Morphology, molecular phylogeny, and taxonomic inconsistencies in the study of Bradypus sloths (Pilosa: Bradypodidae)

This study focuses on morphological and molecular data analyses, misidentifications, and phylogenetic inconsistencies regarding Bradypus variegatus (the brown-throated sloth) and B. tridactylus (the pale-throated sloth). Misidentifications were recorded on 75 of 313 museum specimens of Bradypus. Almost 90% of the misidentified specimens were B. variegatus from north-central Brazil, erroneously attributed to B. tridactylus. These misidentified specimens are reported in taxonomic reviews as the southernmost records of B. tridactylus. A history of confusing nomenclature regarding sloth species exists, and these particular misidentifications could be attributable to the similarity in face and throat color between B. variegatus from north-central Brazil and B. tridactylus. The molecular phylogeny of morphologically confirmed sloth specimens exhibits 2 monophyletic lineages representing B. variegatus and B. tridactylus. The split time between these 2 lineages was estimated at 6 million years ago (mya), contradicting previous studies that estimated this divergence to be 0.4 mya. Taxonomic inconsistencies were detected when comparing the molecular phylogeny to previously published DNA sequences ascribed to B. tridactylus. Misidentification or introgression could underlie such phylogenetic incongruities. Regardless of their causes, these discrepancies lead to misstatements regarding geographic distribution, phylogeny, and taxonomy of B. variegatus and B. tridactylus.

Phylogeny of the Neotropical genus Acestrorhynchus (Ostariophysi: Characiformes) based on nuclear and mitochondrial gene sequences and morphology: A total evidence approach

Acestrorhynchus is the sole genus of the family Acestrorhynchidae which includes 14 species currently recognized as valid. Species of Acestrorhynchus comprise small-to-medium sized piscivorous fishes and have been traditionally grouped on the basis of well-defined color patterns. A recent phylogeny, based on morphological characters, could not resolve the phylogenetic affinities of A. heterolepis and the relationships among the species of the clade formed by A. abbreviatus, A. altus, A. falcatus, A. lacustris, and A. pantaneiro. The simultaneous analysis of two mitochondrial genes (16S and ATP synthase subunits 6 and 8) and one nuclear intron (S7) was able to resolve the latter clade, but the position of A. heterolepis remained unresolved. The combination of the molecular and morphological data sets in a total evidence analysis resulted in a well-resolved hypothesis regarding the phylogenetic relationships of Acestrorhynchus species. (C) 2009 Elsevier Inc. All rights reserved.

Morphology and phylogenetic relationships of a remarkable new genus and two new species of Neotropical freshwater stingrays from the Amazon basin (Chondrichthyes: Potamotrygonidae)

The morphology and phylogenetic relationships of a new genus and two new species of Neotropical freshwater stingrays, family Potamotrygonidae, are investigated and described in detail. The new genus, Heliotrygon, n. gen., and its two new species, Heliotrygon gomesi, n. sp. (type-species) and Heliotrygon rosai, n. sp., are compared to all genera and species of potamotrygonids, based on revisions in progress. Some of the derived features of Heliotrygon include its unique disc proportions (disc highly circular, convex anteriorly at snout region, its width and length very similar), extreme subdivision of suborbital canal (forming a complex honeycomb-like pattern anterolaterally on disc), stout and triangular pelvic girdle, extremely reduced caudal sting, basibranchial copula with very slender and acute anterior extension, and precerebral and frontoparietal fontanellae of about equal width, tapering very little posteriorly. Both new species can be distinguished by their unique color patterns: Heliotrygon gomesi is uniform gray to light tan or brownish dorsally, without distinct patterns, whereas Heliotrygon rosai is characterized by numerous white to creamy-white vermiculate markings over a light brown, tan or gray background color. Additional proportional characters that may further distinguish both species are also discussed. Morphological descriptions are provided for dermal denticles, ventral lateral-line canals, skeleton, and cranial, hyoid and mandibular muscles of Heliotrygon, which clearly corroborate it as the sister group of Paratrygon. Both genera share numerous derived features of the ventral lateral-line canals, neurocranium, scapulocoracoid, pectoral basals, clasper morphology, and specific patterns of the adductor mandibulae and spiracularis medialis muscles. Potamotrygon and Plesiotrygon are demonstrated to share derived characters of their ventral lateral-line canals, in addition to the presence of angular cartilages. Our morphological phylogeny is further corroborated by a molecular phylogenetic analysis of cytochrome b based on four sequences (637 base pairs in length), representing two distinct haplotypes for Heliotrygon gomesi. Parsimony analysis produced a single most parsimonious tree revealing Heliotrygon and Paratrygon as sister taxa (boot-strap proportion of 70%), which together are the sister group to a clade including Plesiotrygon and species of Potamotrygon. These unusual stingrays highlight that potamotrygonid diversity, both in terms of species composition and undetected morphological and molecular patterns, is still poorly known.

