Western Venezuela Research Articles

Registros más occidentales de Gonatodes albogularis fuscus (Squamata: Sphaerodactylidae) en Honduras y comentarios sobre su taxonomía y conservación

Gonatodes albogularis fuscus (Hallowell, 1855) is known mainly from the lowlands from Chiapas in Mexico to western Venezuela and Colombia and in several Caribbean islands. In Honduras it has been reported from the center, south, east and north, however there are no reports from the west of the country. We document this species for the first time in the departments of Comayagua and Intibucá in the center-west and comment on its distribution in Honduras. In addition, we suggest the need to reassess the taxonomy of subspecies of G. albogularis and comment about conservation problems derived from competition and predation by feral and invasive species and habitat modification.

New Galumnidae (Acari, Oribatida) from the Merida and Zulia States, Venezuela

Three new species of the family Galumnidae (Oribatida)—Sacculogalumna zuliaensis sp. nov., Pergalumna (Pergalumna) convergens sp. nov. and Carinogalumna meridaensis sp. nov.—are described, based on adults collected from cloud forest in the Merida State, Western Venezuela, and pasture meadow in the Zulia State, Northwestern Venezuela. The genera Sacculogalumna and Carinogalumna are registered in the Venezuelan fauna for the first time. Identification keys to the known species of Sacculogalumna and Carinogalumna are provided.

Typical computed tomography values in two institutions in the Western Venezuela

Typical computed tomography values in two institutions in the Western Venezuela

Ecogeographic rules in a common Neotropical treefrog: No clinal variation along a mountain range

AbstractBody and limb size are associated with many aspects of the biology of animals. Geographic variation in morphological traits has often been investigated through ecogeographical rules. Bergmann's rule posits an inverse relationship between body size and temperature in homeotherms, while Allen's rule posits that endothermic animals inhabiting colder climates have relatively shorter protruding parts (e.g., limbs) in comparison to populations from warmer climates. However, the applicability and validity of these rules in poikilotherms are currently contentious. In this study, we aimed to test predictions of Bergmann's and Allen's rules in populations of the Neotropical frog Boana platanera. We analysed 142 adult male museum specimens from 17 localities along a mountain range in western Venezuela. We obtained six external morphological measurements and assessed the correlation of body size and limb size with temperature data for each locality. Our results were contrary to the expectations but consistent with previous studies. All this together indicates that exceptions to the Bergmann's and Allen's rules are frequent and idiosyncratic in anurans. We discuss alternative hypotheses that could explain geographic variation of body and limb size in future studies.

Credit networks and business dynamics in a viceregal capital: Santafé de Bogotá in the age of Charles III

This article provides aggregate data on credit flows in Santafé de Bogotá, the capital of the Viceroyalty of New Granada (present-day Colombia, Ecuador and western Venezuela). By perusing a thorough report submitted to Bourbon authorities on notarial transactions, which included both ecclesiastical and non-ecclesiastical loans in the city, the article estimates the volume and size of lending activity while exploring how distinct types of credit interacted and shaped the business milieu of the region. It argues that by the late 1770s, Catholic Church lending had ceased to be the main source of investable funds in the region, with merchants and other non-ecclesiastical investors injecting growing funds into sectors traditionally avoided by ecclesiastical lenders such as commerce, mining and manufacturing. Network analysis suggests that merchants became brokers between different credit sources, alleviating information asymmetries and opening the credit market to borrowers with collateral and institutional restrictions willing to pay higher interest rates. Finally, by focusing on New Granada, the largest gold producer of the Spanish Empire, the article identifies some distinctive credit patterns that are different from those developed in silver-driven economies such as New Spain and Peru. Thus, the article provides new paths to study Latin American financial history.

