Diversification dynamics of a common deep-sea octocoral family linked to the Paleocene-Eocene thermal maximum.

The deep-sea has experienced dramatic changes in physical and chemical variables in the geological past. However, little is known about how deep-sea species richness responded to such changes over time and space. Here, we studied the diversification dynamics of one of the most diverse octocorallian families inhabiting deep sea benthonic environments worldwide and sustaining highly diverse ecosystems, Primnoidae. A newly dated species-level phylogeny was constructed to infer their ancestral geographic locations and dispersal rates initially. Then, we tested whether their global and regional (the Southern Ocean) diversification dynamics were mediated by dispersal rate and abiotic factors as changes in ocean geochemistry. Finally, we tested whether primnoids showed changes in speciation and extinction at discrete time points. Our results suggested primnoids likely originated in the southwestern Pacific Ocean during the Lower Cretaceous âˆ¼112 Ma, with further dispersal after the physical separation of continental landmasses along the late Mesozoic and Cenozoic. Only the speciation rate of the Southern Ocean primnoids showed a significant correlation to ocean chemistry. Moreover, the Paleocene-Eocene thermal maximum marked a significant increase in the diversification of primnoids at global and regional scales. Our results provide new perspectives on the macroevolutionary and biogeographic patterns of an ecologically important benthic organism typically found in deep-sea environments.

Review of the fossil matamata turtles: earliest well-dated record and hypotheses on the origin of their present geographical distribution.

The matamata (Chelus fimbriatus) is a highly aquatic chelid turtle known exclusively from northern South America. Due to its extremely modified morphology, it is well circumscribed among living taxa, but that is not the case of the two extinct species ascribed to the taxon, Chelus colombianus and Chelus lewisi. These were originally described for the Miocene of Colombia and Venezuela, respectively, and are known mostly from post-cranial material. Few traits have been considered diagnostic for these fossil taxa, and their shared geographic and temporal distributions raise doubts about their distinctiveness. Here, we describe new turtle remains from the early Miocene Castillo Formation, at Cerro la Cruz, northwestern Venezuela, assigning them to C. colombianus. We also review the taxonomy and diagnostic features of the fossil species of Chelus, comparing them with the variation recognized within C. fimbriatus. All alleged differences between the fossil Chelus species were found in our sample of the extant species, and may represent intraspecific variation of a single fossil species. Further, we reviewed the fossil record of Chelus spp. and proposed a paleobiogeographic hypothesis to explain its present geographic range.

A new Mourasuchus (Alligatoroidea, Caimaninae) from the late Miocene of Venezuela, the phylogeny of Caimaninae and considerations on the feeding habits of Mourasuchus.

Mourasuchus (Alligatoroidea, Caimaninae) is one of the most peculiar crocodyliforms due to the skull morphology consisting of a long, wide, dorsoventrally flat rostrum with long, slender mandibular rami. Despite these peculiarities, the systematics, phylogeny and feeding habits of this taxon have not been properly studied. In this paper, we describe a new species of the genus, Mourasuchus pattersoni sp. nov., from the late Miocene of the Urumaco Formation of Venezuela. The new species differs from the other Mourasuchus species in having a lateromedially wide, dorsoventrally high jugal bone and a circular incisive foramen, which both represent autapomorphies of the new taxon. Phylogenetically, M. pattersoni sp. nov. is more closely related to M. amazonensis and the specimen UFAC-1424 (formely attributed to M. nativus) than to M. arendsi or M. atopus, whilst Mourasuchus is recovered once more as a monophyletic group. Furthermore, the cladistic analysis performed in this contribution offers a new phylogenetic assessment of Caimaninae, including many taxa described recently for the group. In this study, we also discuss the crocodylian diversity of the Urumaco Formation as well as how paleoenvironment may have contributed toward its evolution. In addition, we provide a discussion of the potential feeding habits of Mourasuchus. In this contribution, Mourasuchus is regarded as a taxon that likely preferred to prey on small animals. The unusual skull morphology of this group may have evolved to cover a large area with the rostrum, allowing for a more efficient prey capture, while the prey may have consisted predominantly of large amounts of small animals.

The last marine pelomedusoids (Testudines: Pleurodira): a new species of Bairdemys and the paleoecology of Stereogenyina.

The extinct Stereogenyina turtles form a relatively diverse Podocnemididae lineage, with twelve described and phylogenetically positioned species. They are characterized by a wide geographic and temporal range, from the Eocene of Africa to the Pleistocene of Southeast Asia, and a peculiar palate morphology, with a secondary palate that is unique among side-necked turtles. Here, we describe a new Stereogenyina species, based on an almost complete skull from the middle Miocene Capadare Formation, of Venezuela. A new phylogenetic analysis supports the assignment of the new species to the genus Bairdemys. Based on geometric morphometrics analyses, we related the development of the stereogenyin secondary palate with the acquisition of a durophagous diet. Based on a review of the sedimentary environments where their fossils are found, we also propose that stereogenyins were a marine radiation of podocnemidid turtles, as corroborated by previous studies of fossil eggs and limb morphology. These two inferences allowed us to hypothesize that stereogenyins occupied an ecological niche similar to that of the extant Carettini sea turtles, and that the rise of the latter group may be related to the Stereogenyina diversity fall in the end of the Miocene.

A new enigmatic Late Miocene mylodontoid sloth from northern South America.

