47 research outputs found

    Nodosilinea signiensis sp. nov. (Leptolyngbyaceae, Synechococcales), a new terrestrial cyanobacterium isolated from mats collected on Signy Island, South Orkney Islands, Antarctica

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    Terrestrial cyanobacteria are very diverse and widely distributed in Antarctica, where they can form macroscopically visible biofilms on the surfaces of soils and rocks, and on benthic surfaces in fresh waters. We recently isolated several terrestrial cyanobacteria from soils collected on Signy Island, South Orkney Islands, Antarctica. Among them, we found a novel species of Nodosilinea, named here as Nodosilinea signiensis sp. nov. This new species is morphologically and genetically distinct from other described species. Morphological examination indicated that the new species is differentiated from others in the genus by cell size, cell shape, filament attenuation, sheath morphology and granulation. 16S rDNA phylogenetic analyses clearly confirmed that N. signiensis belongs to the genus Nodosilinea, but that it is genetically distinct from other known species of Nodosilinea. The D1–D1´ helix of the 16S–23S ITS region of the new species was also different from previously described Nodosilinea species. This is the first detailed characterization of a member of the genus Nodosilinea from Antarctica as well as being a newly described species

    Petrocephalus boboto and Petrocephalus arnegardi, two new species of African electric fish (Osteoglossomorpha, Mormyridae) from the Congo River basin

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    A specimen of the African weakly electric fish genus Petrocephalus (Osteoglossomorpha, Mormyridae) collected in the Congo River at Yangambi, Orientale Province, Democratic Republic of Congo, is described as a new species. Petrocephalus boboto sp. n. can be distinguished from other Central African species of Petrocephalus by a combination of the following characteristics: three distinct black spots on the body, one at the origin of the pectoral fin, one at the origin of the caudal fin and one below the anterior base of the dorsal fin; Nakenrosette and Khelrosette electroreceptor clusters distinct on head but Augenrosette cluster reduced in size; 23 branched dorsal rays, 34 branched anal rays, and electric organ discharge waveform triphasic. Petrocephalus boboto sp. n. most closely resembles the holotype of Petrocephalus binotatus but is easily distinguished from it by its smaller mouth. A comparative molecular analysis including 21 other Petrocephalus species shows Petrocephalus boboto sp. n. to be genetically distinctive and to represent a deep lineage in the genus. Two specimens of Petrocephalus collected at Yangambi are morphologically similar and genetically closely related to specimens previously assigned to Petrocephalus binotatus, collected in the northwestern Congo River basin within Odzala-Kokua National Park, Republic of the Congo. This prompts us to formally describe a new species from these collections, Petrocephalus arnegardi sp. n., that, although similar to the holotype of Petrocephalus binotatus, can be distinguished from it by its smaller mouth and shorter interorbital width

    Petrocephalus boboto and Petrocephalus arnegardi, two new species of African electric fish (Osteoglossomorpha, Mormyridae) from the Congo River basin

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    A specimen of the African weakly electric fish genus Petrocephalus (Osteoglossomorpha, Mormyridae) collected in the Congo River at Yangambi, Orientale Province, Democratic Republic of Congo, is described as a new species. Petrocephalus boboto sp. n. can be distinguished from other Central African species of Petrocephalus by a combination of the following characteristics: three distinct black spots on the body, one at the origin of the pectoral fin, one at the origin of the caudal fin and one below the anterior base of the dorsal fin; Nakenrosette and Khelrosette electroreceptor clusters distinct on head but Augenrosette cluster reduced in size; 23 branched dorsal rays, 34 branched anal rays, and electric organ discharge waveform triphasic. Petrocephalus boboto sp. n. most closely resembles the holotype of Petrocephalus binotatus but is easily distinguished from it by its smaller mouth. A comparative molecular analysis including 21 other Petrocephalus species shows Petrocephalus boboto sp. n. to be genetically distinctive and to represent a deep lineage in the genus. Two specimens of Petrocephalus collected at Yangambi are morphologically similar and genetically closely related to specimens previously assigned to Petrocephalus binotatus, collected in the northwestern Congo River basin within Odzala-Kokua National Park, Republic of the Congo. This prompts us to formally describe a new species from these collections, Petrocephalus arnegardi sp. n., that, although similar to the holotype of Petrocephalus binotatus, can be distinguished from it by its smaller mouth and shorter interorbital width

    Description of three new species previously identified as Stolephorus bengalensis (Dutt & Babu Rao, 1959) or Stolephorus insularis Hardenberg, 1933 and a re-description of S. bengalensis (Chordata, Osteichthyes, Clupeiformes, Engraulidae)

