The origins of modern nonmarine ostracod faunas: evidence from the Late Cretaceous and Early Palaeogene of Mongolia

The Cretaceous and Tertiary development of Mongolian non-marine ostracod faunas is reviewed. During the Late Cretaceous and Early Palaeogene, representatives of the Cypridoidea were widespread and common, Cytheroidea less so and the Darwinuloidea comparatively rare. The evolutionary history of the subfamily Talicyprideinae is considered, with reference to the genera Talicypridea, Altanicypris, Khandiaand Bogdocypris. It is suggested that the extinct Talicyprideinae were related to the mid-Cretaceous to Recent subfamily Cypridinae (e.g. the genus Cypris), both belonging to the family Cyprididae. It is shown that early representatives of the Cyprididae, one of the most diverse non-marine cypridoidean families today, were present from Early Cretaceous onwards (e.g. Lycopterocypris, Mongolocypris), alongside the dominant Cretaceous cypridoideans, the Cyprideidae (e.g. Cypridea), which became extinct in the Palaeogene.     

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.     

The ontogeny of appendages of Heterocypris salina (Brady, 1868) Ostracoda (Crustacea)

The post-embryonic development of the appendages of the Cyprididae ostracod Heterocypris salina (Brady, 1868) are described in detail and compared with those of other podocope species documented in previous studies. Generally, the appearence of limbs during onotgeny of H. salina is similar to that of other species, but small differences in limb morphologies were identified between H. salina and other Cyprididae species, including other Heterocypris species. Some features appear either earlier or later in the development of H. salina compared with other species, even species of the same genus. These features may be useful characters for phylogenetic analyses at the genus and family levels.     

Ostracods from the marginal coastal Lower Cretaceous (Aptian) of the Central Tunisian Atlas (North Africa): Paleoenvironment,biostratigraphy and paleobiogeography

This work provides the first detailed taxonomic study of ostracod species from the Lower Cretaceous (Aptian) marginal coastal deposits of the Central Tunisian Atlas, the Kebar Formation, as well as biostratigraphic, paleoecological and paleobiogeographic implications. The ostracod fauna provides new insights into the depositional environment and biostratigraphic framework of the Kebar Formation, and is represented mainly by freshwater and brackish-water species among them, Perissocytheridea tunisiatlasica nov. sp., is newly described. The environmental setting of this formation comprises marginal-littoral conditions in its lower part, thus not exclusively non-marine/continental as assumed previously. The ostracod associations from the studied locality, Jebel Ksaïra, indicate a minimum age of Early Aptian as recently attributed to the lower member of the Kebar Formation based on charophytes (presence of Late Barremian to Early Aptian Globator maillardii var. biutricularis Vicente and Martín-Closas, 2012), whereas an Early Albian age had been previously assigned to the Jebel Kebar site. The relative sea-level fall documented in the lower member of the Kebar formation at Jebel Ksaïra might correspond to the 3rd order cycle major eustatic sea-level fall event starting at the base of the Aptian. Paleobiogeographically, the non-marine ostracod fauna newly discovered in the Kebar Formation shows some affinities to contemporaneous faunas of southern and western Europe, e.g. that of the uppermost Weald Clay Group of southern England (Cypridea fasciata subzone of Horne, 1995), West Africa, and possibly to eastern South America (Brazil). Hence, the studied ostracods further support the hypothesis of supraregional faunal exchange by passive ostracod dispersal during the Early Cretaceous – between Europe and Northern Africa on the one hand, and eastern South America/western Africa and North Africa on the other hand. This leads to the hypothesis that the Peri-Tethyan islands could have worked as effective bridges for non-marine ostracods to become widely dispersed passively by “island-hopping” of larger animals and thus, ultimately, facilitated intercontinental faunal exchanges between South America and Europe – potentially even Asia – via North Africa during the Early Cretaceous.     

Découverte d’une nouvelle faune d’âge cénomanien dans la région de Forthassa (Atlas saharien occidental,Algérie) : Implications biostratigraphiques et paléoenvironnementales

The upper Cretaceous of the eastern part of the Ksour Mountains (Western Saharan Atlas, Algeria) is classically subdivided into three fossiliferous lithostratigraphic formations: El Rhelida (lower Cenomanian), Mdaouer (lower-middle Cenomanian) and Rhoundjaïa (upper Cenomanian-lower Turonian). The western part of the Ksour Mountains, which is less documented and poorly known, is here the subject of a detailed sedimentological and palaeontological study. Near Hassi Djeifa locality (Forthassa) the upper Cretaceous is represented by the upper part of Mdaouer Formation and by the lowermost part of Rhoundjaïa Formation. The deposits attributed to the Mdaouer Formation are composed of reddish or green marlstone intercalated by biolaminated limestone, bioclastic limestone with gastropods and bivalves, and sandstone. The selachians (Mafdetia tibniensis, Baharipristis bastetiae), pycnodontiform fishes, and ostracod fauna (Damonella spp., Ilyocypris? sp., Cypridea sp., Paracypria? sp.) coming from marly beds are studied in detail. The two selachian species (Order of Rajiformes) were so far restricted to the Early Cenomanian of Egypt. Our sedimentological and palaeontological data support a probable Early Cenomanian age of the studied deposits and indicate a coastal plain palaeoenvironment continually influenced by the action of tide.     

