Isolation and characterization of microsatellite loci in Pimelodus maculatus (Siluriformes: Pimelodidae)

To evaluate genetic variability in Pimelodus maculatus, a small migratory catfish common in South America, we isolated and characterized several microsatellite markers from individuals collected from a population in the River Grande (Brazil). A total of 11 loci were obtained and analyzed. All the loci were polymorphic, with the number of alleles ranging from three to 27 per locus. Observed and expected heterozygosities ranged from 0.5 to 0.89 and from 0.53 to 0.95, respectively. These polymorphic markers can be used as effective tools to study the genetic structure in populations of this species.     

Effect of some metal ions on blood and liver delta-aminolevulinate dehydratase of Pimelodus maculatus (Pisces, Pimelodidae)

1. delta-ALA-D from Pimelodus maculatus was inhibited in vitro by Cd2+ greater than Pb2+ greater than Hg2+ greater than Cu2+ greater than Zn2+ in blood and by Pb2+ greater than Cd2+ greater than Hg2+ greater than Cu2+ = Zn2+ in the liver. 2. Kinetic analysis of the inhibition by the metal ions showed that Cd2+ and Hg2+ act as non-competitive inhibitors on both sources. 3. Pb2+ showed a mixed type of inhibition in blood and a non-competitive type in the liver. 4. Zn2+ acted as a competitive or mixed inhibitor, on both sources, depending on concentration.     

Ecomorphological patterns of aerial feeding in oscines (Passeriformes: Passeri)

The hindlimb (myology and osteology) of swallows (Hirundinidae) is studied and compared with that of seven other passerine families to identify ecomorphological patterns. Muscular and osteological differences are found among swallow species and associations between morphology and foraging technique are examined. We explain morphological differences found in hirundinids as adaptations favouring flexion and adduction of the legs in these aerial foragers, which devote very little time to cursorial locomotion. This adaptive hypothesis is tested using a phylogenetic approach on the basis of an available molecular phylogenetic hypothesis. A clear ecomorphological pattern emerges relating foraging behaviour and pelvic morphology in hirundinids: aerial feeding technique is correlated with short distal leg segments, a large pelvis, a medial insertion of M. iliotibialis cranialis, an absence of pars accessoria of M. flexor cruris lateralis and a fused M. pubo-ischiofemoralis.     

Molecular Phylogeny and Biogeographic History of the Armored Neotropical Catfish Subfamilies Hypoptopomatinae,Neoplecostominae and Otothyrinae (Siluriformes: Loricariidae)

The main objectives of this study are estimate a species-dense, time-calibrated molecular phylogeny of Hypoptopomatinae, Neoplecostominae, and Otothyrinae, which together comprise a group of armoured catfishes that is widely distributed across South America, to place the origin of major clades in time and space, and to demonstrate the role of river capture on patterns of diversification in these taxa. We used maximum likelihood and Bayesian methods to estimate a time-calibrated phylogeny of 115 loricariid species, using three mitochondrial and one nuclear genes to generate a matrix of 4,500 base pairs, and used parametric biogeographic analyses to estimate ancestral geographic ranges and to infer the effects of river capture events on the geographic distributions of these taxa. Our analysis recovered Hypoptopomatinae, Neoplecostominae, and Otothyrinae as monophyletic with strong statistical support, and Neoplecostominae as more closely related to Otothyrinae than to Hypoptopomatinae. Our time-calibrated phylogeny and ancestral-area estimations indicate an origin of Hypoptopomatinae, Neoplecostominae, and Otothyrinae during the Lower Eocene in the Atlantic Coastal Drainages, from which it is possible to infer several dispersal events to adjacent river basins during the Neogene. In conclusion we infer a strong influence of river capture in: (1) the accumulation of modern clade species-richness values; (2) the formation of the modern basin-wide species assemblages, and (3) the presence of many low-diversity, early-branching lineages restricted to the Atlantic Coastal Drainages. We further infer the importance of headwater stream capture and marine transgressions in shaping patterns in the distributions of Hypoptopomatinae, Neoplecostominae and Otothyrinae throughout South America.     