President’s Column with Terry Palisch: Creating Our Energy Future (December 2023)

_ In this episode and transcript, Terry Palisch is joined by Simeon Eburi, an SPE Regional Director of North America, to discuss connecting members to technology and each other, and the importance of local sections. This transcript is an excerpt from the podcast episode. Listen to the full episode here. Simeon: I’m Simeon Eburi, an SPE Regional Director of North America and reservoir management advisor with Chevron. I’m pleased to join SPE President Terry Palisch to talk about the benefit of joining and being involved with your local SPE section. Thank you for inviting me to join you. As a regional director, I’m passionate about the sections and the work they do, as I know you are, Terry. Terry: Thank you, Simeon, for joining me today and being part of the episode. I asked you to join because I know your passion and your experience with the Gulf Coast Section, and my goal today is to ensure our members recognize how being active in their local section can help their professional development. I thought you would be the perfect host. I believe that when most people, both members and external, think about SPE they typically think about the local section. That is what most are exposed to, so I consider the local section the front lines of our Society, the key to SPE’s mission of connecting. I want to focus our members on how they can benefit by connecting with their local section or student chapter because I think the local sections can impact not only their education and career but also their energy future. Simeon: I agree with you Terry, sections are the front lines. I was very involved with my local section in Houston before I was a regional director on the SPE Board of Directors. For people who do not know about SPE sections, let’s start there. What are sections and what do they do? Terry: Let’s start with statistics. We have over 200 sections worldwide located in 85 countries, so wherever you are there should be a section near you. The first section was the Mid-Continent Section in Tulsa in 1917 over 100 years ago; it was established before SPE was incorporated. The first international section was about 40 years later, the Western Venezuela Section in Maracaibo. One of the most recent sections is the Ukraine Section in Kiev established in 2022. We continue to add sections and at times reinstate sections that may have fallen behind. This year we reinstated the Libya Section and the Tunisia Section. Our sections are wide-ranging in size. The two largest sections are the Kingdom of Saudi Arabia and the Gulf Coast Section with well over 8,000 members. What is interesting is that the average SPE section size is over 300 and the median is under 150 which means we have a lot of sections that are smaller than 150 members, which illustrates the idea of the sections being grassroots. Each section operates independently and somewhat autonomously; they are local in their local area. Each is unique in that they respond to the needs of their members, providing technical exchange, networking opportunities, and engaging with the community. They really are the face of SPE at the local level.

Is Eriocnemis luciani meridae (Aves: Trochilidae) a diagnosable taxon and does it come from Venezuela, with remarks on the collectors Salomn Briceo and Walther Frederick Henninger.

Eriocnemis luciani meridae was originally described from a single specimen collected in the late 19th century in western Venezuela. Subsequently a second specimen of E. luciani, also labelled Venezuela, has been taken as additional proof for a highly disjunct population of this hummingbird, which otherwise ranges from southwest Colombia to southern Peru (taxonomy-dependent). Eriocnemis l. meridae has been accepted by all of the global checklists of birds, but has been routinely ignored by Venezuelan sources. In an effort to resolve this dichotomy of treatment, we re-examined the specimens plumage in comparison with relevant material in two major European bird collections. We found that the characters used to erect E. l. meridae are only doubtfully or weakly expressed in the holotype and appear invisible in the Ohio specimen, but both are clearly referrable to the species E. luciani. Evidence that the second specimen was definitely collected in Venezuela is weak and its overall provenance is unclear. In contrast, an extensive historical investigation of the relevant collectors indicates that the holotype does appear to have been taken in Venezuela, although perhaps not in the precise locality indicated for it. This leaves an unusual situation whereby we consider the case for a separate Venezuelan endemic taxon to be unproven, but there is no incontrovertible reason to exclude the species from the countrys avifauna; according to recent niche modelling data it is best searched for in the Sierra Nevada of Mrida state. In contrast, a second subspecies of E. luciani, E. l. baptistae, described by the same authors as endemic to part of western Ecuador is, according to our reappraisal, clearly diagnosable and is upheld.

Phenotypic and genotypic study of antibiotic-resistant Escherichia coli isolates from a wastewater treatment plant in Zulia state, Venezuela.

Antibiotic-resistance in bacteria is a global health problem, and wastewater treatment plants can play a role in their dissemination. In this work, we used PCR and plasmid transformation to characterize antibiotic-resistance and the phylogenetic groups of Escherichia coli isolated from a treatment plant in Zulia, a state in western Venezuela. Thirty-six bacteria isolates were analyzed, of which 27 resulted resistant by disc diffusion primarily to tetracycline and sulfisoxazole but also to trimethoprim, chloramphenicol, ampicillin, and cip-rofloxacin. The tetA, sul2, floR, and blaTEM resistance genes were frequently present and, in most cases, transferable. dfrA12, tetB, sul3, sul1, and aadA2genes also were detected. The integrase gene intI1 was common in multidrug-resistant isolates. These results suggest that E. coli from the treatment plant is a reservoir of antibiotic-resistance genes, which signify a potential health threat. Additionally, the phylogroup C was predominant, which is unusual and may represent an adaptation of this group to environmental conditions or per-haps the most frequent phylogroup entering from the influent.

