A new deepwater gurnard of the genus Pterygotrigla (Scorpaeniformes: Triglidae) from the southwestern Indian Ocean Author Yato, Takuji Author Heemstra, Elaine text Zootaxa 2019 2019-12-06 4706 1 189 200 journal article 24700 10.11646/zootaxa.4706.1.8 e0d013c3-2082-4403-9f98-c074bbd4ca46 1175-5326 3565217 F5A0AEFC-E8D3-4874-8906-EDDCD3C5054D Pterygotrigla ( Otohime ) madagascarensis sp. nov. Madagascar Deepwater Gurnard (Japanese name: Madagasukaru-sokohoubou) ( Figs. 3 & 4 , Tables 1 & 2 ) Holotype . SAIAB 203807 , 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. 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 . 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 ). 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. FIGURE 3 . Pterygotrigla ( Otohime ) madagascarensis sp. nov . , SAIAB 189644, paratype, 101.4 mm SL. Dorsal view of fresh color. Photograph by M. Lee, AV2010. Coloration of holotype in preservative ( Fig. 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). FIGURE 4 . Pterygotrigla ( Otohime ) madagascarensis sp. nov . , SAIAB 203807, holotype, 109.0 mm SL. A: lateral view, B: dorsal view. 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 . 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 . 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 ); no papilla on the dorsal surface of oral cavity (vs. many papillae, Fig. 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 . 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 ), 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 . TABLE 1. Meristic and morphometric characters of Pterygotrigla ( Otohime ) madagascarensis sp. nov. , P . ( O .) multipunctata , P . ( O .) urashimai and P . ( O .) amaokai .

Species	P . ( O .) madagascarensis Holotype Paratype		P . ( O .) multipunctata	P . ( O .) urashimai	P . ( O .) amaokai
Number of specimens	n = 1	n = 1	n = 5	n = 2	n = 9
Counts
1st Dorsal-fin spines	7	7	7-8	8	7-8
2nd Dorsal-fin rays	12	12	12	13	11-12
Anal-fin rays	12	12	12	12	11-12
Pectoral-fin rays (connected)	13	13	13	13	13
Pelvic-fin rays	I,5	I,5	I,5	I,5	I,5
Caudal-fin rays (branched)	5+4	5+4	5+4	5+4	5+4
LL Scales	56	56	56-60	55	54-61
Bony plates	10	10	10	9	9-10
Gill rakers (right side)	1+9	1+11	0-2+8-10	1-2+8	1-2+10-16
Vertebrae with urostyle	10+17	10+17	10+17	10+17	10-11+16-17
Form *
Posttemporal spine reaching	3rd D1	2nd D1	not 1st-3rd D1	-	1st-2nd D1
Opercular spine reaching	3rd D1	4th D1	3rd-4th D1	3rd D1	3rd-5th D1
Pectoral-fin reaching	7th A	6th A	5th-8th A	9th A	4th-7th A
1st detached pectoral-fin ray reaching	5th A	3rd A	not 1st-5th A	6th-7th A	3rd-6th A
Pelvic-fin reaching	1st A	anus	anus-1st A	2nd A	anus-2nd A
Measurements (mm)
Total length	134.5	125.7	107.0-192.0	100.7-115.0	114.9-168.0
Standard length	109.0	101.4	85.8-158.0	81.1-93.0	94.7-137.0
% of Standard length
Distance from snout to 1st dorsal fin	42.0	45.4	40.4-43.6	46.2-46.5	41.0-42.7
Distance from snout to 2nd dorsal fin	63.4	66.6	63.5-65.5	64.7-66.3	62.7-65.2
Distance from snout to pectoral fin	37.5	36.7	34.6-38.5	37.5-40.3	35.5-38.8
Distance from snout to pelvic fin	33.9	33.2	32.5-35.8	32.4-36.9	31.5-38.5
Distance from snout to anal-fin	61.0	61.8	59.7-65.4	58.8-61.9	60.6-64.6
Body depth in front of 1st dorsal fin	26.8	27.1	26.4-29.1	26.9-27.7	25.4-29.3
Body width at cleithral base	20.8	21.7	18.1-21.7	20.7-20.9	19.9-22.9
Caudal peduncle length	12.1	13.3	12.2-13.7	12.7-12.9	11.0-14.0
depth	6.2	6.2	5.8-6.6	6.5-6.7	5.6-6.4
1st Dorsal-fin base length	17.8	18.4	19.4-19.9	19.9-21.0	17.5-19.7
2nd Dorsal-fin base length	24.1	24.4	23.8-26.2	26.5-29.2	22.3-26.5
Anal-fin base length	27.8	26.2	25.5-29.7	25.8-28.5	26.1-28.2
Head length	39.0	39.5	36.8-40.9	42.2	38.8-40.8
Length of 1st detached pectoral-fin ray	39.2	34.8	30.0-39.5	41.6	33.1-39.0
Length of 2nd detached pectoral-fin ray Length of 3rd detached pectoral-fin ray	32.4 28.7	31.4 28.5	25.6-33.7 23.6-29.8	34.8 31.1	28.5-34.3 26.4-30.2
Pectoral fin length	39.7	43.9	37.1-44.3	44.0-49.3	35.0-39.4
Pelvic fin length	28.0	28.3	25.6-28.2	28.2-29.0	26.2-30.1

