On the osteology of a distinctive specie of the genus Leptodactylus: Leptodactylus laticeps (Boulenger, 1917) (Anura, Leptodactylidae)

The osteology of Leptodactylus laticeps is described. This species is the most distinctive member of the pentadactylus species group, and possibly of the genus Leptodactylus, based on external morphology, skin secretions and some aspects of its life history. This paper notes some characters that differ from or were previously overlooked in, description of the Leptodactylus. These are: 1)arrangement cotylar type II, 2) sacral diapophyses expanded, 3) nasals contiguos or in contact with frontoprietals, and 4) an anterior ramus parasphenoid which can or cannot reach the palatines. Some characters could be useful for species diagnoses and/or phylogenetic studies, such as elongation of the pars facialis of maxilla, maxillary teeth found almost reaching quadratojugal or extending beyond quadratojugal, nasals with posterolateral projections very prominent, nasals almost or in contact with each other; high number of vomerine teeth, tip of palatines not acute, and an alary process of premaxilla which is oriented slightly postero-dorsally.Fil: Ponssa, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentin

Patterns of skull development in anurans: Size and shape relationship during postmetamorphic cranial ontogeny in five species of the Leptodactylus fuscus Group (Anura: Leptodactylidae)

The effect of allometric ontogenetic changes on morphology has been examined primarily in larval stages of anurans. To our knowledge, such studies after metamorphosis are non-existent, and this information is important because the skull acquires its adult configuration in that period. Using geometric morphometrics, we studied postmetamorphic shape changes in the skull of five species of the Leptodactylus fuscus Group (Leptodactylus bufonius, Leptodactylus elenae, Leptodactylus fuscus, Leptodactylus latinasus, and Leptodactylus mystaceus), a group of smallto medium-sized frogs. Size change is an important factor in explaining shape change during postmetamorphic growth in four of these species; ontogenetic trajectories have in general parallel directions and similar rates of shape change. L. latinasus skulls tend to differ in size and shape from the others, and the allometric model, although significant, explains low percentages of shape change. The diverging slope of its ontogenetic trajectory indicates nonheterochronic, allometric repatterning change regarding the ontogenies of L. bufonius, L. elenae, and L. fuscus. Conversely, ontogenetic scaling appears as the main mechanism modeling shape change as regard to L. mystaceus; hence, we suggest that a process of progenesis determines the small, juvenile-like cranium of L. latinasus. The disparity analysis shows a broader morphological divergence in metamorph morphospace than in adults, suggesting that postmetamorphic stages can contribute with informative characters to phylogenetic analysis. Differences in shapes between metamorphs and adults indicate that many changes occur after metamorphosis, but whether these changes result from internal or ecological requirements at different stages remains unknown.Fil: Ponssa, María Laura. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vera Candioti, María Florencia. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Spatial and temporal utilization in an assemblage of anurans from Kent’s Marsh, Gamboa, Panamá

La utilización espacial y temporal del hábitat en anuros está relacionada, entre otras, con las funciones de reproducción y desarrollo de manera que su determinación es indispensable para la comprensión de los factores que condicionan la supervivencia de las especies de una comunidad. Este estudio examina los patrones de distribución espacial y temporal como posibles factores que favorecen la coexistencia de diferentes especies de anuros en un mismo ambiente neotropical. El estudio se llevó a cabo de junio a septiembre de 1998, durante la estación lluviosa, en una charca temporal en Kent’s Marsh (Gamboa, Panamá). Durante el período de estudio se detectaron 14 especies de anuros, de las que 12 se encontraron cantando. La diversidad y abundancia de anuros fue mayor en la zona central, que fue la más heterogénea en cuanto a la vegetación. En el patrón general no se destaca un uso temporal diferencial, mostrándose más bien una superposición en la fenología de la mayoría de las especies durante la época lluviosa. El uso diferencial de los hábitats aparece como un posible mecanismo de segregación entre las especies.Fil: Ponssa, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentin

Osteology, natural history notes, and phylogenetic relationships of the poorly known Caribbean frog Leptodactylus nesiotus (Anura, Leptodactylidae)

