1150

J. Paleont., 82(6), 2008, pp. 1150–1160Copyright � 2008, The Paleontological Society0022-3360/08/0082-1150$03.00

VETUPRAECA N. GEN. AND MUCOPRAECA N. GEN.(CRYPTODONTA, BIVALVIA): A REAPPRAISAL OF LATE DEVONIAN

BIVALVES FROM THE HERCYNIAN FACIESJUDITH NAGEL-MYERS,1 MICHAEL R. W. AMLER,2 AND R. THOMAS BECKER3

1 Paleontological Research Institution, Cornell University, 1259 Trumansburg Rd., Ithaca, New York 14850, �jn226@cornell.edu�;2LMU Munchen, Department f. Geo- und Umweltwissenschaften, Sektion Palaontologie, Richard Wagner-Strasse 10, 80333 Munchen, Germany; and

3Westfalische Wilhelms-Universitat Munster, Geologisch-Palaontologisches Institut Munster, Correns str. 24, 48149 Munster, Germany

ABSTRACT—Bivalves from the Late Devonian pelagic or Hercynian Facies of classical regions such as eastern North America and Europe havenot been investigated for almost a century.

A group of small, radially ribbed bivalves frequently occurs in association with ammonoids and conodonts in pelagic cephalopod limestonesand shales of the latest Frasnian and early Famennian. These bivalves have traditionally been assigned to the Late Silurian genus PraecardiumBarrande, 1881. Re-studying the types of the Late Devonian taxa, Cardium? vetustum Hall, 1843, Cardiola duplicata Munster, 1840, Praecar-dium clymeniae Beushausen, 1895, Praecardium melletes Clarke, 1904, and Praecardium multicostatum Clarke, 1904 shows that they differsignificantly from Praecardium.

As a result, two new genera, Vetupraeca n. gen. and Mucopraeca n. gen, are established. Furthermore, neotypes are designated for Cardiolanehdensis, Kayser, 1873 and Vetupraeca clymeniae (Beushausen, 1895), and lectotypes are chosen for Mucopraeca multicostata (Clarke, 1904)and Vetupraeca duplicata (Munster, 1840). These bivalve taxa were widely distributed in the subtropical to tropical, latest Frasnian/earlyFamennian outer shelf habitats of Laurussia and Gondwana.

INTRODUCTION

DESPITE THEIR abundance in the fossil record, little has beenadded to our knowledge of Late Devonian bivalves from

the Hercynian Facies since the beginning of the twentieth century.Due to their uncertain systematic position, they appear in faunallists as ‘‘Lamellibranchiata div.’’ or are placed within poorly de-fined morphologic groups. Lack of modern studies and taxonomicrevisions has hindered any understanding of the evolutionary his-tory and biostratigraphy of these bivalves, which lived in ecosys-tems recurrently affected by environmental changes, especiallythose associated with extinction events, on various scales (e.g.,House, 1985, 2002; Walliser, 1985; Becker, 1993). Our ongoingstudy of the Hercynian bivalve fauna is revising the taxonomy ofpoorly understood genera, such as Loxopteria, Elasmatium, Lu-nulacardium, and Prosochasma. Furthermore, initial biostrati-graphic and paleoecologic information on these taxa is compiled(e.g. Nagel-Myers and Amler, 2007).

This paper focuses on a group of radially ribbed bivalves thatfrequently occur in Late Devonian pelagic faunas; these taxa areplaced in Vetupraeca n. gen. and Mucopraeca n. gen. The LateDevonian pelagic facies is known as the Hercynian Facies. Itincludes mostly carbonates and fine-grained siliciclastic sedimentsthat were deposited on the outer shelf south of the Old Red Con-tinent (i.e., Laurussia; Fig. 1). These deposits accumulated belowthe photic zone and often represent poorly oxygenated environ-ments (Erben, 1964). The Hercynian Facies or pelagic facies ischaracterized by a fauna dominated mostly by pelagic organismsas e.g., goniatites, conodonts, and tentaculites. Together with adistinct faunal suite of gastropods, solitary rugose corals, bra-chiopods, crinoids, and trilobites, the Hercynian bivalves werepart of a characteristic, low diversity, deeper-water benthos.

The Late Silurian and Early Devonian Bohemian Facies of thePrague Basin (Czech Republic) is the older equivalent of the LateDevonian Hercynian Facies of Central Europe. Therefore, manyLate Devonian bivalve species have been placed within generaoriginally described from Bohemia by Barrande (1881). The LateDevonian taxa studied herein were previously assigned to the Bo-hemian genus Praecardium Barrande, 1881. After restudying thediagnosis of Praecardium, it became obvious that morphologi-cally, these radially ribbed bivalves from the Late Devonian couldno longer be included in this genus. Currently, five species arethought to be constituents of the Late Devonian pelagic facies:Vetupraeca vetusta, Vetupraeca duplicata, Vetupraeca melletes,Vetupraeca clymeniae, and Mucopraeca multicostatum.

LOCALITIES

Based on existing data, these genera appear to be restricted tothe latest Frasnian/early Famennian. They have been recordedfrom several German regions, including the Rhenish Massif, Her-cynian Mountains, Thuringia, Saxony, and the Franconian Forest.They also occur in the Devonian of southern Morocco, France(Armorican Massif, Montagne Noire), Poland (Holy Cross Moun-tains), and in western New York State. Coeval bivalve faunasfrom Russia, Iran, China, and Australia are poorly known, buttheir pelagic molluscan assemblages are rather similar to thosefrom the classical localities.

The northern and northeastern portion of the Rhenish Massifpossesses abundant Late Devonian outcrops. Examined materialfrom this area includes specimens from Bergisch Gladbach (west-ern Rhenish Massif, Paffrath Syncline), Eskesberg (northernRhenish Massif), Nehden-Schurbusch (northeastern Rhenish Mas-sif), and Enkeberg (northeastern Rhenish Massif). Some studiedspecimens are from Gattendorf in the Franconian Forest (south-eastern Germany).

Material from France was collected at Col de Pueche de laSuque (Montagne Noire, Armorican Massif), Mentaresses (Mon-tagne Noire, Armorican Massif), and Combe de Izarne (MontagneNoire, Armorican Massif), while the examined type material fromNorth America is from Walnut Creek, Forestville, and Correll’sPoint, all from the Chautauqua province in western New YorkState.

The Late Devonian biostratigraphy and its international bio-zonation key (Fig. 4) used here is based on the global ammonoidzonation outlined by Becker et al. (2004).

