Morphometrics of eight Chinese cavefish species

Abstract

Chinese cavefishes are a bizarre and interesting vertebrate taxa, but one with relatively little research. China holds the highest global cavefish diversity, accounting for about one-third of known species. Sinocyclocheilus is the largest genus of cavefishes in the world and is endemic to the south of China. The distribution of Sinocyclocheilus species is very narrow, and sometimes they inhabit just a single cave; this feature increases the vulnerability to extinction. With this study we provide the first comprehensive dataset related to the morphometrics of eight Sinocyclocheilus species. In addition to enhancing our knowledge on these poorly known species we aim to provide a dataset useful for future comparative analyses aiming to better understand the adaptive ability of cavefishes.

Fig. 1

Map of the area from where the specimens were collected. Each symbol corresponds to a distinct population of the following species: Sinocyclocheilus brevibarbatus (blue), S. brevis (yellow), S. huanjiangensis (green), S. jii (violet), S. lateristritus (brown), S. mashanensis (red), S. microphthalmus (orange), S. qiubeiensis (pink). Maps were created with the program QGIS using data from http://www.ngcc.cn/ngcc//html/1/.

Fig. 2

Reference adopted in fishes’ body measurements. In the figure two individuals of (a) S. microphtalmus and (b) S. jii showing all the landmarks and dashed lines used to record measurements on (a) the lateral and (b) the ventral side of the fish body (see the main text for a detailed description of the recorded measurements). Shaded area indicates the fish humpback.

Fig. 3

Reference showing the different shapes of the considered cavefish organs. Eye: Developed, Reduced, Absent. Mouth: Terminal, Subterminal, Inferior, Superior. Caudal fin: Rounded, Truncate, Emarginate, Forked, Lunate. Images for mouth and caudal fin are modified from.