High Diversity Bivalve Faunas in the Middle of the Southern Baltic Sea Jens Koppka1, I. Hinz-Schallreuter2 & F.-T. Fürsich3

In the Southern Baltic (Lithuania, southern Latvia, northern Poland, NE-Germany and parts of the Baltic Sea) shallow marine, highly fossilifereous Middle Jurassic strata with uncommonly well-preserved shells are widely distributed but mostly covered by Creteaceous – Quaternary deposits and/or the Baltic Sea. Of the whole region, only the area of Papilė (Popilani, Lithuania) supplies good exposures of marine Middle Jurassic (see e.g. Krenkel 1915, Brinkmann 1924, Grigelis & Norling 1999). These outcrops (see Fig. 1) were studied in detail (bed by bed collection in the jason-, coronatum- and lamberti-Zones) by the first author in 2004. Another important area for bivalve studies is the border region between NW-Poland (Pommerania) and NE-Germany (Vorpommern). Apart from a glacial raft of an Upper Bajocian poorly fossilferous sandstone on the Isle of Gristow (Chrzaszczewska Wyspa near Kamien Pomorski, NW-Poland) Middle Jurassic outcrops are unknown from this region. Therefore, our knowledge about the respective marine Middle Jurassic (Bajoc-Callov) comes from boreholes and a huge amount of glacial erratic boulders (Geschiebe) as well as from few glacial rafts (now poorly exposed or lost). During the glaciation a lot of Jurassic material was eroded from the Pommeranian Swell (see fig. 2) with the erratic boulders (the majority are of Callovian age) now widely distributed in Quaternary deposits of N-Germany and NW-Poland (see Brinkmann 1924, Stoll 1934). They yield numereous extraordinarily well-preserved bivalves and other molluscs, e.g., ammonites which are important for biostratigraphy). Aragonite, colour and ligament preservation (see pl. 1-4) are common among many different lithotypes (e.g., ferrugineus calcareous sandstones, iron oolites, marly limestone nodules, etc.) from the Lower Bajocian to Callovian. Current investigations refer to Fig. 1: Sands and clayey sands of the Lower Callovian (Papilė Formation) and possible connections between extraordinary preservation, lithology and taphonomic-diagenetic processes. Quick sedimentation, high rate of Middle Callovian (Papartinė Formation) in the clay-pit Šaltiškiai, N-Lithuania subsidence and early cementation are probably the main causes for the excellent preservation in many calcareous sandstones of Pommerania. In (near Papile). The glaciotectonically deformed Callovian sands overly red Lithuania nearly perfectly preserved shells occur in weakly or uncemented sands which need another explanation. It might be possible that the clays of the Nemunas-Formation, cl2a = jason-Zone, cl2b = coronatum-Zone. Triassic clays together with the Upper Callovian and Oxfordian claystones in the top closed the system and protected the shells within the sands from dissolution. The frequently observed perfect, Recent-like preservation permits investigations of minute details on bivalve shells. Hinges carefully prepared (by the first author) show all details of the hinge morphology and enable to clarify taxonomic problems, especially in heterodont bivalves (see pl. 2-4). Sometimes, the bivalve shells display interesting microstructures, e.g., the fine striae on the posterior side of Isocyprina and Anisocardia (see tab. 1. fig. 9, 10, 15) or the ultrastructures of various taxa (see cross sections pl. 1, figs. 1, 3, 5, 7). Isolated material from weathered erratic boulders and samples from boreholes of Vorpommern (NE-Germany) enables ontogenetic studies. Well-preserved and isolated prodissoconchs are fairly common in some samples. The bivalve fauna of both Pommerania and Lithuania is highly diverse; after recent investigations of the first author (Koppka 2002, 2004 & unpublished data) more than 160 bivalve species out of approximately 66 genera are known. The diversity maximum occurred in the Middle Callovian (in Pommerania in the Jason-Zone and in Lithuania in the upper Coronatum-Zone). With 19 genera, the infaunal suspension feeding are the major group; typical taxa are Nicaniella, Pressastarte, Tancredia, Protocardia, Anisocardia and Isocyprina. It is noticeable that several species show a strong preference of special environments: small species of Trancredia and Nicaniella (e.g. Nicaniella polita, N. plana and N. morini) and thick shelled species of Pressastarte (Pinguiastarte) are characteristic for high-energy environments (iron-oolites and thin-bedded calcareous sandstones) deposited near-shore. Strongly inflated species of Nicaniella, e.g., Nicaniella (Trautscholdia) cordata and N. (T.) niyayuensis prefer the soft bottom substrate of the clay facies. The deposit feeding Nuculoida are also typical for clay substrates. (with 11 genera) are deep-burrowing infaunal siphonate suspensions-feeders and restricted to more stabile, only storm-affected sandy-clayey Fig. 2: Callovian Palaeogeography of Northern and Eastern Europe (from substrates. Such an environment yields the highest bivalve diversity with more than 70 species for Pommerania and > 40 taxa for Lithuania. The Koppka 2002, modified after Grigelis & Norling 1999: plate 12) with the taxonomic work of the originally poorly known fauna is still under progress. As a first result of the investigations which focussed on Callovian working areas: (1) Pommerania (Pommeranian Swell, northern part of the Middle-Polish Anticlinorium), (2) Lithuania, Latvia and the Kurian part of Heterodonta and Anomalodesmata three new genera (Solecurtoidomya, Erratomya & Pseudoquenstedtia) and five new species from Pommeranian the Baltic Sea. Both areas delivered Middle Jurassic glacial erratic boulders to glacial erratic boulders were described (Koppka 2004). N-Germany, with the bulk coming from the Pommeranian part.

