Serpulid microbialitic bioherms from the upper Sarmatian (Middle Miocene) of the central Paratethys Sea (NW Hungary) – witnesses of a microbial sea

We present previously unknown stacked bowl-shaped bioherms reaching a size of 45 cm in diameter and 40 cm in height from weakly solidified peloidal sand from the upper Sarmatian of the Paratethys Sea. The bioherms were mostly embedded in sediment, and the “growth stages” reflect a reaction on sediment accretion and sinking into the soft sediment. The bioherms are spirorbid–microclot–acicular cement boundstones with densely packed Janua tubes surrounded by microclots and acicular cement solidifying the bioherm. The surrounding sediment is a thrombolite made of peloids and polylobate particles (mesoclots) which are solidified synsedimentarily by micrite cement and dog-tooth cement in a later stage. The shape of the bioherms reflects a series of growth stages with an initial stage (“start-up stage”) followed by a more massive “keep-up stage” which grades into a structure with a collar-like outer rim and a central protrusion and finally by a termination of growth (“give-up stage”). The setting was a shallow subtidal environment with normal marine or elevated saline, probably oligotrophic, conditions with an elevated alkalinity. The stacked bowl-shaped microbialites are a unique feature that has so far been undescribed. Modern and Neogene microbialite occurrences are not direct analogues to the described structures, but the marine examples, like in The Bahamas, Shark Bay and the Persian Gulf, offer insight into their microbial composition and environmental parameters. The microbialites and the surrounding sediment document a predominance of microbial activity in the shallow marine environments of the Paratethys Sea during the late Middle Miocene, which was characterized by a warm, arid climate.</p

Revision of the Cretaceous shark Protoxynotus (Chondrichthyes, Squaliformes) and early evolution of somniosid sharks

Due to the peculiar combination of dental features characteristic for different squaliform families, the position of the Late Cretaceous genera Protoxynotus and Paraphorosoides within Squaliformes has long been controversial. In this study, we revise these genera based on previously known fossil teeth and new dental material. The phylogenetic placement of Protoxynotus and Paraphorosoides among other extant and extinct squaliforms is discussed based on morphological characters combined with DNA sequence data of extant species. Our results suggest that Protoxynotus and Paraphorosoides should be included in the Somniosidae and that Paraphorosoides is a junior synonym of Protoxynotus. New dental material from the Campanian of Germany and the Maastrichtian of Austria enabled the description of a new species Protoxynotus mayrmelnhofi sp. nov. In addition, the evolution and origin of the characteristic squaliform tooth morphology are discussed, indicating that the elongated lower jaw teeth with erected cusp and distinct dignathic heterodonty of Protoxynotus represents a novel functional adaptation in its cutting-clutching type dentition among early squaliform sharks. Furthermore, the depositional environment of the tooth bearing horizons allows for an interpretation of the preferred habitat of this extinct dogfish shark, which exclusively occupied shelf environments of the Boreal- and northern Tethyan realms during the Late Cretaceous.publishedVersio

Chronology and integrated stratigraphy of the Miocene Sinj Basin (Dinaride Lake System, Croatia)

a b s t r a c t a r t i c l e i n f o In the Miocene, the intra-montane basins of the Dinaric Mountain Chain harbored a series of long-lived lakes constituting the so-called Dinaride Lake System. The thick lacustrine sedimentary records of these lakes provide an excellent opportunity to study evolution and radiation of mollusks in an isolated environment. The 500 m thick infill that accumulated in the Sinj Basin is one of the key records because of its excellent mollusk preservation. Recent studies on the depositional history, pollen assemblages and large mammals have enhanced the understanding not only of Lake Sinj, but also of the regional climatic developments and faunal migratory patterns. A reliable chronology of the development of Lake Sinj, which is crucial for global correlation of its endemic realm, was still lacking. In this paper we present a detailed time-frame for the Miocene Sinj basin based on palaeomagnetic and 40 Ar/ 39 Ar data. We conclude that deposition took place between 18.0 to 15.0 Ma, a time span that correlates with the upper Burdigalian and lower Langhian Mediterranean stages and Ottnangian, Karpatian and lowermost Badenian Paratethys stages. Furthermore, we determined the timing of several events in mollusk evolution, important for correlation across the Dinarides. An age of 15.0 Ma is attributed to the large mammals Conohyus and Gomphotherium, preserved in the upper part of the basin stratigraphy

The evolution of autotomy in leaf-footed bugs

Sacrificing body parts is one of many behaviors that animals use to escape predation. This trait, termed autotomy, is classically associated with lizards. However, several other taxa also autotomize, and this trait has independently evolved multiple times throughout Animalia. Despite having multiple origins and being an iconic antipredatory trait, much remains unknown about the evolution of autotomy. Here, we combine morphological, behavioral, and genomic data to investigate the evolution of autotomy within leaf-footed bugs and allies (Insecta: Hemiptera: Coreidae + Alydidae). We found that the ancestor of leaf-footed bugs autotomized and did so slowly; rapid autotomy (<2 min) then arose multiple times. The ancestor likely used slow autotomy to reduce the cost of injury or to escape nonpredatory entrapment but could not use autotomy to escape predation. This result suggests that autotomy to escape predation is a co-opted benefit (i.e., exaptation), revealing one way that sacrificing a limb to escape predation may arise. In addition to identifying the origins of rapid autotomy, we also show that across species variation in the rates of autotomy can be explained by body size, distance from the equator, and enlargement of the autotomizable appendage

Late Messinian mollusks and vertebrates from Moncucco Torinese, north-western Italy. Paleoecological and paleoclimatological implications

The systematic analysis of more than 20,000 fossils (Vertebrata and Mollusca), recovered from the post-evaporitic Messinian (5.41-5.33 Ma) succession of Moncucco Torinese (NW Italy), resulted in the identification of 90 vertebrate and 65 mollusk taxa that provide additional information about the paleoecological context and the paleoenvironmental settings of NW Italy slightly before the Mio-Pliocene boundary. Our analyses indicate a landscape dominated by open woodlands within a mosaic environment also including closed canopy forests, grasslands, rocky outcrops and limited water edges. The wide spectrum of habitats may have had a prominent role in determining the high paleobiodiversity observed in the paleocommunity of Moncucco Torinese. Slight variations in the abundances of the most common rodent species over the investigated succession are probably related to local changes in the paleolandscape. From a paleoclimatic point of view, the overall information provided by the fauna indicates mesic conditions in a subtropical climate, which is also consistent with the interpretation derived from paleobotanical and sedimentological analyses for the latest Messinian of Northern Italy