Turonian flora from the fossiliferous flints of Châtellerault (western France)

Three new localities yielding fossiliferous flints are reported from the Châtellerault area (Vienne, western France). They include one archaeological site (La Grande Vallée) and two zones with alterite deposits (L’Aunas and Les Bariollières). Broken surfaces of flint nodules show co-occurrence of marine invertebrates such as bryozoans, echinoids (Micraster Agassiz, Orthopsis Cotteau), gastropods (Acteonella d’Orbigny), rudists, and sponges. The association of Acteonella, Micraster and Orthopsis confirms the Turonian age (Upper Cretaceous) of the fossil assemblage. The marine invertebrates co-occur with plant macroremains including fragments of conifer leafy axes such as Brachyphyllum? Brongn., Frenelopsis (Schenk) emend. J. Watson and Geinitzia Endl., as well as fragments of angiosperm leaves. Plant remains are preserved as siliceous permineralizations, showing the gross morphology and all tissues in three dimensions. The fossil assemblage suggests that sediments were deposited proximally along the shoreline in shallow environment influenced by both continental and marine inputs. This coastal area was close to a conifer-dominated forest ecosystem, Geinitzia being probably one of the main components of the flora.     

The infaunal echinoid Micraster: Taphonomic pathways indicated by sclerozoan trace and body fossils from the Upper Cretaceous of northern Spain

Micraster echinoid fossils are common in the Upper Cretaceous Olazagutía Formation of northern Spain. Tests frequently record sclerobiont signatures (including bioerosion and encrustation), left by reaction and/or coaction phenomena. Among bioerosion structures, Oichnus simplex, O. paraboloides, O. ichnosp. A, Trypanites solitarius, Rogerella ichnosp. indet., Centrichnus cf. eccentricus, Maeandropolydora ichnosp. indet. and fungal microborings are found, as well as pits and fractures. As for sclerozoan body fossils, bivalves (Dimyidae, Anomiidae, Plicatulidae and other Pectinacea), polychaete annelids (serpulids and spirorbids), lituolid foraminiferans (Haddoniidae and Coscinophragmatidae) and bryozoans (cheilostomate ones and others undetermined), as well as other less common groups, have been identified. Taphonomic paths followed by Micraster tests are analysed, based on conservation state and degree of colonisation and sedimentary filling. This allows to distinguish between accumulated fossils and non accumulated ones (including resedimented and reelaborated ones).     

New xylological data and the biogeography of the Iberian Peninsula during the Early Cretaceous

The position of the Iberian Peninsula during the Early Cretaceous, sandwiched between Laurasia and Gondwana, makes it an important area for the biogeography study of terrestrial ecosystems. Relevant data are, however, scarce. The discovery of silicified wood in the west of the Cameros Basin, in the village Hacinas (Spain), is the first record of the genus Protopodocarpoxylon in Spain and the seventh of Agathoxylon. A new species, Protopodocarpoxylon haciniensis sp. nov., is described. The anatomy of the samples studied shows that paleoclimatic conditions during the Early Cretaceous in the western part of the Cameros Basin were favorable to tree growth, with good water supply during the growth season. Although much impoverished in comparison with Western Europe, the Iberian Early Cretaceous wood floras are clearly Laurasian in affinity.     

Patterns of Fluctuating Asymmetry and Shape Variation in Chironomus riparius (Diptera,Chironomidae) Exposed to Nonylphenol or Lead

Deformities and fluctuating asymmetry in chironomid larvae have been proposed as sensitive indicators of biological stress and are commonly used to assess the ecological impact of human activities. In particular, they have been associated in Chironomus riparius, the most commonly used species, with heavy metal and pesticide river pollution. In this study, the effect of lead and 4-nonylphenol on mouthpart morphological variation of Chironomus riparius larvae was investigated by traditional and geometric morphometrics. For this purpose, first to fourth instar larvae were exposed to sediment spiked with lead (from 3.0 to 456.9 mg/kg dry weight) or 4-NP (from 0.1 to 198.8 mg/kg dry weight). Mentum phenotypic response to pollutants was assessed by four parameters: (1) the frequency of deformities, (2) fluctuating asymmetry of mentum length, (3) fluctuating asymmetry of mentum shape and (4) the mentum mean shape changes. Despite the bioaccumulation of pollutants in the chironomid’s body, no significant differences between control and stressed groups were found for mouthpart deformities and fluctuating asymmetry of mentum length. Slight effects on mentum shape fluctuating asymmetry were observed for two stressed groups. Significant mean shape changes, consisting of tooth size increase and tooth closing, were detected for lead and 4-NP exposure respectively. Those variations, however, were negligible in comparison to mentum shape changes due to genetic effects. These results suggest that the use of mentum variation as an indicator of toxic stress in Chironomus riparius should be considered cautiously.     

