Fossil Record最新文献

A new stem-orthopteran insect assignable to the – traditional – genus and the – cladotypic-defined – taxon Miamia Dana, 1864 is described based on abundant material collected from the Xiaheyan locality (Ningxia, China; Early Pennsylvanian). Intra-specific wing venation variability in Miamia maimai n. sp. is appreciated based on wing pairs of single individuals, and on a complete series of conditions. Rare variants are reported. Details of head and leg morphology are documented: the new species possesses a five-segmented tarsus provided with paired claws and arolium, and labial palps with at least four segments, probably five. The nomenclatural section is conducted under the cladotypic nomenclatural procedure, but in a way largely consistent with the traditional usage. This experiment demonstrates that a combination composed of a ‘genus level-taxon’ name previously associated with a definition and type material (e.g. Miamia), a specific epithet (e.g. maimai), and authorship information (e.g. Béthoux et al. 2012), with further mention to ‘Miamia maimai ’ or ‘M. maimai ’, provides a suitable reference to the species under all nomenclatural procedures, including the traditional one. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We document the sporophyte of the extinct Frullania varians based on an inclusion in Late Oligocene Bitterfeld amber from Germany. The sporophyte consists of a short, ca. 45 µm thick seta that exceeds the perianth only slightly; the elongate-ovate, acute valves of the opened capsule are about 225 µm long, curved backwards and consist of an epidermal and an internal layer. Cell walls of both layers possess nodulose trigones. Several trumpet-shaped, unispiral elaters are fixed to the upper third of the internal valve layer. They have a length of ca. 150 µm and a diameter of 15–18 µm. A subglobose structure of 19 µm diameter is interpreted as a degraded spore. Fossil elaters and spores as well as capsule wall details of Frullaniaceae are described for the first time. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In the central Anti-Atlas (Morocco), the Early Ordovician succession consists of about 1000 m of fossiliferous argillites and siltstones. The Upper Fezouata Formation (Floian) contains a comparatively rich and abundant cephalopod association. A small collection of these cephalopods is described herein for the first time. The cephalopods are interpreted as autochthonous or parautochthonous, representing a fauna, which originally lived nektobenthically in the open water above the sediments or related to the sea bottom. The cephalopod associations of the Upper Fezouata Formation are similar to other contemporaneous assemblages known from higher palaeolatitudes and associated with deeper depositional settings and in siliciclastically dominated deposits. They are composed almost exclusively of slender orthocones, in this case predominantly of Destombesiceras zagorense n. gen., n. sp., which is interpreted as an early discosorid. Bathmoceras australe Teichert, 1939 and Bathmoceras taichoutense n. sp. from the Upper Fezouata Formation are at present the earliest unambiguous occurrences of bathmocerid cephalopods. Epizoans on the shell of a specimen of Rioceras are the earliest evidence of bryozoans growing as potential hitchhikers on cephalopod shells, indicating an early exploitation of a pseudoplanktonic lifestyle in this phylum. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A new harvestman (Arachnida: Opiliones) from Baltic amber (Palaeogene: Eocene; ca. 44–49 Ma) is described as Piankhi steineri n. gen., n. sp. This enigmatic fossil expresses long, slender pedipalps without a tarsal claw, which is characteristic for the suborder Dyspnoi. The chelicerae are notably enlarged and the dorsal body surface is formed from a carapace with a separate prosomatic tergite (metapeltidium), plus a large opisthosomal scute (or scutum parvum). However these characters, combined with the distinctly spiny limbs and further rows of spines across the fossil's opisthosoma, have no parallel among the modern dyspnoid harvestmen that we are aware of. The fossil resolves features reminiscent of modern members of the dyspnoid families Ceratolasmatidae, Nipponopsalididae, Ischyropsalididae and Sabaconidae, but does not show unequivocal apomorphies of any one particular family. We must entertain the possibility that this is an extinct body plan from the Eocene of north-central Europe, and we tentatively refer the fossil to a new genus in an unresolved position among the Ischyropsalidoidea (Dyspnoi). An amorphous triangular structure behind the anal region is assumed to be faecal matter, rather than part of the original anatomy. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A new neopterygian fish, Voelklichthys comitatus n. gen. n. sp., is described. The fish was found during the preparation of the theropod Juravenator starki Göhlich & Chiappe, 2006 in the same rock. The fish possesses numerous autapomorphies. The combination of autapomorphies is unique among Jurassic fishes and makes its taxonomic assignment difficult. The following characters are few examples demonstrating some of the peculiarities of the fish: The fish is small, oblong-shaped and has a large triangular head that is deeper than long; deepest point is at the level of the postparietal bone [parietal of traditional terminology] and the ventral end of the cleithrum. The skull roof is almost vertically oriented, with a strongly ossified and developed antero-dorsal orbital margin. Premaxilla and dentary possess very small conical teeth. The opercular apparatus is markedly narrow and deep. A clavicle is present. Both dorsal and ventral postcleithra are almost as deep as the maximum depth of the head; the dorsal postcleithrum is two times deeper than the ventral one. The vertebral centra are of arcocentral-type formed mainly by the development of the dorsal arcocentra. Pectoral and pelvic fins possess long rays that extend onto the pelvic and anal fins, respectively, whereas the rays of the dorsal and anal fins extend onto the caudal fin. The fish is interpreted as a macrosemiiform because it presents two of the three synapomorphies of the group (e.g., an incomplete circumorbital ring because the lateral edge of parietal bone [frontal of traditional terminology] makes up part of orbital margin and absence of a supramaxillary bone). The third macrosemiiform synapomorphy cannot be determined in the new fish because the coronoid bones and their dentition are not observed due to condition of preservation. The new fish shares a few characters with members of the families Macrosemiidae and the Uarbryichthyidae but lacks others so that presently, we place it in a family indeterminate within Macrosemiiformes. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Changes in body size have been the subject of numerous palaeontological and neontological studies, but despite several general postulated “rules”, the underlying processes controlling them are still incompletely understood, and their broad applicability is debated. Here we utilise morphological and ecological data from the Jurassic marine bivalve Chlamys textoria (Schlotheim, 1820) to analyse spatial and temporal trends in body size and ornamentation. We find: (1) fluctuations in body size during the Jurassic and no support for Cope's rule (the tendency to increase body size over geological time within an individual lineage); (2) a gradual increase in the average height to length ratio of the valves during the Jurassic. In the absence of any obvious adaptive advantage we suggest genetic drift as the causal mechanism; (3) a significantly larger mean body size in mid-palaeolatitudes than in the Jurassic tropics, providing evidence for the validity of Bergmann's rule (the assertion that body mass increases with latitude); and (4) a complex relationship between the number of plicae and the environment, which we explain as an improvement towards camouflaging the shell. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Seit einigen Jahren werden die Funde großer Wirbeltiere aus der oberjurassischen Fossilfundstelle Tendaguru in Tansania durch diverse Mikrovertebraten ergänzt. Diese konnten durch gezieltes Schlämmen von Sedimentmaterial gewonnen werden (Heinrich, mündl. Mitt.), das während der Tendaguru-Expeditionen von 1908 bis 1913 gewonnen wurde.

