Predation by Callinectes sapidus (Rathbun) within Spartina alterniflora (Loisel) marshes

This study examined predation by the blue crab, Callinectes sapidus Rathbun, within intertidal Spartina alterniflora (Loisel) marshes of Dauphin Island, Alabama. Species and size preferences displayed by the predator when foraging within the marsh were investigated using nektonic, epifaunal, and infaunal prey populations including Fundulus similis Baird and Girard, Littorina irrorata Say, and Geukensia demissa Dillwyn.

Short-term field experiments involving the use of predator inclusion cages, in which the relative abundances of all prey species and the density of macrophyte vegetation were manipulated, indicated that mean mortality differed significantly among species. Blue crabs exhibited a distinct species preference for Littorina, and to a lesser extent, for Fundulus. However, the predator rarely choses infaunal individuals. Within predator inclusion cages, size selection by the crabs among three size classes of each prey was evident for Littorina and Fundulus but not for Geukensia. Blue crabs tended to select intermediate-sized snails and large fish while not exhibiting a size preference for infaunal bivalves.

In the marsh, mean percentage of the Littorina population within the 14–18 mm size class exhibited an increased mortality as compared to two other size classes, which was negatively correlated with increasing tidal height. Such a relationship may have been due to a decreasing gradient of crab predation associated with increasing tidal height. Geukensia size class distributions showed little evidence of differences along the tidal height gradient. No data are available for Fundulus, a mobile species which would not experience such differential predation along a marsh gradient.

In comparing crab predation patterns among prey species, it is apparent that Callinectes utilizes prey species differentially. Such differential utilization may be based on optimization of energy yield and minimization of energy expenditure. Thus, the preference of blue crabs for nektonic and epifaunal prey is hypothesized to be the result of a smaller energy expediture as a result of the crab's visual evaluation of these prey. Infaunal prey species (e.g., Geukensia) require a greater energy investment because of the necessity of excavating the prey item. Such prey also allow little selection by size because of being cryptic.     

The Peniophorella praetermissa species complex (Basidiomycota)

The corticioid basidiomycete Peniophorella praetermissa has long been regarded as a morphologically variable species complex. An ITS-based phylogenetic study based on a worldwide sampling was carried out using parsimony and Bayesian inference. The resulting trees feature three major clades, further divided into well-supported subclades. These could be considered as distinct species, a contention that is further supported by crossing test data. Only two out of the eight phylogenetic lineages identified can be distinctly morphologically characterized: P. odontiaeformis and P. subpraetermissa. P. odontiaeformis is an odontioid species with a paleotropical distribution whereas the taxa in the remaining subclades have smooth basidiomata and are distributed in temperate areas. P. subpraetermissa is known only from the type collection and is distinguished microscopically by its reddish brown apically encrustated cystidia. Taxa in the remaining subclades are impossible to distinguish from each other morphologically, and therefore, are viewed as a species complex, P. praetermissa s. lat. One of the subclades, which is widely distributed but restricted to the Northern hemisphere, is proposed to represent P. praetermissa s. str. An epitype is selected from the same area as the holotype, among the specimens studied here. However, the geographically most widespread clade with many representatives from both hemispheres is here referred to as P. pertenuis, a taxon that was previously considered a synonym to P. praetermissa.     

Ascomycetes on Polytrichadelphus aristatus (Musci)

Fourteen herbarium specimens of Polytrichadelphus aristatus (Polytrichaceae, Musci) from the northern Andes were found to be colonized by ascomycetes. Thirty fungal specimens are indicated representing nine species and six genera. They belong to the first records of bryophilous fungi of northern South America. Five taxa are proposed as new: the genus Aphanotria, and the species A. paradoxa, Bryochiton macrosporus, Bryorella imitans, and Massarina polytrichadelphi. Most frequently found were Rogellia triseptata with six and Bryochiton macrosporus with five records. Four species develop their ascomata between the photosynthetic leaf lamellae, three are immersed within the abaxial side of the leaf nerve and two grow below the adaxial cuticle. The hypocrealean A. paradoxa, which has huge but almost invisible ascomata, merits special attention. Apart from a pronounced rostrum, these are completely immersed within the leaf nerve but longitudinally orientated occupying a type of microniche hitherto unknown. Hyphae of several species attack the thick-walled stereids of the leaf nerve and strongly contribute to leaf decomposition. Polytrichadelphus aristatus has an assemblage of parasitic ascomycetes quite different from that of P. magellanicus from southern South America.     

