Le Menn (1990) listed the five species Tiaracrinus moravicus, T. rarus, T. quadrifrons, T. soyei, and T. tedraedra. His assignment of the three Algerian calices to Barrande's (1887) species T. rarus was based on the globular calyx with the large number of ribs and the rhomboid ribfields, which are similar to the European species T. rarus. Both the bivariate plots (Fig. 3) and the PCA-plots of principal component 1 and 2 as well as of principal component 2 and 3 (Fig. 4) revealed, however, that all specimens of the new species plot in a field separate from those of T. rarus and the other species. By contrast, both in the cluster analysis (Fig. 5) and in the plot of principal component 1 and 3 (Fig. 4), the specimen from Jebel Oufatene (PIMUZ 29741) falls in the field of T. rarus.

  • The results of this cluster analysis (Fig. 5) of 15 specimens revealed three pairs of species, which plot in the same respective clusters (see also the phylogeny chapter). In this analysis (Fig. 5), T. rarus is the sister species of T. jeanlemenni. This is also supported by the PCA (especially the principal component 3, i.e., the width size-class and the row-ratio) and the bivariate plots (Figs. 3, 4). The separation of T. jeanlemenni from T. rarus is based mainly on the higher number of pore rows (Fig. 3C) and the lower height to width ratio in the new species.

  • Morphologically, the Algerian specimens (Le Menn 1990: pl. 1: 1–12) strongly resemble PIMUZ 29739 from Hamar Laghdad, while the slightly smaller specimen PIMUZ 29741 from Jebel Oufatene looks slightly different (Fig. 2). The question arises, whether this last mentioned specimen belongs to a separate species because it has more ribs with epispires than the other four specimens and the calyx is more slender, which might, however, be due to the slight traces of compaction or due to intraspecific variability (which cannot be quantified due to the low number of available specimens). It resembles T. rarus in the narrower oral surface but it differs from this Bohemian species in the adorally converging radial channels. Nevertheless, most of its measurements and values (Fig. 3; pore rows in relation to size, height in relation to width) plot very close to the other specimens assigned to the new species (Fig. 3, 4), and therefore we conclude that it belongs to the new species and simply represents a morphological variant.

  • Stratigraphic and geographic range.—Late Emsian of the eastern Anti-Atlas (Morocco) and Monts d'Ougarta (Algeria).

  • Growth

    As already pointed out by Le Menn (1990: 165), some of the characters of Tiaracrinus, such as the number of ribs, vary through ontogeny. The correlation of calyx width and height in the bivariate graph of Fig. 3 A is not significant (r = 0.358, R2 = 0.128, p = 0.1897), which is probably due to the fact that the graph depicts specimens from several species. Evaluation of a possible correlation with single species is, however, not possible at this point because of the lack of material and thus data. In spite of the lack of data, it is still clear that with increasing height, the width is also increasing, apparently to differing degrees in different species, but this hypothesis requires much more material to be tested. The number of ribs and epispires increases more or less constantly through ontogeny (Fig. 3B; r = 0.0695, R2 = 0.2213, p = 0.4809), namely from 7 to 10 in T. quadrifrons from a calyx height of around 4 to around 8 mm, and in T. rarus from 17 to 22 at heights from about 8 to 11.5 mm, although the new species has more ribs than representatives of the other species at comparable sizes. We have printed a linear trendline to these epispire row-data, although the distribution of data points vaguely suggest an exponential correlation; the number of specimens and thus data is too low to draw conclusions on the exponential increase in row number. Nevertheless, a nonlinear increase in epispire rows would not be surprising since the volume of a sphere (and the calyx of Tiaracrinus is nearly spherical) also increases exponentially when compared to diameter (calyx height) increase; an exponentially growing body would probably have an exponentially growing respiration, hence the possibly exponential increase in epispire rows. The variation in strength of the ribs and size of the epispires within one specimen appears to be low (compare Hauser 2008: pl. 1).

