Kerguelen Plateau and the Late Cretaceous southern-continent bioconnection hypothesis: tales from a topographical ocean

Aim  To evaluate rigorously an influential palaeobiogeographical hypothesis which states that in the Late Cretaceous (until c. 80 Ma) the Kerguelen Plateau provided a terrestrial causeway between East Antarctica and India that, in turn, formed part of a longer overland route between South America and Madagascar.
Location  Southern Ocean, Indian Ocean, East Antarctica, India and Madagascar.
Methods  Palaeogeographical modelling drawing on geological and geophysical data, bathymetric charts and plate tectonic reconstructions.
Results  During the Late Cretaceous, only small portions of the present-day Kerguelen Plateau were sub-aerial. Additionally, the plateau's north-north-west and south-south-east ends did not directly abut India and Antarctica, but instead were separated by large gaps. Thus, the notion that the two continents were then linked by a land route running the entire length of the edifice is almost certainly incorrect.
Main conclusions  The currently available physical evidence indicates that the Late Cretaceous southern-continent connection hypothesis, which is based exclusively on biological data, is untenable. Assuming the fossil and/or extant biological records of Madagascar–India are closely related to those of South America, alternative palaeogeographical scenarios need to be explored to explain this conundrum. Overwater dispersal and/or an alternative passage involving a more direct route via Africa (with crossings of the Mozambique Channel and a then appreciably narrower Central Atlantic) should be considered.     

Diversity patterns amongst herbivorous dinosaurs and plants during the Cretaceous: implications for hypotheses of dinosaur/angiosperm co‐evolution

Abstract Palaeobiologists frequently attempt to identify examples of co‐evolutionary interactions over extended geological timescales. These hypotheses are often intuitively appealing, as co‐evolution is so prevalent in extant ecosystems, and are easy to formulate; however, they are much more difficult to test than their modern analogues. Among the more intriguing deep time co‐evolutionary scenarios are those that relate changes in Cretaceous dinosaur faunas to the primary radiation of flowering plants. Demonstration of temporal congruence between the diversifications of co‐evolving groups is necessary to establish whether co‐evolution could have occurred in such cases, but is insufficient to prove whether it actually did take place. Diversity patterns do, however, provide a means for falsifying such hypotheses. We have compiled a new database of Cretaceous dinosaur and plant distributions from information in the primary literature. This is used as the basis for plotting taxonomic diversity and occurrence curves for herbivorous dinosaurs (Sauropodomorpha, Stegosauria, Ankylosauria, Ornithopoda, Ceratopsia, Pachycephalosauria and herbivorous theropods) and major groups of plants (angiosperms, Bennettitales, cycads, cycadophytes, conifers, Filicales and Ginkgoales) that co‐occur in dinosaur‐bearing formations. Pairwise statistical comparisons were made between various floral and faunal groups to test for any significant similarities in the shapes of their diversity curves through time. We show that, with one possible exception, diversity patterns for major groups of herbivorous dinosaurs are not positively correlated with angiosperm diversity. In other words, at the level of major clades, there is no support for any diffuse co‐evolutionary relationship between herbivorous dinosaurs and flowering plants. The diversification of Late Cretaceous pachycephalosaurs (excluding the problematic taxon Stenopelix) shows a positive correlation, but this might be spuriously related to poor sampling in the Turonian–Santonian interval. Stegosauria shows a significant negative correlation with flowering plants and a significant positive correlation with the nonflowering cycadophytes (cycads, Bennettitales). This interesting pattern is worthy of further investigation, and it reflects the decline of both stegosaurs and cycadophytes during the Early Cretaceous.     

The capsule: an organic skeletal structure in the Late Cretaceous belemnite Gonioteuthis from north‐west Germany

