Two new and two resurrected species of the sciaenid genusJohnius (Johnius) from the West Pacific

Sasaki, Kunio

doi:10.1007/bf02905476

Cited by 9 publications

(7 citation statements)

References 7 publications

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“…ERT data were processed using the inverse modeling program RES2DINV (Geotomo Software) (Loke and Barker 1996) to provide estimates of the two-dimensional spatial distribution of resistivity along the survey profile. The inversion algorithm is based on the standard smoothness-constrained least-squares inversion algorithm (Gauss-Newton method) (De Groot-Hedlin and Constable, 1990;Sasaki, 1992). The 2D inversion results were obtained with a RMS error less than 3% and a number of iteration which various from three to six iterations, the low RMS values reflects the high data quality.…”

Section: Methodsmentioning

confidence: 99%

Contribution of geophysics to geometric characterization of freshwater–saltwater interface in the Maâmoura region (NE Tunisia)

Chabaane

Redhaounia

Gabtni

et al. 2018

Euro-Mediterr J Environ Integr

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The Maâmoura aquifer is located on the eastern coast of the Cap Bon peninsula. During recent decades, the agricultural exploitation of water has been strongly reinforced, causing an over-pumping of the groundwater resources accompanied by an intrusion of seawater. The geophysical approach based on electrical resistivity tomography has been adopted to obtain high-resolution electrical sections imaging, which allows delineatation of the areas characterized by a high salinization and reconstructs the geometry of the saline wedge front. In fact, the presence of seawater in the aquifers reduces subsurface resistivity values. In this study, five electrical profiles were performed using the Terrameter SAS4000 Lund Imaging System with an array of 64 electrodes. The Wenner configuration was used with a unit electrodes spacing of 5 m. Finally, we use hydrogeological data, and electrical resistivity tomography data superimposed with the location of wells to provide a conceptual framework for the understanding of the freshwater-saltwater interface in the Maâmoura region.

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Section: Methodsmentioning

confidence: 99%

Contribution of geophysics to geometric characterization of freshwater–saltwater interface in the Maâmoura region (NE Tunisia)

Chabaane

Redhaounia

Gabtni

et al. 2018

Euro-Mediterr J Environ Integr

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“…A Wenneralpha array with 10-m spacing between electrodes was constructed to collect the resistivity data, reaching an investigation depth of approximately 70 m. The electrical resistivity tomography data are presented in the form of inverted resistivity model including topography obtained using Res2DINV Software. The inversion algorithm is based on the standard smoothness-constrained least-squares inversion algorithm (Gauss-Newton method) (De Groot-Hedlin and Constable, 1990;Sasaki, 1992). For all models, the root mean square (RMS) error of the inversion in the resistivity model is less than 5%, which is well acceptable and the models are tolerable (ABEM, 2010)…”

Section: Electrical Resistivity Tomography (Ert)mentioning

confidence: 99%

Geophysical and hydrogeological investigations of water leakage from a reservoir dam to a coastal aquifer: the Lebna Case Study (Northeastern Tunisia)

et al. 2022

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In semiarid regions, dams are useful for surface water storage, sediment sequestration, and aquifer recharge. Built in 1987 on the Cap Bon peninsula (in northeastern Tunisia), the Lebna Dam is considered a good example of a multifunctional reservoir. The dam feeds two important irrigation networks, stores large sediment quantities, and allows a significant recharge flow to the underlying aquifer. This work suggests new leakage flow and dam-aquifer interaction characterizations through the development of an approach that combines a water balance calculation, geological field observations, groundwater monitoring, and geophysical research.The hydrological balance calculation performed over the monitoring period ,shows that an estimated water volume of 3.7 Mm 3 y -1 has leaked from the Lebna reservoir to the coastal aquifer. Geological mapping of the Lebna Dam basin in summer 2019 revealed the existence of permeable layers of sands to sandstones exposed along the southern banks of the reservoir and extending to an elevation that included the water level when the dam is full; these rocks outcrop at approximately 16 m.a.s.l.A geophysical survey based on 67 vertical electrical soundings and 8 electrical resistivity tomography profiles in the area downstream of the reservoir was carried out to identify the lateral continuity of the recharge zones. Piezometric campaigns consisting of four field surveys in 2019 and 2020 were conducted in the region downstream of Lebna Dam, consisting of 71 water well samples.The collected evidence led to the conclusion that concentrated recharge occurs in the downstream bank of the dam.

