Using genetic and morphological analysis to distinguish endangered taxa from their hybrids with the cultivated exotic pest plant <Emphasis Type="Italic">Lantana strigocamara</Emphasis> (syn: <Emphasis Type="Italic">Lantana camara</Emphasis>)

Because highly invasive species can rapidly assimilate rare taxa, we questioned whether two Florida endangered Lantana depressa varieties existed 21 years after Sanders documented their widespread hybridization with exotic Lantana strigocamara, and whether morphological traits could accurately discriminate genetic individuals. Stepwise discriminant analysis of morphological characters discriminated the three taxa, correctly classifying 98, 91, 89% of L. strigocamara, L. depressa var. depressa, and var. floridana. Hybrids blurred taxonomic distinctions of varieties and reduced classification accuracy by 7–17%. Species-specific Random Fragment Length Polymorphism (RFLP-PCR) confirmed hybridization has occurred. Intersimple Sequence Repeat (ISSR) fingerprints analyzed with STRUCTURE identified three groups indicating introgression. Morphological traits significantly, but weakly correlated with q ratios (P = 0.0001; r ² = 0.45). Although L. strigocamara introgression is widespread and ongoing, wild populations contain individuals that are predominantly L. depressa genome, supporting actions to remove adventive L. strigocamara, prevent its sale, and promote sales of genetically confirmed natives.     

The niche-width variation hypothesis reconfirmed: Validation by genetic diversity in the sessile intertidal cirripedes Chthamalus stellatus and Euraphia depressa (Crustacea,Chthamalidae)

Genetic diversity in a pair of cirripede species, based on electrophoretic analysis of 25 gene loci, is higher for Chthamalus stellatus, the species with a broader biogeographical distribution, and hence, with a broader ecological niche, than that of Euraphia depressa. Comparing the genetic diversity within E. depressa we again report a higher genetic diversity among the specimens exposed to solar radiation (living in the wider ecological niche) versus the specimens confined to the sheltered dark environments in caves or under boulders. The indices of genetic diversity used in this study are polymorphism, heterozygosity, mean number of alleles per locus and gene diversity. We conclude that the niche-width variation hypothesis has been confirmed in this pair of species: genetic diversity is positively correlated with niche breadth.     

Light and scanning electron microscopy of the embryos and glochidia larvae of the Australian freshwater bivalve Hyridella depressa (Hyriidae)

Summary

As is characteristic of freshwater Unionacea, the Australian species Hyridella depressa incubates its young within the demibranchs of its modified gills. The development of H. depressa was documented through light and scanning electron microscopic examination of the marsupial pouch in the inner demibranchs of brooding females. Transition from the gastrula to the glochidial stage was accompanied by a split in the larval integument. The glochidia of H. depressa have subtriangular shell valves each having a blunt tooth at the ventral margin. Each glochidium has a pair of hooks, one on each valve internal to the tooth. These hooks are used to attach to its fish host and are structured to interlock when the valves snap shut. One or two tufts of sensory hairs are located on the internal surface of the mantle dorsal to the hook, while a single tuft, encircled by a collar-like structure, is located centrally. The valves are pitted by pores and have concentric lines along the margins. Due to the similarity and phenotypic plasticity of adult Hyridella species, the morphology of their glochidia has potential for use as a taxonomic tool. In comparison to related species, the glochidia of H. depressa are medium-sized with a mean length of 243 μm and a mean height of 249 μm. The number of glochidia present in the gills was measured to determine the reproductive output of H. depressa. The embryos of an unknown mite, Unionicola sp., form cysts within the gill tissue of H. depressa and the adult mites were observed on the surface of the gills.     

Preliminary evaluation of non-native rainbow trout (Oncorhynchus mykiss) impact on the Cederberg ghost frog (Heleophryne depressa) in South Africa’s Cape Fold Ecoregion

We evaluated the impact of non-native rainbow trout Oncorhynchus mykiss on a population of endemic Cedarberg ghost frog Heleophryne depressa in the upper Krom River (Olifants-Doring River Catchment, Cape Fold Ecoregion). We compared H. depressa abundance (using kick-sampling and underwater video analysis) and environmental conditions between sites above and below a waterfall that marks the upper distribution limit of O. mykiss. Heleophryne depressa abundance was significantly greater above the waterfall than that below it, and, because there was no significant difference in measured environmental variables, O. mykiss presence is identified as the most likely explanation for the observed decrease in H. depressa abundance.     

