A Taxonomic Review of Lancelets (Cephalochordata) in Japanese Waters

Nishikawa, Teruaki

doi:10.1007/978-4-431-56432-4_27

Cited by 3 publications

(2 citation statements)

References 27 publications

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“…Despite the general importance of Branchiostomatidae, little is known about much of this family. Several species were newly described, or their taxonomy has been clarified only recently [2,29,30], and species misidentification or cryptic diversity have been found using molecular approaches or integrative taxonomy [14,[31][32][33][34][35][36]. Moreover, new records of lancelet larvae or adults improved our assessment of species-specific geographical distribution and ecological traits at a range of scales [37][38][39][40][41][42][43][44][45][46].…”

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confidence: 99%

Molecular taxonomy confirms that the northeastern Atlantic and Mediterranean Sea harbor a single lancelet, Branchiostoma lanceolatum (Pallas, 1774) (Cephalochordata: Leptocardii: Branchiostomatidae)

et al. 2021

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Branchiostomatidae (lancelets or amphioxus) comprises about 30 species, several of which are well-established models in evolutionary development. Our zoological and ecological knowledge of the family is nonetheless limited. Despite evident differences can be found among known populations, the taxonomy of Branchiostoma lanceolatum (type species of the genus Branchiostoma) has never been investigated with modern methods through its range in the northeastern Atlantic and Mediterranean Sea. We address this via a multilocus molecular approach and comparing specimens collected from different European populations. Results obtained here confirm the presence of a single species inhabiting the range between the topotypical localities of B. lanceolatum (Atlantic Ocean) and of its junior synonym B. lubricum (Mediterranean Sea), without evincing geographical structure between populations. This suggests that environment most likely drives the characteristics observed in different geographic areas. The long larval phase and the slow mutation rate in lancelets may have played a key role in the evolutionary history of this iconic species.

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Section: Introductionmentioning

confidence: 99%

Molecular taxonomy confirms that the northeastern Atlantic and Mediterranean Sea harbor a single lancelet, Branchiostoma lanceolatum (Pallas, 1774) (Cephalochordata: Leptocardii: Branchiostomatidae)

et al. 2021

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“…Lancelets are presently classified into three genera (Branchiostoma, Asymmetron and Epigonichythys) from both morphological and molecular perspectives, supported by Nishikawa (2004Nishikawa ( , 2017, Nohara et al (2005), Kon et al (2007), Li et al (2014), and Igawa et al (2017). The genus Branchiostoma has a longitudinal series of gonads on both sides of the body, whereas the other genera have gonads on the right side only.…”

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confidence: 99%

Reinstatement of the Lancelet Name Asymmetron lucayanum, Recently Proposed as a Junior Synonym of Branchiostoma pelagicum (Cephalochordata)

Nishikawa

2018

Spec.Div.

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A recent proposal to reduce the binomen Asymmetron lucayanum Andrews, 1893 to the synonymy of Brachiostoma pelagicum Günther, 1889 lacked supporting evidence, and is considered flawed due to the uncertain taxonomic status of the latter. Examination of the holotype of B. pelagicum was hindered by its highly deteriorated state, to the extent that gonad condition and hence generic affinity could not be unequivocally determined. However, the description of gonads on both sides of the body in the original description suggests correct placement of the species in Branchiostoma. Furthermore, a published figure of a likely syntype (pelagic larva) of A. lucayanum showed the specimen to possess an elongated urostyloid process, such being absent in the (pelagic) holotype of B. pelagicum comparable in size and morphology with the former. It is proposed that Asymmetron lucayanum Andrews, 1893 be reinstated as a valid species.

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A New Find of the Whale-fall Lancelet Asymmetron inferum (Cephalochordata) near a Hydrothermal Vent at Oomuro-dashi Submarine Volcano in the Izu Islands, Pacific Coast of Japan, as a Possible Case to Prove the Stepping-stone Hypothesis

et al. 2017

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Two mature specimens of the whale-fall lancelet Asymmetron inferum Nishikawa, 2004, were collected in 2016 from reducing gravel bottom near a hydrothermal vent, 196 m deep, at Oomuro Hole of Oomuro-dashi submarine volcano in the Izu Islands, Pacific coast of Japan by using the ROV Hyper-Dolphin during the RV Shinsei-maru KS-16-6 cruise of JAMSTEC. This species has so far been known exclusively from whale-fall communities off Cape Nomamisaki, SW Kyushu, Japan, 219-254 m deep. The new find suggests the dispersal stepping-stone hypothesis of whale-fall communities for the origin of vent and/or seep fauna.

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A Taxonomic Review of Lancelets (Cephalochordata) in Japanese Waters

Cited by 3 publications

References 27 publications

Molecular taxonomy confirms that the northeastern Atlantic and Mediterranean Sea harbor a single lancelet, Branchiostoma lanceolatum (Pallas, 1774) (Cephalochordata: Leptocardii: Branchiostomatidae)

Molecular taxonomy confirms that the northeastern Atlantic and Mediterranean Sea harbor a single lancelet, Branchiostoma lanceolatum (Pallas, 1774) (Cephalochordata: Leptocardii: Branchiostomatidae)

Reinstatement of the Lancelet Name <i>Asymmetron lucayanum</i>, Recently Proposed as a Junior Synonym of <i>Branchiostoma pelagicum</i> (Cephalochordata)

A New Find of the Whale-fall Lancelet <i>Asymmetron inferum</i> (Cephalochordata) near a Hydrothermal Vent at Oomuro-dashi Submarine Volcano in the Izu Islands, Pacific Coast of Japan, as a Possible Case to Prove the Stepping-stone Hypothesis

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