REE + Y signatures of the Navay phosphate deposit, SW Venezuela: Seawater paleoredox conditions and diagenetic implications

Phosphate rock occurrences in western Venezuela are well-known in Cretaceous sedimentary sequences, which are associated to the Caribbean-Tethyan passive margin, along an SW-trend belt of the Venezuelan Andes chain. In this study, the geochemical characteristics of the Navay phosphate deposit were investigated to discuss the ocean paleo-oceanographic conditions and diagenetic controls that prevailed during the deposit formation. The rare earth elements plus yttrium (REY) concentrations were determined and normalized with the Post-Archean Australian Shale (PAAS) values to generate the REY patterns. Our results reveal a typical seawater signature, except for the absence of a marked negative Ce* anomaly (Ce/Ce* = 0.76–1.00). The determined seawater REY patterns, along to the calculated ratios for (La/Sm)N = 0.78–1.00, and (La/Yb)N = 0.34–0.66, are similar to the modern oceanic water ratios. These data point to a lack of diagenetic alteration on the primary REY signatures, which corresponds with a terrigenous-free marine sediment source for the REY content present in the deposit. In brief: i) the slightly negative anomalies displayed by the Ce* and Eu*, accompanied by the Mn depletion, ii) a relative enrichment of some transition metal elements (V, Cr, and Cu), and iii) the low Mo/U ratios, are all of them considered as geochemical indicators of suboxic to anoxic conditions, which were predominated during the phosphogenetic processes of the deposit. Furthermore, our data reveals an economic potential of the phosphorites as a raw material to produce phosphoric acid (H3PO4) as well as a source of supply for rare earth elements, by means of: i) relative high grades of P2O5 (15.46–30.09 wt %), ii) low CaO/P2O5 ratios (1.22–1.28), iii) a lack of organic matter, chert or chalcedony, iv) a low content of Mg (0.07–0.22%), v) REE concentrations varying from 141.82 to 256.53 μg/g, with an average value of 208.14 μg/g; and vi) concentrations for toxic elements (i.e., V, Cr, Co, Ni, Cu, Zn, As, Sr, Pb, and U) below or at the acceptable levels, in comparison to commercial phosphorites worldwide.

Continental block motion in the Northern Andes from GPS measurements

SUMMARYNorthwestern South America is a plate boundary zone where the Nazca, Caribbean and South American plates interact to produce a wide area of active continental deformation from the Gulf of Guayaquil (latitude 3°S) to Venezuela. Previous studies have identified a ∼2000-km-long continental sliver, referred as the North Andean Sliver (NAS), squeezed between the Nazca, Caribbean and South American plates and escaping at ∼1 cm yr−1 northeastward with respect to South America. Subduction of the Nazca Plate beneath the NAS has produced a sequence of large and great earthquakes during the 20th century along the coast of Ecuador and Colombia. Large crustal earthquakes up to magnitude 7.7 have been documented along the proposed eastern boundary of the NAS. However, active tectonics data, historical and recent earthquakes all indicate active fault systems within the NAS, possibly resulting from the interaction of several tectonic blocks. Here, we derive an extensive horizontal velocity field using continuous and episodic GNSS data from 1994 to 2019.9, covering northern Peru, Ecuador, Colombia, Panama and Venezuela. We model the GNSS velocity field using a kinematic elastic block approach that simultaneously solves for rigid tectonic block rotations and interseismic coupling along the subduction interfaces and along major crustal faults. In contrast to previous results that considered a single rigid NAS, our dense GNSS velocity field demonstrates that the NAS undergoes significant internal deformation and cannot be modelled as single rigid block. We find that block kinematics in the northern Andes are well described by the rotation of 6 tectonic blocks, showing increasing eastward motion from south to north. The Eastern boundary of the sliver is defined by a right-lateral transpressive fault system accommodating 5.6–17 mm yr−1 of motion. Fragmentation of the NAS occurs through several fault systems with slip rates of 2–4 mm yr−1. Slow reverse motion is found across the sub-Andean domain in Ecuador and northern Peru at 2–4 mm yr−1, marking a transitional area between the NAS and stable South America. In contrast, such a transitional sub-Andean domain does not exist in Colombia and western Venezuela. At the northwestern corner of Colombia, fast (∼15 mm yr−1) eastward motion of the Panama block with respect to the NAS results in arc-continent collision. We propose that the Uramita fault and Eastern Panama Deformed Zone define the current Panama/NAS boundary, accommodating 6 and 15 mm yr−1 of relative motion, respectively. A fraction of the Panama motion appears to transfer northeastward throughout the San Jacinto fold belt and as far east as longitude ∼75°W. Along the Caribbean coast, our model confirms, slow active subduction at ∼4.5 mm yr−1 along the South Caribbean Deformed Belt offshore northern Colombia and a relatively uniform rate of ∼1–2 mm yr−1 offshore northern Venezuela. Along the Nazca/NAS subduction interface, interseismic coupling shows a first-order correlations between highly locked patches and large past earthquake ruptures. These patches are separated by narrow zones of low/partial coupling where aseismic transients are observed. Compared to previous studies, our interseismic coupling model highlights the presence of deep coupling down to 70 km in Ecuador.

