Zoological Studies

Microscopic Structure and Digital Morphometric Analysis of the Statoconia of Hagfish, Paramyxine nelsoni (Myxiniformes)

Yi-Hsin Lee, Hung-Tu Huang, and Hin-Kiu Mok (2007) The structure and parameters of the statoconia (including the size, shape, number, and setting) in the macula communis in glycol methacrylate sections of the ventromedial side of the labyrinth of the hagfish, Paramyxine nelsoni (Myxinidae), are reported. The objective of this study was to ascertain if a relationship exists between body length, a parameter relating to age, and traits of the statoconia. Variations in these parameters with body size were investigated. The number of statoconia increased with body length. Individual hagfish contained statoconia of various sizes ranging from 1 to 26 µm. Small statoconia were present even in adults that had already reached a maximum body size, while very large statoconia were found in smaller individuals. Statoconia have a clear core and a few concentrically arranged alternating dense and clear layers. Statoconia are extracellular concretions that probably originate from vacuolated epithelial cells in the macula communis, and large statoconia are the result of the fusion of smaller statoconia. We concluded that these parameters of the hagfish, s statoconia contain no information which may be useful in estimating hagfish age.