Palaeontographica Abteilung a -Stuttgart-

Published by E Schweizerbart Science Publishers
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A new mesosuchian crocoddian from the Nova Olinda Member of the Crato Formation (Lower Cretaceous, Aptian) of north-eastern Brazil is described. Susisuchus anatoceps gen. et sp. nov. is the first crocodillan to be reported from this formation. It is represented by an incomplete, partially articulated skeleton: the skull and mandible, partial postcranial axial skeleton, forelimbs and portions of the osteodermal skeleton. Preservation of soft tissues includes the skin surrounding both forelimbs and the digits of the right hand. The state of preservation of the specimen suggests that it was incorporated into the basin as a desiccated carcass. Susisuchus anatoceps is one of the oldest crocodilians with a eusuchian-type dorsal shield, comprising a tetraserial paravertebral shield and, either side of this, two sagittal rows of accessory osteoderms. It also possesses amphicoelous thoracic, lumbar and caudal vertebrae. This combination of postcranial features have never before been seen in a crocodilian and warrant the erection of a new family within Mesosuchia: Susisuchidae. Taxonomically, S. anatoceps is similar to a number of Lower Cretaceous mesosuchians previously considered to have given rise to eusuchians, most notably the Glen Rose crocodilian and a new, but as yet undescribed crocodillan from the Lower Cretaceous Winton Formation of western Queensland, Australia. Preliminary preparation of the Winton crocodilian indicates that it may belong to Susisuchidae, supporting the hypotheses of interchange between the vertebrate faunas of South America and Australia during the Lower Cretaceous.
Measurements of upper tooth series (occlusal lengths) 
Measurements of mandibles
Measurements of D. pikermiensis skulls
We describe the remains of Rhinocerotidae from about 10 Late Miocene localities of Bulgaria, the main ones being Kalimantsi and Hadjidimovo, and the newly discovered site of Strumyani. At least seven species are represented, mostly by cranial elements. A skull is assigned to Chilotherium kiliasi, a species for which a new sub-genus, Eochilotherium, is established. Some fragmentary remains are referred to Ch. (Chilotherium), which reaches in Bulgaria the westernmost limit of its range. Acerorhinus is well represented at Kalimantsi, but this genus probably deserves revision. An unexpected discovery is that of Brachypotherium at Ahmatovo, its latest known occurrence in Europe. The horned rhinos, Ceratotherium and Dihoplus, co-occur at two localities. This relatively great diversity points to a variety of environments, as it is unlikely that the main fossil faunas are very different in age. It also reflects the geographic position of Bulgaria, where the ranges of the mainly Asiatic Chilotherium, of the Pontic Acerorhinus and of the Balkano-Iranian Ceratotherium overlap, in addition to a possible immigration of Brachypotherium from Africa into Europe.
In contrast to the global trend of mid-latitude drying in Late Neogene, North China appears to have experienced an increase in humidity during the latest Miocene, the Baodean land mammal age sensu stricto. This "favourable oasis" in time and space had a strong influence on the evolution of the herbivorous land mammals of the region. The locally improved conditions first caused an influx of immigrants from several directions and later the development of endemic taxa from both native and immigrant stock. Lack of published data hinders a study of the effect on the mammal fauna when the climate became dry, a process well underway by the Middle Pliocene, but ultimately the effects of the Baodean exception were erased and North China joined the Palaearctic faunal province. We hypothesise that the apparently high diversity and low endemism seen in the North Chinese land mammal faunas of the latest Miocene can be explained by a Koenigswaldian model, in which two separate faunal assemblages cyclically alternate and mingle in a transitional zone.
The determination of the palaeoecological conditions of the Perivolaki fauna is given in the present article using various methods. The faunal diversity of Perivolaki is studied using several indices (Simpson, Shannon-Wiener, Whittaker) and indicates a homogeneous and equilibrated fauna with normal taxa distribution. The dental microwear analysis of the ungulates (Bovidae, Equidae) provided data about the feeding preferences of the identified taxa and in comparison to those from other localities a bushy-shruby-woody palaeoenvironment is possible for Perivolaki. The faunal composition of Perivolaki fauna suggests the dominance of the bovids and equids, indicating a relatively open environment. The comparison of the faunal composition of the Perivolaki fauna with those from various European localities, as well as with the recent ones from certain environments, using multivariate analysis suggests that the Perivolaki fauna matches to the recent open and dry ones. The faunal similarity is also studied using the Simpson's index, indicating close relations of the Perivolaki fauna to those of Axios valley than to those of Southern Greece (Pikermi, Halmyropotamos), Eastern Aegean Sea (Samos) and Asia Minor. All the available results from this study suggest for Perivolaki an open bushy-woody environment with grass undergrowth.
The fossil snake described from the uppermost Oligocene of Rott near Bonn (Germany) as Tropidonotus atavus by VON MEYER (1855) is redescribed as a type species of the new extinct genus Rottophis. It was a member of the family Boidae, but the existing material does not permit a more precise systematic allocation; most likely Rottophis either belonged to the living subfamily Boinae or it constituted a distinct extinct lineage of boid snakes.
Two localities in the Boskovice Furrow in Moravia (Czech Republic) have produced new, three-dimensional material of early ontogenetic stages of the Lower Permian tetrapod Discosauriscus austriacus (MAKOWSKY 1876). The sensory grooves of the lateral line system are well developed. They form the infraorbital, supraorbital, postotic, cephalic division of main, jugal and supratemporal commissural sensory grooves. The pit-lines are present on frontal, parietal, postpanetal, tabular, supratemporal and intertemporal, and represent the first records of these structures in tetrapods. The morphology and position of the pit-lines in Discosauriscus are similar to those present in the bones of skull roof in osteolepiform fishes. The homologization of the pit-lines of Discosauriscus and osteolepiforms indicates that the bones which enclose the pineal foramen in osteolepiforms are the frontals and not the parietals. The same is true also for the Devonian tetrapods Ichthyostega and Acanthostega. The identification of homologous exocranial bones in Discosauriscus and osteolepiforms permits determination of the primitive and derived characters for tetrapods. Hence, the parietal - tabular contact ("anthracosaur condition") is primitive for tetrapods. The positional relationships of the lateral line system in Discosauriscus provides further evidence for the origin of tetrapods (at least the reptiliomorphs) from osteolepiforms.