How Useful is Fluctuating Asymmetry in Conservation Biology: Asymmetry in Rare and Abundant Coenonympha Butterflies

It has been suggested that minor, fluctuating differences in size of bilateral traits could validly indicate individual differences in developmental stability. One plausible reason for instability to occur could be lowered population size, which has been suggested to increase fluctuating asymmetry due to inbreeding, for example. We measured seven wing asymmetries of three Coenonympha butterfly species in central Sweden. One species is abundant (nobreak C. pamphilus), one rather common (C. arcania), and one rare (C. hero). We expected that if fluctuating asymmetry is a reliable indicator of population quality and thus a useful tool for conservation purposes, the most abundant species should show lowest asymmetry and the most endangered, the highest. Contrary to our expectations, the highest wing asymmetry was found in the relatively common species C. arcania and the most abundant and rare species did not show significant differences in levels of wing asymmetry. Our results obtained from three Coenonympha species hence suggest that the use of fluctuating asymmetry as an indicator of population conservation status may be misleading. Possible increase in asymmetry of small and/or isolated populations of butterflies may be masked by local differences in environmental conditions that could have high impact on bilateral development as well.     

Neogene history of Sporolithon Heydrich (Corallinales,Rhodophyta) in the Mediterranean region

Most modern species of Sporolithon live in tropical and subtropical areas and only one species of the genus, S. ptychoides, occurs in the Mediterranean Sea. The scarce present-day populations of Sporolithon in the Mediterranean region are relics of a long history of the genus in this area since the Early Cretaceous. Analysis of data from the palaeontological literature, combined with the study of both fossil samples and Recent ones collected from Italy and Spain, shows that during the Miocene variations in the number of Sporolithon species in the Mediterranean region parallel changes in global temperature. After a maximum species richness in the Langhian (early Mid Miocene), coincident with the Miocene climatic optimum, the number of species decreased to just two before the Messinian Salinity Crisis. This marked decline follows the global cooling event that began at around 14 Ma. The closure of the connections of the Mediterranean region with the Indian Ocean during the Langhian left Mediterranean Sporolithon populations isolated from the main dispersal area of the genus. After the Messinian desiccation, a single species, S. ptychoides, re-invaded the Mediterranean Basin during the Early Pliocene and continues to inhabit this temperate sea today. The Atlantic Ocean is the most probable source of the re-invading Sporolithon plants.     

Phenotypic variability of the pearly heath, Coenonympha arcania L. (Lepidoptera, Satyridae) in natural and anthropogenically transformed habitats in the Middle and South Urals

Analysis of variation of the wing length and eyespots in Coenonympha arcania (Linnaeus, 1761) (Lepidoptera, Satyridae) in the Middle and South Urals showed greater differences between populations from the forest and steppe zones than between populations from natural habitats and those subjected to chemical and radionuclide pollution. Based on small values of the fluctuating asymmetry (FA) index in all the habitats examined, it may be concluded that C. arcania finds favorable environment in both natural and anthropogenically transformed habitats in the Middle and South Urals.     

GENOMIC COADAPTATION AND DEVELOPMENTAL STABILITY WITHIN INTROGRESSED POPULATIONS OF ENNEACANTHUS GLORIOSUS AND E. OBESUS (PISCES,CENTRARCHIDAE)

Using fluctuating bilateral asymmetry as a measure of developmental stability, we tested the hypothesis that genomic coadaptation mediates developmental stability in natural populations. Hybrid populations were more asymmetrical than populations of the parental species, and ranks of overall developmental instability were positively correlated with ranks of mean heterozygosity in these populations. The failure to find increased asymmetry in previous studies of natural hybrid populations (Jackson, 1973a, 1973b; Felley, 1980) suggests that such populations may have re-evolved coadapted genomes. Increased asymmetry in hybrid Enneacanthus populations may reflect the youthfulness of these populations.     

Ethological variations in gauge in sauropod trackways from the Berriasian of Spain

Castanera, D., Pascual, C., Canudo, J.I., Hernández, N. & Barco, J., 2012: Ethological variations in gauge in sauropod trackways from the Berriasian of Spain. Lethaia, Vol. 45, pp. 476–489. Two sauropod trackways from the Early Cretaceous (Berriasian) of the Cameros Basin (Spain) show important variations in trackway gauge, along the same trackway. These variations seem to be associated with different behaviours; on the one hand with a significant variation in the direction of travel (turning phenomena) and on the other hand with a decrease in speed, probably associated with the properties of the substrate. These variations in sauropod trackways provide the trackway gauge debate with new data, supporting the hypothesis that the walking style and substrate properties may in some cases determine this sauropod character. The study of turning sauropod trackways improves our knowledge of sauropod locomotion. □Ethology, intermediate‐gauge, sauropod trackways, substrate properties, wide‐gauge.     

