Molecular phylogeny of Moenkhausia (Characidae) inferred from mitochondrial and nuclear DNA evidence

Moenkhausia is one of the most speciose genera in Characidae, currently composed of 75 nominal species of small fishes distributed across South American hydrographic basins, primarily the Amazon and Guyanas. Despite the large number of described species, studies involving a substantial number of its species designed to better understand their relationships and putative monophyly are still lacking. In this study, we analysed a large number of species of Moenkhausia to test the monophyly of the genus based on the phylogenetic analysis of DNA sequences of two mitochondrial and three nuclear genes. The in‐group included 29 species of Moenkhausia, and the out‐group was composed of representatives of Characidae and other members of Characiformes. All species of Moenkhausia belong to the same clade (Clade C); however, they appear distributed in five monophyletic groups along with other different genera, which means that Moenkhausia is polyphyletic and indicates the necessity of an extensive revision of the group.     

Phylogenetic study of the Characinae (Teleostei: Characiformes: Characidae)

The Characinae is a subunit of the Characidae of special significance in including Charax, the type genus of the family and the order Characiformes. Twelve genera and 79 species have been traditionally assigned to the Characinae, but the subfamily still lacks a phylogenetic diagnosis. Herein, a data matrix including 150 morphological characters and 64 taxa (35 species representing all genera of the Characinae and 29 included in other lineages within the Characiformes) was submitted to two cladistic analyses that differ in the inclusion/exclusion of Priocharax due to the difficulty of coding most of the character states in the miniature species of this genus. Both analyses resulted in a non‐monophyletic Characinae and this subfamily is herein restricted to only seven of the original 12 genera forming the clade (Phenacogaster((Charax Roeboides)(Acanthocharax(Cynopotamus(Acestrocephalus Galeocharax))))), which is supported by ten non‐ambiguous synapomorphies and is more closely related to other genera of the Characidae than those traditionally placed in the subfamily. A second clade includes the members of the tribe Heterocharacini (Lonchogenys(Heterocharax Hoplocharax)) as the sister‐group of Gnathocharax, supported by seven non‐ambiguous synapomorphies. This clade is more closely related to a taxon formed by Roestes and Gilbertolus based on seven non‐ambiguous synapomorphies. Results do not corroborate a close relationship between Roestes–Gilbertolus and the Cynodontinae. Inclusion of the genus Priocharax suggests that it is related more closely to the Heterocharacini, but the profound modifications in its anatomy possibly related to ontogenetic truncations obscure a better understanding of its relationships. A new classification of the Characinae and the Heterocharacinae is proposed. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 809–915.     

Patterns of herbivory on Passiflora leaf tissues and species by generalized and specialized feeding insects

Abstract.

• 1 The feeding patterns of specialized (Heliconius butterflies) and generalized (the grasshopper, Osmilia flavolineata) herbivores on leaf age classes and species of neotropical vines in the genus Passiflora are compared by offering them leaf discs in choice experiments.
• 2 Heliconius larvae selected young meristematic leaves over medium aged and mature leaves of Passiflora auriculata on which to feed.
• 3 Adults of O. flavolineata consumed more young leaves of P. pittieri from an array of different ages of leaf tissue, but showed no preference for young over mature leaves of P. tetrastylus or P. data.
• 4 In choice tests conducted with medium aged leaves of four species of Passiflora, O. flavolineata selected P. tetrastylus over P. pittieri and P. vitifolia, which were consumed more than P. alata.
• 5 P. alata, which was avoided by O. flavolineata in feeding trials, was the only abundant Passiflora in neotropical habitats where generalized herbivores (grasshoppers and katydids) were common.
• 6 Our results suggest that Passiflora species in forest habitats where some generalized herbivores are rare have fewer chemical defences, but retain physical defences (tough leaves and hooked trichomes) rendering them unpalatable to specialized herbivores like the larvae of Heliconius butterflies.

     

Length–weight relationship of two restricted‐range fish species from central Brazil highlands: Hyphessobrycon coelestinus Myers, 1929 and Hasemania crenuchoides Zarske & Géry, 1999 (Characidae: Characiformes)

This study presents length‐weight relationships (LWR) for two species of the family Characidae (Characiformes), Hyphessobrycon coelestinus and Hasemania crenuchoides, captured in the central highlands of Brazil.     