Body musculature of Stylochaeta scirtetica Brunson, 1950 and Dasydytes (Setodytes) tongiorgii (Balsamo, 1982) (Gastrotricha: Dasydytidae): A functional approach

Species of the freshwater gastrotrich taxon Dasydytidae show a set of conspicuous structural and behavioural adaptations to a semi-planktonic life. Conspicuously, most dasydytids have several groups of strong, moveable spines that can actively be abducted to perform saltatory movements, change the overall direction of locomotion, or enable the animals to rest in a defensive position. So far, there are only vague ideas of how these spine movements are achieved in dasydytid species. In order to gain insight into the possible morpho-functional coupling of body musculature and motile spines, we have carried out a study targeting the muscular system in two species of Dasydytidae by means of phalloidin staining and confocal laser scanning microscopy.

For spine movements in both species studied, Stylochaeta scirtetica and Dasydytes (Setodytes) tongiorgii, we have identified an antagonistic system of segmented longitudinal and oblique somatic muscle pairs. In both species, contraction of the musculi obliqua abduct the paired groups of ventro-lateral spines; contraction of the segments of musculi laterales causes their adduction.

A comparison of the muscular system of the studied species to that of other gastrotrichs reveals several homologous muscle pairs, visceral as well as somatic, that might be features of the stem species of a clade comprising all Paucitubulatina exclusive of Xenotrichulidae. The pairs of oblique somatic muscles are most probably an autapomorphy of Dasydytidae.     

Antechiniscus in Australia: Description of Antechiniscus moscali sp. n. and Redescription of Antechiniscus parvisentus (Horning & Schuster, 1983) (Heterotardigrada: Echiniscidae)

Two species of the genus Antechiniscus have been found in Nothofagus forests in Australia. The new species A. moscali sp. n. is described. The New Zealand species A. parvisentus (Horning & Schuster, 1983) is redescribed from type material and from the new material from Australia. The taxonomic status of the two species within the genus is discussed.     

Evolution in Carex L. sect. Spirostachyae (Cyperaceae): A molecular and cytogenetic approach

Carex sect. Spirostachyae comprises 25 species displaying the centre of diversity in Eurasia. Phylogenetic analysis of the ITS nrDNA region of 20 species of sect. Spirostachyae, six species of sect. Ceratocystis, five species of sect. Elatae, and eight outgroup species reveals that neither sect. Spirostachyae nor sect. Elatae is monophyletic. With the exclusion of Carex cretica, the 19 species of sect. Spirostachyae studied form a clade with the five species of tropical-subtropical sect. Elatae. Taxonomy of the core Spirostachyae is not only mostly in agreement with our phylogenetic hypothesis, but also with ecological and new cytogenetic results. Two main groups with different chromosome numbers and edaphic preferences are identified in the core Spirostachyae. One includes primarily acidophilous species with high chromosome numbers (2n=(64)68–84), whereas the other one includes mainly basophilous species with lower chromosome numbers (2n=60–74(75)). Chromosome-number variation is extremely different in the core Spirostachyae, showing great stability in some widespread species (e.g. Carex extensa) but an active chromosome evolution – faster chromosomal rearrangements, fusion and fission events than ITS nucleotide substitutions – in more restricted species (e.g. Carex troodi). Biogeography of the two amphiatlantic pairs of species reveals two independent colonizations of South America from the European continent. The geographical barrier of the Strait of Gibraltar has played different roles in the course of evolution of this section, acting as an effective barrier to gene flow in one case (Carex helodes) but as a limited barrier or recent separation in two others (Carex distans, Carex punctata).     

