Cytotaxonomy in distinct populations of Hoplias aff. malabaricus (Characiformes,Erythrinidae) from lower Paranapanema River basin

Cytogenetic and morphometric analyses were carried out in Hoplias aff. malabaricus specimens from six distinct populations from the lower Paranapanema River basin, located between the states of Paraná and São Paulo, Brazil. Measurements were also taken from a specimen collected in Surinam. In a population from a fish farm station at Universidade do Norte do Parana (EPUNOPAR), two sympatric cytotypes (2n = 40 and 2n = 42 chromosomes) are found. A population from a fish farm station at Universidade Estadual de Londrina (EPUEL) shows 2n = 42 meta–submetacentric chromosomes for males and females with a simple sex chromosome system of XX/XY type. Populations from the Vermelho and Rancho Alegre Rivers, Três Bocas Stream and Paranapanema River have 2n = 39 chromosomes in males and 2n = 40 chromosomes in females, showing a multiple sex chromosome system of X₁X₁X₂X₂/X₁X₂Y type. Twenty morphological variables were studied. These measurements were used for an analysis of the canonical variables and standard analysis of proportional measurements. The most variable measurements among the specimens are the maxilla length (MXL) and the pre‐dorsal distance (PDD). Analysis of canonical variables indicates three distinct groups in the first canonical axis formed by: (1) Três Bocas Stream, (2) Rancho Alegre + Vermelho River + EPUNOPAR and (3) EPUEL + Paranapanema River. This axis retained 79·4% of information from the original matrix. Analysis of morphometrics reveals differences among populations from the Paranapanema River basin and between these and the specimen from Surinam. The morphometric and cytogenetic differences among the studied populations suggest a species complex.     

New and previously described species of Urocleidoides (Monogenoidea: Dactylogyridae) infecting the gills and nasal cavities of Hoplias malabaricus (Characiformes: Erythrinidae) from Brazil

During an investigation of the biodiversity and structure of parasite communities among native populations of the erythrinid fish Hoplias malabaricus (Characiformes) from 7 rivers in Brazil, the following monogenoidean (Dactylogyridae) species were found: Urocleidoides malabaricusi n. sp., Urocleidoides naris n. sp., Urocleidoides cuiabai n. sp., Urocleidoides brasiliensis n. sp., and Urocleidoides eremitus Kritsky, Thatcher, and Boeger, 1986. Specimens considered as a new genus of Dactylogyridae were also found. The new species are mainly distinguished from the other 14 species of Urocleidoides in the general morphology of their copulatory and anchors/bar complexes. These new species and the new dactylogyrid genus are described, as well as supplemental observations and new illustrations of U. eremitus are provided. The present findings expand the known geographical distribution of species of Urocleidoides to southeastern and midwestern Brazil. A high speciation of this genus in the tropics is hypothesized, and it is briefly discussed.     

Genetic differentiation among distinct karyomorphs of the wolf fish Hoplias malabaricus species complex (Characiformes,Erythrinidae) and report of unusual hybridization with natural triploidy

In this study, genetic differentiation between karyomorphs A (2n = 42) and D (2n = 39/40) of the wolf fish Hoplias malabaricus, which is comprised of several cryptic species that present a wide variety of diploid chromosome numbers and sex chromosome systems, resulting in the identification of seven distinct karyomorphs (A–G), was investigated using a combination of molecular and cytogenetic tools. Deep sequence divergences for both karyomorphs were observed and indicate a long period of reproductive isolation between karyomorphs A and D. Additionally, one individual with 61 chromosomes was identified, which, as far as is known, is the first case of natural triploidy resulting from the hybridization between these highly differentiated karyomorphs of H. malabaricus. Molecular and cytogenetic analyses revealed that this allotriploid specimen carries two sets of maternal chromosomes from karyomorph D (2n = 40) and one set of chromosomes from karyomorph A (n = 21). Moreover, ribosomal sites and active nucleolus organizer regions from both parental contributors were found in the triploid hybrid. Considering the significant genetic distances between karyomorphs A and D, one of the primary reasons for the lack of recurrent reports of hybridization in the H. malabaricus species complex may be due to post‐zygotic barriers, such as hybrid sterility or unviability.     

