Dendrochirus tuamotuensis, Matsunuma & Motomura, 2013

Matsunuma, Mizuki & Motomura, Hiroyuki, 2013, A New Lionfish of the Genus Dendrochirus (Scorpaenidae: Pteroinae) from the Tuamotu Archipelago, South Pacific Ocean, Species Diversity 18 (1), pp. 1-7 : 2-5

Dendrochirus tuamotuensis sp. nov.

[New English name: Tuamotu’s Dwarf Lionfish] ( Figs 1–4 ; Table 1 )

Holotype. BPBM 37140 , 57.4 mm SL, Makemo Atoll , Tuamotu Archipelago, French Polynesia, 16°34′12″S, 143°27′06″W, 120 m depth, trap, J. Poupin, 4 June 1990.

Diagnosis. A species of Dendrochirus with the following combination of characters: dorsal fin with 9 soft rays; anal fin with 5 soft rays; pectoral-fin rays 19; no barbel on tip of snout; profile of posterior margin of pectoral fin bilobed (notched at midpoint); body depth 35.4% of SL; body width 18.6% of SL; head length 37.6% of SL; head width 12.9% of SL; orbit diameter 12.9% of SL; postorbital length 15.3% of SL; suborbital ridge with 14–16 spines; pterotic with 8 spines; no large, ocellated spot on soft-rayed portion of dorsal fin.

Description. Morphometrics of the holotype are shown in Table 1 . Characters included in the specific diagnosis are not repeated here. Dorsal fin with 13 spines; anal fin with 3 spines; pectoral fin with 19 (1 upper unbranched + 8 branched+10 lower unbranched) rays; pelvic fin with 1 spine and 5 soft rays. Pored lateral-line scales 24 (right side only, left side damaged); scales above lateral line 6, below 12; scale rows between sixth dorsal-fin spine base and lateral line 6; scale rows between last dorsal-fin spine base and lateral line 6; pre-dorsal-fin scale rows 3; oblique cheek scale rows 3; horizontal cheek scale rows 2; vertical cheek scale rows 0; gill rakers 15 [4 on upper limb+11 on lower limb (8 and 3 rakers on ceratohyal and hypobranchial, respectively)]. Branchiostegal rays 7. Formula for configuration of supraneural bones, anterior neural spines, and anterior dorsal pterygiophores //2+1/1/1/1/1/1/1/1/1+1/1/. Vertebrae 10+ 14=24.

Body oblong, moderately compressed anteriorly, more strongly compressed posteriorly; depth moderate, greater than length of longest dorsal-fin spine. One simple tentacle on posterior edge of low membranous tube associated with anterior nostril, its length distinctly greater than diameter of anterior nostril, its tip extending beyond posterior margin of posterior nostril when depressed posteriorly. One short, simple tentacle on supraocular. No skin flap on orbit; small skin flap on uppermost preopercular spine base; 2 small skin flaps on posterior margin of preopercular. One short tentacle on anterior portion of ventral margin of lacrimal. Relatively large skin flap on tip of posterior lacrimal spine, tip of flap not extending beyond profile of lower jaw when depressed ventrally (lateral view).

Cycloid scales covering head, including cheek, preopercle, and opercle, but absent on snout, preocular, supraocular, postocular, interorbital canal, occiput, upper postorbital area, suborbital pit, maxilla, and mandible. Poorly developed ctenoid scales covering upper anterolateral body surface, cycloid scales covering remaining lateral body surface; scales not extending onto rays or membranes of median fins except basal caudal fin. Exposed cycloid scales covering pectoral-fin base and ventral surface of trunk, including interpelvic space.

Lateral line complete, weakly sloping downward. Sensory pores of cephalic lateralis opening at tips of spine-like tubes. Three sensory pores on underside of each dentary; 1 small pore on each side of symphysial knob.

Mouth moderately large, slightly oblique, forming angle of about 30° to horizontal axis of head and body; upper edge of posterior maxilla swollen laterally, forming low ridge and displaying poorly developed median lateral ridge; posterior margin of maxilla just reaching mid-orbit level. Symphyseal gap separating premaxillary teeth bands distinctly narrower than width of each band; upper jaw with band of small, slender, conical teeth; about 5 tooth rows at front of upper jaw; about 4 tooth rows at front of lower jaw; small teeth in 5 rows forming blunt V-shaped patch on vomer; no palatine teeth.

