Genomic analyses reveal two species of the matamata (Testudines: Chelidae: Chelus spp.) and clarify their phylogeography.

The matamata is one of the most charismatic turtles on earth, widely distributed in northern South America. Debates have occurred over whether or not there should be two subspecies or species recognized due to its geographic variation in morphology. Even though the matamata is universally known, its natural history, conservation status and biogeography are largely unexplored. In this study we examined the phylogeographic differentiation of the matamata based on three mitochondrial DNA fragments (2168 bp of the control region, cytochrome oxidase subunit I, and the cytochrome b gene), one nuclear genomic DNA fragment (1068 bp of the R35 intron) and 1661 Single Nucleotide Polymorphisms (SNPs). Our molecular and morphological analyses revealed the existence of two distinct, genetically deeply divergent evolutionary lineages of matamatas that separated in the late Miocene (approximately 12.7 million years ago), corresponding well to the time when the Orinoco Basin was established. As a result of our analyses, we describe the genetically and morphologically highly distinct matamata from the Orinoco and Río Negro Basins and the Essequibo drainage as a species new to science (Chelus orinocensis sp. nov.). Chelus fimbriata sensu stricto is distributed in the Amazon Basin and the Mahury drainage. Additionally, the analyses revealed that each species displays phylogeographic differentiation. For C. orinocensis, there is moderate mitochondrial differentiation between the Orinoco and the Río Negro. For C. fimbriata, there is more pronounced differentiation matching different river systems. One mitochondrial clade was identified from the Amazon, Ucayali, and Mahury Rivers, and another one from the Madeira and Jaci Paraná Rivers. The C. orinocensis in the Essequibo and Branco Rivers have haplotypes that constitute a third clade clustering with C. fimbriata. Phylogenetic analyses of the R35 intron and SNP data link the matamatas from the Essequibo and Branco with the new species, suggesting past gene flow and old mitochondrial introgression. Chelus orinocensis is collected for the pet trade in Colombia and Venezuela. However, neither the extent of the harvest nor its impact are known. Hence, it is crucial to gather more information and to assess its exploitation throughout its distribution range to obtain a better understanding of its conservation status and to design appropriate conservation and management procedures. RESUMEN: La matamata es una de las tortugas más carismáticas del mundo, ampliamente distribuida en el norte de Sudamérica. Debido a su variación morfológica geográfica, se debate sobre el reconocimiento de dos subespecies o especies. A pesar de que la matamata es universalmente conocida, su historia natural, estado de conservación y biogeografía han sido muy poco estudiados. En este estudio examinamos la diferenciación filogeográfica de las matamatas en base ​​a tres fragmentos de ADN mitocondrial (2168 pb de la región de control, la subunidad I del citocromo oxidasa y el gen del citocromo b), un fragmento de ADN genómico nuclear (1068 pb del intrón R35) y 1661 polimorfismos de nucleótido único (SNPs). Nuestros análisis moleculares y morfológicos revelaron la existencia de dos linajes evolutivos distintos de matamatas, genéticamente divergentes que se separaron en el Mioceno tardio (hace aproximadamente 12.7 millones de años), correspondiendo al tiempo en que se estableció la cuenca del Orinoco. Como resultado de nuestros análisis, describimos las genéticamente y morfológicamente distintas matamatas de las cuencas del Orinoco, Río Negro y Essequibo como una especie nueva para la ciencia (Chelus orinocensis sp. nov.). Chelus fimbriata sensu stricto se distribuye en la cuenca del Amazonas y en el drenaje del Mahury. Adicionalmente, los análisis revelaron que cada especie muestra diferenciación filogeográfica. Para C. orinocensis, hay una moderada diferenciación mitocondrial entre el Orinoco y el Río Negro. Para C. fimbriata, hay una diferenciación más pronunciada, concordando con los diferentes sistemas fluviales. Se identificó un clado de los ríos Amazonas, Ucayali y Mahury y otro de los ríos Madeira y Jaci Paraná. Las C. orinocensis de los ríos Essequibo y Branco tienen haplotipos que constituyen un tercer clado que se agrupa con C. fimbriata. Los análisis filogenéticos del intrón R35 y los datos de SNP asocian las matamatas de Essequibo y Branco con la nueva especie, sugiriendo flujo de genes pasado ​​e introgresión mitocondrial antigua. Chelus orinocensis se colecta para el comercio de mascotas en Colombia y Venezuela. Sin embargo, ni se conoce el alcance de las colectas ni su impacto. Por lo tanto, es crucial recopilar más información y evaluar su explotación en todo su rango de distribución, comprender mejor su estado de conservación y para diseñar acciones apropiadas de conservación y manejo.