1. Order Nuculoida: Family: Nuculidae (Palaeonucula) Family: Nuculanidae (Dacromya, Mesosacella, Nuculana, Nuculoma)

2. Order Mytiloida: Family: Mytiliidae (Modiolus, Inoperna, Lycettia)

3. Order Arcoida: Family: Grammatodonidae (Dicranodonta, Grammatodon) Family: Arcidae Arca (Eonavicula) Family: Limopsidae (Limopsis)

4. Order Pterioida:

Family: Inoceramidae (Parinoceramus) Family: Pteriidae (?Pteroperna) Family: Bakevelliidae (, Gervillella, Aguilerella) Family: Posidoniidae (Bositra) Family: Isognomonidae (Isognomon) Family: Pinnidae (Pinna)

5. Order Limoida: Family Limidae (Ctenostreon, Plagiostoma, Pseudolimea) 6. Order Ostreoida: Family: Ostreidae (Actinostreon, Exogyra, Nanogyra) Familie: Gryphaeidae (Gryphaea) Family: Plicatulidae (Plicatula)

7. Order Pectinoida: Family: Pectinidae (Camptonectes, Entolium, Radulopecten) Family: Oxytomidae (Meleagrinella, Oxytoma) Familie: Buchiidae (Buchia) Plate 2: 1: Coelopis sp., RV, Lower Callovian, Lentschow (NE-Germany). 2 Trigonastarte sp., RV, M. Family: Anomiidae (Juranomia) Familie: Terquemiidae (Placunopsis) Plate 1: 1-2: Cross section and LV of Nuculoma sp., Upper Bajocian, Pritzier (Vorpommern). 3-4: Trigonia sp. Callovian, Möllenhagen, (NE-Germany). 3: Protocardia (P.) stricklandi (Morris & Lycett, 1853), LV, 3: Cross section showing two different aragonitic shell layers, 4: RV, same erratic boulder as 1; 5-6: Nicaniella Upper Bathonian, Basedow (N-Germany); 4: Corbulomima attenuata (Lycett, 1863), LV, M. Callovian, (N.) cf. pulla (A. Roemer, 1836); 5: Cross section of Nicaniella and other bivalves (e.g., Nuculana, Praesacella, 8. Order Trigonioida: Family: Trigoniidae (Myophorella, Trigonia, Vaugonia) Graßdorf near Leipzig (Saxony, SE-Germany); 5: Nicaniella (Trautscholdia) niyayuensis (Zakharov, Gramma-todon); 6: Lateral and dorsal view of Nicaniella cf. pulla, Upper Bajocian, erratic boulder from Lubin 1970), RV, Upper Callovian (lamberti-Zone) or Lower Oxfordian, Papilė (Lithuania), 6: Tancredia (Lebbin), NW-Poland. 7-8: Camptonectes (C.) auritus (Schlotheim, 1813); 7: Cross section; 8: lateral and internal (Isotancredia) extensa (Lycett, 1850), RV with colour preservation, koenigi-Zone, Lower Callovian, views of a juvenile specimen, erratic boulder, Upper Bajocian, Pritzier (Vorpommern). 