Abstract: An unusual, bilaterally symmetrical black structure that embraces the protoconch and the phragmocone and is overlain by a rostrum has been studied in the Santonian–early Campanian (Late Cretaceous) belemnite genus Gonioteuthis from Braunschweig, north‐west Germany. The structure is here named the capsule. Energy dispersed spectrometry analyses of the capsule show a co‐occurrence of sulphur with zinc, barium, iron, lead and titanium, suggesting their chemical association. The capsule was originally made of organic material that was diagenetically transformed into sulphur‐containing matter. The material of the capsule differs from the chitin of the connecting rings in the same specimens. The capsule has a complex morphology: (1) ventral and dorsal wing‐like projections that are repeated in a breviconic shape of the alveolus, (2) an aperture with lateral lobes and ventral and dorsal sinuses copied by growth lines and (3) a ventral ridge that fits with the position of the fissure in the rostrum. The alveolus in the most anterior part of the rostrum is crater‐like. It is lined with thin, pyritized, laminated material, which appears to be the outermost portion of the capsule attached to the inner surface of the rostrum. A flare along the periphery of the alveolus marks a region where the rostrum was not yet formed, suggesting that the capsule extended beyond the rostrum. Modification of the skeleton in Gonioteuthis comprises a set of supposedly interrelated changes, such as innovation of the organic capsule, partial elimination of the calcareous rostrum and a diminishing of the pro‐ostracum, resulting in the appearance of a new type of pro‐ostracum that became narrower and shorter and lost the spatula‐like shape and gently curved growth lines of a median field that are typical for the majority of Jurassic and Cretaceous belemnites. The partial replacement of a calcareous rostrum with an organic capsule in belemnitellids may have been an adaptive reaction to an unfavourable environmental condition, perhaps related to difficulties in calcium carbonate secretion during the Late Cretaceous that forced animals to reduce carbonate production and to secret an organic capsule around the protoconch and the phragmocone.     

Squatiniformes (Chondrichthyes,Neoselachii) from the Late Cretaceous of southern England and northern France with redescription of the holotype of Squatina cranei Woodward, 1888

Abstract: Bulk sampling of phosphate‐rich horizons within the Late Cretaceous of the Anglo‐Paris Basin yielded numerous teeth of members of the Squatiniformes. Along with isolated tooth remains, two museum specimens comprising partial articulated encoskeletal remains including the holotype of the species Squatina cranei Woodward, 1888a are described, and a new subgenus Cretascyllium is proposed for species of the genus Squatina with high degree of heterodonty and triangular anterior teeth. The species Squatina (Cretascyllium) cranei comb. nov. and Squatina (Cretascyllium) hassei comb. nov. are referred to this subgenus. The genus Parasquatina Herman, 1982 previously erected on a single tooth is valid, and two new species P. justinensis sp. nov. and P. jarvisi sp. nov. are described along with a third taxon Parasquatina sp. An enigmatic tooth referred to ?Neoselachii incertae sedis is also reported. The palaeoecology of these taxa is discussed.     

A preliminary phylogeny of the Pterasteridae (Echinodermata,Asteroidea) and the first fossil record: Late Cretaceous of Germany and Belgium

The Pterasteridae comprises a diversified group of extant largely deep-sea starfishes. Generic diagnoses have been based classically on soft tissue characters and skeletal architecture. A preliminary phylogeny of sixteen extant species is here worked out by cladistic analysis. The resulting tree suggests monophyly of extant genera and the validity of dissociated plates for identification of genera. Fossil remains of Pterasteridae are here described for the first time. By comparison with extant species, all the skeletal remains from the lower Upper Campanian of Belgium and from the lower Maastrichtian of Germany are tentatively assigned to the genusPteraster. The fossil record of starfishes is poor, but the present Late Cretaceous pterasterids provide one more piece of evidence of the high diversity of starfishes during the Mesozoic. Known Late Cretaceous and Paleogene fossils are broadly similar, which suggests the end-Cretaceous extinction event did not cause major turnover in asteroid faunal composition. As suggested for other starfish groups, both the fossil record of deep-sea Pterasteridae in shelf settings and tree topology imply an onshore-offshore evolutionary trend.      

Biotic and environmental dynamics through the Late Jurassic–Early Cretaceous transition: evidence for protracted faunal and ecological turnover

