Plectropomus, Oken, 1817

Ma, Ka Yan & Craig, Matthew T., 2018, An Inconvenient Monophyly: An Update on the Taxonomy of the Groupers (Epinephelidae), Copeia 106 (3), pp. 443-456 : 451-452

Plectropomus and Its Allies.

—The genus Plectropomus was recovered as monophyletic; however, both the monotypic Gonioplectrus and Saloptia are included in a larger monophyletic clade. All three genera share a relatively low dorsal-fin spine count (7–8 vs. 9–11 in the remaining grouper genera). Smith (1964), Leis (1986), and Heemstra and Randall (1993) hypothesized a close relationship between Saloptia and Plectropomus . Species in these genera are the only groupers with a single supraneural bone, low dorsal-fin spine count, three large antrorse spines on the lower edge of the preopercle, and only 13 branched caudal-fin rays. Saloptia has been treated as a monotypic genus on the basis of the relative strength of the median fin spines (‘‘strong’’ in Saloptia and ‘‘weak’’ in Plectropomus ; Heemstra and Randall, 1993) and an absence of enlarged canine teeth on the lower jaw. Given the numerous synapomorphies shared by these genera, the argument for retaining S. powelli in a monotypic genus is relatively weak. The loss of canine teeth appears to be an autapomorphic character and is insufficient to exclude the species from Plectropomus .

The monotypic genus Gonioplectrus is also present in this clade (clade A, Figs. 1 , 2 ). This is not entirely surprising as it shares the low number of dorsal-fin spines (8) with species of Plectropomus . Gonioplectrus has two well-developed supraneurals (versus only one in Plectropomus and Saloptia ), 15 branched caudal-fin rays (versus 13 in Plectropomus and Saloptia ), a prominent knob on the lower corner of the maxilla (absent in Cephalopholis, Plectropomus , and Saloptia ) and unique cranial morphology (Heemstra and Randall, 1993). Given these differences, Gonioplectrus appears to be a related, but distinct genus and is retained for the single species G. hispanus .

Also included in the monophyletic clade A ( Fig. 1 ) are members of the genus Variola . With nine dorsal-fin spines, this genus would seem to be closely related to Cephalopholis ; however, it is clear from the analyses that this is not the case. Species of Variola are the only grouper species with a pronounced, lunate tail. While closely allied with Plectropomus and Gonioplectrus , the genus Variola appears to be a distinct group among the groupers with low dorsal-fin spine counts and is therefore retained.

Figures

FIG. 1. Majority rule consensus cladogram of maximum likelihood analysis, reconstructed using RAxML with 1000 bootstrap replicates following Ma et al. (2016). Numbers at nodes represent bootstrap support values (%).

FIG. 2. Bayesian inference phylogram reconstructed using MrBayes following Ma et al. (2016). Numbers on branches represent posterior probabilities.