9-10: Anisocardia (A.) Superorder Heterodonta Miedzyzdroje (Isle of Wolin, NW-Poland), 7: Corbicellopsis sp., LV, coronatum-Zone, M. Callovian, leporina (Kloeden, 1833); 9: detail of the posterodorsal angle with fine oblique lines crossing the carina and the Papartinė (Lithuania), 8: Tancredia (Corburella) sp., LV, coronatum-Zone, M. Callovian, Papartinė typical radial and concentric ornamentation of Anisocardia, Middle Callovian from Sellin (Isle of Rügen, N- 9. Order Hippuritoida: Familie: Dicerocardiidae (Pseudisocardia) (Lithuania), 9: Solecurtoidomya senftii (Andree, 1860), RV, Greifswalder Oie (Vorpommern, NE- Germany); 10: juvenile specimen with perfect colour preservation, Lower Callovian, from Gusow (Brandenburg, Germany), 10: Anisocardia (?Anisocardia) minima (J. Sowerby, 1812), LV, 10a lateral view, 10b hinge, N-Germany). 11-12: Pleuromya uniformis (J. Sowerby, 1813); 11: RV with colour preservation; 12: detail of the 10. Order Veneroida: Upper Callovian, Lukow (Poland), 11: Anisocardia (Antiquicyprina) bicarinata (Stoll, 1934), 11a RV posteroventral corner schowing the typical shell ornamentation of the species, erratic boulder from Segrahn from Mönchgut (Rügen, Vorpommern), 11b hinge of LV, Göhren (Rügen), both erratic boulders from (Schleswig-Holstein, N-Germany). 13-14: Neocrassina (Neocrassina) ovata (Smith, 1817), complete specimen Family: Corbulidae (Corbulomima) Family: Lucinidae (Mesomiltha, Discomiltha) the Middle Callovian, 12: Isocyprina (Venericyprina) lowei (Krenkel, 1915), RV & LV, M. Callovian, with preserved ligament, Upper Middle Callovian, Papartinė (Lithuania), 15-16: Isocyprina (Venericyprina) Göhren (Rügen, Vorpommern), 13 Sowerbya triangularis (Phillips, 1829), RV, Middle Callovian, lowei (Krenkel, 1915); 15: posteroventral angle of a RV with typical oblique striae, Isle of Rügen (Vorpommern, Family: Unicardiopsidae (Unicardiopsis) Family: Quenstedtiidae (Quenstedtia) Graßdorf near Leipzig (SE-Germany) NE-Germany); 16: RV with colour preservation, Düttebüll (Schleswig-Holstein, N-Germany). Family: Sowerbyidae (Sowerbya) Family: Tancrediidae (Tancredia, Corbicellopsis) Family: Cardiidae (Protocardia) Family: Astartiidae (Coelopis, Prorokia, Neocrassina, Nicaniella, Pressastarte, Trigonastarte) Family: Arcticidae (Anisocardia, Isocyprina) fam. inc. sed. (Solecurtoidomya)

11. Order Modiomorphoida: Familie: Permophoridae (Myoconcha)

12. Order Myoida: Familie Gastrochaenidae (?Gastrochaena) Superorder Anomalodesmata

13. Order Pholadomyoida: L 4,6 cm Family: Pholadomyidae (Goniomya, Machomya, Pholadomya, Pseudoquenstedtia, Erratomya) Family: Ceratomyidae (Gresslya) Family: Myopholadidae (Myopholas) Family: Pleuromyidae (Pleuromya) Family: () Family: Laternulidae (Cercomya)

Fig. 3: Systematic overview about all genera known until now from the Middle Jurassic of Lithuania and from glacial erratic boulders from both Pommerania (Poland) and N-Germany