Complex spatial structure in a population of <Emphasis Type="Italic">Didymopanax pittieri</Emphasis>, a tree of wind-exposed lower montane rain forest

Didymopanax pittieri is a common shade-intolerant tree colonizing treefall gaps in the elfin forests on windswept ridgecrests in the lower montane rain forests of the Cordillera de Tilarán, Costa Rica. All D. pittieri taller than >0.5 m in a 5.2-ha elfin forested portion of a gridded study watershed in the Monteverde Cloud Forest Preserve were located, mapped, and measured. This local population of D. pittieri is spatially inhomogeneous, in that density increases with increasing wind exposure; D. pittieri are more abundant near ridge crests than lower on windward slopes. The important and ubiquitous phenomenon of spatial inhomogeneity in population density is addressed and corrected for in spatial analyses by the application of the inhomogeneous version of Ripley’s K. The spatial patterns of four size classes of D. pittieri (<5 cm dbh, 5–10 cm dbh, 10–20 cm dbh, and >20 cm dbh) were investigated. Within the large-scale trend in density driven by wind exposure, D. pittieri saplings are clumped at the scale of treefall gaps and at the scale of patches of aggregated gaps. D. pittieri 5–10 cm dbh are randomly distributed, apparently due to competitive thinning of sapling clumps during the early stages of gap-phase regeneration. D. pittieri larger than 10 cm dbh are overdispersed at a scale larger than that of patches of gaps. Natural disturbance can influence the distribution of shade intolerant tree populations at several different spatial scales, and can have discordant effects at different life history stages.     

Comparative analysis of gonadal morphology in six fish species of the Incertae Sedis genera in Characidae of occurrence in the São Francisco River Basin,Brazil

Martins, Y.S., Arantes, F.P., Sato, Y., dos Santos, J.E., Rizzo, E. and Bazzoli, N. 2012. Comparative analysis of gonadal morphology in six fish species of the Incertae Sedis genera in Characidae of occurrence in the São Francisco River Basin, Brazil. —Acta Zoologica (Stockholm) 93 : 48–56. This study presents a comparative analysis aiming to show the remarkable differences found in gonad morphology between six fish species from the genera Incertae Sedis in the Characidae family. Maturing ovaries of Astyanax fasciatus presented grayish color whilst the other species’ were yellowish in color. The cortical alveoli of the analyzed species are small (5.20 ± 1.44–8.28 ± 2.02 μm) and are formed by various discontinuous layers of vesicles except in the Bryconops affinis, where they are large (12.87 ± 2.41 μm) and form various continuous layers of vesicles. The pellucid zone is thin and varies from 2.44 ± 0.90 to 5.79 ± 1.90 μm and is thickest in B. affinis (10.57 ± 2.08 μm). Folds in the pellucid zone were observed in Astyanax bimaculatus, A. fasciatus, Hemigrammus marginatus, and Moenkhausia costae. The follicular cells of B. affinis are columnar (28.19 ± 13.71 μm), while they are squamous in other species (1.52 ± 0.64–2.12 ± 0.78 μm). This study showed that the morphologic and biometric characteristics of the B. affinis vitellogenic oocytes are statistically different than the analyzed other ones Incertae Sedis of the Characidae family. In advanced maturing testis of A. bimaculatus and A. fasciatus, the spermatozoa were embedded in acidophilic secretion which was gradually reabsorbed in the seminiferous tubules when males were partially spent.     

Hyphessobrycon platyodus (Teleostei: Characiformes), a new species from the Rio Madeira basin,Brazil, with comments on how multicuspid teeth relate to feeding habits in Characidae

A new species of Hyphessobrycon is described from the Rio Juma, a tributary of the lower Rio Aripuanã–Rio Madeira basin, Amazonas, Brazil. Hyphessobrycon platyodus can be distinguished from its congeners by the: presence of an elongated dorsal fin in adult males, 25–28 branched anal‐fin rays and absence of dark blotches from the dorsal fin and caudal peduncle. The presence of multicuspid teeth in species of Characidae and its relation with feeding habits are briefly commented on.     