Analyses of Nucleolus Organizer Regions and Heterochromatin of Pimelodus Maculatus (Pisces, Pimelodidae)

Eighteen specimens of Pimelodus maculatus collected from Tibagi River (Sertaneja, PR, Brazil) were analyzed cytogenetically. The diploid number of 56 chromosomes was observed and karyotype was 20 M + 20 SM + 10 ST + 6 A with fundamental number (FN) of 106. Results of analyses from the nucleolus organizer regions (NORs), obtained by AgNO₃, CMA₃ and C-band staining showed marking in a terminal position on the long arm of a pair of subtelocentric chromosomes. The restriction enzyme AluI produced a linear differentiation similar to C-banding. This revised version was published online in July 2006 with corrections to the Cover Date.     

Monogeneans of the catfish Pimelodus blochii Valenciennes (Siluriformes: Pimelodidae) from the Brazilian Amazon,with a description of a new species of Ameloblastella Kritsky,Mendoza-Franco & Scholz, 2000 (Monogenea: Dactylogyridae)

Ameloblastella amazonica n. sp. (Monogenea: Dactylogyridae) collected on the gills of Pimelodus blochii Valenciennes (Siluriformes: Pimelodidae) from Rivers Acre and Iaco, State of Acre (Brazil) is described. The new species differs from the congeners mainly by the morphology of the dorsal bar, i.e. slightly U-shaped bearing a posteriorly directed flap, arising from the anterior edge of its middle third. The most morphologically similar congeners, A. paranaensis (França, Isaac, Pavanelli & Takemoto, 2003) and A. satoi Monteiro, Kritsky & Brasil-Sato, 2010, resemble A. amazonica n. sp. regarding the general structure of the copulatory complex; however, besides other features, they also differ from the new species because their hooks are similar in size (vs hooks with three different sizes). In addition to the dorsal bar lacking a flap, A. amazonica n. sp. can be differentiated from all congeners based on the combination of the following features: size of hooks (one or two different sizes), shape of the dorsal bar (other than slightly U-shaped), anchor points largely passing the level of superficial root (vs not or slightly passing it), number of MCO rings (other than 3–4) and structure of the articulation between the MCO base and the accessory piece (other than thick, medium-sized, smooth and tubular). Demidospermus leptosynophallus Kritsky & Gutierrez, 1998 and Scleroductus yuncensi Jara & Cone, 1989 were also found infesting P. blochii, both representing new host and locality records.

     

Diet of the brown hare (Lepus europaeus) and food availability in northern Patagonia (Mendoza, Argentina)

The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its introduction at the end of the 19th century. Studies on hare feeding ecology are important to evaluate a potential competition with domestic and native wild herbivores. This study analyses the brown hare diet in relation to food availability, and dietary overlaps with several herbivores in northern Patagonia. Food availability was estimated by point-quadrat transects, and hare diet by microhistological analysis of faeces, carried out in five habitats in five seasonal samplings. Significant differences were detected by Kruskall–Wallis ANOVA with multiple comparisons by Tukey test. Feeding selection was detected by χ² test, and dietary preferences by the confidence interval of Bailey. Grasses and chamaephytes were the most available plant categories, with Stipa, Panicum and Acantholippia as main species. Grasses and phanerophytes were the main dietary categories, including Poa, Panicum, Bromus, Adesmia and Prosopidastrum. The phanerophytes Prosopidastrum and Ephedra were more eaten in winter, when the main food item (Poa) presented lower availability. A higher dietary proportion of the chamaephyte Acantholippia occurred in rocky habitats, where the coarse dominant grasses were always avoided. Hares shared most food items with several wild and domestic herbivores in northern Patagonia. The lack of preference for forbs differentiates brown hares from other herbivores. However, hares exhibited important dietary similarities with plain and mountain vizcachas, goats and horses, and an interspecific competition for food is highly probable.     

