Scholarlink

Background <p>Adult <i>Metarhadinorhynchus indicus</i> (Bhattacharya &amp; Banerjee, 2003) Kita, Nitta, Kajihara, 2024 were originally described from <i>Megalaspis cordyla</i> (Linn.) in the Chennai coast, Tamil Nadu, India as <i>Gorgorhynchoides indicus</i> Bhattacharya &amp; Banerjee, 2003. The genus <i>Gorgorhynchoides</i> Cable and Linderoth, 1963 was later synonymized with the genus <i>Metarhadinorhynchus</i> Yamaguti 1959.</p> Results <p>We accept the synonymies involving 15 species of <i>Gorgorhynchoides</i> transferred to <i>Metarhadinorhynchus.</i> Our recognition of the synonymies is partially resolved with the erection of two subgenera: <i>Metarhadinorhynchus</i> (<i>Metarhadinorhynchus</i>) subgen. nov. with 12 species and <i>Metarhadinorhynchus</i> (<i>Cylindratus</i>) subgenus nov. with 3 species based on the presence or absence of anterior trunk swelling, respectively. We have recently collected cystacanths of <i>M. indicus</i> from the Asia seabass, <i>Lates calarifer</i> (Barramundi) off Andaman &amp; Nicobar Islands, India. The cystacanths were comparable to the adults in the morphology of the common non-reproductive structures such as proboscis hooks and trunk spines with some variations mostly because of inaccuracies of descriptive statements in the original description. Comparisons are tabulated. Trunk size and reproductive structures varied because of their underdevelopment in the cystacanth stage. The anterior trunk swelling was sufficiently evident to confirm its presence in all stages of <i>M. indicus</i>. The long multinucleated filiform coiling lemnisci were similarly observed and the female genital pore is decidedly dorso-subterminal and not on the ventral side. A tabulated morphological description of the cystacanths and adults jointly constitute the redescription of <i>M. indicus</i>. The molecular characterization of the nuclear gene (18&#xa0;S) and the mitochondrial cytochrome <i>c</i> oxidase subunit 1 (<i>cox</i>1) sequence data of <i>Metarhadinorhynchus</i> (<i>Metarhadinorhynchus</i>) <i>indicus</i> is provided for the first time. Sequences from both genes were aligned and compared with other acanthocephalan species available in GenBank.</p> Conclusions <p>The phylogenetic analyses supported the establishment of the current species under the genus <i>Metarhadinorhynchus</i> Yamaguti, 1959. Additionally, in order to elucidate the phylogenetic relationships of the genus <i>Metarhadinorhynchus</i>, phylogenetic analyses were performed integrating different gene (18&#xa0;S + <i>cox</i>1) sequence data using maximum likelihood (ML) and Bayesian inference (BI). Our data supplement the molecular data for species description in the most reliable taxonomic frameworks alongside traditional morphological analysis.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

The erection of two subgenera for Metarhadinorhynchus Yamaguti, 1959 (Acanthocephala: Isthmosacanthida) with a redescription of Metarhadinorhynchus (Metarhadinorhynchus) indicus in India

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年7月11日

查看全文
  • Omar M. Amin,
  • Anshu Chaudhary,
  • Nataliya Rubtsova,
  • Bindu Sharma

摘要

Background

Adult Metarhadinorhynchus indicus (Bhattacharya & Banerjee, 2003) Kita, Nitta, Kajihara, 2024 were originally described from Megalaspis cordyla (Linn.) in the Chennai coast, Tamil Nadu, India as Gorgorhynchoides indicus Bhattacharya & Banerjee, 2003. The genus Gorgorhynchoides Cable and Linderoth, 1963 was later synonymized with the genus Metarhadinorhynchus Yamaguti 1959.

Results

We accept the synonymies involving 15 species of Gorgorhynchoides transferred to Metarhadinorhynchus. Our recognition of the synonymies is partially resolved with the erection of two subgenera: Metarhadinorhynchus (Metarhadinorhynchus) subgen. nov. with 12 species and Metarhadinorhynchus (Cylindratus) subgenus nov. with 3 species based on the presence or absence of anterior trunk swelling, respectively. We have recently collected cystacanths of M. indicus from the Asia seabass, Lates calarifer (Barramundi) off Andaman & Nicobar Islands, India. The cystacanths were comparable to the adults in the morphology of the common non-reproductive structures such as proboscis hooks and trunk spines with some variations mostly because of inaccuracies of descriptive statements in the original description. Comparisons are tabulated. Trunk size and reproductive structures varied because of their underdevelopment in the cystacanth stage. The anterior trunk swelling was sufficiently evident to confirm its presence in all stages of M. indicus. The long multinucleated filiform coiling lemnisci were similarly observed and the female genital pore is decidedly dorso-subterminal and not on the ventral side. A tabulated morphological description of the cystacanths and adults jointly constitute the redescription of M. indicus. The molecular characterization of the nuclear gene (18 S) and the mitochondrial cytochrome c oxidase subunit 1 (cox1) sequence data of Metarhadinorhynchus (Metarhadinorhynchus) indicus is provided for the first time. Sequences from both genes were aligned and compared with other acanthocephalan species available in GenBank.

Conclusions

The phylogenetic analyses supported the establishment of the current species under the genus Metarhadinorhynchus Yamaguti, 1959. Additionally, in order to elucidate the phylogenetic relationships of the genus Metarhadinorhynchus, phylogenetic analyses were performed integrating different gene (18 S + cox1) sequence data using maximum likelihood (ML) and Bayesian inference (BI). Our data supplement the molecular data for species description in the most reliable taxonomic frameworks alongside traditional morphological analysis.