Dorsal profile of snout relatively steep, forming angle of about 40° to horizontal axis of head and body. Nasal spine with single small, upwardly directed spinous point distally; its length subequal to anterior nostril diameter. No median interorbital ridge. Interorbital ridges moderately developed, separated by narrow channel, diverging posteriorly, conjoined with origins of coronal spines (left side only). Interorbital space moderately deep, with about one-fifth of orbit extending above dorsal profile of head. Coronal spine small with a single spinous point; its length subequal to that of tympanic spine. Tympanic spine small, relatively flattened, with a single spinous point; no extra spine. Preocular with 2 (4 on right side) small spines on outer edge. Supraocular spine with 3 spinous points. Postocular spine on outer margin of postocular, with 8 spinous points; posterodorsal corner of postocular not expanded laterally. Transverse bump developed in front of occipital area (between bases of coronal spines), curved posteriorly in dorsal view. Parietal spine with 1 spinous point; base of parietal spine relatively long, diverging posteriorly, completely conjoined with base of nuchal spine; origin of parietal spine just behind of tip of coronal spine in dorsal view. Nuchal spine with 1 spinous point. Sphenotic with 8 (9 on right side) spines in 3 patches (2 short vertical ridges on right side), surrounding sensory canal. No postorbital spine or sensory canal. Pterotic spine serrated with 8 spinous points on relatively long base. Lower posttemporal spine with 2 (3 on right side) spinous points. No upper posttemporal spine. Spuracleithral spine with 1 spinous point on posterior end of long base.

No anterior lacrimal spine. Posterior lacrimal spine broad, plate-like, with 1 spinous point under skin. Lateral lacrimal ridge with 1 spine (2 on right side); ridge on dorsal articular process lacking spines (2 on right side). Suborbital ridge well serrated, spines aggregated into anterior [6 (8 on right side)] and posterior (8) groups; this ridge not conjoined with lateral lacrimal ridge. Suborbital pit shallow, poorly developed. Preopercular with 3 spines, uppermost spine longest, others both of similar shorter length, all spines directed posteriorly; upper and middle spines closer to each other than middle and lower spines; lowermost spine plate-like. One supplemental preopercular spine present. No exposed opercular spine.

Origin of first dorsal-fin spine above lower posttemporal spine; bases of first and second dorsal-fin spines closer to each other than those of subsequent adjacent spines; length of first spine 0.8 times that of second spine; sixth spine longest; lengths of fifth to seventh spines subequal; 12th spine shortest, its length 0.8 and 0.7 times those of antepenultimate and posteriormost spines, respectively; membrane of spinous portion of dorsal fin strongly incised. Dorsalfin soft rays all branched; third ray longest, its length less than that of longest dorsal-fin spine; posteriormost ray branched, with extremely low membrane extending to caudal peduncle. Origin of first anal-fin spine just below base of last dorsal-fin spine; third spine longest; first spine 0.6 times longer than second and third spines. Anal-fin soft rays all branched; second ray longest, its length subequal to that of longest dorsal-fin soft ray; posterior branch of last soft ray not joined by membrane to caudal peduncle. Pectoral fin long, tip of longest ray extending beyond a vertical through base of last anal-fin soft ray, but not reaching caudal-fin base; fifth ray longest; lengths of rays decreasing from fifth to ninth or tenth ray and increasing again toward 13th ray; middle 8 rays each branched into two; lower unbranched rays weakly thickened. Pelvic-fin soft rays all branched; third ray longest, longer than upper jaw; last ray joined by membrane to abdomen for less than one-fourth of its length; tip of longest ray just reaching anterior margin of anus when depressed. Caudal fin with 4 procurrent, 2 segmented unbranched, and 4 segmented branched rays in dorsal series; 3 procurrent, 2 segmented unbranched, and 5 segmented branched rays in ventral series; and moderately rounded posterior margin of fin. Caudal peduncle moderately deep, its depth 0.6 times caudal-peduncle length.