Liolaemus jamesi (Boulenger, 1891): restriction of the type locality and holotype characterization (Squamata: Liolaemidae).

Liolaemus is one of the most diverse genus of lizards in the world (Esquerré et al. 2013), with 257 species listed in the last review focusing on its diversity (Abdala Quinteros 2014). Certain species within this genus, especially the earlier ones, were described in very little detail, even lacking an appropriate description of the holotype and/or type locality. This has created uncertainties in the taxonomic identity of several Liolaemus species (Espinoza et al. 2011; Quinteros et al. 2008; Troncoso-Palacios Garin 2013; Langstroth 2011).

The taxonomic status of the "forgotten" Bolivian snakes, Atractus balzani Boulenger 1898 and Atractus maculatus (sensu Boulenger 1896) (Serpentes: Dipsadidae).

The genus Atractus Wagler 1828 comprises almost 150 currently recognized species of cryptozoic snakes widespread in the Neotropics, occurring from Panama to northeastern Argentina (Passos et al. 2016a). Despite the publication of the descriptions of several new species within the last decade, the taxonomy of the genus is unclear in some instances. This is mainly due to the fact that a number of poorly delimited taxa still exist (Passos et al. 2018). The most frequent problem faced by taxonomist working with the genus Atractus is the lack of specimens available for several species, most of them only still being known from their types, a situation that considerably weakens the definition of species boundaries between closely related taxa (Passos et al. 2010a, 2013). More importantly, many of the previously recognized species may represent aberrant individuals with unusual or abnormal scale counts, anomalous azygous or fused cephalic plates, infrequent polychromatic patterns, or any combination of these states (see Passos et al. 2016b). In the course of a thorough taxonomic review of the genus (Passos 2008; Passos et al. 2018), an effort has been made to examine all of the available types (including those apparently lost or misplaced in collections) and material of historical importance that was previously referred to the genus in the literature, and these were then compared to newer samples collected more recently. During the examination of the collections of the Natural History Museum of London and the Museo Civico di Storia Naturale of Genova, we found important specimens of Atractus from Bolivia. However, in order to better understand all the problems related to these old and "forgotten" Bolivian snakes, we need to examine their history.

Modified Whittaker plots as an assessment and monitoring tool for vegetation in a lowland tropical rainforest.

Resource exploitation in lowland tropical forests is increasing and causing loss of biodiversity. Effective evaluation and management of the impacts of development on tropical forests requires appropriate assessment and monitoring tools. We propose the use of 0.1-ha multi-scale, modified Whittaker plots (MWPs) to assess and monitor vegetation in lowland tropical rainforests. We established MWPs at 4 sites to: (1) describe and compare composition and structure of the sites using MWPs, (2) compare these results to those of 1-ha permanent vegetation plots (BDPs), and (3) evaluate the ability of MWPs to detect changes in populations (statistical power). We recorded more than 400 species at each site. Species composition among the sites was distinctive, while mean abundance and basal area was similar. Comparisons between MWPs and BDPs show that they record similar species composition and abundance and that both perform equally well at detecting rare species. However, MWPs tend to record more species, and power analysis studies show that MWPs were more effective at detecting changes in the mean number of species of trees > or = 10 cm in diameter at breast height (dbh) and in herbaceous plants. Ten MWPs were sufficient to detect a change of 11% in the mean number of herb species, and they were able to detect a 14% change in the mean number of species of trees > or =10 cm dbh. The value of MWPs for assessment and monitoring is discussed, along with recommendations for improving the sampling design to increase power.

Barriers and Associated Factors Affecting the Uptake of Cataract Surgery Among the Adult Population Age Forty and Over in Trinidad and Tobago

Untreated cataract worsens over time which can result in severe vision impairment, leading to blindness thereby contributing to the limitations in the overall functioning of an individual. Cataract extraction can greatly improve one's vision and by extension quality of life (QoL). However, the uptake of cataract surgery is affected by barriers such as affordability, and poor accessibility and availability (AU)