Zonocypris digitalis (Ostracoda, Crustacea), nouvelle espèce du Fuvélien (Campanien continental) de Provence (sud-est France)

Many specimens of non-marine Ostracodes, especially the new species Zonocypris digitalis were recovered from continental deposits of fuvelian (Campanian) age at Auriol (Provence, south-east France). First species of that genus described in the Cretaceous of southern Europe, Z. digitalis is associated with Charophytes and mainly Gastropodes remains, thus providing confirmation of the datation proposed and age of the studied outcrops. Z. digitalis may be integrated within the current biostratigraphic scale which is accepted as valid for the non-marine Upper Cretaceous of the above mentioned area.     

A mosasaur from the Cenomanian of Russia

The premaxilla of a mosasauroid lizard from the Lysaya Gora 3 locality in Saratov (Upper Cretaceous, Cenomanian) is described. To date, the oldest known mosasaur remains have been dated Turonian. The premaxilla is most similar in morphology to that of Russellosaurus from the Turonian of the United States; however, the absence of sufficient diagnostic characters only allows its attribution to Mosasauridae indet.     

On the systematic position of the Early Cretaceous fern genus “Athyrium”

The oldest fossils assigned to Athyrium (mostly based on the sorus morphology) comprise fronds and spores from the Lower Cretaceous of Northeast Asia. However, most molecular dating suggests that extant Athyrium diverged from its sister genus during the Eocene or later, implying that the Cretaceous fossils probably belong to another polypodiaceous taxon. By examining the sorus morphology of extant genera related to the family Athyriaceae, we found that the primary diagnostic feature for assigning the Cretaceous fossils to Athyrium, i.e., the sorus shape, is common to the entire extant family, or plesiomorphic for the genus. As the fronds are more commonly preserved than the reproductive parts, we compared the fossil frond morphology with those of living taxa of the family that is divided into two types. The Cretaceous fossil we examined here bears the frond’s costal groove characters on adaxial side, which is more closely related to that of the Deparia-clade instead of the clade including Athyrium and other genera of the family. The observation is further confirmed by the cladistic analysis using morphological characters. The systematic position of the Early Cretaceous “Athyrium” was resolved as a stem member of the total Athyriaceae using a tip-dating approach with the Fossilized Birth-Death model in a Bayesian framework. Our study suggests that Early Cretaceous fossils previously assigned to Athyrium require taxonomic revision.     

Lowermost occurrence of ostracod Cypridea species in East Asia and implications for the non-marine Jurassic/Cretaceous boundary

Cypridea Bosquet, 1852 is a non-marine ostracod genus of the Superfamily Cypridoidea, and the extinct Family Cyprideidae, which achieved high diversity in the Early Cretaceous. This genus plays an important role in the subdivision and correlation of strata, as well as in paleogeographic and paleoclimatic studies. Cypridea species are remarkably abundant and diverse, and are extensively distributed across East Asia. However, the lowermost occurrence of Cypridea species (LOOC) in East Asia is still being debated, varying from the Upper Jurassic to Lower Cretaceous. Here, we aim to conduct a preliminary investigation of the Cypridea-bearing strata of East Asia (China, Mongolia, Korea and Japan), and attempt to update the strata correlation, based on new progress of the ostracod correlations, as well as the progress of other research methods on the relative Jurassic/Cretaceous (J/K) strata of these areas. Results show that the LOOCs in most basins of East Asia are documented in Lower Cretaceous (～Berriasian) strata. However, Cypridea species are extremely rare near the J/K boundary interval but flourish until Valanginian–Hauterivian in most basins of East Asia. Therefore, we propose that the LOOC in each corresponding basin of East Asia can be used as an auxiliary marker of the non-marine J/K boundary. Cypridea species may have travelled first from Africa (Kimmeridgian) to Europe (J/K period), and then East Asia (Early Cretaceous), which resulted in the LOOC in East Asia later than in the other continents.     

珠三角河网链状硅藻物种组成及生态特征

珠三角河网水域是珠江之水流入南海的必经之地,于2012年和2015年对该水域的链状硅藻的时空特征及其影响因素进行了分析。共发现链状硅藻18种(包括变种和变型),颗粒沟链藻是该水域的绝对优势种,也是该区域水体富营养化的重要指示物种。总生物量的时间变化模式呈现枯水期差异较大,丰水期差异较小的特点,主要是受到径流量、透明度和水温差异的影响;空间特征主要表现为广州市周边站位的生物量明显偏高,主要受水体富营养化的影响。不同链状硅藻的相对百分组成显示,颗粒沟链藻是绝对优势种,变异直链藻易在枯水期与其形成竞争优势。沟链藻属的链长一般大于直链藻属,这主要得益于其形态结构较稳固的优势;此外,透明度、营养盐和pH值等也是影响链长的重要因素。     

Upper Cretaceous paleogeography of the Central Southern Pyrenean Basins (Catalonia, Spain) from microfacies analysis and charophyte biostratigraphy

