Spatial variation in population density across the geographical range in helminth parasites of yellow perch Perca flavescens

The abundance of a species is not constant across its geographical range; it has often been assumed to decrease from the centre of a species’ range toward its margins. The central assumption of this “favourable centre” model is tested for the first time with parasites, using different species of helminth parasites exploiting fish as definitive hosts. Data on prevalence (percentage of hosts that are infected) and abundance (mean no. parasites per host) were compiled for 8 helminth species occurring in 23 populations of yellow perch Perca flavescens, from continental North America. For each parasite species, correlations were computed between latitude and both local prevalence and abundance values. In addition, the relationships between the relative prevalence or abundance in one locality and the distance between that locality and the one where the maximum value was reported, were assessed separately for each species to determine whether abundance tends to decrease away from the presumed centre of the range, where it peaks. For both the cestode Proteocephalus pearsei and the acanthocephalan Leptorhynchoides thecatus, there was a positive relationship between prevalence or abundance and the latitude of the sampled population. There was also a significant negative relationship between relative prevalence and the distance from the locality showing the maximum value in P. pearsei, but no such pattern was observed for the other 7 parasite species. Since this single significant decrease in prevalence with increasing distance from the peak value may be confounded by a latitudinal gradient, it appears that the distribution of abundance in parasites of perch does not follow the favourable centre model. This means that the environmental variables affecting the density of parasites (host availability, abiotic conditions) do not show pronounced spatial autocorrelation, with nearby sites not necessarily providing more similar conditions for the growth of parasite populations than distant sites.     

Enteric helminths of perch (Perca fluviatilis L.) and yellow perch (Perca flavescens Mitchill): stochastic or predictable assemblages?

Component communities of perch (Perca fluviatilis L) in Eurasia and the North American yellow perch (Perca flavescens Mitchill) were examined to determine the nature of their parasite communities. The scale of this investigation is continental and includes data collected across the distribution of each host species. Data were compiled from the literature and from 5 sample sites in North America. Four parasite species were found to occur frequently in the helminth component communities of P. flavescens. The cestodes Bothriocephalus cuspidatus and Proteocephalus pearsei, the digenean Crepidostomum cooperi, and the nematode Dichelyne cotylophora comprised a suite of species of which some or all occurred in most samples. Similarly, a group of 4 predictable parasite species was identified for P. fluviatilis in Eurasia, the digenean Bunodera luciopercae, the nematode Camallanus lacustris, the cestode Proteocephalus percae, and the acanthocephalan Acanthocephalus lucii. Specificity was not a requirement for predictability. Despite geographical isolation for millions of years, and different fish species interactions within and between continents, the predictability of these parasite assemblages indicates they are shaped by a biology, especially feeding patterns, common to both perch species. This is evidence that parasite assemblages comprised of nonhost-specific parasites in freshwater fishes are not merely stochastic assemblages but have key components that are predictable at this broad continental scale.     

New records of endoparasitic helminths in alien invasive fishes from the Carpathian region

Six non-native invasive fish species from the Slovak part of the Tisa River basin, namely Carassius gibelio, Pseudorasbora parva, Ameiurus melas, A. nebulosus, Lepomis gibbosus, Perccottus glenii, and three gobiid species from the Danube River, namely Neogobius melanostomus, N. fluviatilis and N. kessleri, were investigated for endohelminth parasites. The expanding Asian cestode Nippotaenia mogurndae (syn. Amurotaenia perccotti) (Nippotaeniidea) has been introduced to Europe with its invasive host P. glenii. Pumpkinseed, Lepomis gibbosus, is a new definitive host of Proteocephalus percae and it is reported as the second intermediate host of the bothriocephalidean cestode Triaenophorus nodulosus in Slovakia.     