The effect of environmental change on early Aptian ostracods faunas in the Wessex Basin,southern England

A major phase of transgression in the Wessex Basin (southern England) during the earliest Aptian resulted in the collapse of the generally fresh water Barremian environment and the initiation of the marine milieu.Cypridea-rich faunas in the Shepherd's Chine Member (Vectis Formation), were gradually replaced by faunas dominated by Sternbergella cornigera, Mantelliana mantelli and Theriosynoecum fittoni. This change is interpreted as indicating that salinities had passed from fresh-oligohaline to meso- and pliohaline and that ephemeral water bodies were replaced by more widespread, permanent, lagoonal waters. The ostracods from the highest part of the Vectis Formation appear to be heralding the major transgression that was about to engulf the Wessex Basin.The marine incursion during the obsoletus Ammonite Subzone brought with it newly formed environmental niches that were rapidly occupied by microfaunas. Several ostracod species are interpreted as euryhaline, but others appear to have been restricted to marine or near marine salinities. The earliest marine ostracod faunas were recorded from the Perna Bed Member, Isle of Wight, and include abundant Asciocythere albae and frequent to common Schuleridea derooi, Neocythere gottisi, N. bordeti and Cytherelloidea sp. Other species include rare Cythereis geometrica, C. semiaperta, Eocytheropteron stchepinskyi and Protocythere croutesensis. In addition, elsewhere in southern England, Protocythere mertensi langi, Dolocytheridea intermedia, Paranotacythere (P.) oertlii and P. (P.) atypica occur. The relationship of this earliest Aptian population with that of the Paris Basin cannot be mistaken.     

Mid-Cretaceous/Albian (Cretaceous) ostracod assemblages from NW Hungary reflecting deep marine,nearshore and non-marine environments

The Albian sediments of the Transdanubian Range in Hungary were deposited in non-marine to fully-marine environments. The studied sections revealed diverse benthic ostracod faunas with moderately-preserved specimens. Forty-six taxa are identified and Cypridea zalanyii n. sp. is newly described. The detailed palaeoecological study of these ostracod faunas provided an opportunity to distinguish eight assemblages. The assemblages include limnic, brackish lagoon, shallow marine, reef and low oxygenated semi-enclosed basin environments in the Northern Tethys region we investigated. This work contributes to the knowledge about Albian non-marine faunas from Europe and explores ecological requirements of brackish faunas.     

Cenomanian ostracods of the Tarfaya upwelling region (Morocco) as palaeoenvironmental indicators

Changes in ostracod occurrence and assemblage composition from the Cenomanian of the Tarfaya Basin (Morocco) are investigated in order to evaluate their potential for palaeoenvironmental analyses of Cretaceous upwelling regions. Most frequent genera found at Tarfaya are Brachycythere, Veenia, Reticulocosta, Cytherelloidea, and Nigeroloxoconcha. Assemblages found at Tarfaya are characterised by low diversities. Successive appearance of assemblages dominated by these genera represents a depth gradient, corresponding to the results of the performed correspondence analysis. Ostracods are most abundant if associated either with moderate food supply and sufficient oxygenation or high food supply and high oxygenation. They disappear almost completely during permanent oxygen deficiency and are, contrary to benthic foraminifera, less frequent during periods of enhanced food supply. Species of the genus Brachycythere appear to be more sensitive to oxygen deficiency than other genera. Reticulocosta and Cytherelloidea avoid strong food pulses and are probably better adapted to oxygen depletion than other genera. Ostracods appear to be powerful environmental indicators for sea-level changes, oxygenation or food supply in Late Cretaceous upwelling settings, such as in the Cenomanian Tarfaya Basin.     

