Pterygotrigla (Otohime) madagascarensis, Yato & Heemstra, 2019

Yato, Takuji & Heemstra, Elaine, 2019, A new deepwater gurnard of the genus Pterygotrigla (Scorpaeniformes: Triglidae) from the southwestern Indian Ocean, Zootaxa 4706 (1), pp. 189-200 : 192-196

publication ID	https://doi.org/ 10.11646/zootaxa.4706.1.8
publication LSID	lsid:zoobank.org:pub:F5A0AEFC-E8D3-4874-8906-EDDCD3C5054D
DOI	https://doi.org/10.5281/zenodo.5612648
persistent identifier	https://treatment.plazi.org/id/03BCBF56-FFFC-FF87-FF74-FC21FC84CF97
treatment provided by	Plazi
scientific name	Pterygotrigla (Otohime) madagascarensis
status	sp. nov.

Treatment

Pterygotrigla (Otohime) madagascarensis sp. nov.

Madagascar Deepwater Gurnard (Japanese name: Madagasukaru-sokohoubou)

( Figs. 3 View FIGURE 3 & 4 View FIGURE 4 , Tables 1 View TABLE 1 & 2 View Table 2 )

Holotype. SAIAB 203807 About SAIAB , 109.0 mm SL (134.5 mm TL), Sud Cap Sainte Marie , Madagascar, southwestern Indian Ocean 26°13’S, 45°8’E, R/ V Antéa, stn. CP3614, 250─ 300 m, 14 May, 2010. GoogleMaps

Paratype. SAIAB 189644, 101.4 mm SL (125.7 mm TL), same locality and collection details as the holotype .

Diagnosis. Dorsal-fin spines 7; dorsal-fin rays 12; pectoral-fin rays 13 + 3 detached rays; rostral spine short and directed slightly outwards; no cleithral spine; 10 bony plates along the 1st dorsal-fin base, plates in the posterior half (6th─10th) very small and slightly embedded in skin; no fleshy papillae on the dorsal surface of oral cavity; no large spot on 1st dorsal fin; one row of blackish spots present on 2nd dorsal fin; inner surface of pectoral-fin membrane blackish except for the margin, and with a jet-black oval area subequal to eye near the fin base, and each ray somewhat dusky.

Description. Counts and measurements of holotype and paratype are shown in Table 1 View TABLE 1 .

The description is based on the holotype, followed by the paratype in parentheses when it differs from the holotype.

Body robust, somewhat compressed. Head large, 39% of SL (40%), covered with bones bearing many minute granules. Rostral projection of one short spine on each side of head, 11.5% of HL (13.2%), with weak serrations on the outer margin, and both spines directed very slightly outwards. Upper profile of snout concave, the length subequal to orbit diameter, 97.4% of orbit diameter (107.6%). Nostrils two, the anterior one with a short tubular membrane and the posterior a simple slit, situated halfway along the snout. No spines around orbit and nasal area. Orbit oval, and rather large, 34.8% HL (32.7%). No suborbital ridge. Height of suborbital stay low, 16.9% HL (18.5%). Interorbital space deeply concave and the width less than orbit diameter, 31.8% HL (31.2%). Mouth large, upper jaw extends back beyond a vertical through the anterior margin of orbit, about 1/3 (1/2) the orbit diameter. The posterior end of lower jaw extends beyond a vertical through the middle (to the rear quarter) of orbit. Teeth on both jaws villiform, in a narrow band, with a few villiform teeth on prevomer. No teeth on palatine. No papillae on the dorsal surface of oral cavity. Gill rakers long, 1 + 9 (1 + 11) on the first arch.

Posttemporal spine on the right side, short and pointed, the tip reaching to the base of 3rd spine of the first dorsal-fin; left posttemporal spine a little broken (the tip of posttemporal spine on left and right sides reaching to the base of 2nd spine of the first dorsal fin in paratype). Two sharp preopercular spines present, the upper one longer than the lower. Opercular spine very long and stout, 123% of orbital diameter (144%), the tip extending posteriorly below the base of the 3rd spine of the first dorsal fin (reaching the 4th spine). No cleithral spine, posterior part of cleithrum a triangular plate.

Dorsal spines sharply pointed, anterior edge weakly serrated except for uppermost quarter; first and third dorsal spines of holotype slightly broken at the tip, but the third spine is longest (first spine slightly longer than orbit diameter; the other spines broken). Anal fin inserted below the origin of second dorsal fin. Caudal fin deeply emarginate. Pectoral fin fairly long, reaching a vertical through the base of 6th ray of second dorsal fin (5th); the lower three rays detached completely, the uppermost ray longest, reaching the base of 5th anal-fin ray (3rd). Pelvic fin moderately long, reaching past the anus to the anal-fin insertion (reaching anus).