MATERIAL AND PRESERVATION

The fossil material examined in this study is housed primarilyin the Museum fur Naturkunde, Berlin, and comprises Devonianbivalve specimens from various German regions. These speci-mens have been collected over a period of 150 years in the courseof preparation of the first geological maps of the Rhenish Massif.Furthermore, they include types described in several monographsconcerning the German Devonian, especially those of Beushau-sen’s (1895) unique record of Devonian bivalves. In addition tothis extensive collection, original material from the BayerischeStaatssammlung (Munich), the National Museum (Prague), theNew York State Museum (Albany), and the American Museumof Natural History (New York) has been examined.

The state of preservation is one of the most significant, but

1151NAGEL-MYERS ET AL.—DEVONIAN BIVALVES FROM HERCYNIAN FACIES

FIGURE 1—Paleogeographic distribution of investigated taxa occurrences (paleogeographic map based on Golonka, 2000); 1, New York State, USA; 2,Meseta, Morocco; 3, Tafilalt and Maider, Morocco; 4, Armorican Massif, France; 5, Franconian Forest, Germany; 6, Rhenish Massif, Germany; 7, HercynianMountains, Germany; 8, Holy Cross Mountains, Poland.

FIGURE 2—1–8, Praecardium primulum, 1–3, original figure of topotype NMP L23344; 4–5, topotype NMP L23344; 6–7, original figure of lectotype NMPL 20361 (Barrande, 1881, Pl. 96, I, Figs. 1–2); 8, topotype NMP L20363.1.

often neglected, aspects in the study of pre-Carboniferous bi-valves (McAlester, 1962b; Amler, 1995). Due to the differentialpreservation of individuals, morphological features of species canappear to vary considerably (e.g., Rogalla and Amler, 2003). Thishas led to significant taxonomic and morphological confusion inthe past. The studied specimens show rather different modes ofpreservation; specimens occur as internal, external, or composite

molds. Original shell material is rarely preserved and many spec-imens are steinkerns. The pyritic steinkerns from the Knoppen-bissen Formation are preservationally unique; they display manydetails of the some specimens’ inner shell surface. In some rarecases the preservation of soft-tissue attachment structures pre-served as black marks on the pyritic steinkern of ammonoids andbivalves has been reported (Richter, 2002). This form of soft-body

1152 JOURNAL OF PALEONTOLOGY, V. 82, NO. 6, 2008

preservation is the result of rapid pyritization of the steinkern,before the shell is compromised by dissolution (Berner, 1984;Richter, 2002). Thus, these specimens are true steinkerns, dis-playing the inner surface of shells that have not been compro-mised by the dissolution of shell layers, as has been reported formany other other bivalve taxa (Crampton, 2004; Johnston andCollom, 1998)

SYSTEMATICS

One of the fundamental problems in Paleozoic bivalve system-atics is that new genera and species were proposed in studies oflocal faunas, usually within a single geologic interval. This cre-ated numerous synonyms for these rather slowly evolving bi-valves throughout their stratigraphic range. McAlester (1962a)observed this phenomenon in his study of the Late Devonian Che-mung fauna of New York State, and not much has changed since.On the other hand, it is unlikely that bivalves survived withoutevolutionary change through the complex sequence of global ex-tinction events and ecological crises, which are known to haveaffected other marine benthic groups. However, the outdated stateof knowledge does not provide an adequate database for an in-terpretation of the evolutionary pathways of praecardiid bivalves.

As mentioned above, the systematic designations of these taxaare currently rather confused and lack well-defined type speciesand type genera. Therefore, the classification of taxa within thehigher categories of the Cryptodonta is tentatively revised hereinand follows Amler (1999, p. 246). The long-abandoned subclassCryptodonta was resurrected by Johnston and Collom (1998). Itsrelationships and position within the higher bivalve classificationis uncertain to an extent, but it is the most adequate classificationavailable for these taxa.

All figured specimens have been whitened with ammoniumchloride. The following abbreviations are used in this study forthe repository of discussed specimens and collections: NYSM,New York State Museum, Albany; AMNH, American Museumof Natural History, New York; MB.M, Museum fur Naturkunde,Berlin; NMP, National Museum, Praha; GZG, Geowissenschaf-tliches Zentrum der Universitat Gottingen; BSPG, BayerischeStaatssammlung fur Palaontologie und Geologie, Munchen; andB6A-35, Collection of the Westfalische-Wilhelms-UniversitatMunster.

Class BIVALVIA Linnaeus, 1758Subclass CRYPTODONTA Neumayr, 1884

Order PRAECARDIOIDA Newell, 1965Family PRAECARDIIDAE Hoernes, 1884

Genus VETUPRAECA new genusType species.⎯Cardium? vetustum Hall, 1843.Included species.⎯Cardium? vetustum Hall, Praecardium mel-

letes Clarke, Cardiola duplicata Munster, Praecardium clymeniaeBeushausen.

Diagnosis.⎯Shells trigonal to subtrigonal, equivalved. Valveshighly inequilateral, prosocline; umbos prosogyrate, terminal, sit-uated anterior, projecting slightly over hinge line. Broad, flat, ra-dial ribs, often with shallow groove in the middle; fine, commar-ginal striae. At posterior margin ribs more closely spaced, finer,sometimes more rounded, less distinct in outline. Radial ribs al-most parallel with dorsal margin on posterior part of shell; onanterior part ribs shorter, perpendicular to commissure; ribs broad-en distinctly at margin. Internal features unknown.

Etymology.⎯Anagram of the first syllables of the species ‘‘vetustum’’ andthe genus ‘‘Praecardium.’’

Occurrence.⎯Vetupraeca n. gen. is described from various localities ofthe early Famennian (Nehdenian, UD II-B/E). Its first appearance is reportedfrom the Upper Kellwasser beds of Mont Peyroux and Coumiac (ArmoricanMassif, southern France; Becker and House, 1994). Furthermore, Kriz (2004)described specimens that are now placed within Vetupraeca from La Serreand Comb d’Izarne of latest Frasnian age of the same area. Its currentlyknown geographic distribution extends from New York State to the Rhenish

Massif, Franconian Forest, the Holy Cross Mountains, the Montagne Noire,and southern Morocco. It is likely that further occurrences will be discoveredonce more attention is paid to bivalves of the pelagic facies.

Discussion.⎯The Late Devonian species included in Vetuprae-ca n. gen. have traditionally been assigned to Praecardium Bar-rande, 1881, with its type species Praecardium primulum Barran-de (Ruzicka and Prantl, 1960). The latter occurs in the LateSilurian Bohemian Facies, where it is represented by 45 as yetunrevised species. However, the Late Devonian genus Vetupraecadiffers distinctly from this Late Silurian taxon. It is clearly tri-gonal in outline, all included taxa are markedly prosocline, andthe maximum shell growth occurs on the posterior part of thevalves at the transition from the posterior to the ventral margin.Praecardium is subcircular in outline and only slightly inequila-teral. The zone of greatest shell growth is located in the middleof the ventral margin, which makes the valves appear almost ac-line. Furthermore, praecardiids are moderately inflated, whereasVetupraeca is much more convex.