Plate 4: 1a-b: Myopholas acuticostata (J. de C. Sowerby, 1827); a: LV; b: hinge with strong protu- References berance (teeth), Middle Callovian, Panitsch near Leipzig (Saxonia, SE-Germany). 2a,b: Pseudoquen- Plate 3: 1a,b Pseudolimea sp.; a LV lateral; b beak with prodissoconch, coronatum-Zone, Brinkmann, R. (1924): Der Dogger und Oxford deSüdbaltikums. – Jahrbuch der Preussischen Geologischen stedtia pommerana Koppka, 2004, juvenile RV; a: lateral, b: internal, Middle Callovian, Tramm M. Callovian, Papartinė (Lithuania). 2: Meleagrinella echinata (Smith, 1817), LV, Upper Bathonian, Landesanstalt, 44 [1923]: 477-513, 16 figs.; Berlin. (Schleswig-Holstein, NW-Germany). 3-5: Pleuromya polonica (Laube, 1867) Middle Callovian, Göhren Brinkmann, R. (1927): Der ostpreußisch-litauische Dogger und Unteroxford. – Schriften der Physikalischen- Hohen Wangelin (Mecklenburg, N-Germany). 3, 6 Grammatodon (Gr.) minimus (Leckenby, 1859); (Rügen, NE-Germany); 3: RV, Middle Callovian, Staber Huk (Fehmarn, Schleswig-Holstein, NW- Ökonomischen Gesellschaft zu Königsberg, 65 (2): 49-96, 2 figs.; Königsberg. 3a,b RV, figured as Pseudomacrodon pictum Milaschewitsch in Stoll 1934: pl. 1, fig. 2, M. Callov, Germany); 4: hinge of LV; 5: bivalved specimen with ligament. 6: Thracia (Thracia) depressa (J. de Grigelis, A. & Norling, E. (1999): Jurassic geology and foraminiferal faunas in the NW part of the East European Sellin (Vorpommern), 6:LV,coronatum-Zone, M. Callovian, Papartinė (Lithuania), 4: Pressastarte C. Sowerby, 1823), specimen figured in Stoll 1934: pl.2, fig. 2, Middle Callovian, erratic boulder, Platform. - Sveriges Geologiska Undersökning, Ser. Ca, 89: 101p., 31 figs., 17 pl.; Uppsala. locality unknown (Vorpommern?). 7: Pholadomya (Pholadomya) canaliculata (A. Roemer, 1836), (Pinguiastarte) sp., RV, Lower Callovian, Lubmin (Vorpommern), 5: Pressastarte (Pressastarte) Koppka, J. (2002): Lithologie und Fauna der Kellowaygeschiebe – Fallstudien aus Schleswig-Holstein, Vorpom- nummulina (F. Roemer, 1842), M. Callovian, Graßdorf near Leipzig (SE-Germany), 7: Limopsis cf. complete specimen, Staber Huk (Fehmarn, Schleswig-Holstein, NW-Germany). 8: Gresslya abducta mern und dem Leipziger Raum mit besonderer Berücksichtigung der Heterodonta und Anomalodes- (Phillips, 1829), complete specimen, figured as Gresslya striatopunctata Quenstedt in Stoll 1934: pl. 1, minima (J. de C. Sowerby, 1824), Upper Bathonian, Basedow (Mecklenburg, N-Germany). mata (). – unpublished Diploma-Thesis, 191p., 61 figs., 9 pls., Apendix I-XXIV; Greifswald. fig. 45, Middle Callovian, Lubmin (Vorpommern). Koppka, J. (2004): Neue Bivalven (Heterodonta, Anomalodesmata) aus Kelloway-geschieben Norddeutschlands. – Address of the authors: Archiv für Geschiebekunde, 4 (5): 233-272, 2 pl., 10 figs., 3 tab.; Greifswald. Address of the authors: email: 1 Dipl.-Geol Jens Koppka Krenkel, E. (1915): Die Kelloway-Fauna von Popilani in Westrussland. – Palaeontographica, 61: 191-362, 26 figs., 2 Prof. Ingelore Hinz-Schallreuter 3 Prof. Franz Theodor Fürsich 28 pls.; Stuttgart. [email protected] Ernst-Moritz-Arndt-University, Institute of Stoll, E. (1934): Die Brachiopoden und Mollusken der pommerschen Doggergeschiebe. – Abhandlungen aus dem Institute of Palaontology, Geography und Geology, Dpt. of Palaeontology geologisch-paläontologischen Institut der Ernst Moritz Arndt-Universität Greifswald, 13: 1-62, 2 figs., Julius-Maximilians-University [email protected] and Historical Geology, Friedrich-Ludwig-Jahn- Pleicherwall, D-97070 Würzburg, 4 tab., 3 pls.; Greifswald. [email protected] Str. 17a, D-17489 Greifswald, Germany Germany