The Leptodactylus melanonotus group consists of 15 species, but references to skeletal characters are available for only three species: L. leptodactyloides, L. melanonotus, and L. diedrus. Leptodactylus nesiotus is a member of the melanonotus group known only from the type locality, Bonasse swamp, on the Southwestern peninsula of Trinidad, Trinidad and Tobago. This species has been categorized as vulnerable given its restricted distribution. Herein, we report the adult osteology of L. nesiotus, the skeletal characters are compared with the available data from other Leptodactylusspecies. A phylogenetic analysis recovers a paraphyletic L. melanonotus group relative to the L. latrans group. A monophyletic “latrans-melanonotus” clade is supported by five synapomorphies. L. nesiotus is recovered as the sister species of L. validus, a relationship supported by two synapomorphies: T-shaped terminal phalanges and a dark-colored stripe on the outer surface of arm. In addition, we report on the ecology of this poorly known species.El grupo L. melanonotus del género Leptodactylus incluye 15 especies, aunque sólo existen reportes de caracteres osteológicos para tres de ellas: L. leptodactyloides, L. melanonotus y L. diedrus. Leptodactylus nesiotus es un miembro del grupo L. melanonotus que ha sido categorizado como vulnerable debido a su distribución restringida, ya que es conocido sólo de la localidad tipo: La ciénaga de Bonasse, sudoeste de la península de la isla Trinidad, Trinidad y Tobago. En este trabajo se aportan datos sobre la osteología de adultos de L. nesiotus, los cuales son comparados con lo observado en otras especies del género, y se sumaron a una matriz previamente elaborada. Esta fuente de caracteres se utilizó para realizar un análisis de parsimonia y proponer una hipótesis filogenética. El grupo L. melanonotus resultó parafilético respecto al grupo L. latrans. El clado latrans-melanonotus es apoyado por cinco sinapomorfías. Se infiere a Leptodactylus nesiotus como la especie hermana de L. validus, relación apoyada por dos sinapomorfías: falanges terminales en forma de T, y presencia de banda oscura en el borde externo del brazo. Además se reportan observaciones sobre la ecología de esta especie pobremente conocida.Fil: Ponssa, María Laura. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: de Sa, Rafael O.. University of Richmond; Estados UnidosFil: Jowers, Michael J.. University of Glasgow; Reino Unid

Phalanx morphology in salamanders: A reflection of microhabitat use, life cycle or evolutionary constraints?

Morphological patterns are modeled by the interaction of functional, phylogenetic, ecological, and/or developmental constraints. In addition, the evolution of life cycle complexity can favor phenotypic diversity; however, the correlation between stages of development may constrain the evolution of some organs. Salamanders present microhabitat and life cycle diversity, providing an excellent framework for testing how these factors constrain phenotypic evolution. We reconstructed the morphological evolution of the terminal phalanx using a sample of 60 extinct and living species of salamanders. Using a geometric morphometric approach combined with comparative analyses, we further investigated the impact of phylogenetic, ecological, and/or life cycle factors on the shape of the terminal phalanx. We find that the phylogeny has some influence in determining the dorsal shape of the phalanges; whereas a relationship between microhabitat or life cycle and the dorsal and lateral shapes of the phalanx was not observed in the analyzed species. The allometric pattern found in the phalanx shape implies that small phalanges are more curved and with more truncated end than bigger phalanges. The evolutionary rate of phalanx shape was higher in the semiaquatic species, and the morphological disparity was significantly higher on biphasic groups. These results contradict the hypothesis that a complex life cycle constrains body shape. Finally, the phalanx shape of the salamander remains quite conserved from the Mesozoic. This configuration would allow them to occur in the different microhabitats occupied by the salamander lineages.Fil: Ponssa, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Fratani Da Silva, Jéssica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Barrionuevo, J. Sebastián. Fundación Miguel Lillo; Argentin

Phylogenetic patterns and correlation of key structures for jumping: Bone crests and cross-sectional areas of muscles in Leptodactylus (Anura, Leptodactylidae)

