Jaydia erythrophthalma, Gon, Ofer, Liao, Yun-Chih & Kwang-Tsao, Shao, 2015

Gon, Ofer, Liao, Yun-Chih & Kwang-Tsao, Shao, 2015, A new species of the cardinalfish genus Jaydia (Teleostei: Apogonidae) from the Philippines, Zootaxa 3980 (2), pp. 286-292 : 287-291

Jaydia erythrophthalma n. sp.

Figures 2a, b ; Table 1

Holotype. PNM 15192 (ex-ASIZP 68202), 50.5 mm, male, Philippines, Luzon, Aurora Province, west of Cape San Ildefonso, 16.0445°N, 121.922°E, 194–203 m, beam trawl, MV DA-BFAR, Y.-C. Liao & K.-T. Shao, 1 June 2007. Paratypes. ASIZP 68318, 2: 56.9–58.6 mm, females, Philippines, Luzon, Aurora Province, southwest of Cape San Ildefonso, 15.9745°N, 121.84283°E, 364–469 m, otter trawl, MV DA-BFAR, Y.-C. Liao & K.-T. Shao, 2 June 2007; CAS 236504, 2: 50.3–57.05 mm, females, Philippines, between Luzon and Mindoro islands, 13.886333°N, 120.0565°E, station HEPD 0 21, 132– 172 m, beam trawl, crew of MV DA-BFAR, 1 June 2011; CAS 236506, 12: 24.9–48.5 mm, Philippines, between Luzon and Mindoro islands, 13.885667°N, 120.129833°E, station HEPD 0 22, 115– 144 m, otter trawl, crew of MV DA-BFAR, 1 June 2011; SAIAB 200712, 2: 34.65–46.5 mm, female and male, respectively, and USNM 435707, 2: 34.9–41.2 mm, females, both lots originally part of CAS 236506.

Comparative material. Jaydia argyrogaster : WAM 25508–016, 51.1 mm; WAM 26188–022, 49.9 mm; WAM 26212–007, 47.8 mm, all from Western Australia; WAM 33093–001, 43.5 mm, West Papua, Indonesia; ZMA 101.075, 2: 34.4–46.3 mm, syntypes, Indonesia. Jaydia photogaster : material from New Guinea listed in Gon & Allen (1998).

Diagnosis. A species of Jaydia with reddish orange iris; usually eight first dorsal fin spines, eighth spine tiny; two series of dark spots (suffused with orange in life) on upper part of body of which anterior spots of upper series with paler centre; posterior preopercular edge with 5–14 small serrations and membranous, crenulated ventral edge.

Description. Proportional measurements of the holotype and selected paratypes are given in Table 1 . Data in parentheses refer to paratypes. First dorsal-fin spines 8 (7–8); second dorsal fin with 1 spine and 9 (8–9) soft rays; anal-fin rays II,8; last soft ray of dorsal and anal fins branched to base; pectoral-fin rays 15 (14–15), two upper and lowermost rays unbranched; pelvic-fin rays I,5, all soft rays branched; principal caudal-fin rays 17, upper and lowermost rays unbranched; upper and lower procurrent caudal rays 5 (5 on both sides or 6 dorsal and 5 ventral); total number of gill rakers 4 + 12 (3–4 + 10–14 = 14–18, usually 15–17); developed gill rakers 2 + 10 (1–2 + 8–10); gill rakers on ceratobranchial 8 (7–9, usually 7 or 8); median predorsal scales 3 (see Remarks below); branchiostegal rays 7; supraneurals 3. Light organ associated with intestine absent.

Body deep and compressed, its depth 2.7 (2.7–3.0) in SL and its width 2.1 (1.7–2.1) in depth; head length 2.3 (2.2–2.5) in SL; snout length 4.6 (4.2–5.2), eye diameter 3.5 (3.4–4.0), and interorbital space, slightly convex, 4.8 (4.3–4.9), all in head length.

Mouth terminal, oblique and large; maxilla reaching posteriorly to vertical at posterior edge of eye (to slightly behind eye in several paratypes); upper jaw length 2.0 (1.7–2.0) and lower jaw 1.7 (1.6–1.7) in head length; both jaws with polyserial band of villiform teeth; band of lower jaw tapering posteriorly; vomer with 3 (2–3) series of villiform teeth and palatines with few small teeth anteriorly (see Remarks for variation in paratypes).

