Effects of fluctuating temperature and immersion on asexual reproduction in the intertidal sea anemone Hauplanella luciae (Verrill) in laboratory culture

Haliplanella luciae (Verrill) was maintained in laboratory cultures according to a 2 × 2 factorial design. The factors were 1) constant immersion or continuously alternating periods of 6 h immersion followed by 6 h emersion and 2) 18 °C constant temperature or 24 °C during one 6-h emersion period each day and 18 °C for the remaining 18 h. Significantly different numbers of fissions were observed between both the two immersion and two temperature conditions. A negative correlation was found between the number of fissions and the total dry weight of tissue per bowl. There was a different distribution of individual weights in the two immersion conditions. Some instances of pedal laceration were observed.     

Dynamic tuning of hair bundle mechanoreceptors in a sea anemone during predation

The sea anemone Haliplanella luciae (Cnidaria, Anthozoa) detects chemical and mechanical stimuli from prey. Hair bundle mechanoreceptors on the tentacles participate in regulating discharge of microbasic p-mastigophore nematocysts. Properly stimulated hair bundles sensitize the anemone to discharge nematocysts into objects that contact the tentacles. The hair bundle mechanoreceptors are composed of stereocilia derived from a multicellular complex. This complex consists of a single sensory neuron surrounded by two to four supporting cells. The mechanoreceptor is similar in many ways to vertebrate hair cells of the acousticolateralis system. However, anemone hair bundles are adjustable in structure and responsiveness according to the activity of two different chemoreceptors. One chemoreceptor binds N -acetylated sugars and the other binds amino compounds including proline. N -acetylated sugars induce lengthening of the hair bundle and a downward shift in frequencies that elicit maximal discharge of microbasic p-mastigophore nematocysts. Furthermore, N -acetylated sugars shift maximal discharge to smaller amplitude vibrations. Thus, N -acetylated sugars likely tune hair bundles so that small, swimming zooplankton stimulate maximal discharge. Proline leaks into the seawater from the hemolymph of wounded prey. Proline induces shortening of the hair bundle and shifts maximal discharge of nematocysts to higher frequencies and to larger amplitude vibrations. Thus, proline likely tunes hair bundles so that small, wounded, prey stimulate maximal discharge of nematocysts as they struggle to escape. Thus, suitably sized prey stimulate maximal discharge of microbasic p-mastigophore nematocysts upon first contacting the anemone tentacle and again upon attempting to escape.     

Asexual Reproduction, Population Structure, and Genotype-Environment Interactions in Sea Anemones

Our studies of sea anemones reveal that asexual reproductioncan lead to the amplification of particularly successful genotypesPopulations of Haliplanella luciae studied to date are characterizedbv exclusively asexual reproduction and typically are dominatedby one or a few clones A field translocation experiment suggeststhat this population structure may result from differentialmortality among colonizing clones most of which are not preadaptedto local conditions Asexual reproduction by survivors leadsto extensive multiplication of one or a few genotypes Metridiumsenile reproduces sexually and asexually and we ofler evidencethat there is significantly less vegetative proliferation butlarger individual body size in areas of low tidal current velocitythan in areas of moderate to high velocities This may indicatethat small individuals (produced asexually) are at a particularfeeding disadvantage in slowly moving water leading to an emphasison maintaining individual body sizeat the expenseol asexualleproduction Individuals heterozygous fora phosphoglucose isomerase(PG1) locus appear to be more successful than homozygotes inmaximizing body size independent of current regime and in maintaininglarge clone biomass in low velocity habitat Members of heterozygoteclones are significantly more dispeised some clonemates beingseparated by 9 meters or more and are overrepresented in thelow velocity habitat Selection against (small) homozygotes activechoice of habitat, and passive differential dispersal of larvaeand adult anemones may all contribute to this pattern.     

