Diversity and distribution of marine Gastrotricha along the northern beaches of the state of São Paulo (Brazil), with description of a new species of Macrodasys (Macrodasyida,Macrodasyidae)

Forty-three putative species were found in this first-ever survey of the marine gastrotrich fauna of Brazil. Samples from 23 locations and 37 sites along the northern coasts of the state of São Paulo yielded 21 species of Macrodasyida (12 genera and five families) and 22 species of Chaetonotida (seven genera and two families). Based on morphology, 26 species appear to be taxa not previously described and thus far endemic to Brazil, 13 are known species, while one in each of the genera Diplodasys, Paradasys and Tetranchyroderma remains undetermined. The overall high diversity contrasts with the generally low number of species from single locations, averaging 4.3 (SD 3.5) spp. per location; very few species were found in sites characterized by very fine sand sediment loaded with detritus and by high water turbidity (e.g. 1 sp. in praia da Fazenda), whereas a well-diversified gastrotrich community was found in localities characterized by medium or fine sand with little detritus and clear water (e.g. 14 spp. in praia de Castelhanos). The macrodasyidans, Paraturbanella sp. 1, Pseudostomella sp. 1 and Tetranchyroderma sp. 1, and the chaetonotidan Heteroxenotrichula sp. 1 were the most common species, often sympatric and particularly frequent and abundant along the continental shoreline (recorded in 50–65% of these localities); on the other hand, Macrodasys fornerise n. sp., Ptychostomella sp. 1, Tetranchyroderma sp. 3 and Thaumastoderma sp. 2, while occurring sometimes in very high numbers, exhibited a much narrower range, being encountered only once or twice during the survey. The main morphometric traits are described of the 13 species considered to be cosmopolitan or with at least an amphi-Atlantic distribution, including Chaetonotus apechochaetus and Halichaetonotus marivagus, reported here for the first time from the Americas; of the 26 species thus far endemic to Brazil, Macrodasys fornerise n. sp., which is characterized by a noticeable 145?µm-long frontal organ, is also described and figured.     

Ecological distribution and reproductive period of the hermit crab Loxopagurus loxochelis (Anomura,Diogenidae) on the northern coast of São Paulo State,Brazil

The present study aimed to determine the ecological distribution of Loxopagurus loxochelis as a function of selected environmental factors, as well as its reproductive period based on the combined analysis of the presence of ovigerous females and the development of the gonad. The collections were carried out monthly from January to December 2000 in the region of Ubatuba (SP), using a fishing boat equipped with two double rig nets, in isobaths of 5, 10, 15, 20, 25, 30, 35 and 40?m, at which depths samples of sediment and water were collected. The cephalothoracic shield length and sex of the animals were determined; the abdomen was dissected to verify gonad development stages. A total of 334 individuals was obtained (196 males, 48 ovigerous females and 90 non-ovigerous females) with sizes varying from 3.0 to 8.6?mm (5.7±1.0?mm). A greater abundance of L. loxochelis (95.2%) was observed at depths of 20 and 25?m. These sites mainly revealed a substratum stable with a very fine sand fraction, which facilitates the habit of embedding shown by this hermit. With regard to gonadal analysis, it was possible to classify four gonad development stages for each sex: immature, rudimentary, developing and developed. It was observed that in the winter months about 71% of the females had gonads either developing or developed and 67% were ovigerous. Therefore, the winter period can be considered the peak of reproduction for this species, characterizing a typical seasonal-continuous reproduction.     

Ectosymbionts of the non‐indigenous Asian shore crab,Hemigrapsus sanguineus (Decapoda: Varunidae), in the western north Atlantic,and a search for its parasites

