Relationships between length and weight of freshwater macroinvertebrates in Japan

Relationships between weight (W; dry weight) and length (L; head capsule width, total body length or head carapace length) were examined in 31 Japanese freshwater macroinvertebrate taxa, using the form W = aL ^b . The relationships were expressed as data of the lowest taxonomic level and data of higher taxonomic levels. The length–weight relationships obtained in this study were similar to those obtained in North America and Europe at the lowest taxonomic level, whereas they could be different from those obtained in North America and Europe at the higher taxonomic levels. We suggest that researchers should make their own regressions for a target taxon or use the regression for the same taxon as possible lower taxonomic level in the local area.     

Multiple reproductive strategies of a spring ephemeral plant,Fritillaria maximowiczii,enable its adaptation to harsh environments

Spring ephemeral plants that experience harsh environments have developed specific reproductive characteristics. These characteristics are of great importance to the survival and reproduction of these species, particularly for rare and endangered plants. Fritillaria is a genus consisting of spring ephemeral plants with significant medicinal and ornamental value whose wild resources are highly threatened and whose reproductive characteristics and adaptative evolutionary mechanisms are still not well understood. Fritillaria maximowiczii is positioned at the most basal clade on the Fritillaria phylogenetic tree, whose reproductive characteristics remain obscure. In this study, we report the flowering dynamics, pollination biology and breeding system of F. maximowiczii. The flowering process of F. maximowiczii can be divided into seven stages. Based on the pollen/ovule ratio, the outcrossing index and a field pollination experiment on a natural population, F. maximowiczii showed high levels of outcrossing and self-compatibility. Three types of pollinators were observed: two kinds of bumblebees, and spiders. Diverse herkogamy and dichogamy may have considerably improved its reproductive success rate. Furthermore, a special reproductive mode not previously reported in wild populations of Fritillaria, apomixis, was strongly suspected based on a high fruit setting rate (36.84%). Our study suggests F. maximowiczii has developed multiple reproductive strategies to adapt to harsh environments and ensure population reproduction, and the diverse reproductive mechanisms may be related to its primitive phylogenetic position in the genus. This study not only broadens our understanding of mechanisms of ecological adaptation in spring ephemeral plants but also provides key data for the conservation of Fritillaria.     

Comparative morphology of the leaf epidermis in Fritillaria (Liliaceae) from China

The leaf epidermis of 16 species and one putative species of Fritillaria was examined using light microscopy (LM) and scanning electron microscopy (SEM). The results showed that the stomatal and other epidermal features were constant within species. Epidermal cells of Fritillaria under LM were usually polygonal and anticlinal cell walls were straight or curved. In a few species they were irregular, with sinuous anticlinal cell walls. The cuticular membrane of Fritillaria was usually striated, and the wax ornamentations were flaked, granular or concomitant. Based on leaf epidermal characteristics, the subdivision of Fritillaria is discussed, and the statistical t‐test method was used to ascertain the significance level of the differences in the stomata of each species. All orientations of the stomatal poles in Fritillaria were the same, and this phenomenon was named ‘stomatal orientation’. The stomatal characteristics support the origin of section Fritillaria in China from two floristic elements. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 93–109.     

Habitat segregation and genetic relationship of two heptageniid mayflies, <Emphasis Type="Italic">Epeorus latifolium</Emphasis> and <Emphasis Type="Italic">Epeorus l-nigrus</Emphasis>, in the Shinano-gawa River basin

The heptageniid mayflies Epeorus latifolium and Epeorus l-nigrus are often the dominant species in the upper and midstream areas of Japanese rivers; as such, they play a significant role in river ecosystems. However, although these two species have been identified using the morphological characteristics of the male in its adult stage, it is impossible to differentiate them in their nymphal stage. We conducted a study to elucidate their distribution pattern, i.e., the current distribution of these two species in the Shinano-gawa River basin, based on quantitative field sampling and genetic analysis of nymphs and also some male adults; for these, it was possible to differentiate between the two species reliably. The data collected from the 30 study sites of the 1-year-long study revealed that the E. latifolium and/or E. l-nigrus mayflies are clearly distributed over a very broad area, and they appeared to be the dominant species at about a third of the study sites. Based on our genetic analysis, including several male adult specimens of E. latifolium and E. l-nigrus, it was clearly revealed that E. latifolium and E. l-nigrus respectively form two separate monophyletic clades. That is, E. latifolium and E. l-nigrus are clearly genetically differentiated, and they are considered to each represent a discrete species. Then, we plotted the collection sites of reliably identified specimens of E. latifolium and E. l-nigrus on the Shinano-gawa River basin map. This resultant map clearly displays that E. latifolium is distributed in the upper stream area rather than E. l-nigrus. To conclude, a pronounced ‘habitat segregation’ or ‘current distribution’ is clearly observable.     