Cytogenetic characterization of F1, F2 and backcross hybrids of the Neotropical catfish species Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Pimelodidae, Siluriformes)

The cytogenetic characteristics of Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum and their F1, F2 and backcross hybrids were assessed by using chromosome banding techniques. The diploid number of 56 chromosomes was constant in all species and lineages, with a karyotypic formula containing 20 metacentric, 12 submetacentric, 12 subtelocentric and 12 acrocentric chromosomes. Nucleolar organizer regions (NORs) were identified in two subtelocentric chromosomes in the parents and hybrids, with partial nucleolar dominance in F1 and F2 specimens. Heterochromatic blocks were detected in the terminal and centromeric regions of some chromosomes in all individuals. For parental and hybrid lineages, 18S ribosomal clusters corresponding to NORs and 5S ribosomal genes were identified in distinct pairs of chromosomes. The striking conservation in the chromosomal macrostructure of the parental species may account for the fertility of their F1 hybrids. Similarly, the lack of marked alterations in the chromosomal structure of the F1 hybrids could account for the maintenance of these features in post-F1 lineages.     

The ultrastructure of Sorubim lima (Teleostei, Siluriformes, Pimelodidae) spermatogenesis: premeiotic and meiotic periods

The ultrastructure of Sorubim lima spermatogenesis during the premeiotic and meiotic periods was studied. Our observations showed that the germ cells in the cysts are connected by cytoplasmic bridges and the mitotic and meiotic divisions are slightly asynchronous. The first and the last spermatogonial generations differ in the cellular and nuclear volume, nucleolus, chromatin condensation, distribution, size, density, and shape of the mitochondria, presence of 'lamellae anulata', amount and dimension of the 'nuages', and movement of the centrioles. In addition to the nuclear prophase structures, the spermatocyte I shows changes in all other cellular organelles and elongated vesicles appear in the cytoplasm. The accentuated cytoplasmic density and thickened walled vesicles are morphological characteristics that differentiate spermatocytes II from the other germ cells in the cysts of Sorubim lima testis.     

Habitat and Population Data of Troglobitic Armored Cave Catfish, Ancistrus Cryptophthalmus Reis, 1987, from Central Brazil (Siluriformes: Loricariidae)

Population ecology of the troglobitic armored catfish, A. cryptophthalmus, from caves in São Domingos karst area of central Brazil, was studied in a two-census capture-mark-recapture study carried out during the dry season of 1999. Like many loricariids, including epigean Ancistrus catfishes from that area, A. cryptophthalmus is a typical bottom-dweller with a strong preference for rocky substrates in fast-flowing stream sectors. Relatively high population densities, when compared to other cavefishes, were recorded in the studied cave sections: 0.9 individuals m^–2 in Angélica Cave and 0.5 individuals m^–2 in Passa Três Cave. Passa Três Stream is a small tributary of the São Vicente Cave system, and the estimated population for Passa Três Cave (ca. 2000 m long) is around 1000 individuals. On the other hand, the large Angélica Cave Stream (8 km long) harbors a very large population, conservatively estimated at 20 000 individuals. No fish movements of distances longer than 100 m were recorded in the 40-day period. In Passa Três Cave, a few movements of distances up to 60 m were detected. Proportion of mature females in Angélica Cave was higher than in Passa Três Cave, possibly reflecting a greater food availability in the first cave. Mean individual growth rates in Angélica Cave (1.35 mm month^–1 for size class <41 mm SL, 0.17 mm month^–1 for size class >41 mm SL) point to relatively high longevities, possibly attaining 15 years.     