Chorioactidaceae: a new family in the Pezizales (Ascomycota) with four genera

Molecular phylogenetic and comparative morphological studies provide evidence for the recognition of a new family, Chorioactidaceae, in the Pezizales. Four genera are placed in the family: Chorioactis, Desmazierella, Neournula, and Wolfina. Based on parsimony, likelihood, and Bayesian analyses of LSU, SSU, and RPB2 sequence data, Chorioactidaceae represents a sister clade to the Sarcosomataceae, to which some of these taxa were previously referred. Morphologically these genera are similar in pigmentation, excipular construction, and asci, which mostly have terminal opercula and rounded, sometimes forked, bases without croziers. Ascospores have cyanophilic walls or cyanophilic surface ornamentation in the form of ridges or warts. So far as is known the ascospores and the cells of the paraphyses of all species are multinucleate. The six species recognized in these four genera all have limited geographical distributions in the northern hemisphere.     

Respiration and nitrogen excretion of Polinices alderi (Forbes) and Polinices catena (da Costa) (Gastropoda : Naticidae)

Measurements were made of oxygen consumption and NH₃-N excretion, at different temperatures, for two species of gastropod molluscs, Polinices alderi (Forbes) and P. catena (da Costa), preying on bivalve molluscs. Previous observations, for P. alderi, that the rate of oxygen consumption is influenced by diet were confirmed. The effect of temperature on the rates of respiration and excretion was compared for the two species. Oxygen consumption was temperature dependent, with Q₁₀ values of ≈2, in the temperature range 10–20°C, for both species. NH₃-N excretion was relatively insensitive to temperature over the same range. The ratio of oxygen consumed to nitrogen excreted (O:N ratio) was relatively independent of size for both species, but was influenced by diet.     

A survey of alkaloids in the genera Harpalyce and Brongniartia (Fabaceae—Brongniartieae)

The presence of alkaloids in six species of Brongniartia and three species of Harpalyce is reported. This survey revealed remarkable qualitative differences in the alkaloid profiles of these two genera. B. discolor, B. lupinoides, B. sousae and B. intermedia showed a typical -pyridone pattern, with cytisine, anagyrine and baptifoline as major alkaloids. In leaves of the first three species ormosanine-type alkaloids occurred additionally. B. flava and B. vazquezii are devoid of -pyridones, but accumulate lupanine, hydroxylated lupanines and ester alkaloids. All three species of Harpalyce were similar in accumulating -pyridones, but H. formosa differed from H. brasiliana and H. pringlei in the presence of epilupinine. In general the alkaloid profiles of Brongniartia and Harpalyce show similarities to those of the Australian genera Hovea, Lamprolobium, Plagiocarpus and Templetonia and support therefore the actual concept of the enlarged tribe Brongniartieae.     

Enzymes in Schistosoma intercalatum and the relative status of the Lower Guinea and Zaire strains of the parasite

Seven enzyme systems [phosphoglucomutases (PGM), glucose phosphate isomerases (GPI), glucose-6-phosphate dehydrogenases (G6PD), malate dehydrogenases (MDH), laetate dehydrogenases (LDH), acid phosphatases (AcP) and hexokinases] in extracts of adult worms from two isolates of Schistosoma intercalatum, one from Zaire and one from Cameroun, were compared by isoelectric focusing. Two systems (GPI and PGM) were also compared in extracts of cercariae. Distinctive differences between the strains were found in the LDH system and even more marked differences in the G6PD and PGM systems (the latter were apparent in both adult worm and cercarial extracts). These observations are discussed in conjunction with existing evidence on the results of intermediate host infection experiments and of experimental hybridization between the two strains of S. intercalatum. In turn these aspects are discussed in the light of what is known about other species of African Schistosoma. It is concluded that any definite decision on the relative status of the two strains of S. intercalatum is still premature.     

Phylogenetic and biosystematic relationships in four highly disjunct polyploid complexes in the subgenera Ceterach and Phyllitis in Asplenium (Aspleniaceae)

