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Journal articles on the topic 'Guyana Shield'

Author: Grafiati

Published: 4 June 2021

Last updated: 2 February 2022

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1

Maslovsky, Alexey. "Gold deposits ot the Guiana shield." Ores and metals, no. 4 (February 2, 2021): 4–10. http://dx.doi.org/10.47765/0869-5997-2020-10023.

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The article provides a comparative analysis of Guyana and Venezuela major deposits within the Quartzstone ore field (Guyana). From the northwest to the southeast (from Venezuela to Brazil), more than 10 ore gold deposits are currently known, their total resources (including previous production) exceed 2,600 tons of gold (excluding the Amapari and Salamangoni deposits in Brazil). Almost all of Guyana deposits are confined to the Lower Proterozoic greenstone belts of the Guiana shield identified and explored for the past 15–20 years. The geological features of the largest deposits (Omay, Aurora, Toroparu, Tassawini and Monosi) are presented in the article.

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2

Girón, Jennifer C., and Andrew Edward Z. Short. "Three additional new genera of acidocerine water scavenger beetles from the Guiana and Brazilian Shield regions of South America (Coleoptera, Hydrophilidae, Acidocerinae)." ZooKeys 855 (June 13, 2019): 109–54. http://dx.doi.org/10.3897/zookeys.855.33013.

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Recent study of the water scavenger beetle subfamily Acidocerinae in the Neotropical region has uncovered numerous undescribed species that are not able to be placed in existing genera. Here, we describe three new genera to accommodate 17 of these new species from South America: Aulonocharesgen. nov. for Aulonochareslingulatussp. nov. (French Guiana, Suriname), Aulonocharesnovoairensissp. nov. (Brazil), and Aulonocharestubulussp. nov. (Brazil, Guyana, Suriname, Venezuela); Ephydrolithusgen. nov. for Ephydrolithushamadaesp. nov. (Brazil), Ephydrolithusminorsp. nov. (Brazil), Ephydrolithusogmossp. nov. (Brazil), Ephydrolithusspiculatussp. nov. (Brazil), and Ephydrolithustelisp. nov. (Brazil); and Primocerusgen. nov. for Primoceruscuspidissp. nov. (Venezuela), Primocerusgigassp. nov. (Venezuela), Primocerusneutrumsp. nov. (Guyana, Suriname, Venezuela), Primocerusocellatussp. nov. (Venezuela), Primoceruspetilussp. nov. (Brazil), Primoceruspijiguaensesp. nov. (Venezuela), Primocerusmaipuresp. nov. (Venezuela), Primocerussemipubescenssp. nov. (Guyana), and Primocerusstriatolatussp. nov. (Suriname). The genus Ephydrolithusgen. nov. is currently known to be restricted to seepages in the mountainous regions of the Brazilian Shield. Aulonocharesgen. nov. and Primocerusgen. nov. are both currently only known from the Guiana Shield, though widespread in that region where they are associated with streams and seeps. We present differential diagnoses, maps, habitat details, and illustrations of all new genera and species here described.

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3

ARMBRUSTER, JONATHAN W. "Peckoltia sabaji, a new species from the Guyana Shield (Siluriformes: Loricariidae)." Zootaxa 344, no. 1 (2003): 1. http://dx.doi.org/10.11646/zootaxa.344.1.1.

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Peckoltia sabaji is described based on specimens from the Guyana Shield regions of the Essequibo, Negro, and Orinoco River drainages of Guyana and Venezuela. Peckoltia sabaji is a member of the loricariid subfamily Hypostominae, tribe Ancistrini. The species differs from nearly all other members of the Hypostominae based on coloration — small spots on the head with spots becoming very large on the posterior part of the body. Those species with a similar coloration either do not have elongated bodies (vs. body very elongate) or have odontodes on the opercle as adults (vs. odontodes on opercle absent, rarely with one or two odontodes in adults).

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4

Forlani, Maurício C., Pedro H. Bernardo, and Hussam Zaher. "Amphibia, Anura, Hylidae, Phyllomedusa tarsius Cope, 1868: Distribution extension, new country record and geographic distribution map." Check List 8, no. 1 (2012): 155. http://dx.doi.org/10.15560/8.1.155.

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We provide a review of the geographic distribution of Phyllomedusa tarsius. A new record from Guyana corresponds to the eastern limit of the range for the species, which now includes the Guiana shield.

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MacCulloch, Ross D., and Robert P. Reynolds. "Amphibians and Reptiles from Paramakatoi and Kato, Guyana." Check List 8, no. 2 (2012): 207. http://dx.doi.org/10.15560/8.2.207.

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We report the herpetofauna of two neighboring upland locations in west-central Guyana. Twenty amphibian and 24 reptile species were collected. Only 40% of amphibians and 12.5% of reptiles were collected in both locations. This is one of the few collections made at upland (750–800 m) locations in the Guiana Shield.

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6

Pessoa, Edlley M., FÁBIO DE BARROS, and MARCCUS ALVES. "Orchidaceae from Viruá National Park, Roraima, Brazilian Amazon." Phytotaxa 192, no. 2 (2015): 61. http://dx.doi.org/10.11646/phytotaxa.192.2.1.

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Viruá National Park is located on the Guyana Shield, an area known for its high levels of biodiversity and endemism. Furthermore, the Brazilian portion of the Guyana Shield is very poorly known, so that floristic studies are needed to know the local distribution of the species. The aim of this study is to survey the species of Orchidaceae from Viruá National Park, Roraima State, Brazil. Orchidaceae are represented in the study area by 67 species and 45 genera. Epidendrum L. (9 spp.) and Catasetum Rich. ex Kunth (5 spp.) are the most diverse genera. These species comprise about 25% of the species and about 50% of the genera cited for the state of Roraima, northern Brazil, and include 19 new species records for the state. The dense forest (“terra-firme” and flooded forests) is more diverse (56 spp.) than the “campinarana” vegetation (13 spp.), and both share only a single species. Descriptions, illustrations, ecological comments, geographical distribution and an identification key are provided.