    Phylogeny

    Some of the relationships within the genus are undoubtedly as proposed by Le Menn (1990). Accordingly, T. oehlerti and T. moravicus with their elongate and slightly ornamented calices represent a small monophylum (supported by the results of our cluster analysis in Fig. 5). Intrageneric variability is dominated by the significant ontogenetic increase in the number of epispire rows. A possible correlation between calyx width and height through ontogeny lacks statistical support, which is probably due to the low amount of data. Alternatively, as proposed by Hauser (2008: 2), T. oehlerti and T. moravicus could be conspecific and were assigned to different species because of differences in preservation. The same question is open with respect to T. tedraedra and T. quadrifrons, two superficially similar species with profoundly different preservation (Hauser 2008: 5), which also form one cluster. T. jeanlemenni, T. rarus, T. tedraedra, and T. quadrifrons share the broader calyx with the narrower radial channels and might thus be closely related (see Fig. 3).

    Fig. 6.

    Reconstruction of the phylogeny of the species of Tiaracrinus, based on their morphology and stratigraphic occurrences. Devonian timescale after Kaufmann (2006). All ranges of species lack precision and are thus indicated by open boxes.

    f06_135.jpg

    The question arises, which of the various kinds of morphology represents the more plesiomorphic state. The age (Pragian to earliest Eifelian) of most of the reasonably well-known species does not differ significantly. Since T. oehlerti appears to be the oldest of the better known species, we suggest that the morphology with the elongate calyx and the more ornamented radial channels represent the more ancestral morphology (Fig. 6). At least the calyx shape is more similar to the genus Zophocrinus, which is one of the few genera in the same family according to the crinoid Treatise (Moore et al. 1978). Remarkably, all the other genera assigned to the Zophocrinidae lack epispires. Following Guensburg and Sprinkle (2007: 287), the presence of epispires in crinoids can be considered as a plesiomorphic character and thus, the morphology of Zophocrinus and Parazophocrinus would be more derived, if we accept the taxonomy of Moore et al. (1978). By contrast, it could be argued that the Tiaracrinus-lineage had evolved convergently, an assumption, which is less parsimonious. For a test of this latter hypothesis, material and data are not available at this point. Such material would have to show a transition between the epispire-free Zophocrinus and early Tiaracrinus with epispires, for instance with a very low number of rows.

    Conclusions

    Based on the higher number of ribs in the rhomboid rib-fields and the globular calyx-shape, we describe the new species Tiaracrinus jeanlemenni sp. nov., which resembles the Czech species T. rarus. The species pair T. jeanlemenni sp. nov. and T. rarus differs from the other Tiaracrinus species in the greater number of more narrow epispire rows and from the pair T. oehlerti and T. moravicus in the more globular calyx with the more narrow radial channels. Morphometric analyses (PCA and Cluster Analyses) support the closer relationships between the species pairs Tiaracrinus jeanlemenni sp. nov. and T. rarus, between T. tedraedra and T. quadrifrons, as well as between T. oehlerti and T. moravicus. In the cases of the latter two pairs, two explanations are at hand: Either, (i) T. tetraedra and T. moravicus represent junior synonyms with the type materials of both species-pairs being differently preserved or (ii) all four species, are closely related to the respective other species of the two species-pairs, representing two two-species monophyla. Based on their younger age and the much higher than wide calyx (reminiscent of the outgroup-genus Zophocrinus), we interpret the species-pair T. oehlerti and T. moravicus as the most plesiomorphic one within the genus, from which the other four species are derived.

    Acknowledgements

    The Moroccan colleagues of the Ministère de l'Energie et des Mines (Rabat and Midelt) benignly provided permits for the field work and for the export of samples. We greatly appreciate the work of the reviewers Elise Nardin (University of Toulouse, Toulouse, France) and Gary D. Webster (Washington State University, Pullman, USA), who put an unusual effort into their highly detailed reviews, thereby improving the manuscript significantly. We thank the Swiss National Science foundation for financial support of the field work (Project numbers 200021-1139564, 200020-25029, and 200020-132870).

    References

    1.

    SA. Aitken , J.C. Colom , C.M. Henderson , and PA. Johnston 2002. Stratigraphy, paleoecology, and origin of Lower Devonian (Emsian) carbonate mud buildups, Hamar Laghdad, eastern Anti-Atlas, Morocco, Africa. Bulletin of Canadian Petroleum Geology 50: 217–243. Google Scholar

    2.

    G.K.B. Alberti 1969. Trilobiten des jüngeren Siluriums sowie des Unterund Miteldevons. I. Mit Beiträgen zur Silur-Devon - Stratigraphie einiger Gebiete Marokkos und Oberfrankens. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft 520: 1–692. Google Scholar

    3.

