Morphology of the cephalothorax integument of Bryocamptus pygmaeus (Copepoda: Harpacticoida: Canthocamptidae), based on a new research method

A.A. Novikov & E.B. Fefilova

Abstract. The number and location of sensilla and pores of the cephalothorax integument of the species Bryocamptus pygmaeus (G.O. Sars, 1863) (Copepoda, Canthocamptidae) were studied for the first time on the material from several European regions: the southeastern part of the Bolshezemelskaya tundra (Nenets Autonomous District), the north of the Komi Republic, the Republic of Karelia, and the central part of European Russia (Udmurt Republic). In the samples examined, two groups of populations differing in the characters of cephalothorax integument were recognised. These differences were found to correlate with the variability of the endopod of fourth pair of female legs, which bears four setae in specimens of the eastern form, while a specimen examined from Karelia has five setae. Pore maps are composed for both groups of morphotypes. A statistical analysis was carried out based on a new technique using three-dimensional models of the cephalothorax. As a result of this analysis, a high similarity between individuals of the eastern form and differences of the latter from the Karelian specimen were revealed.

Key words: integumental organs, copepods, freshwater harpacticoids, variability, Canthocamptidae

Zoosystematica Rossica, 2021, 30(2): 320–330 ▪ Published online 13 December 2021

https://doi.org/10.31610/zsr/2021.30.2.320 ▪ Open full article

Electronic supplementary materials

Electronic supplementary material 1

Macro for a pixel-by-pixel spiral sweep of lightness in ImageJ software

Electronic supplementary material 2

Matrix of lightness values for each pixel on the maps of the probability of distribution of pores and sensilla in the examined individuals of Bryocamptus. The specimen codes are given in Table 1. Values range from 0 to 255.

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