A longirostrine tyrannosauroid from the Early Cretaceous of China

The fossil record of tyrannosauroid theropods is marked by a substantial temporal and morphological gap between small-bodied, Barremian taxa, and extremely large-bodied taxa from the latest Cretaceous. Here we describe a new tyrannosauroid, Xiongguanlong baimoensis n. gen. et sp., from the Aptian–Albian Xinminpu Group of western China that represents a phylogenetic, morphological, and temporal link between these disjunct portions of tyrannosauroid evolutionary history. Xiongguanlong is recovered in our phylogenetic analysis as the sister taxon to Tyrannosauridae plus Appalachiosaurus, and marks the appearance of several tyrannosaurid hallmark features, including a sharp parietal sagittal crest, a boxy basicranium, a quadratojugal with a flaring dorsal process and a flexed caudal edge, premaxillary teeth bearing a median lingual ridge, and an expanded axial neural spine surmounted by distinct processes at its corners. Xiongguanlong is characterized by a narrow and elongate muzzle resembling that of Alioramus. The slender, unornamented nasals of Xiongguanlong are inconsistent with recent hypotheses of correlated progression in tyrannosauroid feeding mechanics, and suggest more complex patterns of character evolution in the integration of feeding adaptations in tyrannosaurids. Body mass estimates for the full-grown holotype specimen of Xiongguanlong fall between those of Late Cretaceous tyrannosaurids and Barremian tyrannosauroids, suggesting that the trend of increasing body size observed in North American Late Cretaceous Tyrannosauridae may extend through the Cretaceous history of Tyrannosauroidea though further phylogenetic work is required to corroborate this.     

Embryos,polyps and medusae of the Early Cambrian scyphozoan Olivooides

The Early Cambrian organism Olivooides is known from both embryonic and post-embryonic stages and, consequently, it has the potential to yield vital insights into developmental evolution at the time that animal body plans were established. However, this potential can only be realized if the phylogenetic relationships of Olivooides can be constrained. The affinities of Olivooides have proved controversial because of the lack of knowledge of the internal anatomy and the limited range of developmental stages known. Here, we describe rare embryonic specimens in which internal anatomical features are preserved. We also present a fuller sequence of fossilized developmental stages of Olivooides, including associated specimens that we interpret as budding ephyrae (juvenile medusae), all of which display a clear pentaradial symmetry. Within the framework of a cnidarian interpretation, the new data serve to pinpoint the phylogenetic position of Olivooides to the scyphozoan stem group. Hypotheses about scalidophoran or echinoderm affinities of Olivooides can be rejected.     

The Phylogenetic Affinities of the Enigmatic Mammalian Clade Gondwanatheria

Gondwanatheria is a group of extinct mammals known from the Cretaceous and Paleogene of Gondwana. Resolution of the phylogenetic affinities of gondwanatherians has proven problematical, with the group currently considered Mammalia incertae sedis. We briefly review the morphology of known gondwanatherians, and argue that isolated upper premolars and a partial dentary preserving a blade-like p4 originally referred to the ferugliotheriid gondwanatherian Ferugliotherium windhauseni but subsequently identified as Multituberculata incertae sedis do indeed belong to F. windhauseni. We also suggest that the recently described ?cimolodontan multituberculate Argentodites coloniensis, based on an isolated lower premolar, may in fact be an unworn p4 of Ferugliotherium or a closely related taxon. We present the first phylogenetic analyses to include gondwanatherians, using maximum parsimony and Bayesian methods. Both methods place Ferugliotherium and sudamericid gondwanatherians in a clade with cimolodontan and “plagiaulacidan” multituberculates, although relationships within this clade are largely unresolved. The Gondwanatheria + Multituberculata clade supported here may reflect the convergent evolution of similar dental features, but it is the best supported hypothesis based on currently available data. However, denser sampling of multituberculate taxa and the discovery of more complete gondwanatherian fossils will be required to clarify the precise relationship between gondwanatherians and multituberculates, specifically to determine whether or not gondwanatherians are members of Multituberculata. We hypothesize that the anterior molariforms of sudamericid gondwanatherians evolved from blade-like precursors similar to the p4 of Ferugliotherium, possibly in response to the appearance of grasses in Gondwana during the Cretaceous.     

Systematics and evolution of the genus Torrubiella (Hypocreales, Ascomycota)

Torrubiella is a genus of arthropod-pathogenic fungi that primarily attacks spiders and scale insects. Based on the morphology of the perithecia, asci, and ascospores, it is classified in Clavicipitaceae s. lat. (Hypocreales), and is considered a close relative of Cordyceps s. 1., which was recently reclassified into three families (Clavicipitaceae s. str., Cordycipitaceae, Ophiocordycipitaceae) and four genera (Cordyceps s. str, Elaphocordyceps, Metacordyceps, and Ophiocordyceps). Torrubiella is distinguished morphologically from Cordyceps s. lat. mainly by the production of superficial perithecia and the absence of a well-developed stipitate stroma. To test and refine evolutionary hypotheses regarding the placement of Torrubiella and its relationship to Cordyceps s. lat., a multi-gene phylogeny was constructed by conducting ML and Bayesian analyses. The monophyly of Torrubiella was rejected by these analyses with species of the genus present in Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitaceae, and often intermixed among species of Cordyceps s. lat. The morphological characters traditionally used to define the genus are, therefore, not phylogenetically informative, with the stipitate stromata being gained and/or lost several times among clavicipitaceous fungi. Two new genera (Conoideocrella, Orbiocrella) are proposed to accommodate two separate lineages of torrubielloid fungi in the Clavicipitaceae s. str. In addition, one species is reclassified in Cordyceps s. str. and three are reclassified in Ophiocordyceps. The phylogenetic importance of anamorphic genera, host affiliation, and stipitate stromata is discussed.     

