A New Stolephorus (Teleostei: Clupeiformes: Engraulidae: Engraulinae) from the Red Sea

Abstract

The new anchovy Stolephorus meteorum, formerly confused with Stolephorus indicus, is described on the basis of 19 specimens collected from the southern Red Sea. Four other species, previously confused with or placed in the synonymy of S. indicus, have been either redescribed (Stolephorus commersonnii), described as new (Stolephorus belaerius), or resurrected from its synonymy (Stolephorus balinensis and Stolephorus scitulus). The new species shares with the latter four species, plus S. indicus, a relatively short maxilla and pelvic fins, and six or fewer prepelvic scutes but differs from them in the combination of some other characters, including intermediate numbers of gill rakers (total gill rakers on first gill arch 40-43, modally 41), 41 vertebrae, a large head and narrower interorbital area, and longer pelvic fins. A genetic analysis of the mitochondrial cytochrome oxidase I gene (COI) of S. meteorum, new species, S. balinensis, S. belaerius, and S. indicus revealed each species to be genetically divergent from the others by 2.5-3.6% uncorrected distance. STOLEPHORUS, an Indo-Pacific genus of marine and/or brackish water anchovies (Clupeiformes: Engraulidae), comprises 43 valid species (

Resurrection and redescriptions of nominal species previously regarded as synonyms of Thrissina mystax (Bloch and Schneider, 1801) (Teleostei: Clupeiformes: Engraulidae)

“…Body strongly compressed laterally. dark lines on dorsum) Hata et al, , 2021Hata et al, , 2022aHata, Lavoué, Bogorodsky, et al, 2023;Hata, Lavoué, Chunthanawong, & Motomura, 2023;Whitehead et al, 1988;Wongratana et al, 1999). Comparisons of T. mystax with T. porava and T. valenciennesi are given in "Comparisons" under each species.…”

“…valenciennesi vs. 28.1%-31.1% in T. mystax; Figure 7d) and a lower number of 4TGR (14-17 [rarely 18] vs. 19-22 [18]; Figure 6d). In fact, the gill raker numbers on each gill arch are an important diagnostic character in various clupeiform fishes (Agostinho et al, 2022;Gangan et al, 2020;Kimura et al, 2009;Singh et al, 2021;Whitehead et al, 1988), and even 4TGR numbers (gill rakers on innermost gill arch) can be a distinguishing character in some cases (Hata et al, 2022b;Hata, Lavoué, Bogorodsky, et al, 2023;Hata, Lavoué, Chunthanawong, & Motomura, 2023). However, it appears to be rare that two apparently closely related species differ significantly in 4TGR number, even though no differences exist in GR numbers on other gill arches.…”

Description of Stolephorus horizon n. sp. from Fiji and Tonga, and redescription of Stolephorus scitulus (Fowler, 1911) (Teleostei: Clupeiformes: Engraulidae)

“…However, the new species can be distinguished from all species of Stolephorus indicus Group by having the pectoral fin without melanophores (melanophores scattered on several pectoral-fin rays in the former; Figure 3B). [2] for gill raker numbers in S. balinensis, S. belaerius, S. commersonnii, S. indicus, and S. meteorum], a longer pelvic fin (8.0-9.9% of SL vs. 5.6-9.2%), and greater distances between the pectoral and pelvic fin insertions (18.8-21.1% of SL vs. 15.1-20.8%), and snout to pelvic-fin insertion (43.1-46.2% of SL vs. 39.7-46.5%) (Figure 12). In addition, S. horizon differs from S. belaerius in having higher gill raker numbers [2] for vertebral numbers in balinensis, S. belaerius, S. commersonnii, S. indicus, and S. meteorum], a shorter pelvic fin (8.0-9.9% of SL vs. 7.9-10.3%) and narrower body (16.4-18.6% of SL vs. 17.8-19.8%) (Figure 13).…”

“…Stolephorus Lacepède, 1803, an Indo-Pacific genus of marine and/or brackish water anchovies (Clupeiformes: Engraulidae), was reviewed by Whitehead et al (1988) [1], who recognized 18 valid and 1 undescribed species (currently, the genus comprises at least 44 valid species [2]). In that review, species characterized by a short maxilla, posteriorly just reaching or extending slightly beyond the anterior margin of preopercle, the depressed pelvic fin posteriorly not reaching to vertical through the dorsal-fin origin, 6 or fewer pelvic scutes on the abdomen, and 28 or fewer gill rakers on lower limb of first arch (1LGR) had been treated as a single, widely-distributed Indo-Pacific species, Stolephorus indicus (van Hasselt, 1823) (Figure 1).…”

“…Subsequently, Hata et al (2021) [3] showed that the latter included five species [viz., Stolephorus balinensis (Bleeker, 1849), Stolephorus belaerius Hata, Lavoué and Motomura, 2021, Stolephorus commersonnii Lacepède, 1803, S. indicus, and Stolephorus scitulus (Fowler, 1911)]. In addition, Hata et al (2023) [2] described a new species from the Red Sea, Stolephorus meteorum Hata, Lavoué, Bogorodsky, Alpermann, and Motomura 2023, which had also been previously confused with S. indicus. As the investigation of Stolephorus progressed, specimens from Fiji and Tonga, treated as S. scitulus by Hata et al (2021) [3], were found to differ significantly from true S. scitulus (confirmed herein as restricted to Society Islands) in several characters, including pectoral fin without melanophores and lower gill-raker counts.…”