Some Differences in Subspecies Morphology of Zanclorhynchus spinifer (Pisces: Zanclorhynchidae)

Authors: Zhukov MYu

DOI: 10.23880/izab-16000339

Volume 4, Issue 6

Abstract

Additional data, calculation and statistics results of diagnostic parameters of the four subspecies of Zanclorhynchus spinifer Günther, 1880 are presented. Living for a long time in mostly geographically isolated populations within Antarctic Circumpolar Current (Marion-Crozet district, Kerguelen-Heard district, Macquarie Island, and Ridge of Hercules) leads to radiation into subspecies with significant morphological differences. The diagnostic importance of body depth, antedorsal distance, depth of gill opening, position of paired fins, proportions of the gill opening, heights of dorsal fin spines, and index of arming is confirmed. Of the 66 calculated pairs of parameters, 47 of them belongs to a different sets with statistical significance p<0.05. Antarctic horsefish differs from geographically closest Armed horsefish in maximum body depth, body depth at the origin of the anal fin, antedorsal distance, and index of arming with p-values lower than 0.000001. The index of arming also differentiates with p<0.001 Antarctic horsefish and Macquarian horsefish, Hercules horsefish and Armed horsefish, Macquarian horsefish and Armed horsefish. The difference in the sum of the lengths (heights) of the second, the third, and the fourth spines of first dorsal fin between all subspecies have statistical significance p<0.012. Differences in longitudinal orbit diameter have p-value <0.0001 in pairs Antarctic horsefish and Armed horsefish, Antarctic horsefish and Hercules horsefish. Listed parameters are sufficient for the identification of taxa.

Keywords: Southern Ocean; Antarctic Horsefish; Armed Horsefish; Macquarian Horsefish; Hercules Horsefish

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