Co-generic Species Research Articles

Local adaptation in rotifer populations

The adaptation of organisms to their environment has been a subject of study for a long time. One method to study adaptations in populations involves comparing contemporary populations of the same species under different selective regimes, in what is known as a ‘local adaptation’ study. A previous study of the cyclically parthenogenetic rotifer Brachionus plicatilis found high heritabilities for some life-history traits. Some of these life-history traits significantly differed among six populations from Eastern Spain and data suggested some traits to have higher evolutionary rates than neutral genetic markers. Here, by studying the same B. plicatilis populations, we examine the variation and possible local adaptation of their main life-history traits, closely related to fitness, in relation to habitat salinity and temperature. These environmental factors have been shown to play a key role in the ecological differentiation among co-generic species of B. plicatilis. The results obtained in this study show that: (1) the seasonality of rotifer populations from Eastern Spain has profoundly influenced sexual reproduction strategies; (2) salinity is probably a key factor in the ecological specialization of some populations; and (3) rotifer populations harbour high variability in their fitness components.

Nouvelles données sur le genre Imerites Rouchadzé, 1933 (Ammonitida, Ancyloceratina) ; réponses et précisions apportées au travail de Bert, Delanoy et Canut, 2009

This work is mainly an answer to the work of Bert, Delanoy and Canut, on the genus Imerites Rouchadzé, and we add also some points to the knowledge of this genus. An answer is given for the implication of one of the authors (J.V.) of this present work, about the origin of the genus Imerites Rouchadzé, and some significant bibliographic references, not named in the 2009 work, are specified and placed in their context. The characteristics of the ornamental stage “Pseudoshasticrioceras” mainly defined by an oval and compressed section of the whorls and by regular ventrolateral clavi, well marked, which frame the venter in a typical way (Bert et al., p. 181), don’t allow to affirm the presence of this stage during the ontogeny of all species of the genus Imerites Rouchadzé, contrary to what Bert, Delanoy and Canut (p. 30, 31) wrote. The type-species of the genus Imerites Rouchadzé is made clear by the application of the rules of the I.C.Z.N. code. The article 23, with the paragraph 23.1 of the I.C.Z.N. code, imply the senior synonymy of Imerites cristatus (Orbigny) on Imerites giraudi (Kilian), even if the Kilian's species is still the type species of the genus Imerites Rouchadzé. The taxinomical validity of the species Imerites cristatus (Orbigny) is confirmed. Its morphological variability is clarified by the distinction of four referential morphotypes, Cristatus, Giraudi, Favrei and Raricostatum. Consequently, the assumption of a shape-dimensional dimorphism into the populations of the genus Imerites Rouchadzé is rejected, awaiting irrefutable proof. A new species, Imerites stephaniae sp. nov., is described. It was collected in the Gerhardtia sartousiana Zone, in the uppermost part of the Gerhardtia provincialis Subzone, and it is a probable ancestor of the cogeneric species of the Imerites giraudi Zone.

Adaptive Evolution in the GAF Domain of Phytochromes in Gymnosperms

The GAF domain of phytochrome is essential for photoconversion and signal transduction. In gymnosperms, it exists in all members of the phytochrome family that experience gene duplication. Maximum-likelihood models of codon substitution can provide a framework for constructing likelihood ratio tests of changes in selective pressure and make clear predictions about patterns of genetic change following gene duplication. In this study, 68 gymnosperm GAF sequences were analyzed to identify lineages and sites under positive selection. Our results indicate that (1) positive selection at a few sites (3.6%), rather than relaxation of selective constraints, has played a major role in the evolution of the gymnosperm GAF domain; (2) strong positive selective pressure tends to occur in the recent PHYP lineages of cogeneric species, but is absent in old lineages consisting of distantly related species; and (3) the selective pressure indicated by the omega ratio varies greatly among lineages and sites in the GAF domain.

Contrasting sensitivities to toxicants of the freshwater amphipods Gammarus pulex and G. fossarum

Amphipods are an important component of freshwater ecosystems. They are very often used in ecotoxicology, particularly the freshwater amphipod Gammarus pulex. However, there is scarce information on the sensitivity to toxicants of other species within the genus Gammarus. The present study aims to: (1) to compare sensitivities to ivermectin and cadmium between two species of freshwater amphipods (G. pulex and G. fossarum); (2) to compare sensitivities to these toxicants between juveniles and adults within each species; and (3) to assess whether the sensitivity to toxicants of these co-generic species is related with the wideness of their natural distribution area. Eight independent short-term bioassays (96 h) were conducted to assess sensitivity for ivermectin and cadmium for juvenile and adult life stages for each species. The LC50 (mortality) and EC50 (mortality plus immobility) were calculated to 48 and 96 h of continuous exposure. Our results showed that G. pulex was less tolerant to ivermectin than G. fossarum, the reverse being true for cadmium. In general, juveniles of both species were less tolerant to cadmium than adults. In the case of ivermectin, only for G. fossarum EC50 values were different between life stages. These results suggest that the risk assessment of toxicants to freshwater amphipods should include bioassays with the most sensitive species and life stage.

