The article titled “Phenotypic Variation in Freshwater Murrel, Channa punctatus (Bloch, 1793) from Northern and Eastern Regions of India Using Truss Analysis” [1] is related to the authors’ previous article: Kashyap, A., Awasthi, M. & Serajuddin, M. Proc. Natl. Acad. Sci., India, Sect. B Biol. Sci. (2016) 86: 367. doi: 10.1007/s40011-014-0451-3. Though the earlier publication was cited as reference [4], the relation between the two articles was not thoroughly discussed.
The articles both studied subpopulations of C. punctatus and discovered there are intraspecific variations that exist between them. Further molecular studies are needed to establish the existence of multiple stocks of Channa punctatus, as concluded in the two articles.
The earlier study was performed on 193 samples; 163 samples were from Lucknow, while 30 samples were from Kolkata. In this article, 90 samples were collected from River Gomti at Lucknow and ponds at Kolkata and Malihabad; 30 samples were collected from each location site.
The studies used different methods. We used traditional methods in the earlier article while adopting modern methods in this article. The traditional method included length-weight relationship and the usage of a measuring board and fine-pointed divider of calipers to measure 17 morphometric and 5 meristic traits. We also studied the intraspecific divergence by formulae such as the cube law as given by Lecren and coefficient of difference as given by Mayre.
In this article, the truss study that is based on image analysis is performed using software and a digital camera. We used 23 truss measurements based on landmarks. In addition, we depended on Paleontological Statistics to analyze the two-dimensional shapes.
This article supports the notion that intraspecific variations occur due to shape. Meanwhile, they occurred due to morphometric and meristic traits in the earlier article. Moreover, the earlier article showed that length-weight relationship equations are evaluated to point out the growth patterns, such as isometric and allometric growth, while there was no length-weight for growth in this article.
Furthermore, in the earlier article, the maximum value of coefficient of difference (CD) was obtained in case of snout length and interorbital length. Additionally, it was noticed that 14 morphometric parameters out of 17 and 3 out of 5 meristic characters were found to be significantly different in two subpopulations.