Genetically distinct colour morphs of European perch Perca fluviatilis in Lake Constance differ in susceptibility to macroparasites

The unusual yellow‐finned morph of European perch Perca fluviatilis found in Lake Constance suffers more severely from macroparasite infections, including the tapeworm Triaenophorus nodulosus and the gill worm Ancyrocephalus percae, than conspecifics elsewhere. Microsatellite analysis of yellow‐finned P. fluviatilis and red‐finned variant recently discovered in Lake Constance revealed significant genetic differentiation. Red‐finned P. fluviatilis and fish with mixed fin colour, suggested backcrosses between red and yellow‐finned colour morphs, exhibit better resilience to parasite infection, suggesting that the inability of the yellow‐finned morph to reject macroparasites may have a genetic basis.     

Parasite spillover: indirect effects of invasive Burmese pythons

Identification of the origin of parasites of nonindigenous species (NIS) can be complex. NIS may introduce parasites from their native range and acquire parasites from within their invaded range. Determination of whether parasites are non‐native or native can be complicated when parasite genera occur within both the NIS’ native range and its introduced range. We explored potential for spillover and spillback of lung parasites infecting Burmese pythons (Python bivittatus) in their invasive range (Florida). We collected 498 indigenous snakes of 26 species and 805 Burmese pythons during 2004–2016 and examined them for lung parasites. We used morphology to identify three genera of pentastome parasites, Raillietiella, a cosmopolitan form, and Porocephalus and Kiricephalus, both New World forms. We sequenced these parasites at one mitochondrial and one nuclear locus and showed that each genus is represented by a single species, R. orientalis, P. crotali, and K. coarctatus. Pythons are host to R. orientalis and P. crotali, but not K. coarctatus; native snakes are host to all three species. Sequence data show that pythons introduced R. orientalis to North America, where this parasite now infects native snakes. Additionally, our data suggest that pythons are competent hosts to P. crotali, a widespread parasite native to North and South America that was previously hypothesized to infect only viperid snakes. Our results indicate invasive Burmese pythons have affected parasite‐host dynamics of native snakes in ways that are consistent with parasite spillover and demonstrate the potential for indirect effects during invasions. Additionally, we show that pythons have acquired a parasite native to their introduced range, which is the initial condition necessary for parasite spillback.     

Diet and intestinal helminths in a population of perch, Perca flavescens

In 1967 and 1968 1310 Perca flavescens (Mitchill) were examined from Lake Opeongo, Ontario for changes in five diet categories and in incidence of eight intestinal helminths in relation to seasons, host size and sex. Male fish were less common than females and were smaller. A high proportion of fish (57.7 %) had empty stomachs, but of the four types of foods taken microcrustacea were high in spring, late summer and again in early winter; insects increased in summer with another peak in autumn; crayfish had a small peak in spring and a larger one in autumn; and fish were lowest in summer. Males ate more smaller foods (microcrustacea) than females, but females ate more larger foods (crayfish and fish); no sex difference was seen with regard to insects or empty stomachs. Male fish ate very few larger items, but females showed an increase in food size with increasing size of fish. There was no seasonality in incidence of fish free of all parasites, but two trematodes Bunodera sacculata Van Cleave & Mueller and B. luciopercae (Müller), and one cestode Proteocephalus pearsei La Rue showed seasonality with populations lowest in fish in summer; and one trematode Crepidostomum cooperi Hopkins and one nematode Dacnitoides cotylophora Ward & Magath showed seasonality with populations highest in summer. In addition one cestode Bothriocephalus sp., one nematode Spinitectus gracilis Ward & Magath and one acanthocephalan Leptorhynchoides thecatus (Linton) showed no seasonality, perhaps on account of the low incidence in the case of Bothriocephalus sp. and L. thecatus. No parasites were more common in males, but two (P. pearsei and L. thecatus) were more common in females. In both males and females, with increasing size fish, (i) fish free of all parasites decreased, but (ii) incidence of C. cooperi increased. Incidence of B. luciopercae, Bothriocephalus sp., S. gracilis and L. thecatus all increased with increasing size of fish only in females. The relationship between diet and incidence of intestinal helminths is discussed in the light of what is known of their life cycles. The exercise illustrates our ignorance of population ecology of fish parasites and the interactions of parasites and their host populations.     