Cardiac function of two ecologically distinct Neotropical freshwater fish: Curimbata, Prochilodus lineatus (Teleostei, Prochilodontidae), and trahira, Hoplias malabaricus (Teleostei, Erythrinidae)

An isometric muscle preparation was used to investigate the importance of the ventricular sarcoplasmic reticulum (SR) and extracellular Ca(2+) (2.5 up to 10.5 mM) to force generation at 25 degrees C (acclimation temperature) in two ecologically distinct Neotropical teleost fish: Curimbata (active species), and trahira (sedentary species). The post-rest force was studied with and without 10 muM ryanodine in the medium. The positive inotropism observed for both species in response to increases on extracellular Ca(2+) reflected a greater Ca(2+) influx through sarcolemma, as well as an increase in Ca(2+) liberation from the SR by the Ca(2+)-induced Ca(2+) release mechanism. The significant post-rest potentiation recorded for the curimbata and trahira control preparations (3.22+/-0.24 to 6.55+/-0.77 mN mm(-2) and 0.74+/-0.07 to 2.26+/-0.26 mN mm(-2), respectively), was completely inhibited by the addition of ryanodine to the bathing medium, suggesting a potential functionality of SR for both species. Considering the differences in these species habitats, modes of life and levels of activity and the fact of a probable SR Ca(2+) cycling in a physiological temperature, we suggest that the functionality of the SR in these species is probably related to their phylogeny.     

Comparative cytogenetics of giant trahiras Hoplias aimara and H. intermedius (Characiformes, Erythrinidae): chromosomal characteristics of minor and major ribosomal DNA and cross-species repetitive centromeric sequences mapping differ among morphologically identical karyotypes

Karyotype and cytogenetic characteristics of 2 species of giant trahiras, Hopliasintermedius, S?o Francisco river basin, and Hopliasaimara, Arinos river (Amazon basin), were examined by conventional (C-banding, Ag-NOR, DAPI/CMA(3) double-staining) and fluorescent in situ hybridization (FISH) with 5S, 18S rDNA probes and cross-species Cot-1 DNA probing. Both species invariably had diploid chromosome number 2n = 50 and identical karyotypes composed of 10 pairs of metacentric and 15 pairs of submetacentric chromosomes. On the other hand, staining with base-specific fluorochromes (CMA(3), DAPI) and FISH mapping of repetitive DNA sequences showed extensive interspecific differences: while the genome of H. aimara had one submetacentric pair bearing CMA(3)-positive (DAPI-negative) sites, that of H. intermedius had 4 such pairs; while FISH with a 5S rDNA probe showed one (likely homologous) signal-bearing pair, that with 18S rDNA displayed one signal-bearing pair in H. intermedius and 2 such pairs in H. aimara. Cross-species FISH probing with Cot-1 DNA prepared from total DNA of both species showed no signals of Cot-1 DNA from H. aimara on chromosomes of H. intermedius but reciprocally (Cot-1 DNA from H. intermedius on chromosomes of H. aimara) displayed signals on at least 4 chromosome pairs. Present findings indicate (i) different composition of repetitive sequences around centromeres, (ii) different NOR phenotypes and (iii) distinct taxonomic status of both giant trahira species.     

Polysiphonia freshwateri sp. nov. and Polysiphonia koreana sp. nov.: two new species of Polysiphonia (Rhodomelaceae,Rhodophyta) from Korea

Polysiphonia sensu lato comprises approximately 200 species, which are currently assigned to several different genera. To date, one of these genera, namely, Polysiphonia, has been reported to have 17 species. Here, we describe for the first time P. freshwateri sp. nov. and P. koreana sp. nov. from Uljin and Ulleung Island, Korea, based on morphological and molecular evidence. Polysiphonia freshwateri sp. nov. and P. koreana sp. nov. are characterized by having the typical Polysiphonia features. Polysiphonia freshwateri sp. nov. is further characterized by having abundant trichoblasts, conspicuous scar cells, and tetrasporangia arranged in spiral series. Polysiphonia koreana sp. nov. is further characterized by having very scarce scar cells placed between two pericentral cells, from which cicatrigenous branches arise. The results of our rbcL sequence analyses support the taxonomic placement of P. freshwateri sp. nov. and P. koreana sp. nov. within Polysiphonia.     

