200
Abstracts
inated by semi-infaunal (bakevelliids, modiolines, pinnids) and epifaunal (resp. epibyssate) suspension-feeding bivalves (inoceramids, oysters, pectinids, limids). Deepinfaunal bivalves are missing. Deposit-feeding biota are comparably rare, possibly related to the organic-poor character of the substrate (mature quartz sand). The frequent occurrences of articulated bivalves suggest episodic rapid burial, most probably by tempestites. A current-influenced, well-oxygenated and nutrient-rich environment between the fair-weather and storm-wave bases is inferred for the finegrained sediments of the Oberhäslich Formation.
S15 – The Langenberg-Quarry in Oker – A special window into the terrestrial Late Jurassic of Northern Germany Wings O. * 1,2
*E-mail:
[email protected] Museum für Naturkunde Berlin, Invalidenstr. 43, 10115 Berlin, Germany 2 Niedersächsisches Landesmuseum Hannover, WillyBrandt-Allee 5, 30169 Hannover, Germany 1
The Langenberg Quarry in Oker, Lower Saxony, is a classic and biostratigraphically well dated outcrop of late Oxfordian to late Kimmeridgian marine strata. Paleogeographically, it is located in the Lower Saxony Basin that covered much of northern Germany in Late Jurassic and Early Cretaceous times and that was surrounded by several large paleo-islands. The Langenberg Quarry is also a very important locality for terrestrial vertebrates, which must have been transported into the basin from a nearby paleo-island. Dwarfing of the largest animal in the fauna, the basal macronarian sauropod dinosaur Europasaurus holgeri, has been interpreted as resulting from resource limitations in the island habitat. In particular beds 56, 73, and 83 of the stratigraphy of Fischer yielded terrestrial vertebrates, while most other beds contain a purely marine vertebrate fauna. The composition of carbonates and marls as well as the invertebrate fauna recorded changes in water depth, but there is no sedimentological evidence for subaerial exposure; although one horizon has preserved theropod and possibly also small sauropod tracks. Beside the abundant and excellently preserved Europasaurus material, three bones of a diplodocid sauropod (possibly also dwarfed), and very few theropod bones, the Langenberg Quarry yielded additional exceptional material of terrestrial non-dinosaurian vertebrates. This includes the three-dimensionally preserved articulated skeleton of a small pterosaur, which has been described as the first dsungaripterid from the Kimmeridgian of Germany, and the skeletons of a new taxon of the small nonmarine atoposaurid crocodilian Theriosuchus.
A new excavation in the most promising layers is scheduled for August and September 2012. It will help to understand the taphonomy and the paleoecology of the terrestrial vertebrates. It is expected that the planned extensive screenwashing will vastly expand the number of known taxa from the quarry.
S17 – The enigmatic bovid Duboisia santeng (EarlyMid. Pleistocene, Java): a multiproxy approach to its palaeoecology Winkler D. E.1* , R. Rozzi2 & E. Schulz1 *E-mail:
[email protected] Biocenter Grindel & Zoological Museum, University of Hamburg, Martin-Luther-King-Platz 3, Hamburg, Germany 2 Dipartimento di Scienze della Terra, Università di Roma“La Sapienza”, Piazzale Aldo Moro, 5, Roma, Italy 1
During the Pleistocene, faunal exchanges between the Sunda Island Java and the East-Asian mainland occur via land bridges, permitting faunal elements of Indo-Chinese origin to enter Java. Hence, most Javanese mammalian taxa are similar if not identical to their mainland relatives. Among the four Javanese bovids, Duboisia santeng, however, has been regarded as a typical endemic species due to its small size. So far, except from being obviously smaller than its relatives, nothing is known about Duboisia’s dietary or habitat adaptations. The vegetation on Java was influenced by climatic oscillations during the mid-Pleistocene and hence provided diverse habitats including open grasslands, seasonal forests, mangroves and swamps, which could put alternating selective pressures on D. santeng. We test the hypothesis that Duboisia santeng’s small size was an adaptation to occupying a specialized niche in a closed environment. We apply a multiproxy approach for palaeohabitat reconstruction to better understand the ecology of Duboisia santeng: First we reconstruct palaeodiet using 2D-mesowear for a long term and 3D-surface texture analysis for a short term signal. Secondly we perform an ecomorphological reconstruction by morphometric analysis of postcranial elements (six femoral and eight astragali variables) to match diet with habitat preferences and reconstruct mean body mass from 26 allometric equations based on cranial, dental or long bone dimensions. The mesowear signature of Dubosia santeng is characterized by high reliefs with sharp cusps (70%), a few round cusps (15%) and low reliefs with round cusps (15%). This high frequency of sharp cusps in combination with high relief and a lack of blunt cusps are characteristic of an attrition dominated browsing diet in general. Enamel surface textures of D. santeng have lower values for density of peaks (Spd) and material volume (Vm) compared to extant browsers. The values for mean surface roughness
Abstracts
(Sa) and core material volume (Vmc) lie in between extant browser and grazer. This is indicative of abrasive components in the diet. Considering mesowear as long term and surface textures as a short term dietary signature we conclude that D. santeng was neither a grazer nor a fruit browser, but a leaf browser with some endogenous or exogenous abrasive components in its diet. Its estimated mean body mass is 54 kg. The 14 variables taken on femora and astragali placed Duboisia among extant forest and light-cover dwellers, which is in accordance with a browsing diet. Thus, we infer that Duboisia inhabited forests or semi-closed habitats in the heterogeneous landscape of mid-Pleistocene Java, while the larger bovids like the extinct water buffalo Bubalus palaeokerabau are supposed to have lived in open landscapes and swamps.