Morphology,molecules and the phylogeny of Characidae (Teleostei,Characiformes)

This is the most comprehensive phylogenetic analysis of the Characidae to date and the first large-scale hypothesis of the family, combining myriad morphological data with molecular information. A total of 520 morphological characters were analysed herein, of which 98 are newly defined. Among the analysed taxa, 259 species were coded by examining specimens, three fossil species were coded from the literature, one species was coded almost completely from published figures, 122 were partially coded from the literature, and 88 were analysed exclusively from molecular data. The total number of species in the analysed dataset is 473. Analyses were made by parsimony under equal and extended implied weighting with a broad range of parameters. The final hypothesis was selected using a stability criterion that chooses among the most parsimonious trees of all searches. It was found by weighting molecular characters with the average homoplasy of entire partitions (markers). The resulting hypothesis is congruent with previous molecular-based phylogenies of the family. The Characidae are monophyletic, with four main clades: the Spintherobolinae new subfamily; an expanded Stethaprioninae including the Grundulini, Gymnocharacini, Rhoadsiini and Stethaprionini; the Stevardiinae; and a clade composed of the Aphyocharacinae, Characinae, Cheirodontinae, Exodontinae and Tetragonopterinae. Also, a stem Characidae was found, as formed by the Eocene–Oligocene genera †Bryconetes and †Paleotetra as successive sister groups of extant members of the family. A subfamilial classification is proposed, but deep changes in the systematics that are beyond the scope of this study are still needed to classify the Characidae into monophyletic genera.     

Interspecific variation of ontogeny and skull shape among porpoises (Phocoenidae)

All extant members of Phocoenidae (porpoises) have been characterized as pedomorphic based on skeletal characters. To investigate the ontogenetic background for pedomorphosis and assess interspecific differences in ontogeny among phocoenids, samples of the six extant species were compared in terms of development of both epiphyseal and cranial suture fusion. Across all species, full maturity of the vertebral column was rare. Vertebral epiphyseal development did not progress so far in most Phocoena phocoena as in Phocoenoides dalli and Phocoena dioptrica. P. phocoena, Phocoena spinipinnis, Ph. dalli, and P. dioptrica, for which large series were available, were further compared in terms of ontogeny of cranial shape by three‐dimensional geometric morphometrics. Ph. dalli and P. dioptrica generally showed further development of cranial sutures than the other species. Postnatal skull shape development was similar for all species studied; the majority of interspecific shape differences are present at parturition. Smaller species had a higher rate of shape development relative to growth in size than Ph. dalli and P. dioptrica, but they still showed less allometric development due to less postnatal growth. Interspecific shape differences indicate phylogenetic relationships similar to that proposed based on morphology or convergent evolution of the two pelagic species, Ph. dalli and P. dioptrica, under the scenarios suggested by recent molecular studies. A shape trend coinciding with habitat preference was detected; in species with pelagic preference the position and orientation of the foramen magnum aligned the skull with the vertebral column; the rostrum showed less ventral inclination, and the facial region was larger and more concave in lateral aspect. J. Morphol., 2011. © 2010 Wiley‐Liss, Inc.     

Photosynthetic and growth responses of three freshwater algae to phosphorus limitation and daylength

1. Three common species of freshwater phytoplankton, the diatom Nitzschia sp., green alga Sphaerocystis schroeteri and cyanobacterium Phormidium luridum, were grown under contrasting daylengths [18 : 6 h light : dark cycles (LD) versus 6 : 18 h LD] and phosphorus (P) regimes (P‐sufficient versus 1 μm P). The rates of growth and photosynthesis, as well as growth efficiencies and pigment concentrations, were compared among treatments. 2. The growth and photosynthetic parameters of the three species depended on both P status and daylength in a species‐specific way. The responses to P limitation depended on daylength and, conversely, the responses to daylength depended on P status. 3. Growth rates and the maximum rates of photosynthesis (P_max) of all species decreased under P limitation under both light regimes. However, the decrease of P_max because of P limitation was greater under long daylength. The P_max of the green alga S. schroeteri decreased the most (ca. sixfold) under P limitation compared with the other two species. The photosynthesis saturation parameter I_k also decreased under P limitation; the decline was significant in Nitzschia and Sphaerocystis. P‐limitation significantly increased photoinhibition (β) in Nitzschia and Sphaerocystis, but not in Phormidium. The excess photochemical capacity (the ratio of the maximum photosynthesis rate to the photosynthesis rate at the growth irradiance), characterising the ability to utilise fluctuating light, was significantly lower under P limitation. 4. The growth efficiency (growth rate normalised to daylength) declined with increasing daylength in all species. Under short daylength the cyanobacterium Phormidium had the lowest growth efficiency of the three species. 5. The cellular chlorophyll a concentration in both Nitzschia and Sphaerocystis was significantly higher under short daylength, but only under P‐sufficient conditions. In Nitzschia, under short daylength, P‐limitation significantly decreased cellular chlorophyll concentration. In contrast, P‐limitation increased cellular chlorophyll concentration in Sphaerocystis, but under long daylength only. The ratio of chlorophyll a to b in the green alga also declined under short daylength and under P‐limited conditions.     

