A New Deep-Sea Elasmobranch Fauna from The
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27 Zitteliana 90 A new deep-sea elasmobranch fauna from the Central Paratethys (Neuhofener Beds, Mitterdorf, near Passau, Germany, Early Miocene, Middle Paläontologie Bayerische GeoBio- & Geobiologie Staatssammlung Burdigalian)Center LMU München für Paläontologie und Geologie LMU München n München, 2017 Jürgen Pollerspöck1* & Nicolas Straube2 n Manuscript received 1 27.12.2016; revision Benediktinerring 34, 94569 Stephansposching, Germany accepted 01.03.2017; 2Bavarian State Collection of Zoology, Münchhausenstraße 21, 81247 Munich, Germany available online: 11.07.2017 *Corresponding author; E-mail: [email protected] n ISSN 0373-9627 n ISBN 978-3-946705-02-4 Zitteliana 90, 27–53. Abstract In this study, a diverse fauna of fossil elasmobranch teeth from the Early Miocene (Middle Burdigalian) is analysed. The fossil diversity strongly resembles extant deep-water shark and ray assemblages. The fossils were collected from the Upper Marine Molasse of the lower Ottnangian in the Neuhofener Beds location, Mitterdorf, Germany. The collection site is a clay pit in between the Lower Bavarian villages Fürstenzell and Schmidham. The sample revealed 14 shark and four ray species. We present the first record of fossils assigned to taxa Nanocetorhinus tuberculatus, Deania and Apristurus from Germany. In addition, we describe a hitherto unknown genus and species of shark, Pseudoapristurus nonstriatus gen. et sp. nov., based on fossil teeth. The documented diversity is compared to both extant and fossil records of neoselachian deep-water diversities, and it is evident that this Miocene fauna is very similar in composition to indo-pacific deep-water assemblages. Key words: Bavaria, Early Miocene, deep-water, Chondrichthyes, Ottnangian, Burdigalian, Upper Marine Molasse Zusammenfassung Aus der Oberen Meeresmolasse (Neuhofener Schichten, unteres Ottnangium) Niederbayerns (Tongrube zwischen Fürstenzell und Schmidham) wird eine artenreiche Tiefwasser-Elasmobranchierfauna beschrieben. Insgesamt werden 14 Hai- und vier Rochenarten nachgewiesen. Erstnachweise für Deutschland werden von Nanocetorhinus tuberculatus, Apristurus sp. und Deania sp. erbracht. Zusätz- lich wird eine bisher unbekannte Neoselachier Gattung und Art (Pseudoapristurus nonstriatus nov. gen. et sp.) anhand von Zahnfossilien beschrieben. Ein Vergleich der hier dokumentierten Diversität mit verschiedenen anderen rezenten und fossilen Neoselachier Vergesell- schaftungen zeigt, dass die vorliegende Fauna große Übereinstimmungen mit rezenter indo-pazifischer Tiefseediversität aufweist. Schlüsselwörter: Bayern, Unteres Miozän, Tiefsee, Chondrichthyes, Ottnangium, Burdigalium, Obere Meeresmolasse 1. Introduction the upfolding Alps in the South and the Bohemian Massif in the North. In the East, the Paratethys com- Most fossil remains of Neoselachians are fossil- prised the extant water bodies of the Black Sea, the ized teeth and dermal denticles, as the cartilaginous Caspian Sea and the Aral Sea. In the West, it encom- skeleton of Chondrichthyes is less prone for fossil- passed the southwestern German and Swiss parts ization (Maisey 2012). Nevertheless, highly special- of the North Alpine Basin and was connected to the ized dentitions of many shark and ray species allow Mediterranean basin and the Atlantic Ocean via the for a comparison of fossil teeth with extant taxa Rhone Basin (Pippèrr & Reichenbacher 2010). More- based on dental morphological characters. over, Pippèrr & Reichenbacher (2010) state that the Despite the presence of a number of deep-wa- collection site Neuhofener Beds likely had nutrient ter Neogene basins in the Alpine region, records of rich seawater and a significant fresh water inflow from Miocene deep-sea shark and ray species from the rivers draining surrounding mountains besides high central Paratethys are poorly known (Underwood & water circulation resulting in increasing oxygen levels Schlögl 2013) and insufficiently documented. Sam- in water bodies close to the basin floor. Besides these ples analyzed in this study were collected from the localized ecological conditions, the biodiversity was Paratethys, a series of elongate basins delimited by likely further influenced by potential migration routes Zitteliana 90 28 via connectivity to adjacent oceanic waters: the At- sediments of the southern German Molasse Basin lantic Ocean via the street of Gibraltar and the Rhone are part of the Paratethys. trench, connecting eventually to the North Sea, as The Neuhofener Beds sediments are represented well as the Indian Ocean via the Red Sea (Rögl 1998; by blue to grayish fine marls, including some thin Martini 1990). sandstone layers, which became visible in the up- In recent years, the Miocene