Phylogeography and Demographic History of Chinese Black-Spotted Frog Populations (<Emphasis Type="Italic">Pelophylax nigromaculata</Emphasis>): Evidence for Independent Refugia Expansion and Secondary Contact

Background  

Pleistocene glaciations had considerable impact on phylogeographic patterns within and among closely related species of many vertebrates. Compared to Europe and North America, research on the phylogeography of vertebrates in East Asia, particularly in China, remains limited. The black-spotted frog (Pelophylax nigromaculata) is a widespread species in East Asia. The wide distribution of this species in China makes it an ideal model for the study of palaeoclimatic effects on vertebrates in East Asia. Our previous studies of P. nigromaculata revealed significant subdivisions between the northeast China populations and populations in other regions of the mainland. In the present study, we aim to see whether the deepest splits among lineages and perhaps subsequent genealogical divisions are temporally consistent with a Pleistocene origin and whether clade geographic distributions, with insight into expansion patterns, are similarly spatially consistent with this model.     

Perch (Perca fluviatilis L.) parasites reflect ecosystem conditions: a comparison of a natural lake and two acidic reservoirs in Finland

Parasite communities of perch were studied in a natural lake (Vetämäjärvi) and two reservoirs (the Kyrkösjärvi and Liikapuro reservoirs) located in Western Finland. All water bodies studied are small, shallow and humic. However, the reservoirs are more acidic than the lake (pH 5.9 and 5.3 vs. 6.4). Altogether, 18 parasite species were found, but the component communities were reduced in the harsh conditions of the reservoirs (12 and six species) as compared with the lake (17 species). In addition, the mean number of metazoan parasite specimens per fish was markedly lower in the reservoirs (64.3 and 14.3 specimens) than in the lake (116.1 specimens). Our prediction on the depauperation of parasite communities in reservoirs as compared with the lake was confirmed. Many ectoparasite groups were rare and most of the digenean parasites using molluscs as their intermediate host were absent from the reservoirs due to the inability of molluscs to tolerate the acidic water. The only digenean parasite found in the less acidic reservoir was Bunodera luciopercae. There were also species that preferred reservoirs as was expected. The protozoan ciliate Capriniana piscium benefiting acidic water and Acanthocephalus lucii, due to the abundance of its intermediate host, were most prevalent in the reservoir conditions.     

The occurrence and distribution of Dermocystidium percae (Mesomycetozoea) in perch (Perca fluviatilis) in the lower Thames Valley,UK

The occurrence and microhabitat distribution of Dermocystidium percae on perch (Perca fluviatilis) was investigated in four sites in the lower Thames Valley, south‐east England. Fish were infected at all sites, with the highest prevalence occurring in a commercial fishery and the lowest in a large impounded water storage reservoir. The microhabitat distribution of D. percae cysts on the perch favoured the dorsal and anal fins, in contrast to previous studies, although a single occurrence on the gills was reported. The role of host stress on the prevalence of D. percae is discussed.     

Mesofossils with platanaceous affinity from the Dakota Formation (Cretaceous) in Kansas, USA

The Platanaceae holds a basal position in the phylogeny of eudicots and therefore is of great interest to angiosperm systematists. The fossil record of the family is found in strata ranging from the Cretaceous to Recent in America, Europe and Asia. The research on the Platanaceae in the Dakota Formation can be traced back to 19th century; however, mesofossils of reproductive organs of the Platanaceae were never reported in the Midwest of North America before. This paper reports several specimens of Friisicarpus (Platanaceae) from the Dakota Formation in Kansas, USA. It complements the existing fossil records, and provides more information on reproductive biology of the family. The comparison with similar fossils from eastern North America and Europe provides some hints on biostratigraphy of the Cretaceous.     