Durch ein isoliertes Kieferfragment kann der Erstnachweis eines paramacellodiden Lacertiliers im Afrika südlich des Äquators (bei 10° südlicher Breite) geführt werden. Dieser Fund rundet das Bild der sehr weiten Verbreitung dieser erfolgreichen mesozoischen Echsengruppe ab.

Recently, there have been additional microvertebrate finds within the known macrovertebrate fauna of the Upper Jurassic locality Tendaguru in Tanzania. This resulted from the processing of sediment samples, which had been collected during the Tendaguru Expeditions in between 1908 and 1913 (Heinrich, pers. Comm.).

An isolated jaw fragment from a paramacellodid lizard is the first record of this family within the African continent below the equator (10° degrees Southern latitude). The occurence of this successful Mesozoic lizard group in Tendaguru reflects a greater global distribution than known to date.

Abgesehen von einem unreifen Araukarienzapfen, der 1927 von Gothan kurz beschrieben wurde, werden erstmalig Pflanzenreste aus den Jura-Kreide-Grenzschichten des Tendaguru bekannt gemacht. Verkieselte Hölzer vor allem aus kreidezeitlichen Schichtabschnitten repräsentieren die für den Jura üblichen Koniferengruppen wie Taxodiaceae, Cupressaceae und Taxaceae. Daneben konnten Ginkgoaceae nachgewiesen werden. Fusit ist nicht selten, meist aber sehr schlecht erhalten, bis auf ein Stück, das die Merkmale einer wahrscheinlich neuen Art von Glyptostroboxylon, einer Taxodiacee, zeigt. Naturmazerate von Kutikulen sind in den mittleren Saurier-Mergeln (tieferes Kimmeridge) häufig und können möglicherweise Ginkgophyten des Baiera/Sphenobaiera-Typs zugerechnet werden. Damit scheint die Flora von Tendaguru auf den ersten Blick von Gymnospermen extrem stark dominiert zu sein. Diese Dominanz ist wahrscheinlich auf taphonomische Prozesse und auf die selektive Probennahme während der Grabungsexpedition in den Jahren 1909–1913 zurückzuführen. So erscheinen neue Profilaufnahmen im Gelände unumgänglich, um ein differenzierteres Bild der jurassisch-kretazischen Flora des östlichen Afrika — die die Ernährungsgrundlage der meisten Dinosaurier vom Tendaguru bildete — zu entwickeln und phytogeographische Beziehungen genauer fassen zu können.