Bony plates (modified flat processes of the pterygiophores) closely associated with each other along the first dorsal-fin base; the anteriormost ones of right and left sides are united, forming one plate in front of the first dorsal spine base, the 3rd plate largest, size of each plate decreasing posteriorly and 6th–8th plates are embedded under skin, 9th and 10th plates on left and right are united, forming a single plate, respectively. No bony plates along second dorsal-fin base.

Scales on body very small, cycloid. Nape, near the bony plates, isthmus, breast, and around the base of paired fins naked. The dorsal and anterior half of the body with irregularly arranged scales embedded under the skin, and not touching each other. Scales on lateral line small, simple, with an unbranched perforating duct; the shape long and elliptical anteriorly, without any spines, diminishing in size towards to the rear end of lateral line. The number of total vertebrae 27 (with urostyle), precaudal vertebrae 10, caudal vertebrae 17.

Fresh coloration (from a dorsal view photograph of the paratype by M. Lee, Fig. 3 View FIGURE 3 ). Dorsal surface of head and body pinkish orange color, with many small dark green ocelli present on the dorsal body, and having three faint reddish bands, one each at first dorsal-fin base, at second dorsal-fin base, and at caudal peduncle. Caudal fin proximal half whitish, distal half yellowish. Inner surface of pectoral fin black except for the dusky rays and narrow yellowish posterior margin.

Coloration of holotype in preservative ( Fig. 4 View FIGURE 4 ). Head brown, body and median fins light brown. Upper half of body with many small dark brownish blotches; some small blackish blotches present on the first dorsal-fin membranes from 2nd to 5th spines; second dorsal fin with one longitudinal row of small blackish blotches present. Outer surface of pectoral fin mostly covered with blackish elliptical shape, except proximally at the base, narrow margins, and on the rays; the inner surface, lower three connected rays (11th to 13th rays) and membrane whitish, membrane between 1st and 11th rays black, 1st to 3rd rays white, 4th to 10th rays dusky white except near the base which is jet-black (Fig. 5).

Size. Attains at least 109 mm SL.

Distribution. Known from the type specimens taken at a single station south of Madagascar in the southwestern Indian Ocean, in 250─ 300 m.

Etymology. The specific name “ madagascarensis ” refers to the type locality for the species.

Comparisons. Pterygotrigla (Otohime) madagascarensis sp. nov. is clearly distinguished from other species of the subgenus Otohime except for P. (O.) amaokai , P. (O.) urashimai and P. (O.) multipunctata , by having the following combination of characters: no cleithral spine, breast and front of pectoral-fin base naked, no white ocellus on inner surface of pectoral fin, see Table 2 View Table 2 .

Pterygotrigla (Otohime) madagascarensis sp. nov. is easily distinguished from P. (O.) urashimai , by the following characters: dorsal-fin spines 7 (vs. 8 in P. (O.) urashimai ), second dorsal-fin rays 12 (vs. 13); bony plates 10 (vs. 9); second dorsal fin with one row of blackish botches (vs. two rows); head length 39.0–39.5% SL (vs. 42.2%); depth of caudal peduncle 6.2% SL (vs. 6.5–6.7%), and shorter pectoral fin reaching 6th–7th anal ray (vs. 9th anal ray), see Table 1 View TABLE 1 .

Also P. (O.) madagascarensis sp. nov. can be separated from P. (O.) multipunctata , by having one row of blackish botches on second dorsal fin (vs. two rows, Fig. 8 View FIGURE 8 ); no papilla on the dorsal surface of oral cavity (vs. many papillae, Fig. 9 View FIGURE 9 ). Further, P. (O.) madagascarensis sp. nov. has a larger orbit and shorter snout than the latter species, length of orbit diameter 32.7–35.9% HL (vs. 29.7–32.6%), interorbital width 31.2–31.8% HL (vs. 27.1–30.5%), snout length 32.0–35.2% HL (vs. 35.8–39.0%), see Table 1 View TABLE 1 .

Some specimens of P. (O.) amaokai have a few scales (3 or 4) on the breast and front of the pectoral fin base (vs. breast and pectoral-fin base naked). P. (O.) madagascarensis sp. nov. differs from P. (O.) amaokai in having one row of blackish botches on second dorsal fin (vs. two rows, Fig. 8 View FIGURE 8 ), narrow pale margin of inner surface of pectoral fin and dusky on the rays (vs. wider white margin and unpigmented rays in P. (O.) amaokai (Fig. 5), longer pectoral-fin 39.7–43.9% of HL (vs. 35.0–39.4% in P. (O.) amaokai ), shorter upper jaw 39.3–41.1% of HL (vs. 41.2–46.5%), see Table 1 View TABLE 1 .

IGURE 5 . Inner surface of pectoral fin. A: Pterygotrigla (Otohime) madagascarensis sp. nov., SAIAB 203807, holotype, 109.0 mm SL. B: P. (O.) amaokai MNHN 2016-0318 About MNHN , 102.4 mm SL .