Diet of wild chimpanzees (Pan troglodytes verus) at Mt. Assirik,Senegal: I. Composition

The composition of the diet of a savanna-living population of wild chimpanzees (Pan troglodytes verus) at Mt. Assirik in Senegal is presented. The study site had a prolonged dry season, high temperatures, and vegetation dominated by grasses. Data came from direct observation, fecal specimens, and feeding traces; thus, strict criteria for acceptance of the indirect data were specified. Composition of diet was given in terms of species and family of prey, parts eaten, life-form, type of habitat, and criteria for inclusion. Forty-three species of plants with 60 parts were eaten; mostly fruits, from trees, in woodland. Nine species of animal prey were eaten, mostly social insects. An additional 41 species of plants with 53 parts were classed as likely to be eaten by chimpanzees, mostly on the grounds of their being eaten by sympatric anthropoids. Overall, the diet of the apes at Mt. Assirik resembles that of this species elsewhere in Africa, but the size of the dietary repertoire seems small and the proportion of low-quality foodstuffs high. The latter are mostly time-consuming to collect or tedious to obtain or process, and include underground storage organs.     

Nutritional Aspects of Western Lowland Gorilla (Gorilla gorilla gorilla) Diet During Seasons of Fruit Scarcity at Bai Hokou,Central African Republic

Traditionally, gorillas were classified as folivores, yet 15 years of data on western lowland gorillas (Gorilla gorilla gorilla) show their diet to contain large quantities of foliage and fruit, and to vary both seasonally and annually. The consumption of fruit by gorillas at Bai Hokou, Central African Republic, is correlated with rainfall and ripe fruit availability (Remis, 1997a). We investigated the nutritional and chemical content of gorilla foods consumed at Bai Hokou during two seasons of fruit scarcity as measured by phenological observations and compared our findings with the nutrient content of gorilla foods at other African sites. We conclude that during lean times, Bai Hokou gorillas consumed fruits with higher levels of fiber and secondary compounds than those of other populations of western lowland or mountain gorillas. Conversely, leaves consumed by Bai Hokou gorillas were relatively low in fiber and tannins. Bai Hokou gorillas appeared to meet their nutritional needs by eating a combination of fruit and foliage. They ate fruits comparatively high in secondary compounds and fiber when necessary. While gorillas are selective feeders, wherever and whenever preferred foods are scarce, their large body size and digestive anatomy enable them to consume and process a broader repertoire of foods than smaller bodied-apes.     

Ontogenetic shift in mouth opening mechanisms in a catfish (Clariidae, Siluriformes): a response to increasing functional demands

During ontogeny, larval fish have to deal with increasing nutritional and respiratory demands as they grow. As early ontogeny is characterized by an increasing complexity of moving structural elements composing a fish skull, some constraints will have to be met when developing mechanisms, which enable feeding and respiration, arise at a certain developmental stage. This article focuses on the presence/absence of a possible functional response in mouth opening during ontogeny in Clarias gariepinus. Some reflections are given, based on morphological data, as well as related function-analysis data from the literature. Starting shortly after hatching, a total of up to five different mouth opening mechanisms may become functional. Of these, three may remain functional in the adult. As could be expected, the apparatuses that enable these mechanisms show an increase in complexity, as well as a putative improvement in mouth opening capacity. Initially, two consecutive mechanisms may allow a restricted depression of the lower jaw (both passively and actively). Synchronously, two more mechanisms may arise, which involve the coupling of the hyoid depression to the mouth opening. At about 11 mm SL a fifth mechanism becomes established, better known as the opercular mouth opening mechanism. An overlapping chronology of functionality of the different mechanisms, as well as differences in efficiencies, could be an indication of the absence of a true critical period in C. gariepinus (at least in relation to mouth opening), as well as the possible presence of a shift in feeding type. Finally, the coupling of the chronology of the shift in mouth opening mechanisms and several morphological, behavioral, and physiological changes during ontogeny, related to feeding and respiration, make it possible to distinguish five important phases in the early life history of C. gariepinus.     