Color of preserved specimen. See also Fig. 2 . Head and body brownish-white without markings. Skin flap on uppermost preopercular spine base with brown pigmentation; other skin flaps and tentacles on head pale brownishwhite. Eye blackish-blue, without radial markings. Dorsal fin membrane translucent; each fin spine with a small brown blotch on middle to upper portion; soft-rayed portion of dorsal fin with about 33 small brown spots on rays. Anal fin membrane translucent, soft-rayed portion with about 17 small brown spots on rays, expressed as short lines basally. Pectoral fin membrane transparent, with about 6 transverse broad, brown bands (almost lost from posterior half of fin, but clearly apparent on inner surface). Pelvic fin membrane translucent, with 5 broad, brown bands. Caudal fin membrane transparent, with 34 brown spots on rays, expressed as short bars basally. Color in life and in fresh condition unknown.

Distribution. The species is currently known only from Makemo Atoll, Tuamotu Archipelago, French Polynesia, the holotype having been collected at 120 m depth off the atoll.

Etymology. The specific name tuamotuensis is derived from the name of the type locality of the species, the Tuamotu Archipelago.

Remarks. Among the valid species of Dendrochirus , D. tuamotuensis sp. nov. is uniquely characterized by having bilobed pectoral fins ( Fig. 3 ), those of the other species being rounded. Examinations of the available type specimens of the nominal species of Dendrochirus revealed D. tuamotuensis to be most similar to Pterois barberi Steindachner, 1900 , Dendrochirus hudsoni Jordan and Evermann, 1903, and Dendrochirus chloreus Jenkins, 1903 in having nine dorsalfin soft rays, five anal-fin soft rays, a relatively high count (more than 18) of pectoral-fin rays, fewer than two tentacles on the snout tip, and no large, ocellated spot on the softrayed portion of the dorsal fin. Two of these three nominal species, D. hudsoni and D. chloreus , were regarded as junior synonyms of P. barberi by Eschmeyer and Randall (1975) and Randall (2007); based on our examination, we concur.

Dendrochirus tuamotuensis is clearly distinguished from D. barberi in having more pectoral-fin rays [19 in D. tuamotuensis vs 17–18 (usually 18) in D. barberi ], and higher counts of spinous points on the suborbital [14 (16 on right side) vs 1–9] and pterotic spines (8 vs 1–5). Furthermore, D. tuamotuensis differs from D. barberi in having a slightly shallower, narrower body [body depth and width 35.4% SL and 18.6% SL, respectively, vs 34.0–43.9 (mean 39.2)% SL and 19.7–26.4 (22.7)% SL], a slightly shorter, narrower head [head length and width, 37.6% SL and 12.9% SL, respectively, vs 40.3–45.7 (42.9)% SL and 13.8–17.2 (15.4)% SL], a slightly smaller orbit diameter [12.9% SL vs 13.1–16.0 (14.2)% SL] and a slightly shorter postorbital length [15.3% SL vs 16.4–20.6 (18.5)% SL] ( Fig. 4 ; Table 1 ).