Phylogenetic studies using DNA sequences of two chloroplast regions, rbcL and trnL-F, demonstrate that the proposed genus Ceterach is a small clade within the large genus Asplenium, and sister to the Phyllitis clade. The Ceterach clade is characterised by irregular anastomosing veins and often densely scaled leaf blades. Its taxonomic status as a group nested within Asplenium is confirmed, and it is accepted here as a subgenus with seven species. The Ceterach clade comprises four lineages that correspond to disjunct polyploid complexes: the A. aureum clade forming a polyploid complex (4×, 6×, 8×) in Macaronesia, the A. ceterach clade forming a polyploid complex (2×, 4×, 6×) in the Mediterranean Basin, the A. paucivenosum clade (4×, 6×) in central Asia, and the A. dalhousiae clade (2×) with a disjunct distribution in the Himalaya, Yemen and Eritrea, and southwestern North America. Asplenium paucivenosum is sister to all other members of the Ceterach clade, whereas A. dalhousiae is sister to the A. aureum clade that includes tetraploid A. aureum, hexaploid A. lolegnamense, and octoploid A. parvifolium. Asplenium ceterach and its variations – including the hexaploid A. ceterach subsp. mediterraneum subsp. nov. first described below – form a monophyletic unit, sister to a clade consisting of A. aureum and A. dalhousiae. Asplenium cordatum from Africa and A. haugthonii from the isolated atlantic island of St. Helena are not members of the Ceterach clade, which suggests that leaf blades with dense indumenta have evolved at least twice within asplenioid ferns. The allotetraploid species A. hybridum has the chloroplast DNA from A. ceterach, and therefore the latter species is the maternal ancestor of the former. The other parent of this hybrid species is A. sagittatum that is nested within the sister clade of Ceterach, the Phyllitis clade comprising A. sagittatum and A. scolopendrium. The findings suggest that the current distribution of Ceterach is either the result of long-distance dispersal or represents fragmented relicts of a previously more widely distributed species.     

Phylogenetic reassessment of the Teloschistaceae (lichen-forming Ascomycota, Lecanoromycetes)

The Teloschistaceae is a widespread family with considerable morphological and ecological heterogeneity across genera and species groups. In order to provide a comprehensive molecular phylogeny for this family, phylogenetic analyses were carried out on sequences from the nuclear ribosomal ITS region obtained from 114 individuals that represent virtually all main lineages of Teloschistaceae. Our study confirmed the polyphyly of Caloplaca, Fulgensia and Xanthoria, and revealed that Teloschistes is probably non-monophyletic. We also confirm here that species traditionally included in Caloplaca subgenus Gasparrinia do not form a monophyletic entity. Caloplaca aurantia, C. carphinea and C. saxicola s. str. groups were recovered as monophyletic. The subgenera Caloplaca and Pyrenodesmia were also polyphyletic. In the subgenus Caloplaca, the traditionally recognized C. cerina group was recovered as monophyletic. Because this study is based solely on ITS, to maximize taxon sampling, the inclusion of phylogenetic signal from ambiguously aligned regions in MP (recoded INAASE and arc characters) resulted in the most highly supported phylogenetic reconstruction, compared with Bayesian inference restricted to alignable sites.     

On the embryology and mode of reproduction of selected diploid species of Hieracium s.l. (Asteraceae) from Bulgaria

Three diploid taxa – Hieracium transylvanicum (subgenus Hieracium), Hieracium caespitosum subsp. brevipilum and Hieracium pavichii (subgenus Pilosella) – from five natural Bulgarian populations were investigated embryologically. The peculiarities of the male and female gametophytes, embryo- and endospermogenesis were established in each species. The results suggest that the species propagate sexually as expected from their diploid chromosome number. However, some forms of apomixis have also been observed, e.g. somatic apospory and integumental embryony in H. pavichii. The presence of apomixis in a diploid taxon shows that polyploidy is not an obligatory prerequisite for apomixis and the two phenomena are independent. The embryological plasticity detected in H. pavichii and H. transylvanicum suggests they may have higher opportunities for adaptation and successful reproduction.     

Flavonoids of Astilbe and Rodgersia compared to Aruncus

The flavonoid profiles of Astilbe (four taxa studied) and Rodgersia (two taxa studied) are based on simple flavonol glycosides. Astilbe has 3-O-mono-, 3-O-di-, and 3-O-triglycosides of kaempferol, quercetin, and myricetin, while Rodgersia has only mono- and diglycosides of kaempferol and quercetin. Astilbe×arendsii was also shown to accumulate dihydrochalcone glycosides. The flavonoid profile of Rodgersia is the simplest recorded so far in the herbaceous Saxifragaceae. The flavonoids of two species of Aruncus were shown to be based upon kaempferol and quercetin 3-O-mono- and 3-O-diglycosides. One of the species also exhibited an eriodictyol glycoside. The triglycoside differences were not considered important, but the differences in myricetin occurrences were taken as evidence against derivation of Saxifragaceae from an Aruncus-like ancestor. Should such an event be proposed, however, serious consideration would have to be given to the current pattern of myricetin occurrence in the two families.     

