Pseudochromis rutilus, Gill, Anthony C., Allen, Gerald R. & Erdmann, Mark, 2012

Gill, Anthony C., Allen, Gerald R. & Erdmann, Mark, 2012, Two new dottyback species of the genus Pseudochromis from southern Indonesia (Teleostei: Pseudochromidae), Zootaxa 3161, pp. 53-60 : 58-59

Pseudochromis rutilus sp. nov.

Red-gold Dottyback

Figure 4 , Table 1

Holotype. MZB 20568, 55.0 mm SL, Indonesia, Nusa Penida, Buyuk (08°40’S 115°33’E), 65–70 m, M.V. Erdmann, 25 November 2008 (field number NP-08-12A).

Diagnosis. A species of Pseudochromis with the following combination of characters: dorsal-fin rays III,26; anal-fin rays III,14; circumpeduncular scales 16; dorsal-fin origin to pelvic-fin origin 34.7 % SL; third anal-fin spine 7.1 % SL.

Description (based on the holotype). Dorsal-fin rays III,26, all segmented rays branched; anal-fin rays III,14, all segmented rays branched; pectoral-fin rays 18/18; upper procurrent caudal-fin rays 6; lower procurrent caudal-fin rays 6; total caudal-fin rays 29; scales in lateral series 32/34; anterior lateral-line scales 24/26; anterior lateral line terminating beneath segmented dorsal-fin ray 19/20; posterior lateral-line scales 8 + 1/7 + 1; scales between lateral lines 3/3; horizontal scale rows above anal-fin origin 13 + 1 + 3/14 + 1 + 3; circumpeduncular scales 16; predorsal scales 25; scales behind eye 3; scales to preopercular angle 5; gill rakers 5 + 12 = 17; pseudobranch filaments 11; circumorbital pores 30/28; preopercular pores 10/9; dentary pores 4/4; posterior interorbital pores 2.

Lower lip incomplete (interrupted at symphysis); dorsal and anal fins without scale sheaths, though with intermittent scales overlapping fin bases; predorsal scales extending anteriorly to midway between anterior and posterior nostrils; opercle with 4–5 indistinct serrations; teeth of outer ceratobranchial-1 gill rakers well-developed on distal halves of rakers only; anterior dorsal-fin pterygiophore formula S/S/S + 3/1 + 1/1/1/1/1/1 + 1/1/1/1 + 1; dorsal-fin spines stout and pungent; anterior anal-fin pterygiophore formula 3/1 + 1/1/1 + 1; anal-fin spines stout and pungent, second spine stouter than third; pelvic-fin spine moderately stout and pungent; second segmented pelvic-fin ray longest; caudal fin rounded; vertebrae 10 + 16; epineurals 14; epurals 3.

Upper jaw with 2 pairs of curved, enlarged caniniform teeth anteriorly, and 6 (at symphysis) to 3 (on sides of jaw) inner rows of small conical teeth, outermost of rows of conical teeth much larger and more curved than inner rows; lower jaw with 3 pairs of curved, enlarged caniniform teeth anteriorly, and 5 (at symphysis) to 1 (on sides of jaw) inner rows of small conical teeth, teeth on middle of jaw slightly larger and curved; vomer with 1–2 rows of small conical teeth, forming chevron; palatines with 1–3 rows of small conical teeth arranged in elongate, suboval patch, anterior part of tooth patch more-or-less contiguous with posterolateral arm of vomerine tooth patch; ectopterygoid edentate; tongue moderately pointed and edentate.

As percentage of SL: head length 24.9; orbit diameter 9.5; snout length 6.9; fleshy interorbital width 6.5; bony interorbital width 4.7; body width 14.7; snout tip to posterior tip of retroarticular bone 15.3; predorsal length 35.3; prepelvic length 34.0; posterior tip of retroarticular bone to pelvic-fin origin 19.6; dorsal-fin origin to pelvic-fin origin 34.7; dorsal-fin origin to middle dorsal-fin ray 39.1; dorsal-fin origin to anal-fin origin 47.6; pelvic-fin origin to anal-fin origin 30.0; middle dorsal-fin ray to dorsal-fin termination 24.0; middle dorsal-fin ray to anal-fin origin 33.3; anal-fin origin to dorsal-fin termination 36.7; anal-fin base length 26.4; dorsal-fin termination to anal-fin termination 18.7; dorsal-fin termination to caudal peduncle dorsal edge 10.2; dorsal-fin termination to caudal peduncle ventral edge 20.4; anal-fin termination to caudal peduncle dorsal edge 23.6; anal-fin termination to caudal peduncle ventral edge 12.4; first dorsal-fin spine 3.1; second dorsal-fin spine 6.5; third dorsal-fin spine 8.5; first segmented dorsal-fin ray 13.3; fourth last segmented dorsal-fin ray 17.6; first anal-fin spine 2.2; second anal-fin spine 5.3; third anal-fin spine 7.1; first segmented anal-fin ray 11.2; fourth last segmented anal-fin ray 17.3; third pectoral-fin ray 17.5; pelvic-fin spine 12.2; second segmented pelvic-fin ray 26.9; caudal-fin length 28.2.

