930 research outputs found

    Examining evolutionary relationships and shifts in depth preferences in batfishes (Lophiiformes: Ogcocephalidae)

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    © 2014 Elsevier Inc. Batfishes (Ogcocephalidae) are an understudied, group of marine anglerfishes that are dorsoventrally flattened and have an illicium and esca (terminal lure) used to attract prey. The family contains 10 genera and 75 recognized species from nearly all tropical and subtropical seas. Relationships among these taxa, as well as the position of Ogcocephalidae within Lophiiformes, remain poorly understood with previous studies showing conflicting, and poorly resolved results. The timing of divergence and depth of origination in the water column have also not been explored in any detail. In this study a concatenated nuclear (three genes) and mitochondrial (two genes) dataset was constructed across several anglerfish families to elucidate phylogenetic relationships among all ten batfish genera, to clarify the placement of Ogcocephaloidei within Lophiiformes, and to estimate divergence times using fossil calibrations. An ancestral state reconstruction was also conducted to examine the history of shifts in preferred habitat depths within batfishes. Phylogenetic analyses supported monophyly of each sub-order within Lophiiformes and placed Ogcocephaloidei as the sister group to Antennarioidei. Batfish genera were divided into an Eastern Pacific/Western Atlantic clade and an Indo-Pacific clade; Halieutaea was recovered as the sister group to all other batfishes. Based on divergence time estimations and ancestral state reconstructions of preferred depth, Ogcocephalidae is Eocene in age and originated on the lower continental shelf/upper continental slope (disphotic zone)

    Adult morphology and redescription of Lestidiops indopacificus (Ege, 1953), with comments on the features of related species (Teleostei, Aulopiformes, Paralepididae)

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    Two specimens representing the first known adults of Lestidiops indopacificus (Ege, 1953) are reported and described from Taiwan, and the validity and generic assignment of this species are confirmed. The origin of the pelvic fin directly below the dorsal-fin base shows that L. indopacificus belongs to the L. mirabilis species complex. It can be separated from its congeners by the position of the nostrils above the posterior end of the maxilla, the light body color with unevenly distributed melanophores in adults, and a distinct combination of meristic values and other morphological characteristics. New geographic records are reported for the two other current members of this species complex, L. mirabilis (Ege, 1933) and L. extremus (Ege, 1953). The diagnostic features that separate these three very similar species are discussed

    First records of Hilsa kelee (Cuvier, 1829), Kelee Shad (Clupeiformes, Dorosomatidae), from the main island of Taiwan, South China Sea

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    Hilsa kelee (Cuvier, 1829) is widely distributed in the Indo-West Pacific, but so far it has been recorded only from insular areas (Matsu, Kinmen, and Penghu Islands) in Taiwanese waters. Here we report on 18 specimens collected from off Ke-tzu-liao, Kaohsiung City, southwestern main island of Taiwan. Morphometric and meristic data and an anatomical description of those specimens are presented, together with remarks on the distribution of the species and its occurrence in Taiwanese and adjacent waters

    New records of two cusk eels of the genus Neobythites from Taiwan, with a northward range extension of N. australiensis Nielsen, 2002 (Actinopterygii: Ophidiiformes: Ophidiidae)

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    Two species of cusk eels, Neobythites australiensis Nielsen, 2002 and Neobythites japonicus Uiblein et Nielsen, 2023 were collected from southwestern and northeastern Taiwan, respectively. They represent the first record of both species from Taiwan. The former specimen represents the first record from the Northern Hemisphere, and the latter specimen represents the second record of N. japonicus. As a result, eight species of Neobythites are recognized in Taiwan. We provide a detailed description of the two specimens, comparison with other available specimens, discussion of intraspecific variations, and a dichotomous key to species of Neobythites in Taiwan

    A new record of congrid eel, Bathycongrus bleekeri (Congridae) from Vietnam

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    Three specimens of Bathycongrus bleekeri were collected during the survey in 2015 and 2017. The newly recorded species is described herein, a small, moderately elongate species of Bathycongrus with head and body compressed; vertical fins without black mark; tail slender, attenuated, but not filiform; trunk length 1.2 times greater than head length; teeth small, conical, in about three-four rows on jaws, in a small triangular patch on vomer; 28–29 preanal vertebrae, total of 111–113 vertebrae; 26–28 preanal lateral-line pores. Additional data on the morphology and distribution of the species increases the total number of known species in the family Congridae in Vietnamese waters to twelve

    Evolutionary history of anglerfishes (Teleostei: Lophiiformes): a mitogenomic perspective