Over 560 Asian shore crabs, Hemigrapsus sanguineus, collected mainly in the spring of 2005 and 2006 from rocky intertidal locations in southern New Jersey, were examined for epibionts. Small numbers of the sympatric green crab, Carcinus maenas, and the Atlantic mud crab, Panopeus herbstii, were examined for epifauna to compare with H. sanguineus. Blue mussel spat, Mytilus edulis, and the encrusting, cheilostome bryozoan, Conopeum tenuissimum, were the dominant ectosymbionts of the shore crab, with prevalences of 22.2 and 32.1%, respectively; ranges of intensity were 1–146 spat/crab and 1–31 colonies/crab. Both species are incidental symbionts. Larger crabs had higher prevalences and intensities of C. tenuissimum colonies, and these colonies displayed a distinct pattern of attachment to the carapace which seemed to be related to crab morphology and habitat. Much less common was the encrusting, ctenostome bryozoan Alcyonidium albescens, a facultative symbiont species with a prevalence of 3.4%. Other epibionts were the encrusting, cheilostome Membranipora tenuis, the tubicolous polychaetes Hydroides dianthus, Sabellaria vulgaris, and Spirorbis sp., the barnacles Balanus improvisus and Semibalanus balanoides, and unidentified thecate hydroids, all incidental symbionts with prevalences from 0.2 to 3.2%. The total number of known ectosymbionts of H. sanguineus, including additional species found previously in the USA and the western Pacific, is 13. Carcinus maenas and P. herbstii share some of the same symbionts. Rhizocephalan externae were not observed in any of the crab species used in this study, nor were gill parasites or internal parasites found among 248 specimens of H. sanguineus.     

Along‐ and across‐shore components of the spatial distribution of the clam Tivela mactroides (Born, 1778) (Bivalvia,Veneridae)

Beach clam fisheries often provide an alternate income for traditional fishermen, but this activity is highly vulnerable to urbanization of coastal areas. Tivela mactroides is a beach clam commonly harvested in the Caribbean (Venezuela) and on the south‐eastern Brazilian coast. Only localized records on its spatial structure in size and abundance are available to support management of this clam. The present study showed that the spatial distribution in abundance and size of T. mactroides in Caraguatatuba Bay, state of São Paulo, Brazil, has both along‐ and across‐shore (intertidal and subtidal) components. The nature of this distribution should be taken into account in the design of further population or monitoring studies concerning this species. Clam density varied along‐shore, with a tendency towards higher numbers of individuals in the stations near the northern side of river mouths of this bay. Lower densities were related to the occurrence of sea‐stars and sand‐dollars. The intertidal and subtidal across‐shore distribution of clam abundance and size varied between and within areas (southern and northern). The individuals from the southern area were concentrated at intermediate tidal levels (0.2–0.6 m in relation to mean low water), whereas in the northern area the clams were more homogeneously distributed. The uppermost limit of their distribution was 0.8 m (southern) and 0.4 m (northern), and an upwards tendency towards increased size was more evident in the northern area. In the subtidal, abundance and individual size tended to increase from the deepest (4.5 m) to the shallowest (0.5 m) levels only in the southern area. Individual clams in the northern area tended to be smaller and more abundant than in the southern area. The species had an ontogenic distribution: small‐sized individuals were recorded only in the subtidal. Possible causes for these patterns and for the differences between areas (human exploitation, organic pollution, beach morphodynamics, differential recruitment, and adult–larvae interactions) are discussed, and specific studies are suggested to evaluate formally the proposed hypotheses.     

Reflection of the Neogene–Quaternary phylogeography in the recent distribution limiting climatic factors of eight Mediterranean Phlebotomus species (Diptera: Psychodidae)

The diversification of Mediterranean Phlebotomus species occurred during the Neogene and Quaternary periods. The climatic and geographical history of the Mediterranean area plausibly influenced the climatic requirements of recent sand fly species. Our aim was to investigate the European zoogeography and the climate-based ecological groups of eight Phlebotomus species considering the phylogeography of the studied taxa. Jaccard index calculation, hierarchical cluster and principal component analyses were performed. The results of Jaccard-coefficient calculations may indirectly refer to the former existence of three possible glacial refuges of sand fly populations in Europe: an Iberian, an Apennine and a Balkan Peninsula–Asia Minor refuge. Three main climatic groups of the studied sand fly species were distinguished, namely the so-called ‘Trans-Mediterranean’, ‘East Mediterranean’ and ‘West Mediterranean’ groups. Our results suggest that the ancestor of Phlebotomus similis and Phlebotomus sergenti was adapted to the hot, dry summer Mediterranean climate during the late Neogene. The third member of this climate group, Phlebotomus papatasi because of co-adaptation shows similar climatic requirements as P. similis and P. sergenti. The five Larroussius species studied should have evolved under moister climatic conditions. Species of the ‘West Mediterranean’ group were adapted to the milder and wetter oceanic climate of Atlantic coasts. The species of the ‘East Mediterranean’ group diversified under the less balanced climate of the East Mediterranean. The recent climatic requirements and the European distribution of the studied species is the consequence of the complex Quaternary–Neogene geographical and climatic history of their former habitats in the Old continent. The adaptation of the ancestors of the studied sand fly species to the changing geographical and climatic factors of Europe are discussed.     