Little is known about the Jurassic flora of East Africa. Therefore a preliminary account on plant remains from the well-known „Saurierlagerstätte”︁ of Tendaguru is presented. Specimens of silicified wood represent typical conifers, such as Taxodiaceae, Cupressaceae and Taxaceae, but also demonstrate the presence of Ginkgoales. Fusite is very common, but mostly not well preserved, except for one specimen which shows the characteristics of possibly a new species of the Taxodiacean genus Glyptostroboxylon. Natural macerated cuticules are abundant in the „middle Saurier-Mergel”︁ (Lower Kimmeridgian) and they at least in part seem to belong to Ginkgophytaleans of the Baiera/Sphenobaiera-group. At first glance the composition of the flora of Tendaguru seems to be biased towards a predominance of Gymnosperms. This is not only a result of taphonomical processes, but also of selective sampling in 1909–1913. Preliminary observations support the opinion that further field work must be carried out if we would like to obtain a clearer „picture”︁ of the Jurassic-Cretaceous flora that formed the diet of herbivorous dinosaurs.

Speeds of walking dinosaurs that left fossil trackways have been estimated using the stride length times natural pendulum frequency of the limbs. In a detailed analysis of limb movements in walking Asian elephants and giraffes, however, distinct differences between actual limb movements and the predicted limb movements using only gravity as driving force were observed. Additionally, stride frequency was highly variable. Swing time was fairly constant, but especially at high walking speeds, much shorter than half the natural pendulum period. An analysis of hip and shoulder movements during walking showed that limb swinging was influenced by accelerations of hip and shoulder joints especially at high walking speeds. These results suggest an economical fast walking mechanism that could have been utilised by large dinosaurs to increase maximum speeds of locomotion. These findings throw new light on the dynamics of large vertebrates and can be used to improve speed estimates in large dinosaurs.

Geschwindigkeiten gehender Dinosaurier, die fossile Fährten hinterlassen haben, wurden als Produkt aus Schrittlänge und natürlicher Pendelfrequenz der Beine abgeschätzt. Eine detaillierte Analyse der Beinbewegungen von gehenden Asiatischen Elefanten und Giraffen offenbarte allerdings klare Unterschiede zwischen den tatsächlichen Extremitätenbewegungen und den Bewegungen, die zu erwarten wären, wenn die Gravitation die einzige treibende Kraft darstellte. Zudem erwies sich die Schrittfrequenz als hochgradig variabel. Die Schwingzeit der Gliedmaßen war recht konstant, aber besonders bei hohen Gehgeschwindigkeiten viel kürzer als die halbe natürliche Pendelperiode der Extremitäten. Eine Analyse der Bewegungen der Hüft- und Schultergelenke während des Gehens zeigte, daß das Schwingen der Gliedmaßen durch Beschleunigungen dieser Gelenke beeinflußt wurde, insbesondere bei hohen Gehgeschwindigkeiten. Die Resultate legen einen ökonomischen Mechanismus für schnelles Gehen nahe, der von großen Dinosauriern zur Erhöhung der Höchstgeschwindigkeiten eingesetzt worden sein könnte. Die Ergebnisse werfen neues Licht auf die Dynamik großer Wirbeltiere. Sie können zu Verbesserungen in den Schätzungen der Fortbewegungsgeschwindigkeiten großer Dinosaurier eingesetzt werden.

Comparison of avian and crocodylian lung structure suggests a basic archosaurian structural type, consisting of four rows of chambers that radiate independently from an intrapulmonary bronchus. The later structure is cartilage-reinforced cranially. Caudally, the cartilage reinforcement diminishes and the radiating pattern of tubular chambers becomes irregular. The presence of extensive pneumatic spaces in the dorsal vertebrae combined with the extremely large size of Brachiosaurus suggests that the dorsal margin of the lungs was strongly attached to the body wall, thus restricting lung inflation in this region. By analogy with similarly structured testudine lungs, it is highly probable that the ventral part of the very large and cavernous lungs consisted of sac-like chambers, which acted as air reservoirs and also ventilated the gas exchange tissue, which was concentrated dorsally.

Die Strukturen der Vogel- und der Krokodillunge deuten auf einen basalen Bauplan der Archosaurierlunge hin, der aus vier Reihen von Kammern besteht, die von einem intrapulmonalen Bronchus entspringen. Dieser ist cranial knorpelig verstärkt. Caudal vermindert sich die knorpelige Verstärkung und das Verteilungsmuster der Kammern wird ungleichmäßig. Die Anwesenheit von pneumatischen Räumen in den Wirbelkörpern und die extreme Größe von Brachiosaurus deuten daraufhin, daß der dorsale Bereich der Lunge mit der Körperwand verbunden war. Dies schränkte die Belüftung der Lunge in dieser Region ein. In Analogie zu den ähnlich strukturierten Schildkrötenlungen ist es höchst wahrscheinlich, daß der ventrale Teil der sehr großen Lungen aus sackartigen Kammern bestand, die als Luftreservoir dienten und das dorsal liegende Gasaustauschgewebe ventilierten.