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7

Reis, Nelson Joaquim, Serge Nadeau, Leda Maria Fraga, et al. "Stratigraphy of the Roraima Supergroup along the Brazil-Guyana border in the Guiana shield, Northern Amazonian Craton - results of the Brazil-Guyana Geology and Geodiversity Mapping Project." Brazilian Journal of Geology 47, no. 1 (2017): 43–57. http://dx.doi.org/10.1590/2317-4889201720160139.

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ABSTRACT: The Geological and Geodiversity Mapping binational program along the Brazil-Guyana border zone allowed reviewing and integrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú-Ireng River between Mount Roraima (the triple-border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro-Burro Group of Guyana.

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8

Doerr, S. H. "Karst-like landforms and hydrology in quartzites of the Venezuelan Guyana shield: Pseudokarst or "real" karst?" Zeitschrift für Geomorphologie 43, no. 1 (1999): 1–17. http://dx.doi.org/10.1127/zfg/43/1999/1.

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9

Rosa, João Willy Corrêa, José Wilson Corrêa Rosa, and Reinhardt A. Fuck. "Geophysical structures and tectonic evolution of the southern Guyana shield, Brazil." Journal of South American Earth Sciences 52 (July 2014): 57–71. http://dx.doi.org/10.1016/j.jsames.2014.02.006.

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10

Fedón, Irene Carolina. "Liliopsida, Cyperaceae, Cephalocarpus confertus Gilly, Guyana Shield, Brazil, Colombia and Venezuela." Check List 7, no. 3 (2011): 348. http://dx.doi.org/10.15560/7.3.348.

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The genus Cephalocarpus (Cyperaceae), of South American distribution is represented by four species. The present work extends the distribution of Cephalocarpus cofertus Gilly based on analysis of samples from the Missouri Botanical Garden Herbarium, literature and online databases. As a result this species is reported for Brazil, Colombia and Venezuela and is removed from the endemic status for Venezuela.

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11

ABRAHÃO, VITOR, JAN MOL, and MARIO DE PINNA. "A new species of Cetopsis from the Guiana Shield (Siluriformes: Cetopsidae: Cetopsinae)." Zootaxa 4664, no. 2 (2019): 221–32. http://dx.doi.org/10.11646/zootaxa.4664.2.4.

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A new species of Cetopsis is described from Guiana Shield drainages in Guyana and Suriname. The new species is found in the Konawaruk River and tributaries, Essequibo River basin, Guyana, and in the Mauritie Creek, tributary to the Tempati River, upper Commewijne River basin, Suriname. The new taxon can be distinguished from all congeners by a combination of features: dark spots on sides of the body eye-sized or larger, dark, bilobed patch at the base of the caudal fin, absence of a dark humeral spot, absence of dark pigmentation along the fin-membrane posterior to the first dorsal-fin ray, dark pigmentation at the base of the dorsal fin, dark spots extending ventrally to the bases of anal-fin rays, and 41 total vertebrae with 28 caudal vertebrae. Data on internal anatomy of the new species were incorporated into a previously-published phylogenetic analysis and resolves the position of the new species as the sister group of C. motatanensis, from Lago Maracaibo basin. The new Cetopsis is the first species of the genus known to occur exclusively in the Guiana Shield.

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12

Pickles, Robert Stuart Alexander, Niall Patrick McCann, and Ashley Peregrine Holland. "Mammalian and avian diversity of the Rewa Head, Rupununi, Southern Guyana." Biota Neotropica 11, no. 3 (2011): 237–51. http://dx.doi.org/10.1590/s1676-06032011000300021.

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We report the results of a short expedition to the remote headwaters of the River Rewa, a tributary of the River Essequibo in the Rupununi, Southern Guyana. We used a combination of camera trapping, mist netting and spot count surveys to document the mammalian and avian diversity found in the region. We recorded a total of 33 mammal species including all 8 of Guyana's monkey species as well as threatened species such as lowland tapir (Tapirus terrestris), giant otter (Pteronura brasiliensis) and bush dog (Speothos venaticus). We recorded a minimum population size of 35 giant otters in five packs along the 95 km of river surveyed. In total we observed 193 bird species from 47 families. With the inclusion of Smithsonian Institution data from 2006, the bird species list for the Rewa Head rises to 250 from 54 families. These include 10 Guiana Shield endemics and two species recorded as rare throughout their ranges: the harpy eagle (Harpia harpyja) and crested eagle (Morphnus guianensis).

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13

Meyer, Henry O. A., and Malcolm E. McCallum. "Diamonds and their sources in the Venezuelan portion of the Guyana Shield." Economic Geology 88, no. 5 (1993): 989–98. http://dx.doi.org/10.2113/gsecongeo.88.5.989.

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14

Sobolev, N. V., E. S. Yefimova, D. M. DeR Channer, P. F. N. Anderson, and K. M. Barron. "Unusual upper mantle beneath Guaniamo, Guyana shield, Venezuela: Evidence from diamond inclusions." Geology 26, no. 11 (1998): 971. http://dx.doi.org/10.1130/0091-7613(1998)026<0971:uumbgg>2.3.co;2.

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15

Nomade, S., Y. Chen, G. Féraud, A. Pouclet, and H. Théveniaut. "First paleomagnetic and 40Ar/39Ar study of Paleoproterozoic rocks from the French Guyana (Camopi and Oyapok rivers), northeastern Guyana Shield." Precambrian Research 109, no. 3-4 (2001): 239–56. http://dx.doi.org/10.1016/s0301-9268(01)00149-8.