Evidence for involvement of TRPA1 in the detection of vibrations by hair bundle mechanoreceptors in sea anemones

A homolog of TRPA1 was identified in the genome of the anemone, Nematostella vectensis (nv-TRPA1a), and predicted to possess six ankyrin repeat domains at the N-terminus and an ion channel domain near the C-terminus. Transmembrane segments of the ion channel domain are well conserved among several known TRPA1 polypeptides. Inhibitors of TRPA1 including ruthenium red decrease vibration-dependent discharge of nematocysts in N. vectensis and Haliplanella luciae. Activators of TRPA1 including URB-597 and polygodial increase nematocyst discharge in the absence of vibrations. Co-immunoprecipitation yields a band on SDS-PAGE gels at the predicted mass of the nv-TRPA1a polypeptide among other bands. Co-immunoprecipitation performed in the presence of antigenic peptide decreases the yield of this and several other polypeptides. In untreated controls, anti-nv-TRPA1a primarily labels the base of the hair bundle with some labeling also distributed along the length of stereocilia. Tissue immunolabeled in the presence of the antigenic peptide exhibits reduced labeling. Activating chemoreceptors for N-acetylated sugars induce immunolabel to distribute distally in stereocilia. In anemones, activating chemoreceptors for N-acetylated sugars induce hair bundles to elongate among several other structural and functional changes. Taken together, these results are consistent with the possibility that nv-TRPA1a participates in signal transduction of anemone hair bundles.     

First record of the sea anemone Diadumene lineata (Verrill 1871) associated to Spartina alterniflora roots and stems, in marshes at the Bahia Blanca estuary, Argentina

We report the occurrence of the orange-striped green anemone Diadumene lineata (Verrill 1871) (=Haliplanella lineata) in salt marshes at the Bahía Blanca Estuary for the first time in August 2005. We also found this species attached to roots and stems of Spartina alterniflora, an association that has never been registered before. After their determination, sampling was performed during a year to evaluate seasonal abundance of this sea anemone. Results showed that D. lineata was present through the whole year, indicating the existence of a stable population. All individuals sampled were found attached to roots or stems of S. alterniflora, with the higher abundances detected in summer. Further studies are necessary to precise the potential effects of this exotic sea anemone on salt marsh communities.     

Ticks species (Ixodida) in the Summit Municipal Park and adjacent areas,Panama City,Panama

From September 2007 to September 2009, we studied the species of ticks present in the Summit Municipal Park. Ticks were extracted from zoo animals, free-living wild mammals and reptiles trapped, dead mammals on the roads and environment (ground and zoo burrows). A total of 2,649 ticks were collected: 2,167 immature stages (1,345 larvae and 822 nymphs) and 482 adults. Seventeen species were identified: Ornithodoros puertorricensis (Argasidae), Amblyomma auricularium, A. cajennense, A. calcaratum, A. dissimile, A. geayi, A. naponense, A. nodosum, A. oblongoguttatum, A. ovale, A. pecarium, A. sabanerae, A. tapirellum, A. varium, Ixodes luciae, Haemaphysalis juxtakochi and Rhipicephalus sanguineus (Ixodidae), representing 36% of the species reported in Panama. Amblyomma ovale was the species most commonly infesting animals from the zoo.     

Taxonomy,phylogeny, and diversity of the extinct Lesser Antillean rice rats (Sigmodontinae: Oryzomyini), with description of a new genus and species

Rice rats (Sigmodontinae: Oryzomyini) are abundant in the Late Quaternary fossil record and in Holocene pre‐Columbian archaeological middens across the Lesser Antilles. All of these rice rats are now extinct, and their regional diversity and systematics remain extremely poorly understood. We redescribe all of the region's rice rat taxa known from adequate diagnostic material (Megalomys desmarestii, Megalomys luciae, and Oligoryzomys victus), and describe a new genus and species, Pennatomys nivalis gen. et sp. nov. , from archaeological sites on St. Eustatius, St. Kitts, and Nevis, which formed a single larger island during Quaternary low sea‐level stands. Cladistic analysis supports the inclusion of O. victus within Oligoryzomys, and identifies Megalomys as a sister group of the large‐bodied genera Sigmodontomys or Sigmodontomys + Nectomys, suggesting that large body size in Megalomys represents phyletic gigantism rather than ‘island gigantism’. Megalomys and Pennatomys belong to an oryzomyine clade that has undergone remarkable radiation throughout the oceanic and continental‐shelf islands of the Neotropical region, but these genera do not represent a monophyletic group within the Nectomys subclade, indicating multiple over‐water colonization events of the Lesser Antillean island chain. Although Lesser Antillean rice rats were heavily exploited by prehistoric Amerindians, it is likely that most or all of these taxa survived until European arrival in the region. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 748–772.     