Vetupraeca also lacks a morphologic character considered in-dicative of Praecardium sensu stricto, the presence of vertical‘‘riblets’’ below the beak (Fig. 2.3, 2.5). These riblets present ahinge structure consisting of a various number of small, uprightteeth, located beneath the beak (Fig. 2.5). Conrath (1887) exam-ined this hinge type in Late Silurian bivalves and figured Prae-cardium primulum displaying a row of little teeth, which startbelow the umbo and proceed to the anterior portion of the hingeline. Neumayr (1891) was of the opinion that these teeth emergedfrom the prominent radial ornamentation. He felt that the teethwere modified terminations of these radial ribs and supported thecohesion of the valves. The nature of this feature is rather prob-lematic, as it probably represents a form of primitive paleotaxo-dont dentition composed of modified, radial ornamentation ele-ments (for further discussion see Conrath, 1887; Johnston andCollom, 1998). Beushausen (1895) and Clarke (1904) had alreadynoted that there are no traces of these teeth in the Late Devonianmaterial, nor have they been found to date. In summary, basedon pronounced morphological differences, the Late Devonian taxacannot be placed in Praecardium and, due to the lack of anysuitable Devonian genus, it is necessary to erect Vetupraeca.

To complete the overview of Late Devonian species that havebeen placed within Praecardium, P. angulatum should be brieflydiscussed. Walther (1907) described this species from the Frasnianof Kirschkau (eastern Thuringia, Germany). The only specimen,which is the holotype by monotypy, is oval in outline and theornamentation consists of radial ribs that together with the inter-spaces develop ridges. Unfortunately, the specimen could not betraced for this study, and is, as Walther stated, poorly preserved.Its features, especially the ornamentation, seem to exclude P. an-gulatum unequivocally from both Vetupraeca and Praecardium.The ornamentation resembles specimens that have been deter-mined as Regina vola (Beushausen, 1895), but the true affiliationof this taxon is ambiguous. Praecardium angulatum is, by virtueof its ornamentation, not a representative of Vetupraeca, and can-not currently be re-assigned to any valid taxon.

VETUPRAECA VETUSTA (Hall, 1843)Figure 5.1–5.14

Cardiola duplicata MUNSTER (partim), 1840, p. 68, pl. 13, fig. 20a; KAYSER,1873, p. 639; FRECH, 1887, p. 377; HOLZAPFEL, 1882, p. 254.

Cardium? vetustum HALL, 1843, p. 245, pl. 107, fig. 2.Cardiola Nehdensis KAYSER, 1873, p. 639, pl. 21, figs. 2,3; GURICH, 1896,

p. 98; FRECH, 1887, p. 370, 377.Cardiola vetusta (MILLER, 1877), p. 186.Praecardium vetustum (HALL, 1885), p. 427, pl. 70, figs. 18–20; BEUSHAU-

SEN, 1895, p. 301, pl. 31, figs. 6,7; CLARKE, 1904, p. 306, pl. 11, figs. 11–19; SOBOLEW, 1911, p. 36, 37; GRUNEBERG, 1925, p. 55; MATERN, 1931,p. 12; PAECKELMANN and KUHNE, 1936a, p. 18; TERMIER and TERMIER,1951, p. 65; WURM, 1961, p. 133; JUX and KRATH, 1974, p. 130, fig. b1,b2;KAEVER et al., 1980, p. 151, pl. 24, fig. 2; BECKER, 1993, p. 80, 81, 88,115, 121, 122, 128.

1153NAGEL-MYERS ET AL.—DEVONIAN BIVALVES FROM HERCYNIAN FACIES

FIGURE 3—Length/height ratio of Vetupraeca species showing isometric growth and restricted shape variability.

FIGURE 4—Stratigraphic table of the Late Devonian and range of Vetupraeca taxa and Mucopraeca.

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1155NAGEL-MYERS ET AL.—DEVONIAN BIVALVES FROM HERCYNIAN FACIES

←

FIGURE 5—1, Vetupraeca vetusta, right valve, holotype Cardium ? vetustum, AMNH-F1-42169, Gowanda Shale, �4; 2, Vetupraeca vetusta, right valve,Enkeberg, GZG 1258-2, �5; 3, Vetupraeca vetusta, left valve, hypotype of Praecardium vetustum, AMNH-F1-42170, Gowanda Shale, �2.6; 4–5, Vetupraecavetusta, left valve, MB.M.4205, Enkeberg, �6, (arrow indicating bifurcate ribs); 6–8, Vetupraeca vetusta, steinkern, MB.M.4198, Nehden Shale, �3; 9–11,Vetupraeca vetusta, steinkern, B6A-35.22, Knoppenbissen Formation, �3; 12–14, Vetupraeca vetusta, steinkern, neotype Cardiola nehdensis, MB.M.4190,Nehden Shale, �4; 15, Vetupraeca duplicata, right valve, lectotype Cardiola duplicata, AS VII 366, Gattendorf, �2; 16, Vetupraeca duplicata, right valve,GZG 490-106, Enkeberg, �2, (arrow indicating bifurcate ribs).

Praecardium cf. vetustum (Hall, 1843), AMLER, 2004, p. 165.Praecardium duplicatum (SCHMIDT, 1922), p. 274; SCHINDEWOLF, 1923, p.

277; LANGE, 1929, p. 14; PAECKELMANN and KUHNE, 1936b, p. 26.

Holotype (by monotypy).⎯AMNH-F1-42169.Type locality.⎯Portage (Chautauqua County, New York, north-

eastern North America).Type stratum.⎯Gowanda Shale (Early Famennian, Early Neh-

denian, UD II-C).Material.⎯Holotype of Cardium? vetustum, AMNH-F1-42169, from Por-

tage, Chautauqua, New York (Hall collection); hypotypes of Praecardiumvetustum, AMNH-F1-42170–71, from Portage, Chautauqua, New York (Hallcollection); neotype of Cardiola nehdensis, MB.M.4190, from Nehden(Denckmann collection); topotype of Cardiola nehdensis, MB.M.4198, fromNehden (Denckmann collection); B6A-35.17–20, B6A-35.22, and B6A-35.25from Bergisch Gladbach (Ebbighausen collection); MB.M.4189, MB.M.4191,MB.M.4197, MB.M.4200, and MB.M.4202 from Biesenberg (Denckmanncollection); B6A-35.4 from Col du Puech de la Suque (Becker collection);MB.M.4181 (Paeckelmann collection), 490-105, GZG 1258-2 and GZG1258-4 (v. Koenen collection) from Enkeberg; MB.M.4182–83 from Eskes-berg (Gruneberg collection); MB.M.2230, MB.M.2228, and MB.M.2229.1–2from Gattendorf (Schneider collection); B6A-35.1, B6A-35.2 and B6A-35.14from Combe de Izarne (Becker collection); B6A-35. 3, B6A-35.5, and B6A-35.8–12 from Mentaresses (Becker collection).