The ammonites assigned to the family Acanthoceratidae de Grossouvre, 1894, from the Wiedmann (Tübingen, Germany) and Goy, Carretero and Meléndez (Madrid, Spain) collections obtained from the Lower Turonian of the Iberian Trough have been revised. New specimens of the species Spathites (Jeanrogericeras) tavense (Faraud, 1940), S. (J.) saenzi (Wiedmann, 1960), S. (J.) postsaenzi (Wiedmann, 1960), S. (J.) obliquus (Karrenberg, 1935), S. (J.) reveliereanus (Courtiller, 1860), S. (J.) combesi (Sornay, 1951), S. (Ingridella) malladae (Fallot, 1931), S. (I.) depressus (Wiedmann, 1960), S. (Spathites) laevis (Karrenberg, 1935), S. (S.) sulcatus (Wiedmann, 1960), Mammites nodosoides (Schlüter, 1871), Kamerunoceras ganuzai (Wiedmann, 1960) and K. turoniense (D'Orbigny, 1850) have been also presented. In addition, the specimen of Ammonites inconstans Schlüter, 1871, of Mallada (1891, 1892), the holotype of Mammites (Pseudaspidoceras) armatus Pervingquière (1907), and the syntype of its variety fraichichensis Pervinquière (1907) have been refigured. Studies on the morphologies and the geographical and stratigraphical distributions of all of these species have led to the identification of several phylogenetic relationships between them, and to distinguishing five main phases in the evolution of the family, characterized by the successive dominance of Spathites (Jeanrogericeras) 1, of Spathites (Ingridella), of Spathites (Jeanrogericeras) 2, of Mammites and of Spathites and Mammites. © 2007 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart.
The ammonites assigned to the genus Vascoceras of the Wiedmann (Universität Tubingen, Germany) and Goy, Carretero and Meléndez (Universidad Complutense de Madrid, Spain) collections obtained from the upper Cenomanian and lower Turonian of the Iberian Trough have been revised. Subsequently, new representatives of the species Vascoceras gamai, V. charoni sp. nov., V. barcoicense, V. durandi, V. cauvini, V. amieirense, V. harttii and V. kossmati have been studied and presented. Finally, studies of the morphologies and the geographical and stratigraphical distributions of these ammonites have led to the identification of several phylogenetic relationships between them, and to distinguishing two main phases in the evolution of the family Vascoceratidae, characterised by the successive dominance of the "primitive" Vascoceras and of the "evolved" Vascoceras.
The prosperous epoch in the history of palaeontology which can in Germany be outlined by the works of OTTO HEINRICH SCHINDEWOLF and HEINRICH KARL ERBEN is shown in retrospective.
Comparisons of diagnostic morphological characters of M. ftaasi with other derived Schizotheriinae.
Karst fissure fillings of Petersbuch (MN 6), Franconian Alb, Southern Germany, yielded a large number of new finds of the schizotheriine chalicothere Metaschizotherium fraasi, which until then had only been known by its cheek teeth, co-ossified phalanges, and astragalus and calcaneum. Thus, for the first time the lower jaw, the almost complete manus and pes, the tibia, and parts of other long bones are described. New information on the dentition is gained and the presence of well-developed lower incisors is noted. A comprehensive morphological comparison to other schizotheriine chalicotheres is carried out. The species status of M. fraasi within the genus Metaschizotherium is confirmed. M. fraasi is found to be closely related to but not directly decended from the slightly older M. bavaricum (southern German MN 5-6).The morphological resemblance of Metaschizotherium to North American Moropus is striking and reveals a closer relationship than previously assumed. The referral of Metaschizotherium to the Eurasian and African genus Ancylotherium is rejected. Several formerly insecurely referred schizotheriine remains from Europe are now more securely assigned to either Metaschizotherium or Ancylotherium. The first immigration of Ancylotherium into Europe is estimated to have happened around MN 7-8. It is not yet clear whether M.fraasi (recorded from the karstic plateau of the Franconian and Swabian Albs) and M. bavaricum (known from more humid environments of the Upper Freshwater Molasse) overlapped ecologically or temporally during MN 6. A diet composed of browse and fruit (possibly Celtis) or bark is assumed for M.fraasi, and probably the clawed fore feet rather than anterior teeth were used to obtain these food items.
The validitiy and the assigment of the genus Willungia Powell, 1938, to the higher systematics is clarified. The genus is based on Willungia tasmanica Powell, 1938, from the early Miocene of Tasmania. Cypraea ovulatella Tate, 1890, from the late Eozän of South Australia is also assigned to the genus. The assignment of Marginella fracta Tomlin, 1916, is doubtful because the species is based on a damaged and deformed holotype. Also the assignment of Willungia maoria Powell, 1938, from the Miocene of New Zealand cannot be confirmed because the shell morphology differs essentially from the type spezies. © 2013 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.
Many complete skeletons of Geiseltaliellus longicaudus KUHN are described from the Middle Eocene of the fossillagerstätten Geiseltal near Halle an der Saale and Grube Messel near Darmstadt, Germany. The investigation supports the close similarity to the Corytophanidae with its subfamily Basiliscinae. But for practical reasons it was necessary to erect the subfamily Messelosaurinae nov. based upon the following characters: position of the Foramen parietale in the frontoparietal suture; lacking of an occipitally enlarged parietal crest; coronoid with a large processus labialis. The Messelosaurinae includes: Geiseltaliellus longicaudus KUHN, 1944 from the Lower and Middle Eocene of France, Belgium and Germany, Cadurciguana hoffstetteri AUGÉ, 1987 from the Upper Eocene of France, Aciprion formosum COPE, 1873 from the Lower - Middle Oligocene of the USA, Cypressaurus hypsodontus HOLMAN, 1972 and Holmanisaurus oligocenicus (HOLMAN, 1972) both from the Lower Oligocene of Canada. Capitolacerta dubia KUHN, 1944 and Geiseltaliellus louisi (AUGE, 1990a) are junior synonyms of G. longicaudus. Possibly the fracture of the right humerus in HLMD-Me 10207 indicates its directly or indirectly cause of death. Soft part structures are preserved in form of a skin impression in SMF-Me 2a+b and in the occurrence of epidermal scute remains in most of the specimens of Geiseltaliellus from the Geiseltal and the Grube Messel.
Cratovitisma odlreadi Bechly, 2007 – a beetle-like cockroach, known from single Lower Cretaceous sediment specimen from Crato in Brazil, was designated by monotypy. C. cortexi Sendi, sp.n. (Lebanon) and C. bechlyi Podstrelená, sp.n. (Myanmar) from Early and Late Cretaceous amber respectively reflect a specific bark niche with unique disruptive camouflage coloration and minimum morphological differences over the significant temporal (130–120–98 Ma) and spatial (Laurasia – Gondwana) gaps. The earliest derivation within the family is documented with significantly symplesiomorphic (with Jantaropterix Vršanský, 2003) fully carinated legs. © 2018, E. Schweizerbart'sche Verlagsbuchhandlung. All rights reserved.
