摘要
We have determined two cellular parameters (DNA contents, and cell sizes) of 23 species of batoids, including three torpedinoids, two rhinobatoids, five rajoids, and 13 myliobatoids by flow cytometry. The ranges of DNA content and cell volume indices are 4.91-24.07 picograms per cell (hereafter, pg/cell) and 0.2-1.4, respectively. Intergroup comparisons of rajoids and myliobatoids find them characterized by smaller variances of DNA content, 6.64 ± 0.63 and 10.22 ± 1.91 pg/cell, respectively, whereas torpedinoids possess the largest variance of DNA content, 17.64 ± 5.57 pg/cell, followed by rhinobatoids, 6.93 ± 2.86 pg/cell. Following the DNA content evolution model, we constructed a phylogenetic tree based on the intragroup DNA content variation. This phylogenetic tree is consistent with the tentative scheme for the phylogeny of batoids proposed according to morphological and anatomical data except for torpedinoids. To address whether genome size variation might condition cell volume, we analyzed the correlation between DNA contents and cell volumes of these 23 species and found no significant linear correlation (r = 0.39, n = 23, P > 0.25). This result suggests that batoid DNA content variation might not play a major role as a nucleoskeleton.