Redescription of the Cyathocrinid Cladid Codiacrinus Schultzei Follmann, 1887 from the Lower Devonian Hunsru¨Ck Slate at Bundenbach (Germany)
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Pala¨ontol Z (2011) 85:241–255 DOI 10.1007/s12542-010-0089-2 RESEARCH PAPER Redescription of the cyathocrinid cladid Codiacrinus schultzei Follmann, 1887 from the Lower Devonian Hunsru¨ck Slate at Bundenbach (Germany) Wouter H. Su¨dkamp Received: 19 April 2010 / Accepted: 25 October 2010 / Published online: 24 November 2010 Ó Springer-Verlag 2010 Abstract Codiacrinus schultzei Follmann, 1887 com- zeigt mo¨glicherweise den mittleren und hinteren Darmtrakt monly occurs in the Lower Devonian Hunsru¨ck Slate of (Weichteilerhaltung). Auch die Form und Anordnung der Bundenbach (Germany). Although this cyathocrinid cladid Deckplatten sind detaillierter als vorher beschrieben wor- has been studied for almost 125 years, its morphology den. Codiacrinus schultzei ist u¨berarbeitet worden und wird remains incompletely known. This article reports unusual mit den anderen Arten innerhalb der Gattung verglichen. arm growth, the regeneration of an arm, the preservation of Weitere Betrachtungen der taxonomischen Zugeho¨rigkeit tegminal plates, the sculpture of the cup (hexagonal con- (innerhalb der Flexibilia?) sind angebracht. centric lines), and the preservation of visceral organs, which were positioned within the cup. One X-radiograph Schlu¨sselwo¨rter Crinoidea Á Codiacrinus Á Elicrinus Á possibly shows the mid- and hind-gut (preserved as soft Deckplatten Á Weichteilerhaltung Á Taxonomische tissues). Furthermore, the shape and arrangement of the zuordnung Á Hunsru¨ckschiefer Á Unter-Devon cover plates are described in more detail than previously. Codiacrinus schultzei is systematically redescribed and compared with the other species in the genus. Further study Introduction of the systematic placement (within the Flexibilia?) is appropriate. The cyathocrinid cladid Codiacrinus schultzei Follmann, 1887 is a common crinoid in the Lower Devonian Keywords Crinoidea Á Codiacrinus Á Elicrinus Á Cover Hunsru¨ck Slate, restricted to horizons of the conservation plates Á Soft-tissue preservation Á Systematic position Á lagersta¨tte around Bundenbach and Gemu¨nden (Germany). Hunsru¨ck Slate Á Lower Devonian There are over 100 specimens in the collections of the Museum fu¨r Naturkunde, Berlin, which represents about Kurzfassung Codiacrinus schultzei Follmann, 1887 ist 14% of the (prepared) crinoids that are stored from the im unterdevonischen Hunsru¨ckschiefer von Bundenbach Hunsru¨ck region (Su¨dkamp 1995: 120). (Deutschland) relativ ha¨ufig. Obwohl dieser Cyathocrinoide This material is important for discussions of crinoid (Unterklasse Cladida) seit fast 125 Jahren belegt ist, ist morphology, as individuals from Bundenbach are typically seine Morphologie nicht vollsta¨ndig bekannt. Dieser Artikel preserved complete; Codiacrinus species from other parts berichtet u¨ber ungewo¨hnliches Armwachstum und die of the world are largely represented by cups only. Despite Regeneration eines Armes, u¨ber die Erhaltung der Platten two systematic descriptions in the 19th century, a treatment der Kelchdecke, u¨ber die Kelchstruktur (eckige konzentri- by Schmidt (1934), and the relative abundance of fossils, sche Linien) und den Erhalt der inneren Organe, die in der the morphology of C. schultzei is not completely known to Kelchkapsel untergebracht waren. Eines der Ro¨ntgenbilder date, as this contribution shows. One of the reasons for this is that in the 19th century the fossils were not prepared and X-rayed. Today, preparation W. H. Su¨dkamp (&) Gartenstraße 11, 55626 Bundenbach, Germany starts after an X-radiograph has been taken, which can help e-mail: [email protected] to detect the extent and inner structures of the fossil. This 123 242 W. H. Su¨dkamp allows a skilled preparator to expose the deeper parts of the (1895), and Schmidt (1934) noted that the cup plates are fossil without damaging surface details. A further com- smooth. Indeed, almost all cups are, but this is presumably plication when describing specimens is that the armtips are a diagenetic effect, as the thin cup plates of many speci- mostly enrolled (Fig. 1) or curved over the cup, which mens are broken and have cracks (Figs. 1, 4) that were obscures their total length and morphological features. secondarily filled with minerals such as quartzite. In this The original description of C. schultzei was based on contribution, the author reports the first cup with an orna- three specimens. One of these (Follmann 1887: pl. 3 fig. 1) mentation preserved. Secondary mineralization also has the infrabasal circlet exposed very clearly (due to occurred in the gaps where the brachials and especially the tectonic distortion). It is composed of one small and two (distal) columnals of the stem were separated diageneti- larger plates. Jaekel (1895: 63) observed up to five infra- cally; tectonic deformation can cause an increase in length basals in one specimen, which he did not figure, but this is of the stem of nearly 30% (Schmidt 1934: 72). most certainly incorrect. Possibly, Jaekel was confused by Due to the enrolled armtips, Follmann (1887) and Jaekel a crack in one of the infrabasal plates of Follmann’s (1895) did not recognize that the arms can be divided into specimen. Five infrabasals would also be inconsistent with more than two branches. Schmidt (1934: textfigs. 