A new genus and species of sloth (Eionaletherium tanycnemius gen. et sp. nov.) recently collected from the Late Miocene Urumaco Formation, Venezuela (northern South America) is herein described based on a partial skeleton including associated femora and tibiae. In order to make a preliminary analysis of the phylogenetic affinities of this new sloth we performed a discriminate analysis based on several characters of the femur and tibia of selected Mylodontoidea and Megatherioidea sloths. The consensus tree produced indicates that the new sloth, E. tanycnemius, is a member of the Mylodontoidea. Surprisingly, the new taxon shows some enigmatic features among Neogene mylodontoid sloths, e.g. femur with a robust lesser trochanter that projects medially and the straight distinctly elongated tibia. The discovery of E. tanycnemius increases the diversity of sloths present in the Urumaco sequence to ten taxa. This taxon supports previous studies of the sloth assemblage from the Urumaco sequence as it further indicates that there are several sloth lineages present that are unknown from the better sampled areas of southern South America.

Erratum: A new enigmatic Late Miocene mylodontoid sloth from northern South America.

[This corrects the article DOI: 10.1098/rsos.140256.].

New dinosaur (Theropoda, stem-Averostra) from the earliest Jurassic of the La Quinta formation, Venezuelan Andes.

Dinosaur skeletal remains are almost unknown from northern South America. One of the few exceptions comes from a small outcrop in the northernmost extension of the Andes, along the western border of Venezuela, where strata of the La Quinta Formation have yielded the ornithischian Laquintasaura venezuelae and other dinosaur remains. Here, we report isolated bones (ischium and tibia) of a small new theropod, Tachiraptor admirabilis gen. et sp. nov., which differs from all previously known members of the group by an unique suite of features of its tibial articulations. Comparative/phylogenetic studies place the new form as the sister taxon to Averostra, a theropod group that is known primarily from the Middle Jurassic onwards. A new U-Pb zircon date (isotope dilution thermal-ionization mass spectrometry; ID-TIMS method) from the bone bed matrix suggests an earliest Jurassic maximum age for the La Quinta Formation. A dispersal-vicariance analysis suggests that such a stratigraphic gap is more likely to be filled by new records from north and central Pangaea than from southern areas. Indeed, our data show that the sampled summer-wet equatorial belt, which yielded the new taxon, played a pivotal role in theropod evolution across the Triassic-Jurassic boundary.

Erratum: Addendum to 'New dinosaur (Theropoda, stem-Averostra) from the earliest Jurassic of the La Quinta formation, Venezuelan Andes'.

[This corrects the article DOI: 10.1098/rsos.140184.].

Análisis de la calidad del capital humano de los optómetras lasallistas que laboran en la localidad de Chapinero / Analysis of quality of the human capital of La Salle optometrist working in the area of Chapinero

Se analizo la calidad del capital humano de 22 optómetras egresados de la universidad de La Salle que laboran en el sector óptico en la localidad de Chapinero en Bogotá, DC. Registrados ante la Camera de Comercio. Esto se realizó con base en una encuesta con doce preguntas de tipo cerrado las cuales se categorizaron de acuerdo con las variables que componen el concepto de capital humano- (Conocimientos, habilidades- destrezas y actitudes) En la variable conocimientos, se encontró que el 81 por ciento de los encuestados adelanto algún tipo de estudio luego de obtenido su grado profesional estos estudios fueron realizados en áreas clínicas de la optometría (45 por ciento), es importante anotar que predominan los estudios no formales. Las variables habilidades y destrezas muestran como principal fortaleza del optómetra, La refracción (31 por ciento) y la administración (31 por ciento) Y Lo anterior puede presentarse dada La naturaleza del trabajo que realizan estos profesionales en la localidad, La variable actitudes muestra que los profesionales de la localidad se sienten identificados con la filosofía de su empresa y además hacia el trabajo en equipo ya que un 41 por ciento de éstos participan en entidades de tipo asociativo o gremial. Observando éstas variables se puede concluir que los Optómetras Lasallistas que laboran en la localidad, prefieren la educación no formal para adquirir o actualizar sus conocimientos y que no han desarrollado en un grado superior habilidades y destrezas en otros campos como el cuidado primario, La terapia visual y los exámenes de apoyo diagnóstico. Las actitudes de los optómetras Lasallistas que laboran en esta localidad denotan su formación y su compromiso con el servicio.

Human capital of 22 optometrist graduated from La Universidad de La Salle working in the optical trade sector in the area of Chapinero and registered whit de Chamber of Commerce. This was done through survey with 12 closed-type questions which were categorized based on the variables that make up the concept of human capital. (Knowledge, Skills – Abilities and attitudes) in the knowledge area it was found that 81 percent of the people surveyed did some type of studies after graduating. These studies were related to the clinical area of optometry (45 percent). It is remarkable that non-formal studies predominate. The skill – ability variable shows as a principal strength of the optometrist, Refraction (31 percent) and Administration (31 percent). These results may be due to the nature of the work that these professionals perform in the area. The attitudes variable shows that they identify themselves with the philosophy of their companies and additionally, with teamwork as 41 percent participate in organizations of associative type. Looking into these variables it can be concluded that the la sallista Optometrist working in the area, prefer non formal education in order to acquire or update their knowledge and also that they have not developed, at a higher degree skills and abilities in other areas such as primary care, visual therapy and diagnosis support tests The attitudes of lasallistas optometrist working in the area reveal their integral education, and their commitment to service.