5 results on '"Lucas, R."'
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2. Taxonomic loss and functional reduction over time in the ichthyofauna of the Taquaruçu Reservoir, lower Paranapanema River, Southern Brazil.
- Author
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Ferraz, João D., Casimiro, Armando C. R., Garcia, Diego A. Z., Pereira, Alan D., Jarduli, Lucas R., de Almeida, Fernanda S., and Orsi, Mário L.
- Subjects
MULTIDIMENSIONAL scaling ,FISH communities ,MIGRATORY animals ,FISHING villages ,BIOLOGICAL invasions - Abstract
Copyright of Neotropical Ichthyology is the property of Neotropical Ichthyology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
- Full Text
- View/download PDF
3. Pan-African granitic magmatism of the Kaoko Belt: Tectonic perspective from its South American connection and insights into the crustal architecture of SW Gondwana.
- Author
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Hueck, Mathias, Basei, Miguel A.S., Frimmel, Hartwig, Lino, Lucas M., Corrêa, Vinicius X., Tesser, Lucas R., Campos Neto, Mario C., and Ganade, Carlos E.
- Subjects
- *
SHEAR zones , *ISOTOPIC signatures , *MAGMATISM , *OROGENY , *ISOTOPIC analysis , *BATHOLITHS , *ARCHAEAN ,GONDWANA (Continent) - Abstract
• First orogen-wide investigation of the magmatism, based on new and compiled data. • Strengthens correlation with magmatism in the South American Dom Felicano Belt. • "Crust-like" isotopic signatures are in fact much more juvenile than rest of orogen. • Suggests important mantle input at some point after the Paleoproterozoic. The Kaoko Belt in northwestern Namibia formed during the assembly of Gondwana in the Neoproterozoic to Cambrian Pan-African orogenic cycle. The belt has a complex tectonic architecture, in which a variety of basement units and metasedimentary associations became juxtaposed along shear zones and experienced widespread intrusive magmatism, generally confined to its western domain. We present a large new dataset of whole-rock geochemical and isotope data, as well as U-Pb zircon ages, encompassing a wide variety of granitoids and subordinate basic rocks across the Kaoko Belt. This is complemented by whole-rock isotope analyses from various basement and metasedimentary units and by a compilation of data from the literature. The new dataset strengthens previous models that correlate the granitoids in the Kaoko Belt to the coeval Florianópolis Batholith in the South American Dom Feliciano Belt, which we use to shed new light on the tectonic organization and evolution of the Pan-African orogenic cycle in the Neoproterozoic. The similarities in the compositional range of granitoids from both sub-domains of the Western Kaoko Belt, namely the Orogen Core and the Coastal Terrane, suggest that the entire zone comprises a heterogeneous but comparable and consistently diverse association of rocks. The comparison to South America underscores that, while the granitoids have "crust-like" isotopic signatures, these are in sharp contrast with those of the mostly Archean to Paleoproterozoic basement rocks of both the Kaoko and Dom Felicano belts. This suggests that the magmatic sources of the intrusive magmatism of the Kaoko Belt are likely a mixture of autochthonous crustal melting with an important mantle-derived input at some point after the Paleoproterozoic. This input was probably driven by accretionary orogeny and/or rifting that took place in the Tonian, Ediacaran, or both. The presence of more juvenile associations in the western domain of the Kaoko Belt may indicate an isotopic boundary within the belt that mirrors the tectonic configuration of the Dom Feliciano Belt in South America. This isotopic border, which would correspond to the Puros Shear Zone, could have acted as a terrane boundary from the earliest stages of the tectonic evolution of the Kaoko Belt. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. A new vertebrate ichnological association sheds light on the small metatherian record of the Middle Miocene in South America.
- Author
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Krapovickas, Verónica, Vera, Rocío B., Farina, Martín E., Fernandez Piana, Lucas R., and Koelewijn, Anne
- Subjects
- *
SHORE birds , *MIOCENE Epoch , *VERTEBRATES , *TURTLES , *TRACE fossils , *REPTILES , *ALLUVIUM - Abstract
Vertebrate ichnological associations recorded in Middle Miocene successions were unknown in South America. During that time, South America was isolated from other continents and had a unique endemic fauna and flora. The lower Vinchina succession occurred between 15.6 and 12.7 Ma and records the footprints of highly specialized mammals, reptiles, and birds for the first time. To identify all footprint producers, we focused on anatomical traits of the appendicular skeleton represented on the footprints together with body size estimations of the producers as body mass and the apparent trunk length (GAD). Carnivoripeda sudamericana nov. isp. reveals a weasel-like producer of ∼1 kg and a trunk length of 19–26 cm most likely attributed to metatherian carnivores (Sparassodonta). They represent the oldest carnivore footprints in South America. Small bipedal rodent-like mammals of ∼280 g using a jumping gait (Morphotype A) are interpreted as produced by highly specialized South American marsupials, argyrolagids, whose footprints were unknown until now. Other mammalian footprints recorded are Tacheria troyana most likely produced by dinomyid caviomorph rodents. They represent animals of ∼16 kg and a trunk length of 48–55 cm, like living dinomyids. Subcircular to oval structures (Morphotype B) seems to be produced by medium-sized ungulates, while stepping in cohesive and plastic soupy sediments. cf. Chelonipus torquatus suggests small freshwater turtles (Chelidae or Podocnemididae), of ∼400 g consistent with a trackmaker of carapace size of ∼9 cm. Aviadactyla vialovi was most likely produced by a small shorebird (Scopolacidae) of ∼40 g. All footprints are preserved on crevasse splay deposits of anastomosing fluvial systems together with meniscate feeding (Taenidium barretti) and simple dwelling trace fossils (Palaeophycus tubularis) produced by insects and are an example of the Scoyenia Ichnofacies. [Display omitted] • C. sudamericana nov. isp. may represent the first sparassodont footprints ever found. • C. sudamericana nov. isp. are the oldest carnivore footprints in South America. • First footprints found of highly specialized South American marsupials, argyrolagids • The lower Vinchina succession records South Americas's only well constrained Middle Miocene (15.6–12.7 Ma) ichnoassociation i • The ichnoassociation is dominated by small-sized mammals (sparassodonts and argyrolagids), reptiles (freshwater turtles), and birds (shorebirds), followed by medium-sized, dinomyid rodents and ungulates. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. Can the Herbicide Dicamba Produce Oxidative Stress in the Native South American fish Jenynsia lineata at Environmentally Relevant Concentrations?
- Author
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Villagran DM, Lombardero LR, Crupkin AC, Mendieta JR, Medici SK, Lavarello F, Simoniello MF, and Menone ML
- Subjects
- Animals, Glutathione Transferase, Hydrogen Peroxide, South America, Superoxide Dismutase, Dicamba toxicity, Fishes, Herbicides toxicity, Oxidative Stress
- Abstract
Dicamba (DIC) is one of the most applied auxin herbicides worldwide. Sublethal effects in the South American native fish Jenynsia lineata exposed to DIC concentrations close to environmental concentrations (0.03-30 µg/L) during 48 h were analysed thorough the evaluation of catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD) activities and malondialdehyde (MDA) and H
2 O2 levels for detecting potential oxidative stress. In gills MDA increased showing oxidative damage probably because of an inefficient antioxidant defense. This response evidenced the important role of gills as an organ of direct contact with waterborne contaminants. In addition, other changes in the biomarkers of oxidative stress were observed such as the inhibition of SOD activities in brain and the inhibition of GST in liver. These results show that short- term exposures to environmentally relevant concentrations of DIC could induce sublethal effects in native fish., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)- Published
- 2023
- Full Text
- View/download PDF
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