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“…The genus Johnius, type species, Johnius carutta Bloch, 1793, designated by Gill (1862, has been widely applied to several sciaenid fishes of the Indo-West Pacific. Trewavas (1977) reviewed the nomenclature and synonyms of genus Johnius; Sasaki (1989) defined the genus and the tribe Johniini by several synapomorphic characters: i) a hammer-shaped gas bladder with 13-17 arborescent lateral Most species of the genus Johnius have a restricted or limited distributions in the Indian and Pacific Oceans (e.g., Trewavas 1977;Lal Mohan 1975;Sasaki 1992Sasaki , 1999. However, several species of Johnius are widely distributed in the Indo-West Pacific (e.g., J. amblycephalus, J. belangerii, and J. borneensis).…”

Section: Introductionmentioning

confidence: 99%

“…(Johnius) species, leading to uncertainity and misidentifications in many publications (Trewavas 1977;Randall & Lim 2000;Sasaki 2001). Moreover, identifications become more complex when species in adjacent region are taken into account (J. trewavasae Sasaki, 1992;J. taiwanensis Chao et al, 2019); synonymized are names frequently applied (J. sina (Cuvier, 1830); J. tingi (Tang, 1937)); and similar diagnostic characters (J. carouna, J. heterolepis, and J. macrorhynus) are considered when defining the species.…”

Section: Introductionmentioning

confidence: 99%

Johnius sasakii, a new species of croaker (Perciformes: Sciaenidae) with a key to Johnius from East Malaysia, Borneo

Hanafi

Chen

Seah

et al. 2022

Zootaxa

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A new sciaenid fish, Johnius sasakii sp. nov. from the East Malaysian coastal waters of Sabah and Sarawak, Borneo is described herein. Johnius sasakii sp. nov. can be separated from the close congeners, Johnius heterolepis and Johnius carouna by having less gill rakers on the lower limb of the first gill arch (mode number 9 vs. 10 for J. heterolepis; 11 for J. carouna). It can be distinguished from J. heterolepis with the higher modal number of gill rakers on the upper limb of first gill arch (5 vs. 4), shorter anal-fin base length (9% vs. 10% of SL) and first anal-fin ray length (10–12% vs. 12–13% of SL) respectively. Furthermore, J. sasakii sp. nov. can be further differentiated from J. carouna by its shorter second anal-fin spine length 7–10% SL (usually 8–10%) vs. 11–14% SL (usually 11–12%) and slightly deeper body depth 25–29% SL (usually 26–28%) vs. 23–28% SL (usually 24–26%). Meanwhile, J. sasakii sp. nov. can be easily differentiated from J. macrorhynus by a present of molariform teeth on inner rows of jaws and stumpy gill rakers. Johnius (Johnius) sasakii sp. nov. can be clearly distinguished from species of the subgenus J. (Johnieops) by the lack of enlarged outer row teeth on upper jaw. A Kimura 2-parameter genetic distance comparison of 450 bp sequences of mitochondrial 16S rRNA and 488 bp nuclear gene S7 showed that J. sasakii sp. nov. are highly differentiated from J. heterolepis (16S: 10.4%, S7: 5.8%), J. carouna (16S:19.3%, S7:8.4%); and J. macrorhynus (16S: 16.7%, S7: 8.1%) respectively. The study highlights that the genetic approach from mtDNA and nDNA can contribute to the confirmation of taxonomic status of sympatric species in genus Johnius.

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Two new and two resurrected species of the sciaenid genusJohnius (Johnius) from the West Pacific

Cited by 9 publications

References 7 publications

Contribution of geophysics to geometric characterization of freshwater–saltwater interface in the Maâmoura region (NE Tunisia)

Contribution of geophysics to geometric characterization of freshwater–saltwater interface in the Maâmoura region (NE Tunisia)

Geophysical and hydrogeological investigations of water leakage from a reservoir dam to a coastal aquifer: the Lebna Case Study (Northeastern Tunisia)

Johnius sasakii, a new species of croaker (Perciformes: Sciaenidae) with a key to Johnius from East Malaysia, Borneo

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