The response of two Bactrocera species (Diptera: Tephritidae) to fruit volatiles

Bactrocera dorsalis and B. correcta are serious pests of agricultural fruit crops. Both species are widely distributed in tropical and subtropical countries, especially in Asia. For integrated management of both Bactrocera species, understanding their olfactory behavior is vital for designing reliable control strategies. In this study, the response of female B. dorsalis and B. correcta adults to three main volatile components of fruits was evaluated using the Y-tube olfactometer. Our results showed that at higher concentrations all volatile components, except α-humulene and its combination with β-caryophyllene, attracted significantly more B. dorsalis than the untreated arm. For B. correcta, all the volatile components attracted significantly more females in the treated arm than the untreated arm. However, at 5% and 1% concentration, all the volatile components had similar attraction for B. dorsalis females. In the case of female B. correcta, the percentage of attraction was similar for all the individual volatile chemicals and their respective mixtures at 10% concentration. While, at 5% and 1% concentrations, the percentage of attraction was significantly higher for a mixture of β-caryophyllene and α-humulene than that of individual volatile components and all possible mixture of two and three volatile components. Based on the olfactometer results, this study concluded that 3-carene and the mixture of β-caryophyllene and α-humulene are strong attractants for female flies of B. dorsalis and B. correcta, respectively. This study might be helpful for the bait application against the female adults of B. dorsalis and B. correcta in farms and orchards.     

Comparative susceptibility of two different genetic types of tilapia to Neobenedenia sp. (Monogenea)

Two different genetic types of tilapia, Mozambique tilapia Oreochromis mossambicus (MT), and Pargo-UNAM (PU; a synthetic hybrid whose genetic composition is 50% Florida red tilapia, 25% Rocky Mountain tilapia, and 25% red variant Oreochromis niloticus), were acclimatized to salinity and exposed to seawater from the Gulf of Mexico off the port of Veracruz, Mexico. Both fish types were infected by the monogenean ectoparasite Neobenedenia sp. and were killed within 2 to 3 wk. A crude worm extract was prepared from whole specimens collected during the original outbreak and used to immunize naive hosts of the same 2 types of tilapia. Immunized fish were then exposed to seawater, which resulted in Neobenedenia sp. infection. Immunization did not confer any protection against Neobenedenia sp. infection. However, the experiment enabled detailed analysis of the dynamics of infection and comparison of the effects of the parasite on the 2 host types. Although both tilapia types exhibited similar resistance to infection (as they harbored similar parasite burdens in the early phase of infection), PU is less tolerant to Neobenedenia sp., as a mean parasite abundance of ca. 50 worms fish-' killed all hosts within a fortnight, while 22% of MT survived up to 3 wk, harboring a mean parasite abundance of ca. 900 worms fish-'. Our results suggest that, as reported elsewhere, Neobenedenia sp. could negatively affect mariculture off the Mexican coast of the Gulf of Mexico.     

Chromosomes of two species of Tisbe (Copepoda, Harpacticoida) belonging to different groups of sibling species

Karyological investigations curried out on Tisbe marmorata and T. dobzhanskii confirmed the diploid value 2 n = 24 for the former species; on the basis of more than 200 observations it was ascertained that the diploid number of the latter species corresponds to 22, in contrast with a previous report. The karyotypes of these two species differ both in morphology and in location of satellites, not only from each other, but also from all other species so far examined. A close comparison of the two species with their respective siblings is made.     

Descriptions of Protospathidium serpens (Kahl, 1930) and P. fraterculum n. sp. (Ciliophora, Haptoria), two species based on different resting cyst morphology

Protospathidium serpens (Kahl, 1930) is frequent in semiterrestrial and terrestrial habitats worldwide. Conventionally, all populations are considered as conspecific because they have very similar overall morphologies and morphometrics. We studied in detail not only the morphology of the vegetative cells but also the resting cysts using live observation, protargol impregnation, and scanning electron microscopy. These revealed a cryptic diversity and biogeographic pattern in details of the dorsal brush and cyst wall morphology. The cyst wall is spiny in the Austrian specimens, while smooth in the South African and Antarctic populations. Accordingly, P. serpens consists of at least two species: P. serpens (with spiny cyst wall) and P. fraterculum n. sp. (with smooth cyst wall); the latter is probably composed of two distinct taxa differing by the absence (South African)/presence (Antarctic) of a monokinetidal bristle tail in brush row 3, the number of dikinetids comprising brush row 1 (seven versus three), and the total number of brush dikinetids (29 versus 17). Protospathidium serpens is neotypified with the new population from Austria. The significance of resting cyst morphology is discussed with respect to alpha-taxonomy and overall ciliate diversity.     

