Ceratothoa carinata

Ceratothoa carinata (Bianconi, 1869) Figure 1–2 Synonymy. A full synonymy of Ceratothoa carinata (Bianconi, 1869) is provided by Aneesh et al. (2022). Type locality. Mozambique; a neotype was designated from Maputo Bay, Mozambique by Hadfield et al. (2016). Material examined. 2♀♀ (ovig., 29 mm long, 12 mm wide; 24.8 mm long, 11 mm wide), 1♂ (24 mm long, 10.5 mm wide); collected in buccal cavity of Talang queenfish, Scomberoides commersonnianus; from a commercial fishing boat near the city of Chabahar; the Gulf of Oman; 25°26’ N; 60°64’ E; 15 March 2023; coll. M. Salari (ZMSU- 1070). Description of male (a male from the Gulf of Oman, Iran). Body length 24 mm, width 10.5 mm, about 2.3 times as long as greatest width, widest at pereonite 4, most narrow at pereonite 1, medial longitudinal ridge present. Cephalon 0.66 times longer than wide, proximal and distal margins straight, proximolateral corners right-angled; frontal margin blunt. Eyes submarginal, one eye 0.14 times width of cephalon; 0.16 times the length of cephalon. Pereonite 1 longest, middle length about 1.5 times as long as cephalon, anterior border straight, anterolateral corner with small distinct projection, extended to the middle of the eye. Pereonite 4 about 1.25 times as long as pereonite 2, 6 times as long as pereonite 7. Pleon with all pleonites visible in dorsal view; pleonite 1 most narrow; pleonites 2–5 progressively wider; pleonite 5 widest, posterior margin produced medially. Pleotelson 0.48 times as long as anterior width, dorsal surface with 2 sub-medial depressions, posterior margin deeply concaved. Antennula (Fig. 1D) with 8 articles; peduncle articles 1 stouter than article 2; flagellum with 5 articles. Antenna (Fig. 1E) with 8 articles; peduncle article 1 longest, 0.9 times as wide as long; flagellum with 4 articles, progressively decreasing in width posteriorly. Mandibular process (Fig. 1F) ending in acute incisor, mandible palp article 2 and 3 with fine setae on mesiolateral margin, article 3 with a terminal seat. Pereopod 1 (Fig. 1G) basis 1.5 times as long as greatest width; ischium 0.9 times as long as basis; merus 0.45 times as long as ischium; carpus 0.4 times as long as merus, with straight distal margin; propodus 1.4 times as long as wide. Pereopod 4 (Fig. 1H) basis 1.55 times as long as greatest width; ischium 3.3 times as long as merus; carpus 0.66 times as long as merus, with straight distal margin; propodus 1.42 times as long as wide. Pereopod 7 (Fig. 2I) basis moderately wide, well-developed carina, 1.1 times as long as greatest width; ischium subequal length with basis, inferior margin with an enlarged carina; merus 0.42 times as long as wide, 0.3 times as long as ischium; carpus 0.83 times as long as merus, without bulbous protrusion; propodus 1.2 times as long as wide. Pleopods 1–3 (Fig. 2A–C) are similar, without setae as illustrated; pleopod 2 lacks an appendix masculine. Pleopods 4–5 (Fig. 2D, E) are similar as illustrated. Uropod (Fig. 1J) as long as pleotelson; peduncle as long as endopod, 0.87 times as long as exopod, peduncle lateral margin without setae; rami extending just beyond pleotelson, marginal setae absent, apices narrowly rounded. Host. Talang queenfish, Scomberoides commersonnianus Lacepède, 1801 (the present study). Remarks. Previous records and descriptions of Ceratothoa carinata were all based on female specimens. In this study, we report both male and female specimens, providing the first description of a male. Our specimens, both male and female, align well with the diagnoses of C. carinata, which include: a medial ridge extending longitudinally along the dorsal pereon surface; a head with a truncated frontal margin; a rectangular pleotelson that is wider than long, with two sub-medial depressions and a deeply concave posterior margin; pereopod 7 with a well-developed carina on the inferior margin of the ischium and the superior margin of the basis; and uropod rami extending to the distal edge of the pleotelson (Martin et al. 2013). As we obtained COX1 sequences from both male and female specimens, genetic evidence further supports their conspecificity.