George Murray,naturalist

Summary

The distributions of the British taxa within the genus Gentianella are examined. They form a remarkably complete picture of the whole of the section Endotricha throughout its range. Only one species, G. amarella, seems not to be seriously diminishing but it, in common with the others, is ecologically inflexible and has been badly affected by the activities of man (and the loss of the rabbit). Direct environmental changes may be responsible, too, for the disappearance of G. campestris from many places. Some names, notably G. baltica, have gone because of changes in taxonomic thinking, or taxonomic fashion; the criteria by which they were established can now be seen as the results of relatively short term changes, and we can better deal with them as biosystematic units within a wider taxonomic species. Others (G. germanica, G. uliginosa and G. cornubiensis), are the victims of environmental change in a less direct way; the breakdown of breeding barriers leads to their reabsorption into the wider ranging species. So the losses are both apparent and real. Although the gene-pool of G. amarella the ‘polyspecies’ is perhaps enlarging it does not equip it to resist the erosion of its habitats. G. campestris may have already gone too far along the same road.     

Petal: a reliable explant for direct bulblet regeneration of endangered wild populations of <Emphasis Type="Italic">Fritillaria imperialis</Emphasis> L.

Wild populations of Fritillaria imperialis L. are facing extinction and need urgent conservation. This paper presents an efficient system for in vitro direct bulblet regeneration of these populations by petal culturing of flower buds. Petals at different developmental stages, green-closed flower bud (before nectar secretion) and red-closed flower bud (beginning of nectar secretion), were used as explants, and the effects of various proportions of cytokinin to auxin on direct bulblet regeneration pathway were evaluated. More explants switched on direct regeneration pathway in combination of auxins (0.6 mg l⁻¹ NAA + 0.4 mg l⁻¹ IAA) with higher level of cytokinin (1 mg l⁻¹ BAP). In contrast, auxins (0.6 mg l⁻¹ NAA + 0.4 mg l⁻¹ IAA) with lower level of cytokinin (0.1 mg l⁻¹ BAP) produced more bulblets per regenerated explant. In green-closed flower bud stage, direct bulblets regenerated from the end of petal where it was connected to the receptacle, while nectar secretion site was the place of bulblet formation in red-closed flower bud stage. In addition, genotype-dependency of direct bulblet regeneration pathway was investigated by using two different wild populations of Fritillaria imperialis. This plant regeneration procedure was applicable to different Fritillaria genotypes and regenerated bulblets were normal.     

Microhabitat and morphometric variation in two species of <Emphasis Type="Italic">Prasiola</Emphasis> (Prasiolales,Chlorophyta) from streams in central Mexico

Prasiolales are characterized by high morphological plasticity. This problem in taxonomic delimitation of the species may be a result of environment heterogeneity. Habitat characteristics and morphological variation of P. mexicana and P. nevadensis, two species of freshwater leaf-like thallus green algae, were investigated in five sites in central México where the morphological traits of these species overlap. Comparisons were made between habitat characteristics among streams and transects with and without Prasiola samples. Although no consistent correlation was found between environmental variables and morphological traits, a significantly wider range of habitat characteristics of current velocity and irradiance and morphometric variation (lamina length, lamina diameter, cell length, surface of the thallus, thickness and number of layers) suggested that P. mexicana was more plastic than P. nevadensis in its physicochemical requirements. Our results suggest that small variation of microhabitat conditions in P. nevadensis (irradiance and current velocity) could explain its very restricted geographic range in streams in central Mexico.     

