Sagittalarva inornata (Gilbert, 1890) Gilbert, 1890

Victor, Benjamin C., Alfaro, Michael E. & Sorenson, Laurie, 2013, Rediscovery of Sagittalarva inornata n. gen., n. comb. (Gilbert, 1890) (Perciformes: Labridae), a long-lost deepwater fish from the eastern Pacific Ocean: a case study of a forensic approach to taxonomy using DNA barcoding, Zootaxa 3669 (4), pp. 551-570 : 560-563

Sagittalarva inornata (Gilbert, 1890) , n. gen., n. comb.

( Figs. 5–9 )

Pseudojulis inornatus Gilbert, 1890: 67 (type locality, 22.87°N, 109.92°W; Cabo San Lucas, Baja California, Mexico).

Pseudojulis sp. Victor, 1987: 146, Fig. 1 (0.81°N, 86.23°W; 400 km E. of Galápagos).

Halichoeres cf. malpelo Beltrán-Leon & Herrera, 2000: 524, Fig. 181 (continental coastline of Colombia).

Halichoeres raisneri Baldwin & McCosker, 2001: 89 , figs. 4–5 (type locality, 1.39°N, 91.81°W; Wolf Island, Galápagos, Ecuador).

Halichoeres cf. raisneri Bussing & Lopez, 2004: 120 (5.57°N, 87.03°W; Cocos Island, Costa Rica).

Halichoeres sp. Bussing & Lopez, 2004: 121, figure (5.57°N, 87.03°W; Cocos Island, Costa Rica).

Material examined. USNM 44273, 73 mm SL, Cabo San Lucas, Baja California, Mexico, 22.87°N, 109.92°W, Albatross, dredge, 31 fathoms, 1 May 1888 (holotype of Pseudojulis inornatus ); USNM 357795, 90 mm SL, SE Wolf Island, Galápagos Islands, 1.39°N, 91.81°W, submersible JSL-II-sta. 3087, 115m, C. Baldwin & J.

Gomezjurado, 22 June 1998 (holotype of Halichoeres raisneri ); CAS 209810, 2: 39.8–78.8 mm SL, 1.39°N, 91.81°W, submersible JSL-II-sta. 3086, 114– 125m, C. Baldwin & J. McCosker, 22 June 1998 (paratypes of Halichoeres raisneri ); SIO 65-250, 106 mm SL, Isla Cerralvo Channel, Baja California, Mexico, 24.19°N, 109.99°W, Horizon, trawl, up to 46 fathoms, 2 July 1965; SIO 07– 34, 162 mm SL, Gordo Bank, San Jose del Cabo, Baja California, Mexico, 23.02°N, 109.50°W, hook and line, 50–100m, John Snow, 15 February 2007; SIO 07- 94, 136 mm SL, San Luis Canyon, San Jose del Cabo, Baja California, Mexico 23.05°N, 109.40°W, hook and line, 50– 100m, John Snow, 21 July 2007; SIO 11-386, 31: 7.0–14.0 mm SL, open ocean 400 km E. of Galápagos Islands, 0.81°N, 86.23°W, plankton net, 0–100m, B. Victor, 10 March 1985.

Diagnosis. Dorsal rays IX,12; anal rays III,12; pectoral rays 13 (12 plus uppermost rudimentary ray); lateralline continuous, inclined sharply downward below soft portion of dorsal fin, the pored scales 27, canals on scales with a single pore; head naked except for a set of small scales on each side of nape forward of the dorsal-fin origin; scales on thorax much smaller than body scales; jaws with a single pair of enlarged canine teeth at the front of the upper jaw (one tooth per side) and a single pair at the front of the lower jaw (one tooth per side) which fit between the upper pair when the mouth is closed; teeth behind enlarged canines in a regular row of caniniform to conical teeth; no posterior canine at the corner of the mouth; posterior half of upper lip with a dorsal fleshy flap, variably developed; 10+6 gill rakers, larger ones serrated and branched; snout long and pointed, snout length 3.3–3.4 in HL for fish over 70 mm SL (3.36 in holotype); body slender, depth of body 4.6–4.7 in SL for fish over 70 mm SL (4.57 in holotype, “depth 5 2/ 3 in length” in Gilbert (1890) must refer to TL); body very compressed, body width 9.0- 10.5% SL; dorsal-fin spines pungent, first spine shortest, subsequent spines and rays progressively longer; caudal fin only slightly rounded.