An analysis of allozymic characters of four species of New Zealand Amalda (Gastropoda: Olividae: Ancillinae)

Abstract

This contribution reports the results of an electrophoretic analysis of four species of the molluscan genus Amalda. The results of this analysis confirm that four taxonomically defined species are also biologically distinct, that their often considerable morphological variability is a within-species phenomenon, and that a previously undescribed form of A. depressa, which is genetically and morphologically distinct, occurs in the Bay of Islands. The genetic data were analysed cladistically and the resulting phylogenetic classification supports that based on morphology.     

The antennae of damselfly larvae

The larval antennal sensilla of two Zygoptera species, Calopteryx haemorroidalis (Calopterygidae) and Ischnura elegans (Coenagrionidae) are investigated with SEM and TEM. These two species have different antennae (geniculate, setaceous) and live in different environments (lotic, lentic waters). Notwithstanding this, similarities in the kind and distribution of sensilla are outlined: in both species the majority of sensilla types is located on the apical portion of the antenna, namely a composed coeloconic sensillum (possible chemoreceptor), two other coeloconic sensilla (possible thermo-hygroreceptors) and an apical seta (direct contact mechanoreceptor). Other mechanoreceptors, such as filiform hairs sensitive to movements of the surrounding medium or bristles positioned to sense the movements of the flagellar segments, are present on the antenna. Similarities in the antennal sensilla types and distribution are observed also with other dragonfly species, such as Onychogomphus forcipatus and Libellula depressa. A peculiar structure with an internal organization similar to that of a gland is observed in the apical antenna of C. haemorroidalis and I. elegans and it is present also in O. forcipatus and L. depressa. The possible function of this structure is at the moment unknown but deserves further investigations owing to its widespread presence in Odonata larvae.     

Saxifraga depressa and Saxifragetum depressae: an endemic species and association of the western Dolomites (Italy)

Saxifraga depressa grows only on the summits of eleven siliceous massives in the western Dolomites. It is restricted to the habitat of steep N-faced screes lying above 2000 m. Syntaxonomically, Saxifraga depressa characterizes the association Saxifragetum depressae which is here described for the first time with two subassociations. With respect to the closely allied Oxyrietum digynae, the Saxifragetum depressae colonizes debris richer in fine material. The soil pH in the habitats of the Saxifragetum depressae varies from acid to slightly basic, mainly as a result of lithological differences in the parent rocks. The habitats having a subneutral or basic soil are colonized by a well-defined subassociation of the Saxifragetum depressae, which is differentiated by some basiphilous species.     

Effects of grazer identity on the probability of escapes by a canopy-forming macroalga

Through their grazing activities limpets have an important role in controlling macroalgal abundance and as a result the structure and dynamics of rocky shore assemblages. Using two congeneric limpet species, with different biogeographic distributions, and whose ranges are expected to alter with climatic warming, we separated the magnitude of their grazing activity over time and the subsequent consequence for macroalgal growth.The northern/boreal limpet, Patella vulgata (L.), consistently grazed more than the southern/lusitanian limpet, P. depressa (Pennant), particularly during spring and summer when P. depressa was reproductively active. Individuals of Fucus vesiculosus (L.) that settled during this time were able to grow to a size where they escaped the grazing activities of P. depressa, resulting in mature F. vesiculosus being present in all P. depressa treatments. In contrast, P. vulgata, which was not reproductively active during this period, exhibited no reduction in its grazing activity and prevented macroalgae from growing in experimental treatments. It therefore appears that P. vulgata has a stronger role, than P. depressa, in controlling macroalgal abundance on shores of southwest Britain.We present a conceptual model highlighting the direct and indirect interactions between these two limpet species and F. vesiculosis. If as predicted, under current warming scenarios, P. depressa becomes the dominant limpet on shores of southwest Britain there will be subsequent changes in rocky shore community structure and ecosystem functioning. Our research emphasises that even closely related species with similar ecological niches can exhibit different behaviours that fundamentally alter their biological interactions with other organisms leading to idiosyncratic responses to predicted changes in climate.     

