4 research outputs found
Eocene relatives of cod icefishes (Perciformes: Notothenioidei) from Seymour Island, Antarctica
Fragmentary skull bones and vertebra from the Upper Eocene La Meseta Formation on Seymour (Marambio) Island, Antarctic Peninsula have been described as gadiform fishes, informally named “Mesetaichthys”. Here we describe jaws as Mesetaichthys jerzmanskae n. g. and n. sp., and refer this taxon to the perciform suborder Notothenioidei. This group is almost unknown as fossils. Similarities to the living, ‘primitive’ nototheniid Dissostichus eleginoides are indicated in the dentition. Gadiform evolution in the Paleocene-Eocene, and the possibility of a correlation between the origin and evolution of notothenioids in connection with the deterioration of the climate in Antarctica during the Late Eocene-Oligocene is discussed
The trace fossil Lepidenteron lewesiensis: a taphonomic window on diversity of Late Cretaceous fishes
The trace fossil Lepidenteron lewesiensis (Mantell 1822) provides an exceptional taphonomic window to diversity of fishes as shown for the Upper Cretaceous of Poland, in the Middle Turonian–Lower Maastrichtian deposits of the Opole Trough, Miechów Trough, Mazury-Podlasie Homocline, and SE part of the Border Synclinorium. Lepidenteron lewesiensis is an unbranched burrow lined with small fish scales and bones, without a constructed wall. It contains scales, vertebrae, and bones of the head belonging to ten taxa of teleostean fishes: two undetermined teleosteans, six undetermined Clupeocephala, one Dercetidae, and one undetermined euteleostean. The preservation of fish remains suggests that fishes were pulled down into the burrow by an animal, probably by eunicid polychaetes.Das Spurenfossil Lepidenteron lewesiensis (Mantell 1822) ermöglicht einen biostratinomischen Einblick in die Diversität von Fischen, wie Fossilmaterial aus der Oberkreide von Polen zeigt. Es stammt aus dem Mittelturonium bis Untermaastrichtium des südöstlichen Abschnittes der Grenz-Synklinale, dem Opolen-Trog, dem Miechów-Trog und der Masuren-Podlachien-Homoklinale. L. lewesiensis ist ein unverzweigter Grabgang ohne ausgekleidete Wände, dessen Ränder von kleinen Fischschuppen und—knochen gebildet werden. Diese setzen sich aus Schuppen, Wirbel und Schädelknochen von zehn Teleostei-Taxa zusammen und zwar aus zwei unbestimmte Teleosteer, sechs unbestimmten Clupeocephala, einem Dercetidae und einem unbestimmten Euteleostei. Die Erhaltung der Fischüberreste deutet darauf hin, dass die Fische von einem Tier, wahrscheinlich einem Polychaeten der Familie Eunicidae, in den Bau gezogen wurden.We are very grateful to Dr. Lionel Cavin (Geneva) and the anonymous reviewer for constructive comments on an earlier version of the manuscript. Additional support was provided by the Jagiellonian University (DS funds), National Science Center (Grant Number: PRO-2011/01/N/ST10/07717), and the Laboratory of Geology (University of Lodz) BSt Grant No. 560/844. We are grateful to Dr. Johann Egger (Wien) and Kilian Eichenseer M.Sc. (Erlangen) for help with translating the abstract into German. We are grateful to Dr. Ursula Göhlich (Wien) for access to the Dercetis specimen
Dinoflagellate cyst stratigraphy of the Popiele Member and Menilite Formation in the Boryslav-Pokuttya Nappe (Aksmanice, SE Poland)
In the Paratethys Sea, isolation, the development of anoxia and stratification of the water column resulted in deposition of organic-rich sediments. In the Western Carpathians (Central Paratethys) these sediments now lie within the Menilite Formation. Whereas the Eocene-Oligocene transition has been studied in the Western Carpathians and is documented by dinoflagellate cyst assemblages, the dinoflagellate cyst stratigraphy of the Menilite Formation members has been uncertain. The Popiele Member and the Menilite Formation exposed at Aksmanice (Boryslav-Pokuttya Nappe, Western Outer Carpathians) reflect palaeogeographic changes at the beginning of the Oligocene. These previously studied deposits have been assigned to lithostratigraphic units, though without biostratigraphic documentation. The age of the Menilite Fm. in the Carpathian sedimentary succession is particularly interesting due to the diachronous character of the facies development. In this study we provide biostratigraphic data based on well-preserved organic-walled dinoflagellate cyst assemblages. The marker taxa recovered indicate a Rupelian age (Early Oligocene) for the Menilite Fm. A different assemblage occurs in the Popiele Member underlying the Menilite Fm. Here, the dinoflagellate cysts are more diverse and abundant, and represented by typical Eocene taxa attributed to Areosphaeridium spp. and Charlesdowniea spp. The Popiele Member may be assigned to the Priabonian (Late Eocene)
Anatomy of the coracoid and diversity of the Procellariiformes (Aves) in the Oligocene of Europe
Two European species of the Diomedeoididae, an extinct family of procellariiform (tube-nose) birds, have hitherto been distinguished primarily by size of their limb bones. Here, we describe an Early Oligocene (Rupelian) procellariifom coracoid that in all probability represents the larger species, Diomedeoides lipsiensis, and compare it to the coracoids of smaller diomedeoidids and extant procellariiforms. Using multivariate (Principal Component Analysis) and univariate analyses, we demonstrate that nearly all measurements are heavily size dependent, which makes the proportions and some other shape characters of little use as phylogenetic markers. Among eight measurements, the coracoid corpus width shows the highest correlation (higher than corpus depth) with body mass, permitting a precise calculation of over twofold difference in body mass between D. lipsiensis and smaller species. Among 16 qualitative characters analysed, the majority proved too variable to be used as markers of interfamily relationships and only 2–3, the ventral intermuscular line, sternocoracoid articulation (divided vs. undivided), and, with reservations, epimarginal crest vary consistently between the families. By far the most variable is the acrocoracoid process that tends to be deeper (more elongate dorsoventrally) in larger petrels but not in the albatrosses. However, the detailed shapes of the acrocoracoid heads are highly genus specific and suggest a genus-level diversity among the Diomedeoididae from the Oligocene of Europe. The common features of the diomedeoidid coracoids are best interpreted as plesiomorphies, which accounts for some similarities to the Oceanitinae (that are probably basal among the crown-group procellariiforms). The evidence from the coracoid is consistent with a stem-group position of the Diomedeoididae as previously proposed by others. We emphasize the need of a group-specific character analysis, primarily of allometries and levels of character variation, prior to a phylogenetic reconstruction