    G.K.B. Alberti 1982. Der Hamar Laghdad (Tafilalt, SE Marokko), eine bedeutende Fundstelle devonischer Trilobiten. Natur & Museum 112: 172–182. Google Scholar

    4.

    J. Barrande 1887. Système Silurien du centre de la Bohéme. I: Recherches paléontologiques, Classe des Echinodermes, Sec. 1: Ordre des Cystidées 7. 233 pp. Published by the author, Praha. Google Scholar

    5.

    R.S. Bassler 1938. Pelmatozoa Paleozoica. In : W. Quenstedt (ed.), Fossilium catalogus, I(83): Animalia. 194 pp. W. Junk, Gravenhage. Google Scholar

    6.

    F.A. Bather 1900. The Pelmatozoa—Cystidea. In : E.R. Lankester (ed.), A Treatise on Zoology, 3: Echinodeimata , 38–77. A. & C. Black, London. Google Scholar

    7.

    F.A. Bather 1915, 1916. Studies in Edrioasteroidea. VI. Pyrgocystis n. g. Geological Magazine, new series 6 (2): 5–12, 49–60. Google Scholar

    8.

    Z. Belka 1994. Dewońskie budowle węglanowe (Carbonate buildups) Sahary Środkowej i ich związek z podmorskimi źródlami termalnymi (Carbonate mud buildups in the Devonian of the Central Sahara: evidences for submarine hydrothermal venting). Przegląd Geologiczny 5: 341–346. Google Scholar

    9.

    Z. Belka 1998. Early Devonain Kess-Kess carbonate mud mounds of the eastern Anti-Atlas (Morocco), and their relation to submarine hydrothermal venting. Journal of Sedimentary Research 68: 368–377. Google Scholar

    10.

    Z. Belka and B. Berkowski 2005. Discovery of thermophilic corals in an ancient hydrothermal vent community, Devonian, Morocco. Acta Geologica Polonica 55: 1–7. Google Scholar

    11.

    B. Berkowski 2004. Monospecific rugosan assemblage from the Emsian hydrothermal vents of Morocco. Acta Palaeontologica Polonica 49: 75–84. Google Scholar

    12.

    B. Berkowski 2006. Vent and mound rugose coral associations from the Middle Devonian of Hamar Laghdad (Anti-Atlas, Morocco). Geobios 39:155–170. Google Scholar

    13.

    B. Berkowski 2008. Emsian deep-water Rugosa assemblages of Hamar Laghdad (Devonian, Anti-Atlas, Morocco). Palaeontographica 284: 17–68. Google Scholar

    14.

    B. Berkowski 2012. Life strategies and function of dissepiments in rugose coral Catactotoechus instabilis from the Lower Devonian of Morocco. Acta Palaeontologica Polonica 57: 391–400. Google Scholar

    15.

    B Berkowski and C. Klug 2012. Lucky rugose corals on crinoid stems: unusual examples of subepidermal epizoans from the Devonian of Morocco. Lethaia 45: 24–33. Google Scholar

    16.

    J. Bohatý 2011 Revision of the flexible crinoid genus Ammonicrinus and a new hypothesis on its life mode. Acta Palaeontologica Polonica 56: 615–639. Google Scholar

    17.

    T. Brachert , W. Buggisch , E. Flügel , H. Hüssner , M.M. Joachimski , and F. Tourneur 1992. Controls of mud mound formation: the Early Devonian Kess-Kess carbonates of the Hamar Laghdad, Antiatlas, Morocco. Geologische Rundschau 81: 15–44. Google Scholar

    18.

    P. Bultynck and O.H. Walliser 2000. Emsian to Middle Frasnian sections in the northern Tafilalt. In : A. El Hassani and A. Tahiri (eds.), Moroccan meeting of the Subcommision on Devonian Stratigraphy (SDS)-IGCP 421 Excursion Guidebook. Notes et Mémoires du Service Géologique du Maroc 399: 11–20. Google Scholar

    19.

    B. Cavalazzi , R. Barbieri , and G.G. Ori 2007. Chemosynthetic microbialites in the Devonian carbonate mounds of Hamar Laghdad (Anti-Atlas, Morocco). Sedimentary Geology 200: 73–88. Google Scholar

    20.