Rear nostril oval, close in front of eye, at about level of centre of eye and its vertical diameter about 2.5 times in pupil diameter; anterior nostril round, slightly lower, at mid-distance between posterior nostril and tip of snout (excluding upper lip), with elevated posterolateral rim, its diameter about half longer axis of posterior nostril.

First infraorbital pore about as large as posterior nostril, its upper end directly below this nostril and its lower end close behind anterior nostril; second and third pores next to each other, on ventral of suborbital bone and open ventrally, second pore about 1.5 of third pore; first supraorbital pore somewhat larger than posterior nostril, close to tip of snout and with short skin flap that reaches tip of snout (excluding upper lip); second supraorbital pore slightly smaller than posterior nostril and medial to it; third supraorbital pore damaged (smaller than second pore, on edge of interorbital space at vertical through middle of eye in paratypes); edges of head canals perforated by small secondary pores.

Posterior preopercular edge armed with 14 (5–13) very small serrations mostly on lower part; ventral preopercular edge membranous and crenulated ( Fig. 2 e); preopercular ridge irregular around angle (smooth in several paratypes); exposed edge of posttemporal with 2 tiny serrations on left side and smooth on right side (smooth or with 1–4 serrations).

Body scales large, ctenoid and apparently easily shed; lateral line scales lost except for 2 at origin and 5 on caudal peduncle, about 24 to hypural plate based on count of scale pocket; roof of lateral line canal on each scale (when present) wide and with 2 dorsal and ventral pores.

Dorsal-fin origin over second lateral-line scale and slightly in front of vertical through upper pectoral-fin base; first dorsal spine 3.1 (2.3–3.2) in second spine; second dorsal spine 2.0 (1.5–2.0) in third spine and 4.9 (3.5–4.9) in head length; third dorsal spine 2.5 (2.2–2.7) and fourth dorsal spine 2.5 (2.3–2.7) both in head length; spine of second dorsal fin 3.5 (3.1–3.7) and longest dorsal soft ray, second or third ray, 1.95 (1.75–2.0) in head length; first anal spine 3.1 (2.5–3.2) in second spine; second anal spine 3.7 (3.05–4.0) and longest anal ray, second or third ray, 2.1 (1.8–2.1) both in head length; pectoral fin relatively long, 4.0 (4.0–4.6) in SL, reaching posteriorly over base of second anal-fin ray (over anal-fin origin to over base of third anal-fin ray); pelvic fins inserted in front of vertical through dorsal-fin origin, 4.0 (3.8–4.25) in SL, reaching posteriorly to about midway between anus and anal-fin origin (to genital papilla and to anal-fin origin in some paratypes); pelvic spine length 1.5 (1.5–1.7) in fin’s length; caudal fin slightly rounded, 3.5 (3.1–3.7) in SL.

Dorsal profile of head slightly convex, predorsal distance 2.3 (2.3–2.5), preanal distance 1.5 (1.4–1.7) and prepelvic distance 2.4 (2.5–2.7) in SL; caudal peduncle depth 1.7 (1.4–1.75) in its length, and the length 4.2 (4.1– 4.95) in SL.

Holotype Paratype Paratype Paratype Paratype Paratype Caudal fin length 28.3 32.1 29.9 Damaged 27.9 27.0 Colour of holotype after death ( Fig. 2a ): upper body white with orange hue, gradually shading to silvery white ventrally; two series of dark spots suffused in reddish orange; upper series of four spots with diffuse paler middle lined along lower edge of lateral line canal below dorsal fins; another smaller indistinct spot anteriorly on caudal peduncle; lower series with four spots along middle of body, arching upward anteriorly; first spot irregular nearly vertical elongate mark and second spot oval, both below first two spots of upper series; last two spots distinctly smaller, placed below last two spots of upper series. Scales on predorsal area, above lateral line, on caudal peduncle and below pectoral fin with dusky orange edge. Head yellowish, silvery ventrally; eye with bright reddish orange iris; two dark narrow stripes suffused with orange radiating from eye; one from its upper edge to posttemporal and another from lower edge almost to angle of preopercular ridge. Membrane between first three dorsal-fin spines with small dark dots; membrane between remaining spines of first dorsal fin with dark dots distally; second dorsal fin with wide yellowish green band of small dark dots extending diagonally from upper part of fin’s spine to base of its last ray; another, less distinct band apparently present higher up and separated from lower band by pale area with white dots; anal fin dusky orange, except last 2 or 3 rays, and pale base and distal edge; upper half of caudal fin greenish yellow, lower half reddish brown with lowermost rays reddish; pelvic and pectoral fins pale; pale areas in all fins, except caudal and pectoral, with white dots.