Return to Beringia: parasites reveal cryptic biogeographic history of North American pikas

Traditional concepts of the Bering Land Bridge as a zone of predominantly eastward expansion from Eurasia and a staging area for subsequent colonization of lower latitudes in North America led to early inferences regarding biogeographic histories of North American faunas, many of which remain untested. Here we apply a host-parasite comparative phylogeographical (HPCP) approach to evaluate one such history, by testing competing biogeographic hypotheses for five lineages of host-specific parasites shared by the collared pika (Ochotona collaris) and American pika (Ochotona princeps) of North America. We determine whether the southern host species (O. princeps) was descended from a northern ancestor or vice versa. Three parasite phylogenies revealed patterns consistent with the hypothesis of a southern origin, which is corroborated by four additional parasite lineages restricted to O. princeps. This finding reverses the traditional narrative for the origins of North American pikas and highlights the role of dispersal from temperate North America into Beringia in structuring northern diversity considerably prior to the Holocene. By evaluating multiple parasite lineages simultaneously, the study demonstrates the power of HPCP for resolving complex biogeographic histories that are not revealed by characteristics of the host alone.     

Scaling up from epidemiology to biogeography: local infection patterns predict geographical distribution in fish parasites

Aim We investigated how the spatial distribution of parasites, measured as either their geographical range size or their frequency of occurrence among localities, relates to either their average local abundance or the variance in their abundance among localities where they occur. Location We used data on the abundance of 46 metazoan parasite species in 66 populations of threespine sticklebacks, Gasterosteus aculeatus, from Europe and North America. Methods For each parasite species, frequency of occurrence was calculated as the proportion of stickleback populations in which it occurred, and geographical range size as the area within the smallest possible polygon delimited using the coordinates of the localities where it occurred. Generalized linear models were used to assess how these two measures of spatial distribution were influenced by several predictor variables: geographical region (North America or Europe), life cycle (simple or complex), average local abundance, the coefficient of variation in abundance across localities, and median prevalence (proportion of infected hosts within a locality). Results Our analyses uncovered four patterns. First, parasites in North America tend to have higher frequencies of occurrence among surveyed localities, but not broader geographical ranges, than those in Europe. Second, parasite species with simple life cycles have wider geographical ranges than those with complex cycles. Third, there was a positive relationship between average abundance of the different parasite species and their frequency of occurrence, but not between average abundance and geographical range size. Fourth, the coefficient of variation in abundance covaried positively with both the frequency of occurrence and geographical range size across the different parasite species. Thus, all else being equal, parasites showing greater site‐to‐site variability in abundance occur in a greater proportion of localities and over a broader geographical area than those with a more stable abundance among sites. Main conclusions Local infection patterns are linked with large‐scale distributional patterns in fish parasites, independently of host effects, such that local commonness translates into regional commonness. The mechanisms linking parasite success at both scales remain unclear, but may include those that maintain the continuum between specialist and generalist parasites. Regardless, the observed patterns have implications for the predicted changes in the geographical distributions of many parasites in response to climate change.     

Effects of the allelopathically active macrophyte Myriophyllum spicatum on a natural phytoplankton community: a mesocosm study

The objective of this study was to identify potential effects of habitat conditions on parasite infection risk in reservoirs. For this, we compared parasite infection in 0+ perch (Perca fluviatilis L.) between reservoir sections: (1) along the longitudinal profile of Brno reservoir (inflow—main body—outflow), and (2) the transversal profile of Hamry reservoir (littoral and pelagic zones). Perch were predominantly infected with trophically transmitted endoparasites. Longitudinal parasite infection differed between sampling sections, showing different trends in particular parasite species between sections. The abundance of dominant Bunodera luciopercae was highest in the main body and lowest in the outflow, abundance of Proteocephalus sp. and Camallanus spp. decreased between the inflow and outflow, and abundance of Acanthocephalus lucii and ectoparasites (Gyrodactylus sp. and Argulus foliaceus) increased from the inflow to the outflow. Parasite diversity was higher in the outflow compared to other sections. No difference was observed in parasite abundance between littoral and pelagic perch subpopulations, though higher endoparasite diversity was found in the littoral zone. The results indicate that habitat type can influence parasite infection in perch through local food (intermediate host) availability. Fish–host behaviour is also discussed as a factor possibly influencing infection in perch.     