A study of genetic variations,population size,and population dynamics of the catadromous Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis> (Pisces) in northern Taiwan

Japanese eels are widely distributed in northeast Asian countries, and they have a catadromous life history. In this article, we explored whether Japanese elvers have temporal genetic structure and whether the population went through population expansion during the Pleistocene. In total, 273 specimens were collected from the Tanshui River estuary, northern Taiwan, in 1989–2008. The highly variable region of the mitochondrial DNA D-loop was cloned and sequenced. A genealogy was reconstructed based on the Neighbor-joining method, and results showed an unobvious yearly clade and a high level of haplotype diversity, but low mean nucleotide diversity among samples. Most of the pairwise F _ST appeared statistically insignificant. These genetic parameters suggested a lack of temporal population structure combined with a sustainable high effective population size of Japanese eels. Negative values of Tajima’s D and Fu’s F _s appeared in all samples with high significance. The mismatch distribution, skyline plot, and minimum spanning network indicated that historical population expansion of the Japanese eel could be traced back to the Pleistocene. Results of this study imply the Japanese eel has a complex life history, and the temporal structure of Japanese eels should be continually monitored in the future.     

New reconstruction of <Emphasis Type="Italic">Kimberella</Emphasis>, problematic Vendian metazoan

Six groups of fossil remains of Kimberella quadrata are described. They represent the imprints of the body in different types of preservation (including the group of specimens that are elongated more than twice in comparison with the common ones) and also the feeding traces and mucus secretions. The imprint is considered to be created only by the upper side of the body. The fossil material shows that Kimberella had hard sclerites, probably of aragonite, and several teeth in its mouth. Kimberella is suggested to have “the mantle” with sclerites, wider foot, which was spread over the outer surface of the mantle, and the strong transverse and longitudinal musculature.     

A study of hybrids between betula pubescens Ehrh. and Betula nana L. from Sutherland—an integrated approach

Summary

Ben Loyal, Sutherland is one of the two sites in Britain where hybrids between Betula pubescens Ehrh. and Betula nana L. have been reported. In view of the confused taxonomic state of the genus Betula, populations in the area were surveyed for distinguishing characteristics of both parents and possible hybrids. Individual plants were investigated by an integration of morphological, biochemical and cytological techniques. The approach and results are considered significant in the wider context of taxonomic study in the genus Betula.     

Mitochondrial cytochrome <Emphasis Type="Italic">b</Emphasis> sequences resolve the taxonomy of field mice (<Emphasis Type="Italic">Apodemus</Emphasis>) in the western Balkan refugium

Apodemus sylvaticus stankovici, described from the topographically rough landscape of the western Balkan glacial refugium, was recently proposed as being either a junior synonym of Apodemus flavicollis or a species on its own right. To untangle this taxonomic vagueness, we sequenced complete cytochrome b gene in 28 field mice collected at 12 locations in the mountains of Bosnia and Herzegovina, Montenegro, western Macedonia and northern Greece. Samples yielded 27 new haplotypes which clustered into two distinct groups. One of these clades also included the reference haplotype of A. flavicollis, while another cluster emerged as being identical with the reference sample for A. sylvaticus. As is common in Apodemus, both species retrieved in our analysis were characterized by low levels of intraspecific variation (0.4–0.9%) as opposed to a high level of differentiation between them (8.0–10.0%); therefore, the taxonomic classification of our material was without doubt. We found no evidence regarding the presence of an additional cryptic species in the mountains of the western Balkans. The very similar values of genetic variability in the two species imply their common evolutionary history of a long-term coexistence in the western Balkan refugium.     

Skull variation in the Siberian roe deer <Emphasis Type="Italic">Capreolus pygargus</Emphasis> from the Far East: a revision of the distribution of the subspecies

Extremely widespread in the Palaearctic, roe deer are heterogeneous in many ways including their morphology. At present, two roe deer species and four basic subspecies are acknowledged. The taxonomic system of the Siberian roe deer is poorly developed compared to that of the European roe deer. One of the principal points of roe deer systematics is the determination of the boundaries of the ranges of the roe deer subspecies requiring a thorough study of the species’ diversity. By using craniometry, one of the most adequate systematics techniques, we have analyzed geographical distribution of the Suberian roe deer in the Russian Far East and adjacent areas. All studied specimens were separated into three groups, the distributions of craniometric parameters of two of which did not overlap. One of the groups corresponds to Capreolus pygargus pygargus Pallas, 1771, while the other two do not correspond to any of the Siberian roe deer subspecies presently acknowledged. We have shown that the C. pygargus pygargus range extends to the east to the Northern Primorye, i.e., it is 2,000 to 3,000 km wider than previously believed. The subspecies status of Capreolus pygargus tianschanicus Satunin, 1906 was not confirmed. The Southern Primorye and left bank of the Amur River are thus a part of the range of Capreolus pygargus melanotis Miller, 1911, penetrating here from the Northeastern China.     