The Late Jurassic to Early Cretaceous interval represents a time of environmental upheaval and cataclysmic events, combined with disruptions to terrestrial and marine ecosystems. Historically, the Jurassic/Cretaceous (J/K) boundary was classified as one of eight mass extinctions. However, more recent research has largely overturned this view, revealing a much more complex pattern of biotic and abiotic dynamics than has previously been appreciated. Here, we present a synthesis of our current knowledge of Late Jurassic–Early Cretaceous events, focusing particularly on events closest to the J/K boundary. We find evidence for a combination of short‐term catastrophic events, large‐scale tectonic processes and environmental perturbations, and major clade interactions that led to a seemingly dramatic faunal and ecological turnover in both the marine and terrestrial realms. This is coupled with a great reduction in global biodiversity which might in part be explained by poor sampling. Very few groups appear to have been entirely resilient to this J/K boundary ‘event’, which hints at a ‘cascade model’ of ecosystem changes driving faunal dynamics. Within terrestrial ecosystems, larger, more‐specialised organisms, such as saurischian dinosaurs, appear to have suffered the most. Medium‐sized tetanuran theropods declined, and were replaced by larger‐bodied groups, and basal eusauropods were replaced by neosauropod faunas. The ascent of paravian theropods is emphasised by escalated competition with contemporary pterosaur groups, culminating in the explosive radiation of birds, although the timing of this is obfuscated by biases in sampling. Smaller, more ecologically diverse terrestrial non‐archosaurs, such as lissamphibians and mammaliaforms, were comparatively resilient to extinctions, instead documenting the origination of many extant groups around the J/K boundary. In the marine realm, extinctions were focused on low‐latitude, shallow marine shelf‐dwelling faunas, corresponding to a significant eustatic sea‐level fall in the latest Jurassic. More mobile and ecologically plastic marine groups, such as ichthyosaurs, survived the boundary relatively unscathed. High rates of extinction and turnover in other macropredaceous marine groups, including plesiosaurs, are accompanied by the origin of most major lineages of extant sharks. Groups which occupied both marine and terrestrial ecosystems, including crocodylomorphs, document a selective extinction in shallow marine forms, whereas turtles appear to have diversified. These patterns suggest that different extinction selectivity and ecological processes were operating between marine and terrestrial ecosystems, which were ultimately important in determining the fates of many key groups, as well as the origins of many major extant lineages. We identify a series of potential abiotic candidates for driving these patterns, including multiple bolide impacts, several episodes of flood basalt eruptions, dramatic climate change, and major disruptions to oceanic systems. The J/K transition therefore, although not a mass extinction, represents an important transitional period in the co‐evolutionary history of life on Earth.     

Vicariance or long‐distance dispersal: historical biogeography of the pantropical subfamily Chrysophylloideae (Sapotaceae)

Aim Continental disjunctions in pantropical taxa have been explained by vicariance or long‐distance dispersal. The relative importance of these explanations in shaping current distributions may vary, depending on historical backgrounds or biological characteristics of particular taxa. We aimed to determine the geographical origin of the pantropical subfamily Chrysophylloideae (Sapotaceae) and the roles vicariance and dispersal have played in shaping its modern distribution. Location Tropical areas of Africa, Australasia and South America. Methods We utilized a recently published, comprehensive data set including 66 species and nine molecular markers. Bayesian phylogenetic trees were generated and dated using five fossils and the penalized likelihood approach. Distributional ranges of nodes were estimated using maximum likelihood and parsimony analyses. In both biogeographical and molecular dating analyses, phylogenetic and branch length uncertainty was taken into account by averaging the results over 2000 trees extracted from the Bayesian stationary sample. Results Our results indicate that the earliest diversification of Chrysophylloideae was in the Campanian of Africa c. 73–83 Ma. A narrow time interval for colonization from Africa to the Neotropics (one to three dispersals) and Australasia (a single migration) indicates a relatively rapid radiation of this subfamily in the latest Cretaceous to the earliest Palaeocene (c. 62–72 Ma). A single dispersal event from the Neotropics back to Africa during the Neogene was inferred. Long‐distance dispersal between Australia and New Caledonia occurred at least four times, and between Africa and Madagascar on multiple occasions. Main conclusions Long‐distance dispersal has been the dominant mechanism for range expansion in the subfamily Chrysophylloideae. Vicariance could explain South American–Australian disjunction via Antarctica, but not the exchanges between Africa and South America and between New Caledonia and Australia, or the presence of the subfamily in Madagascar. We find low support for the hypothesis that the North Atlantic land bridge facilitated range expansions at the Palaeocene/Eocene boundary.     