Colour in alcohol ( Fig. 2b ): body cream white to pale brown; snout and interorbital space with small dark dots; predorsal scales and scales above lateral line with dark edge; diagonal dark stripe from upper edge of eye to posttemporal usually present; two series of dark spots on upper part of body; first series, of 5–7 spots, runs along lower edge of lateral line canal, from behind posttemporal to anterior part of caudal peduncle; anterior 2 or 3 spots usually larger and with paler centre; lower series, of 4–6 spots of similar size to posterior upper series spots, runs along middle of body; lower series spots on caudal peduncle sometimes indistinct and vertically merged with upper series spots above them to form narrow bars of varying length and intensity that may reach ventral edge of peduncle. Membrane of first dorsal fin with dark spots distally; second dorsal fin pigmentation variable, changing from pale to one or two stripes made of small dark dots along middle section of fin, usually fading out anteriorly; posterior part of base of second dorsal and anal fins with varying amount of small dark dots; other fins pale. Peritoneum pale, except dark-dotted dorsal part; stomach and intestine, except straight section in front of anus, with small blackish dots.

Distribution. Jaydia erythrophthalma is currently known only from the Philippines, the type locality ( Fig. 1 ). The type specimens were collected at a depth range of 115– 469 m.

Etymology. This species is named erythrophthalma from the Greek for red (eruthros) eye (ophthalmos), an adjective treated as feminine.

RemarKs. One specimen (of 13 counted) had seven first dorsal-fin spines. The eighth dorsal spine of all specimens with such a spine was very small, sometimes barely exposed and undetectable without careful observation under magnification. One paratype had eight soft rays in the second dorsal fin. Variation in the number of pectoral-fin rays included one specimen with 14 rays on the left fin and two specimens with 14 rays on the right fin. All specimens lost most or all their scales; the count of median predorsal scales was based on scale pockets. The length of the second developed gill raker on the upper gill arch, when present, varied from almost as long as the first developed raker to about half the length of the latter. Lateral line scales seem to be larger than body scales above and below them. Most specimens had 1 or 2 series of small teeth on the palatines, but several, including the holotype, had only few teeth at the anterior end of these bones. Measured as a proportion of the head length, the third (2.51 + 0.17 SD) and the fourth (2.53 + 0.16 SD) dorsal-fin spines alternated as the longest spine, but with a practically identical mean they can be regarded as subequal.

The white dots on the dorsal, anal and pelvic fins of the holotype ( Fig. 2a ) are probably guanine deposits. On the first dorsal fin these white dots cover the entire membrane between the fourth and fifth spines; on the second dorsal fin they form two white bands, one immediately above the fin’s base and another above the first band of dark dots. In the preserved holotype the fins areas that show white dots are now clear making the dark-dotted areas of the fins more visible. A comparison of the dark pigmentation of the dorsal fins in all the type specimens revealed variation. In the first dorsal fin much of the dark dots are found on the membrane between the posterior spines. In the second dorsal fin of several specimens the dark dots form two stripes across the fin, similar to those observed in other species of Jaydia , albeit not as well-defined. These stripes are darkest at the end of the fin, gradually fading anteriorly ( Fig. 2 c).

We classify this species in the genus Jaydia with which it shares the character combination of reduced serration of the preopercular edges, rounded caudal fin, 1 or 2 developed gill rakers on the upper gill arch, usually smooth posttemporal, two dark stripes radiating from the eye and two dark stripes on second dorsal fin. We note that a first dorsal fin with eight spines, and a preopercle edge with a serrated posterior edge and a membranous, crenulated ventral edge have not been previously observed in this genus. Nevertheless, Gon (1997) recognized three species groups in Jaydia partly characterized by different preopercular edge conditions. Therefore, the presence of a fourth group cannot be ruled out.