...continued on the next page TABLE 1. (continued)

Species	P . ( O .) madagascarensis		P . ( O .) multipunctata	P . ( O .) urashimai	P . ( O .) amaokai
Holotype	Paratype
Number of specimens	n = 1	n = 1	n = 5	n = 2	n = 9
Length of 1st spine of first dorsal fin	-	14.3	11.7-14.3	14.0-14.1	12.1-14.3
Length of 2nd spine of first dorsal fin	17.4	-	15.9-18.6	18.6-18.7	16.3-20.2
Length of 3rd spine of first dorsal fin	-	-	18.3-20.6	20.0-20.5	18.0-21.9
Length of 4th spine of first dorsal fin	15.3	-	16.1-18.8	16.6-16.8	15.0-18.9
Length of 5th spine of first dorsal fin	11.7	-	11.2-12.9	-	7.2-13.9
Length of 6th spine of first dorsal fin	8.3	-	6.5-9.8	-	5.4-9.5
Length of 7th spine of first dorsal fin	4.6	-	3.8-5.8	-	2.8-6.4
Length of 8th spine of first dorsal fin	1.9	-	0.9-1.6
% of Head length
Head depth at middle of orbit	59.8	61.1	59.6-65.4	59.2-61.4	56.8-62.0’
Head width at preopercle	49.6	53.9	44.5-57.9	52.3-52.6	47.9-60.8
Snout length	33.9	35.2	35.8-39.0	35.1-38.0	32.0-36.9
Height of suborbital stay	16.9	18.5	16.9-21.2	17.6-18.1	15.4-18.9
Distance between rostral projection tips	18.8	21.4	18.0-22.5	17.9	18.0-19.7
Upper jaw length	39.3	41.1	38.5-43.2	41.8\42.3	41.2-46.5
Lower jaw length	47.1	49.1	44.9-50.0	48.2-49.7	45.5-50.6
Orbit diameter	34.8	32.7	29.7-32.6	33.9-34.9	31.6-35.9
Interorbital width	31.8	31.2	27.1-30.0	32.7-33.2	28.4-32.0
Opercular spine length	42.8	48.9	47.4-48.7	37.8-42.4	41.0-48.8
% of Orbit diameter
Opercular spine length	123	149	138-160	108-125	121-149

* “3rd D1” meaning 3rd spine of first Dorsal fin, “7th A” meaning 7th anal-fin ray. 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 , 102.4 mm SL .