Largest reported groups for the Indo‐Pacific bottlenose dolphin (Tursiops aduncus) found in Algoa Bay,South Africa: Trends and potential drivers

This study investigates how group size of Indo‐Pacific bottlenose dolphins (Tursiops aduncus) changes temporally, spatially, and/or with predominant behavior at two discreet sites along the Eastern Cape coastline of South Africa: Algoa Bay and the Wild Coast. The mean group size of bottlenose dolphins was large with an average of 52 animals. Significantly larger groups were observed in Algoa Bay ( = 60, range = 1–600) than off the Wild Coast ( = 32.9, range = 1–250). In Algoa Bay, the mean group size increased significantly over the study period, from an average 18 animals in 2008 to 76 animals in 2016. Additionally, the largest average and maximum group sizes ever reported both in South Africa and worldwide, were recorded in Algoa Bay (maximum group size = 600). Neither season nor behavior had a significant effect on mean group size at both sites. Similarly environmental variables such as the depth and substrate type also had no influence on group size. It remains unclear which ecological drivers, such as predation risk and food availability, are leading to the large groups observed in this area, and further research on abundance and distribution of both predators and prey is necessary.     

New remains of <Emphasis Type="Italic">Hungarosaurus tormai</Emphasis> (Ankylosauria,Dinosauria) from the Upper Cretaceous of Hungary: skeletal reconstruction and body mass estimation

Hungarosaurus tormai is a medium-sized nodosaurid ankylosaur that was described on the basis of four partial skeletons from the Santonian (Upper Cretaceous) of Hungary. In this paper, a new fifth skeleton and several isolated remains are described which greatly improve our knowledge of this primitive nodosaurid ankylosaur. Isolated cranial remains referred to juvenile individuals provide new information on the development of cranial ornamentation in nodosaurid ankylosaurs. Apart from both preserved mandibles with in situ dentition, the fifth partial skeleton contains several previously unknown limb elements (humerus, ulnae, radius) that indicate unusual limb proportions for Hungarosaurus compared with other ankylosaurs. On the basis of the five partial skeletons and the isolated remains, a skeletal and dermal armor reconstruction is attempted. Body mass calculations using three different methods yield an estimate of 650 kg for H. tormai.      

Out of Australia and back again: the world‐wide historical biogeography of non‐pollinating fig wasps (Hymenoptera: Sycophaginae)

Aim Figs (Ficus, Moraceae) are exploited by rich communities of often host‐specific phytophagous wasps. Among them, gall‐inducing Sycophaginae (Hymenoptera, Chalcidoidea) may share a common history with Ficus and their mutualistic pollinators (Agaonidae). We investigate here, for the first time, the phylogeny and biogeographical history of Sycophaginae and compare the timing of radiation and dispersion of major clades with available data on Ficus and fig pollinators. Reconstructing the history of their host colonization and association over space and time is central to understanding how fig wasp communities were assembled. Location World‐wide. Methods Maximum likelihood and Bayesian analyses were conducted on 4267 bp of mitochondrial and nuclear DNA to produce a phylogeny of all genera of Sycophaginae. Two relaxed clock methods with or without rate autocorrelation were used for date estimation. Analyses of ancestral area were also conducted to investigate the geographical origin of the Sycophaginae. Results The phylogeny is well resolved and supported. Our data suggest a post‐Gondwanan origin for the Sycophaginae (50–40 Ma) and two independent out‐of‐Australia dispersal events to continental Asia. Given palaeoclimatic and palaeogeographic records, the following scenario appears the most likely. The ancestor of Idarnes+Apocryptophagus migrated to Greater India through the Ninetyeast Ridge (40–30 Ma). The ancestor of Anidarnes+Conidarnes dispersed later via Sundaland (25–20 Ma). Idarnes and Anidarnes subsequently reached the New World via the North Atlantic land bridges during the Late Oligocene Warming Event. Apocryptophagus reached Africa c. 20 Ma via the Arabic corridors and returned to Australasia following the expansion of Sundaland tropical forests (20–10 Ma). Main conclusions Sycophaginae probably invaded the fig microcosm in Australia c. 50–40 Ma after the origin of their host plant. Once associated with figs, they dispersed out of Australia and radiated together with their host fig and associated pollinator through the tropics. We recorded a good coincidence of timing between dispersal events of Sycophaginae and continental connections. Furthermore, fruit pigeons that disperse figs probably spread out of Australasia through the Indian Ocean via the Ninetyeast Ridge c. 38 Ma. Therefore, our study highlights the potential for combining molecular phylogenetics with multiple methods of dating of interacting groups to reconstruct the historical biogeography of plant–herbivore associations.     