The impact of introduced ship rats (Rattus rattus) on seedling recruitment and distribution of a subantarctic megaherb (Pleurophyllum hookeri)

Abstract The impact of introduced ship rats (Rattus rattus) on recruitment of the megaherb Pleurophyllum hookeri Buchan. (Asteraceae) was examined on subantarctic Macquarie Island, an island with no extant native terrestrial vertebrates. Pleurophyllum hookeri (Asteraceae) forms a dominant component of the Macquarie Island vegetation and is restricted to the subantarctic. The Macquarie Island population of P. hookeri is the most extensive and intact. Introduced ship rats (Rattus rattus) are well established in tall tussock grassland of Macquarie Island. We detected rat activity for the first time within P. hookeri herbfields, in autumn 2000. We found rats were destroying up to 90% of racemes. By excluding rats from caches of inflorescences that they had formed, we found they were having a significant negative effect on initial recruitment and seedling survival within the caches. However, because of high seedling mortality after 1 year, there was no sustained impact of the exclosures on P. hookeri seedling density.     

A novel statistical analysis of cnidocysts in acontiarian sea anemones (Cnidaria, Actiniaria) using generalized linear models with gamma errors

Comparative studies on cnidocysts, involving adequate statistical treatment, are very scarce. Classical statistical tests are frequently used assuming normal frequency distributions of capsule lengths, but many distributions are non-normal in acontiarian sea anemones. A traditional choice in these situations are non-parametric tests, although they are not as powerful as parametric tests. An extension of classical methods was developed by some authors; these models, called Generalized Linear Models (GLM), can be used under certain conditions with non-normal data. In view of the properties of our data, that are positive, skewed and with constant coefficient of variation, a GLM with gamma distribution and inverse link function was chosen to analyse the cnidae of acontia from the species Haliplanella lineata, Tricnidactis errans and Anthothoe chilensis. Graphical analysis of residuals showed that these assumptions were reasonable. This method allowed us to avoid transformation of data set and controversial cases in the limit of significance level. For this task, appropriate subroutines in GLIM language were written. In all cases highly significant differences were found between the specimens considered for every species and nematocyst type (b-rhabdoids, p-rhabdoids B1b and p-rhabdoids B2a).     

Characterization of nutrient status of Halamphora luciae (Bacillariophyceae) using matrix-assisted ultraviolet laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)

The effects of N and P depletion on the production and structural characterization of the cellular carbohydrate polymers of the estuarine diatom Halamphora luciae in batch culture were examined using matrix-assisted laser desorption-ionization time-of flight mass spectrometry (MALDI-TOF MS) complemented with monosaccharide composition determination and structural analyses by methylation of aqueous extracted product. The MALDI MS analysis of the cells showed a similar profile in control and N- and P-depleted media, with a displacement to higher molecular weight for cells grown in depleted media. In the monosaccharide analyses, both nutrient depletion and culture ageing led to an increase in glucose content, indicating that MALDI-TOF MS in whole cells was detecting the changes in chrysolaminarin. The maxima for the ions from f/2-P and to a lesser extent in f/2-N were displaced to higher m/z values indicating a higher degree of polymerization (DP). Methylation analysis confirmed the presence of chrysolaminarin, a (1→3)-β-d-glucan with branching in C2 and C6, where the glucan backbone had a substitution every four glucose residues. The (1→3)-β-d-glucan was also detected in the cingule by fluorescence with aniline blue.     

Patterns in the utilization of the intertidal salt marsh by larvae and juveniles of Fundulus heteroclitus (Linnaeus) and Fundulus luciae (Baird)

Larval and juvenile fishes were collected at low tide from the surface of an intertidal salt marsh on Sapelo Island, Georgia every 6 days from 25 May through 20 December 1982. Larval fishes were present in shallow puddles of tidal water on the marsh from the beginning of the sampling period until the end of October. Juveniles were present throughout the year. Fundulus heteroclitus (Linnaeus) and F. luciae (Baird) accounted for 96.3% (67.0% and 29.3%, respectively) of the 4355 fishes collected. These fishes exhibited synchronous, temporal pulses in larval abundance, suggesting that reproduction was discontinuous and controlled by the same factor(s) in both species. Larval F. heteroclitus inhabited aquatic micro-habitats near the upland edge of the intertidal marsh, but as the larvae grew to juvenile size (≈ 10 mm standard length) they moved to lower elevations near a tidal creek. Large juveniles and adults of F. heteroclitus infrequently occurred in the samples, presumably because they leave the intertidal marsh as the tide ebbs. F. luciae were rarely found in low marsh areas, but all age classes (including adults) occurred at higher elevations, supporting previous suggestions that this species prefers high marsh habitats. The vegetated, intertidal salt marsh appears to be the principal nursery habitat for both of these cyprinodontid species.     