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16

SHORT, ANDREW EDWARD Z., MAURICIO GARCÍA, and JENNIFER C. GIRÓN. "Revision of the Neotropical water scavenger beetle genus Globulosis García, 2001 (Coleoptera: Hydrophilidae: Acidocerinae)." Zootaxa 4232, no. 2 (2017): 271. http://dx.doi.org/10.11646/zootaxa.4232.2.10.

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The Neotropical water scavenger beetle genus Globulosis García, 2001 is revised. Originally described from a single male specimen from southeastern Venezuela, the genus has since been found in localities across the Guiana Shield region and beyond, including Colombia, Suriname, Guyana, and Brazil. The genus is redescribed. Morphological characters and genetic data from the mitochondrial gene COI from ten populations across its range provide support for two distinct species, corresponding loosely to geography. The type species, G. hemisphericus García, is redescribed and newly recorded from Guyana, Suriname, and Brazil (Amazonas, Para). One new species is described, Globulosis flavus sp. n. from southwestern Venezuela (Amazonas, Bolivar). The genus is associated with lotic habitats, and typically found along the margins of small to medium sized streams. High-resolution habitus and aedeagal images and distribution maps for all species are provided.

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17

Armenteras, Dolors, Nelly Rodríguez, and Javier Retana. "Are conservation strategies effective in avoiding the deforestation of the Colombian Guyana Shield?" Biological Conservation 142, no. 7 (2009): 1411–19. http://dx.doi.org/10.1016/j.biocon.2009.02.002.

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18

Spier, C. A., and C. F. Ferreira Filho. "The Chromite Deposits of the Bacuri Mafic-Ultramafic LayeredComplex, Guyana Shield, Amapa State, Brazil." Economic Geology 96, no. 4 (2001): 817–35. http://dx.doi.org/10.2113/gsecongeo.96.4.817.

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19

Arbour, Jessica H., and Hernán López-Fernández. "Guianacara dacrya, a new species from the rio Branco and Essequibo River drainages of the Guiana Shield (Perciformes: Cichlidae)." Neotropical Ichthyology 9, no. 1 (2011): 87–96. http://dx.doi.org/10.1590/s1679-62252011000100006.

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A new species of Guianacara is described from tributaries of the Essequibo River and the rio Branco in Guyana and northern Brazil. Guianacara dacrya, new species, can be diagnosed from all congeners by the possession of a unique infraorbital stripe and by the shape of the lateral margin of the lower pharyngeal jaw tooth plate. Guianacara dacrya can be further distinguished from G. geayi, G. owroewefi, G. sphenozona and G. stergiosi by the possession of a thin midlateral bar, from G. cuyunii by the possession of dusky branchiostegal membranes and from G. oelemariensis by the possession of two supraneurals. This species differs from most congeners by the presence of white spots on the spiny portion of the dorsal fin, the placement of the midlateral spot, the presence of filaments on the dorsal, anal and in rare cases the caudal-fin and from at least the Venezuelan species by several morphometric variables. Guianacara dacrya is known from the Essequibo, Takutu and Ireng River basins of Guyana and possibly from the rio Uraricoera in the rio Branco basin in Brazil. A key to the species is provided.

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20

Da Costa e Silva, Natali Fabiana. "Women's place of speech in the literature of Suriname: challenging gender and race paradigms." Letras Escreve 9, no. 2 (2020): 79. http://dx.doi.org/10.18468/letras.2019v9n2.p79-85.

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Suriname is located in the extreme north of South America in a region called Guyana Shield, that includes French Guiana, Republic of Guyana, Suriname and part of Venezuela and northern Brazil. It’s literature is marked by cultural and linguistic ethnic plurality and the thematization of social contradictions. In the case of the literature of Suriname, the narratives that compose this space inscribed in the heterogeneity are populated by characters historically silenced, as enslaved women, workers of the plantations, "bushnengués", among others, but who speak, despite being intermediated by a writer, as representatives of cultures not valued and/or little known. In this sense, this article will discuss two Surinamese historical novels written by Cynthia McLeod,<em>The free negress Elisabeth: prisoner of color</em> (2004) and <em>Tutuba: the girl from the slave-shipLeudsen</em>(2013), addressing, more specifically, how her literature questions the current literary paradigms and discusses the problematic of women’s voices, whose legitimacy is continually put in question.

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Spier, C. A. "The Chromite Deposits of the Bacuri Mafic-Ultramafic Layered Complex, Guyana Shield, Amapa State, Brazil." Economic Geology 96, no. 4 (2001): 817–35. http://dx.doi.org/10.2113/96.4.817.

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22

CALDERÓN-ESPINOSA, MARTHA LUCIA, and GUIDO FABIAN MEDINA-RANGEL. "A new Lepidoblepharis lizard (Squamata: Sphaerodactylidae) from the Colombian Guyana shield." Zootaxa 4067, no. 2 (2016): 215. http://dx.doi.org/10.11646/zootaxa.4067.2.6.

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23

Kok, Philippe, and Gilson Rivas Fuenmayor. "Typhlophis ayarzaguenai Señaris, 1998 is a junior synonym of Typhlophis squamosus (Schlegel, 1839)." Amphibia-Reptilia 29, no. 4 (2008): 555–58. http://dx.doi.org/10.1163/156853808786230406.

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AbstractIn 1839, Schlegel described Typhlophis squamosus on the basis of a single specimen from Cayenne, French Guiana. Since then the species has been reported from Brazil, Guyana and Suriname. Relying only on the original description and a subsequent short description of the holotype of T. squamosus by Boulenger in 1893, Señaris described T. ayarzaguenai from Venezuela in 1998. Señaris' description of T. ayarzaguenai contains several errors and discrepancies and we argue that our observations justify the consideration of T. ayarzaguenai as a junior synonym of T. squamosus. The genus Typhlophis thus remains monotypic and T. squamosus is a widespread species in the Guiana Shield.