Larval selection of substrate by the Bryozoa discoporella and Cupuladria

Summary The mineralogy, shape, and size distribution of sand grains which form the nucleus for colonial growth in Discoporella umbellata depressa and Cupuladria doma have been examined and compared to these same parameters in the sediment from which the species were collected. These bryozoa, occurring on the continental shelf of Georgia, encrust sand grains. The diameters of the encrusted grains greatly exceed the mean diameter of particles in the associated sediment. D. umbellata depressa encrusts larger grains than does C. doma. Encrusted grains are composed of quartz and rock fragments. No zoaria of either species were found that had encrusted carbonate grains despite the fact that such grains form an important fraction of the sediment in the study area. Larval selection of fixation sites on the basis of grain size and mineralogy is suggested. It is further suggested that these sedimentary parameters may partially explain the fact that both bryozoan species are abundantly present on the continental shelf of the southeastern United States but are nearly absent from the continental slope.

---

Résumé La minéralogy, la configuration et le classement par ordre de grandeur des grains de sable qui forment le centre pour le grandissement colonial dans Discoporella umbellata depressa et Cupuladria doma ont été examinés et comparés à ces mêmes paramèters dans les alluvionnements d'où venaient les especès mentionnées. Ces bryozoaires, qui se trouvent sur le banc continental de Georgie encro?tent des grains de sable. Les diamèters des grains encro?tés dépassent de beaucoup le diametre moyen des particules dans les alluvionnements associés. D. umbellata depressa encro?te de plus grands grains que C. doma. Les grains encro?tés se composent de quartz et de fragments de rocker. On n'a trouvé aucun zoaria des deux especes qui avait encroute des grains de carbonate, malgré le fait que de tels grains font une importante fraction de l'alluvionnement dans Faire de notre spécialization. On suggère un choix larvaire des sites de fixation, basé sur la grandeur des grains et la minéralogy. De plus, on suggerè que ces parametrès sédimentaires pourraient expliquer en partie le fait que tous les deux espèces bryozoaires sont présentes en grand nombre sur le bane continental du sud-est des Etats-Unis, mais sont à peu près absentes du talus continental.

     

Are behavioural traits in prey sensitive to the risk imposed by predatory fish?

1. Behavioural differences among prey species may result from evolutionary adaptations that facilitate coexistence with different predators and influence vulnerability to predators. It has been hypothesised that prey species modify their behaviour in relation to the risk posed by particular predators. 2. We examined the relationship between anti‐predator behaviour and predation risk in five species of larval odonates in combination with three predatory fish species (perch, gudgeon and rudd) that differ in foraging behaviour. The odonates, Platycnemis pennipes, Coenagrion puella, Lestes sponsa, Sympetrum striolatum and Libellula depressa, differ with regard to their life cycle and habitat, including water depth, occurrence in temporary ponds and co‐existence with fish. 3. The odonate species differed in their response to fish: (i) Two species showed a flexible response. Larval C. puella reduced activity in the presence of fish, regardless of species, whereas L. depressa altered their activity only in the presence of gudgeon. (ii) Independent of fish species, all odonates except L. depressa exhibited spatial avoidance of fish. This was interpreted as a more general anti‐predator response. (iii) In some cases the odonates showed no response to predators and their behaviour was thus independent of predation risk. 4. Our results confirm that all odonates responded to the presence of at least some predatory fish, and that some odonate species discriminated between fish species. However, we found no significant correlation between behavioural modifications and predation risk, indicating that anti‐predator responses and predation risk depend on the particular predator and the species being preyed on.     