Diagnosis.⎯Shells trigonal, more or less pointed, strongly in-flated, umbo distinctly projecting over hinge line. 9–11 radial ribs,oblong in cross section; faint commarginal growth lines.

Description.⎯Shells equivalve, strongly inequilateral, prosocline. Varia-tion range of outline limited, growth isometric (Fig. 3). Umbos prosogyrate,situated anteriorly, terminal. Long posterior dorsal margin, straight to slightlyconvex, merging elliptically into ventral margin. Anterior margin short,straight to slightly convex, declining abruptly from the beak. Ornamentationconsisting of radial costae and fine, commarginal, closely spaced growth lines;radial plications preserved only on steinkerns (e.g., B6A-35.22, Fig. 5.9;MB.M.4190, Fig. 5.13); 9–11 radial ribs, evenly distributed. Ribs on stein-kerns becoming rounded towards umbo. Interspaces plane, almost as wide asor wider than the ribs. Plications broadening slightly towards the margins(e.g., B6A-35.22, Fig. 5.9). Radial ribs appear early in ontogeny, interlockingat the commissure; rib count constant through ontogeny. Ribs in posterior partof shell bifurcate (Fig. 5.5), central and anterior ribs weaker. Dentition andinternal features unknown. Holotype (AMNH-F1-42169, Fig. 5.1) displayscommarginal and radial ornamentation. All specimens from the Hall collectionare slightly distorted.

Measurements.⎯Largest specimen (B6A-35.18): height, 19.7 cm; length23.1 cm; smallest specimen (B6A-35.4): height, 4.7 cm; length, 5.3 cm; var-iation of length/height ratio see Figure 3.

Occurrence.⎯The oldest occurrence of V. vetusta is reported from theupper Kellwasser beds (latest Frasnian) of Coumiac (Becker and House,1994). Holzapfel (1882) reported this species from the same level of theMartenberg (northeastern Rhenish Massif, Germany). Frech (1887) reportedthe occurrence of V. vetusta from Frasnian strata near Combe de Izarne. In afootnote (p. 377), he explained that it was difficult to definitely identify thecollected bivalves. Furthermore, caution is advised concerning the correct age,due to the tectonic situation at Combe d’Izarne (Becker, 1993). Gurich (1896)mentioned V. vetusta from the cephalopod limestones of Lagow in the HolyCross Mountains (Poland). The associated goniatites, especially Maenecerasand Paratornoceras, suggest dating as Adorfian (UD I-F and UD I-G), butthe section is condensed and there are no precise data available that are basedon high-resolution, bed-by-bed collecting. Conodont data suggest that earlyFamennian strata are present at Lagow.

The oldest specimen examined in the present study is from the early Fa-mennian (Nehdenian, UD II-B) of Col de Puech de la Suque (Becker, 1993).Specimens from Eskesberg (Gruneberg, 1925) and from Enkeberg are fromthe Nehdenian, (UD II-D/II-E). Furthermore, specimens from Nehden in theeastern Rhenish Massif, as well as the material from Combe dIzarne of theCabrieres area, fall in the early Famennian (Nehdenian, UD II-C/II-E; Becker,1993). The age of the material from the Biesenberg cannot be determinedexactly, as the assigned ‘‘Unterer Clymenienkalk’’ (Denckmann, 1895) only

allows a broad interpretation as Nehdenian (UD II-A/F). Specimens from Gat-tendorf come from the early Famennian (Nehdenian, UD II) but also cannotbe more precisely constrained, and re-collection at this outcrop has becomeimpossible due to its partial destruction.

The youngest occurrences of V. vetustum are reported from the early Fa-mennian (Nehdenian, UD II-C/E) of the Knoppenbissen Formation (Jux andKrath, 1974) and from the Nehdenian (top of UD II-D) of Mentaresses (Beck-er, 1993). Furthermore, Becker (1993) mentioned V. vetusta from variouslocalities of the Tafilalt of southeastern Morocco (Bou Tchrafine, El Gara,Jebel Ihrs and Dar Kaoua). This material is currently not available, but as-sociated goniatites show that these occurrences can be assigned to the intervalUD II-B/D of the Nehdenian. Termier and Termier (1951) described a Mor-occan occurrence of this species from the southern Meseta (Nehdenian, UDII).

Hall’s (1843) material comes from a locality and stratigraphic level consid-ered to be from the early Famennian Gowanda Shale (Nehdenian, UD II-C)of New York. The specimens of Clarke (1904) from the same region appearto be contemporaneous.

Sobolew (1911) mentioned Praecardium vetustum in his faunal list forKielce-Sandomierze (Holy Cross Mountains, Poland), but the reported fossilassemblage represents various early Famennian levels ranging from Nehden-ian (UD II-C) up to the Hembergian (UD III-C), and the precise locale, andtherefore age, of the specimens is unknown.

Discussion.⎯Cardium? vetustum was described from the Go-wanda Shale (western New York State) by Hall (1843), and helater (1885) added two hypotypes (AMNH-F1-42170–71) to theholotype (AMNH-F1-42169) from the same locality. Hall (1883)assigned his species to the Silurian genus Praecardium. Beushau-sen (1895) re-studied V. vetusta and reported it for the first timefrom Germany. In the course of his study, he (1895) recognizedCardiola nehdensis, originally described by Kayser (1873) fromNehden, as a subjective synonym of V. vetusta. The two syntypesof Cardiola nehdensis are presumably lost and consequently, aneotype (MB.M.4190, Fig. 5.12–5.14) from the Nehden type lo-cality and from the type horizon (Nehden Shales, UD II-B/E) isselected. The neotype clearly defines Cardiola nehdensis, andplaces it unequivocally in synonymy with V. vetusta.

Out of the material Kayser (1873) studied, only MB.M.2228from Gattendorf survived. While Munster (1840) assigned thisspecimen to Cardiola duplicata, Kayser (1873, p. 638) identifiedit as Cardiola nehdensis. Later, MB.M.2228 was re-assigned toP. vetustum by Beushausen (1895) and this study confirms hisdesignation, althought is now assigned to V. vetusta.