A Ceratopsian Dinosaur from the Lower Cretaceous of Western North America,and the Biogeography of Neoceratopsia

The fossil record for neoceratopsian (horned) dinosaurs in the Lower Cretaceous of North America primarily comprises isolated teeth and postcrania of limited taxonomic resolution, hampering previous efforts to reconstruct the early evolution of this group in North America. An associated cranium and lower jaw from the Cloverly Formation (?middle–late Albian, between 104 and 109 million years old) of southern Montana is designated as the holotype for Aquilops americanus gen. et sp. nov. Aquilops americanus is distinguished by several autapomorphies, including a strongly hooked rostral bone with a midline boss and an elongate and sharply pointed antorbital fossa. The skull in the only known specimen is comparatively small, measuring 84 mm between the tips of the rostral and jugal. The taxon is interpreted as a basal neoceratopsian closely related to Early Cretaceous Asian taxa, such as Liaoceratops and Auroraceratops. Biogeographically, A. americanus probably originated via a dispersal from Asia into North America; the exact route of this dispersal is ambiguous, although a Beringian rather than European route seems more likely in light of the absence of ceratopsians in the Early Cretaceous of Europe. Other amniote clades show similar biogeographic patterns, supporting an intercontinental migratory event between Asia and North America during the late Early Cretaceous. The temporal and geographic distribution of Upper Cretaceous neoceratopsians (leptoceratopsids and ceratopsoids) suggests at least intermittent connections between North America and Asia through the early Late Cretaceous, likely followed by an interval of isolation and finally reconnection during the latest Cretaceous.     

Paleobiogeographic relationships of angiosperms from the Cretaceous and early Tertiary of the North American area

The biogeographic affinities of the Cretaceous and early Tertiary angiosperm floras of the North American area (which includes Meso-America, and the Greater Antilles) have been the subject of considerable interest. Although recent treatments of isolated taxa have shown affinities between North American, European, east Asian and Neotropic floras, the relationships have not been quantified. This study compiles the records of fossils whose familial relationships seem secure. This provides a carefully culled, and uniformly presented review of the Cretaceous and Paleogene record from 1950 to 1989 and supplements LaMotte (1950). A subset of these records, which showed compelling evidence of subfamilial relationships, was analyzed to quantify the relationships of the Cretaceous, Paleocene, Eocene and Oligocene floras to other regions. The analysis suggests that for the entire period 24% of the fossil species had affinities with extant taxa from the Northern Hemisphere; 10% with taxa from the Northern Hemisphere that have a few species in South America; 17% with taxa from Eurasia; 3% with taxa with a disjunct Eurasian-South American pattern; 19% with taxa from South America and/or Africa; 8% with taxa from South America and/or Africa that have an important sister group in southeast Asia; 5% with taxa from the Old World; and 13% with taxa having other distribution patterns. Those fossils with affinities to Laurasian taxa are mostly found in the northern and western portions of the North American area. The fossils with affinities to South American and/or African taxa are found in the southern portions of North America, Meso-America, and the Greater Antilles. The taxa with disjunct distributions show both patterns. These patterns suggest that during this time there were wide-spread temperate elements, found throughout Laurasia; Boreotropical flora elements, distributed in North America, Europe and along the Tethys seaway to southeast Asia; and West Gondwana elements which show dispersion from South America across the proto-Caribbean. The paleobotanical data are compatible with current geological, paleontological and biogeographical studies.     