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    <p>Abstract</p> <p>Background</p> <p>The teleost order Lophiiformes, commonly known as the anglerfishes, contains a diverse array of marine fishes, ranging from benthic shallow-water dwellers to highly modified deep-sea midwater species. They comprise 321 living species placed in 68 genera, 18 families and 5 suborders, but approximately half of the species diversity is occupied by deep-sea ceratioids distributed among 11 families. The evolutionary origins of such remarkable habitat and species diversity, however, remain elusive because of the lack of fresh material for a majority of the deep-sea ceratioids and incompleteness of the fossil record across all of the Lophiiformes. To obtain a comprehensive picture of the phylogeny and evolutionary history of the anglerfishes, we assembled whole mitochondrial genome (mitogenome) sequences from 39 lophiiforms (33 newly determined during this study) representing all five suborders and 17 of the 18 families. Sequences of 77 higher teleosts including the 39 lophiiform sequences were unambiguously aligned and subjected to phylogenetic analysis and divergence time estimation.</p> <p>Results</p> <p>Partitioned maximum likelihood analysis confidently recovered monophyly for all of the higher taxa (including the order itself) with the exception of the Thaumatichthyidae (<it>Lasiognathus </it>was deeply nested within the Oneirodidae). The mitogenomic trees strongly support the most basal and an apical position of the Lophioidei and a clade comprising Chaunacoidei + Ceratioidei, respectively, although alternative phylogenetic positions of the remaining two suborders (Antennarioidei and Ogcocephaloidei) with respect to the above two lineages are statistically indistinguishable. While morphology-based intra-subordinal relationships for relatively shallow, benthic dwellers (Lophioidei, Antennarioidei, Ogcocephaloidei, Chaunacoidei) are either congruent with or statistically indistinguishable from the present mitogenomic tree, those of the principally deep-sea midwater dwellers (Ceratioidei) cannot be reconciled with the molecular phylogeny. A relaxed molecular-clock Bayesian analysis of the divergence times suggests that all of the subordinal diversifications have occurred during a relatively short time period between 100 and 130 Myr ago (early to mid Cretaceous).</p> <p>Conclusions</p> <p>The mitogenomic analyses revealed previously unappreciated phylogenetic relationships among the lophiiform suborders and ceratioid familes. Although the latter relationships cannot be reconciled with the earlier hypotheses based on morphology, we found that simple exclusion of the reductive or simplified characters can alleviate some of the conflict. The acquisition of novel features, such as male dwarfism, bioluminescent lures, and unique reproductive modes allowed the deep-sea ceratioids to diversify rapidly in a largely unexploited, food-poor bathypelagic zone (200-2000 m depth) relative to the other lophiiforms occurring in shallow coastal areas.</p

    Adjuvant chemotherapy and survival outcomes in rectal cancer patients with good response (ypT0-2N0) after neoadjuvant chemoradiotherapy and surgery: A retrospective nationwide analysis

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    BackgroundFor rectal cancer, it remains unclear how to incorporate tumor response to neoadjuvant chemoradiotherapy (nCRT) when deciding whether to give adjuvant chemotherapy. In this study, we aim to determinate the survival benefit of adjuvant chemotherapy for rectal cancer patients with good response (ypT0-2N0) after nCRT and surgery.MethodsThe study cohort included 720 rectal cancer patients who had good response (ypT0-2N0) after nCRT and surgery, who did or did not receive adjuvant chemotherapy between January 2007 and December 2017, from the Taiwan Cancer Registry and National Health Insurance Research database. The Kaplan–Meier method, log-rank tests, and Cox regression analysis were performed to investigate the effect of adjuvant chemotherapy on 5-year overall survival (OS) and disease-free survival (DFS).ResultsOf 720 patients, 368 (51.1%) received adjuvant chemotherapy and 352 (48.9%) did not. Patients who received adjuvant chemotherapy were more likely to be female, younger (≤ 65), with advanced clinical T (3-4)/N (1-2) classification and ypT2 classification. No significant difference in 5-year OS (p=0.681) or DFS (p=0.942) were observed by receipt of adjuvant chemotherapy or not. Multivariable analysis revealed adjuvant chemotherapy was not associated with better OS (adjusted hazard ratio [aHR], 1.03; 95% Confidence Interval [CI], 0.88-1.21) or DFS (aHR, 1.05; 95% CI, 0.89-1.24). Stratified analysis for OS and DFS found no significant protective effect in the use of adjuvant chemotherapy, even for those with advanced clinical T or N classification.ConclusionAdjuvant chemotherapy may be omitted in rectal cancer patients with good response (ypT0-2N0) after nCRT and surgery

    Malignant transformation in 5071 southern Taiwanese patients with potentially malignant oral mucosal disorders

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    BACKGROUND: Oral cancers can be preceded by clinically evident oral potentially malignant disorders (OPMDs). The current study evaluated the rate and the time of malignant transformation in the various OPMDs in a cohort of patients from southern Taiwan. Parameters possibly indicative for malignant transformation of OPMDs, such as epidemiological and etiological factors, and clinical and histopathological features were also described. METHODS: We followed-up 5071 patients with OPMDs—epithelial dysplasia with oral submucous fibrosis, epithelial dysplasia with hyperkeratosis/epithelial hyperplasia, hyperkeratosis/epithelial hyperplasia, oral submucous fibrosis, lichen planus, and verrucous hyperplasia—between 2001 and 2010 for malignant transformation. RESULTS: Two hundred nineteen of these 5071 OPMD patients (202 men, 17 women; mean age: 51.25 years; range: 30–81 years) developed oral cancers (179 squamous cell carcinomas; 40 verrucous carcinomas) in the same sites as the initial lesions at least 6 months after their initial biopsies. The overall transformation rate was 4.32% (mean duration of transformation: 33.56 months; range: 6–67 months). Additionally, the mean time of malignant transformation was significantly shorter for lesions with than without epithelial dysplasia. The risk of malignant transformation was 1.89 times higher for epithelially dysplastic than non-dysplastic lesions. The anatomical site of OPMD and the presence of epithelial dysplasia were significantly associated with malignant transformation. The hazard rate ratio was 1.87 times larger for tongue lesions than for buccal lesions. CONCLUSION: Patients with OPMDs require long-term follow up
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