About 180 bone, teeth and antler remains representing six different large herbivorous mammals have been recovered from Weichselian glacial or glaciofluvial deposits in South Scandinavia. Mammuthus primigenius is represented in the largest number and they are supplemented by a few, but nevertheless important, specimens of Rangifer tarandus, Bison priscus, Megaloceros giganteus, Ovibos moschatus, and Equus ferus. Radiocarbon dates performed on remains of all six species place the assemblage within a long lasting late Middle Weichselian period with prevailing interstadial conditions (c. 45-20 14C kyr BP). Together with palaeogeographical and palaeobotanical reconstructions this documents an expansion of the European Mammoth Steppe into southern Scandinavia during the late Middle Weichselian. The interrelationship between glacial history and the faunal changes observed during the period supports the idea that the displacement of a species' distribution is best explained as a combination of expansions and local extinctions of marginal populations. Furthermore, it seems that the rate of expansion of herbivorous mammal populations into newly deglaciated areas was controlled by the rate of 'habitat migration' - the time lag in vegetational response to the climatic improvement.
Erycites sutneri Gemmellaro, 1886, JPi.24.4, Aalensis Zone, Arroyo Milanos section. Figs. 2–8: Erycites fallifax Arkell, 1957. 2: CM2.19.1, Opalinum Zone, Comptum Subzone, Cerro Méndez (section CM2), specimen figured in Linares et al. 1988, pl. 1, fig. 8. 3A, B: CM3.12.1 (inner whorls, lateral and ventral views), Opalinum Zone, Comptum Subzone, Cerro Méndez (section CM3). 4: CM.(74–76).1, Opalinum Zone, Comptum Subzone, Cerro Méndez (section CM). 5: CM2.25.1 (flattened specimen), Opalinum Zone, Comptum Subzone, Cerro Méndez (section CM2). 6: CM2.24.5, Opalinum Zone, Comptum Subzone, Cerro Méndez (section CM2). 7: CM5.4.10, Opalinum Zone, Comptum Subzone, Cerro Méndez (section CM5). 8: CM2.19.2, Opalinum Zone, Comptum Subzone, Cerro Méndez (section CM2), specimen figured in Sandoval et al. 2011, text- fig. 10, 3. All figures are of natural size. 
Dimensions of the more significant specimens of Erycites barodiscus Gemmellaro, 1886.
Dimensions of Erycites sutneri Gemmellaro, 1886.
Dimensions of the more significant specimens of Erycites fallifax Arkell, 1957.
Dimensions of Erycites intermedius Hantken in Prinz, 1904.
Hammatoceratoids (Ammonitida) are common (frequent) in the Upper Toarcian lowermost Bajocian of different sections of the Subbetic domain (Betic Cordillera, southern Spain). The Betic Cordillera belongs to the Mediterranean province of the westernmost Tethys. In several sections of this Mediterranean area, mainly those consisting of marly-limestone rhythmites and where ammonoids are abundant, the stratigraphic range of the diverse taxa present they can be easily and accurately determined. This also shows the morphological changes and the evolutionary processes that took place in the ammonite taxa that appear in the stratigraphic record. A great number of specimens from Subbetic domain, belonging to the family Erycitidae (Hammatoceratoidea) and collected in sections which were minutely sampled bed by bed, are studied in detail. The analyses of the Subbetic material together with the bibliographic review of other Western Tethyan erycitids has yielded significant results. Taxonomical analyses allow the family Erycitidae to be subdivided into three subfamilies: the Mediterranean subfamilies Erycitinae Spath and Zurcheriinae Hyatt (this latter previously studied) and East Pacific Podagrosiceratinae Westermann & Riccardi. The genera Erycites Gemmellaro, Abbasites Buckman, Abbasitoides Geczy and Cagliceras Rulleau & Elmi are included in Erycitinae. Ambersites Buckman is considered synonymous of Abbasites and, Praerycites Venturi is a Phymatoceratidae rather than an Erycitidae. A detailed review to the species level shows that a considerable number of the Mediterranean species described, mainly from Hungary, may be synonymous. In the Subberic domain, erycitins extend from Upper Toarcian (Speciosum Zone) to uppermost Aalenian (Concavum Zone, Limitatum Subzone). Phylogenetic analyses indicate that Cagliceras picenum is possibly the earliest Erycitidae and originated from some species of the genus Geczyceras or Crestaites in the Speciosum Zone.
The investigation of the Late Paleocene to Early Eocene ostracode faunas extracted form El Quss Abu Said Plateau (Farafra Oasis) in the Western Desert of Egypt yielded 85 species and subspecies which belong to 53 genera. From these species and subspecies, 28 are new. The stratigraphic range of all species is given. The biostratigraphic, paleoecologic and paleobiogeographic implications are discussed. The close similarity of the Late Paleocene to Early Eocene ostracode faunas of west Africa and southern areas of the Tethys is emphasized.
Using for the first time detailed analysis of the biozonal ranges of 75 acanthodian species, the zonal stratigraphical scheme for the Lower and Middle Devonian in the East Baltic Area and Byelorussia has been worked out. Description of zones with indicated stratotypes, key sections and zonal species associations indicate peculiarities of combinations between characteristic and transitional species, and stages of phylogenetical development of acanthodians. The Lower Devonian in the regions studied is characterized by the development of the representatives of Climatiidae and Ischnacanthidae, whereas the Middle Devonian mainly contains Diplacanthidae and Cheiracanthidae. All the known acanthodians from the Lower Devonian (based on scales) in the East Baltic Area and Byelorussia, including two new genera (Endemolepis and Lietuvacanthus) and eight new species (Cheiracanthoides planus, C. nativus, Tareyacanthus dissectus, Endemolepis inconstans, Gomphonchus tauragensis, Poracanthodes subporosus, Lietuvacanthus fossulatus and Ectopacanthus? pusillus) are described. Specific histological structures of Poracanthodes, Lietuvacanthus and Ectopacanthus? scales are shown. The presence of complicated systems of pore and vascular canals allowed to distinguish a new histological "Poracanthodes"-type.