Provannid and provannid‐like gastropods from the Late Cretaceous cold seeps of Hokkaido (Japan) and the fossil record of the Provannidae (Gastropoda: Abyssochrysoidea)

A fauna of provannid and provannid‐like shells is described from Upper Cretaceous seep carbonates in Hokkaido, Japan. We describe two new provannid species, Provanna tappuensis sp. nov. and Desbruyeresia kanajirisawensis sp. nov. , with preserved protoconchs of unquestionable provannid type with decollate apex. This material confirms the occurrence of Provannidae as early as the Middle Cenomanian. We also describe Hokkaidoconcha gen. nov. and a new family Hokkaidoconchidae fam. nov. , with two named species, H. hikidai sp. nov. and H. tanabei sp. nov . Hokkaidoconchidae are possibly related to the Provannidae, judging from a similar, but not decollate larval shell, although the juvenile teleoconch whorls differ in being of a general cerithimorph appearance and the details of the aperture are unknown. Furthermore, we review the published fossil record of Provannidae and Abyssochrysidae, and we consider that in those older than the Eocene, there is no evidence preserved that unequivocally supports a position there. The Jurassic Acanthostrophia acanthica from Italy seems to be the oldest known record of Abyssochrysidae, and the most reliable occurrence of the family, older than from the Miocene. Other fossil, pre‐Miocene species that have been classified in the Abyssochryssidae are provisionally referred to Hokkaidoconchidae. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 421–436.     

Analysis of Late Jurassic to Early Cretaceous algal debris-facies of the Plassen carbonate platform in the Northern Calcareous Alps (Germany,Austria) and in the Kurbnesh area of the Mirdita zone (Albania): a tool to reconstruct tectonics and palaeogeography of eroded platforms

A characteristic microfacies of the Late Jurassic to Early Cretaceous allodapic Barmstein Limestone of the Northern Calcareous Alps are clasts of wackestones with numerous fragments of calcareous algae (“algal debris-facies”). According to dasycladale palaeocoenoses, several subtypes comprising different associations can be distinguished. One association is characterized by the debris of an unknown large dasycladalean alga reported as dasycladalean alga indet. sp. 1 from different localities in the Northern Calcareous Alps, typically forming a monospecific assemblage. Another microfacies type contains star-like calcitic bodies tentatively referred to the morphospecies Coptocampylodon pantici Ljubović-Obradović and Radoičić, originally described as being from the Turonian of NW-Serbia. Other Coptocampylodon-like bodies represent the calcified tufts of the laterals of Selliporella neocomiensis (Radoičić). The occurrence of Coptocampylodon pantici-like microfossils in the Late Tithonian to Early Berriasian, shows that obviously different species of dasycladaleans display identical to similar shaped tufts of laterals in transverse sections when becoming fragmented. Coptocampylodon pantici Ljubović-Obradović and Radoičić was observed only from different occurrences of Barmstein Limestone, but not from the autochthonous platform carbonates of the Plassen carbonate platform. The Coptocampylodon algal debris-facies is also reported from the Late Jurassic of Albania, Mirdita zone. Occurrences of different types of algal debris-facies in components of mass-flow deposits can be used as a tool to reconstruct eroded carbonate platforms and tectonics, as demonstrated in the Northern Calcareous Alps and the Albanides. Finally, the general occurrences of algal debris-facies in both settings—intra-Tethyan mostly isolated platforms (Alps, Albanides) vs. extended epeiric platforms (Middle East)—are compared and discussed.     

Limited connectivity and a phylogeographic break characterize populations of the pink anemonefish,Amphiprion perideraion,in the Indo‐Malay Archipelago: inferences from a mitochondrial and microsatellite loci

To enhance the understanding of larval dispersal in marine organisms, species with a sedentary adult stage and a pelagic larval phase of known duration constitute ideal candidates, because inferences can be made about the role of larval dispersal in population connectivity. Members of the immensely diverse marine fauna of the Indo‐Malay Archipelago are of particular importance in this respect, as biodiversity conservation is becoming a large concern in this region. In this study, the genetic population structure of the pink anemonefish, Amphiprion perideraion, is analyzed by applying 10 microsatellite loci as well as sequences of the mitochondrial control region to also allow for a direct comparison of marker‐derived results. Both marker systems detected a strong overall genetic structure (Φ_ST = 0.096, P < 0.0001; mean D_est = 0.17; F_ST = 0.015, P < 0.0001) and best supported regional groupings (Φ_CT = 0.199 P < 0.0001; F_CT = 0.018, P < 0.001) that suggested a differentiation of the Java Sea population from the rest of the archipelago. Differentiation of a New Guinea group was confirmed by both markers, but disagreed over the affinity of populations from west New Guinea. Mitochondrial data suggest higher connectivity among populations with fewer signals of regional substructure than microsatellite data. Considering the homogenizing effect of only a few migrants per generation on genetic differentiation between populations, marker‐specific results have important implications for conservation efforts concerning this and similar species.     