Moenkhausia celibela: a new species from the Amazon basin,Brazil (Characiformes: Characidae)

A new species of Characidae, Moenkhausia celibela, is described from the Rio Amazonas at Santarém, Rio Maraú, several localities in the Rio Tapajós, Rio Curuá‐Una, Rio Xingu and Rio Jari, all from the Amazon basin, Brazil. The new species is distinguished from its congeners, except species included in Géry's 1992 Moenkhausia lepidura group, by presenting a dark blotch on the upper caudal‐fin lobe, and the lower lobe is hyaline or light grey. Moenkhausia celibela is distinguished from the species of the M. lepidura group by the absence of a humeral spot and the presence of a roughly triangular and dark spot at the caudal‐fin base, extending posteriorly along the middle caudal‐fin rays, and distinctly separate from the spot on the upper caudal‐fin lobe.     

Morphology, osteology and reductions in the ontogeny of the scaleless characid Gymnocharacinus bergi

The aim of this study was to analyse cartilage formation and ossification during the early life history of the relic fish Gymnocharacinus bergi. Additionally, changes associated with feeding and swimming were taken into account while considering the origin of the morphological reductions described for adult G. bergi that sets the species apart from the rest of the Characidae. During the ontogeny of G. bergi, pre‐metamorphic larvae have a subventral mouth, allowing benthivorous feeding. During metamorphosis, the mouth shifts to a terminal position, teeth change to multicuspidate, and the short, simple gut develops a loop and pyloric caecae. Juveniles shift their diet to feed on periphytic algae. Scale disappearance in juveniles and adults involves the cessation of scale growth and a rapid re‐absorption process. Several situations differ from the other species of this family: (a) the rhinosfenoides and the uroneural 2 never appear, even not as cartilaginous pieces, (b) the fourth basibranchial never undergoes ossification, (c) pseudourostyle, uroneural 1 and extrascapulae are reduced in adults, (d) infraorbitals are also reduced in size and number in adults, (e) scales form during metamorphosis but disappear during the juvenile and adult period. These differences are considered to be a consequence of low interspecific competition, low predation and small population size, allowing regression phenomena.     

Isolation and characterization of microsatellite loci in Piaractus mesopotamicus and their applicability in other Serrasalminae fish

The subfamily Serrasalminae (Characidae, Teleostei) is an endemic Neotropical group of fishes distributed along the Amazon, Paraná‐Paraguay and Orinoco Basins. The pacu (Piaractus mesopotamicus) is found in all major rivers that comprise the Pantanal of Mato Grosso. In order to investigate population genetic structure within the group, an enriched microsatellite library was constructed. Eight polymorphic were loci screened, with an average of 6.5 alleles per locus. Five loci exhibited greater than 60% heterozygosity. Additionally, a high level of cross‐species amplification was obtained.     

Ultrasonographic monitoring of fetal development in unrestrained bonobos (Pan paniscus) at the Milwaukee County Zoo

The bonobo, Pan paniscus, is one of the most endangered primate species. In the context of the Bonobo Species Survival Plan^®, the Milwaukee County Zoo established a successful breeding group. Although the bonobo serves as a model species for human evolution, no prenatal growth curves are available. To develop growth graphs, the animals at the Milwaukee County Zoo were trained by positive reinforcement to allow for ultrasound exams without restraint. With this method, the well being of mother and fetus were maintained and ultrasound exams could be performed frequently. The ovulation date of the four animals in the study was determined exactly so that gestational age was known for each examination. Measurements of biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL) were used to create growth curves. Prenatal growth of P. paniscus was compared with the data of humans and the common chimpanzee, P. troglodytes. With respect to cranial structures, such as BPD and HC, humans have significant acceleration of growth compared with P. paniscus and P. troglodytes. In P. paniscus, growth of AC was similar to HC throughout pregnancy, whereas in humans AC only reaches the level of HC close to term. Growth rate of FL was similar in humans and the two Pan species until near day 180 post‐ovulation. After that, the Pan species FL growth slowed compared with human FL. The newly developed fetal growth curves of P. paniscus will assist in monitoring prenatal development and predicting birth dates of this highly endangered species. Zoo Biol 30:241–253, 2011. © 2010 Wiley‐Liss, Inc.     

