Pristolepis pentacantha Plamoottil 2015

Prakash, Anjana Preetha, Raghavan, Rajeev, Dahanukar, Neelesh, Anoop, V. K., Thampy, Dencin Rons, Britz, Ralf & Ali, Anvar, 2025, Pristolepis pentacantha Plamoottil 2015, and Catopra tetracanthus Günther 1862: two junior synonyms of Pristolepis marginata Jerdon 1849, Zootaxa 5642 (3), pp. 245-259 : 249-254

Pristolepis pentacantha Plamoottil 2015 :

a junior synonym of P. marginata

Plamoottil (A), and subsequently Plamoottil (B) suggested that Pristolepis pentacantha can be distinguished from P. marginata in lacking pre-orbital serrations, having fewer pre-opercular serrae, more anal-fin spines, and fewer dorsal-fin rays. An examination of fresh topotypes and museum specimens of both species, however, suggests that these characters are unreliable and do not diagnose the two taxa. For example, P. pentacantha was suggested to have 11 dorsal-fin rays (based on the holotype and single paratype) (Plamoottil (A, B)), but an examination of a fresh topotype and additional specimens (n=6) from the same river (three representative specimens with the same genetic identity) reveals that the five-spined Pristolepis possess 11–12 dorsal-fin rays, a count that overlaps that in P. marginata (11–12; n=23).

Two additional characters that were used to distinguish Pristolepis pentacantha from P. marginata were the absence of preorbital serrations, and a preopercle with 5–6 serrae (Plamoottil (A), p. 552). It is evident that Plamoottil (A) overlooked the presence of preorbital (lachrymal) serrae, which are present in topotypic P. pentacantha as well ( Fig. 4.v –vi). In addition, Plamoottil (A) also miscounted the number of pre-opercular serrae in P. marginata as 18. Topotypic and additional specimens of P. marginata have only 3–12 pre-opercular serrae (n=9). Other characters and counts considered diagnostic for P. pentacantha also overlap between P. pentacantha and P. marginata (see Table 1 ).

Analysis of the size-corrected morphometric data of P. pentacantha and P. marginata show no significant differences (PERMANOVA, F = 8757, P = 0.4429) between the two, with both species clusters overlapping in the NMDS analysis ( Fig. 5 ), indicating that the two species cannot be distinguished based on morphometric characters.

Due to the lack of diagnostic molecular or morphological characters between the four- and the five-spined Pristolepis , we synonymize Pristolepis pentacantha Plamoottil, 2015 with P. marginata Jerdon, 1849 .

Figures

FIGURE 4. Cleared and stained topotypic specimens of (i) Pristolepis pentacantha and (ii) P. marginata: DFS- Dorsal-fin spines, DFR-Dorsal-fin rays, CFR-Caudal-fin rays, AFS-Anal-fin spines, AFR- Anal-fin rays and PFR-Pectoral-fin rays. Scales between the preopercle's ventral edge and the orbit's ventral rim (4 each) in (iii) P. pentacantha and P. marginata. Preorbital serrations in (v) P. pentacantha and (vi) P. marginata.

FIGURE 5. Non-metric multidimensional scaling of size-corrected morphometric data of Pristolepis marginata and P. pentacantha. The 95% confidence ellipses of both species overlap, strongly suggesting no significant difference between the two. Shepard’s plot explaining the stress is provided in the inset.