The Mechanics of the Alcabalas: Reform, Local Bargaining, and Dwindling Taxation in New Granada, 1750–1810

AbstractThis article studies the mechanics of sales taxes in the viceroyalty of New Granada (present-day Colombia, Ecuador, Panama, and western Venezuela) during the second half of the eighteenth century. Advocating a careful examination of the accounting, institutional, and fiscal practices of North Andean customs houses, it provides an extensive discussion on how tax records can be harnessed to study the scope and nature of Bourbon reforms and to measure trade flows. The article pursues three interrelated goals. First, it studies the impact of local negotiations and jurisdictional fragmentation on local rates and revenue collection, providing new insights into the concrete mechanisms of tax bargaining. Second, the study reinterprets data on the main North Andean entrepôts of trade to measure fiscal cycles, real tax pressure, and tax incidence. Proposing a new method for examining customs records, this research shows how fiscal concessions and economic cycles led to diminishing fiscal revenues. Finally, the research places the viceroyalty within the broader context of fiscal change in the Spanish Empire, arguing that the region collected fewer revenues not only because of its comparatively smaller economic activity but also because the combination of custom and reform yielded lower taxation rates and unique fiscal structures.

Microhabitat, diet, and reproductive activity of a population of the Andean shrew Cryptotis tamensis (Eulipotyphla: Soricidae)

ABSTRACT The Tamá small-eared shrew is found in the Andean cloud forests of the Cordillera Oriental of Colombia and the Tamá paramo in western Venezuela. Few aspects of its biology are known, and all information comes from its original description. In a patch of oak cloud forest, we found a relatively abundant population of the species and studied its abundance, microhabitat preference, diet composition and reproductive features, and their relationship with the rainfall seasonality of the study area. The fieldwork was carried on for two years at altitudinal intervals from 2402 to 2627 m.a.s.l. We caught 44 shrews in microhabitats with dense vegetation cover, abundant litter and fallen trees; their abundance changed significantly through time, varying along with the precipitation of the month before the capture. We found seven groups of arthropods in their diet, the composition of which did not differ significantly between sexes, reproductive stages or seasons. These shrews have a specialised diet, with ants as the most important item. Reproductive males are distinguished externally by the presence of hypertrophic subcutaneous lateral glands. We found adult reproductive males and non-reproductive males throughout the duration of the study, and their abundance did not vary significantly with precipitation. In contrast, we did not capture females in the driest months of the years, and although adult non-reproductive females were also found, we found a significant relationship between the abundance of reproductive females and precipitation. Consequently, adult reproductive males would be a permanent reproductive resource for the females, which appear to adjust their reproductive activity during the rainy seasons.

Comorbilidad enfermedad de Chagas-COVID-19. ¿Ventaja para pacientes chagásicos?