Silurian Leptaeninae (Brachiopoda) from Gotland, Sweden

Strophomenid brachiopods belonging to the generaLeptaena andLepidoleptaena are described from the uppermost Llandovery — Ludlow succession of Gotland, Sweden. In Gotland,Lepidoleptaena comprises the single speciesL. poulseni, andLeptaena includes four species:L. rhomboidalis, L. sperion, L. depressa andL. parvirugata n. sp.L. depressa shows a considerable amount of morphological variation, which is recognised in the two new subspeciesLeptaena depressa visbyensis n. ssp. from the Llandoverian — Wenlockian Visby Formation, andL. depressa lata n. ssp. from the mid-Wenlockian Slite Group. The distribution of the different species is largely substrate-dependent, withLeptaena rhomboidalis andLepidoleptaena poulseni adapted to high-energy environments with firm substrates, whereas the remaining species preferred fine-grained substrates in low-energy environments.      

Three species of Pagodia (Corynexochida,Trilobita) from the Furongian (Cambrian) of northern Anhui,China and their intraspecific variation

More than one thousand cranidia, librigenae, and pygidia of the trilobite Pagodia were collected from the Cambrian (upper Jiangshanian through Stage 10) at Fenghuangshan in northern Anhui, China. They were identified as Pagodia lotos Walcott, 1905, Pagodia depressa (Walcott, 1905), and Pagodia bia Walcott, 1905. Based on one rare nearly complete exoskeleton of P. depressa and comparisons among the three species of Pagodia, the redefinition for those species is attempted as follows. Pagodia lotos: Glabella rectangular, slightly convergent anteriorly; anterior border ridge-like, anterior border furrow deep; pygidium semicircular, axis tapered rearward, with 4 axial rings and a terminal piece. P. depressa: Cranidium subquadrate, highly convex; glabella cylindrical, convergent anteriorly; pygidium semicircular. P. bia: Glabella rectangular, constricted in the midlength; fixigena wide (tr.); anterior border very narrow (sag.) and ridge-like; pygidium semicircular with wide borders; pygidial axis ended closer to the pygidial border furrow. We also discuss their intraspecific variations, commonly seen on the exfoliated specimens: palpebral ridge evident or obliterated, the length (sag.) of anterior area variable, the decoration of exoskeleton surface (with granules variable in size, convex or pitted).     

Molecular Phylogenetics and Biogeography of the Caribbean-Centered <Emphasis Type="Italic">Croton</Emphasis> Subgenus <Emphasis Type="Italic">Moacroton</Emphasis> (Euphorbiaceae s.s.)

Initial molecular phylogenetic studies established the monophylly of the large genus Croton (Euphorbiaceae s.s.) and suggested that the group originated in the New World. A denser and more targeted sampling of Croton species points to a South American origin for the genus. The nuclear and chloroplast genomes indicate a different rooting for the phylogeny of Croton. Although we favor the rooting indicated by the chloroplast data our conclusions are also consistent with the topology inferred from the nuclear data. The satellite genera Cubacroton and Moacroton are embedded within Croton. These two genera are synonimized into Croton and a new subgenus, Croton subgenus Moacroton, is circumscribed to include them and their allied Croton species. Croton subgenus Moacroton is morphologically characterized by a primarily lepidote indumentum, bifid or simple styles, and pistillate flowers with sepals that are connate at the base. This newly circumscribed subgenus is found from North America to South America, and in contrast to the majority of Croton species most of its members are found in mesic habitats. The group is most diverse in the greater Caribbean basin. A molecular clock was calibrated to the phylogeny using the available Euphorbiaceae fossils. The timing and pattern of diversification of Croton is consistent with both the GAARlandia and Laurasian migration hypotheses. A single species, Croton poecilanthus from Puerto Rico, is placed incongruently by its nuclear and chloroplast genomes. The possibility of this species being of hybrid origin is discussed.      