A new species of Chiroptella Vercammen-Grandjean, 1960 (Acari: Trombiculidae) from diadem leaf-nosed bat Hipposideros diadema (Geoffroy) (Chiroptera: Hipposideridae) in Bali Island (Indonesia) with distribution records,hosts, and a key to the species of the genus

A new chigger mite Chiroptella baliensis n. sp. is described based on material from the diadem leaf-nosed bat Hipposideros diadema (Geoffroy) (Hipposideridae) in Bali Island (Lesser Sunda Islands, East Indonesia). With this newly described species, the genus Chiroptella includes 22 species, 13 in the subgenus Chiroptella Vercammen-Grandjean, 1960 (sensu stricto), and 9 in the subgenus Neosomia Vercammen-Grandjean, 1968. Species of Chiroptella are distributed throughout the Ethiopian region, the Oriental region, and the Australian region (and only marginally throughout the Palaearctic region) and are all associated with several families of bats. The paper also provides a key to all members of the genus and the new combinations for two species originally described as Chiroptella.

     

The macrofauna of a stony sand area in the German Bight (North Sea)

The sublittoral macrofauna of the Steingrund, a stony area east-northeast of Helgoland, was investigated from May till October 1991 using a van Veen grab and a small dredge. The diverse endo- and epifauna of the sandy bottoms, pebbles and boulders of this Saalian end moraine comprised 289 taxa, whereby the polychaetesMagelona papillicornis, Lanice conchilega andSpiophanes bombyx dominated in terms of abundance. Species rare in the German Bight, such as the spongeLeucandra fistulosa, the sea urchinEchinus esculentus, and the sea anemoneHaliplanella lineata, were also found. The two sample sets were processed separately with multivariate techniques, and differentiated on the basis of occurrence and numbers of the abundant species. The analysis of the grab samples revealed two types of theTellina-fabula-community. These associations were differentiated by the presence of species of the coarse-sand-inhabitingGoniadella-Spisula-community and were related to the distribution of the grain size of the sediment. Likewise, two epifaunal assemblages were distinguished. Sandy bottoms were characterized byOphiura albida, Liocarcinus holsatus andPagurus bernhardus, while boulders and pebbles were covered by a varied sessile and mobile epifauna dominated by the sessile bryozoanFlustra foliacea and the mobile pantopodeAechelia echinata. Numerical density, biomass and annual production estimates are in the range of values determined for the macrobenthos of the German Bight, while annual P/B ratios mounted up to 5.     

Phylogeographic analysis of the brown alga Cutleria multifida (Tilopteridales,Phaeophyceae) suggests a complicated introduction history

In depth genetic comparisons of populations of Cutleria multifida (Tilopteridales, Phaeophyceae) collected from Europe, the northwestern Pacific Ocean, Australia and New Zealand using the DNA sequences of four gene regions (the mitochondrial cox2 and cox3 genes, the intergeneric spacer region adjacent to cox3, and the open reading frame) suggested that the northwestern European and Japanese populations were considerably greater in terms of their genetic divergence than Mediterranean, Australian or New Zealand populations. The haplotypes of the populations in northwestern European (distribution range including the type locality, seven haplotypes) and Japanese populations (seven haplotypes) were unique except for one shared haplotype. There were weak but positive correlations between the geographical distance and the genetic divergence among northwestern European and Japanese populations. Moreover, both female and male gametophytes occurred in eight of the nine Japanese localities, suggesting Japanese populations showed normal sexual heteromorphic life history of the species. In light of these results, it appears that Japanese populations were native to the area despite earlier hypothesis. In contrast, Australian and New Zealand populations were composed of only one haplotype that is very close to those found in northwestern Europe and Japan, suggesting a recent introduction history from Europe (or from northeastern Asia via Europe) by ship transport to Australia and New Zealand. The Mediterranean populations included two haplotypes identical to those found in northwestern Europe and Japan, and it is suggestive of transoceanic introductions of some populations between Mediterranean and Japanese coasts.     