Comparisons. Iwamoto and McCosker (2014) identified this species as Jaydia cf. poecilopterus . Indeed, the series of spots on the upper part of the body, the rounded caudal fin, the counts of gill rakers, the crenulated ventral preopercular edge, the pale peritoneum and the similarity in length between the third and fourth dorsal-fin spines do agree with J. poecilopterus as well as with other members of the Jaydia carinata group ( Gon, 1997). But the three members of this group do not have a serrated posterior preopercular edge, all have 7 spines in the first dorsal fin, 16 pectoral-fin rays and, as correctly pointed out by Iwamoto & McCosker (2014), their colour pattern is different. The colour pattern of Jaydia erythrophthalma more closely resembles that of J. argyrogaster , which has several series of similar but uniformly filled dark spots ( Fig. 2 d; Allen & Erdman, 2012: 382). Another species, J. photogaster , has dusky bars on the body in which the upper ends of the bars sometimes appear as a series of dark spots above the lateral line canal (see illustration in Gon & Allen, 1998). Jaydia argyrogaster and J. photogaster differ from J. erythrophthalma in having serrations on the posterior and ventral edges of the preopercle ( Fig. 2 f), both of which are ossified, and a dark-dotted peritoneum. They also lack orange pigmentation in their eyes or body ( Allen & Erdmann, 2012). These characters associate both species with the J. lineata group of Gon (1997). In addition, these two species share a unique intestinal light organ with a light diffuser organ that superficially resembles that of Siphamia species (see drawings and photos in Gon & Allen, 1998 and Allen & Erdmann, 2012, respectively), but is not known in any other apogonid species.

Figures

FIGURE 1. Map of southern Luzon, Philippines; squares accompanied by museum numbers indicate trawl stations in which type specimens were collected.

FIGURE 2. a, b) Jaydia erythrophthalma, PNM 15192, holotype, 50.5 mm, colour pattern after death and after preservation, respectively; c) Pigment pattern on the second dorsal fin of Jaydia erythrophthalma CAS 236506, 31.8 mm, paratype; d) Jaydia argyrogaster WAM 33093 – 001, 43.5 mm, West Papua, Indonesia; e) Lateral view of the ventral portion of the right preopercle of Jaydia erythrophthalma CAS 236504, 57.05 mm, paratype; arrows point to crenulated area of the ventral edge; f) Lateral view of the ventral portion of the left preopercle of Jaydia argyrogaster WAM 33093 – 001, 43.5 mm; arrows delineate the serrated part of the preopercle edge.

Tables

TABLE 1. Proportional measurements of selected type specimens of Jaydia erythrophthalma expressed as percentages of the standard length.

	ASIZP 68202	CAS 236506	CAS 236506	CAS 236504	ASIZP 68318	ASIZP 68318
Standard length (mm) Head length (mm) Body depth	50.5 22.25 37.2	34.9 14.8 36.4	46.5 19.85 34.4	50.3 21.1 35.3	56.9 23.75 35.3	58.6 23.85 36.35
Body width Head length Snout length	17.9 44.1 9.6	18.2 42.4 8.9	17.0 42.7 8.8	19.5 41.95 9.4	17.3 41.7 9.7	17.2 40.7 9.6
Eye diameter Interorbital width Upper jaw length	12.7 9.1 22.5	12.0 9.9 24.4	11.4 8.8 21.6	11.9 8.75 21.7	10.5 9.05 22.0	10.9 8.3 21.7
Lower jaw length Maxillary width First dorsal spine	26.4 6.3 2.9	26.8 6.6 4.0	26.0 6.2 4.2	25.25 6.1 3.8	26.0 6.85 3.3	25.8 6.7 3.7
Second dorsal spine Third dorsal spine Fourth dorsal spine	8.9 17.4 17.4	12.0 19.2 18.6	9.7 17.7 18.2	8.55 17.0 15.9	9.0 15.4 15.6	8.45 15.7 16.0