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スリランカのエラスモウミウシ動物群の同定に新たな知見を得た
New insights into the identities of the elasmobranch fauna of Sri Lanka.
PMID: 31716166 DOI: 10.11646/zootaxa.4585.2.1.
抄録
2018年3月に北西部、北部、東部の各州11カ所の魚市場と水揚げ場を対象に9日間の集中調査を実施した際に遭遇したスリランカ産のエラスモウミウシの身元を調査した。合計で34種のエラスモウミウシを代表する111の標本を調査した。全標本についてNADH2遺伝子の配列データを作成した。また、特定の同定を確認するために、25種のエラスモウミウシのサブグループについて、近縁種のデータを含む独立隣接結合分析を行った。34種のうち5種は新種である可能性が高い。これらの34種は、バトイド属のBrevitrygon、Narcine、Torpedo、セラキア属のCentrophorus、Chiloscylliumの各1種である。そのうち4種（Gymnura cf. poecilura 2、Carcharhinus cf. limbatus、Echinorhinus sp. 1、Iago cf. omanensis 1）は他の地域から以前に報告された未記載種と思われるものである。また，スリランカからは3種(Maculabatis arabica, Acroteriobatus variegatus, Centroscymnus owstonii)が初めて報告された。新種のPlanonasus indicusについて最近報告された2つの標本のうちの1つが今回の調査で採集されたものである。スリランカで確認された種の中にはインドでも発見されているものもあるが、これまでペルシャ湾やオマーン湾、東南アジアの地域でしか知られていなかったものもある。このような短期間の調査の結果、多くの新種が発見されたことは、30年近くの間、このような調査を妨げてきた内戦が終わった今、この地域でより集中的な調査を行うことの重要性を強調している。
Identities of elasmobranchs from Sri Lanka encountered during collections conducted in an intensive nine-day survey of fish markets and landing sites at 11 localities in the North Western, Northern, and Eastern Provinces in March of 2018 were assessed. In total, 111 specimens representing 34 elasmobranch species were examined. Sequence data for the NADH2 gene were generated for all specimens. Independent Neighbor-Joining analyses, which included data for related taxa, were conducted for 25 subgroups of elasmobranchs to help confirm specific identifications. Five of the 34 species encountered are likely new to science. These consist of one species each of the batoid genera Brevitrygon, Narcine, and Torpedo, and the selachian genera Centrophorus, and Chiloscyllium. The specific identities of 12 species previously known to occur in Sri Lanka are updated to conform to current taxonomy; four of these (Gymnura cf. poecilura 2, Carcharhinus cf. limbatus, Echinorhinus sp. 1, and Iago cf. omanensis 1) represent what appear to be undescribed species reported previously from other localities. Three species (Maculabatis arabica, Acroteriobatus variegatus, and Centroscymnus owstonii) are reported from Sri Lanka for the first time; the latter species also represents the first documented record of this genus and family for the island nation. One of the two specimens on which the recent description of the new species of Planonasus indicus was based was also collected as part of this survey. Although some of the species confirmed to occur in Sri Lanka have also been found in India, others were previously known only from the Persian Gulf, Gulf of Oman, or localities in Southeast Asia. The high amount of novelty discovered as a result of a survey of such short duration emphasizes the importance of more intensive survey efforts in this region now that the civil unrest that precluded such work for nearly three decades has come to an end.