South American electric knifefishes of the genus Archolaemus (Ostariophysi,Gymnotiformes): undetected diversity in a clade of rheophiles

Neotropical electric knifefishes of the family Sternopygidae previously considered to represent a single relatively geographically widespread and morphologically variable species, Archolaemus blax, were analysed and found to represent a complex of five species, four of which are new to science. A fifth undescribed species from the Rio São Francisco basin outside the previous known range of the genus was identified. Recognized species of Archolaemus are: A. blax, previously thought to occur in the Rio Araguari, Rio Branco, Rio Tapajós, Rio Tocantins, and Rio Xingu, but which instead proved to be endemic to the Rio Tocantins; Archolaemus ferreirai sp. nov. from the Rio Mucajaí and Rio Uraricoera in the north‐eastern portions of the Amazon basin; Archolaemus janeae sp. nov. of the Rio Xingu and the upper Rio Tapajós, both southern tributaries of the mainstream Amazon; Archolaemus luciae sp. nov. of the Rio Trombetas, Rio Jari, and Rio Tapajós basins of the eastern Amazon, and the independent Rio Araguari draining into the Atlantic Ocean north of the mouth of the Amazon; Archolaemus orientalis sp. nov. of the São Francisco basin in eastern Brazil; and Archolaemus santosi sp. nov. of the Rio Jamari in the south‐western portion of the Amazon basin. The phylogenetic placements of Archolaemus and the recently described genus Japigny relative to the other members of the Eigenmanninae are discussed. A series of synapomorphies for Archolaemus are proposed and a hypothesis of the relationships within that genus is advanced. Rheophily of all members of Archolaemus is discussed, with the genus found to be the most specious clade within the Gymnotiformes living primarily in high‐energy settings. The reported anterior projection of the dentary teeth in A. blax was found to be a consequence of postmortem displacement.     

A comparison of Antarctic petrel (Thalassoica antarctica) diets with net samples of Antarctic krill (Euphausia superba) taken from the Prydz Bay region

Samples of the stomach contents of Antarctic petrels (Thalassoica antarctica) were obtained on board ship in the Prydz Bay region of Antarctica from birds which had spontaneously regurgitated. The weight of food and the species composition of the stomach contents were measured. Antarctic krill,Euphausia superba, the sole prey item taken, were compared to krill obtained by nets in the same region as part of a large-scale krill survey. Krill from petrel stomach samples were larger in mean size than those sampled by nets. This may be attributed to selection of the larger sized krill by the petrels, it may be caused by the nets sampling different populations of krill or it may be due to net avoidance by the larger krill.     

An ITS region phylogeny of Siderastrea (Cnidaria: Anthozoa): is S. glynni endangered or introduced?

The genus Siderastrea contains only five extant species, including Siderastrea glynni, which is one of the few recognized species of endangered stony coral. Cloned sequences of the internal transcribed spacer (ITS) region had low levels of intragenomic nucleotide diversity, and few alignment ambiguities, which allowed for the first species-level phylogenetic analysis of the genus. Results indicated an unexpected deep divergence between the Western-Pacific and Atlantic species. ITS region sequences indicated that S. glynni is not derived from S. savignyana, as previously thought. Instead, S. glynni shared identical sequence types with S. siderea in the Caribbean. Given a range of previously published evolutionary rates for the ITS region, it is unlikely that S. glynni represents the remnants of a population that was divided by the closure of the Central American Seaway (approximately 3–3.8 MYA). It is more likely that S. glynni originated by a breach of the Isthmus (approximately 2 MYA), or a contemporary introduction by ship.     

Coccinella septempunctata (Coleoptera,Coccinellidae): a species complex?

Marin, J., Crouau‐Roy, B., Hemptinne, J.‐L., Lecompte, E. & Magro, A. (2010). Coccinella septempunctata (Coleoptera, Coccinellidae): a species complex? —Zoologica Scripta, 39, 591–602. Coccinella septempunctata L., the seven spot ladybird is widely distributed across the Paleartic region. Based on a few morphological characteristics and geographical origin, some populations are recognized as distinct species, e.g., the North African Coccinella algerica Ková? and Japanese Coccinella brucki Mulsant later considered to be a subspecies –C. septempunctata brucki. The objective of this study is to discuss the taxonomic status of the seven spot ladybird, in particular whether it is a complex of species or the same species throughout the Paleartic region. The relationship between populations was clarified by using a combination of molecular and limited morphometric data and assessing potential reproductive barriers by means of cross breeding. Although there is considerable variation in the size of the spots on the elytra, the results of this study confirm that all studied populations belong to the same species.