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24

KOK, PHILIPPE J. R., D. BRUCE MEANS, and FRANKY BOSSUYT. "A new highland species of Pristimantis Jiménez de la Espada, 1871 (Anura: Strabomantidae) from the Pantepui region, northern South America." Zootaxa 2934, no. 1 (2011): 1. http://dx.doi.org/10.11646/zootaxa.2934.1.1.

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A new strabomantid frog of the genus Pristimantis Jiménez de la Espada, 1871 is described from the Eastern Pantepui Region, Guiana Shield, northern South America. The new species, Pristimantis aureoventris sp. nov., is known so far from two neighbouring tepuis, namely Wei Assipu Tepui (type locality) at the border between Guyana and Brazil and Mount Roraima in Guyana, and occurs between 2210–2305 m elevation. The new taxon is distinguished from all known congeners by the following combination of characters: Finger I < II; tympanum distinct; basal webbing between Toes IV-V; broad lateral fringes on fingers and toes; ventral skin areolate; vocal slits absent in male; two non-spinous whitish nuptial pads and vocal sac present in male; high degree of pattern polymorphism; throat, chest, and belly golden yellow, usually with reddish brown to dark brown mottling; internal organs little or not visible through the ventral skin in life. The call of the new species consists of bouts of a single amplitude-modulated (decreasing to the end) note repeated at a rate of ca. 18 notes/min with a dominant frequency ranging from 2180 to 2430 Hz.

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FREITAS, JOELCIO, FAVIO GONZÁLEZ, ODILE PONCY, CHRISTIAN FEUILLET, and ANDERSON ALVES-ARAÚJO. "Floral geometric morphometrics unveils a new cauliflorous species of Aristolochia (Aristolochiaceae) from the Guiana Shield." Phytotaxa 474, no. 1 (2020): 1–14. http://dx.doi.org/10.11646/phytotaxa.474.1.1.

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Aristolochia wankeana (Aristolochiaceae), a new species from French Guiana and Guyana, is described and illustrated here. Floral traits, primarily of the shape and size of the perianth limb, examined through a morphometric geometric analysis, are diagnostic to distinguish the new species from its relatives A. cornuta and A. iquitensis. The species belongs to Aristolochia subser. Anthocaulicae, characterized by having extremely short cauliflorous racemes with scale-like, triangular subtending bracts. This is the first study that uses morphometrics for taxonomic purposes in Aristolochia, an approach that becomes promising to solve species complexes in this genus.

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26

Schuster, Rudolf M. "Origins of Neotropical Leafy Hepaticae." Bryophyte Diversity and Evolution 2, no. 1 (1990): 239–64. http://dx.doi.org/10.11646/bde.2.1.20.

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The neotropical hepatic flora, predominantly constituted by members of the Jungermanniales and Metzgeriales, includes a disproportionate number of genera which are endemic (over 38) and a number which evidently originated here but have shown slight and in a geological sense, modern dispersal by solitary species. Endemism is confined almost to the Jungermanniales; it is to a large degree of a unique sort: confined to highly apomorphic derivatives, often extremely reduced, sometimes confervoid or thalloid (aside from ‘normal’ sexual branches). These endemics are derivatives of basically cool-Gondwanalandic suborders, chiefly Lepidoziineae and Cephaloziineae which, in the Antipodes today include a wide range of plesiomorphic taxa. The highest proportion of endemic genera, often stenotypic (1-3 species each) occurs in the upper montane zone: from upper Andean forest to páramo, to the edge of permanent snow and ice; a smaller number occurs at upper elevations of the Guyana Shield, but more occur in the riverine systems that dissect this shield. The taxa found there (i.a., Zoopsidella, Pteropsiella, Schusterolejeunea, Cephalantholejeunea) are among the most apomorphic of all hepatics.

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McReath, Ian, and Maria Telma Lins Faraco. "Paleoproterozoic greenstone-granite belts in Northern Brazil and the former Guyana Shield - West African Craton province." Geologia USP. Série Científica 5, no. 2 (2006): 49–63. http://dx.doi.org/10.5327/s1519-874x2006000100004.

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Silverstein, J., M. Krekeler, and J. Rakovan. "Morphologic Evidence of In-Situ Gold Deposition in Lateritic Placer Deposits from Guyana Shield of Venezuela." Microscopy and Microanalysis 22, S3 (2016): 2014–15. http://dx.doi.org/10.1017/s1431927616010916.

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29

Labat, D., J. C. Espinoza, J. Ronchail, et al. "Fluctuations in the monthly discharge of Guyana Shield rivers, related to Pacific and Atlantic climate variability." Hydrological Sciences Journal 57, no. 6 (2012): 1081–91. http://dx.doi.org/10.1080/02626667.2012.695074.

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30

Mendes Pontes, Antonio Rossano, Antonio Paulo da Silva Júnior, and David Chivers. "The occurrence of leucism in groups of tayras Eira barbara Linnaeus 1758 on the Guyana shield." Écoscience 27, no. 4 (2020): 295–301. http://dx.doi.org/10.1080/11956860.2020.1804724.

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31

McPherson, Tsitsi Y. "Landscape scale species distribution modeling across the Guiana Shield to inform conservation decision making in Guyana." Biodiversity and Conservation 23, no. 8 (2014): 1931–48. http://dx.doi.org/10.1007/s10531-014-0696-4.