Die Parasitenkomplexe europäischer Diprionidae in ökologisch-evolutionsbiologischer Sicht

Parasite community of European Diprionidae from an ecological-evolutionary point of view Neodiprion sertifer, the only Eurasian species of this nearctic genus, is systematically and, due to its hibernation in the egg stage and its aestivation in the cocoon-stage, also biologically an outsider in the European Diprionid-fauna (Fig. 1). It is assumed that the ancestors of N. sertifer immigrated from western North America via Beringia to Eurasia during the Pleistocene period In spite of its exceptional status, this sawfly species has a rich parasitoid complex, characterized by several highly specific larval parasites, which, in size und diversity, is equivalent to the parasite-spectra of autochthonous European Diprionids such as Diprion pini, Microdiprion pallipes, etc. (Tab. 1 and 2). Based on a comparative analysis of these parasite complexes, a trial is made to explain 1. from which hosts the parasites of N. sertifer have originated and 2. which biological adaptations have allowed them to colonize the new host niche and to synchronize with the strictly univoltine life-cycle of N. sertifer. The boreo-montane Murodiprion pallipes has apparently played a key rôle as a source for parasitoid species of N. sertifer. Adaptation to the new host has been achieved by the acquisition of an obligatory summer diapause in such highly specific larval parasites as Exenterus abruptorius, Lamachus eques, Lophyroplectus luteator (Fig. 5) and in the «sertifer-form» of the egg parasite Dipriocampe diprioni (Fig. 3), whereas in Chrysonotomyia spp. the ability to develop as facultative hyperparasites has enabled them to bridge the summer gap when fresh host eggs are not available (Fig. 3 und 4).     

On the Distribution and Origin of Salix in the World

1. The distribution of Salix species among the continents. There are about 526 species of Salix in the world, most of which are distributed in the Northern Hemisphere with only a few species in the Southern Hemisphere. In Asia, there are about 375 species, making up 71.29 percent of the total in the world, including 328 endemics; in Europe, about 114 species, 21.67 percent with 73 endemics; in North America, about 91 species, 17.3 percent with 71 endemics; in Africa, about 8 species, 1.5 percent, with 6 endemics. Only one species occurs in South America. Asia, Europe and North America have 8 species in common (excluding 4 cultivated species). There are 34 common species between Asia and Europe, 14 both between Europe and North America and between Asia and North America, 2 between Asia and Africa. Acording to the Continental Drift Theory, the natural circumstances which promoted speciation and protected newly originated and old species were created by the orogenic movement of the Himalayas in the middle and late Tertiary. Besides, the air temperature was a little higher in Asia than in Europe and North America (except its west part) and the dominant glaciers were mountainous in Asia during the glacial epoch in the Quaternary Period. Then willows of Europe moved southwards to Asia. During the interglacial period they moved in opposite direction. Such a to-and-fro willow migration between Asia and Europe and between and North America occurred so often that it resulted in the diversity of willow species in Asia. Those species of willows common among the continents belong to the Arctic flora. 2. The multistaminal willows are of the primitive group in Salix. Asia has 28 species of multistaminal willows, but Europe has only one which is also found in Asia. These 28 species are divided into two groups, “northern type” and “southern type”, according to morphology of the ovary. The boundary between the two forms in distribution is at 40°N. The multistaminal willows from south Asia, Africa and South America are very similar to each other and may have mutually communicated between these continents in the Middle or Late Cretaceous Period. The southern type willows in south Asia are similar to the North American multistaminal willows but a few species. The Asian southern type willows spreaded all over the continents of Europe, Asia and North America through the communication between them before the Quaternany Period. Nevertheless, it is possible that the willows growing in North America immigranted through the middle America from South America. The Asian northern type multistaminal willows may have originated during the ice period. The multistaminal willows are more closed to populars in features of sexual organs. They are more primitive than the willows with 1-3 stamens and the most primitive ones in the genus. 3. The center of origin and development of willows Based on the above discussion it is reasonable to say that the region between 20°-40°N in East Asia is the center of the origin and differentiation of multistaminal willows. It covers Southern and Southwestern China and northern Indo-China Pennisula.     