Due to the vague definition of Cardiola duplicata Munster(1840), there was never a distinction between it and V. vetusta.The only character used for differentiating the two taxa was thebifurcation of the ribs, which was supposed to be a feature char-acteristic to C. duplicata. Schindewolf (1923) suggested that thiscould be an ornamental difference between steinkern and shellpreservation and not a species-level character, and this is sup-ported by our study. Bifurcate ribs are more weakly developed inV. vetusta, as in V. duplicata, but they are present. Therefore, thetwo syntypes of Cardiola duplicata (MB.M 2219.1–2) are re-assigned to V. vetusta.

VETUPRAECA DUPLICATA (Munster, 1840)Figures 5.15, 5.16, 6.13

Cardiola duplicata MUNSTER, 1840, (partim) p. 68, pl. 13, fig. 20a; KAYSER,1873, (non) p. 639, pl. 21, fig. 4; 1849–56 SANDBERGER and SANDBERGER,(non) p. 271, pl. 28, fig. 7.

Praecardium duplicatum (BEUSHAUSEN, 1895), p. 303, pl. 31, fig. 4; CLARKE,1904, p. 307, pl. 11, fig. 25; Kaever et al., 1980, p. 151, pl. 24, fig. 1;BECKER, 1993, p. 80, 81; KRIZ 2004, p. 88, pl. 1, figs. 1–6.

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[Gowanda Shale (Early Famennian, Early Nehdenian (UD II)]

Lectotype.⎯AS VII 366.Type locality.⎯Gattendorf.Type stratum.⎯‘‘Oberdevon’’ (Early Famennian, Nehdenian,

UD II).Material.⎯Lectotype of Cardiola duplicata, AS VII 366 from Gattendorf

(Munster collection); MB.M.2227 from Gattendorf (collection Munster); GZG490-106 from Enkeberg (v. Koenen collection); MB.M.4203, MB.M.4194,MB.M. 4196, and MB.M.4199 from Biesenberg (Denckmann collection);MB.M.4192 from Eskesberg (Gruneberg collection); B6A-35.21, B6A-35.23and B6A-35.34 from Bergisch Gladbach (Ebbighausen collection); B6A-35.6,B6A-35.15 (Becker collection) and GZG 1258-1 (Chelius collection) fromNehden; B6A-35.7, B6A-35.9, and B6A-35.12–13 from Mentaresses (Beckercollection).

Diagnosis.⎯Shells trigonal to subtrigonal, inflated, umbo pro-jecting over hinge line. 13–15 radial ribs, markedly rectangularin outline; commarginal growth lines.

Description.⎯Comparison with V. vetusta: valves less pointed in outline,posterior dorsal margin more convex, anterior margin somewhat longer andconvex, slightly less inflated. Variation of outline restricted, growth isometric,same length/height ratio as V. vetusta (Fig. 3). 13–15 ribs. Ribs slightly broad-er, in preserved shell distinctly bifurcate (e.g., GZG 490-106, Fig. 5.16), ribmargins developing more or less sharply raised edges on steinkerns (e.g.,B6A-35.7, Fig. 6.13). Commarginal growth lines, sometimes observable oncomposite molds or shell preservation. Interspaces more or less as wide asribs. Internal features and dentition unknown. Lectotype (AS VII 366, Fig.5.15) with shell and internal mold. Triangular posterior adductor muscle scardeveloped (Kriz, 2004).

Measurements.⎯Largest specimen (AS VII 366): height, 20.2 cm; length,25.5 cm; smallest specimen (B6A-35.6): height, 6.5 cm; length, 9.3 cm; var-iation of length/height ratio see Figure 3.

Occurrence.⎯Vetupraeca duplicata ranges from the latest Frasnian to theearly Famennian (UD I-L/II-E). Kriz (2004) reported the oldest occurrence ofV. duplicata from the latest Frasnian of Mentaresses and Combe d’Izarne.The specimens reported from the Knoppenbissen Formation (Jux and Krath,1974) are Nehdenian (UD II-C/E). Specimens from Barmen and Eskesberg(Gruneberg, 1925) are from the early Famennian (Nehdenian, UD II-D/E).Material from the Biesenberg (Denckmann, 1895) cannot be precisely located,because the provided age information as ‘‘Unterer Clymenienkalk’’ is a unitthat correlates to the entire Nehdenian (UD II-A/F). This species also hasbeen mentioned from the Frasnian of Combe d’Izarne (Frech, 1887; Kriz,2004). Due to the tectonic situation at this locality, caution is advised con-cerning the true age (Becker, 1993). Additional material has been collectedfrom the early Famennian at La Serre (Kriz, 2004).

Discussion.⎯The description given by Munster (1840) is veryambiguous and so is the type material. Kayser (1873) suggestedthat the species’ diagnosis was inadequate. He noted that the orig-inal description does not offer a clear definition and that the orig-inal figures do not bear much resemblance to the correspondingtypes (MB.M.2229, Fig. 6.16, 6.18; MB.M.2219.1–2). Further-more, he stated that the only common feature of the examinedspecimens was the bifurcation of the ribs. He figured specimenMB.M.2229 (Kayser, 1873; pl. 21, fig. 4), which he thought tobe the only well-preserved type specimen. Kayser (1873), how-ever, did not consider another well preserved type (AS VII 366,Fig. 5.15), which shows bifurcate ribs in shell preservation as wellas the smooth surface of the steinkern, and is chosen as lectotype.

AS VII 366 (Fig. 5.15) is selected as lectotype for Cardioladuplicata, as it displays all the characters of the species. It con-tains both shell material and an internal mold. The latter showsthat the radial ribs are rounded, becoming broader towards themargins; no depression can be observed on the plications of theinternal mold. The outer shell displays ribs that are rectangular incross-section and that centrally develop a faint groove. This de-pression on the costae was described by Munster (1840) as thedistinguishing feature of C. duplicata, but, in fact, it appears moreor less clearly developed in all Vetupraeca species. Herein, syn-types MB.M.2219.1–2 are reassigned to V. vetusta, andMB.M.2229 (Fig. 6.15–18) is included in Mucopraeca n. gen.(see below).

Gruneberg (1925) reported Praecardium vetustum from Bar-men and Eskesberg. One of these distorted specimens from Es-kesberg has to be reassigned to V. duplicata, due to its highernumber of ribs.

Sandberger and Sandberger (1849–56) assigned one specimenfrom the Frasnian of Oberscheld (eastern Rhenish Massif, Ger-many) to Cardiola duplicata; this specimen is apparently lost.Kayser (1873) stated in his comparison of Cardiola nehdensis andC. duplicata that the almost symmetric, rounded outline of thevalve and the radial ribs, which also display small secondary ridg-es, clearly separate the Oberscheld specimen from C. duplicata.Beushausen restudied and described this specimen as a new spe-cies, Cardiola sandbergeri (1895, p. 304; p. 334, pl. 36, figs. 8,9), supporting Kayser’s contention. The shell outline clearly ex-cludes this species from Vetupraeca. The generic affinity of ‘‘C.’’sandbergeri awaits a revision of the Devonian ‘‘cardiolids.’’