Anurans are characterized by their saltatory mode of locomotion, which is associated with a specific morphology. The coordinated action of the muscles and bones of the pelvic girdle is key to the transmission of the force of the hindlimbs to the axial skeleton during jumping. Two features are critical for optimal locomotory performance: the cross-sectional area of muscle and the bone crest attachment sites. The first character is a proxy of the force exerted by the muscle, whereas the crests are muscle attachments sites related to muscle force. The provisory relationship between these features has previously been identified and bone crest size can be used to infer the magnitude and, therefore, muscle force in fossils records. In this work, we explore the correlation between the cross-sectional area of essential muscles to the jumping mechanism (longissimus dorsi, extensor iliotibialis B, tenuissimus, puboischiofemoralis internus B, coccygeo-sacralis and coccygeo-iliacus) and the bone crests where these muscles are inserted (dorsal tubercle, dorsal crest and urostylar crest) in species of the genus Leptodactylus. This genus, along with other leptodactylids, exhibits a diversity of locomotor modes, including jumping, hopping, swimming and burrowing. We therefore analyzed the morphometric variation in the two features, cross-sectional area and bone crest area, expecting a correlation with different locomotor types. Our results showed: (i) a correlation between the urostylar crest and the cross-sectional area of the related muscles; (ii) that the bone crest surface area of urostyle and ilium and the cross-sectional area of the corresponding muscles can be utilized to infer locomotor faculties in leptodactylid frogs; and (iii) that the evolution of both characters demonstrates a general tendency from lower values in leptodactylid ancestors to higher values in the Leptodactylus genus. The results attest to the importance of the comparison of current ecological and phylogenetic analogues as they allow us to infer functionality and behavior in fossil and extant groups based on skeletal evidence. Phylogenetic patterns in character evolution and their correlation with locomotory types could imply that functional restrictions are also inherited in leptodactylid.Fil: Ponssa, María Laura. Unidad Ejecutora Lillo Uel Conicet-fml San Miguel de Tucumán; ArgentinaFil: Fratani Da Silva, Jéssica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Abdala, Virginia Sara Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentin

Fibrillar organization in tendons: a pattern revealed by percolation characteristics of the respective geometric network

Since the tendon is composed by collagen fibrils of various sizes connected between them through molecular cross-links, it sounds logical to model it via a heterogeneous network of fibrils. Using cross sectional images, that network is operatively inferred from the respective Gabriel graph of the fibril mass centers. We focus on network percolation characteristics under an ordered activation of fibrils (progressive recruitment going from the smallest to the largest fibril). Analyses of percolation were carried out on a repository of images of digital flexor tendons obtained from samples of lizards and frogs. Observed percolation thresholds were compared against values derived from hypothetical scenarios of random activation of nodes. Strikingly, we found a significant delay for the occurrence of percolation in actual data. We interpret this finding as the consequence of some non-random packing of fibrillar units into a size-constrained geometric pattern. We erect an ideal geometric model of balanced interspersion of polymorphic units that accounts for the delayed percolating instance. We also address the circumstance of being percolation curves mirrored by the empirical curves of stress-strain obtained from the same studied tendons. By virtue of this isomorphism, we hypothesize that the inflection points of both curves are different quantitative manifestations of a common transitional process during mechanical load transference.Fil: Dos Santos, Daniel Andrés. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Instituto de Biodiversidad Neotropical; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Ponssa, María Laura. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tulli, María José. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Abdala, Virginia Sara Luz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Instituto de Biodiversidad Neotropical; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Herpetología; Argentin

The influence of locomotion and habitat use on tendo-muscular units of an anuran clade (Anura, Diphyabatrachia)