Introduction. Chagas’s disease a neglected and debilitating tropical illness, caused by Trypanosoma cruzi-infection, afflicts millions of people in most Latin-American countries. In the same region, frequent and severe viral infection cases have been reported due to SARS-CoV-2, the causative agent of COVID-19, deemed as the worst global pandemic in the 21st century. Objective. To investigate the Chagas disease-COVID-19-relationship, and the comorbidity effect on chagasic patients living in communities where SARS-CoV-2 have circulated during the last two years causing severe cases and deaths. Material and methods. Randomly selected chagasic patients (N=50) from rural localities of western Venezuela, where COVID-19 has occurred, were evaluated in order to know whether they had suffered SARS-CoV-2- infection. COVID-infected chagasic patients were clinically compared with non-chagasic individuals (N=22) who had suffered the viruses in the same localities. Results. SARS-CoV-2-infection caused significantly less aggressive effects in chagasic patients than in non-chagasic patients, evidenced by the short-lasting scarce mild symptoms and the attenuated clinical profile (p<0.05), without further complications. Comparison revealed COVID-19 detection in 10% of chagasic patients, showing all of them mild clinical pattern and few symptoms, while non-chagasic COVID-infected control individuals, showed 45% and 13% severe and fatal cases, respectively. Conclusion. Chagasic patients suffering from COVID-19 comorbidity seem to express a robust immune response (Th1/Th2/Th17), which associated with anti-T. cruzi-glycoproteins circulating antibodies, directed to certain SARS-CoV-2glycoproteins (membrane/spike), may induce a short lasting and milder clinical profile. More investigations in populations where Chagas disease is endemic, is recommended.

On the occurrence of Scinax kennedyi (Pyburn, 1973) (Anura, Hylidae) in the state of Roraima, northern Brazil

Scinax comprises 129 species of treefrogs divided between the S. ruber and the S. catharinae clades. The S. rostratus group belongs to the S. ruber clade, and comprises ten species characterized by having a dark interorbital triangular mark, tubercle on the heel and by vocalizing in a head-down position. Within this group, S. kennedyi and S. rostratus are similar in that they are the only species that do not possess a row of tubercles on the lower jaw. In spite of their morphological similarity, they can be distinguished from each other by male size and advertisement call traits. Scinax kennedyi was described from eastern Colombia, and occurs from central Colombia to western Venezuela, whereas S. rostratus was described from northern Venezuela, and is thought to occur from Panama to eastern Venezuela, and in the Brazilian state of Pará. A recent study reported a population identified as S. rostratus from the state of Roraima, in northern Brazil. However, this population presented substantial differences in male size and advertisement call in comparison to the described for this species, and apparently it best fits the diagnosis of S. kennedyi instead. In view of this, the present study aimed to clarify the identity of this Brazilian population through a reassessment of its specimens and call recordings, together with the examination of data of S. kennedyi from its type locality, and of S. rostratus from northern Venezuela. Acoustic and morphological analyses revealed that specimens from northern Brazil were indeed misidentified as S. rostratus, and hence they were herein reassigned to S. kennedyi. The study therefore demonstrates the occurrence of S. kennedyi in Brazil, extending its distribution ca. 1,120 km east by south from its type locality, and ca. 844 km east-southeast from its easternmost previous record. With this reassessment, a clearer acoustic diagnosis between S. kennedyi and S. rostratus was provided, as well as further data on fine-scale temporal traits of their calls.