Clarke (1904) described Praecardium duplicatum from John-son’s Falls near Strykersville (Chautauqua subprovince, NewYork State) within the Frasnian/Famennian transition. This spec-imen develops a considerably more prominent and larger umbothan V. duplicata. The radial ribs of this North American speci-men are characterized by a deep furrow, which generates sharpedges on the margins of each rib. The depression on the ribs isas deep as the interspaces. Furthermore, the more or less roundedand symmetric outline of this shell does not correspond to thesubtrigonal valve shape of Vetupraeca.

Kriz (2004) placed V. vetusta in synonymy with V. duplicata.This study, however, suggests that both species are distinct.

VETUPRAECA CLYMENIAE (Beushausen, 1895)Figure 6.1–6.8, 6.14

Praecardium vetustum var. Clymeniae BEUSHAUSEN, 1895, p. 302, pl. 31,fig. 7.

Cardiola Clymeniae BEUSHAUSEN, 1895, (non) p. 357, pl. 37, fig. 21.Praecardium sp. BEUSHAUSEN, 1895, p. 302, pl. 31, fig. 71.Praecardium clymeniae JUX and KRATH, 1974, p. 130, fig. 5 a1–a3.

Neotype.⎯GZG 490-107.Type locality.⎯Enkeberg.Type stratum.⎯‘‘Clymenienkalk’’ (Early Famennian, Nehden-

ian, UD II).Material.⎯Neotype of Praecardium clymeniae GZG 490-107 from En-

keberg (von Koenen collection); B6A-35.26-36 from Bergisch Gladbach (Eb-bighausen collection); MB.M.4185-88 from Eskesberg (Gruneberg collec-tion); B6A-35.16 from Nehden (Becker collection); MB.M.2231 from Villmar(Philippi collection).

Diagnosis.⎯Shells subtrigonal, more or less inflated. 21–24radial ribs, distinct commarginal growth lines.

Description.⎯Comparison with V. vetusta and V. duplicata: Valves morerounded in outline, ventral margin markedly convex. Posterior dorsal marginelongate, slightly convex. Growth isometric, length/height ratio higher thanin V. vetusta (Fig. 3). Umbo less incurved, almost orthogyrate, developing asmall ridge in front, observable on steinkerns; 21–24 fine radial ribs, posteriorribs not amalgamating, but more subtle and more closely spaced than rest(e.g., B6A-35.35, Fig. 6.5–6.8). Radial ribs strongly bifurcated (GZG 490-107, Fig. 6.14), rounded on internal mold (e.g., B6A-35.26, Fig. 6.1–6.4).Distinct, irregular, commarginal lines visible (e.g., B6A-35.35, Fig. 6.5): com-marginal growth lines intersecting radial ribs and interspaces (GZG 490-107,Fig. 6.14). Dentition and internal features unknown. Lectotype (GZG 490-107, Fig. 6.14) with shell preservation, dorsal region poorly preserved.

Measurements.⎯Largest specimen (GZG 490-107): height, 18.9 cm;length, 25.2 cm; smallest specimen (B6A-35.27): height, 5.9 cm; length, 7.1cm; variation of length/height ratio see Figure 3.

Occurrence.⎯The oldest occurrence of V. clymeniae is reported from earlyFamennian (Nehdenian, UD II-C/E) of the Knoppenbissen Formation (Jux andKrath, 1974). Specimens from Eskesberg (Gruneberg, 1925) are from theNehdenian, (UD II-D or UD II-E). The specimen from the Biesenberg allowsonly a broad interpretation as early Famennian (Nehdenian, UD II-A/F), sincethe old stratigraphic assignment as ‘‘Unterer Clymenienkalk’’ (Denckmann,1895) cannot be dated precisely. V. clymeniae is currently restricted to Rhen-ish Massif localities.

Discussion.⎯Beushausen (1895) described P. vetustum var.

1157NAGEL-MYERS ET AL.—DEVONIAN BIVALVES FROM HERCYNIAN FACIES

FIGURE 6—1–4, Vetupraeca clymeniae, steinkern, B6A-35.26, Knoppenbissen Formation, �3.2; 5–8, Vetupraeca clymeniae, steinkern, B6A-35.35, Knop-penbissen Formation, �3.7; 9–12, Mucopraeca multicostata, steinkern, B6A-35.39, Knoppenbissen Formation, �5.6; 13, Vetupraeca duplicata, right valve,internal mold, B6A-35.35, Mentaresses, �2.3; 14, Vetupraeca clymeniae, right valve, neotype Praecardium clymeniae, GZG 490-107, Enkeberg, �2, (arrowindicating bifurcate ribs); 15, Mucopraeca multicostata, right valve, lectotype Praecardium multicostatum, NYSM 5493, Gowanda Shale, �4.5; 16–18,Mucopraeca multicostata, right valve, MB.M.2229, Gattendorf, �1.2, (arrow indicating comarginal incision).

1158 JOURNAL OF PALEONTOLOGY, V. 82, NO. 6, 2008

clymeniae in his comments on Praecardium vetustum. He men-tioned two original specimens, both from the the Enkeberg lime-stone. One of the specimens was questionably assigned to Car-diola nehdensis. Kayser (1873) and Beushausen (1895) stated thatthis specimen displays a higher number and more closely spacedribs than all other related taxa. The second was a poorly preservedspecimen, which was housed in the Geowissenschaftliches Zen-trum der Universitat Gottingen. Unfortunately, both types are nowlost. Therefore, a neotype (GZG 490-107, Fig. 6.14) from the typelocality is selected here. Beushausen (1895) identified this spec-imen as Praecardium sp. and observed that, in contrast to spec-imen GZG 490-106 (Fig. 5.16), which he identified as P. dupli-catum, the number of ribs is higher. Although the old stratigraphicdetermination as ‘‘Clymenienkalk’’ (Beushausen, 1895) does notprovide information on the precise age of the neotype, it is mostprobable that the lost type and the neotype are contemporaneousbecause both come from the collection of v. Koenen from theEnkeberg type locality. The age of these specimens may representthe total range of this section, from the Nehdenian up to the Hem-bergian (Korn and Ziegler, 2002). Resampling (Becker, 1993) didnot provide new material and the precise age needs to be inferredfrom better-constrained material of other localities.