Mid to late-stage larvae (7–14 mm SL) slender, flattened, and dart-shaped with marked horizontal symmetry (symmetrical above and below the lateral midline); forehead low and straight; mouth small, terminal, and at the level of the lateral midline; snout long and sharply pointed; melanophore pigment limited to the tip of the upper and lower jaws and a few small melanophores along the edge of the caudal-fin and posterior dorsal and anal-fin membranes ( Fig. 3 ).

Description. Dorsal rays IX,12; anal rays III,12; all dorsal and anal rays branched, the last to base; pectoral rays 13 (12 plus uppermost rudimentary ray); pelvic rays I,5; principal caudal rays 14, median 12 branched, upper procurrent rays 6, lower procurrent rays 5, last procurrent ray segmented; lateral-line continuous, inclined sharply downward below soft portion of dorsal fin, the pored scales 26 plus one pored scale on caudal fin base; canals on scales with a single pore; gill rakers 10 on lower limb including angle, 6 on upper limb, larger gill rakers serrated and branched, some antler-like; branchiostegal rays 5; vertebrae 25.

Body proportions as % of SL for 162 mm male (136 mm SL male in parentheses). Body long and slim, maximum body depth 21.6 (21.3)% or 4.6 in SL (4.7); body very compressed, width 10.5 (9.0)% or 2.1 in depth (2.4); head length 31.5 (31.1)% or 3.2 in SL (3.2); snout long, length 9.6 (9.0)% or 3.3 in HL (3.4); orbit diameter 5.6 (5.1)% or 5.7 in HL (6.0); interorbital width 5.6 (4.7)% or 5.7 in HL (6.6); caudal peduncle narrow, depth 10.5 (11.8)% or 3.0 in HL (2.6); caudal-peduncle length 11.7 (11.8)% or 2.7 in HL (2.6).

Mouth small, terminal, oblique at about 45 degrees, upper-jaw length 8.0 (7.9)% or 3.9 in HL (3.9); jaws with a single pair of enlarged canine teeth at the front of the upper jaw (one tooth per side) and a single pair at the front of the lower jaw (one tooth per side) which fit between the upper pair when the mouth is closed; teeth behind enlarged canines in a regular row of 10-20 caniniform to conical teeth in each quadrant; no posterior canine at the corner of the mouth; pharyngeal dentition described in Baldwin and McCosker (2001); posterior half of upper lip with a dorsal fleshy flap ( Fig. 6 ), variably developed on smaller males and females, lower lip with a curved labial flap; preopercular margin free and smooth on the vertical portion from the lowest blue cheek stripe down and on the horizontal portion forward to a level in front of the eye; a single line of suborbital pores, 7 in semicircle from below posterior nostril to behind upper-pupil level. Scales cycloid and large, head naked but smaller scales extending forward of the dorsal fin origin and thorax with progressively smaller scales.

Origin of dorsal fin above first lateral-line scale, predorsal length 26.5 (23.5)% or 3.8 in SL (4.3); dorsal-fin spines slender but pungent, progressively longer, first spine 6.4%, second 7.0%, third 7.3%, last 7.9%; longest dorsalfin ray 10.5%; dorsal-fin base length 59.9 (66.2)%; preanal length 54.3 (52.9)% or 1.8 in SL (1.9); first anal-fin spine slender and short 3.7%, second 6.2%, third 7.6%; longest anal-fin ray 11.0%; anal-fin base length 33.9 (34.6)%; caudal fin very slightly rounded, length 16.0 (16.9)% or 2.0 in HL (1.8); third pectoral ray longest 16.7 (18.4)% or 1.9 in HL (1.7); pelvic fins long 19.1 (17.6)% or 1.7 in HL (1.8); prepelvic length 27.8 (28.7)% or 3.6 in SL (3.5).