The most extensive latest Cretaceous deposits of the Pyrenees are non-marine facies traditionally called “Garumnian”, which represent the first continentalization of the Pyrenean Foreland Basins. The age and paleogeography of the basal Garumnian facies in the different parts of the Pyrenean Basin has been a matter of debate. Charophyte biostratigraphy and microfacies analysis suggest that the continentalization was diachronous in the Central Southern Pyrenean basins, i.e., between the Àger and Tremp basins, and the emersion progressed from south to north. In the Àger Basin, to the south, the first Upper Cretaceous non-marine rocks are represented by the La Maçana Formation. This unit is mainly formed by freshwater lacustrine limestones organized into hundreds of shallowing-upwards sequences ranging from deeper lacustrine facies, through marginal, well-illuminated environments dominated by characean meadows, and finishing with lakeshores dominated by clavatoracean meadows. The charophyte assemblage from the La Maçana Fm is mainly formed by Peckichara cancellata, P. sertulata, Microchara cristata, M. parazensis, Platychara caudata, and Clavator brachycerus, which belong to the Peckichara cancellata charophyte biozone (Late Campanian). In contrast, in the Tremp Basin, located to the north, the beginning of the non-marine sedimentation is organized into a few cycles of the well-known La Posa Fm. These cycles begin with brackish deposits formed by thick marls with euryhaline molluscs at the base, followed by lignite and brackish to freshwater limestones. The brackish facies are dominated by porocharaceans. The charophyte assemblage of the La Posa Formation is formed by Feistiella malladae, Peckichara sertulata, Microchara cristata, and Clavator brachycerus, which belong to the Septorella ultima charophyte biozone (Early Maastrichtian).     

Triuridaceae fossil flowers from the Upper Cretaceous of New Jersey

We report here on a series of fossil flowers exhibiting a mosaic of characters present in the extant monocot family Triuridaceae. Phylogenetic analyses of morphological data from a broad sample of extant monocots confirm the affinities of the fossils with modern Triuridaceae. The fossil flowers were collected from outcrops of the Raritan Formation (Upper Cretaceous, ～90 million years before present), New Jersey, USA. These are the oldest known unequivocal monocot flowers. Because other reports of "earliest" monocots are all based on equivocal character suites and/or ambiguously preserved fossil material, the Triuridaceae fossils reported here should also be considered as the oldest unequivocal fossil monocots. Flowers are minute and unisexual (only male flowers are known); the perianth is composed of six tepals, lacking stomata. The unicyclic androecium is of three stamens with dithecal, monosporangiate, extrorse anthers that open by longitudinal slits. The endothecium has U-shaped type thickenings. Pollen grains are monosulcate. The triurid fossil flowers can be separated into three distinctive species. On the basis of phylogenetic analyses of morphological characters, the fossil taxa nest within the completely saprophytic achlorophyllous Triuridaceae supporting the interpretation that the extinct plants were also achlorophyllous and saprophytic. If so, this represents the earliest known fossil occurrence of the saprophytic/mycotrophic habit in angiosperms.     

Histological study of karaurids,the oldest known (stem) urodeles

Little is known about the initial phases of lissamphibian history (before the Cretaceous), because their fossil record is quite scanty. Only the morphology of the earliest members has been investigated, although other sets of data, from bone microanatomy and histology, are known to yield valuable paleobiological information. In the present study, we provide the first histological and microanatomical data on the oldest known stem-urodeles, the karaurids, from the Middle Jurassic. Three humeri from the Upper Bathonian, Oxfordshire, referred to juvenile or subadult individuals of Marmorerpeton and to an unnamed caudate of undetermined (but obviously non-larval) ontogenetic stage, were sampled in order to shed new light on the habitat and ontogeny of these basal caudates. The great compactness of the three humeri suggests that these salamanders were aquatic. The presence of extensive amounts of calcified cartilage in the humeri greatly strengthens the case for the presence of neoteny in these taxa, a suggestion that had initially been made on the basis of a few morphological characters. This constitutes the oldest known occurrence of neoteny in lissamphibians. Finally, bone histology reveals that the growth of Marmorerpeton and the related unnamed caudate was fairly slow and cyclic, a characteristic of extant lissamphibians.     

Ostracod range charts as a chronoecologic tool

Using a linear time scale and equating the durations of species with those of their ecologic niches, range charts of ostracods show ecologic events. As a non-marine example, the Upper Miocene record of the genusCyprideis shows asymptotic freshening of the Central Paratethys. Duration charts of British Jurassic and Cretaceous shallow marine species reflect shore-line movements which generally do, but sometimes do not correlate with global sea-level changes.Charts of all (marine and non-marine) ostracod species distinguish regressions due to progradation during a sea-level rise or highstand from those caused by falling sea-level.Global sea-level changes not only directly induce large-scale creation and destruction of shallow-water benthic niches, but also will drastically affect pelagic and terrestrial environments. The ostracod record discussed in this paper suggests that eustacy is an important driving force behind macroevolution.