This is the third part of a tripartite survey on Devonian trilobites of the Rhenohercynian. Paleontology Region of the Oberbergische Land/Sauerland (shelf): 18 taxa (as mentioned above) are introduced as new ones. Till now, Kayserops has not been recorded later than in Emsian. In the northwestern Rhenish Mts last steps of development in this group can be identified in upper Eifelian. In early Givetian this species group is "replaced" by the similar Rheicops grevensteinensis g. & sp.n. which is characterized by some features reminding of "Comura". Almost synchronously and in a comparable mode development in late "Comura" species takes place, resulting in organisms called Gudralisium g.n., which are hardly to distinguish from Rheicops. Postlarval ontogenesis in two "populations" of Eifliarges is characterized by individualisation of segments in the pleural fields of the PYG. These two "populations" are similar to each other in the mode of this development, but they differ in its result, i.e. in the maximum number of individualized ribs and spines. Charybdaspis comes g. & sp.n., type species of this genus is morphologically closely related to Radiaspis radiata, type species of Radiaspis. But they clearly differ from each other in features of the THO: In comes the paired lateral spines of pleura 1-7 might have a common base in the convexe median pleural band, respectively. In radiata the anterior spine originates in the anterior pleural band, whereas the posterior spine comes from the median band. Both taxa have a similar and unique arrangement of the spines of pleura 8 and 9, which differs strongly from pleura 1-7. Kellerwald area ("trough"): Well preserved taxa (as mentioned above) are present. - Generally, Givetian odontopleurines are rare. Such a taxon is genus (?novum) ex Koneprusiinae sp.n. W, characterized by 3 + 1 individualized rings in the pygidial rhachis. Harz Mts (shelf): Upper Emsian taxa of Phacops, Acastellina, Treveropyge, Comura, and Malladaia are discussed. - The pygidial border of tiny holaspids in a "population" of Acastellina errabunda sp.n. is incised. In the course of the postlarval ontogenesis an almost entire margin occurs. - Malladaia festenburgensis sp.n. is the first finding of this genus in Germany. Lahn-Dill region ("trough"): Upper Emsian trilobites (as mentioned above) may resemble taxa of the same age or slightly younger from the Eifel hills and the eastern Sauerland. - A species of the "blind" phacopine Illaenula is reconstructed. Eifel area (shelf): Taxa from Wiltz, Heisdorf, Lauch, and Freilingen strata (late Upper Emsian, early Eifelian, and early Givetian) are discussed briefly to enlight similarities and differences with the situation east of the river Rhine. Stratigraphy Oberbergisches Land/Sauerland: In the eastern Sauerland the position of the p-b (partitus boundary) seems to be lower situated than assumed. - Of stratigraphic importance in the western Sauerland should be the chronology of some Asteropyginae close to the otomari Event. Here a lithologic change takes place, accompanied by the onset of the new Rheicops and Gudralisium, which are frequent and easy to identify. Harz Mts/STP: A clear change in trilobite faunas reminds strongly of such taking place close to the p-b in its stratotype (Eifel area), but also of one happening in late Upper Emsian of the eastern Sauerland and the Dill region. Occurrence of Paralejurus intumescens in the Calceola shales and lack of typic Eifelian taxa might vote for an Emsian age of these shales, which formerly were regarded as early Eifelian. Faunal structure and geographic distribution Region of the Oberbergisches Land/Sauerland: Between Upper Emsian and Givetian different faunas are living on the shelf, each of them clearly differentiated., e.g. in hemipelagic and neritic ones. The frontier approx. between the western and the eastern Sauerland stands for such a break. Its pattern seems to be very constant for long periods of time. Widely distributed taxa occur especially in early Eifelian of the eastern Sauerland. - Upper Emsian trilobites are rare in the north-western Sauerland, but they are numerous in the eastern Sauerland and in the Rothaargebirge. Here close to the p-b the number of taxa decreases slightly to clearly. In the early Eifelian of the Rothaargebirge (transition shelf/"trough") trilobites are largely lacking, but in the eastern Sauerland and for the first time since Lochkovian in the western they are common. The north-western frontier of their distribution is now shifted clearly to north-west to the north-western Sauerland. Here is remains during Eifelian. In early Givetian this frontier is moving a little bit to the north-west. Synchronously, in the eastern Sauerland the number of taxa is strongly decreasing. Faunas of Upper Emsian age of the east Sauerland consist mainly of Phacopida, sometimes accompanied by Paralejurus, cornuproetids, lichids. Similar structures are known from the Lahn-Dill region and the Eifel area. Close to the p-b Cyphaspides and chotecopids occur, reminding of synchronous taxa of the Lahn region; initially, the geographic distribution of this new fauna in the Sauerland is restricted. Parallel existing Asteropyginae faunas seem to originate in Upper Emsian and they are replaced by e.g. Thysanopeltis, cornuproetids, and now more widespread Cyphaspides and chotecopids not before early Eifelian. The start of the early Eifelian in the western Sauerland/Bergisches Land seems to be characterized by few late Upper Emsian taxa coming from e.g. the Lahn-Dill region. In contrast to this the relations to the Eifel area are much clearer - as it can be stated for the whole Eifelian. In the elder Eifelian, fauna and lithofacies of shelf deposits (neritic to hemipelagic facies) in the eastern Sauerland contrast sharply with those of the west (neritic facies): in the Oberbergisches Land up to the east border of the western Sauerland, neritic fauna (scutelluids, proetids, large-eyed Phacopinae, Asteropyginae) with clear affinities to faunules of the Ardenno-Eifelian region (western Rhenohercynian) is dominating. Such neritic taxa are unknown in synchronously developed nearby "pelagic" deposits (Lahn-Dill, Kellerwald) (but possible forerunners occur here in assumed late Upper Emsian). In contrast to this, the faunules of the eastern Sauerland can clearly be influenced seemingly by pelagic faunas, reminding of synchronous taxa of the Kellerwald or of the Lahn-Dill region. Typical are thysanopeltids, certain cornuproetids, cyphaspidids, and chotecopoid phacopines, which seem to be absent or which are extremely rare west of the eastern Sauerland. But in some parts of the eastern Sauerland, neritic taxa of Upper Emsian age and western or southern provenience exist for a short period of time parallel to the mentioned pelagic organisms. In the course of the Eifelian in the western Sauerland remarquable changes in faunal structure take place frequently; they are mainly characterized by entrance of new taxa, e.g. dechenellids, but "never" by taxa coming from the eastern Sauerland. A clear alternation can be stated "shortly" after the otomari Event: now a reduced fauna lives in the west, mainly consisting of Proetidae, Phacopidae, Asteropyginae. There is no hint about clear influences from other regions. In the eastern Sauerland the "lack" of trilobites in post-event sediments indicates a much more drastic change. Trilobites of middle Givetian limestones from the transition shelf/"trough" of the eastern Sauerland remind weakly of species known from probably synchronously developed pelagic submarine rises of the Kellerwald region. Species related to those of back-reef deposits (Massenkalk, middle Givetian) have been identified in the Lahn-Dill region. A general lack of data about Givetian trilobites makes it difficult to judge about worldwide relations of faunas, but it looks like that there are close faunistic connections between English limestones and Rhenish Massenkalk. Kellerwald area: Re known species of late Emsian and early to middle Eifelian there should be close relations to taxa of the Lahn-Dill region. The Odershausen fm (± Eifelian/Givetian boundary) of Wildungen has yielded five species; one might occur in deposits of the western Sauerland, too. From Givetian cephalopod limestones of the Diemelsee area (Martenberg), from reef complexes of the Harz Mts, and from limestones of the Lahn-Dill region some organisms are known comparable with taxa of the Cheirurus limestone. These middle Givetian faunas of Wildungen remind of pelagic taxa of Eifelian age from the same area. In early Upper Devonian some organisms appear, which can be identified in Harz Mts and in the Lahn-Dill region, too. With this fauna of Wildungen, the lack of knowledge in the geographic distribution of certain trilobite associations of the pelagic facies is reduced. Harz Mts/STP: Two different faunas can be distinguished in late Upper Emsian: preferably neritic taxa in the speciosus beds, mainly seemingly pelagic ones in the overlaying Calceola shales. On generic level there are clear parallels to trilobites occuring in the Rhenish Mts, but most of the species differ evidently from the Rhenish ones. Moreover, comparable findings are made in some neritic influenced synchronously deposited sediments of Poland.