deep-water chon- permost part of the outcrop. The diversity of fora- drichthyan fauna was documented in several pub- minifers found in the Neuhofener Beds is well-docu- lications as e.g. Vialle et al. (2011), Underwood & mented due to their outstanding preservation quality Schlögl (2013), Pollerspöck & Beaury (2014); never- (Hagn et al. 1981; Pippèrr & Reichenbacher 2010; theless, the information on distribution, composition, Pippèrr 2011), whilst the ostracod fauna is also well and occurrence of taxa is rather scarce compared to known (Witt 2009). Pippèrr & Reichenbacher (2010) shallow water assemblages. A comparison of previ- and Pippèrr (2011) suggest that the Neuhofener ously documented Miocene deep-sea neoselachian Beds represent an euhaline, deep-neritic basin fa- taxa with extant taxa occurring in the Mediterranean cies of the molasse with an estimated water depth Sea and the North East Atlantic reveals that several of > 100 m. taxa in the fossil record are documented based on only few specimens (e.g. genera Galeus (Underwood & Schlögl 2013) or Dalatias (Brisswalter 2009)), or are 3. Material and Methods completely absent (e.g. genera Apristurus, Somnio- sus, Oxynotus). In contrast to the low shark diversi- Sampling was conducted at three different sites in ties reported in the fossil record, multiple new extant the clay pit of the Neuhofener Beds from the location deep-water species have been described in recent Mitterdorf. For details on the samples, refer to Table years (White & Iglésias 2011; White et al. 2008; 1. All samples were dried and thereafter wetted in Yearsley et al. 2008; Ebert & Cailliet 2011; Ebert & a hydrogen peroxide solution (concentration 0,1% – Wilms 2013; Schaaf-Da Silva & Ebert 2006; Knuckey 1%). This was repeated two to three times until sed- et al. 2011; Ebert et al. 2011; Straube et al. 2011). iments were fully disaggregated. The residue was Most of these species are assigned to genera, which washed through 5 mm, 1 mm, 0.5 mm, and 0.25 mm are also reported in the fossil record based on their mesh. Fossils were recovered by eye using binocu- tooth morphologies. Here, we report on the diversity lars (WILD M3Z). In total, 441 partially fragmented of fossils found in the Neuhofener Beds and com- fossil elasmobranch teeth and 154 dermal denti- pare the documented deep-sea neoselachian fauna cles were recovered (Table 3). Only well-preserved with other fossil sampling sites as well as geograph- teeth were identified to family, genus or species level ically documented extant diversity compositions to depending on its preservation quality. Outstanding draw conclusions on geographic and ecological in- well-preserved fossils were cleaned in a 2% hydro- fluences which may have shaped the diversity of the gen peroxide solution and ultrasonic sound (MEC Neuhofener Beds. 300 VAP, MOTOR, Jewelry Cleaner). These samples were mounted on Scanning elec- tron microscopy (SEM) stubs and prepared for SEM 2. Sampling site imaging using a Polaron E5100 SEM coating system. Subsequently, SEM images were taken using a LEO The material described herein was collected at 1430 VP (Carl Zeiss, Jena). GIMP2 (https://www. 13.28°E, 48.49°N (WGS84, location Mitterdorf, be- gimp.org/) was used to excise images and standard- tween Fürstenzell and Schmidham, Bavaria, Germa- ize a scale for figure plates. For the identification of ny) and is the site of recently installed clay works taxa, morphological characters described in Cap- (Fig. 1). The exposed horizons of the Neuhofener petta (2012) were used. Measurements were taken Beds are part of the Upper Marine Molasse and are using the width and height of teeth at homologous assigned to the Lower Ottnangian (= Middle Burdi- landmark sites. Damaged teeth are subsequently galian) (Hagn et al. 1981; Unger 1984; Pippèrr & Rei- marked with the symbol “+”. chenbacher 2010; Pippèrr 2011). These fully marine Table 1: Details on sampling sites. SAMPLE (FP) WEIGHT (KG) LOcatiON DESCRIPTION mixed sediments intended for transportation; July 1 70 13.28°E, 48.49°N 2013 taken at location of 1st depletion site; including ca. 2A/ 2B 315 13.28°E, 48.49°N 15 kg sediment from a fine sand deposit (FP2B); June 2014 3 300 13.28°E, 48.49°N taken at bottom of clay pit, August 2014 29 Zitteliana 90 Figure 1: Geographical location of sampling site. This published work and the nomenclatural acts it To survey extant and fossil deep-sea elasmo- contains have been registered in ZooBank, the on- branch diversity, data from peer-reviewed articles line registration system for the ICZN. The LSID (Life dealing with the diversity of deep-sea elasmobranchs Science Identifier) for this publication is: http://zoo- on genus level was collected to create a presence/ bank.org/References/AF040A11-D0E8-4403-B00A- absence matrix of taxa at different