THE EVOLUTION OF PARASITISM IN THE RED ALGAE: MOLECULAR COMPARISONS OF ADELPHOPARASITES AND THEIR HOSTS1

In several groups of parasites including insect, flowering plant, fungal, and red algal parasites, morphological similarities of the parasites and their specific hosts have led to hypotheses that these parasites evolved from their hosts. But these conclusions have been criticized because the morphological features shared by parasite and host may be the result of convergent evolution. In this study, we examine the hypothesis, originally put forth by Setchell, that adelphoparasitic red algae, that is, parasitic red algae that are morphologically very similar to their hosts, evolved from their specific red algal hosts. Rather than comparing morphological features of parasites and hosts, small-subunit 18S nuclear ribosomal DNA and the internal transcribed spacer regions (ITSs) of the nuclear ribosomal repeat are compared for five parasites, their hosts, and related nonhosts from four red algal orders. These comparisons reveal that each of these adelphoparasites has evolved either directly from the host on which it is currently found, or it evolved from some other taxon that is closely related to the modern host. The parasites Gardneriella tuberifera, Rhodymeniocolax botryoides, and probably Gracilariophila oryzoides evolved from their respective hosts Sarcodiotheca gaudichaudii, Rhodymenia pacifica, and Gracilariopsis lemaneiformis, respectively. The parasite Faucheocolax attenuata evolved from either Fauchea laciniata or Fauchea fryeana and subsequently radiated onto the other host species. Presently this parasite is found on both hosts. Lastly, some parasitic genera such as Plocamiocolax are polyphyletic in their origins. A species of Plocamiocolax from an Antarctic Plocamium cartilagineum appears to have evolved from its host whereas the common Plocamiocolax pulvinata that occurs along the west coast of North America likely evolved from Plocamium violaceum and radiated secondarily onto its present day host, Plocamium cartilagineum.     

VARIATION BETWEEN POPULATIONS AND LOCAL ADAPTATION IN ACANTHOCEPHALAN‐INDUCED PARASITE MANIPULATION

Many trophically transmitted parasites manipulate their intermediate host phenotype, resulting in higher transmission to the final host. However, it is not known if manipulation is a fixed adaptation of the parasite or a dynamic process upon which selection still acts. In particular, local adaptation has never been tested in manipulating parasites. In this study, using experimental infections between six populations of the acanthocephalan parasite Pomphorhynchus laevis and its amphipod host Gammarus pulex, we investigated whether a manipulative parasite may be locally adapted to its host. We compared adaptation patterns for infectivity and manipulative ability. We first found a negative effect of all parasite infections on host survival. Both parasite and host origins influenced infection success. We found a tendency for higher infectivity in sympatric versus allopatric combinations, but detailed analyses revealed significant differences for two populations only. Conversely, no pattern of local adaptation was found for behavioral manipulation, but manipulation ability varied among parasite origins. This suggests that parasites may adapt their investment in behavioral manipulation according to some of their host's characteristics. In addition, all naturally infected host populations were less sensitive to parasite manipulation compared to a naive host population, suggesting that hosts may evolve a general resistance to manipulation.     

A second hadrosauroid dinosaur from the early Late Cretaceous of Zuoyun,Shanxi Province,China

A second basal hadrosauroid dinosaur, Zuoyunlong huangi gen. et sp. nov., is reported from the early Late Cretaceous Zhumapu Formation in Zuoyun County, Shanxi Province, northern China. Zuoyunlong preserves a partial right ilium and ischium and is unique in having a very short postacetabular process 50% as long as the iliac central plate. Our cladistic analysis recovers Zuoyunlong as the most basal Late Cretaceous hadrosauroid, with a sister taxon relationship with Probactrosaurus from the late Early Cretaceous of Inner Mongolia. Including Zuoyunlong, four Cenomanian basal hadrosauroids have been recorded, and the two taxa in North America (Eolambia and Protohadros) represent the earliest known hadrosauroids outside of Asia. In the light of the proposed phylogenetic topology and biogeographic data, the discovery of Zuoyunlong indicates that the first dispersal of hadrosauroids from Asia to North America probably happened around the boundary between the Early and Late Cretaceous.