A high-resolution event-stratigraphy for the Mid-Paleocene to Early Eocene of the southern North Sea Basin is proposed, based on new lithostratigraphic, biostratigraphic and magnetostratigraphic information. The revision of the lithostratigraphy of the Lower Palaeogene of Belgium has led to the recognition of four major depositional sequences, separated by unconformities (ascending): 1. a lower exclusively carbonate sequence of Danian age (not studied in detail here), 2. a mixed siliciclastic-carbonate sedimentation of Selandian (= Heersian) age, including the Hainin Formation (SW, continental), its lateral equivalent the Opglabbeek Formation (NE, continental) and the Heers Formation (NE, marine), 3. an exclusively siliciclastic sedimentation of Thanetian (= Landenian) age, corresponding to the Landen Group (new status, formerly Formation), and 4. an upper predominantly clayey sequence, corresponding to the leper Group (new status, formerly Formation). The Landen Group and the leper Group are subdivided into Formations (Fm) and Members (Mb), which are mostly formally described for the first time. Five units are new: the Maaseik Clay Mb (formerly "calcareous Landen Clay"), the Saint-Ghislain Fm (regrouping of several members) and the Oosthoek Sand Mb (formerly included in the Knokke Mb) within the Landen Group, the Zoute Silt Mb (formerly Member X of KING) and the Egemkapel Clay Mb (formerly included in the Kortemark Silt Mb) within the leper Group. The major calcareous nannoplankton, dinoflagellate and planktonic foraminiferid events are discussed. These events, about 50 in total, are synchronous throughout the North Sea Basin, allowing a high-resolution biostratigraphy (average resolution of 50 k.y. for the Ypresian). Their calibration with the standard Palaeogene calcareous nannoplankton (NP) zonation and the geomagnetic polarity timescale has enabled estimation of the duration of sedimentation and calculation of sedimentation rates. Regional correlations with Denmark, the Paris Basin and southern England are proposed. The stratigraphic information, including geophysical well log data, is interpreted in terms of sequence stratigraphy. A single third order sequence is recognised in the Selandian (sequence S-A, probably corresponding to cycle TA 1.4 of HAQ and cycle TP 1.4 of BAUM). It has a rather restricted distribution (Denmark, NE Belgium) and is of late NP 4-NP 5 age. Three sequences are identified within the Thanetian: a lowermost sequence T-A, covering the interval from the upper part of Zone NP 6 to the upper part of Zone NP 8 and occurring throughout NW Europe (TP 2.1 of BAUM), a middle sequence T-B, of early NP 9 age, restricted to N France and the Paris Basin (TP 2.2 of BAUM), and an upper sequence T-C, deposited in mid-NP 9 times, widely distributed in the Paris Basin and recorded from Belgium (TP 2.3 of BAUM). At least 7 third order sequences are identified within the classical Ypresian. Sequence Y-B was deposited during late NP 10 and early NP 11 times and probably entirely within chron C24BR. The base of sequence Y-C coincides with the first consistent occurrence of calcareous nannofossils and with the base of the Roubaix Clay Mb, and corresponds to the start of chron C24BN. The first occurrence (FO) of Discoaster lodoensis, defining the NP 11/NP 12 boundary, lies within the upper part of sequence Y-D. It coincides with the end of chron C24AN. Sequence Y-E includes the upper part of the Roubaix Clay Mb, the Aalbeke Clay Mb and the Kortemark Silt Mb and falls entirely within NP 12. Its base is marked by the FO of Micrantholithus mirabilis, its maximum flooding surface, which is very close to the start of chron C23N, by a major planktonic foraminiferid influx. Sequence Y-F, which presents a reversed geomagnetic polarity, corresponds to the Egemkapel Clay Mb. The overlying Egem Sand Mb represents the lowstand systems tract of the next sequence Y-G. Its base is marked by the entry of common Rhabdosphaera crebra and corresponds to the start of sub-chron C23N2. The NP 12/NP 13 boundary, which seems to coincide with the end of chron C23N, falls within the upper part of the Hyon Sand Fm. The Early Palaeogene stages and their boundaries are re-evaluated. The age of the Hainin and the Dormaal Vertebrate faunas is discussed. The nature of the Paleocene/Eocene boundary is specified. Traditionally this boundary has been situated at the base of the Mont-Héribu Clay Mb (base of sequence Y-B), which corresponds to the FO of Cerodinium wardenense and falls within NP 10. From a classical point of view, and according to the newest information, it should be placed at the base of the underlying Zoute Silt Mb (at the transgressive surface of sequence Y-A), and consequently at the base of NP 10 and the base of the Deflandrea oebisfeldensis acme. In the interest of wider global recognition one might be tempted to place this boundary at the sequence boundary of T-C and Y-A, which underlies the "upper Landenian" fluvio-lagoonal deposits of Belgium and the Sparnacian facies in France. In this context it should lie within the upper part of NP 9, at the base of the Apectodinium spp. acme. The nannofossil family Heliolithaceae is revised. A new Heliolithus species (H. knoxii) is introduced.