    K. De Baets , C. Klug , and Y. Plusquellec 2010. Zlíchovian faunas with early ammonoids from Morocco and their use for the correlation between the eastern Anti-Atlas and the western Dra Valley. Bulletin of Geosciences 85: 317–352. Google Scholar

    21.

    K. De Baets , C. Klug , and D. Korn 2011. Devonian pearls and ammonoidendoparasite coevolution. Acta Palaeontologica Polonica 56: 159–180. Google Scholar

    22.

    R. Dehm 1934. Untersuchungen an Cystoideen aus dem rheinischen Unterdevon. Sitzungsberichte der bayerischen Akademie der Wissenschaften mathematisch-naturwissenschaftliche Abteilung (München) 1934: 19–3. Google Scholar

    23.

    R. Dehm 1961. Über Pyrgocystis (Rhenopyrgus nov. subgen.) coronaeformis Rievers aus dem rheinischen Unter-Devon. Mitteilungen der bayerischen Staatssammlung für Paläontologie und historische Geologie (München) 1: 13–17. Google Scholar

    24.

    S. Döring 2002. Sedimentological evolution of the late Emsian to early Givetian carbonate ramp in the Mader (eastern Anti-Atlas, SE-Morocco). 116 pp. Unpublished Ph.D. thesis, Tübingen,  http://tobias-lib.uni-tuebingen.de/volltexte/2002/560/. Google Scholar

    25.

    M. Foote 1995. Morphological diversification of Paleozoic crinoids. Paleobiology 21: 273–299. Google Scholar

    26.

    M. Foote 1999. Morphological diversity in the evolutionary radiation of Paleozoic and post-Paleozoic crinoids. Paleobiology 25 (Supplement): 1–115. Google Scholar

    27.

    F. Frech 1902. Lethaea Geognostica oder Beschreibung und Abbildung der für die Gebirgs-Foimationen bezeichnendsten Versteinerungen. I. Theil: Lethaea palaeozoica & Tab; Echinodermen , 144–146. Schweizerbart, Stuttgart. Google Scholar

    28.

    T.E. Guensburg and J. Sprinkle 2007. Phylogenetic implications of the Protocrinoida: Blastozoans are not ancestral to crinoids. Annales de Paléontologie 93: 277–290. Google Scholar

    29.

    Ø. Hammer , D.A.T. Harper , and P.D. Ryan 2001. PAST: Palaeontological statistics software package for education and data analysis. Palaeontologia Electronica 4(1): 1–9. Google Scholar

    30.

    R. Haude 1993. Limbrachoide, ungewöhnliche Arme der bisher “armlosen” exotischen Seelilie Tiaracrinus (Devon; Rheinisches Schiefergebirge). Göttinger Arbeiten Geologie und Paläontologie 58: 87–96. Google Scholar

    31.

    J. Hauser 1997. Die Crinoiden des Mitteldevon der Eifler Kalkmulden. 274 pp. Published by the author, Bonn. Google Scholar

    32.

    J. Hauser 2008. Revision von Tiaracrinus (Crinoidea, Cladida) aus dem Paläozoikum der Eifel und dem Sauerland (Rheinisches Schiefergebirge), Massiv Armoricain (Frankreich), Böhmen (Tschechien) und Nord-Afrika (Algerien), 1–8. Published by the author, Bonn. Google Scholar

    33.

    H. Hollard 1974. Recherches sur la stratigraphie des formations du Dévonien moyen, de l'Emsien supérieur au Frasnien, dans le Sud du Tafilalt et dans le Ma'der (Anti-Atlas oriental). Notes et Mémoires du Service Géologique du Maroc 264: 7–68. Google Scholar

    34.

    D.J. Holloway and P.A. Jell 1983. Silurian and Devonian edrioasteroids from Australia. Journal of Paleontology 57: 1001–1016. Google Scholar

    35.

    O. Jaekel 1899. Referat über: Ch. Wachsmuth & Fr. Springer: The North American Crinoidea Camerata. Neues Jahrbuch für Geologie und Paläontologie 1899: 374–383. Google Scholar

    36.

    O. Jaekel 1901. Tiaracrinus tedraedra n. sp. In : H. Lotz (ed.), Pentamerus-Quarzit und Greifensteiner Kalk. Jahrbuch Königlich Preussischer geologischer Landesanstalten 21: 77. Google Scholar

    37.

    O. Jaekel 1918. Phylogenie und system der Pelmatozoen. Paläontologische Zeitschrift 1: 1–28. Google Scholar

    38.