External flavonoid aglycones of Viguiera series Viguiera (asteraceae: heliantheae)

Distribution of external flavonoid aglycones supports other data to suggest that Viguiera series Viguiera (series Dentatae Blake) is a mixed taxonomic grouping. Two species, V. dentata and V. potosina, lack external flavonoid aglycones, whereas the remaining species of the series all produce external flavonoid aglycones and appear to form a natural taxonomic group. The latter group, which consists of species from Baja California and nearby xeric areas, exhibits a diversity of flavonoid types, with different diploid species variously producing flavonols, simple flavones, 6-methoxyflavones, 6-hydroxy,7-methoxyflavones and a chalkone as major compounds. Polyploid species exhibit combinations of flavonoid types from possible diploid ancestors. Compounds of the 6-hydroxy,7-methoxyflavone type appear to characterize the group of species from Baja California and nearby areas within Viguiera.     

Genetic differentiation of two distinct chemotypes of Ferula communis (Apiaceae) in Sardinia (Italy)

The giant fennel, Ferula communis L. (Apiaceae) is a circum-Mediterranean species responsible of severe haemorrhagic intoxication of livestock. Electrophoretic analysis of 14 putative enzyme loci was carried out to assess genetic differentiation among poisonous and non-poisonous chemotypes of F. communis in Sardinia. Genetic structuring characterises all the five populations examined. However, differentiation was higher between poisonous and non-poisonous populations (P<0.00001), and was independent from geographic distances, suggesting a reduced gene flow between the two chemotypes.     

Experimental manipulation of shell color and morphology of the limpets Lottia asmi (Middendorff) and Lottia digitalis (Rathke) (Mollusca: Patellogastropoda)

We experimentally show that substratum can determine an individual patellogastropod's color and morphology. Lottia asmi (Middendorff), previously considered a high-domed, black stenotopic species on trochid gastropods, is similar to other northeastern Pacific limpet species with low profile and tessellated color patterns, when it is translocated to rock substrata. Lottia digitalis (Rathke), a highly variable species with at least two ecological variants that have been considered to be genetically determined, changes between these two forms when translocated from stalked barnacles to rocks. Color changes because the ingested pigments (algal, periostracal, etc.) and other materials (e.g., calcium carbonate) vary between substrata; morphological changes occur as responses to the topographical complexity and constraints of substrata. The geographical distribution of ecological variants of polytypic limpet species, and the ability to achieve cryptic coloration, may be determined by the geographic distributions of algae on which the limpets feed rather than by intrinsic characteristics of the limpets.     

A comparison of reproduction in co-occurring chthamalid barnacles, Chthamalus stellatus (Poli) and Chthamalus montagui Southward

Reproduction in Chthamalus montagui Southward and Chthamalus stellatus (Poli) has been compared along gradients of wave exposure and tidal height. The proportion of barnacles carrying egg masses was greatest at low shore levels in both species, although the difference between levels was more pronounced in C. stellatus. Both species were found to breed between the beginning of May and the end of September. The mean number of broods released per season in both species ranged from 1.0 to 2.1 at high shore levels, from 2.2 to 3.2 at mid shore levels, and from 2.6 to 4.4 at low shore levels. C. stellatus predominated low on the shore at an intermediately exposed site and on the mid and low shore at the most exposed site. At these places it produced more broods per year than C. montagui. Development of the embryos of the two species was complete after 3 wk in vivo at 15°C. Eggs containing embryos of C. stellatus were larger than those of C. montagui, and within each species, larger barnacles produced larger eggs. Egg masses of C. stellanus included more eggs than those of C. montagui. Brood size in both species was greatest in shelter and least in exposure. Egg production was, however, similar in the two species when adjusted for differences in body mass. Egg production per unit body mass was greatest at an intermediately exposed site.