Neogene deposits in the Northern-Aegean area (Axios-depression: Katerini, Thessaloniki/Trilophos, Strimon-depression: Choumnikon) were studied by taking stratigraphic sections, making extensive collections of fossils and, in the area of Thessaloniki, by geological mapping. The fresh and brackish water gastropods from the fossiliferous sediments (Trilophos-formation) are revised. Against the existing typological classification, some cases of new taxonomic correlations can be shown. The number of the existing species is restricted. Two new species arc described. An endemic development with an evolutionary change of the shell morphology of the neogene gastropods was not known for the Northern-Aegean area untill now. It can be demonstrated by remains of fishes and molluscivouros brachyuran crabs, which left breakage induced fractures on the gastropod shells, that there was an intensive predator-prey relationship. The morphological changes of the gastropod shells (thickening of the outer lip, modifications of sculpture, development of a special operculum-closing-mechanism) are interpreted as adaptiv defences against these predators. The intensity and maturity of the predator-prey relationship and the tempo of the morphological change of the gastropod shells is shown. The importance of predator-prey interactions for the evolution of gastropod shell sculpture is discussed. The evolution of the gastropods gives important evidences for the palaeogeographic development of the neogene depressions. On the basis of these examinations and by the evaluation of the changes in the gastropod successions an ecostratigraphy for the Trilophos-formation is erected. Thus a stratigraphic correlation of the sediments in the Northern-Aegean area is possible. Furthermore neogene, fossiliferous marine to brackish deposits from the Strimon-depression, the isle of Skiros and Trakhones (near Athens) were examined. The fossiliferous, brackish-limnic sediments of the Northern-Aegean area are of pontian age, correlating with the highest Tortonian and Messinian in the Mediterranean. The marin-brackish deposits are of maeotian age, correlating with the middle to higher Tortonian. The palaeogeographic evolution of the Northern-Aegean area during the Tortonian and Messinian is described.
This study deals with Eocene lipotyphlans, especially the erinaceomorph amphilemurids. The species known to date belong to six, variably diversified genera: Macrocranion, Gesneropithex, Amphilemur, Alsaticopithecus, Pholidocercus, and Echinolestes nob., all European except Macrocranion which is also North-American. The studied material mostly consists in original tooth specimens, obtained from 18 French localities, the age of which spanning the early, middle and late Eocene. The sedimentological and environmental characters of these localities extend from lacustrine or fluviatile sediments within continental open basins to paleokarstic fillings within older carbonateous platforms. The analyse, then morphologic and morphometric comparisons, allowed us to display the specimens according to the classic data. All the known genera except Pholidocercus are represented within the studied material. Several known species are recorded, or else their systematic position is revised, or precised for some ones previously quoted as sp. New taxa, six species and the Echinolestes genus (MAITRE et al. 2006a), plus one species (this paper), are described, figured and compared in further extent. The specific diversity appears to be marked within some genera, e. g. Macrocranion (early to late Eocene) and Gesneropithex (middle to late Eocene). This allows us to propose phylogenetic hypotheses among them. Complementary material from field or previous collections, e.g. for Gesneropithex grisollensis from Grisolles, G. aumelasensis n. sp. from Aumelas, Echinolestes neboulensis from Aubrelong 2 and Montells, extends these hypotheses to alternative views. The Macrocranion, Gesneropithex, and Echinolestes species well exemplify some evolutionary trends of the amphilemurid family: inferred from the size and morphology, the body mass and the bunodonty increase along with time within the genera, and the tooth pattern is evolving simpler among Gesneropithex and Echinolestes. Some late Eocene species, still poorly documented, are left in open ordinal status. They have the peculiar interest to illustrate a potential evolutionary link between the classic amphilemurid tooth morphology and that, more generalized, of older eutherians classified among the Leptictida.
Sixty-two brachiopod species belonging to 42 genera are systematically described for the first time from the Viséan-Serpukhovian Heshilafu Formation of the western Kunlun Mountains, North-west China. Two new genera Robertsella and Aitegounetes are proposed. New species include Rhipidomella aitegouensis, Rhipidomella radiata, Brochocarina kunlunensis, Rugosochonetes damusiensis, Robertsella tarimensis, Robertsella greenhillsensis, Aitegounetes aitegouensis, Aitegounetes burvillensis, Marginatia ruani, Latiproductus convexa, Globosoproductus xinjiangensis, Semiplanella yangi, Unispirifer heshilafuensis, and Beecheria yeerqiangensis. Six brachiopod assemblages are recognised from the Kunlun faunas. Close correlation of the Kunlun Mountains faunas with those from South China, Tienshan Mountains, Qilianshan Mountains and Tibet of China, Japan, Malaysia, Australia, central Asia, Urals, Kutznesk Basin and Moscow Basin of Russia, West Europe, and North America reinforced by some data from the associated foraminifers, fusulinids, conodonts and corals, suggests that the first three assemblages, Brochocarina kunlunensis-Orthotetes australis, Rugosochonetes hardrensis-Marginatia ruani and Buxtonia pseudoscabricula-Punctospirifer scabricostus are probably early Viséan in age, the Pugilis pugilis-Globosoproductus xinjiangensis Assemblage is of a middle Viséan age, the Semiplanella yangi-Datangia weiningensis Assemblage is late Viséan, and the Gigantoproductus edelburgensis- Striatifera striata Assemblage is Serpukhovian. Faunal correlation with the regions outside the Kunlun Mountains also reveals that the faunal affinities of the Kunlun assemblages with those of adjacent regions were variable throughout the Early Carboniferous. Generally, in sharp contrast to the extremely high generic and specific affinities between Kunlun and South China faunas in the Tournaisian, faunal links with South China apparently weakened in early Viséan. The Kunlun fauna appears to be of a mixed nature, with elements from Europe, North America, Siberia and Gondwanaland, indicating a possible intermediate position between European, American, Gondwanan as well as South Chinese faunal provinces. The middle-late Viséan faunas of Kunlun Mountains remained strongly an European aspect with limited South Chinese species, and completely lack any North American or Australian forms. Instead, the Kunlun Mountains, along with other central Asian blocks, such as the Chaidam Basin, northern Tienshan-Junggar, Uzbekistan and Kazakhstan, developed a higher degree of endemism, suggesting that the Kunlun Mountains were probably biogeographically and palaeogeographically further away from South China and closer to the central Asian blocks. The European and central Asian affinities of the Kunlun faunas became reinforced in the Serpukhovian. At the same time, the Kunlun Mountains maintained strong faunal affinities with these northwestern Chinese blocks (Qaidam and Tienshan-Junggar), and the links with South China further decreased.