Ontogenetic Changes in the Bell Morphology and Kinematics and Swimming Behavior of Rowing Medusae: the Special Case of the Limnomedusa Liriope tetraphylla

Swimming animals may experience significant changes in the Reynolds number (Re) of their surrounding fluid flows throughout ontogeny. Many medusae experience Re environments with significant viscous forces as small juveniles but inertially dominated Re environments as adults. These different environments may affect their propulsive strategies. In particular, rowing, a propulsive strategy with ecological advantages for large adults, may be constrained by viscosity for small juvenile medusae. We examined changes in the bell morphology and swimming kinematics of the limnomedusa Liriope tetraphylla at different stages of development. L. tetraphylla maintained an oblate bell (fineness ratio approximate to 0.5-0.6), large velar aperture ratio (R(v) approximate to 0.5-0.8), and rapid bell kinematics throughout development. These traits enabled it to use rowing propulsion at all stages except the very smallest sizes observed (diameter = 0.14 cm). During the juvenile stage, very rapid bell kinematics served to increase Re sufficiently for rowing propulsion. Other taxa that use rowing propulsion as adults, such as leptomedusae and scyphomedusae, typically utilize different propulsive strategies as small juveniles to function in low Re environments. We compared the performance values of the different propulsive modes observed among juvenile medusae.

REDESCRIPTION OF APOSTOLEPIS LONGICAUDATA (SERPENTES: XENODONTINAE) WITH COMMENTS ON ITS HEMIPENIAL MORPHOLOGY AND NATURAL HISTORY

Apresentamos a redescricao da rara especie de serpent Apostolepis longicaudata Comes in Amaral coin base no exame do holotipo e em comparacoes com tres novos exemplares do Cerrado do Brasil Central. O trabalho inclui dados ineditos sobre a coloracao em vida, morfologia hemipeniana e historia natural. Dois especimes lineados previamente identificados como A. quinquelineata por outros autores sao redeterminados aqui como A. nelsonjorgei, que parece ser a unica especie do genero cujas contagens de subcaudais se sobrepoem as de A. longicaudata.

Morphology of terebelliform polychaetes (Annelida: Polychaeta: Terebelliformia), with a focus on Terebellidae

The morphology of terebelliform polychaetes was investigated for a phylogenetic study focused on Terebellidae. For this study, specimens belonging to 147 taxa, preferably type material or specimens from type localities or areas close to them, were examined under stereo, light and scanning electron microscopes. The taxa examined were 1 Pectinariidae, 2 Ampharetidae, 2 Alvinellidae, 8 Trichobranchidae, and 134 Terebellidae, which included 8 Polycirrinae, 15 Thelepodinae, and 111 Terebellinae. A comparison of the morphology, including prostomium, peristomium, anterior segments and lobes, branchiae, glandular venter, nephridial and genital papillae, notopodia and notochaetae, neuropodia and neurochaetae, and posterior end, was made of all the currently recognized families of terebelliform polychaetes, with special emphasis on Terebellidae. A discussion of the characters useful to distinguish between genera is given. This character set will be used in a subsequent phylogenetic study (Nogueira & Hutchings in prep.)