Diversity of rickettsial pathogens in Columbian black‐tailed deer and their associated keds (Diptera: Hippoboscidae) and ticks (Acari: Ixodidae)

Cervids host multiple species of ixodid ticks, other ectoparasites, and a variety of rickettsiae. However, diagnostic test cross‐reactivity has precluded understanding the specific role of deer in rickettsial ecology. In our survey of 128 Columbian black‐tailed deer (Odocoileus hemionus columbianus (Richardson)) and their arthropod parasites from two northern Californian herds, combined with reports from the literature, we identified four distinct Anaplasma spp. and one Ehrlichia species. Two keds, Lipoptena depressa (Say) and Neolipoptena ferrisi Bequaert, and two ixodid ticks, Ixodes pacificus Cooley and Kohls and Dermacentor occidentalis Marx, were removed from deer. One D. occidentalis was PCR‐positive for E. chaffeensis; because it was also PCR‐positive for Anaplasma sp., this is an Anaplasma/Ehrlichia co‐infection prevalence of 4.3%. 29% of L. depressa, 23% of D. occidentalis, and 14% of deer were PCR‐positive for Anaplasma spp. DNA sequencing confirmed A. bovis and A. ovis infections in D. occidentalis, A. odocoilei in deer and keds, and Anaplasma phagocytophilum strain WI‐1 in keds and deer. This is the first report of Anaplasma spp. in a North America deer ked, and begs the question whether L. depressa may be a competent vector of Anaplasma spp. or merely acquire such bacteria while feeding on rickettsemic deer.     

Studies on Leaf Oils of Citrus Species

Leaf oils from 6 domestic citrus species were analysed by gas chromatography and 32 compounds were identified as constituents of one or more oils. Most components present were common to all 6 citrus leaf oils, but the percent composition of some components, i.e. β-pinene, limonene, β-phellandrene, γ-terpinene, p-cymene, p-α-dimethylstyrene, citronellal, linalool and thymol methyl ether, differed considerably from species to species. For example, γ-terpinene is a main component (36.5%) of Shiikuwasha (Citrus depressa Hayata), but is a trace in leaf oils from Kawabata-mikan (C. aurea Tanaka) and Otaheite-orange (C. limonia Osbeck var. otaitensis Tanaka). Yuzu (C. Junos Sieb. ex Tanaka) is characterized by relatively high contents of β-phellandrene (11.2%) and p-α-dimethylstyrene (6.7%), which are minor constituents in the other 5 citrus leaf oils. Otaheite-orange is characterized by high contents of limonene (39.7%) and citronellal (10.0%).     

Morphological and functional heterogeneity in olfactory perception between antennae and maxillary palps in the pumpkin fruit fly,Bactrocera depressa

The morphology and ultrastructure of the olfactory sensilla on the antennae and maxillary palps were investigated through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and their responses to five volatile compounds were measured using electroantenogram (EAG) and electropalpogram (EPG) techniques in the pumpkin fruit fly, Bactrocera depressa (Shiraki; Diptera: Tephritidae). Male and female B. depressa displayed distinct morphological types of olfactory sensilla in the antennae and maxillary palps, with predominant populations of trichoid, basiconic, and coeloconic sensilla. Basiconic sensilla, the most abundant type of olfactory sensilla in the antennae, could be further classified into two different types. In contrast, the maxillary palps exhibited predominant populations of a single type of curved basiconic sensilla. High‐resolution SEM observation revealed the presence of multiple nanoscale wall‐pores on the cuticular surface of trichoid and basiconic sensilla, indicating that their primary function is olfactory. In contrast, coeloconic sensilla displayed several longitudinal grooves around the sensillum peg. The TEM observation of individual antennal olfactory sensilla indicates that the basiconic sensilla are thin‐walled, while the trichoid sensilla are thick‐walled. The profile of EAG responses of male B. depressa was different from their EPG response profile, indicating that the olfactory function of maxillary palps is different from that of antennae in this species. The structural and functional variation in the olfactory sensilla between antennae and maxillary palps suggests that each plays an independent role in the perception of olfactory signals in B. depressa.     

