Figure 1.
Map Showing sampling sites within the Narmada River basin and its tributaries.
Table 1.
Sampling stations on the Narmada River basin.
Figure 2.
Comparison of fish species with species records from earlier studies. (*specific species to the study; **common species for two studies; ***common species for all studies).
Figure 3.
Distribution of conspecific and congeneric K2P mean divergence of 83 fish species from the Narmada River (ascending order).
The maximum conspecific divergence (2.9%, blue solid circles) and minimum congeneric divergence (4.66%, black hollow circle) represent the threshold level of conspecific and congeneric divergence respectively. Data series were represented by more than one sequence. 93% of the total 83 species showed divergence below ≤1% and represented true species.
Figure 4.
K2P divergence based Neighbor-joining tree of 314 CO1 sequences from 83 fish species from the Narmada River system.
(The number of specimens analyzed is shown after each species name).
Table 2.
Genetic divergence (K2P) within various taxonomic levels.
Figure 5.
Automatic Barcode Gap Discovery (ABGD) based partition of the data set.
We report the number of groups inside the partitions (primary and recursive) as a function of the prior limit between intra- and interspecies divergence. The initial partition is denoted by (o) and recursive portion denoted by (#) and dotted line represents the threshold value (P = 0.0215) for defining species boundary from the Narmada River using COI sequences.
Figure 6.
NJ tree based on K2P values showing hidden diversity showing the species having deep conspecific divergence (>2) and various approaches to resolve the putative new species status (Hollow rectangles are treated as confirmation of tested approach).
(A) morphological approach (B) Traditional barcode gap approach (>3% divergence or divergence to the magnitude of 10X of mean intraspecific divergence values of nearest species [44] (C) phylogenetics with bootstrap support and (D) ABGD method of recursive partition of sequences into groups using intra and inter specific divergence (P). (Underline represent sequences obtained from NCBI genebank, P1–5 are putative new species).
Figure 7.
Boxplot showing distribution of conspecific (S) congeneric (G) and confamilial (F) K2P divergence (%) along the selected sampling stations from the River basin analyzed as upper reach, middle and lower reach (segment).