Department of Oceanography (Marine Biology group), National Sun Yat-sen University, Kaohsiung, Taiwan.
Department of Oceanography (Marine Biology group), National Sun Yat-sen University, Kaohsiung, Taiwan 2Marine Ecology and Conservation Research Center, National Academy of Marine Research, Kaohsiung, Taiwan. Institute of Marine Ecology and Conservation, National Sun Yat-sen University, Kaohsiung, Taiwan .
Zootaxa. 2022 Mar 21;5116(3):393-409. doi: 10.11646/zootaxa.5116.3.5.
A new sciaenid fish, Johnius sasakii sp. nov. from the East Malaysian coastal waters of Sabah and Sarawak, Borneo is described herein. Johnius sasakii sp. nov. can be separated from the close congeners, Johnius heterolepis and Johnius carouna by having less gill rakers on the lower limb of the first gill arch (mode number 9 vs. 10 for J. heterolepis; 11 for J. carouna). It can be distinguished from J. heterolepis with the higher modal number of gill rakers on the upper limb of first gill arch (5 vs. 4), shorter anal-fin base length (9% vs. 10% of SL) and first anal-fin ray length (1012% vs. 1213% of SL) respectively. Furthermore, J. sasakii sp. nov. can be further differentiated from J. carouna by its shorter second anal-fin spine length 710% SL (usually 810%) vs. 1114% SL (usually 1112%) and slightly deeper body depth 2529% SL (usually 2628%) vs. 2328% SL (usually 2426%). Meanwhile, J. sasakii sp. nov. can be easily differentiated from J. macrorhynus by a present of molariform teeth on inner rows of jaws and stumpy gill rakers. Johnius (Johnius) sasakii sp. nov. can be clearly distinguished from species of the subgenus J. (Johnieops) by the lack of enlarged outer row teeth on upper jaw. A Kimura 2-parameter genetic distance comparison of 450 bp sequences of mitochondrial 16S rRNA and 488 bp nuclear gene S7 showed that J. sasakii sp. nov. are highly differentiated from J. heterolepis (16S: 10.4%, S7: 5.8%), J. carouna (16S:19.3%, S7:8.4%); and J. macrorhynus (16S: 16.7%, S7: 8.1%) respectively. The study highlights that the genetic approach from mtDNA and nDNA can contribute to the confirmation of taxonomic status of sympatric species in genus Johnius.
本文描述了产自东马来西亚沙巴和砂拉越沿海水域的一种新的笛鲷科鱼类，即沙氏笛鲷（Johnius sasakii）。沙氏笛鲷（Johnius sasakii）可通过第一鳃弓下肢的鳃耙数（模式数 9 对 J. heterolepis 的 10；J. carouna 的 11）与近缘种，如花鲈（Johnius heterolepis）和金线鱼（Johnius carouna）相区分。它可以通过第一鳃弓上肢的较高鳃耙数模式数（5 对 J. heterolepis 的 4）、较短的臀鳍基部长度（9%对 SL 的 10%）和第一背鳍鳍条长度（1012%对 SL 的 1213%）与花鲈相区分。此外，沙氏笛鲷（Johnius sasakii）可通过较短的第二背鳍棘长 710% SL（通常为 810%）对 1114% SL（通常为 1112%）和略深的体高 2529% SL（通常为 2628%）对 2328% SL（通常为 2426%）与金线鱼相区分。同时，沙氏笛鲷（Johnius sasakii）可通过内齿列的臼齿状牙齿和短而钝的鳃耙与巨口鱼（Johnius macrorhynus）相区分。沙氏笛鲷（Johnius sasakii）可通过上颌无外齿列增大牙齿与约翰氏笛鲷（Johnieops）亚属的物种明显区分。线粒体 16S rRNA 和核基因 S7 的 450 bp 序列的 Kimura 2-参数遗传距离比较表明，沙氏笛鲷（Johnius sasakii）与花鲈（Johnius heterolepis）（16S：10.4%，S7：5.8%）、金线鱼（Johnius carouna）（16S：19.3%，S7：8.4%）和巨口鱼（Johnius macrorhynus）（16S：16.7%，S7：8.1%）高度分化。该研究表明，来自 mtDNA 和 nDNA 的遗传方法有助于确认笛鲷属中同域物种的分类地位。