The ontogeny of the cypridid ostracod Eucypris virens (Jurine, 1820) (Crustacea,Ostracoda)

The chaetotaxy (shape, structure and distribution of setae) of appendages and valve allometry during the post embryonic ontogeny of the cyprididine ostracod Eucypris virens are described. It is shown that the basic ontogenetic development of E. virens is very similar to that of other species of the family Cyprididae. During ontogeny, the chaetotaxy shows continual development on all podomeres of the limbs with the exception of the last podomere on the antennulae. The long setae on the exopodite and protopodite of the antennae have a natatory function until the actual natatory setae develop in later instars. Aesthetascs (presumed chemoreceptors) ya and y3 are the first to develop and may have an important function in the first instars. Cyprididae require a pediform limb in the posterior of the body presumably to help them to attach to substrates and this is reflected by the pediform nature of one limb at all times throughout all instars. This study has also shown that the fifth limb is most probably of thoracic origin and hence ostracods have only one pair of maxillae.     

Two new synonyms in Heteranthera (Pontederiaceae,Commelinales)

Hydrothrix and Scholleropsis, two segregate monospecific genera placed within the Heteranthera s.l. clade, are here transferred to Heteranthera based on phylogenetic and morphological data. A brief discussion on the morphology and affinities of Heteranthera s.l. is given, along with the designation of lectotypes for the two new transfers.     

Comptoniaster adamsi nov. sp. (Echinodermata, Asteroidea) from the middle Cretaceous of Texas and its phylogenetic position

Comptoniaster adamsi nov. sp. (Asteroidea, Valvatida, Goniasteridae) is described from the middle Cretaceous (Cenomanian-Turonian) Britton Formation of northcentral Texas, USA. The new species provides the focus for an exploratory cladistic analysis of Mesozoic asteroids of the Comptoniaster-Tylasteria Group sensu G. Breton. The systematics of Mesozoic goniasterids has relied heavily on the morphology of marginal ossicles, which generally are the best-preserved elements of the skeleton. Unfortunately, marginal ossicular data are scanty for most species because ossicles tend to be morphologically simple yet varied even within individuals, and few even partially articulated specimens are available to provide more comprehensive information. Further, both plesiomorphy and homeomorphy have been important. Because of limited available data, phylogenetic reconstruction here is preliminary. Nevertheless, a number of taxon groupings recognized in the literature are recovered, and stratigraphic distribution provides some support for results. Data unfortunately are particularly incomplete for species of Comptoniaster, the focus of the study. Comptoniaster adamsi nov. sp. clustered with three other species assigned to the genus, including the type, all Cretaceous in age. Jurassic species of Comptoniaster are more widely distributed in the analysis, perhaps reflecting an early stage in diversification or perhaps suggesting the need for species assignment reassessment, but also reflecting the limited available data.     

A new abelisaurid dinosaur from the Late Cretaceous of southern France: Palaeobiogeographical implications

The Abelisauridae are a family of mainly Cretaceous theropod dinosaurs with a wide distribution across the Gondwanan land masses. Although their presence in Europe was reported twenty-five years ago, it has often been considered as controversial largely because of the incompleteness of the available specimens. We report here the discovery of well-preserved abelisaurid material, including a highly diagnostic braincase, at a Late Cretaceous (late Campanian) locality in the Aix-en-Provence Basin, near the eponym city in south-eastern France. A new abelisaurid taxon is erected, Arcovenator escotae gen. nov., sp. nov., on the basis of cranial and postcranial material. A phylogenetic analysis reveals that the new Abelisauridae from Provence is more closely related to taxa from India and Madagascar than to South American forms. Moreover, Genusaurus, Tarascosaurus and the previous Late Cretaceous discoveries are identified as basal abelisaurids. Contrary to previously proposed palaeobiogeographical models of abelisaurid evolution, the presence of the new taxon in Europe suggests that Europe and Africa may have played a major role in abelisaurid dispersal, which apparently involved crossing marine barriers.