Upeneus stenopsis, Uiblein, Franz & Mcgrouther, Mark, 2012

Uiblein, Franz & Mcgrouther, Mark, 2012, A new deep-water goatfish of the genus Upeneus (Mullidae) from northern Australia and the Philippines, with a taxonomic account of U. subvittatus and remarks on U. mascareinsis, Zootaxa 3550, pp. 61-70 : 63-66

Upeneus stenopsis n. sp.

Narrow-tail goatfish

( Figs. 1–2 ; Table 1)

Holotype. AMS I.20918-017, 131 mm, NE Australia, Queensland, Coral Sea, off Raine Island, 11° 35' S, 144° 02' E, 270–275 m, prawn trawl.

Paratypes. 3 specimens (101–112 mm) from northern Australia and the Philippines. AMS I.21628-001, 108 mm, Northern Territory, Timor Sea, 09° 46' S, 128° 57' E, 165–190 m, bottom trawl; MNHN 2012-0212, 112 mm, Philippines, off Quezon Island, 13°58'59'' N, 120°18'00'' E, 186–187 m, beam trawl; MNHN 1984-0802, 101 mm, same station data.

Non-type. CAS 33367, 71 mm (juvenile), Philippines, Quezon Island, Catanauan, Sandoval Point, 127– 142 m.

Diagnosis. Dorsal fins VIII + 9; pectoral fins 15 or 16; gill rakers 7–8 + 18–20 = 25–28; measurements in % SL: body depth at first dorsal-fin origin 22–25; body depth at anus 18–21; caudal-peduncle depth 7.4–7.8; maximum head depth 22–23; head depth through eye 18–19; head length 33–34; orbit length 9.2–9.9; upper jaw length 14–15; barbel length 21–22; caudal-fin length 26–28; anal-fin height 15–16; pelvic-fin length 18–19; pectoral-fin length 23–25; first dorsal-fin height 20–23; second dorsal-fin height 14–16; total number of oblique caudal-fin bars 7–9, colour of bars changing from pale brown proximally to dark brown towards rear caudal-fin margin; 4–5 dark bars on upper caudal-fin lobe (including one bar close to rear end of lateral line), slightly increasing in width distally; 3–4 bars on lower caudal-fin lobe, of similar width as white interspaces between bars; first dorsal-fin tip black; caudal-fin bars and black dorsal-fin tip retained on preserved fish; barbels white; no lateral body stripes; head and body silvery laterally and reddish dorsally, belly and ventral side of peduncle white; preserved fish dorsally or entirely pale brown or brown, with ventral part of body and head covered by white or silvery pigment.

Description. Measurements in % SL and counts are given in Table 1; morphometric data as ratios of SL for holotype, data for paratypes in brackets: body moderately deep, its depth at first dorsal-fin origin 4.1[3.9–4.5]; body depth at anal-fin origin 5.4[4.8–5.4]; head depth through eye 5.2[5.2–5.6]; head length 2.9[3.0], clearly longer than maximum depth of body and caudal-fin length (3.6[3.6–3.8]); height of second dorsal fin 7.0[6.1–6.3], clearly less than barbel length (4.6[4.7–5.0]); pectoral-fin length 4.0[4.1–4.4], longer than pelvic-fin length (5.3[5.2–5.7]); orbit length 10[10–11], larger than caudal-peduncle depth (13[13]).

Fresh colour (based on holotype; Figure 1 a): Head and anterior part of body silvery laterally, the posterior and dorsal third of body as well as the dorsal head margin starting from upper jaw reddish; belly to ventral caudal peduncle white; no lateral body stripes; barbels white; both dorsal fins hyaline at base with white rays overlain by two horizontal pale red stripes and black tips (only the spiny dorsal-fin tip well visible in photograph of holotype); paired fins and anal fin hyaline, caudal fin with 9 oblique bars (the two distal-most bars covering the fin tips); 5 bars (including one bar close to rear end of lateral line) on upper lobe, 4 bars on lower lobe, with hyaline-whitish interspaces between bars; the five anterior-most caudal-fin bars changing from pale brown proximally to dark brown at rear caudal-fin margin; the distal-most bars (including fin tip) on lower caudal-fin lobe entirely dark brown; the bars on the upper caudal-fin lobe slightly increasing in width distally, the interspaces of lesser width as interspaces on lower lobe.

Preserved colour: Head and body uniformly brown in holotype with white pigmentation patches behind jaws, on opercle, ventrally from belly to caudal peduncle, and some tiny white markings along lateral line at mid body; first dorsal-fin tip and caudal-fin bar pigmentation partly retained at or close to distal fin margins; paratypes with large whitish or silvery patches on head below eye and/or surrounding the lower half of orbit, and on posterior opercle (reduced on preopercle); Body entirely whitish or silvery at ventral side, brown dorsally, with dark pigmentation on both dorsal-fin tips, and bars on lower caudal-fin lobe well retained, much weaker on upper lobe (upper caudal-fin lobe almost entirely broken in one specimen).

Distribution. N to NE Australia; Quezon, Philippines; first record of a deep-water goatfish of the genus Upeneus for the Pacific.