A new combination in Aulonemia (Poaceae: Bambusoideae: Bambuseae) based on floral analysis, anatomical features, and distribution

Recent bamboo collections from Brazil, and the study of specimens from several Brazilian herbaria revealed that the species described as Eremocaulon setosum, subtribe Guaduineae, in fact fits within the Arthrostylidiinae genus Aulonemia, based on floral and anatomical characters. Several characters found in this species, such as paniculate determinate synflorescences, solitary spikelets, an abaxial marginal green stripe on the foliage leaf blades, absence of stomata on the entire adaxial side of the leaf blade, and intercostal fibers in the mesophyll are typical features of the subtribe Arthrostylidiinae. The new combination Aulonemia setosa is here proposed, an epitype is designated, and a broader distributional range of this species is documented.     

Characterization of invasive fish species in a river transposition region: evolutionary chromosome studies in the genus <Emphasis Type="Italic">Hoplias</Emphasis> (Characiformes,Erythrinidae)

Karyotypic analyses were performed in fishes from the genus Hoplias (H. malabaricus and H. lacerdae groups) from the São Francisco River basin (Brazil), in an impacted region by a river transposition which altered the local ecology and fish fauna. The karyotypes were investigated using chromosomal markers obtained from classic and molecular cytogenetics (Giemsa, CMA₃ and DAPI staining, C-banding, Ag-NORs, and FISH with 18S rDNA, 5S rDNA and 5SHindIII satellite DNA probes). Two karyotypic forms were found for the H. malabaricus group—karyomorph F, corresponding to the native form from the São Francisco River basin, and karyomorph A, corresponding to the invading form from the Upper Paraná River basin. Specimens from the H. lacerdae group exhibited striking chromosome differences in relation to the H. malabaricus group, thereby enabling good cytotaxonomic characterization and inferences regarding the karyotype evolution of these groups.     

Inermicapsifer beveridgei n. sp. (Cestoidea: Anoplocephalidae) from Procavia capensis (Hyracoidea) in Israel, with notes on two species of Hymenolepis

Inermicapsifer beveridgei n. sp. from Procavia capensis differs from all other species in the genus in having 150-174 testes per segment. The closest species is I. hyracis (Rudolphi, 1810) Janicki, 1919, with 75-120 testes. Hymenolepis vogeae Singh, 1956 and H. horrida (Linstow, 1901) Lühe, 1910, are briefly discussed.     

Biological studies on two neotropical egg parasitoid species: Trichogramma nerudai and Trichogramma sp. (Hymenoptera: Trichogrammatidae)

The main biological attributes of two Neotropical egg parasitoids, the arrhenotokous Trichogramma nerudai and the thelytokous Trichogramma sp., were assessed under controlled laboratory conditions. Developmental time from egg to adult, and parasitoid survival, fecundity and fertility were studied using life tables. Results showed that T. nerudai had a faster developmental time than Trichogramma sp. (13.014±0.4019 and 13.595±0.4931 days, respectively). Both species showed similar life table statistics, r_m was 0.222 and 0.225 for T. nerudai and Trichogramma sp., respectively. Parasitoid survival averaged 95% for both species. The results obtained are discussed in the context of selecting one of these natural enemies as a potential biological control agent for the European pine shoot moth Rhyacionia buoliana (Lepidoptera: Tortricidae) in pine forests and the codling moth Cydia pomonella (Lepidoptera: Tortricidae) in apple orchards in Argentina.     

Helminths of rodents and marsupials from Papua New Guinea,with the description of two new species,Echinostoma echymiperae n. sp. (Digenea: Echinostomatidae) and Vampirolepis peroryctis n. sp. (Cestoda: Hymenolepididae)

The following rodents and marsupials from the Western Highlands of Papua New Guinea have been examined for helminths: Anisomys imitator, Melomys spp., Pogonomelomys ruemmleri, Rattus spp., Echymipera kalubu and Peroryctes raffrayanus. Two new species and a number of new host records are reported. Echinostoma echymiperae n. sp., a digenean from the intestine of Echymipera kalubu, is characterised by the number of collar spines, the body armature and the shape and position of the gonads. Vampirolepis peroryctis n. sp., a cestode from the intestine of Peroryctes raffrayanus, is characterised by the length of the rostellar hooks, the shape of the ovary, the arrangement of the testes in a triangle and the extent of the cirrus-sac. Hymenolepis aklei, H. bradleyi, H. antechini, H. bettongiae, H. cercarteti, H. isoodontis and H. potoroi are transferred to Vampirolepis as new combinations. E. kalubu is a new host for Linstowia semoni and Pogonomelomys ruemmleri is a new host for Hymenolepis diminuta. V. peroryctis is the first platyhelminth to be reported from Peroryctes raffrayanus and Raillietina (Raillietina) sp. the second to be reported from the genus Melomys.