Genetic variability of central–western European pine marten (Martes martes) populations

Recent studies highlighted the potential role of cryptic glacial refugia for temperate taxa in Europe beyond the Mediterranean peninsulas. To further investigate phylogeographic features of the European pine marten (Martes martes) in previously identified cryptic refugia located in central–western Europe, we analysed the hyper-variable diagnostic fragment of the mitochondrial control region in a total of 134 specimens, allowing for reliable comparisons with previous genetic studies of the species. We included samples from eight different European countries in central–western Europe (Belgium, France, Luxembourg and the Netherlands), in south–western Europe (Spain), in north–central Europe (Denmark) and in central Europe (Germany and Poland). The sequences collapsed in 17 haplotypes, which allowed us to determine the genetic composition of the pine marten populations throughout central–western Europe. Overall, our results showed that the population genetic variation, estimated by the standardised haplotype diversity, was high (0.400?≤?Hs?≤?0.762), and it was considerably higher in Germany (0.762) and the Netherlands (0.722) compared to the other countries. The nucleotide diversity was relatively low (0.002?≤?π?≤?0.016) even in Germany and the Netherlands (0.016 and 0.014, respectively), suggesting relatively small, long-term effective population sizes or severe bottlenecks. Out of the 17 haplotypes found in our study area, 13 were unique and limited to a single country: one in Denmark, one in Spain, four in Poland and seven in the Netherlands. The pairwise genetic distance ranged from 0.001 to 0.032 and did not show any evident correlation with the geographic distances between the populations. A genealogical relationship network was constructed, which provided evidence for a recent origin of many of the unique haplotypes. Approximately 82 % of the samples analysed in this study belonged to haplotypes grouped into a previously identified central–northern European phylogroup of the species. Our results support previous findings, indicating low contribution of southern refugial populations to the postglacial recolonization of central–western Europe and a predominant contribution of pine marten populations that survived the Last Glacial Maxima in cryptic northern refugia.     

Fluctuating asymmetry and inbreeding in Scandinavian gray wolves (Canis lupus)

We investigated fluctuating asymmetry in 13 traits of the skulls and jaws of historical and contemporary populations of Scandinavian gray wolves (Canis lupus). We hypothesized that there is a higher level of fluctuating asymmetry in the inbred contemporary population than in the historical population. Our analyses did not detect any difference in the level of fluctuating asymmetry as predicted. We propose different explanation for this lack of change in fluctuating asymmetry. It is assumed that a large number of studies have failed to find a positive correlation between the level of genetic stress and developmental instability and have therefore never been published, which hampers a good understanding of fluctuating asymmetry as an indicator of developmental instability. The current study is thus important in this context. The gray wolf population in Scandinavia is characterized by an extreme bottleneck followed by two and a half decades of strong inbreeding, but no associated change in fluctuating asymmetry is detected.     

New hybodont shark assemblage from the Early Cretaceous of the Basque-Cantabrian Basin

Hybodont remains from the Early Cretaceous of the Basque-Cantabrian Basin (Cantabric Range) in the North of Spain are described for the first time. This assemblage represents a highly diversified shark fauna adapted to different feeding habits. Isolated remains of six hybodont genera, namely Hybodus, Egertonodus, Planohybodus, Lonchidion, Parvodus, and Lissodus, have been recovered and described from the freshwater Vega de Pas Formation in the locality of Vega de Pas (Cantabria, Northern Spain). Most of these taxa are known from the English Wealden, making the shark fauna of the Vega de Pas 1 site the most similar assemblage to English Wealden shark fauna among any other site known in Europe.     

Habitat fragmentation promotes fluctuating asymmetry but not morphological divergence in two geckos

The process of species formation is often ignored in discussions on the conservation of biodiversity. Yet the clearance of vegetation may promote divergence among populations of a species through isolation, providing conditions for rapid genetic drift and novel selection pressures. Here, stepwise discriminant function analysis and fluctuating asymmetry are used to examine variation in morphology within and among non fragmented and recently fragmented populations of two species of gecko,Oedura reticulata andGehyra variegata. High reclassification error rates using discriminant function analysis, indicate that fragmentation has had no detectable effect on morphological differentiation among populations of either species. In contrast, remnant populations of both species exhibit higher mean levels of fluctuating asymmetry than do populations in undisturbed habitat. ForOedura reticulata, levels of fluctuating asymmetry are negatively correlated with the log of adult population size. These results suggest that the changes following habitat clearance have been severe enough to cause increased developmental instability in populations of both species but not detectable morphological divergence. Given the high rate of extirpation of gecko populations in the study region and the extreme vulnerability of the remaining populations, it is unlikely that species formation will be significant in maintaining reptile diversity in that region.     