Multiple host-ant use by the predatory social parasite <Emphasis Type="Italic">Phengaris</Emphasis> (=<Emphasis Type="Italic">Maculinea</Emphasis>) <Emphasis Type="Italic">arion</Emphasis> (Lepidoptera,Lycaenidae)

Phengaris (=Maculinea) arion is an endangered social parasite of Myrmica ants, and for a very long time was considered as specific to Myrmica sabuleti. Previous studies carried out in Poland suggested some discrepancies within this assumption, and therefore a much more intensive survey was undertaken. The host ant use of P. arion was studied at five sites in different types of biotopes in Poland, i.e. xerothermal grasslands where Thymus pulegioides was used as a larval food plant by the butterfly, and more or less sandy biotopes with Thymus serpyllum. Altogether nine Myrmica species were recorded, and considerable variation in species composition and density of nests was recorded. At four localities M. sabuleti proved to be the most common ant. A total of 529 Myrmica nests were examined, and only 20 of them contained larvae and pupae of P. arion. Host ants belonged to five different species, i.e. M. sabuleti, Myrmica scabrinodis, Myrmica schencki, Myrmica lobicornis and Myrmica hellenica. Only at one site (NE Poland) was a significant heterogeneity in parasitation rates among Myrmica species detected. M. lobicornis was the most often infested ant there, which may suggest local specialisation of the butterfly. Overall low parasitism rates may explain the vulnerability of P. arion in Central Europe but further studies are also necessary.     

Molecular phylogeny and divergence times of Onosma (Boraginaceae s.s.) based on nrDNA ITS and plastid rpl32‐trnL(UAG) and trnH–psbA sequences

We analysed 87 species of Onosma (Boraginaceae) from throughout its distribution range to investigate its evolutionary history. Using nrDNA ITS and two plastid (rpl32‐trnL_(UAG) and trnH–psbA) markers, we reconstructed phylogenetic relationships within Onosma by conducting maximum parsimony, maximum likelihood, Bayesian, and BEAST analyses. The analyses revealed that Onosma as currently circumscribed is not monophyletic. However, the vast majority of Onosma species appear to belong to a single clade, the so‐called Onosma s.s. Outside of this core clade is a clade containing O. rostellata, a subclade of Sino‐Indian species and Maharanga emodii. Podonosma orientalis (as O. orientalis) appear only distantly related to Onosma but is more closely related to Alkanna, as also suggested in previous molecular studies. The Onosma s.s. clade includes all representatives of O. sect. Onosma, and encompasses three subsections, i.e. Onosma, Haplotricha and Heterotricha, corresponding to asterotrichous, haplotrichous and heterotrichous groups, respectively, but none of these subsections was retrieved as monophyletic. We observed significant incongruence between nuclear and chloroplast phylogenies regarding the phylogenetic status of the heterotrichous group. A dozen of the Iranian haplotrichous species formed a lineage which may not hybridize with asterotrichous species. Divergence time estimates suggested that the early radiation of Onosma s.l. took place at the Oligocene‐Miocene boundary and the diversification within Onosma s.s. occurred during middle to late Miocene and Pliocene.     

Hormonal Control of Germination under Saline Conditions of Three Halophytic Taxa in the Genus Suaeda

The interaction between hormones and salinity on seed germination of three halophytic taxa in the genus Suaeda: S. maritima (L.) Dum. var. flexilis Focke and var. macrocarpa Moq., and S. depressa (Pursh) Wats, was studied. Exogenous applications of kinetin and gibberellic acid (GA3) were applied in order to determine if either of these growth-promoting hormones would promote germination in the two dormant taxa, Suaeda depressa and S. maritima var. flexilis and to see if osmotically induced dormancy by NaCl could be alleviated. Our results indicate that gibberellic acid is capable of breaking dormancy in these species with dormant seeds, but kinetin proved to be ineffective. A seed dormancy that was induced by osmotic stress could also be alleviated by treatments with gibberellic acid. Endogenous concentrations of both cytokinins and gibberellins were measured in seeds exposed to osmotic stress (0.85 M NaCl), and we found a reduction in cytokinin activity in these three taxa. Gibberellin-like activity was reduced in S. depressa when seeds were soaked in 0.85 M NaCl.