Morphogenia: a new genus of the Neotropical tribe Jubini (Coleoptera,Staphylinidae, Pselaphinae) from the Brazilian Amazon

A new genus and species of the large Neotropical pselaphine tribe Jubini is described from Manaus, Brazil, based on material preserved in the Natural History Museum, London. Morphogenia struhligen. et sp. n. represents the possible sister taxon of the abundant and speciose genus Barrojuba Park, sharing with it the putatively derived condition of anterolaterally shifted vertexal foveae, producing a smoothly convex vertex devoid of fovea or sulci. However, unlike Barrojuba, Morphogenia retains a plesiomorphic antebasal sulcus on the pronotum in both sexes, and additionally lacks elaborate abdominal fovea-like pockets and teeth on the lateral margins of the pronotum that are typical of Barrojuba. The genus is also unusual among jubine genera in lacking the characteristic V- or Y-shaped gular carina. In contrast to the commonly-collected Barrojuba, specimens of Morphogenia are absent in extensive jubine collections housed in museums in the United States, indicating that the new taxon may be relatively scarce or localised.     

Seasonal growth and life history of the catfish Calophysus macropterus (Lichtenstein, 1819) (Siluriformes: Pimelodidae) from the Amazon floodplain

The objective was to study seasonal aspects of the piracatinga catfish ( Calophysus macropterus ) growth and its relationship with the flood pulse. Analyzed from June 1997 to May 1998 were 446 specimens from the Amazon River. Using the period regression model with several biometric indexes gave the following results: two periods of low growth were identified in the vertebrae of C. macropterus , the first during falling water (August) and the second during rising water (January), using marginal increment analysis (MIA). This pattern was also observed in the annual variation of the regression coefficient of the length–weight relationship ( b ), and Feeding Index (FI), but an inverse relationship was observed with the Maturity Index (MI). These results suggest that reproduction occurs from January to February in the rising water season, when C . macropterus reaches sexual maturity at 1.4 and 1.5 of age for females and males, respectively. The parameters of Bertalanffy's model were SL = 40.05[1−e^{−0.44(t−0.37)}] for females and SL = 41.9[1−e^{−0.42(t−0.36)}] for males. Natural mortality was high (♀:0.42–♂:0.40) and longevity low (♀:6.8–♂:7.1 years). The present study demonstrates that seasonal growth in C. macropterus is correlated with the flood pulse, especially in periods of rising and falling waters. These results, analyzed by the periodic regression model, showed that reproduction, migration or changes in feeding behavior have relationships with annulus formation in hard structures in this species. All quantitative indexes show clear seasonal variation to be correlated with river water level fluctuations.     

Amblyceps waikhomi,a New Species of Catfish (Siluriformes: Amblycipitidae) from the Brahmaputra Drainage of Arunachal Pradesh,India

Amblyceps waikhomi sp. nov. is described from the Nongkon stream which drains into the Noa Dehing River, a tributary of the Brahmaputra River, in Arunachal Pradesh, India. The new species can be distinguished from congeners (except A. torrentis) in having a deeper body depth at anus. It further differs from congeners (except A. mangois and A. serratum) in having fewer vertebrae, from A. mangois in lacking (vs. having) strongly-developed projections on the proximal lepidotrichia of the median caudal-fin rays, and in having a longer, wider, and deeper head; and from A. serratum in having a posteriorly smooth (vs. with 4–5 serrations) pectoral spine, and unequal jaw length (lower jaw longer and weakly-projecting anteriorly vs. equal upper and lower jaws). It additionally differs from A. murraystuarti, A. torrentis, A. apangi, A. laticeps, and A. cerinum in having a deeply forked (vs. emarginate or truncate) caudal fin. This species is the seventh amblycipitid species known to occur in the Ganga-Brahmaputra River system.     

Bioacoustic variation of swimbladder disturbance sounds in Neotropical doradoid catfishes (Siluriformes: Doradidae,Auchenipteridae): Potential morphological correlates