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32

Milhomem Neto, João Marinho, and Jean-Michel Lafon. "Zircon U-Pb and Lu-Hf isotope constraints on Archean crustal evolution in Southeastern Guyana Shield." Geoscience Frontiers 10, no. 4 (2019): 1477–506. http://dx.doi.org/10.1016/j.gsf.2018.09.012.

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33

LASSO-ALCALÁ, OSCAR M., DONALD C. TAPHORN B., CARLOS A. LASSO, and OSCAR LEÓN-MATA. "Rivulus sape, a new species of killifish (Cyprinodontiformes: Rivulidae) from the Paragua River system, Caroní River drainage, Guyana Shield, Venezuela." Zootaxa 1275, no. 1 (2006): 21. http://dx.doi.org/10.11646/zootaxa.1275.1.2.

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A new species, Rivulus sape, is described from two tributaries of the upper Paragua River, Caroní River drainage, of the Guyana Shield in Venezuela. It is a small (all specimens examined less than 50 mm SL), apparently non-annual species that is distinguished from congeners in having the dorsal, anal, and pelvic fins short; adult males with a truncate caudal fin with the upper and lower borders black; and an iridescent blue, ovate spot on sides of the body above the pectoral fins. Neither adults nor juveniles have an ocellus at the dorsal junction of the caudal peduncle and caudal fin. Only one contact organ per scale on some scales along the sides of the body was observed.

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Almeida, Marcelo E., Moacir J. B. Macambira, and Sérgio de C. Valente. "New geological and single-zircon Pb evaporation data from the Central Guyana Domain, southeastern Roraima, Brazil: Tectonic implications for the central region of the Guyana Shield." Journal of South American Earth Sciences 26, no. 3 (2008): 318–28. http://dx.doi.org/10.1016/j.jsames.2008.08.003.

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35

Feldpausch, T. R., J. Lloyd, S. L. Lewis, et al. "Tree height integrated into pan-tropical forest biomass estimates." Biogeosciences Discussions 9, no. 3 (2012): 2567–622. http://dx.doi.org/10.5194/bgd-9-2567-2012.

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Abstract. Above-ground tropical tree biomass and carbon storage estimates commonly ignore tree height. We estimate the effect of incorporating height (H) on forest biomass estimates using 37 625 concomitant H and diameter measurements (n = 327 plots) and 1816 harvested trees (n = 21 plots) tropics-wide to answer the following questions: 1. For trees of known biomass (from destructive harvests) which H-model form and geographic scale (plot, region, and continent) most reduces biomass estimate uncertainty? 2. How much does including H relationship estimates derived in (1) reduce uncertainty in biomass estimates across 327 plots spanning four continents? 3. What effect does the inclusion of H in biomass estimates have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of the destructively harvested trees was half (mean 0.06) when including H, compared to excluding H (mean 0.13). The power- and Weibull-H asymptotic model provided the greatest reduction in uncertainty, with the regional Weibull-H model preferred because it reduces uncertainty in smaller-diameter classes that contain the bulk of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows errors are reduced from 41.8 Mg ha−1 (range 6.6 to 112.4) to 8.0 Mg ha−1 (−2.5 to 23.0) when including $H$. For all plots, above-ground live biomass was 52.2±17.3 Mg ha−1 lower when including H estimates (13%), with the greatest reductions in estimated biomass in Brazilian Shield forests and relatively no change in the Guyana Shield, central Africa and southeast Asia. We show fundamentally different stand structure across the four forested tropical continents, which affects biomass reductions due to $H$. African forests store a greater portion of total biomass in large-diameter trees and trees are on average larger in diameter. This contrasts to forests on all other continents where smaller-diameter trees contain the greatest fractions of total biomass. After accounting for variation in $H$, total biomass per hectare is greatest in Australia, the Guyana Shield, and Asia and lowest in W. Africa, W. Amazonia, and the Brazilian Shield (descending order). Thus, if closed canopy tropical forests span 1668 million km2 and store 285 Pg C, then the overestimate is 35 Pg C if H is ignored, and the sampled plots are an unbiased statistical representation of all tropical forest in terms of biomass and height factors. Our results show that tree $H$ is an important allometric factor that needs to be included in future forest biomass estimates to reduce error in estimates of pantropical carbon stocks and emissions due to deforestation.

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CABRAL, FERNANDA NUNES, VOLKER BITTRICH, and MARIA DO CARMO ESTANISLAU DO AMARAL. "Four new species of Caraipa (Calophyllaceae) from the Amazon basin and the Guiana Shield." Phytotaxa 286, no. 4 (2016): 245. http://dx.doi.org/10.11646/phytotaxa.286.4.3.

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Four new species of Caraipa (Calophyllaceae) are described and illustrated: Caraipa balbinensis, endemic to Balbina (Presidente Figueiredo, Amazonas, Brazil), C. caespitosa growing in savannah and white-sand vegetation in Roraima and Amazonas (Brazil), Guainía (Colombia) and Amazonas (Venezuela), C. davilae, an endemic species of Loreto (Peru), and C. macrocarpa, an endemic species to Guyana. Morphological comparisons with the similar taxa are provided for each new species: C. balbinensis can be distinguished from C. heterocarpa by its longer leaves and petioles, and its slightly rugulose fruit surface; C. caespitosa can be separated from C. grandifolia and C. longipedicellata by its distinguished habit, and its smaller leaves and inflorescences; C. davilae differs from C. balbinensis and C. grandifolia by its dense indument on the abaxial leaf surface, and its rugulose and concave fruit valves; and C. macrocarpa can be distinguished from C. punctulata by its large, glabrous and rugulose fruits.

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Palenova, E. E., K. A. Novoselov, and E. V. Belogub. "Gold in weathering mantle of the Guiana shield (South America)." МИНЕРАЛОГИЯ (MINERALOGY) 5 (July 16, 2019): 83–100. http://dx.doi.org/10.35597/2313-545x-2019-5-2-83-100.