The Balkans and the colonization of Europe: the post‐glacial range expansion of the wild boar,Sus scrofa

Aim We focus on the biogeographical role of the Balkan Peninsula as a glacial refugium and source of northward post‐glacial dispersal for many European taxa. Specifically, we analysed the genetic structure and variation of wild boar (Sus scrofa) samples primarily from Greece, a region that has repeatedly served as a glacial refugium within the Balkan Peninsula. Location Continental Greece, the Aegean island of Samos and Bulgaria. Methods We analysed wild boar samples from 18 localities. Samples from common domestic breeds were also examined to take into account interactions between wild and domesticated animals. Phylogenetic analyses were carried out on a 637‐bp fragment of the mitochondrial DNA control region in 200 wild boar and 27 domestic pigs. The sequences were also compared with 791 Eurasian wild boar and domestic pig D‐loop sequences obtained from GenBank. Results Ninety‐four haplotypes were identified in the European wild boar data set, of which 68 were found in the Balkan samples and assigned to two previously described clades: the E1 European and Near Eastern clades. All of the continental samples clustered in the E1 clade and the samples from Samos fell into the Near Eastern clade, consistent with the island’s proximity to Asia Minor. Intriguingly, 62 novel haplotypes were identified and are found exclusively in the Balkans. Only six haplotypes were shared between wild boar and domestic pigs. Main conclusions Our data reveal numerous novel and geographically restricted haplotypes in wild boar populations, suggesting the presence of separate refugia in the Balkans. Our analyses support the hypothesis of a post‐glacial wild boar expansion consistent with the leading edge model, north and west from modern day Greece, and suggest little maternal introgression of Near Eastern and domestic haplotypes into wild Balkan populations.     

Shift down,look up: A test of the non‐linearity and fear hypothesis in a non‐vocal skink

The non‐linearity and fear hypothesis predicts that certain non‐linear sounds are one way to evoke antipredator responses in both birds and mammals. This hypothesis, however, has not been studied in non‐vocal species or in reptiles. Such a study would be important because if non‐linear sounds are evocative even in a species that does not produce sounds, then there may be generally salient cues of risk in these sounds. We asked whether non‐vocal lizards, white‐bellied copper‐striped skinks (Emoia cyanura), respond to experimentally broadcast non‐linearities. This species is ideal to ask the question in because prior research has shown that they respond to predator sounds and alarm calls of other species even though they are not vocal. We conducted playback experiments with three computer‐generated simulated non‐linearities to assess whether or not skinks increased antipredator behavior after hearing them. We controlled for novelty by broadcasting a 3‐kHz, 500‐ms pure tone and tropical kingbird (Tyrannus melancholicus) song. Our treatments consisted of a 3‐kHz, 400‐ms pure tone followed by a frequency shift up to 5‐kHz for 100‐ms, a 3‐kHz, 400‐ms pure tone to frequency shift down to 1‐kHz for 100‐ms, and a pure tone followed by 100‐ms of white noise. Following a total of 222 playbacks, we categorized responses into looking, locomotion, and high locomotion, focusing on how skinks changed their rates of time allocation from baseline. We examined 95% confidence intervals to identify whether skinks responded to playbacks and fitted general linear models followed by pairwise comparisons to ask whether skinks discriminated between broadcast stimuli. We found that skinks were especially responsive to frequency downshifts: They significantly increased looking and locomotion, consistent with our predictions based on the non‐linearity and fear hypothesis. Surprisingly, they decreased rates of looking behavior after hearing frequency upshifts, possibly suggesting an increase in relaxed behavior. While skinks responded to noise by increasing their rate of locomotion, this response was not significantly different from controls. We conclude that skinks increase antipredator behavior after hearing downshifts more than any other type of non‐linearity. This provides some support for the non‐linearity and fear hypothesis; even non‐vocal species may respond fearfully to specific types of non‐linear sounds.     

