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Adult specimens of Osteobrama cotio sensu lato. A) NRM 68948, 58.6 mm SL. Bangladesh: Meghna River drainage, Kushiyara River at Fenchuganj. B) NRM 40578, 63.9 mm SL. India: Brahmaputra River drainage, Dibrugarh Market. C) NRM 67707, 74.4 mm SL, Bangladesh: Karnafuli river drainage, Kaptai Lake.
Source publication
Osteobrama cotio is considered to be a widespread species in India and Bangladesh. Mitochondrial DNA (COI, 16S rRNA) shows that populations from the Meghna River, Karnafuli and Sangu Rivers, Narmada River, and Godavari River are genetically distinct from each other. No morphological differences were found to separate Meghna and Karnafuli+Sangu popu...
Contexts in source publication
Context 1
... phylogram based on 16S rRNA sequences (Fig. 4) is similar to the COI tree ( Fig. 1), with two major clades reflecting clades A and B in the COI tree, but the number of sequences and distinct localities is smaller, with 14 sequences from the Barak River, two from the Meghna River, and one each from the Karnafuli and Sangu Rivers. Separation of Osteobrama cotio and "O. serrata" is not ...
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... specimens were available from the Narmada or Barak River drainages for a morphometric comparison. Ontogenetic shape change was noticeable, with young specimens more elongate than adults, but this transition was shared among samples (Figs 1-2). Fin-ray counts were taken from 10 specimens from the Meghna and 11 from the Karnafuli+Sangu drainages. ...
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... apparently refers to the pseudotympanum, which is not shown on Hamilton's figure. We have not observed the black spots in any specimens of O. cotio, and there is no mention of them in later literature describing O. cotio. Black spots as shown and described by Hamilton, however, are shown on photos of O cunma and O. cotio in Maisnam et al. (2018: fig. 1, b,c), and O. vigorsii in Jadhav et ...
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... et al. (2018: table 2) listed specimen catalog numbers MUMF 4501-14506 as "O. serrata", but the publication does not contain the explicit fixation of a holotype, or syntypes, and consequently the name is not available under the International Code of Zoological Nomenclature (International Commission on Zoological Nomenclature 1999: Articles16.4, 16.4.1, 72.3, 73.2, 73.21, 732.1.1). Actually, the number of specimens is uncertain. The number collected is stated to be four on p. 361, corresponding to the GenBank numbers in table 1, but table 2 has data for six specimens. Four sequences where submitted to GenBank both as O. cotio and as "O. serrata". Dhanze & Dhanze (2018) reported specimens identified as Osteobrama ...
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... dealing with COI variation in O. belangeri, O. cotio, and O. feae, but that paper contains no sample metadata, and the sequences were not published by GenBank or other publicly accessible nucleotide sequence repository. Osteobrama cunma is a relatively deep- bodied species, similar to O. cotio. The specimen figured by Dhanze & Dhanze (2018: fig. 18) as O. cunma, is strikingly slender in comparison with O. cunma of the same length from the Ayeyawaddy basin, suggesting a need for revision of Dhanze & Dhanze's (2018) ...
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... Osteobrama cotio, and compatibility with the original description, we conclude that "O. serrata" of Singh et al. (2018), and O. cotio of Vishwanath & Shantakumar (2007) and Maisnam et al. (21017), as well as most other records of O. cotio, represent O. cotio sensu Hamilton, i.e., in a strict sense. Based on our analysis of mtDNA sequences (Fig. 1), the populations in the Narmada, Godavari and Sangu+Karnafuli rivers apparently represent undescribed cryptic species or distinct populations. In the case of the Karnafuli+Sangu population, no morphological characters were found to differentiate it from O. cotio. We have not examined specimens from the Narmada or Godavari drainages, ...
Citations
... Species of Osteobrama are frequent and abundant in lentic habitats throughout their range in Bangladesh, India, Myanmar, and Pakistan (Hora & Misra 1940;Talwar &Jhingran 1991 andVishwanath &Shantakumar 2007). Rahman et al. (2018) recognized eight species of Osteobrama, viz., O. belangeri (Valenciennes 1844); O. feae Vinciguerra (1890) and O. cunma (Day 1888) from the Chindwin-Irrawaddy drainage of India and Myanmar; O. cotio (Hamilton 1822) from the Barak-Meghna and Ganga-Brahmaputra drainages of India and Bangladesh; O. neilli (Day 1873) from the Cauvery drainage of India; O. bakeri (Day 1873) from west-flowing rivers in Kerala; and O. vigorsii (Sykes 1839) and O. peninsularis Silas (1952) from the Godavari and Krishna drainages of India. Hora & Misra (1940) described Osteobrama dayi from the Godavari River based on three specimens. ...
A new species of the genus Osteobrama is described from the Mahanadi River, Tikarpada, Angul District, Odisha state, India. Osteobrama tikarpadaensis, new species, differs from its congeners in having two pairs of minute barbels; iii–iv unbranched dorsal-fin rays with 25–33 serrae on the last unbranched ray; 15–16 branched pectoral-fin rays, and 25–27 branched anal-fin rays. The status of Osteobrama dayi is discussed and shown to be a valid species. A key to the species of the genus is provided.