Comparative materials. Dendrochirus barberi: BPBM 24087, 6 specimens, 66.8–105.8 mm SL, northwest of Molokai Island, Hawaiian Islands, 21°15′N, 157°08′W, 124 m, shrimp trawl, National Marine Fisheries ServiceHonolulu Laboratory, 11 November 1968; BPBM 24373, 2, 93.2–110.3 mm SL, northwest of Molokai Island, Hawaiian Islands, 21°15′N, 157°08′W, 124 m, shrimp trawl, National Marine Fisheries Service Honolulu Laboratory, 28 November 1968; CAS-SU 7467, 2 paratypes of Dendrochirus chloreus , 34.8–36.8 mm SL, Honolulu, Oahu Island, Hawaiian Islands, United States Fish Commission, 1901; CAS-SU 23294, 5 paratypes of Dendrochirus hudsoni , 35.0– 54.8 mm SL, Honolulu, Oahu Island, Hawaiian Islands, RV Albatross, 1902; CAS-SU 23315, paratype of D. hudsoni , 71.9 mm, same data as CAS-SU 23294; FMNH 63582, 9, 24.1– 88.1 mm SL, Kahuku, Oahu Island, Hawaiian Islands, L. Woods et al., 21 April 1961; FMNH 63748, 3, 88.5–97.0 mm SL, Hawaiian Islands, John G. Shedd Aquarium, May 1937; MNHN 1975-981, 3 of 6, 33.8–102.8 mm SL, Kaneohe, Oahu Island, Hawaiian Islands, 21°30′N, 157°48′W, M. L. Bauchot et al., October 1974; UMB 164, holotype of Pterois barberi , 30.7 mm SL, Honolulu to Cape Horn, “Captain Barber”; USNM 50652, holotype of D. hudsoni , 33.8 mm SL, Waikiki, Oahu Island, Hawaiian Islands, United States Bureau of Fisheries, 1901; USNM 50701, holotype of D. chloreus , 96.5 mm SL, Honolulu, Oahu Island, Hawaiian Islands, O. P. Jenkins, 1889; USNM 109333, 2, 59.7–63.3 mm SL, reef at Mokuleia, Waialua, Oahu Island, Hawaiian Islands, O. Degener, 1938; USNM 109367, 2, 83.3–100.9 mm SL, Honolulu, Oahu Island, Hawaiian Islands, J. Thompson, 4 October 1939; USNM 140497, 4, 46.9–63.6 mm SL, Waimea Bay, Oahu Island, Hawaiian Islands, L. Schultz and V. Brock, 31 August 1947; USNM 265959, 3, 62.5–113.7 mm SL, Honolulu, Oahu Island, Hawaiian Islands, D. S. Jordan, 1902. Dendrochirus bellus: FMNH 58783, holotype of Brachirus bellus , 62.2 mm SL, Misaki (Kanagawa Prefecture), Japan, K. Aoki. Dendrochirus biocellatus: USNM 98894, holotype of Nemapterois biocellatus , 62.5 mm SL, 0.7 mile (ca. 1.3 km) off Jolo Light, Philippines (6°04′20″N, 120°59′20″E), 22 fathoms (ca. 40.2 m), 14 February 1908. Dendrochirus brachypterus: MNHN 6565, holotype of Pterois brachyptera , 70.1 mm SL, locality unknown. Dendrochirus zebra: CAS-SU 8673, 2 paratypes of Dendrochirus sausaulele Jordan and Seale, 1906, 56.6–95.4 mm SL, Apia, Samoa, D. S. Jordan and V. L. Kellogg, 1902; MNHN 6624, 2 syntypes of Pterois zebra , 33.2–37.3 mm SL, Ambon, Indonesia, J. R. C. Quoy and J. P. Gaimard; MNHN 6627, syntype of P. zebra , 48.2 mm SL, Mauritius, M. Maillard; MNHN 6629, syntype of P. zebra , 80.1 mm SL, Mauritius, M. Mathieu; MNHN 6545, syntype of P. zebra , 60.2 mm SL, same data as MNHN 6629; USNM 51760, holotype (90.0 mm SL) and paratype (70.7 mm SL) of D. sausaulele , same data as CAS-SU 8673.

Figures

Fig. 1. Lateral (top) and dorsal (bottom) views of head of Dendrochirus tuamotuensis sp. nov. (BPBM 37140, 57.4mm SL, holotype). Shaded areas indicate skin flaps. 1, nasal spine; 2, preocular spine; 3, supraocular spine; 4, postocular spine; 5, tympanic spine; 6, coronal spine; 7, parietal spine; 8, nuchal spine; 9, sphenotic spine; 10, pterotic spine; 11, lower posttemporal spine; 12, supracleithral spine; 13, preopercular spine; 14, supplemental preopercular spine; 15, suborbital ridge/spine; 16, lateral lacrimal ridge/spine; 17, posterior lacrimal spine. Scale bars 5mm.

Fig. 2. Holotype of Dendrochirus tuamotuensis sp. nov.(BPBM 37140, 57.4mm SL).

Fig. 3. Pectoral fin of Dendrochirus tuamotuensis sp. nov. (BPBM 37140, holotype, 57.4mm SL). Scale bar 5mm.

Fig. 4. Relationships of: A, body depth; B, body width; C, head length; D, head width; E, orbit diameter; F, postorbital length (all as % of standard length) to standard length (mm) in Dendrochirus tuamotuensis sp. nov.(star) and D. barberi (circles).