Jux and Krath (1974) cited V. clymeniae from the Knoppen-bissen Formation, the first citation of this taxon since its originaldescription. Despite its attribution to this taxon, Cardiola clymen-iae of Beushausen (1895, p. 357, pl. 37, fig. 21) is a distinctspecies with no relational affinities to Vetupraeca.

VETUPRAECA MELLETES (Clarke, 1904)Praecardium melletes CLARKE, 1904, p. 307, pl. 11, fig. 20.

Holotype (by monotypy).⎯The specimen illustrated by Clarke(1904) and housed in the New York State Museum, Albany.

Type locality.⎯Forestville (Chautauqua County, New York,northeastern North America).

Type stratum.⎯Sandstone at the top of the Portage Shales(probably Gowanda Shale, Nehdenian, UD II-C).

Diagnosis.⎯As for Vetupraeca vetusta, with only six radialribs.

Description.⎯Valves comprise all features of V. vetusta, but with only sixradial ribs. Internal features unknown.

Measurements.⎯Specimen: height, 6 mm; length, 7.5 mm.Discussion.⎯Praecardium melletes Clarke was based on a sin-

gle valve from near Forestville (Chautauqua County, New York).Based on current lithostratigraphy (Tesmer, 1967), the specimenprobably comes from the Gowanda Shale, which is early Famen-nian (Nehdenian, UD II-C; Becker and House, 2000). The spec-imen closely resembles V. vetusta, but has only six radial ribs.Clarke (1904) felt that this feature was important enough forerecting a new species, Praecardium melletes. Vetupraeca vetustahas never been observed with less than nine ribs. The NorthAmerican species, therefore, lies outside the known range of var-iation of V. vetusta. The appearance of all ribs in an early growthstage in Vetupraeca also suggests that the early rib number is notan ontogenetic variation in the growth pattern, but a distinguish-ing character at the species level. To obtain further clarificationof whether this taxon represents a regional variation (i.e., a sub-species) of V. vetusta or a separate taxon, recollecting in the typearea is necessary to establish its variability and to stabilize itspossible status as a North American species or subspecies.

Genus MUCOPRAECA new genusType species.⎯Praecardium multicostatum Clarke, 1904.Included species.⎯Praecardium multicostatum.Diagnosis.⎯Shells subcircular, slightly inequilateral, equival-

ved; umbos small, central, prosogyrate. Broad, flat radial bifur-cated ribs; minute, commarginal striae. Ribs broaden slightly atmargin. Dentition unknown; dimyarian, more or less equallywide, narrow, slightly elongated adductor muscle scars.

Discussion.⎯Mucopraeca n. gen. is distinguished from Vetu-praeca by its subcircular and slightly inequilateral outline as wellas by its centrally located umbo as compared to the prosoclinemorphology of the latter. Although Mucopraeca’s outline resem-bles that of Praecardium more closely than that of Vetupraeca,the lack of riblets beneath the umbo and its small umbo distin-guish it distinctly from the Late Silurian taxon. Based on thesefeatures, as well as the lack of any existing genus that encom-passes the morphology of this group, Mucopraeca is established.

Etymology.⎯Anagram of syllables of the species ‘‘multicostatum’’ and thegenus ‘‘Praecardium.’’

Occurrence.⎯Mucopraeca occurs in the North American Gowanda Shalewhich, judging from the associated ammonoid fauna, represents the early Fa-mennian (Nehdenian, UD II-C). In Europe, this taxon appears in the earlyFamennian of the Wuppertal region (northern Rhenish Massif, Germany), theKnoppenbissen Formation, and Gattendorf.

MUCOPRAECA MULTICOSTATA Clarke, 1904Figure 6.9–6.12, 6.15–6.16

Cardiola duplicata MUNSTER, 1840, (partim) p. 68, pl. 12, fig. 21; KAYSER,1873, p. 639, pl. 21, fig. 4; BEUSHAUSEN, 1895, p. 304.

Praecardium multicostatum CLARKE, 1904, p. 308, pl. 11, figs. 21, 22, 24,BAIRD and LASH, 1990, p. A34.

Praecardium n. sp. aff. multicostatum PAECKELMANN, 1913, 256, pl. 6, fig.2, 2a; GRUNEBERG, 1925, p. 55.

Lectotype.⎯NYSM 5493.Type locality.⎯Walnut Creek, (Forestville, New York, north-

eastern North America).Type stratum.⎯Gowanda Shale, (Early Famennian, Nehdenian,

UD II-C).Material.⎯Lectotype of Praecardium multicostatum NYSM 5493, from

Walnut Creek, Forestville (Clarke collection); paralectotypes of Praecardiummulticostatum NYSM 5490–91, from Walnut Creek, Forestville (Clarke col-lection); NYSM 11426 from western New York State (Tesmer collection);syntype MB.M.2229 of Cardiola duplicata from Gattendorf; B6A-35.37–40from Bergisch Gladbach (Ebbighausen collection).

Description.⎯Shells rounded, slightly inequilateral, equivalve. Anteriordorsal valve region somewhat obtuse, posterior slightly elongated. Anteriordorsal margin shorter than posterior part. Umbo central, slightly prosogyrate,separated by clear incision from valve on steinkerns as well as on shell (B6A-35.39, Fig. 6.9–6.12; NYSM 5493, Fig. 6.15). Valve regularly convex, slightlyelevated in the umbonal region. 20–22 radial ribs broad, slightly raised edges,bifurcate. Ribs somewhat broader than interspaces, both flat and regularlyspaced. Traces of minute commarginal striae on shell, sometimes showingthree conspicuous comarginal incisions parallel to anterior dorsal margin(MB.M.2229, Fig. 6.16–6.18). Lectotype slightly and paralectotypes as wellas hypotypes markedly distorted taphonomically (NYSM 5493, Fig. 6.15;NYSM 5491; NYSM 5490). Probably dimyarian, faint traces of two, more orless equally wide, narrow, slightly elongated adductor scars on pyritic stein-kern (B6A-35.38). Dentition unknown.

Measurements.⎯Largest specimen (MB.M.2229): height, 17.3 cm; length,16.7 cm; smallest specimen (B6A-35.39): height, 8.5 cm; length, 8.5 cm.

Occurrence.⎯The type of M. multicostata probably was collected fromthe Gowanda Shale (western New York State), as the Hanover Shale, whichalso crops out in Walnut Creek, is closer to Silver Creek on the Lake Erieshoreline. NYSM 11426 was collected near Smith’s Mills Station and is fromthe Gowanda Shale (Nehdenian, UD II-C). Furthermore, Baird and Lash(1990) reported one specimen from the Gowanda Member of Corell’s Point,which is, judging from the associated ammonoid fauna, also UD II-C of theNehdenian. The European occurrences of this taxon are from the early Fa-mennian of the Wuppertal region (Nehdenian, UD II B/D) and from the Knop-penbissen Formation of Bergisch Gladbach. The only specimen from Gatten-dorf is MB.M.2229; the closest it can be dated is presumably Famennian(Nehdenian, UD II). Its precise level is ambiguous and re-collecting from thisoutcrop has become impossible due to the partial destruction of the outcrop.