On spermiogenesis, sperm cell morphology and accompanying secretions of Copidognathus (Acari: Halacaridae)

The genus Copidognathus includes one-third of the species of Halacaridae described to date. This article describes spermiogenesis, sperm cell morphology and accompanying secretions from three species of Copidognathus. Initial spermatids have electron-dense cytoplasm with scattered mitochondria, a well-developed Golgi body, and nuclei with patches of heterochromatin. The cytoplasm and nuclei of these cells undergo intense swelling. The second spermatids are large electron-translucent cells, with small mitochondria in row along the remains of the endoplasmatic reticulum. In the succeeding stage, most of the cytoplasmatic structures and mitochondria have disappeared or have undergone profound transformations. Nuclei and cells elongate and chromatin begins to condense near the nuclear envelope. An acrosomal complex appears at the tip of the nucleus. The acrosomal filament is thick and runs the entire length of the nucleus. Plasmalemmal invaginations at the cell surface give rise to tubules filled with an electron-dense material. Sperm cell maturation is completed in the ventral portion of the germinal part, near the testicular lumen. As a final step in spermiogenesis, cytoplasm of the last spermatid undergoes a moderate condensation and the cariotheca disappears. Mature sperm cells were found in a matrix of ""simple"" and ""complex"" corpuscles, the latter consisting of flattened, spindle-shaped secreted bodies. Rather than in individual sperm aggregates, spermatozoa were contained in a single droplet inside the vas deferens, on a large secretion mass, structured as rows of platelets sunk in a fine grained matrix. Each mature sperm cell is covered by a thick secreted coat. In contrast to the genera Rhombognathus and other Actinotrichida, Copidognathus displays a set of features that must be regarded as apomorphic. The absence of usual mitochondria, the presence of electro-dense tubules and secretions similar to those present in Thalassarachna and Halacarellus, and the pattern of nuclear condensation are possibly shared apomorphies with these latter genera. (C) 2010 Elsevier GmbH. All rights reserved.

Evolutionary patterns in neotropical Helieae (Gentianaceae): evidence from morphology, chloroplast and nuclear DNA sequences

Parsimony-based phylogenetic analyses of the neotropical tribe Helieae (Gentianaceae) are presented, including 22 of the 23 genera and 60 species. This study is based on data from morphology, palynology, and seed micromorphology (127 structural characters), and DNA sequences (matK, trnL intron, ITS). Phylogenetic reconstructions based on ITS and morphology provided the greatest resolution, morphological data further helping to tentatively place several taxa for which DNA was not available (Celiantha, Lagenanthus, Rogersonanthus, Roraimaea, Senaea, Sipapoantha, Zonanthus). Celiantha, Prepusa and Senaea together appear as the sister clade to the rest of Helieae. The remainder of Helieae is largely divided into two large subclades, the Macrocarpaea subclade and the Symbolanthus subclade. The first subclade includes Macrocarpaea, sister to Chorisepalum, Tochia, and Zonanthus. Irlbachia and Neblinantha are placed as sisters to the Symbolanthus subclade, which includes Aripuana, Calolisianthus, Chelonanthus, Helia, Lagenanthus, Lehmanniella, Purdieanthus, Rogersonanthus, Roraimaea, Sipapoantha, and symbolanthus. Generic-level polyphyly is detected in Chelonanthus and Irlbachia. Evolution of morphological characters is discussed, and new pollen and seed characters are evaluated for the first time in a combined morphological-molecular phylogenetic analysis.

Five vicarious genera from Gondwana: the Velloziaceae as shown by molecules and morphology

Background and Aims The amount of data collected previously for Velloziaceae neither clarified relationships within the family nor helped determine an appropriate classification, which has led to huge discordance among treatment by different authors. To achieve an acceptable phylogenetic result and understand the evolution and roles of characters in supporting groups, a total evidence analysis was developed which included approx. 20 % of the species and all recognized genera and sections of Velloziaceae, plus outgroups representatives of related families within Pandanales. Methods Analyses were undertaken with 48 species of Velloziaceae, representing all ten genera, with DNA sequences from the atpB-rbcL spacer, trnL-trnF spacer, trnL intron, trnH-psbA spacer, ITS ribosomal DNA spacers and morphology. Key Results Four groups consistently emerge from the analyses. Persistent leaves, two phloem strands, stem cortex divided in three regions and violet tepals support Acanthochlamys as sister to Velloziaceae s. s., which are supported mainly by leaves with marginal bundles, transfusion tracheids and inflorescence without axis. Within Velloziaceae s. s., an African Xerophyta + Talbotia clade is uniquely supported by basal loculicidal capsules; an American clade, Barbacenia s. l. + Barbaceniopsis + Nanuza + Vellozia, is supported by only homoplastic characters. Barbacenia s. l. (Aylthonia + Barbacenia + Burlemarxia + Pleurostima) is supported by a double sheath in leaf vascular bundles and a corona; Barbaceniopsis + Nanuza + Vellozia is not supported by an unambiguous character, but Barbaceniopsis is supported by five characters, including diclinous flowers, Nanuza + Vellozia is supported mainly by horizontal stigma lobes and stem inner cortex cells with secondary walls, and Vellozia alone is supported mainly by pollen in tetrads. Conclusions The results imply recognition of five genera (Acanthochlamys (Xerophyta (Barbacenia (Barbaceniopsis, Vellozia)))), solving the long-standing controversies among recent classifications of the family. They also suggest a Gondwanan origin for Velloziaceae, with a vicariant pattern of distribution.

On the Generic Identity of Siagonodon brasiliensis, with the Description of a New Leptotyphlopid from Central Brazil (Serpentes: Leptotyphlopidae)

The geographic variation and hemipenial morphology of Siagonodon brasiliensis are described based on a comprehensive sample, allowing the reappraisal of its generic identity, and the proposal of a new nomenclatural combination. We suggest that the presence of two supralabials, as mentioned in the original description of S. brasiliensis, is not a common feature for this species, occurring at low frequencies throughout its geographic distribution. Based on a diagnosis presented in a recently published paper, as well as on additional external traits and on hemipenial characters, we recognize Siagonodon brasiliensis as a species of the genus Tricheilostoma. In addition, a new species of worm snake of the genus Siagonodon is described from the savannas of the state of Tocantins, Brazil. The new species differs from other congeners by having a slightly acuminate snout in lateral and ventral views, subcircular rostral in dorsal view, and 12 scale rows around middle of tail. The diagnosis of the genus Siagonodon is revised and expanded based on direct observation of morphological characters.

A new species of Lauromacromia (Odonata: Corduliidae) from Southeastern Brazil, with a cladistic analysis of the genus and comments on Neotropical dragonfly biogeography

Lauromacromia melanica sp. nov. from Conceicao da Barra municipality, Espirito Santo State, Brazil, is described and illustrated based on two males (both in MNRJ n degrees 135). The new species is similar to L. picinguaba differing from it mainly by the absence of pale spots on S3-6 and by the ellipsoid shape of metepisternal pale stripe. A key for males of all species of the genus is provided. A cladistic analysis encompassing 43 external morphological male characters carried out in two distinct procedures, the first with all characters unordered and the second with two or three state characters ordered. The unordered analysis generated only one most-parsimonious tree (66 steps of length, CI = 0.69, RI = 0.62). The hypothesis of monophyly of Lauromacromia is supported and includes three groups, one formed by the Atlantic Forest species (L. melanica sp. nov. + L. picinguaba), and another by the Cerrado species (L. flaviae + (L. bedei + L. luismoojeni)), and L. dubitalis, positioned in polytomy with these two groups. The ordered analysis also generated only one most-parsimonious tree (68 steps of length, CI = 0.70, RI = 0.67), which maintained the monophyly of Lauromacromia but L. dubitalis positioned basally as sister-group to the Atlantic Forest + Cerrado species groups. The geographic distribution of Lauromacromia is updated with a new record of L. luismoojeni based on one adult male (Brazil: Mato Grosso do Sul State) and probable first Brazilian records for L. dubitalis (Amazonas and Para States) based on two larvae. A vicariance hypothesis is proposed to explain spatial evolution of Lauromacromia, and based on current biogeographical classifications we consider Gomphomacromia and Rialla apart from Neotropical biota. Some aspects of biology and ecology of Lauromacromia are also discussed.

Effects of exercise on the morphology of the myenteric neurons of the duodenum of Wistar rats during the ageing process

This study aimed to evaluate the effects of regular physical activity on the morphology of the myenteric plexus of the duodenum in rats during the ageing process. To this end, 45 Wistar rats were divided into three groups: C (sedentary - 6 months old), S (sedentary - 12 months old) and T (trained - 12 months old). The animals of group S were given with a physical activity programme consisting of a 10-min-treadmill workout once a week. The animals of group T were submitted to the physical activity programme five times a week. Their duodenums were collected and submitted to the techniques of nicotinamide adenine dinucleotide (NADH)-diaphorase enzyme histochemistry for whole-mount preparations and transmission electron microscopy. No differences in the constitution of the myenteric plexuses were found when the sedentary and trained groups were compared with the control group. The ultrastructural features were similar for the three groups. However, it was verified that the physical activity of the trained animals resulted in a similar myenteric neuron morphology to that of the adult animals (6 months old), thereby confirming its beneficial effect, as the sedentary animals had larger alterations in the collagen fibrils and the basal membrane that occur through ageing. The quantitative analysis showed that the NADH-diaphorase positive neurons decreased with ageing and increased with physical activity (P > 0.05). No significant alteration (P > 0.05) in the neuronal profile area of the NADH-diaphorase positive neurons has been observed with ageing.

Three-dimensional Reconstruction of Ovaries of Leaf-cutting Ant (Atta sexdens rubropilosa) Queens (Hymenoptera: Formicidae)

In this study, the ovary morphology of newly emerged ant queens of Atta sexdens rubropilosa was studied in whole mount preparations by confocal microscopy. The ovaries are composed of approximately 40 ovarioles, showing non-synchronic oocyte maturation. The terminal filament with clusters of undifferentiated cells was found at the distal end of the ovarioles. Next to this region is the germarium, composed of several elongated cystocytes interconnected by cytoplasmic bridges. The nurse cells (23-28 cells) result from asymmetric mitosis. Cytoskeleton analysis showed F-actin concentrated at the muscle cells of the external tunica and in fusomes inside the ovarioles. Microtubules were concentrated around the nuclei of the nurse and follicular cells. In contrast, the oocytes and the external tunica showed faint staining for tubulin.

Effect of a calcium-channel blocker (verapamil) on the morphology, cytoskeleton and collagenase activity of human skin fibroblasts

The effects of verapamil modulating collagen biosynthesis have prompted us to study the role of this drug in cultured fibroblasts. In this article, we describe the effects of verapamil on fibroblast behaviour, with special emphasis to phenotypic modifications, reorganisation of actin filaments and secretion of MMP1. Human dermal fibroblasts treated with 50-mu M verapamil changed their normal spindle-shaped morphology to stellate. Treated cells showed discrete reorganisation of actin filaments, as revealed by fluorescein isothiocyanate (FITC)-phalloidin staining and confocal microscopy. We hypothesised that these effects would be associated to lower levels of cytosolic Ca(2+). Indeed, short time loading with calcium green confirmed that verapamil-treated fibroblasts exhibited lower intracellular calcium levels compared to controls. We also observed that verapamil increases the secretion of MMP1 in cultured fibroblasts, as demonstrated by zymography, specific substrate assays and immunoblot. The morphological alterations induced by verapamil are neither cytotoxic nor associated with other dramatic cytoskeleton alterations. Thus we may conclude that this drug enhances collagenase secretion and does not disrupt the major tracks necessary to deliver these enzymes in the extracellular space. The present results suggested that verapamil could be used at physiological levels to enhance collagen I breakdown, and maybe considered a potential candidate for intralesional therapy of wound healing and fibrocontractive diseases. (C) 2010 Elsevier Ltd and ISBI. All rights reserved.

The Estrous Cycle Modulates Small Leucine-Rich Proteoglycans Expression in Mouse Uterine Tissues

In the pregnant mouse uterus, small leucine-rich proteoglycans (SLRPs) are drastically remodeled within a few hours after fertilization, suggesting that ovarian hormone levels modulate their synthesis and degradation. In this study, we followed by immunoperoxidase approach, the presence of four members of the SLRP family (decorin, lumican, biglycan, and fibromodulin) in the uterine tissues along the estrous cycle of the mouse. All molecules except fibromodulin, which predominates in the myometrium, showed a striking modulation in their distribution in the endometrial stroma, following the rise in the level of estrogen. Moreover, notable differences in the distribution of SLRPs were observed between superficial and deep stroma, as well as between the internal and external layers of the myometrium. Only biglycan and fibromodulin were expressed in the luminal and glandular epithelia. All four SLRPs were found in cytoplasmic granules of mononucleated cells. The pattern of distribution of the immunoreaction for these molecules in the uterine tissues was found to be estrous cycle-stage dependent, suggesting that these molecules undergo ovarian hormonal control and probably participate in the preparation of the uterus for decidualization and embryo implantation. In addition, this and previous results from our laboratory suggest the existence of two subpopulations of endometrial fibroblasts that may be related to the centrifugal development of the decidua. Anat Rec, 292:138-153, 2009. (c) 2008 Wiley-Liss, Inc.