    B. Kaufmann 1998. Facies, stratigraphy and diagenesis of Middle Devonian reef- and mud-mounds in the Mader (eastern Anti-Atlas, Morocco). Acta Geologica Polonica 48: 43–106. Google Scholar

    39.

    B. Kaufmann 2006. Calibrating the Devonian Time Scale: A synthesis of U-Pb ID-TIMS ages and conodont stratigraphy. Earth Science Reviews 76: 175–190. Google Scholar

    40.

    T. Klein 1754. Ordre naturel des oursins de mer et fossiles, avec des observations sur les piquants des oursins de mer et quelques remarques sur les bélemnites. 235 pp. C.J.B. Bauche, Paris. Google Scholar

    41.

    C. Klug 2001. Life-cycles of Emsian and Eifelian ammonoids (Devonian). Lethaia 34: 215–233. Google Scholar

    42.

    C. Klug 2002. Quantitative stratigraphy and taxonomy of late Emsian and Eifelian ammonoids of the eastern Anti-Atlas (Morocco). Courier Forschungsinstitut Senckenberg , 238: 1–109. Google Scholar

    43.

    C. Klug , B. Kröger , M. Rücklin , D. Korn , M. Schemm-Gregory , K. De Baets , and R.H. Mapes 2008. Ecological change during the early Emsian (Devonian) in the Tafilalt (Morocco), the origin of the Ammonoidea, and the first African pyrgocystid edrioasteroids, machaerids and phyllocarids. Palaeontographica A 283 (1,2 Lfg.): 1–94. Google Scholar

    44.

    C. Klug , H. Schulz , and K. De Baets 2009. Red trilobites with green eyes from the Early Devonian of the Tafilalt (Morocco). Acta Palaeontologica Polonica 54:117–123. Google Scholar

    45.

    J. Kříž 1992. Silurian field excursions: Prague Basin (Barrandian), Bohemia. National Museum of Wales, Geological Series 13: 1–111. Google Scholar

    46.

    D. Le Maître 1958a. Contributions à l'étude des faunes dévoniennes d'Afrique du Nord, 1: Echinodermes. Bulletin du Service de la Carte Géologique de l'Algérie (n. s.) 20: 113–154. Google Scholar

    47.

    D. Le Maître 1958b. Crinoïdes du Dévonien d'Afrique du Nord. Comptes Rendus sommaires Société Géologique de France 14: 344–346. Google Scholar

    48.

    D. Le Maître 1958c. Le genre Tiaracrinus Schultze. Comptes Rendus de l'Académie des Sciences Paris 246: 1068–1071. Google Scholar

    49.

    J. Le Menn 1987. Nouveaux échinodermes des schistes et calcaires du Dévonien inférieur du Basin de Laval (Massif Armoricain, France. Geobios 20: 215–235. Google Scholar

    50.

    J. Le Menn 1990. Les calices du genre Tiaracrinus (Crinoidea, Inadunata) dans l'Emsien d'Algérie et du Massif Armoricain. Geobios 23: 161–167. Google Scholar

    51.

    H. Lotz 1901. Pentamerus-Quarzit und Greifensteiner Kalk. Jahrbuch Königlich Preussischer geologischer Landesanstalten 21: 64–80. Google Scholar

    52.

    D. Massa , A. Combaz , and G. Manderscheid 1965. Observations sur les séries Siluro-Dévoniennes des confins Algéro-Marocains du Sud. Notes et Mémoires, Compagnie Française des Pétroles 8: 1–187. Google Scholar

    53.

    J.S. Miller 1821. A natural history of the Crinoidea or lily-shaped animals, with observation on the genera Astria, Euryale, Comatula, and Marsupites. 150 pp. Bryan & Co, Bristol. Google Scholar

    54.

    S.A. Miller 1883. The American Palaeozoic Fossils. A Catalogue of the Genera and Species, with Names of Authors, Dates, Places of Publication, Groups of Books in which Found, and the Etymology and Signification of the Words, and an Introduction Devoted to the Stratigraphical Geology of the Palaeozoic Rocks: Echinodermata, 2. Edition , 247–334. Privately published, Cincinnati. Google Scholar

    55.

    S.A. Miller 1891. The structure, classification and arrangement of American Palaeozoic crinoids into families. Indiana Department of Geology & Natural History, 16th Annual Report (for 1888, 1889): 302–326. Google Scholar

    56.