The extensive vertebrate excavations of the Late Jurassic to Early Cretaceous around the Tendaguru hill in Tanzania in the early 20th century also yielded significant invertebrate faunas. The corals were first described by Dietrich (1926) and his work conformed to a remarkably high standard for his time. Since then, progress in examination methods and other criteria of coral classification has made a modern revision necessary. In addition, the stratigraphy of the coral bearing sediments has greatly improved over the past ten years, allowing a better palaeobiogeographic analysis. The present paper gives an introduction to the research history, discusses the various denominations of the lithostratigraphical units exposed in the Tendaguru area, and explains the progress of the stratigraphy of these units. Using both the original material described by Dietrich, as well as collection material that he did not describe, the corals of the Cretaceous are described and illustrated using new thin sections. Several corals from the Early Cretaceous of Kenya are also included. The Jurassic corals from the Tendaguru area have not been examined. In total, 15 species from the Late Valanginian to Early Aptian unit and 31 species from the Late Aptian are described. Two genera described by Dietrich that were largely forgotten and many species established by him that were not precisely interpreted in later literature are revised here. Camptodocis replaces Actinaraeopsis Roniewicz, 1968, and Metaulastrea corresponds to the concept of Amphiaulastrea Geyer, 1955, which is considered a junior synonym of Pleurostylina and should no longer be used. Together, these revisions place the Cretaceous corals of the Tendaguru area in a modern taxonomic and palaeobiogeographic context.
In 2004 by Rook and co-authors have been described the cervical vertebrae of a large primate from the Early Pleistocene record of Pirro Nord (Apulia, Italy). These specimens have been attributed to a large cercopithecoid on the basis of the overall morphology. According the European biochronological framework the authors proposed attribution of these fossils to the genus Theropithecus.The Rook et al. (2004) paper has been recently criticized by Patel et al. (2007) who questioned the relevance of the fossil primate cervical vertebrae for taxonomic identification. We offer here our view on the morphological evidence and we discuss the Early Pleistocene scenario of mammal faunals dispersal from Africa into Eurasia.© 2013 E. Schweizerbartsche Verlagsbuchhandlung, Stuttgart, Germany.
From the epineritic (Asturoleonesian) Aguión Formation (Upper Emsian, Lower Devonian) of north Spain (Prendes, Provincia de Asturias), a diverse ostracod fauna is described. Of the (in 43 genera and subgenera) identified some 61 species, 12 are already known and 4 are new, namely Welleriella afabushikae n. sp., Obotritia carallela n. sp., Birdsallella aguionis n. sp. and Hanaites (Praehanaites) praehanaites n. sp. (type species of the new subgenus H. (Praehanaites) n.g., Hollinidae); the rest (including Bairdia (Rectobairdia) sp. A forma arnao n. f., B. (Cryptobairdia) sp. A forma aguion n. f., Bairdiacypris sp. A forma casamieres n.f., Coeloenellina sp. A forma aviados n.f. und Rishona sp. A forma argovejo n.f.) are left in open nomenclature. With respect to the ecotype classification of Palaeozoic ostracods proposed by BECKER 1975 [correctly quoted as BECKER in BANDEL & BECKER 1975; emend. BECKER 1981c, BECKER & BLESS 1990], the Aguion assemblage (= "mixed fauna" including Acratia, Acanthoscapha, Kirkbyellina and Rishona) is indicative of an (as demonstrated by numerous Bairdia species), open-marine offshore environment below the wave base. Close relationships are shown to the peribiohermal ostracod faunas of the Asturian Moniello Formation (uppermost Emsian) as well as to offreff-assemblages of the Leonesian realm, especially to the Upper Emsian Santa Lucía Formation and, consequently, to (cum grano salis) contemporary deposits of the north African Sahara and the Thüringische Schiefergebirge. Seemingly, ostracod faunas described from the Palentine facies realm are rather unrelated.
The discovery of fossil fish and reptiles in the banks of the Conecuh River at the Point «A» Dam site, northwest of the town of Andalusia, Covington County, Alabama, has brought to light 38 selachian species belonging to 31 genera, from the Lisbon Formation (Middle Eocene, Lutetian). One new genus and three new species are described: Orectolobus ziegenhinei nov. sp., Tethylamna dunni nov. gen. nov. sp. and Scoliodon conecuhensis nov. sp. This study allows us to up-date the previous studies published on the selachians from this locality and to increase the faunal list. The oldest occurrence of the genera Orectolobus, Sphyrna and Scoliodon is noted. The genus Tethylamna nov. seems to appear during the Lutetian, before spreading all along the southern margin of the Tethys ocean during the Bartonian and the Priabonian.ThePristidae are particularly diversified, indicating coastal, shallow water conditions during deposition of the fossiliferous bed. The Lutetian fauna of Andalusia, Alabama shows more paleobiogeographic affinities with those of the southern Tethyan margin than with those of northwestern Europe. © 2016 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.
Until recently Upper Silurian graptolites were rarely known from the South Tien Shan area of Central Asia (former USSR). Detailed mapping and biostratigraphic studies have revealed a complete succession of late Ludlow and Pridoli graptolite-bearing mudstones and siltstones from the Kursala Fm., a stratigraphical unit which is preserved as a part of an extensive nappe structure in the northern foothills of the Alai Range, Kirgizia. A high resolution graptolite zonation, comparable with that of the Upper Silurian of the Prague Basin is established in the study region. Graptolite biostratigraphic data obtained from the upper Ludlow (Ludfordian) beds of the Kursala Fm. provide additional information about the graptolite assemblages which precede the appearance of the early Pridoli monograptids. The global correlative potential of the internationally recognized Pridoli graptolite biozones (the parultimus, ultimus, branikensis and some levels within the transgrediens s.l. Biozone) is elaborated. Sixteen monograptid species (two new: M. petri and M. tumultuosus) are described.
