Vol. 57, 2018

(update: 2018.07.18; 08.31) 

Swimbladder Evolution of Longfin Herrings (Pristigasteridae, Teleostei)

Sébastien Lavoué^1,5,*, Sahat Ratmuangkhwang², Hsuan-Ching Ho³, Wei-Jen Chen¹, and Mohd Nor Siti Azizah⁴

¹Institute of Oceanography, National Taiwan University, Roosevelt Road, Taipei 10617, Taiwan
²Andaman Coastal Research Station for Development, Faculty of Fisheries, Kasetsart University, Suksamran, Ranong 85120, Thailand
³National Museum of Marine Biology and Aquarium, Pingtung 944, Taiwan
⁴Institute of Marine Biotechnology, Universiti Malaysia Terengganu, Kuala Nerus 21030, Malaysia
⁵Open Researcher and Contributor, ID: 0000-0003-4798-6666

(Received 20 April 2018; Accepted 2 July 2018; Communicated by Hin-Kiu Mok)

Sébastien Lavoué, Sahat Ratmuangkhwang, Hsuan-Ching Ho, Wei-Jen Chen, and Mohd Nor Siti Azizah (2018) Longfin herrings form a monophyletic, circumtropically distributed family of mostly marine teleost fishes, the Pristigasteridae (Clupeoidei), that includes 38 species classified into nine genera and three main lineages (the Pelloninae, Pristigasterinae, and the genus Ilisha). The external morphology and osteology of the Pristigasteridae provide only a few, sometimes conflicting, informative characters which makes it difficult to reconstruct their phylogeny, but their swimbladder (a visceral gas-filled chamber that has several important functions in the Teleostei) appears to be highly specialized and variable among species. In particular, the swimbladder of most Indo-West Pacific pristigasterid species exhibits one or paired post-coelomic extensions, whereas New World species do not. The presence of these extensions conflicts with the current systematic classification, as they are only found in subsets of different taxa. To examine this conflict, the most comprehensive molecular phylogenetic tree of the Pristigasteridae to date was built using six molecular markers and 21 species. This tree deeply disagreed with the current classification in that it indicated that the subfamilies Pelloninae and Pristigasterinae are not monophyletic and neither are the genera Ilisha, Pellona, and Opisthopterus. Using this tree to infer the evolution of the post-coelomic extensions, it was found that their absence is the ancestral condition in the Pristigasteridae. Indo-West Pacific species with post-coelomic extensions evolved later and form a monophyletic group, inside which species with only one extension form a monophyletic group. The consequences of our findings on the evolution and classification of Pristigasteridae are discussed. We suggest that only species of Pristigasteridae having one or paired post-coelomic extensions should be included in the genus Ilisha.

Key words: Evolution, Phylogeny, Morphology, Molecules, Fish.

*Correspondence: Tel: +886 (02) 2363 6040 ext. 408. E-mail: microceb@hotmail.com

Supplementary Materials: Appendix 1