Exploring the potential of clay in mitigating <Emphasis Type="Italic">Pyrodinium bahamense</Emphasis> var. <Emphasis Type="Italic">compressum</Emphasis> and other harmful algal species in the Philippines

Harmful algal bloom occurrences worldwide have prompted the testing and use of methods to control and mitigate their detrimental effects. This study investigates the potential of Philippine clay minerals to physically remove phytoplankton cells under laboratory conditions. Ball clay had the highest removal efficiency (∼95%) for Pyrodinium bahamense (paralytic shellfish poisoning causative organism) cells. A slight decrease in the efficiency by 10–20% was seen when culture volume was increased from 50 mL to 1 L. Removal efficiency was reduced to ∼95% when water motion was introduced. Removal of other phytoplankton species (Gymnodinium sanguineum, Amphidinium carterae, Pyrophacus horologium, Chatonella marina, and Alexandrium sp.) using ball clay was less efficient (<70%). Cell removal efficiencies differed with phytoplankton species belonging to the same taxonomic group. Possible mechanisms for cell removal are described.     

Species delimitation in sharpnose sharks (genus <Emphasis Type="Italic">Rhizoprionodon</Emphasis>) in the western Atlantic Ocean using mitochondrial DNA

Despite Springer’s (1964) revision of the sharpnose sharks (genus Rhizoprionodon), the taxonomic definition and ranges of Rhizoprionodon in the western Atlantic Ocean remains problematic. In particular, the distinction between Rhizoprionodon terraenovae and R. porosus, and the occurrence of R. terraenovae in South American waters are unresolved issues involving common and ecologically important species in need of fishery management in Caribbean and southwest Atlantic waters. In recent years, molecular markers have been used as efficient tools for the detection of cryptic species and to address controversial taxonomic issues. In this study 415 samples of the genus Rhizoprionodon captured in the western Atlantic Ocean from Florida to southern Brazil were examined for sequences of the COI gene and the D-loop and evaluated for nucleotide differences. The results on nucleotide composition, AMOVA tests, and relationship distances using Bayesian-likelihood method and haplotypes network, corroborates Springer’s (1964) morphometric and meristic finding and provide strong evidence that supports consideration of R. terraenovae and R. porosus as distinct species.     

Plastid‐encoded rbcL phylogeny suggests widespread distribution of Galdieria phlegrea (Cyanidiophyceae,Rhodophyta)

The rare microscopic red alga Galdieria phlegrea (Cyanidiohyceae, Rhodophyta) has been discovered in the extremely acid Tinto River in Spain and this occurrence is here related to previous knowledge about the distribution and ecology of this enigmatic alga. The taxonomic affiliation of the new isolate of G. phlegrea was revealed by reconstructing the phylogeny of plastid‐encoded rbcL. According to this phylogeny, the Tinto River alga is closely related to other G. phlegrea strains originating from extreme habitats in Czechia, Italy and Turkey, suggesting a wider distribution and higher ecological versatility than previously thought. The results suggest that G. phlegrea, and then possibly also other cyanidiophycean algae, are not as restricted to strongly acidic and hot microhabitats as previously believed, which, in turn, may indicate that they may commonly have been overlooked and possibly are much more widespread than is currently believed.     

Morphological and genetic study of Prorocentrum donghaiense Lu from the East China Sea, and comparison with some related Prorocentrum species

In this paper, the detailed morphology of Prorocentrum donghaiense Lu from both field samples and cultures was examined, and a taxonomic comparison was made between P. donghaiense and some related Prorocentrum spp. using morphological and molecular data and other published information. There were distinct differences among these species in morphological characteristics that historically have been presented as conservative features. The discrepancies extended beyond that of individual variations within the same species due to environmental factors. Therefore, these morphological features may not be conservative but, rather, polymorphic depending on environmental conditions. Based on this analysis, we suggest that the high-biomass bloom-forming species in the East China Sea, previously reported as Prorocentrum dentatum Stein, is P. donghaiense Lu. The species reported from the East China Sea and Japanese and Korean waters appear to be the same species. Molecular data also suggest that P. dentatum (CCMP1517) and P. donghaiense are genetically identical. Therefore, the geographic distribution of P. donghaiense may be much wider than expected.