Tyrrhenian basins of Ligury as a new peri-Mediterranean ichthyogeographic district? Population structure of Telestes muticellus (Osteichthyes, Cyprinidae), a primary freshwater fish

The phylogeographic structure of vairone (Telestes muticellus), a primary freshwater fish endangered in a large part of its distributional range, was assessed: (i) to reconstruct the complex dispersion pattern in the upper Tyrrhenian hydrographic basins of Ligury, actually not recognised as peri-Mediterranean ichthyogeographic district, and (ii) to evidence the shape of population genetic structure as useful tool for future conservation strategies. A partial fragment of mitochondrial DNA cytochrome b (497 bp) was sequenced in 109 specimens sampled from eight populations, along an east–west geographic gradient. Fourteen haplotypes were identified, confirming the evolutionary distance between the two co-generic species: T. muticellus as ‘Ligurian’ clade and T. souffia as ‘French’ clade. The Nested Clade Analysis (NCA), the population genetic variability and population structure suggested a natural colonization occurred throughout the crossing of Alpine and Apennine watershed. The hierarchical Analysis of Molecular Variance (AMOVA) confirmed a geographic distinction between the populations from western (WTL) and from eastern (ETL) Tyrrhenian basins of Ligury colonised through the river capture processes along the Maritime Alpine watershed (Padano-Venetian district) and along the Apennine watershed (Tuscano-Latium district), respectively. Our results, evidencing the lack of genetic contiguity among vairone populations of the upper Tyrrhenian hydrographic basins of Ligury, allowed to recognise the presence of two management units (MUs) for its conservation.

Contribution to the knowledge of the genus Loxosomella (Entoprocta) from the Spanish Mediterranean Sea, with the description of a new species, Loxosomella ameliae sp. nov.

A study of loxosomatidae inhabiting demosponges of the genera Ircinia and Sarcotragus in the Iberian Mediterranean Sea has shown the occurrence of two species. One of them, identified as Loxosomella pes, is recorded for the first time from Spanish waters and some biometric data of the studied population are provided. The other species is new and is here described as Loxosomella ameliae sp. nov. The existence of a wide field of conspicuous gland cells and some features of the foot and calyx characterize the new species and distinguish it from other cogeneric species. With this new species, a total of five species of Loxosomella reported from sponges are known from the Mediterranean Sea.

Individual growth of Heleobia piscium in natural populations (Gastropoda: Cochliopidae) from the multiple use natural Reserve Isla Martin Garcia, Buenos Aires, Argentina

The present work analyses the individual growth of Heleobia piscium in natural conditions in coastal drainage channels of the Multiple Use Natural Reserve Isla Martín García, Buenos Aires, Argentina. Isla Martín García is located in the Upper Río de la Plata, to the south of the mouth of the Uruguay river (34 degrees 11' 25" S and 58 degrees 15' 38" W). Monthly collections were made from July 2005 to July 2006 in the eastern part of the island (Arena Beach). The population of H. piscium showed a complex and dynamic structure of sizes during a long period of the annual cycle. Two cohorts could be detected. The Bertalanffy growth equation was: Lt = 6 (1-e -1.85 (t+0.38)) and Lt = 3.9 (1-e -0.19 (t+4.84)) for cohorts 1 and 2, respectively. The pattern of population growth displayed a staggered model, where the greatest growth is observed during the summer. The reproductive period occurred during six months, from the beginning of summer to middle of fall. Based on only one reproductive effort, this pattern is not similar to that of other cogeneric species already studied.

Cytotaxonomic diagnosis of Trichomycterus diabolus (Teleostei: Trichomycteridae) with comments about its evolutionary relationships with co-generic species

The karyotype and the Ag-NOR location of a sample of Trichomycterus diabolus collected in the córrego Hortelã (Botucatu, São Paulo, Brazil) are described. The species exhibited 2n=56 chromosomes (42 metacentrics, 12 submetacentrics and 2 subtelocentrics) and the nucleolus organizing region located near to the centromere on the long arm of the largest metacentric pair. The presence of 2n=56 chromosomes in T. diabolus is an interesting characteristic since until now all cis-Andean species karyotyped presented 2n=54 chromosomes while almost all trans-Andean species presented different diploid numbers. The possible origin of this unexpected karyotypic form is discussed.