Idiosyncratic responses to climate‐driven forest fragmentation and marine incursions in reed frogs from Central Africa and the Gulf of Guinea Islands

Organismal traits interact with environmental variation to mediate how species respond to shared landscapes. Thus, differences in traits related to dispersal ability or physiological tolerance may result in phylogeographic discordance among co‐distributed taxa, even when they are responding to common barriers. We quantified climatic suitability and stability, and phylogeographic divergence within three reed frog species complexes across the Guineo‐Congolian forests and Gulf of Guinea archipelago of Central Africa to investigate how they responded to a shared climatic and geological history. Our species‐specific estimates of climatic suitability through time are consistent with temporal and spatial heterogeneity in diversification among the species complexes, indicating that differences in ecological breadth may partly explain these idiosyncratic patterns. Likewise, we demonstrated that fluctuating sea levels periodically exposed a land bridge connecting Bioko Island with the mainland Guineo‐Congolian forest and that habitats across the exposed land bridge likely enabled dispersal in some species, but not in others. We did not find evidence that rivers are biogeographic barriers across any of the species complexes. Despite marked differences in the geographic extent of stable climates and temporal estimates of divergence among the species complexes, we recovered a shared pattern of intermittent climatic suitability with recent population connectivity and demographic expansion across the Congo Basin. This pattern supports the hypothesis that genetic exchange across the Congo Basin during humid periods, followed by vicariance during arid periods, has shaped regional diversity. Finally, we identified many distinct lineages among our focal taxa, some of which may reflect incipient or unrecognized species.     

Study of the interactions between a proline‐rich protein and a flavan‐3‐ol by NMR: Residual structures in the natively unfolded protein provides anchorage points for the ligands

Astringency is one of the major organoleptic properties of food and beverages that are made from plants, such as tea, chocolate, beer, or red wine. This sensation is thought to be due to interactions between tannins and salivary proline‐rich proteins, which are natively unfolded proteins. A human salivary proline‐rich protein, namely IB‐5, was produced by the recombinant method. Its interactions with a model tannin, epigallocatechin gallate (EGCG), the major flavan‐3‐ol in green tea, were studied here. Circular dichroism experiments showed that IB‐5 presents residual structures (PPII helices) when the ionic strength is close to that in saliva. In the presence of these residual structures, IB‐5 undergoes an increase in structural content upon binding to EGCG. NMR data corroborated the presence of preformed structural elements within the protein prior to binding and a partial assignment was proposed, showing partial structuration. TOCSY experiments showed that amino acids that are involved in PPII helices are more likely to interact with EGCG than those in random coil regions, as if they were anchorage points for the ligand. The signal from IB‐5 in the DOSY NMR spectrum revealed an increase in polydispersity upon addition of EGCG while the mean hydrodynamic radius remained unchanged. This strongly suggests the formation of IB‐5/EGCG aggregates. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 745–756, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Simulation of greenhouse gases following land‐use change to bioenergy crops using the ECOSSE model: a comparison between site measurements and model predictions

This article evaluates the suitability of the ECOSSE model to estimate soil greenhouse gas (GHG) fluxes from short rotation coppice willow (SRC‐Willow), short rotation forestry (SRF‐Scots Pine) and Miscanthus after land‐use change from conventional systems (grassland and arable). We simulate heterotrophic respiration (R_h), nitrous oxide (N₂O) and methane (CH₄) fluxes at four paired sites in the UK and compare them to estimates of R_h derived from the ecosystem respiration estimated from eddy covariance (EC) and R_h estimated from chamber (IRGA) measurements, as well as direct measurements of N₂O and CH₄ fluxes. Significant association between modelled and EC‐derived R_h was found under Miscanthus, with correlation coefficient (r) ranging between 0.54 and 0.70. Association between IRGA‐derived R_h and modelled outputs was statistically significant at the Aberystwyth site (r = 0.64), but not significant at the Lincolnshire site (r = 0.29). At all SRC‐Willow sites, significant association was found between modelled and measurement‐derived R_h (0.44 ≤ r ≤ 0.77); significant error was found only for the EC‐derived R_h at the Lincolnshire site. Significant association and no significant error were also found for SRF‐Scots Pine and perennial grass. For the arable fields, the modelled CO₂ correlated well just with the IRGA‐derived R_h at one site (r = 0.75). No bias in the model was found at any site, regardless of the measurement type used for the model evaluation. Across all land uses, fluxes of CH₄ and N₂O were shown to represent a small proportion of the total GHG balance; these fluxes have been modelled adequately on a monthly time‐step. This study provides confidence in using ECOSSE for predicting the impacts of future land use on GHG balance, at site level as well as at national level.