Effects of Short-Term Climatic Variations on Fluctuating Asymmetry Levels in Chironomus Riparius Larvae at a Polluted Site

We examined fluctuating asymmetry (FA) levels in fourth-instar larvae of Chironomus riparius(Diptera, Chironomidae) collected monthly from a polluted site in Galicia (NW Spain) where pollutant inputs are known to be roughly constant throughout the year. The site was selected because, despite this constancy in pollutant inputs, deformities in fourth-instar larvae were previously found to be more frequent and severe during cold periods and less frequent and severe during warm periods of the year, in accordance with the ‘time-of-exposure’ hypothesis. This hypothesis predicts that short-term climatic variations occurring throughout the year influence the frequency and severity of larval morphological alterations, by means of the control they exert on developmental time and, as a consequence, on the time larvae remain exposed to pollutants. We investigated whether FA levels in larvae were likewise in accordance with this hypothesis, but, contrary to our expectations, no significant differences in FA levels were detected either among months or among seasons, suggesting that FA is not influenced by normal climatic variations. However, climatic influences may be masked, and the observed constancy in FA levels over the sampling period may be a consequence of the action of a mixture of stressors which compensate each other.     

Fluctuating asymmetry of morphometric characters in house mice: the effects of age, sex, and phenotypical extremeness in a randombred population

Fluctuating asymmetry (FA) was calculated for nine paired morphometric characters in a randombred population of house mice in order to assess the effects of age, sex, and phenotypical extremeness. FA did not significantly vary between sexes for any of the characters, and age proved to be significant only for innominate length. Additionally, FA values in high extreme individuals and low extreme individuals were compared to those for intermediate individuals to discover whether extreme individuals showed increased fluctuating asymmetry (decreased developmental stability) due to increased levels of homozygosity. Differences in fluctuating asymmetry magnitudes were found between the groups, although the extreme individuals did not consistently show increased fluctuating asymmetry and FA differences also showed no significant association with the level of heritability of each character. Potential reasons for these findings are discussed.     

Developmental stability in flowers of Clarkia tembloriensis (Onagraceae)

Developmental instability of floral traits is examined in four populations of Clarkia tembloriensis (Onagraceae) with different natural outcrossing rates. Developmental instability is estimated using fluctuating asymmetry (FA) and within plant variance. The results are coupled with those from a previous study of leaf traits. In the first experiment, flowers were collected from the same growth chamber-grown plants that had been previously used to estimate leaf developmental stability in two C. tembloriensis populations. These populations differed in FA for only one floral trait, long filament length. After adjusting for organ size differences, we found floral FA values were about half those of leaves. These are the first quantitative data indicating that flowers are more developmentally stable than leaves. In a second experiment, greenhouse grown plants from two other C. tembloriensis populations (one highly outcrossing and one predominantly self-pollinating) did not differ significantly in floral FA or in within-plant variance of floral traits, though earlier studies of the same populations revealed significant differences in FA of leaf traits. In both experiments, FA values of different floral traits were uncorrelated. We attribute the lack of significant differences in floral stability between populations to the greater canalization of floral organs and to the magnification of measurement error that occurs when calculating FA. We also found that the shorter styles of selfers are the greatest difference in flower form between predominantly self-pollinating and predominantly outcrossing populations of C. tembloriensis.     

Discovery of charophyte flora across the Cretaceous–Paleocene transition in the Jiaolai Basin

Charophyte assemblages from the Cretaceous/Paleogene (K/Pg) boundary transition in the JZK-2 borehole of the Jiaolai Basin (eastern China) were studied. The charophyte flora includes Tolypella grambastii, Peckichara praecursoria, Microchara cristata, Microchara prolixa, Chara changzhouensis, Lamprothamnium ellipticum, Nodosochara (Turbochara) specialis, Lychnothamnus aff. vectensis, and Lychnothamnus lanpingensis n. comb. The discovery of the ostracod species Porpocypris sphaeroidalis Guan in the upper section of the JZK-2 borehole strongly indicates the arrival of the Paleocene. Three floras of the latest Cretaceous to the early Paleocene were compared among the Jiaolai, Pingyi, and Songliao basins. The Pingyi Basin is special because it is the only carbonate palaeolake that occurred throughout the K/Pg transition in China. It is characterized by the appearance of the Cretaceous brackish water element, Feistiella anluensis (Wang), and is dominated by the Paleocene species, Peckichara varians Grambast. The Songliao and Jiaolai floras grow in clastic lakes; the Jiaolai Basin is thought to correspond to an altitude lake, which was formed in the coastal mountains with high palaeoelevation (≥ 2.0 km), while the Songliao Basin is presumed to have been formed in a low elevation site according to previous studies. This difference in altitude explains why the Songliao Basin is more species-rich than the Jiaolai Basin.