Etymology. The name “ stenopsis ” derives from the greek word “stenos”, meaning “narrow”, to refer to the rather narrow (both in depth and width) caudal peduncle of Upeneus stenopsis n. sp.

Comparisons (see also Table 1): Upeneus stenopsis n. sp. differs from all other congeneric species by its thinner caudal peduncle (peduncle depth and width in combination) and from the most closely related and/or cooccurring species of the vittatus group as follows: from U. davidaromi by lesser body depth (body depth at dorsalfin origin 22–25 vs 24–28 %SL; body depth at anal-fin origin 18–21 vs 20–23 %SL), shallower head (maximum head depth 22–23 vs 24–27 %SL; head depth through eye 18–19 vs 20–24 %SL), and shorter caudal fin (caudal-fin length 26–28 vs 28–30 %SL); from U. mascareinsis in shorter interdorsal distance (12–15 vs 15–18 %SL), longer pectoral fins (pectoral-fin length 23–25 vs 21–24 %SL), and lower number of gill rakers (25–28 vs 27–30 total number of gill rakers); from U. subvittatus in lesser body depth (body depth at dorsal-fin origin 22–25 vs 25–28 %SL; body depth at anal-fin origin 18–21 vs 22–23 %SL), larger eyes (orbit length 9.2–9.9 vs 7.8–8.8 %SL), and shorter interdorsal distance (12–15 vs 14–18 %SL); and from U. vittatus in lesser body depth (body depth at dorsalfin origin 22–25 vs 24–30 %SL; body depth at anal-fin origin 18–21 vs 21–24 %SL), longer head (head length 33–34 vs 29–32 %SL, larger eyes (orbit length 9.2–9.9 vs 6.6–8.8 %SL), longer jaws (upper-jaw length 14–15 vs 11–13 %SL, lower-jaw length (13–14 vs 11–12 %SL), longer barbels (barbel length 20–22 vs 16–21 %SL), lesser first dorsal-fin height (20–23 vs 22–28 %SL), lower caudal-fin bars and white interspaces not varying in width, first dorsal black tip smaller, and lateral body stripes absent.

Remarks. Upeneus stenopsis n. sp. shares with the three most closely related species U. davidaromi , U. mascareinsis , and U. subvittatus the following features: no lateral body stripes in life, a shallow caudal peduncle, and a long head with long jaws and large eyes. Sufficient distinction among those species is reached when comparing the following characters in combination ( Fig. 2 ): Number of gill rakers on lower limb, body depth at anal-fin origin, caudal-peduncle depth and width, and maximum head depth. While U. subvittatus occurs above 120 m depth, the other three species can all be characterized as lower-shelf and upper-slope dwellers, occurring mostly below 100 m depth.

The single juvenile specimen from Quezon largely overlaps in most morphometric and meristic characters with the four adult U. stenopsis n. sp. (Table 1, Fig. 2 ) and hence has been assigned to this species. Among the few minor deviations (Table 1, Fig. 2 ) the shallower head through eye, the smaller orbit, and the shorter jaws in the juvenile may reflect developmental changes. Other differences like the wider caudal peduncle (Table 1, Fig. 2 ) will need further studies to understand the overall intraspecific variability of this character.

Among the four juveniles of U. mascareinsis one specimen (SAIAB 82328) was earlier referred to as cf. mascareinsis in Uiblein and Heemstra (2010). Here, the full assignment to this species is based on the documented co-occurrence of 6 adults (> 79 mm SL) with 3 juveniles at two collecting stations off La Reunion (MNHN 1965- 79, RMNH 24949), the close overlap in geographical and depth distribution, the general similarity among the four juveniles, and the consistency of deviations in morphometric but not meristic characters from adult conspecifics. The major deviations are a shallower body, a smaller head with shorter jaws, shorter barbels, and shorter anal and paired fins in the four juvenile U. mascareinsis compared to the adults (Table 1, Fig. 2 ). The eyes are only smaller in the initial stages of the ontogeny ( Fig. 2 ).

Upeneus stenopsis n. sp. attains 13 cm SL; depth range 127– 275 m.

Figures

FIGURE 1. (a) Upeneus stenopsis, AMS I. 20918 - 017, 13.1 cm SL, NE Australia (D. F. Hoese); (b) U. davidaromi, SL 16.5 cm, Gulf of Aqaba (J. E. Randall), (c) U. mascareinsis, SAIAB 81951, SL 16.2 cm, Mozambique (P. C. Heemstra), (d) U. subvittatus, BPBM 32266, SL 20.5 cm, Moluccas, Indonesia (J. E. Randall); (e) U. subvittatus, MZB PB 389, SL 16.6 cm, Java, Indonesia (W. White); (f) U. vittatus, CSIRO KD 395, SL 14.1 cm, Bali, Indonesia (W. White). The photographs of U. stenopsis and U. vittatus are shown mirror-inverted in order to facilitate comparison.

FIGURE 2. Relationships among morphometric and meristic characters in four closely related species of the vittatu s group, Upeneus davidaromi, U. mascareinsis, U. stenopsis n. sp., and U. subvittatus. Specimens <80 mm SL are distinguished as juveniles by crossed symbols.