14b2–b3; the condition in other Codiacrinus species, all of which pl. 7 figs. 2a–b), however, discovered ‘‘feather- or comb- have three infrabasals. Schmidt (1934: 71) described three like’’ cover plates along the quartibrachs of Berlin speci- infrabasals for C. schultzei and argued that these can only men M.B.E318. The individuals reported herein allow a be seen when the lowermost part of the cup lies in an more comprehensive description of the shape and unnatural oblique position. Follmann (1887), Jaekel arrangement of these plates. Soft-tissue preservation The documented preservation of echinoderm soft tissues in the fossil record, including echinoderms from the Hunsru¨ck Slate, was summarized by Kammer and Ausich (2007) and Glass and Blake (2004). The first convincing soft-tissue preservation in crinoids is the uncalcified anal sac of the Mississippian cladid crinoid Tubulusocrinus doliolus from Scotland (Kammer and Ausich 2007). Soft-tissue pyritization is very rare and restricted to unusual diagenetic conditions. However, some horizons of the Hunsru¨ck Slate are well known for their rapid deposi- tion (which prevented the breakdown of carcasses) and special sediment chemistry (low concentrations of organic matter and unusually high concentrations of iron), which created the conditions necessary for pyritization of soft- bodied fossils (Briggs et al. 1996). A remarkable example of this is the preservation of tube feet through pyritization in the Hunsru¨ck Slate protasterid ophiuroid Bundenbachia beneckei (Glass and Blake 2004). The evidence for presence of nonmineralized tissue preservation in Hunsru¨ck Slate crinoids (e.g., definite tube feet and gonads) is questionable and requires further detailed documentation (Glass and Blake 2004: 76; Kam- mer and Ausich 2007: 957). Schmidt (1934: textfigs. 22a1, 25b1, 28c1; pl. 14 figs. 2a–b; pl. 18 fig. 2; and pl. 19 fig. 1) observed possible soft-tissue preservation in Imitatocrinus gracilior, Bathericrinus semipinnulatus, and Macarocrinus semelfurcatus. However, re-examination of one of the Fig. 1 Codiacrinus schultzei Follmann (1887). Typical specimen specimens by Otto (2000: 79) showed that the tentacle-like with cracks in the cup plates and enrolled tips of the arms. Below: a shell of a brachiopod or bivalve. Mu¨hlenberg quarry. M.B.E. 1479. structures that Schmidt (1934) described are formed by Collection Kutscher (1933). Width of cup = 30 mm sclerites, and thus are not soft parts. Glass and Blake (2004: 123 Redescription of the cyathocrinid cladid Codiacrinus schultzei Follmann, 1887 243 76) suggested that their sclerotized nature is indicative of Codiacrinus schultzei Follmann, 1887 pinnules. Bartels and Brassel (1990: fig. 34) figured an Figures 1, 2, 3, 4, 5, 6f, 7, 9, 10, 11, and 12 X-radiograph from W. Stu¨rmer of Codiacrinus schultzei. In the lower part of its cup white shadows can be recog- nized, and the authors interpreted these as representing * v 1887 Codiacrinus schultzei Follmann: 123, pl. 3 remnants of the gut. To test this interpretation, further figs. 1–1b X-radiographs are examined in this study. 1895 Codiacrinus schultzei Follmann.—Jaekel: 64 1897–1902 Codiacrinus schultzei Follmann.—Frech: Depository: M.B.E. = Museum fu¨r Naturkunde der 145, pl. 23b fig. 3 (cop. Follmann 1887) Humboldt-Universita¨t, Institut fu¨r Pala¨ontologie Berlin; 1930 Codiacrinus.—Opitz: pls. 5–7 THD = Nationaal Natuurhistorisch Museum ‘‘Naturalis’’ 1931 Codiacrinus schultzei Follmann.—Opitz: Leiden, The Netherlands; I.P.B. = Institut fu¨r Pala¨ontolo- pl. 4 gie, Rheinische Friedrich-Wilhelms-Universita¨t Bonn; 1932 Codiacrinus schultzei Follmann.—Opitz: H.M. = Hunsru¨ck-Museum Simmern. pls. 5–7; pl. 100 lt 1934 Codiacrinus schultzei Follmann.—Schmidt: 11, 71, 137, textfig. 14, pl. 7 figs. 1, 2; pl. 27 Systematic paleontology fig. 1 (cop. Opitz 1931) 1935 Codiacrinus schultzei Follmann.—Opitz: Symbols and abbreviations used in synonymy list are from fig. 4 Matthews (1973). Classification follows Bartels et al. 1943 Codiacrinus schultzei Follmann.—Bassler (1998a) and Simms and Sevastopulo (1993). and Moodey: 368 Class Crinoidea MILLER 1962 Codiacrinus schultzei.—Breimer: 160 Subclass Cladida MOORE &LAUDON 1978 Codiacrinus schultzei Follmann.—Fischer Infraclass Cyathocrinina BATHER and Gayrard-Valy: 101,