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The article describes mineral composition of laterite weathering mantle overlapping the Amamuri and Kontakt gold deposits in the greenstone rocks, located 20 km southeast of the Aurora deposit (reserves of 185 tons Au, Republic of Guyana). The major minerals of the weathering mantle include disordered kaolinite (35–90 wt. %), relict quartz and hydromica (up to 20 wt. % illite). The heavy concentrate is represented by limonite (up to 8 wt. % goethite), magnetite, hematite, ilmen-ite, anatase, ferrous rutile, psilomelane, pyrite, chalcopyrite, galena, sphalerite, covellite, zircon, tourmaline, epidote and amphibole. Native gold composes signifcant amount of heavy concentrates (up to 9 wt. %) and includes the following types: 1) lode gold in relict quartz veins and stockwork, 2) relict gold in laterite and 3) supergene gold. According to mineralogical studies, moderate late-ritization and monosialitization processes are probably due to erosion of ancient areal weathering mantle and the presence of immature laterites over the Amamuri and Kontakt deposits. Most amount of gold is relic. The processes of its redeposition and supergene alterations are weak. The dominant size of gold grains of <100 µm makes gravitational concentration of laterites more difcult, whereas weakly ordered kaolinite prevents agglomeration during cyanidation and heap leaching. Alluvial placers are probably more promising for exploration, since they provide natural fractionation of gold particles by size favorable for gravity extraction.

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FARROÑAY, FRANCISCO, MARISABEL U. ADRIANZÉN, RICARDO DE OLIVEIRA PERDIZ, and ALBERTO VICENTINI. "A new species of Macrolobium (Fabaceae, Detarioideae) endemic on a Tepui of the Guyana Shield in Brazil." Phytotaxa 361, no. 1 (2018): 97. http://dx.doi.org/10.11646/phytotaxa.361.1.8.

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Macrolobium aracaense (Fabaceae), a new endemic treelet species from Brazil, is here described and illustrated. Morphologically it is similar to M. longipes: both are treelets, the leaflets have the same shape and are covered by papillary epidermis on the abaxial surface, and the sepals apex are minutely ciliate. Macrolobium aracaense occurs in sympatry with M. discolor var. discolor and M. gracile var. confertum in Serra do Aracá State Park, Amazonas, Brazil, and these four species can be easily differentiated by morphological characters, and their similarities and differences are here discussed.

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Schulze, Daniel J., Dante Canil, Dominic M. DeR Channer, and Felix V. Kaminsky. "Layered mantle structure beneath the western Guyana Shield, Venezuela: Evidence from diamonds and xenocrysts in Guaniamo kimberlites." Geochimica et Cosmochimica Acta 70, no. 1 (2006): 192–205. http://dx.doi.org/10.1016/j.gca.2005.08.025.

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Bassoo, Roy, Kenneth S. Befus, Peng Liang, Steven L. Forman, and Glenn Sharman. "Deciphering the Enigmatic Origin of Guyana's Diamonds." American Mineralogist 106, no. 1 (2021): 54–68. http://dx.doi.org/10.2138/am-2020-7486.

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Abstract Diamonds have long been mined from alluvial terrace deposits within the rainforest of Guyana, South America. No primary kimberlite deposits have been discovered in Guyana, nor have there been previous studies on the mineralogy and origin of the diamonds. Paleoproterozoic terranes in Guyana are prospective to diamond occurrences because the most productive deposits are associated spatially with the eastern escarpment of the Paleoproterozoic Roraima Supergroup. Geographic proximity suggests that the diamonds are detrital grains eroding from the &lt;1.98 Ga conglomerates, metamorphosed to zeolite and greenschist facies. The provenance and paragenesis of the alluvial diamonds are described using a suite of placer diamonds from different locations across the Guiana Shield. Guyanese diamonds are typically small, and those in our collection range from 0.3 to 2.7 mm in diameter; octahedral and dodecahedral, with lesser cubic and minor macle forms. The diamonds are further subdivided into those with abraded and non-abraded surfaces. Abraded diamonds show various colors in cathodoluminescence, whereas most non-abraded diamonds appear blue. In all populations, diamonds are predominantly colorless, with lesser brown to yellow and very rare white. Diamonds are predominantly Type IaAB and preserve moderate nitrogen aggregation and total nitrogen concentrations ranging from trace to ~1971 ppm. The kinetics of nitrogen aggregation indicate mantle-derived residence temperatures of 1124 ± 100 °C, assuming residence times of 1.3 and 2.6 Ga for abraded and non-abraded diamonds, respectively. The diamonds are largely sourced from the peridotitic to eclogitic lithospheric upper mantle based on both δ13C values of –5.82 ± 2.45‰ (VPDB-LSVEC) and inclusion suites predominantly comprised of forsterite, enstatite, Cr-pyrope, chromite, rutile, clinopyroxene, coesite, and almandine garnet. Detrital, accessory minerals are non-kimberlitic. Detrital zircon geochronology indicates diamondiferous deposits are predominantly sourced from Paleoproterozoic rocks of 2079 ± 88 Ma.

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Lim, Burton, and Thomas Lee. "Community Ecology and Phylogeography of Bats in the Guianan Savannas of Northern South America." Diversity 10, no. 4 (2018): 129. http://dx.doi.org/10.3390/d10040129.

