Fossil deep-sea snapper (Actinopterygii: Lutjanidae) from the Last Interoceanic Central American Deep Strait (LICADS) Orangel Aguilera, Carlos De Gracia, Félix Rodriguez, Olga Oliveira de Araújo, Paulo Andreas Buckup, et al. Swiss Journal of Palaeontology, 2025 Although lutjanid snappers are widely distributed and diverse marine fishes living in tropical America (the Central Western Atlantic and Central Eastern Pacific), no fossil skeletons of Lutjanidae are reported from the Neogene. Here we describe the first specimens of Lutjanidae from the Chagres Sandstone Member of the late Miocene Chagres Formation, located on the Panamanian Caribbean coast. The skull and the postcranial bones of the specimen indicate that it represents an undescribed species of the genus Etelis . The new taxon is characterized by a moderately deep skull with dorsal surface slanted 29 ͦ relative to the horizontal axis, a large orbit, an opercle with a distal margin forming a wide spine, a posterior margin of the preopercle that is serrated without prominent spines, premaxilla and dentary with a single row of dental alveoli. The mouth is slightly oblique, and the body is elongate and slender. The dorsal fin aligns with the pectoral fins, while the pelvic fin is short and does not reach the anal fin. Oceanic water interchange and species dispersal associated with marine currents flowing eastward through the Central American Seaway appear to have driven the diversification of the American Lutjanidae prior to the complete closure of the Panama Isthmus. The palaeoceanographic changes driven by this geological event triggered a faunal turnover that shaped the extant marine diversity in the Caribbean. The newly described lutjanid is associated to a markedly bathyal (200–500 m) archipelagic and interoceanic seaway strait in central Panama (the Last Interoceanic Central American Deep Strait, LICADS). ZooBank LSI: urn:lsid:zoobank.org:pub:30823570-21C4-4685-AFCF-C1C916577ABC
Biogenic carbonate samples: Preliminary tests on chemical protocols for radiocarbon analysis M I Oliveira, C Carvalho, D Tremmel, C Silveira, A A Brito, et al. Radiocarbon, 2025 Most of the carbonate samples have a basic well-defined pretreatment protocol for 14C-AMS dating, but particularities of specific organisms have to be treated with care. This is the case of stromatolite samples, in which carbonate is formed by biogenesis and also has a porous structure that could contain recent organic material as a contaminant. In this work, we analyzed the differences in the radiocarbon content by using organic matter removals before chemical treatment with HCl: sodium hypochlorite (NaOCl) a 0.7M solution with pH ∼11, and hydrogen peroxide (H2O2) an 8.8M solution with pH ∼5. These treatments were chosen because they are the most used in stromatolite samples for geochemical analysis. To compare the impact of the organic matter removal treatments in stromatolite samples we also processed them as regular carbonate samples for radiocarbon analysis, with no organic matter removal (control samples). X-ray diffraction and X-ray fluorescence have been used to obtain mineral and elemental characterization, respectively. H2O2 could not influence the results of Mg-calcite concentrate samples. The use of NaOCl appears to have been effective in preserving more material than H2O2 independent of the mineralogical composition of the stromatolite layers. The F14C results after HCl etching for Mg-calcite concentrated samples were similar to those without etching suggesting that the HCl etching does not impact the results in this case. The organic matter removal is more important than the etching procedure for stromatolite samples. NaOCl is more indicated to be used as chemical pretreatment for radiocarbon analysis purposes independent of the mineral matrix of samples.
Personal computer-based digital petrophysics Ricardo Leiderman, Andre M. B. Pereira, Francisco M. J. Benavides, Carla S. Silveira, Rodrigo M. R. Almeida, et al. Revista Brasileira De Geofisica, 2017
Hydrological relationship between rainfall and discharge temporal range in a multiple land use drainage basin in Teresópolis, RJ, Brazil Geociencias, 2012