Color in life of male primarily salmon pink to orange with bright blue stripes ( Fig. 5 ). The stripes comprise a mid-lateral blue line along the body, starting behind the head, curving up along the pectoral-fin base then running straight to the caudal-fin base; a broken or partial blue stripe along the lower lateral body; a blue stripe down the sagittal midline of the head; and three blue stripes across each side of the head: one behind the upper eye running back to below the anterior spinous dorsal fin, a second rearward from the upper jaw passing interrupted at the lower rim of the orbit and curving down across the operculum to meet the upper edge of the pectoral fin base, and the lowest from just behind the corner of the jaw across the lower operculum. Similar blue stripes run along the dorsal and anal fins about mid-way out on the membranes and, to a lesser degree, along the edge of the membranes. There are lighter contrasting stripes of light pinkish yellow running above the blue stripe on the snout and operculum and continuing above and below the mid-lateral blue line (more obvious in females, especially underwater photos).

There is a prominent contrasting black-to-dark-brown ribbon along the outer part of the dorsal fin as well as a sharp black edge to the caudal fin, that notably extends forward along the edges of the upper and lower tips of the tail. The caudal fin is bright orange with three thin blue-white bars, the last highlighting the black fin edge. There is a small dark spot on the dorsal midline of the body just after the base of the last dorsal fin ray.

Based on the color photograph in Baldwin and McCosker (2001), females have the same basic marking pattern, but without the contrasting black markings. The blue stripes are less intense, and appear pinkish blue and are adjacent to bright orange-yellow background stripes that are more distinct than on the males. In underwater photographs, the blue or pink stripes are mostly light streaks and the yellow stripes are intense ( Fig. 7 ). The stripes are broken by five pale indistinct bars producing a pattern of stripes and bars on living fish ( Fig. 7 and 8 ), but not obvious on dead or preserved specimens.

Juveniles in life have the same basic stripe pattern on a light background but with the upper-body dark stripe more contrasting. There is a prominent black spot at the base of the mid-portion of the soft dorsal fin that stands out in underwater videos ( Fig. 8 ). The juveniles also show the five light bars and the upper-body dark stripes from each side meet at the end of the dorsal fin followed by the last light bar, highlighting the junction as a dark blotch.

Color of male in alcohol pale yellow-brown with the blue lines mostly grey and outlined in dark and the black markings remaining prominent. Notably, there is a small but distinct dark spot on the body just behind the insertion of the last dorsal-fin ray. Females have no distinctive markings in preservative, but smaller individuals show the dark spot on the base of the fifth dorsal-fin soft ray (Baldwin & McCosker 2001).

Mid to late-stage larvae (7–14 mm SL) slender, flattened, and dart-shaped with marked horizontal symmetry (symmetrical above and below the lateral midline); forehead low and straight; mouth small, terminal, and at the level of the lateral midline; snout long and sharply pointed; melanophore pigment limited to the tip of the upper and lower jaws and a few small melanophores along the edge of the caudal-fin and posterior dorsal and anal-fin membranes ( Fig. 3 ).

Figures

FIGURE 1. Radiograph of the head of the holotype of Sagittalarva inornata (USNM 44273) showing a single pair of enlarged canines at the front of the upper and lower jaws followed by rows of caniniform to coniform teeth, courtesy Sandra Raredon, USNM.

FIGURE 3. Larval labrids of the eastern Pacific Ocean: from top, Sagittalarva inornata 11.6 mm SL & 8.3 mm SL, Halichoeres 13.1 mm SL, Thalassoma 10.2 mm SL (identified by DNA-barcode matching).

FIGURE 5. Sagittalarva inornata, male, 136 mm SL, SIO 07 - 94, photograph by John Snow.

FIGURE 6. Upper lip flap on male Sagittalarva inornata, 136 mm SL, SIO 07 - 94.

FIGURE 7. Underwater photograph of female S. inornata in Baja California from videos by Octavio Aburto-Oropeza and Brad Erisman.

FIGURE 8. Underwater photograph of juvenile S. inornata in Baja California from videos by Octavio Aburto-Oropeza and Brad Erisman.

FIGURE 9. Photograph and radiograph of the holotype of Sagittalarva inornata, 73 mm SL, USNM 44273, courtesy Sandra Raredon, USNM.