Comparative proteomics and subtyping of venom phospholipases A 2 and disintegrins of Protobothrops pit vipers

To explore the venom diversity and systematics of pit vipers under the genus Protobothrops, the venom phospholipases A 2 (PLA 2s) of P. mangshanensis, P. elegans and P. tokarensis were purified and characterized for the first time. The results were compared with the corresponding venom data of other co-generic species including P. mucrosquamatus, P. flavoviridis and P. jerdonii. Based on sequence features at the N-terminal regions, we identified five PLA 2 subtypes, i.e., the Asp49-PLA 2s with N6, E6 or R6 substitution and the Lys49-PLA 2. However, not all subtypes were expressed in each of the species. Venom N6-PLA 2s from P. mangshanensis and P. tokarensis venom were weakly neurotoxic toward chick biventer cervicis tissue preparations. The venoms of P. tokarensis and P. flavoviridis contained identical PLA 2 isoforms. In most Protobothrop disintegrins, sequences flanking the RGD-motif are conserved. Phylogenetic analyses based on amino acid sequences of both families of the acidic PLA 2s and the disintegrins clarify that these species could belong to a monophyletic group.

Two unknown species of Mollusca Gastropoda from the Archipelago Fernando de Noronha (Brazil), with description of a new species belonging to the genus <i>Phidiana Gray</i>, 1850 and a new record of <i>Dendrodoris senegalensis</i> Bouchet, 1975

The Brazilian Archipelago of Fernando de Noronha lies off Cape Sao Roque, State of Rio Grande do Norte, about 195 nautical miles offshore. Only a few faunistic lists of this tropical archipelago have been published, and only four species of Gastropoda Opisthobranchia were cited. In this paper two species of Opisthobranchia Nudibranchia are recorded from this Archipelago. Dendrodoris senegalensis Bouchet 1975, known from Cape Verde and Senegal, amplifies its extension range toward the Western Atlantic. The brazilian specimens differ from the African specimens, in the presence of a completely white branchial tuft. Phidiana riosi sp nov clearly differs from other co-generic species in its colour pattern, having a red ground colour, with numerous white spots scattered on the dorsum. The rhinophores are orange and the cerata white with the cnidosac orange. Internally, this species has jaws with a single row of denticles, and the radular teeth have a central cusp with 7-8 denticles each side. The penis is armed with a black spine and the seminal receptacle connects with two independent ducts, the oviduct and the vaginal duct. Both species are compared with other similar taxa.

A Quantitative Morphological Analysis of Some Hypericum Species

Hypericum perforatum L. (Hypericaceae) is a medicinal plant of considerable interest for the therapeutic potentialities of its biologically active compounds. Due to the presence of hybrids and frequent adulterants from other species of Hypericum, the identification of the drug obtained of this species is difficult. Therefore, a quantitative morphological analysis of the leaf epidermises of H. hircinum L. and H. perfoliatum L. compared with H. perforatum L., carried out by means of scanning electron microscopy and image analysis, was performed to identify phytognostic markers useful for the characterization of these different Hypericum species. Size and shape parameters of the leaf surface cells have permitted a comparative study of the cogeneric species examined, providing a key factor in their recognition and/or selection. Unlike the methods employed so far, the results obtained by means of this innovative kind of analysis supply a valid criterion, not only for the morphological differentiation of the Italian Hypericum species studied, but also for an accurate and reproducible quality control of the commercial samples, often made up of drugs obtained from different species, subspecies and varieties.

Morphological and hormonal parameters in two species of macaques: impact of seasonal breeding.

To compare physiological and developmental differences between two cogeneric species that differ by seasonal vs. aseasonal breeding, values for morphological measurements, testicular volume, serum testosterone, estradiol, and dehydroepiandrosterone-sulfate levels were obtained from 53 rhesus during the early breeding season, as well as 41 pig-tailed macaque males maintained at the Tulane Primate Center. The two species exhibited similar body size, testosterone, and estradiol levels, but differed substantially in testicular volume (3.00 +/- 1.7 vs. 1.72 +/- 1.3 cc), abdominal skinfold measures (15.7 +/- 9.2 vs. 9.0 +/- 7.7 mm), and DHEA-S levels (18.0 +/- 11.7 vs. 7.6 +/- 5.4 microg/dl). Significant interaction effects for species by age group were found for weight, tricep circumference, length, and estradiol level. In addition, length was more closely related to testicular volume among rhesus compared to pig-tailed macaques, suggesting different developmental patterns between the species. Predictors of hormonal levels differed between the two species. In the rhesus, estradiol levels were related to testicular volume and testosterone levels while there were no anthropometric predictors of testosterone or DHEA-S. For the pig-tailed macaques, testicular volume was related to tricep circumference, testosterone to triceps skinfold and testicular volume, and estradiol to weight. It is argued that rhesus have larger testes for body size and more abdominal fat deposits during the early breeding season relative to pig-tailed macaques reflecting the increased demands of sperm competition in a seasonally breeding species. Hormonal differences associated with the difference in breeding system appear to be primarily related to adrenal rather than testicular activity.