Bat visits to Marcgravia pittieri and notes on the inflorescence diversity within the genus Marcgravia (Marcgraviaceae)

We report bat visits to the inflorescences of Marcgravia pittieri. The animals were videotaped visiting the nectaries of the inflorescences in short hovering flight. Nectarivorous bats caught in front of the inflorescences were Anoura cultrata and Hylonycteris underwoodi (both Phyllostomidae: Glossophaginae). Furthermore, we provide a short overview on inflorescence architecture within the genus Marcgravia with a special focus on functional morphology in chiropterophilous species.     

Gill‐derived glands in species of Astyanax (Teleostei: Characidae)

The presence of a gill‐derived gland is herein reported for the first time in males of species of Astyanax and related genera; they are described through histological cuts and SEM. The gill‐derived glands described for the Characidae, when fully developed, present a similar structure in different species. The main external feature of gill‐derived glands is the fusion of anteriormost gill filaments on the ventral branch of first gill arch. This fusion is caused by squamous stratified epithelial tissue that covers adjacent filaments, forming a series of chambers. In the region where the gill‐derived gland develops, the secondary lamellae of the gill filaments are much reduced or completely atrophied being characterized by the presence of glandular cells forming nests.     

Nutrient limitation in boreal rich‐fen vegetation: A fertilization experiment

Abstract. Rich‐fen vegetation influenced by hay‐making in the Sølendet Nature Reserve, Central Norway, was fertilized with N, P and K in a full‐factorial fertilization experiment to investigate the nutrient limitation of plant growth at both community and species levels. Above‐ground biomass, shoot density and nutrient concentration were measured in several species and groups of species at three sites after two years of fertilization. At the community level, the results indicate multiple limitation by N and P in the two least productive rich‐fen communities: one characterized by small sedges and herbs, and the other by high abundance of Menyanthes trifoliata and tall sedges. Increased nutrient availability had no effect on a more highly productive, tall‐growing, spring‐influenced community, indicating no nutrient limitation. The results at the species level correspond well with those at the community level, indicating multiple limitation by N and P in most of the dominant and sub‐dominant species. However, P seems to limit growth more than N in Succisa pratensis, and N seems to limit growth more than P in Carex panicea. Furthermore, Eriophorum angustifolium seems to be limited by K. The results did not show which nutrient limits the growth of Carex dioica, C. lasiocarpa and Trichophorum cespitosum. Indications that growth in low‐productive, boreal rich‐fen communities is generally limited by P was not confirmed.     

Mitogenome of Knodus borki (Cypriniformes: Characidae): genomic characterization and phylogenetic analysis

Background

The taxonomic status of Knodu in the family Characidae is not yet clear. This study aimed to address this by sequencing and annotating Knodu borki Zarske, 2008.

Materials and results

K. borki Zarske, 2008 was sequenced using a Hiseq platform and the complete mitogenome was assembled in SPAdes v3.15.2 and SOAPdenovo2 v.2.01. The mitogenome of K. borki from Guangzhou, the first sequenced species of the genus Knodu, is 16,837 bp in length and contains 13 protein-coding genes (PCGs), two ribosomal (r) RNAs, 22 transfer (t) RNAs, and one D-loop. Among these 37 genes, 28 are encoded by the heavy strand, while nine are encoded by the light strand. Twenty-one of the tRNAs can form typical cloverleaf secondary structures, except tRNA-Ser1, which lacks dihydrouridine arms. All PCGs have the same start codon (ATG), with the exception of COI (GTG). Four PCGs (ND1, ATP8, ND4L, and ND5) have TAA as the stop codon, ND6 has TAG as the stop codon, COI has AGG as the stop codon, and the remaining seven genes have incomplete stop codons of TA-/T-(ND2, COII, COIII, ND3, ND4, and Cyt b as T-, ATP6 as TA-). Phylogenetic analysis showed that K. borki belongs to the family Characidae.

Conclusions

Our findings demonstrate that K. borki belongs to the family Characidae, due to consistency with the morphological identification. This study provides molecular information for further research on the phylogeny of the genus Knodus and for analyses of the taxonomic status of Characidae.