Three-dimensional magnetotelluric imaging of the Mérida Andes, Venezuela

The 100km wide Mérida Andes extend from the Colombian/Venezuelan border to the Coastal Cordillera. The mountain chain and its associated major strike-slip fault systems in western Venezuela formed due to oblique convergence of the Caribbean with the South American Plates and the north-eastwards expulsion of the North Andean Block. Due to the limited knowledge of lithospheric structures related to the formation of the Mérida Andes research projects have been developed to illuminate this zone with deep geophysical data. In this study, we present three-dimensional inversion of broadband magnetotelluric data, collected along a 240km long profile crossing the Mérida Andes and the Maracaibo and Barinas–Apure foreland basins. The distribution of the stations limits resolution of the model to off-profile features. Combining 3D inversion of synthetic data sets derived from 3D modelling with 3D inversion of measured data, we could derive a 10 to 15km wide corridor with good lateral resolution to develop hypotheses about the origin of deep-reaching anomalies of high electrical conductivity. The Mérida Andes appear generally as electrically resistive structures, separated by anomalies associated with the most important fault systems of the region, the Boconó and Valera faults. Sensitivity tests suggest that the Valera Fault reaches to depths of up to 12km and the Boconó Fault to more than 35km depth. Both structures are connected to a sizeable conductor located east of the profile at 12–15km depth. We propose that the high conductivity associated with this off-profile conductor may be related to the detachment of the Trujillo Block. We also identified a conductive zone that correlates spatially with the location of a gravity low, possibly representing a SE tilt of the Maracaibo Triangular Block under the mountain chain to great depths (>30km). The relevance of these tectonic blocks in our models at crustal depths seems to be consistent with proposed theories that describe the geodynamics of western Venezuela as dominated by floating blocks or orogens. Our results stress the importance of the Trujillo Block for the current tectonic evolution of western Venezuela and confirm the relevance of the Boconó Fault carrying deformation to the lower crust and upper mantle. The Barinas–Apure and the Maracaibo sedimentary basins are imaged as electrically conductive with depths of 4 to 5km and 5 to 10km, respectively. The Barinas–Apure basin is imaged as a simple 1D structure, in contrast to the Maracaibo Basin, where a series of conductive and resistive bodies could be related to active deformation causing the juxtaposition of older geological formations and younger basin sediments.

Uncovering species boundaries through qualitative and quantitative morphology in the genus Dasyprocta (Rodentia, Caviomorpha), with emphasis in D. punctata and D. variegata

Abstract The genus Dasyprocta Illiger, 1811 includes at least 13 species of medium-sized caviomorph rodents, widely distributed from Mexico to northern Argentina. Despite being abundant, largely diurnal, and easily identifiable by their external traits, the taxonomy of this genus remains poorly understood. In this work, we reviewed the taxonomy of Dasyprocta along the Andes and adjoining lowland areas of the western Neotropics, including samples from Mexico to northern Argentina, with emphasis on two species largely confounded—sometimes considered as synonyms—during the last century: D. punctata Gray, 1842 and D. variegata Tschudi, 1845. In the construction of our taxonomic hypotheses, we use a purely morphological approach, emphasizing qualitative and quantitative cranial features and external traits (color patterns). The results of multivariate statistical analysis and differences in color patterns support the species-level validity of D. punctata and D. variegata. Within this latter nominal form, we also include those populations from northern Argentina and eastern Bolivia that recently were referred to D. azarae. Based on our results, D. punctata (including bellula, callida, candelensis, chiapensis, chocoensis, colombiana, dariensis, isthmica, nuchalis, richmondi, underwoodi, yucatanica, and zuliae) extends from southern Mexico to Colombia, Ecuador, northernmost Peru, and western Venezuela, while D. variegata (including azarae, boliviae, and yungarum) is distributed from south–central Peru and southwestern Brazil to Bolivia and northwestern Argentina.

Rubiacearum Americanarum Magna Hama Pars XLVIII: A New View of Palicourea sect. Axillares and Description of Some New Species (Palicoureeae)

Many of the species classified in Psychotria L. subg. Heteropsychotria Steyerm. (Rubiaceae), including the species of Psychotria ser. Axillares (Hook. f.) Steyerm., have been shown to belong to Palicourea Aubl. based on morphological and molecular characters. This section is now treated as Palicourea sect. Axillares (Hook. f.) Borhidi, and includes 14 species found from southern Central America through the Andes of northwestern and western South America with a center of diversity in eastern Colombia and western Venezuela. This section is characterized by the combination of laminar, well-developed, bilobed stipules and mostly capitate, pseudoaxillary or sometimes terminal, mostly sessile inflorescences with numerous well-developed bracts that enclose the flowers but without enlarged involucral bracts. It is circumscribed differently here than it is by Borhidi. The nomenclatural summary, key, and diagnostic discussions that separate the species included here are based on several new taxonomic circumscriptions. No infraspecific taxa are recognized in Pal. axillaris (Sw.) Borhidi, but one of its varieties from Venezuela is raised to species status as Pal. villipila (Steyerm.) C. M. Taylor. The circumscription of Pal. rosacea (Steyerm.) Borhidi is expanded, and four species are newly described here: Pal. aristata C. M. Taylor from the Andes of southern Ecuador, Pal. quibdoana C. M. Taylor from northwestern Colombia, Pal. santanderiana C. M. Taylor from the Andes of eastern Colombia, and Pal. winfriedii C. M. Taylor from northern Venezuela.