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    Examination of numerous specimens characterised by predorsal scute, long maxilla, indented preopercle and pelvic scute lacking a spine and previously identified as Stolephorus bengalensis (Dutt & Babu Rao, 1959) or Stolephorus insularis Hardenberg, 1933, revealed four distinct species, true S. bengalensis (distributed from the Bay of Bengal to Pakistan) and three new species, viz., Stolephorus eldorado sp. nov. (Taiwan to Java, Indonesia), Stolephorus diabolus sp. nov. (Strait of Malacca, from Penang , Malaysia, to Singapore) and Stolephorus eclipsis sp. nov. (Bintan Island, Riau Archipelago, Indonesia). Characters separating the four species include numbers of gill rakers on each gill arch and vertebrae and pelvic fin and dorsal-fin ray lengths. Two molecular markers (mitochondrial cytochrome b and cytochrome oxidase I genes) demonstrated the distinction of three of the species examined morphologically and enabled a reconstruction of their phylogenetic relationships. Each species was genetically divergent from the others by 3.5%–7.7% mean uncorrected distance in the mitochondrial cytochrome oxidase I gene

    Cryptomyrus: a new genus of Mormyridae (Teleostei, Osteoglossomorpha) with two new species from Gabon, West-Central Africa

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    We use mitochondrial and nuclear sequence data to show that three weakly electric mormyrid fish specimens collected at three widely separated localities in Gabon, Africa over a 13-year period represent an unrecognized lineage within the subfamily Mormyrinae and determine its phylogenetic position with respect to other taxa. We describe these three specimens as a new genus containing two new species. Cryptomyrus, new genus, is readily distinguished from all other mormyrid genera by a combination of features of squamation, morphometrics, and dental attributes. Cryptomyrus ogoouensis, new species, is differentiated from its single congener, Cryptomyrus ona, new species, by the possession of an anal-fin origin located well in advance of the dorsal fin, a narrow caudal peduncle and caudal-fin lobes nearly as long as the peduncle. In C. ona, the anal-fin origin is located only slightly in advance of the dorsal fin, the caudal peduncle is deep and the caudal-fin lobes considerably shorter than the peduncle. Continued discovery of new taxa within the “Lower Guinea Clade” of Mormyridae highlights the incompleteness of our knowledge of fish diversity in West-Central Africa. We present a revised key to the mormyrid genera of Lower Guinea

    Genetic evidence for the recognition of two allopatric species of Asian bronze featherback Notopterus (Teleostei, Osteoglossomorpha, Notopteridae)

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    The fish genus Notopterus Lacepède, 1800 (Notopteridae) currently includes only one species, the Asian bronze featherback Notopterus notopterus (Pallas, 1769). This common freshwater species is widely distributed in the Oriental region, from the Indus basin in the west, the Mekong basin in the east and Java Island in the south. To examine the phylogeographic structure of N. notopterus across its range, we analysed 74 publicly available cytochrome oxidase I (COI) sequences, 72 of them determined from known-origin specimens, along with four newly-determined sequences from Peninsular Malaysian specimens. We found that N. notopterus is a complex of two allopatric species that diverge from each other by 7.5% mean p-distance. The first species is endemic to South Asia (from Indus basin to Ganga-Brahmaputra system), whereas the distribution of the second species is restricted to Southeast Asia. The exact limit between the distributions of these two species is not known, but it should fall somewhere between the Ganga-Brahmaputra and Salween basins, a region already identified as a major faunal boundary in the Oriental region. The name N. notopterus is retained for the Southeast Asian species, while the name Notopterus synurus (Bloch & Schneider, 1801) should be applied to the South Asian species. A comparative morphological study is needed to reveal the degree of morphological differentiation between the two species

    Ichthyofauna of Sungai Merbok Mangrove Forest Reserve, northwest Peninsular Malaysia, and its adjacent marine waters

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    Sungai Merbok Mangrove Forest Reserve, encompassing the Merbok river estuary, was established as a permanent forest reserve in 1951 and is the second-largest intact mangrove forest patch in Peninsular Malaysia. Despite its importance, few studies have been conducted to assess its aquatic biodiversity. In this study, we surveyed the fish diversity of the Merbok river estuary, and its adjacent marine waters. We recorded 138 fish species belonging to two classes, 18 orders, 47 families, and 94 genera. The richest order is Perciformes, with 32 recorded species, represents 23% of the alpha diversity, followed by Carangiformes with 21 recorded species or 14% of the diversity. Low taxonomic diversity overlaps with previous inventories and indicates that the inventory is still incomplete. All specimens examined are catalogued and deposited in a local museum collection. The fish checklist presented here represents a step forward in the conservation of fish diversity in the Merbok river estuary
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