In the present paper the lithostratigraphic classification from Ashgillian to Upper Triassic (only for some of the geological zones of Albania, proved by the study of conodonts) is presented for the first time. Lithostratigraphic divisions are classified referring to Formation or Subformation levels. This classification is realized for the Palaeozoic deposits of the Korabi zone and less for the Gashi zone. The classification of Triassic deposits, parallel with the Korabi and Gashi zones, are also done for the Mirdita and Krasta-Cukali zones. This classification (based on conodonts) is mainly related to the facies of continental slope or pelagic environment. The Kollovozi is the most northeastern subzone of the Korabi zone, where the oldest formation is the Sandstone-quartzite Formation of Kollovozi. The next formation above is the Shale Formation of Nelaj which is divided in subformations. Further up two other formations are present in ascendig order: The Volcanic Formation of Shtrezi and Sandstone Formation of Shtrezi. For all of these four formations an Ordovician age is accepted.Thefourth stratigraphic section of this formation is the Prroi i Mullirit outcrop. It is the continuation of the Sandstone Formationof Shtrezi, whose limestones contain Cornuodus sp., Hemarodus sP. cf . europaeus etc. (Ashgillian). The Sorokoli brachysynclinal belongs also to this subzone, where in its carbonatic facies Kockelella variabilis to Ozarkodina confluens and Ancyrodelloides cf. delta (from Ludlow to Lower Devonian) are found. In the area of the Kollovozi subzone the tectonic window of Borja is also mapped, which belongs to the Muhur-Çaja western subzone. In the carbonatic strata of this tectonic window plenty of Frasnian conodonts have been found (Palmatolepis jamiae, P. ederi, P. rhenana nasuta etc). In the subzone of Malsia e Korabit the Shpati Perendimor (Western Slope) is distinguished which is represented by shales and carbonates and the Carbonate Formation as well. The Black shale Formation (Western Slope) ranges in age from Late Silurian - Early Devonian (?) to Emsian (P. serotinus). The Carbonate Formation ranges from Emsian to Frasnian in age, where different conodonts have been determined (? P. rhenana nasuta, P. hassi-ederi etc.). The Limestone of the Korabi Formation is characterized by the imbrications, tectonic style (overthrusting tectonic), and its age ranges from Early Devonian (Polygnathus serotinus) to Middle Devonian (Polygnathus costatus oblongus, Tortuodus kockelianus australis, Klapperina disparilis etc.). Among the profiles of this subzone, Fusha Panaireve can be mentioned, where the Limestone-Shale Formation is exposed mainly of Early Devonian age (from Icriodus steinachensis to Polygnathus quadratus, Polygnathus bultuncki and P. serotinus etc.). In the Muhur-Çaja subzone, the Black Shale Formation of Muhuri is dominant, which is rich in graptolites. In the Limestone Formation, in Buzmadhe, conodonts of Lochkovian age (Ozarkodina massara, O. r. remscheidensis, Icriodus cf.woschmidti etc.) have been found. The Miraveci is another section of this subzone, where the Carbonate-Shale Formation is exposed. The conodonts of this section (Polygnathus serotinus, P. quadratus, P. linguiformis, P. nothoperbonus, Pandorinellina steinhornensis miae, Pelekysgnathus serratus etc.) confirm an overturned profile, while the marly limestones (the level 100 m above the profile) contain many crinoids (Scyphocrinites elegans), which can be used as a marker for the entire Korabi zone. In the Kalisi profile (in the same subzone), the Marly Slate Formation is exposed with conodonts of Lochkovian- Pragian age (Ozarkodina r. remscheidensis, Ancyrodelloides cf. eleonora, Icriodus steinachensis etc.). In the Gashi zone, the schistose-carbonatic deposits in which Pterospathodus amorphognathoides (Llandoverian/Wenlockian age) fauna is determined are the oldest Palaeozoic deposits. The Triassic deposits are overlain in all the above-mentioned geological zones.Theoldest formation is the Han Bulog Limestone Formation of Spathian-Lower-Middle Anisian. This formation is more widespread in the Mirdita zone and its age is proved by species of Neospathodus (waageni) and Triassospathodus (trangularis, homeri etc.), while at the base of the Anisian, Chiosella timorensis etc., are encountered and a little bit above Nicoraella kockeli of Middle Anisian age. The Triassic is characterized by the emphatic facial changes from the east (Korabi zone) towards the west (Krasta-Cukali zone). Palaegeographically, it is dominated by continental slope facies or pelagic facies. In the Mirdita and Krasta-Cukali zones, the Middle Triassic is represented by the Effusive and Radiolarite Formation with minor carbonates, which have a poor content of conodonts; however the top of Ladinian to Cordevolian is documented by the presence of Budurovignathus mungoensis, B. diebeli etc. The Upper Triassic is characterized by the dominance of the Platy Limestone Formation in almost all of the studied zones. The majority of conodonts belongs to some species of these genera: Paragondolella (P. polygnathiformis = base of Carnian), Carnepigondolella nodosa = top of Carnian) and especially Epigondolella, Metapolygnathus, Mockina (Me. primitius, E. abneptis, Mo. postera to Mo. bidentata = Norian) and Misikella hernsteini = top of Norian. Up to now, the uppermost Norian to Rhaetian is documented only in the Gashi zone (Oncodella paucidentata).
A new plesiosaur taxon, Nichollsia borealis, gen. et sp. nov., from the Wabiskaw Member of the Clearwater Formation (Lower Cretaceous, Albian) of northeastern Alberta, Canada, is described. The exceptionally well-preserved, almost complete, fully articulated specimen represents the oldest known, and one of the most complete, Cretaceous plesiosaurs from North America. High resolution computed tomographic data of the skull provide detailed information regarding cranial structure. Nichollsia is compared to other Cretaceous genera, including Leptocleidus, with which it shares similar skeletal proportions, size, and the presence of a prominent dorsomedian ridge on the premaxillae. Nichollsia, however, possesses numerous autapomorphies, including the possession of a gracile, narrowly triangular skull lacking a rostral constriction, a vertically oriented Suspensorium, a squamosal vertex that lacks a prominent crest, the presence of longitudinal grooves on the lateral surface of the dentary, a relatively homodont dentition lacking caniniforms, and other unique features of the axial and appendicular skeleton. Nichollsia inhabited the Boreal Sea, the first major marine incursion into the northern part of the Western Interior Basin in the Early Cretaceous prior to the establishment of the Western Interior Seaway.
Top-cited authors
Paul Martin Sander
  • University of Bonn
Alberto C Riccardi
  • National Scientific and Technical Research Council
George D. Koufos
  • Aristotle University of Thessaloniki
Gerard R. Case
  • Mississippi Museum of Natural Science
Wighart Von Koenigswald
  • University of Bonn