S17 – A case study of seasonal, sexual and ontogenetic divergence in the feeding behaviour of the moose (Alces alces Linné, 1758) Winkler D. E.1* & T. M. Kaiser1 *E-mail:
[email protected] Biocenter Grindel and Zoological Museum, University of Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
1
We examine differential feeding behaviour in a sexual dimorphic ungulate, the moose (Alces alces Linné, 1758). Due to different energetic requirements of males and females, as well as between ontogenetic stages (juvenile/ subadult vs. adult), we expect individuals to select forage according to their needs: either for quality or quantity. The selectivity should be less pronounced in winter as forage then is less abundant. To determine forage quality in terms of the amount of abrasive components, we apply the mesowear method of dietary evaluation. We find that male and female moose of all age classes have a similar winter diet. In summer, both young and adult females feed on more abrasive food than males. Males of all age classes have to cope with similar levels of abrasives in their diet. This would be explained by differential energetic needs in males and females. While males can afford to feed selectively, females cannot. Females regularly experience periods of high energetic demands during lactation, in which they also need to exploit more abrasive food sources, as compared to males.
S9 – Feeding behaviour of the Triassic plagiosaurid Gerrothorax – a case study of aquatic feeding in temnospondyls Witzmann F.1* & R. R. Schoch2
201
*E-mail:
[email protected] Museum für Naturkunde, Leibniz-Institut für Evolutionsund Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Invalidenstr. 43, 10115 Berlin, Germany 2 Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany 1
The Middle to Late Triassic plagiosaurid Gerrothorax is a highly derived, gill-breathing temnospondyl characterized by its broad, short-snouted skull and a generally flattened morphology. Regarding the aberrant morphology of Gerrothorax, the question of how this temnospondyl fed in water has been widely discussed in the past decades, but no integrated picture of mouth opening and hyobranchial movement has been provided so far. In the present study, the cranial and hyobranchial muscles of Gerrothorax were reconstructed as far as possible based on direct evidence (spatial limitations, ossified muscle insertion sites on skull, mandible and hyobranchium) and on phylogenetic reasoning (Extant Phylogenetic Bracket, with extant basal actinopterygians, sarcopterygian fishes and salamanders as bracketing taxa). Inferring from skeletal anatomy and the presumed associated muscles, the feeding behaviour of Gerrothorax can be reconstructed as follows. The flattened morphology, the short limbs and the heavily built skeleton strongly suggest that Gerrothorax was a bottomdwelling ambush predator. However, if Gerrothorax had rested on the bottom and had solely raised its head during prey capture as previously assumed, there would have been by far not enough interspace between skull and pectoral girdle to retract the hyobranchial apparatus and to increase the size of the buccal cavity for suction feeding. Furthermore, the orientation of the muscle scars on the postglenoid area of the mandible indicates that a portion of the depressor mandibulae extended posterodorsally on the trunk behind the skull. This suggests that the depressor was indeed used for lowering the mandible and not to raise the skull as earlier supposed, and implies that the skull including the mandible must have been lifted off the ground during prey capture. It can thus be assumed that Gerrothorax raised the head towards the prey with the jaws still closed. Then the mouth started to open rapidly. Analogous to the extant bracketing taxa, this was caused by action of the strong epaxial muscles (further elevation of the head) and the depressor mandibulae and rectus cervicis (lowering of the mandible). During mouth opening, the action of the rectus cervicis muscle also rotated the hyobranchial apparatus ventrally and caudally, thus expanding the buccal cavity and causing the inflow of water with the prey through the mouth opening. The strongly developed depressor mandibulae and rectus cervicis, as well as the well ossified, large quadrate-articular joint suggest that this action occurred rapidly and that powerful suction was generated. Similar to the jaw opening muscles, also the jaw adductors were well developed and enabled a rapid closure of the mouth. In contrast to extant salamander larvae and most extant actinopterygians (tele-