Swimbladder disturbance sounds of doradoid catfishes (Doradidae and Auchenipteridae) demonstrated striking waveform and spectrographic variation.We surveyed sounds of 25 doradoid species in 20 genera comparing these to sounds of four vocal outgroup catfish families.Sounds were either continuous waveforms (lacking interpulses) or pulsed (groups of pulses repeated at fixed temporal intervals).This is the first evidence for swimbladder calls with fixed interpulse patterns in catfishes.Vocal mechanism components that were similar between doradids and auchenipterids included:swimbladder shape,swimbladder dimensions and sonic muscle-somatic index.Morphological traits that showed variation among taxa and were evaluated for potential correlates of call diversity are:1) diverticula (marginal outpocketings of the swimbladder with no connection to inner ear) and 2) elastic spring apparatus Millerian rami (ESA-Mr).Within the doradid subfamilies and within the Auchenipteridae most species differed significantly in dominant frequency with frequency ranges overlapping to some extent for most.Doradid swimbladder diverticula did not explain dominant frequency variation within the doradoid superfamily.Some doradids with conical ESA-Mr had the highest dominant frequency sounds.Auchenipterids included both relatively lower and higher dominant frequency sound producers but lacked diverticula and had discoidal ESA-Mr.Comparing a phylogeny of doradoid genera with outgroup taxa,we infer that complex diverticula and conical ESA-Mr are derived characters within the Doradidae.Species representing outgroup families produced either continuous lower dominant frequency sounds (aspredinids,mochokids and pseudopimelodids) or pulsed higher dominant frequency sounds (pimelodids) [Current Zoology 58 (1):171-188,2012].     

Differences in pectoral fin spine morphology between vocal and silent clades of catfishes (Order Siluriformes): Ecomorphological implications

Stridulatory sound-producing behavior is widespread across catfish families, but some are silent. To understand why, we compared spine morphology and ecotype of silent and vocal clades. We determined vocal ability of laboratory specimens during disturbance behavior. Vocal families had bony (not flexible or segmented) spines, well-developed anterior and/or posterior serrations, and statistically significantly longer spines. We compared morphology of the proximal end of the pectoral spine between vocal and silent species. For vocal taxa, microscopic rounded or bladed ridges or knobs were present on the dorsal process. Most silent species had reduced processes with exclusively smooth, convoluted, or honeycombed surfaces very similar to spine-locking surfaces, or they had novel surfaces (beaded, vacuolated, cobwebbed). Most callichthyids had ridges but many were silent during disturbance. All doradid, most auchenipterid and most mochokid species were vocal and had ridges or knobs. Within the Auchenipteridae, vocal species had spines with greater weight and serration development but not length. Silent auchenipterids had thin, brittle, distally segmented spines with few microscopic serrations on only one margin and a highly reduced dorsal process lacking any known vocal morphology. Silent auchenipterids are derived and pelagic, while all vocal genera are basal and benthopelagic. This is the first phylogenetic evidence for stridulation mechanism loss within catfishes. Phylogenetic mapping of vocal ability, spine condition, and ecotype revealed the repeated presence of silence and vocal taxa, short and long spines, and ecotype shifts within clades. The appearance and loss of vocal behavior and supporting morphologies may have facilitated diversification among catfishes [Current Zoology 56 (1): 73-89 2010].     

Sperm ultrastructure and a new type of spermiogenesis in two species of Pimelodidae, with a comparative review of sperm ultrastructure in Siluriformes (Teleostei: Ostariophysi)

During spermiogenesis, the spermatids of the pimelodid species Pimelodus maculatus and Pseudoplatystoma fasciatum show a central flagellum development, no rotation of the nucleus, and no nuclear fossa formation, in contrast to all previously described spermatids of Teleostei. These characteristics are interpreted as belonging to a new type of spermiogenesis, named here type III, which is peculiar to the family Pimelodidae. In P. maculatus and P. fasciatum, spermatozoa possess a spherical head and no acrosome; their nucleus contains highly condensed, homogeneous chromatin with small electron-lucent areas; and a nuclear fossa is not present. The centriolar complex lies close to the nucleus. The midpiece is small, has no true cytoplasmic channel, and contains many elongate and interconnected vesicles. Several spherical to oblong mitochondria are located around the centriolar complex. The flagellum displays the classical axoneme (9+2) and no lateral fins. Only minor differences were observed among the pimelodid species and genera. Otherwise, spermiogenesis and spermatozoa in the two species of Pimelodidae studied exhibit many characteristics that are not found in other siluriform families, mainly the type III spermiogenesis.