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The Guiana Shield of South America contains savannas within one of the largest contiguous expanses of pristine tropical rainforest remaining in the world, but biodiversity in the grasslands is poorly known. In lowland Neotropical areas, bats typically comprise the most species-rich group of mammals. We compare the bat faunal community and phylogeography in the savanna habitats of the Llanos in Venezuela, Rupununi in Guyana, and Sipaliwini in Suriname. Measures of species diversity and relative abundance from standardized field survey methodology enable comparison among these three grassland regions. Genetic variation is summarized by DNA barcoding to examine biogeographic patterns across larger forest–savanna landscapes. A total of 76 species of bats is documented, of which 18 species are reported from all 3 savannas and 30 species are reported from only 1 of the savannas. Endemism is low with 5 taxa restricted primarily to dry, open habitats. However, 7 other species have divergent phylogeographic lineages associated with savanna populations. Although bat species are usually distributed over wide regions of the Neotropics, the habitat mosaics of the Guiana Shield have different faunal assemblages. Going back into the Miocene, the contractions and expansions of forest–savanna paleoenvironments over time have contributed to speciation and the current high levels of biodiversity in South America.

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Valério, Cristóvão da Silva, Valmir da Silva Souza, and Moacir José Buenano Macambira. "The 1.90–1.88Ga magmatism in the southernmost Guyana Shield, Amazonas, Brazil: Geology, geochemistry, zircon geochronology, and tectonic implications." Journal of South American Earth Sciences 28, no. 3 (2009): 304–20. http://dx.doi.org/10.1016/j.jsames.2009.04.001.

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KOK, PHILIPPE J. R. "A new species of the genus Gonatodes Fitzinger, 1843 (Reptilia: Sphaerodactylidae) from central Guyana, northern South America." Zootaxa 3018, no. 1 (2011): 1. http://dx.doi.org/10.11646/zootaxa.3018.1.1.

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A new sphaerodactyl lizard of the genus Gonatodes Fitzinger, 1843 is described from the Iwokrama Forest Reserve, central Guyana, Guiana Shield, northern South America. The new species, Gonatodes timidus sp. nov., is known so far from the type locality only, at ca. 210 m elevation. The new taxon is mainly distinguished from all known congeners by the following combination of characters: moderate body size, absence of a clearly differentiated elongate supraciliary spine, absence of clusters of distinctly enlarged conical scales on sides, escutcheon scales on posterior belly and ventral surfaces of thighs in males evident, three to four lateral rows of scales on distal part of fingers and toes, medial subcaudal scales distinctly differentiated from adjacent scales on non-regenerated tail (in a 1’1” sequence), and obvious sexual dichromatism, the males having the upper surface of the head black with bluish white to vivid yellow irregular stripes and blotches.

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Provenzano R., Francisco, Antonio Machado-Allison, Barry Chernoff, Phil Willink, and Paulo Petry. "Harttia merevari, a new species of catfish (Siluriformes: Loricariidae) from Venezuela." Neotropical Ichthyology 3, no. 4 (2005): 519–24. http://dx.doi.org/10.1590/s1679-62252005000400009.

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Harttia merevari, a new species of loricariid catfish, is described from eight specimens captured in the upper Caura River, Orinoco River basin, Venezuela. The new species is recognized by the following combination of characters: abdomen naked; two or three preanal plates; a bony plate before each branchial opening; seven lateral plates between the pectoral and pelvic fins; maxillary barbel short and attached to the oral disk by a fleshy fold; head dorsal surface and anterior portion of the body light or dark yellow with numerous, round black spots; posterior region of the body light or dark yellow with five black transverse bands, dorsal central area of the two anterior bands diffused. The discovery of this new species extends the distribution of the genus northwest to include the Orinoco River basin on the northern slope of the Guyana shield.

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COSTA-CAMPOS, CARLOS EDUARDO, and THIAGO RIBEIRO DE CARVALHO. "The advertisement call of the Hoogmoed’s harlequin toad Atelopus hoogmoedi Lescure, 1974 from northern Brazil (Anura, Bufonidae)." Zootaxa 4521, no. 1 (2018): 141. http://dx.doi.org/10.11646/zootaxa.4521.1.11.

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Harlequin toads (Atelopus) are distributed over a wide range in the Amazon Rainforest, mostly associated with streamlets in dense ombrophilous forests in lowland and sub-montane regions. Atelopus hoogmoedi Lescure, 1974a was considered as bearing full species status by Lötters et al. (2005), although until that moment this species had been assigned to a subspecies of A. pulcher (Boulenger, 1882) (Lescure 1974a, 1976) or of A. spumarius Cope, 1871 (Lescure et al. 1980; Lescure & Marty 2000; Lötters et al. 2002). More recently, Noonan & Gaucher (2005) subscribed to Lötters et al. (2005)’s statement that A. s. hoogmoedi should belong to a distinctive species (A. hoogmoedi), based on phylogeographic evidence. The species’ range is currently restricted to the Guiana Shield of French Guiana, Suriname, Guyana, and in adjacent regions of northern Brazil (Lötters et al. 2005).

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CRAMPTON, WILLIAM G. R., and JAMES S. ALBERT. "Redescription of Gymnotus coropinae (Gymnotiformes, Gymnotidae), an often misidentified species of Neotropical electric fish, with notes on natural history and electric signals." Zootaxa 348, no. 1 (2003): 1. http://dx.doi.org/10.11646/zootaxa.348.1.1.

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Gymnotus coropinae, a diminutive species of Neotropical electric fish, was originally described by Hoedeman from Surinam. Shortly after its description, G. coropinae was synonymized with a syntopic congener, G. anguillaris. Here we redescribe G. coropinae as a valid species distinguishable from all congeners by a unique color pattern comprised of a dark brown background color marked by 8–18 white or pale yellow bands that in the anterior 1/3 to 2/3 of body are absent or largely restricted to the ventral part of the lateral surface. Gymnotus coropinae is further distinguishable from G. anguillaris and other congeners on the basis of several meristic and morphometric characters. Gymnotus coropinae is widely distributed throughout the Amazon and Orinoco Basins and the Guyana Shield. It inhabits small terra firme forest streams and swamps containing acidic, low-conductivity water.