Geographical variation in the golden‐striped salamander,Chioglossa lusitanica Bocage, 1864 and the description of a newly recognized subspecies

Morphological and genetic data for the Iberian golden‐striped salamander, Chioglossa lusitanica, demonstrate the existence of two groups with southern and northern ranges, connected by a zone of intergradation in central Portugal. Because reproductive isolation between them is incomplete we consider the groups to be subspecies. The type locality of C. lusitanica (Buçaco near Lousã) is situated inside the mixed zone. This necessitates identification of the nominotypical subspecies. We sequenced a fragment of mitochondrial DNA from one of the species' syntypes and we determined what position over a latitudinal transect maximizes the morphological discrimination between the groups. Both approaches indicate that C. lusitanica from Buçaco represents the southern subspecies. A new subspecies of C. lusitanica is described from a northern locality (Valongo near Porto in north‐western Portugal). A lectotype is designated for Chioglossa lusitanica.     

Comparisons of the alpine bird communities across habitats and between autumn and winter in the mid‐Yalong Zangbo River valley,Tibet

The extreme alpine environment around the mid‐Yalong Zangbo River on the Tibetan plateau supports a unique avifauna. To understand the structure and habitat selection of this poorly known bird assemblage, we quantified abundance of the birds in four representative types of vegetation and a human settlement inside a shrub‐covered alpine valley (29°27′N, 91°40′E, 4000–5200 m a.s.l.) in the Lhasa mountains, Tibet, from September 2004 to January 2005. A total of 40 species of birds was recorded, six of which were summer breeders, one vagrant autumn migrant, 29 permanent residents, and four local wintering migrants. Latitudinally migrating taxa were absent. Of the 33 wintering species, 70% were alpine specialists. Patterns of distribution of species and individuals differed across habitats. The highest bird species richness was found in Rose–Barberry shrub where vegetation was most complex, and fruiting and seeding plants abundant. From autumn to winter, birds tended to aggregate in the human settlement for foods supplemented by local Buddhists; as a consequence this habitat contained the highest individual density. In terms of trophic guilds, plant‐eating birds were predominant in composition (65.8–75.8%) and numerically abundant (89.8–96.7%) in all the habitats. We concluded that vegetation diversity and food supply significantly influence species composition and individual abundance of the alpine bird community. For long‐term survival of the unique bird assemblage, we argue for protection of the shrub vegetation as it is difficult to regenerate in the harsh high‐altitude conditions.     

Growth rates of wild green turtles,Chelonia mydas,at a temperate foraging habitat in the northern Gulf of Mexico: assessing short‐term effects of cold‐stunning on growth

There are multiple factors that may determine individual and population growth rates and understanding the impact of extrinsic factors, such as temperature, is important for successful recovery plan stock assessment and modelling. In January 2001 and January 2003, cold‐stunning events occurred along the northern Gulf of Mexico, in St Joseph Bay, Florida. In this study we examine the short‐term effects of decreased water temperatures and repeated cold‐stunning events on the growth of juvenile green turtles in northwest Florida. There were no significant effects of number of cold‐stunning events on growth, although turtles stunned twice tended to grow slower than non‐stunned turtles. This is the first study to provide information on the growth rates of green turtles in the northern Gulf of Mexico and it is the first examination of the effects of cold‐stunning on growth in any sea turtle population.