A New Species of the Genus Propedies Hebard (Acridoidea: Acrididae: Melanoplinae) from Northern Argentina

A New Species of the Genus Propedies Hebard (Acridoidea: Acrididae: Melanoplinae) from Northern Argentina

Description of a new genus: Hammeriella gen. n. - from South America and a new family - Hammeriellidae fam. n. (Acari, Oribatei)

Hammeriella gen. n. and, Hammeriellidae fam. n. (Acari, Oribatei) from South America are described. Hammeriella is also recorded from "Tierra del Fuego" (Chile) and from Argentina. The type species of Hammeriella, Pedrocortesia grandis Hammer, is fully redescribed and the cogeneric species, Pedrocortesia australis Hammer, is diagnosed in comparison with the type species, both being transferred to Hammeriella. The redescriptions were made from syntypes deposited in the Zoologisk Museum of Copenhagen, sent on loan for this study.

Pharmacognostic Studies onDatura metelLinnaeus the Anatomy of the Leaf

AbstractHistologically Datura metel L. is readily distinguished from other cogeneric drug species by its smooth cuticle, basal width of covering trichome (measuring up to 34 μ), presence of stomata on both upper and lower leaf epidermides, non-warty stalk of glandular trichomes, collapsed stomata on leaf epidermis. Figures of quantitative microscopy are reported. Histological characters used to complement morphological ones enable one to identify drug in entire or powdered form.

Feeding behaviour of the felt-, sponge-, and coral-feeder sea stars, mainlyCulcita schmideliana

1. On the coral reefs of the Tuléar region (S. W. Madagascar), the feeding behaviour of sea stars, in particular the speciesCulcita schmideliana has been studied. It feeds in its usual biotope, the sea-grass beds of the inner reef flats, on the epibenthic film of the substrates, of the leaves, but also commonly on sponges, mainly the symbioticGellius cymiformis (associated withCeratodictyon spongiosum); 2. In the moat (residual pools, coral-built formations) of the inner reef flat where the population was poor in 1965 but equal to that of the sea-grass bed in 1972, the cushion sea star feeds on the epibenthic felt, but also on the living corals (Galaxea, Goniopora) and on soft corals(Xenia). This latter diet is very close to that of the Pacific cogeneric species,Culcita novaeguinae. 3.Acanthaster planci populations are normal on the reef flats of the region (but a little more dense on the fringing reef under silty deposits). Only a beginning of an infestation was observed in May 1972, but it disappeared later (condition 6 of Chesher's classification). 4. Others Oreasterids feed mainly on epibenthic film, extruding their stomachs on the substrates.Protoreaster nodosus has a larger distribution thanP. lincki, Pentaceraster mammillatus andChoriaster granulosus. 5. Among others sea stars,Asterina burtoni seems to be a large predator of species living under dead coral blocks (sponges, ascidiacea) of the boulder tracts and of the rubbly flats.

Seed size and mass in relation to environment

Propagule masses are here recorded for shade-tolerant species belonging to 20 genera which show an average of about three-and-one-third times the mass of the propagules of co-generic species of open habitats. These are additional to the 30 genera already reported on by the author. Propagules of cornfield weeds belonging to 18 genera are shown to exhibit greater masses than their congeners, even though some of these are shade-tolerant, and this, it is suggested, may be the outcome of the prolonged selective effect of ‘winnowing’. Other causes of heavy propagules of open-habitat species are suggested, indicative of natural selection.

Population Dynamics and Nesting Behaviour of Eumenes colona (Hymenoptera) in Jamaica

The biology of the potter wasp Eumenes colona Saussure is similar to many other cogeneric species. Nest sites are selected to protect cells from rain and to receive sun. Porous limestones and annual rainfall > 1905 mm limit nest distribution in Jamaica. Minimum fecundity was 7.14 ? 2.79 eggs per nesting female. Developmental mortality averaged 40.5 %. Melittobia chalybii Ashmead (Eulophidae) and Amobia floridensis (Townsend) (Calliphoridae), acting density-dependently, caused 55.40% and 14.5 % mortality, respectively. Pre-productive females showed at least 22.5 % mortality in areas of low density. Pachodynerus nasidens Latr. and Monobia mochii Soika (Eumenidae) are inquilines in old cells and since both are host to M. chalybii, probably increase its predation on E. colona. Sceliphron assimile Dahlbom (Sphecidae) is more abundant than E. colona, but does not compete for nesting sites. A similar development mortality (40.1 %) to Eumenes, is not responsible for its greater abundance.