Discussion.⎯Clarke (1904) described Praecardium multicos-tatum from Walnut Creek, Forestville. Four syntype specimenswere figured and three of these survive (Clarke, 1904, pl. 11, figs.21, 22, 24). All syntypes are distorted, and the best preserved(NYSM 5493, Fig. 6.15) is selected as the lectotype. The sym-metry of the valves and the grade of the ribs place this taxoncloser to the buchiolids, but the ornamentation of M. multicosta-tum, especially the bifurcation and the incision, which separatesthe umbo from the rest of the shell, contradicts such affinity(Grimm, 1998).

1159NAGEL-MYERS ET AL.—DEVONIAN BIVALVES FROM HERCYNIAN FACIES

The excluded syntype MB.M.2229 of Cardiola duplicata Mun-ster (see above), although partially damaged, shows characters ofM. multicostata, and is therefore re-assigned to it.

Paeckelmann (1913) described a poorly preserved specimenfrom Hahnenfurt (northern Rhenish Massif) as Praecardium n.sp. aff. multicostatum. He noted that it was very similar to M.multicostata and that just the development of the bifurcation ofthe ribs was less distinct. Our re-study of Clarke’s type specimensshowed that the ribs of the syntypes are less markedly bifurcatethan originally figured. Therefore, the specimen from the Ber-gisches Land can be reassigned to M. multicostata, as well as adistorted specimen from Eskesberg (MB.M 4188), which was alsoidentified as Praecardium n. sp. aff. multicostatum by Gruneberg(1925).

The figured specimen B6A-35.39 (Fig. 6.9–12) displays detailsof the inner shell surface. The development of its umbo is anartifact of preservation and does not indicate a strongly developednepioconch.

PALEOECOLOGICAL DISCUSSION

Members of Vetupraeca as well as Mucopraeca are widespreadin hypoxic shales, marls and limestones. This facies necessitatessome kind of adaptation to eutrophic and low-oxygen conditions.The small size of these taxa relative to their large surface areamay have enabled them to inhabit these dysoxic environments(Levin, 2003; Wignall, 1990), because, as with many invertebrateswith an open blood system, bivalves can increase their oxygenuptake by adsorption (Oschmann, 1994). This maximized surface-volume ratio could have also provided more support of the sub-strate per unit of animal weight for these soft-sediment dwellers(Stanley, 1970). The assumption that these taxa could have adapt-ed to their environment by an endosymbiosis with chemoautotro-phic bacteria (Seilacher, 1990) is questionable. This life habit isimpossible in dysaerobic environments because temporary oxy-genation episodes, as well as oxygen in the bottom water, wouldexclude free H2S, which is necessary for a chemosymbiosis(Oschmann, 1994).

A pseudoplanktonic life habit that has been reported for otherDevonian taxa as a means to escape hostile conditions on thesubstrate (Nagel-Myers and Amler, 2007) cannot be applied forVetupraeca or Mucropraeca. They do not develop a byssus, andthere is no evidence in the fossil record that these taxa attachedto objects, as there has been for other groups (Nye et al., 1975;Nagel-Myers and Amler, 2007).

Unfortunately, apart from the shell symmetry, there are no fur-ther indications substantiating an interpretation of their life habits.Judging from the morphology of Vetupraeca, the lack of a strongfoot and a pallial sinus, it is unlikely that these taxa were burrow-ers. The trigonal shell shape suggests that they lay with their longaxis in some angle to the substrate to elevate the posterior portionof the shell (Stanley, 1970). There are no indications of a byssusor siphons and therefore Vetupraeca is assumed to have been anepibenthic suspension feeder.

Mucopraeca, in contrast, develops a broadly elliptical to sub-circular outline. This may indicate that they were burrowing sus-pension feeders (Stanley, 1970), as proposed by Kriz (2004) forthe Late Silurian Praecardium taxa. However, due to the missingdata on their soft body organization, an assumption concerningtheir life habits cannot yet be made.

CONCLUSIONS

The frequently described group of radially ribbed bivalves fromthe Late Devonian Hercynian Facies has been placed within twonewly described genera. Currently, five species are thought to beconstituents of the Late Devonian pelagic facies: Vetupraeca ve-tusta, Vetupraeca duplicata, Vetupraeca melletes, Vetupraeca cly-meniae, and Mucopraeca multicostatum. Due to their morpholog-ical differences in outline, ornamentation, and lack of the

characteristic teeth-like structures underneath the beak, their for-mer affiliation to the Late Silurian/Early Devonian PraecardiumBarrande cannot be maintained.

Vetupraeca n. gen. and Mucopraeca n. gen. are characteristictaxa of the Nehdenian (UD II).

The stratigraphic data of the examined specimens suggests thefollowing interpretation of the stratigraphic range of this bivalvegroup (Fig. 4). The first appearance of V. vetusta and V. duplicatalies in the Kellwasser beds of the latest Frasnian (Kriz, 2004;Becker and House, 1994). At the beginning of the Famennian andin the main radiation phase after the Kellwasser crises, V. cly-meniae as well as M. multicostata appeared. It can be assumedthat all four species became extinct contemporaneously at the endof the UD II-E (Nehdenian) during the regressive Condroz Event(Becker, 1993). These taxa were abundant in the Nehdenian, butbased on our current knowledge, it appears that they did not sur-vive it. Vetupraeca melletes is currently represented by only onespecimen from North America; thus, its actual distribution cannotbe determined.

ACKNOWLEDGEMENTS

We would like to thank Martin Aberhahn (Berlin), Volker Ebbighausen(Odenthal), Linda Hernick (Albany), Bushra Hussaini (New York), MikeReich (Gottingen), Vojtech Turek (Prague), and Winfried Werner (Munich)for providing access to collections and specimens. Jeffrey Over (SUNY Ge-neseo, New York State) gave helpful comments on New York stratigraphy.We also thank Paul Johnston, Margaret Bradshaw, and Peter Harries for theirhelpful commentary. This research is supported by the Westfalisches Museumfur Naturkunde, Munster and contributes to IGCP 499 Devonian land-seainteraction: evolution of ecosystems and climate—DEVEC and IGCP 497 theRheic Ocean: Its Origin, Evolution and Correlatives.

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ACCEPTED 8 MAY 2008