... OBUs 126, Osteobrama cotio, and 127, O. cf. cotio, differed in coi and mt-rnr2 sequences 22 . Samples from the Karnafuli and Sangu drainages were slightly different from those from the Meghna drainage, including published sequences from the Barak River. ...
... Samples from the Karnafuli and Sangu drainages were slightly different from those from the Meghna drainage, including published sequences from the Barak River. No morphological differences were found and they might be cryptic species 22 . Because O. cotio is a widespread species, it should be re-analyzed with inclusion of representation of the entire geographical distribution 23 . ...
... Consequently, "cryptic OBUs" require taxonomic assessment, and evolutionary analysis, and in the meantime remain ghost OBUs. Whereas many of our sequences cannot be linked to a particular species, only few cases of sibling or cryptic species were demonstrated in cyprinids and badids so far 18,20,22 , and the unidentified OBUs should not be assumed to represent cryptic species or undescribed species in the absence of taxonomic analysis. Nation-wide or regional barcoding surveys, have been proposed to accelerate DNA barcode coverage 43 , and some have been attempted, such as the one reported here. ...
We sequenced the standard DNA barcode gene fragment in 694 newly collected specimens, representing 243 species level Operational Barcode Units (OBUs) of freshwater fishes from Bangladesh. We produced coi sequences for 149 out of the 237 species already recorded from Bangladesh. Another 83 species sequenced were not previously recorded for the country, and include about 30 undescribed or potentially undescribed species. Several of the taxa that we could not sample represent erroneous records for the country, or sporadic occurrences. Species identifications were classified at confidence levels 1(best) to 3 (worst). We propose the new term Operational Barcode Unit (OBU) to simplify references to would-be DNA barcode sequences and sequence clusters. We found one case where there were two mitochondrial lineages present in the same species, several cases of cryptic species, one case of introgression, one species yielding a pseudogene to standard barcoding primers, and several cases of taxonomic uncertainty and need for taxonomic revision. Large scale national level DNA barcode prospecting in high diversity regions may suffer from lack of taxonomic expertise that cripples the result. Consequently, DNA barcoding should be performed in the context of taxonomic revision, and have a defined, competent end-user.
... It is unlikely that it represents an undetected species that has hybridized with B. pallidus in the Sangu River, but this hypothesis is open for testing. Observations of other species in southeastern Bangladesh show that the Sangu and Karnafuli Rivers share a distinct fish fauna (e.g., Rahman et al. 2018). Kullander et al. (2017) reported on introgression in Devario anomalus Conway, Mayden & Tang, 2009, a species restricted to the Sangu and Matamuhuri Rivers and coastal streams near Cox′s Bazar, by Devario aequipinnatus (M′Clelland,1839), a common species in the Karnafuli and more western drainages, but not recorded from the Sangu River. ...
Five species of Badidae are reported from Bangladesh, with morphological diagnoses and mitochondrial DNA sequences (cytochrome b, cytb; and cytochrome c oxidase subunit I, coi). Dario kajal is recorded from Bangladesh for the first time with a precise locality. Badis badis is reported from several localities in central Bangladesh. Badis chittagongis is redescribed on the basis of samples from the region of Cox′s Bazar, including Maheskhali Island. Badis pallidus, new species, is described from the Sangu and Karnafuli River drainages in Bangladesh. It is most similar to B. chittagongis, but differs slightly in colouration and meristics, and is separated by 3.8% uncorrected p-distance in coi from B. chittagongis. Badis chittagongis and B. pallidus are almost identical in morphology, colour pattern and meristics, but occupy different habitats and are reciprocally allopatric. Pronounced genetic difference but similar morphology in these two species may be due to strong stabilizing selection for cryptic colouration in Badis. Badis rhabdotus is a new species from northeastern Bangladesh and adjacent Meghalaya in India. It is distinguished from congeneric species by the colour pattern, including well-defined narrow vertical bars; posterior bars curved; and meristics. Species delimitation analysis of an alignment comprising all coi sequences available from GenBank longer than 600 bp and attributed to species of Badidae (21 June 2018) plus our coi sequences and outgroup sequences of Nandus nandus, using pairwise p-distance and the computer software GMYC, ABGD, and bPTP, produced similar results. Among 103 coi sequences of Badidae, unidentified or tagged with one of 18 valid species names, uncorrected p-distance suggests 27 OTUs at 2% difference threshold; ABGD found between 15 and 55 OTUs; GMYC with single evolutionary rate 33 OTUs, with multiple evolutionary rates 32 OTUs; PTP, mPTP and bPTP 27–28 OTUs. Phylogenetic analysis based on coi and cytb sequences support previous analyses and previously proposed species groups. Inadequate recent species descriptions and many misidentifications or provisional identifications of published DNA sequences hamper progress in species-level systematics in Badis. Based on published morphological data, Badis triocellus cannot be distinguished from B. singenensis; Badis dibruensis and B. pancharatnaensis cannot be distinguished from B. badis; Badis andrewraoi, B. autumnum, B. kyanos, and B. soraya are insufficiently well distinguished from each other.