Ethno-ornithological notes and neglected references on the Harpy Eagle Harpia harpyja in western Venezuela

Harpy Eagle Harpia harpyja has been documented only recently (2004) in the Lake Maracaibo basin of western Venezuela, specifically in the central Sierra de Perijá, at 1,100 m. Observations in the southern plains of the basin are reported from heretofore neglected sources published in 1599, 1889 and 1893. Two overlooked photographs of dead birds dating from 1947–51 (Perijá Mountains) and 1959 (Santa Bárbara del Zulia) are reproduced. Several other records are established (in 1974, the 1980s, 1994/95, 2002 and 2006), based on empirical observations and material evidence collected by anthropologists who have visited the still heavily forested area inhabited by the Barí people since the early 1960s. Circumstantial evidence of the use of Harpy Eagle bones and feathers by the indigenous Barí provides additional ethno-ornithological information. Although Harpy Eagle is currently categorised as Vulnerable in Venezuela, the cumulative historical evidence coupled with Species Distribution Modelling analysis predictions of suitable habitat locally available to the species suggests it might still be frequent in the western and southern Lake Maracaibo basin, where considerable expanses of tropical forest are conserved within four major protected areas and an indigenous reserve.

Moho depth map of northern Venezuela based on wide-angle seismic studies

As part of the lithosphere, the crust represents Earth's rigid outer layer. Some of the tools to study the crust and its thickness are wide-angle seismic studies. To date, a series of seismic studies have been carried out in Venezuela to determine in detail the crustal thickness in the southern Caribbean, in the region of the Caribbean Mountain System in northern Venezuela, as well as along the Mérida Andes and surrounding regions. In this study, a review of the wide-angle seismic data is given, incorporating new data from the GIAME project for western Venezuela, resulting in a map of Moho depth north of the Orinoco River, which serves as the basis for future integrated models. Differences in Moho depths from seismic data and receiver function analysis are discussed. From the Caribbean plate, Moho depth increases from 20 to 25 km in the Venezuela Basin to about 35 km along the coast (except for the Falcón area where a thinning to less than 30 km is observed) and 40–45 km in Barinas - Apure and Guárico Basins, and Guayana Shield, respectively. Values of more than 50 km are observed in the Maturín Basin and in the southern part of the Mérida Andes.

First ESR dating of quaternary sediments in Mérida Andes, Western Venezuela

The main objective of this study is to demonstrate that Electron Spin Resonance (ESR) dating of Quaternary sediments can be performed at Venezuelan Laboratory (Laboratorio de Física de la Materia Condensada – Instituto Venezolano de Investigaciones Científicas). The dating was carried out using quartz samples extracted from sedimentary Quaternary fill of three alluvial terraces (Qt12, Qt9 and Qt7) located along the Santo Domingo River (Mérida Andes, Western Venezuela), that have been previously studied and dated by Terrestrial Cosmogenic Isotope (10Be). The sedimentological characteristics of the Qt9 terrace fill indicate that the transport and sedimentation process of the sediments was under stable and high energy conditions. Our ESR dating suggest a maximum age of 85 ± 16 ka for this terrace, which is consistent with the 10Be ages previously published. In the case of the Qt12 and Qt7 terraces, field observations suggest a sediment transport process by debris flows, with rapid deposition. In this case, our ESR ages (228 ± 93 ka, 108 ± 33 ka, for Qt12 and Qt7, respectively) seem to be overestimated compared with the 10Be ages reported in previous studies. These results confirm that the sedimentary material to be used for dating through this technique must be deposited under stable conditions involving long-term sediment transport processes. This will allow the “optical bleaching” of paramagnetic centers to occur before the material is buried, as seems to have happened with the Qt9 terrace sample. The results discussed in this work support the existence of the technological and human resources necessary to carry out numerical dating of Quaternary sediments in Venezuela.