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Assumpção, Marcelo, and Alberto V. Veloso. "The 1885 M 6.9 Earthquake in the French Guiana–Brazil Border: The Largest Midplate Event in the Nineteenth Century in South America." Seismological Research Letters 91, no. 5 (2020): 2497–510. http://dx.doi.org/10.1785/0220190325.

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Abstract In 4 August 1885, 06:30 local time, a strong earthquake (reported intensities up to VI–VII modified Mercalli intensity [MMI]) was felt in the French Guiana, causing slight damage. Recently discovered newspaper records show that this event was also felt as far as Georgetown (British Guyana), Belém, and several other localities along the Amazon River toward Manaus (Brazil). The distribution of intensities and the radius of the felt area indicate a magnitude around Mw 6.9, which makes it the largest known earthquake in the stable continental region of South America, since the nineteenth century. The epicenter, determined with four different attenuation relations, lies onshore near the border between the French Guiana and Brazil, although an epicenter offshore in the continental slope cannot be ruled out with 95% confidence. The epicenter (03.4° N, 52.9°W±100 km) likely lies in the Transamazonian (2.2–2.0 Ga) geochronological province in the Guyana shield of the Amazon craton. No nearby failed rift is known onshore near the epicenter, which would place this event in the ∼30% class of nonextended stable continental crust. Other nearby smaller earthquakes (both historical and instrumental) with magnitudes up to mb 5.2, indicate a cluster of seismicity in the region of the 1885 earthquake, possibly delineating an onshore seismic zone separate from the sparse seismicity along the continental shelf. This large midplate earthquake will likely affect future reevaluations of seismic hazard in midplate South America.

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Epelboin, Loïc, Carole Eldin, Pauline Thill, et al. "Human Q Fever on the Guiana Shield and Brazil: Recent Findings and Remaining Questions." Current Tropical Medicine Reports 8, no. 3 (2021): 173–82. http://dx.doi.org/10.1007/s40475-021-00243-4.

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Abstract Purpose of Review In this review, we report on the state of knowledge about human Q fever in Brazil and on the Guiana Shield, an Amazonian region located in northeastern South America. There is a contrast between French Guiana, where the incidence of this disease is the highest in the world, and other countries where this disease is practically non-existent. Recent Findings Recent findings are essentially in French Guiana where a unique strain MST17 has been identified; it is probably more virulent than those usually found with a particularly marked pulmonary tropism, a mysterious animal reservoir, a geographical distribution that raises questions. Summary Q fever is a bacterial zoonosis due to Coxiella burnetii that has been reported worldwide. On the Guiana Shield, a region mostly covered by Amazonian forest, which encompasses the Venezuelan State of Bolivar, Guyana, Suriname, French Guiana, and the Brazilian State of Amapá, the situation is very heterogeneous. While French Guiana is the region reporting the highest incidence of this disease in the world, with a single infecting clone (MST 117) and a unique epidemiological cycle, it has hardly ever been reported in other countries in the region. This absence of cases raises many questions and is probably due to massive under-diagnosis. Studies should estimate comprehensively the true burden of this disease in the region.

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KOK, PHILIPPE J. R., and SANTIAGO CASTROVIEJO-FISHER. "Glassfrogs (Anura: Centrolenidae) of Kaieteur National Park, Guyana, with notes on the distribution and taxonomy of some species of the family in the Guiana Shield." Zootaxa 1680, no. 1 (2008): 25. http://dx.doi.org/10.11646/zootaxa.1680.1.2.

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We provide new distribution records and discuss the taxonomy of three species of Glassfrogs from the Guiana Shield: Centrolene gorzulai, Cochranella helenae, and Hyalinobatrachium taylori. These three species were collected in Kaieteur National Park in west-central Guyana. Taxonomic changes were based on morphological, bioacoustic and genetic (a fragment of the mitochondrial ribosomal gene 16S) comparisons. We consider Centrolene papillahallicum to be a junior synonym of C. gorzulai. We assign the Venezuelan population of Cochranella oyampiensis to Co. helenae and describe the phenotypic variation of this taxon. We refine the description of Cochranella oyampiensis and transfer it to the Co. spinosa species group. We propose the new name Cochranella helenae Group for those species of Cochranella assigned to the former Co. oyampiensis Group. We report the first record of Cochranella midas for French Guiana, and the first record of Hyalinobatrachium nouraguense, new emendation, for Suriname.

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SILVA, DIEGO NUNES DA, FERNANDA RIBEIRO DE MELLO FRAGA, and MARIANA HENRIQUES SANTANA. "Typification of Nietneria corymbosa (Nartheciaceae), the type of the generic name." Phytotaxa 474, no. 2 (2020): 185–90. http://dx.doi.org/10.11646/phytotaxa.474.2.9.

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Nietneria is the only neotropical genus of Nartheciaceae, represented by two species: N. corymbosa and N. paniculata. The collections of the brothers Moritz Richard and Robert Hermann Schomburgk in the Guiana Shield are the first records of special value for Botany, Zoology, and Mineralogy in this region. The brothers carried out an important set of botanical collections for the Guyana flora, in different periods and expeditions, which were organized in different series. Among these, the “Robert’s second collection series (Rob. ser. 2)”, corresponding to the period from 1841 to 1844, which resulted in the discovery of the genus Nietneria. In the present article, we provide a proper designation of a lectotype for Nietneria corymbosa, as a result of an ongoing monograph for the genus in Brazilian Flora 2020 Project. Along with this typification of the type of Nietneria, we provide important historical about original materials.

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