Live coloration (based on a photograph of the holotype): Head purplish to reddish brown, becoming pale orange ventrally; orbital rim narrowly bright yellow, bordered around posterior and ventral edge with blue curved bar, this extending to middle of upper lip, then along ventral edge of first infraorbital to snout; cheeks tinged with pale blue; opercular flap with indistinct dusky grey spot; anterior portion of operculum pale blue with short purplish red horizontal lines; iris purplish brown dorsally, yellow ventrally, with bright blue sub-oval ring around pupil; body purplish to reddish brown dorsally, bright orange-yellow to gold on flanks, becoming pale pink to pale purple ventrally; scales of anterior lateral line and next 4–5 scale rows below each with large gold spot, these becoming less distinct and grading into background coloration on mid-sides of body and caudal peduncle; scales of nape and body above anterior lateral line each with indistinct yellow basal spot; dorsal fin purple basally, the remainder of fin pinkish hyaline with narrow purple margin; fin rays bright yellow, with large bright yellow spot at the base of each ray; anal fin similar to dorsal fin, except with spots at base of each fin ray pale pink, and with row of bright yellow spots along distal edge of purple basal stripe; caudal fin bright yellow, greyish yellow on central part of fin base, with distal third of fin abruptly pinkish hyaline; pectoral fins pinkish hyaline, bright yellow on fin base; pelvic fins pinkish hyaline, pale mauve anteriorly and distally.

Preserved coloration: pattern similar to live coloration, purplish to reddish brown, blue and grey markings on head, body and fins becoming greyish brown; lower part of head and body pale yellow; orange, gold and yellow spots conspicuous on body, becoming pale yellow.

Habitat and distribution. Known only from the holotype, this species was observed and collected at 70 m depth on a current-swept, steep slope on the north face of Nusa Penida island in the Lombok Strait off Bali. Though only one specimen was collected, several individuals were observed in the near vicinity, all of them darting under low, rocky overhangs and larger coral rubble pieces on this current-swept, low-relief slope.

Comparisons. Pseudochromis rutilus is ambiguous at couplet 50 of Gill’s (2004) key to Pseudochromis species, having the relatively deep body of 50a (P. f o w l e r i Herre 1934), but the relatively short anal-spine three of 50b ( P. andamanensis Lubbock 1980 , P. aurulentus Gill & Randall 1998 , P. flavopunctatus Gill & Randall 1998 , P. litus Gill & Randall 1998 , P. marshallensis Schultz 1953 , P. p y l e i Randall & McCosker 1989, and P. reticulatus Gill & Woodland 1992 ). Thus, these two characters in combination (dorsal-fin origin to pelvic-fin origin 34.7% SL; third anal-fin spine 7.1 % SL) are useful to distinguish P. rutilus from species at couplet 50. It is further distinguished from P. fo w le r i in having III,26 dorsal-fin rays (versus III,23–25), 25 predorsal scales (versus 13–18), which extend anteriorly to midway between the anterior and posterior nostrils (versus to point ranging from vicinity of anterior AIO pores to midway between posterior nasal pores and posterior nostrils), and a rounded caudal fin (versus emarginate). Pseudochromis oligochrysus also falls beyond couplet 50 of Gill’s key. It is readily distinguished from P. rutilus in having more segmented anal-fin rays (16 versus 14).

Remarks. The specific epithet is from the Latin, meaning reddish gold, and alludes to the purplish red and yellow to gold live coloration.

Figures

FIGURE 4. Pseudochromis rutilus, ZMB 20568, holotype, 55.0 mm SL, Buyuk, Nusa Penida, Indonesia (photo by M. V. Erdmann).