Possible link between the structure of otoliths and amphibious mode of life of three mudskipper species (Teleostei: Gobioidei) from the Persian Gulf

The otoliths of three mudskipper species from the Persian Gulf that are characterised by different degrees of amphibious adaptation were examined using SEM imaging and otolith morphometry. <i>Scartelaos tenuis</i>, which is the most aquatic of the three species, has rhomboid to rectangular otoliths that conform to the general otolith type of many marine gobiid species. The otoliths of <i>Periophthalmus waltoni</i>, which is one of the most amphibious mudskipper species, are pentagonal-shaped and deviate from the usual otolith type of the Gobiidae by the absence of a posterodorsal projection and deep ostial lobes. <i>Boleophthalmus dussumieri</i> is intermediate with respect to its amphibious adaptation between <i>S. tenuis</i> and <i>P. waltoni</i>, and the shape of its otoliths is intermediate between the otoliths of those two species. Otolith morphometry related to sulcus measurements more clearly separated <i>P. waltoni</i> from <i>B. dussumieri</i>, than <i>S. tenuis</i> from either <i>P. waltoni</i> or <i>B. dussumieri</i>. As <i>P. waltoni</i> and <i>B. dussumieri</i> can occur syntopically and display similar behaviours, the morphometric disparity of their sulcus proportions might be related to efficient intraspecific communication among neighbouring species.

本研究采用扫描电子显微镜（SEM）成像与耳石形态测量分析方法，对波斯湾三种水陆适应程度各异的弹涂鱼物种的耳石开展了观察与测量。其中水生适应性最强的*Scartelaos tenuis*，其耳石呈菱形至矩形，符合多数海生鰕虎鱼的典型耳石形态特征。*Periophthalmus waltoni*是水陆适应性最强的弹涂鱼物种之一，其耳石呈五边形，因缺失后背侧突起与深口窝叶，与鰕虎科的典型耳石形态存在显著差异。*Boleophthalmus dussumieri*的水陆适应性介于*S. tenuis*与*P. waltoni*之间，其耳石形态也处于二者之间。相较于*S. tenuis*分别与*P. waltoni*或*B. dussumieri*的组间对比，基于耳石沟域测量的形态学参数能更清晰地将*P. waltoni*与*B. dussumieri*区分开来。鉴于*P. waltoni*与*B. dussumieri*可同域分布且行为习性相近，二者耳石沟域比例的形态学差异，可能与相邻物种间高效的种内通讯存在关联。