    S.A. Miller 1892. North American Geology and Palaeontology. First Appendix , 665–718. Western Methodist Book Concern, Cincinnati. Google Scholar

    57.

    R.C. Moore and L.R. Laudon 1943. Evolution and classification of Paleozoic crinoids. Geological Society of America, Special Papers 46: 1–153. Google Scholar

    58.

    R.C. Moore , N.G. Lane , H.L. Strimple , and J. Sprinkle 1978. Order Disparida. In : R.C. Moore and C. Teichert (ed.), Treatise on Invertebrate Paleontology, Part T: Echinodermata 2, T520–T564. Geologial Society of America and University of Kansas, Boulder, Lawrence. Google Scholar

    59.

    R. Prokop 1987. The stratigraphical distribution of Devonian crinoids in the Barrandian area (Czechoslovakia). Newsletter on Stratigraphy 17 (2): 101–107. Google Scholar

    60.

    R.J. Prokop and V. Petr 2002. Survey of echinoderms and a new ophiocistioid Branzoviella talpa gen. et sp. n. (Echinodermata, Ophiocistioidea) in the Lower Devonian, Lochkov Formation of the Barrandian area, Czech Republic. Bulletin of the Czech Geological Survey 77: 237–240. Google Scholar

    61.

    I.A. Rahman and H. Lintz 2012. Dehmicystis globulus, an enigmatic solute (Echinodermata) from the Lower Devonian Hunsrück Slate. Paläontologische Zeitschrift 86: 59–70. Google Scholar

    62.

    E. Roch 1934. Sur des phénomènes remarquables observés dans la région d'Erfoud (confins algéro-marocains du Sud). Association Etudes de la Géologie Méditerranéenne Occidentale 5: 1–10. Google Scholar

    63.

    C. Schlüter 1881. Bau der Gattung Tiaracrinus. Sitzungsberichte der niederrheinischen Gesellschaft in Bonn am 8. Juni 1881 Bonn , 210–212. Niederrheinische Gesellschaft, Bonn. Google Scholar

    64.

    W.E. Schmidt 1934. Die Crinoiden des rheinischen Devons, I. Teil: Die Crinoiden des Hunsrückschiefers. Abhandlungen der preussischen geologischen Landesanstalt (Berlin), Neue Folge 163: 1–149. Google Scholar

    65.

    L. Schultze 1866. Monographie der Echinodermen des Eifler-Kalkes. Denkschrift Königlichen Akademie der Wissenschaften, mathematischnaturwissenschaftlichen Classe 26: 113–230. Google Scholar

    66.

    F. Springer 1926. American Silurian crinoids. Smithsonian Institute Publication 2871: 1–239. Google Scholar

    67.

    C.D. Sumrall and G.A. Wray 2007. Ontogeny in the fossil record: diversification of body plans and the evolution of “aberrant” symmetry in Paleozoic Echinoderms. Paleobiology 33: 149–163. Google Scholar

    68.

    R. Töneböhn 1991. Bildungsbedingungen epikontinentaler Cephalopodenkalke (Devon, SE-Marokko). Göttinger Arbeiten zur Geologie und Paläontologie 47: 1–114. Google Scholar

    69.

    G. Ubaghs and B. Bouček 1962. Sur la présence du genre Tiaracrinus Schultze (Crinoidea) dans le Dévonien inférieur de Moravie (Tiaracrinus moravicus n. sp.). Sborník Ustředního ústavu geologického (Oddil paleontologický) 27: 41–50. Google Scholar

    70.

    J. Wendt 1993. Steep-sided carbonate mud mounds in the Middle Devonian of the eastern Anti-Atlas, Morocco. Geological Magazine 130: 69–83. Google Scholar
    © 2014 C. Klug et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
    Christian Klug, Kenneth De Baets, Carole June Naglik, and Johnny Waters "A New Species of Tiaracrinus from the Latest Emsian of Morocco and Its Phylogeny," Acta Palaeontologica Polonica 59(1), 135-145, (6 June 2012). https://doi.org/10.4202/app.2011.0188
    Received: 30 November 2011; Accepted: 4 June 2012; Published: 6 June 2012
    JOURNAL ARTICLE
    11 PAGES


    SHARE
    ARTICLE IMPACT
    Back to Top