José Ayarzagüena

Phylogenetic relationships of glassfrogs (Centrolenidae) based on mitochondrial and nuclear genes

Glassfrogs (family Centrolenidae) represent an exceptionally diverse group among Neotropical anurans, but their evolutionary relationships never have been assessed from a molecular perspective. Mitochondrial and nuclear markers were used to develop a novel hypothesis of centrolenid phylogeny. Ingroup sampling included 100 terminals, with 78 (53%) of the named species in the family, representing most of the phenotypic diversity described for the group. Thirty-five species representing taxa traditionally associated with glassfrogs were used as outgroups. Gene sampling consisted of complete or partial sequences of three mitochondrial (12S, 16S, ND1) and three nuclear markers (c-myc exon 2, RAG1, POMC) for a total of approximately 4362bp. Phylogenies were estimated using maximum parsimony, maximum likelihood, and Bayesian analyses for individual genes and combined datasets. The separate analysis of mitochondrial and nuclear datasets allowed us to clarify the relationships within glassfrogs; also, we corroborate the sister-group relationship between Allophryne ruthveni and glassfrogs. The new phylogeny differs significantly from all previous morphology-based hypotheses of relationships, and shows that hypotheses based on few traits are likely to misrepresent evolutionary history. Traits previously hypothesized as unambiguous synapomorphies are shown to be homoplastic, and all genera in the current taxonomy (Centrolene, Cochranella, Hyalinobatrachium, Nymphargus) are found to be poly- or paraphyletic. The new topology implies a South American origin of glassfrogs and reveals allopatric speciation as the most important speciation mechanism. The phylogeny profoundly affects the traditional interpretations of glassfrog taxonomy, character evolution, and biogeography-topics that now require more extensive evaluation in future studies.

Multiple Paternity in a Reintroduced Population of the Orinoco Crocodile (Crocodylus intermedius) at the El Frío Biological Station, Venezuela.

The success of a reintroduction program is determined by the ability of individuals to reproduce and thrive. Hence, an understanding of the mating system and breeding strategies of reintroduced species can be critical to the success, evaluation and effective management of reintroduction programs. As one of the most threatened crocodile species in the world, the Orinoco crocodile (Crocodylus intermedius) has been reduced to only a few wild populations in the Llanos of Venezuela and Colombia. One of these populations was founded by reintroduction at Caño Macanillal and La Ramera lagoon within the El Frío Biological Station, Venezuela. Twenty egg clutches of C. intermedius were collected at the El Frío Biological Station for incubation in the lab and release of juveniles after one year. Analyzing 17 polymorphic microsatellite loci from 335 hatchlings we found multiple paternity in C. intermedius, with half of the 20 clutches fathered by two or three males. Sixteen mothers and 14 fathers were inferred by reconstruction of multilocus parental genotypes. Our findings showed skewed paternal contributions to multiple-sired clutches in four of the clutches (40%), leading to an overall unequal contribution of offspring among fathers with six of the 14 inferred males fathering 90% of the total offspring, and three of those six males fathering more than 70% of the total offspring. Our results provide the first evidence of multiple paternity occurring in the Orinoco crocodile and confirm the success of reintroduction efforts of this critically endangered species in the El Frío Biological Station, Venezuela.

Resurrection of Hyalinobatrachium orocostale and Notes on the Hyalinobatrachium orientale Species Complex (Anura: Centrolenidae)

Abstract Hyalinobatrachium orientale has a complex taxonomic history suggesting that more than one species could be under this name. In this review, we try to clarify the current taxonomic status of this species by means of morphological, bioacoustic, and mitochondrial DNA sequence comparisons of specimens from Tobago Island and the Venezuelan Cordillera de la Costa (Oriental Sector, Cordillera del Litoral and Cordillera del Interior). Our data support the resurrection of Hyalinobatrachium orocostale, restricted to the Cordillera del Interior. Additionally, specimens from Cordillera del Litoral and Oriental Sector do not form a monophyletic group; hence, we define as Hyalinobatrachium sp. the populations from Cordillera del Litoral and H. orientale sensu stricto the populations from the Oriental Sector. Preliminary bioacoustic and morphological analyses indicate that the populations from Tobago are conspecific with Hyalinobatrachium orientale sensu stricto.

A NEW SPECIES OF HYPSIBOAS (AMPHIBIA; ANURA; HYLIDAE) FROM THE VENEZUELAN GUAYANA, WITH NOTES ON HYPSIBOAS SIBLESZI (RIVERO 1972)

We describe a new species of Hypsiboas from the slopes and summit of Auyán-tepui in Canaima National Park, Bolívar State, Venezuela. The new species resembles H. sibleszi, but it differs from that species in having pale green dorsal coloration with numerous small chromatophores, dorsolateral white stripes that extend from the tip of snout to the groin when present, pale interorbital bar absent, a transparent yellow venter, yellow-colored digits and webbing, a more extensive webbing on hands and feet, a prepollical spine not protunding, very narrow nasals partially fused with sphenethmoid, a moderate-sized frontoparietal fontanelle, and an advertisement call consisting of three or four notes with a dominant frequency between 3010 and 3488 Hz. New data on the vocalization, osteology and distribution of H. sibleszi are provided.

A new species of Hyla (Anura: Hylidae) from the highlands of venezuelan guayana

Abstract A new species of Hyla is described from Cerro Jaua, 1600 m, Bolívar State, Venezuela. The external appearance of the new species closely resembles Hyla benitezi and Hyla lemai but differs from these species in having cream-colored digits and webbing (in live specimens), a golden iris, less foot webbing, no quadratojugal, and a characteristic advertisement call that consists of a rhythmically repeated note with a dominant frequency between 3260 and 3450 Hz.

CONTRIBUTION TO THE KNOWLEDGE OF THE TAXONOMY, DISTRIBUTION, AND NATURAL HISTORY OF LEPOSOMA HEXALEPIS (REPTILIA: GYMNOPHTHALMIDAE) IN VENEZUELA

We provide a redescription of Leposoma hexalepis based on 32 specimens, including males for the first time, and detailed data on the external morphology of the species, meristic characters, pattern of coloration in life and after preservation, and its geographic distribution. Resumen Se redescribe a Leposoma hexalepis basados en una serie de 32 ejemplares, donde se incluye por primera vez a los machos de esta especie. Se ofrecen datos detallados sobre su morfología externa, caracteres merísticos, patrones de coloración en vida y en preservativo y su distribución geográfica.