Tendons have unique mechanical properties, contributing to the transmission, amplification, and recycling of muscle energy. In this light, anuran tendons are especially interesting due to their highly mechanically demanding locomotor modes. Herein we aim to investigate the relation between tendons and muscles from two perspectives: (1) the tendinous area in relation to the potential force produced by associated muscles, and how this relation varies for different tendons of the anuran body; (2) the tendinous proportion of a tendo-muscle unit in relation to different locomotor modes and habitat uses in a monophyletic unranked anuran clade (Diphyabatrachia) which includes Leptodactylidae and Centrolenidae, two highly diverse frog family groups of the Neotropics. Our data suggest a significant and positive relation between tendon dimensions and potential muscle force for most of the analyzed elements. We also found that species of different locomotion and habitat use show a divergence of tendinous proportions for tendo-muscle units of the pectoral girdle and hindlimb. Notably, jumper-arboreal species differentiate from all others in all tendo-muscle units tested. Finally, the optimization of tendinous proportions showed great phylogenetic correspondence. These results are in agreement with the hypothesis that morphological variation is related to a combination of phylogenetic, functional, and ecological factors.Fil: Fratani Da Silva, Jéssica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Ponssa, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Rada, Marco. Museu de Zoologia Da Usp; BrasilFil: Abdala, Virginia Sara Luz. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentin

Historical Biogeography of the Leptodactylus fuscus Group (Anura, Leptodactylidae): Identification of Ancestral Areas and Events that Modeled their Distribution

The objective of the present study was to reconstruct the biogeographic history of the monophyletic group Leptodactylus fuscus. We carried out two complementary historical biogeographic approaches: one estimates the ancestral areas with the statistical dispersion and vicariance method (S-DIVA). The other detects disjoint distributions among sister groups, which provides information about barriers that separate populations through a spatial analysis of vicariance (VIP method). For that, we used a database of species presence records and a topology of a phylogenetic cladogram, both obtained from updated published data that incorporates the current phylogenetic, taxonomic and distributional arrangements for the group. For the analysis of ancestral areas, the following areas of the L. fuscus group distribution were used: the Carribean, Chacoan, Parana, Amazonian and North American in Pacific subregions. The optimal reconstruction obtained with S-DIVA showed five vicariance events, two extinctions and 50 dispersals. The spatial analysis of vicariance revealed 19 disjointed sibling nodes and two distributions on nodes removed in the consensus tree. The results suggest that the ancestor of the Leptodactylus fuscus group occupied large areas within the Amazon and Chacoan subregions. Due to several dispersal events, the ancestor distribution range may have expanded to the Caribbean subregion. This expansion could have occurred during wetter periods, when forests were more extensive, which would have allowed the invasion of open habitats within humid forest systems. It is important to note that ecological factors and marine transgressions that occurred during the Miocene could have had a great influence on the current distribution of the group.Fil: Caffaro, Matias Exequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Medina, Regina Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina. Pontificia Universidad Católica de Chile; ChileFil: Ponssa, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Diaz Gomez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentin

Testicular histology of Anurans that deposit eggs out of the water

Anuran amphibians show the largest diversity of amphibian reproductive modes,many of which imply egg deposition out of the water. This kind of egg depositionrequires specialisations to avoid egg desiccation. Physiological, anatomical and ethological traits integrate to define these modes. In particular, morphological featuresof the urogenital system correlate with these reproductive modes and the environmental conditions where egg-laying occurs. In this study, we describe the testicularhistology and spermatogenesis of the nest-building frog Leptodactylus latinasus, andwe compare it with other species that breed out of water. We found variations in testis size, the thickness of interstitial tissue, tunica albuginea, and peritubular tunics,flagellum length, and in the shape and size of the spermatozoal nucleus. Certainspecifics? characters differed at the species level, but not between families. Suchvariation could be an indicator of spermatozoal performance and environmentalconstraints under which fertilisation takes place.Fil: Pucci Alcaide, Ana. Instituto de Morfología Animalfundación Miguel Lillotucumán; ArgentinaFil: Pucci Alcaide, Franco Jose. Instituto de Morfología Animalfundación Miguel Lillotucumán; ArgentinaFil: Michel, Adriana Azucena. Instituto de Morfología Animalfundación Miguel Lillotucumán; ArgentinaFil: Ponssa, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentin