Pseudochromis lugubris, Gill, Anthony C. & Allen, Gerald R., 2004

Gill, Anthony C. & Allen, Gerald R., 2004, Pseudochromis lugubris and P. tonozukai, two new dottyback fish species from the Indo­Australian Archipelago (Perciformes: Pseudochromidae: Pseudochrominae), Zootaxa 604, pp. 1-12 : 2-6

Pseudochromis lugubris new species

Mournful Dottyback

( Figures 1–2 ; Table 1 )

Holotype: BPBM 36253, 38.4 mm SL, Papua New Guinea, Milne Bay, west of Wahawe Point, 10°16'S 150°42'42"E, cave in 6 m, rotenone, J.L. Earle, 13 December 1993.

Paratypes: AMS I.40685­001, 47.3 mm SL, Papua New Guinea, Louisiade Archipelago, Conflict Group, east end of Irai Island, 10°46'S 151°42'E, outer reef slope, coral and rock, 12–15 m, rotenone, G.R. Allen, 1 October 1997; BMNH 2001.3.8.1, 55.9 mm SL, collected with AMS I.40685­001; USNM 364533, 59.2 mm SL, collected with AMS I.40685­001; WAM P.31355­015, 3: 45.7–65.9 mm SL, collected with AMS I.40685­001.

Diagnosis. A species of Pseudochromis with the following combination of characters: dorsal­fin rays III,26–27; anal­fin rays III,14; scales in lateral series 48–50; and caudal fin truncate to emarginate, sometimes weakly trifurcate.

Description. Dorsal­fin rays III,26–27 (III,26), last 11–27 (11) segmented rays branched; anal­fin rays III,14, all segmented rays branched; pectoral­fin rays 15–18 (17/ 17); upper procurrent caudal­fin rays 7–8; lower procurrent caudal­fin rays 7; total caudalfin rays 31–32 (31); scales in lateral series 48–50 (49/50); anterior lateral­line scales 30– 38 (?/31); anterior lateral line terminating beneath segmented dorsal­fin ray 13–19 (?/15); posterior lateral­line scales 6–20 + 0–2 (6 + 1/6 + 1); scales between lateral lines 4–6 (?/5); horizontal scale rows above anal­fin origin 15–17 + 1 + 2–4 = 19–21 (16 + 1 + 3/16 + 1 + 3); circumpeduncular scales 20; predorsal scales 23–28 (26); scales behind eye 2–3 (3); scales to preopercular angle 4–6 (5); gill rakers 4–5 + 11–13 = 15–17 (4 + 13); pseudobranch filaments 10–11 (11); circumorbital pores 21–39 (21/21); preopercular pores 9–17 (10/9); dentary pores 4; posterior interorbital pores 1–2 (2).

Lower lip incomplete; dorsal and anal fins without distinct scale sheaths, although sometimes with scales intermittently overlapping fin bases; predorsal scales extending anteriorly to point ranging from posterior edge of AIO pores to mid AIO pores; opercle with 3–5 weakly to moderately developed serrations; teeth of outer ceratobranchial­1 gill rakers well developed on raker tips only; anterior dorsal­fin pterygiophore formula S*/S/S + 3/1 + 1/1/1/1/1 + 1*/1 (S/S/S + 3/1 + 1/1/1/1/1/1 + 1); dorsal­fin spines moderately stout and pungent; anterior anal­fin pterygiophore formula 3/1/1 + 1*/1 or 3/1 + 1/1/1 + 1* (3/1/ 1/1 + 1); anal­fin spines moderately stout and pungent, second spine much stouter than third; pelvic­fin spine moderately stout and pungent; second segmented pelvic­fin ray longest; caudal fin truncate to emarginate, sometimes with middle rays slightly produced (thus fin weakly trifurcate); vertebrae 10 + 16; epineurals 13–14 (14); epurals 3.

Upper jaw with 2–4 pairs of curved, enlarged caniniform teeth anteriorly, medial pair smallest, and 4–6 (at symphysis) to 2 or 3 (on sides of jaw) inner rows of small conical teeth; lower jaw with 1–3 pairs of curved, enlarged caniniform teeth anteriorly, the medial pair smallest, and 4 or 5 (at symphysis) to 1 (on sides of jaw) inner rows of small, conical teeth, teeth on middle of jaw larger and curved; vomer with 2 or 3 rows of small conical teeth, forming chevron; palatine with 1–3 rows of small conical teeth arranged in elongate, suboval patch, anterior part of the tooth patch more­or­less contiguous with posterolateral arm of vomerine tooth patch; ectopterygoid edentate; tongue moderately pointed and edentate.

As percentage of SL (based on 38.4­mm SL holotype and four paratypes, 47.3–65.9 mm SL): head length 22.5–26.3 (26.3); orbit diameter 7.7–9.4 (9.4); snout length 6.3–7.0 (7.0); fleshy interorbital width 4.7–5.5 (5.5); bony interorbital width 3.6–3.9 (3.9); body width 10.3–11.2 (11.2); snout tip to posterior tip of retroarticular bone 14.8–16.1; predorsal length 30.9–34.9 (34.9); prepelvic length 31.3–32.9 (32.3); posterior tip of retroarticular bone to pelvic­fin origin 18.2–20.9 (18.2); dorsal­fin origin to pelvic­fin origin 24.3– 25.5 (25.5); dorsal­fin origin to middle dorsal­fin ray 30.5–35.7 (30.5); dorsal­fin origin to anal­fin origin 39.8–41.7 (39.8); pelvic­fin origin to anal­fin origin 31.7–34.2 (33.9); middle dorsal­fin ray to dorsal­fin termination 23.3–24.9 (24.2); middle dorsal­fin ray to anal­fin origin 22.4–24.3 (22.9); anal­fin origin to dorsal­fin termination 29.7–33.7 (29.7); anal­fin base length 23.2–27.3 (23.2); dorsal­fin termination to anal­fin termination 14.1– 15.9 (14.1); dorsal­fin termination to caudal peduncle dorsal edge 10.8–12.3 (10.9); dorsal­fin termination to caudal peduncle ventral edge 17.3–18.5 (17.4); anal­fin termination to caudal peduncle dorsal edge 18.6–21.2 (18.8); anal­fin termination to caudal peduncle ventral edge 12.2–13.2 (12.2); first dorsal­fin spine 1.1–1.9 (1.8); second dorsal­fin spine 4.2–5.1 (4.7); third dorsal­fin spine 5.8–7.6 (7.6); first segmented dorsal­fin ray 11.0–13.5 (11.7); fourth last segmented dorsal­fin ray 14.4–17.1 (14.6); first anal­fin spine 1.8–2.7 (2.3); second anal­fin spine 5.8–7.0 (7.0); third anal­fin spine 6.8–7.9 (7.8); first segmented anal­fin ray 11.7–12.3 (11.7); fourth last segmented anal­fin ray 13.5–15.6 (13.5); third pectoral­fin ray 13.5–16.0 (14.3); pelvic­fin spine 7.7–9.1 (9.1); second segmented pelvic­fin ray 19.8–25.8 (20.1); caudal­fin length 21.9–25.0 (21.9).

Live coloration (based on field notes taken by J.E. Randall from the holotype when freshly dead and underwater photographs taken by S.W. Michael at Milne Bay, Papua New Guinea; Fig. 1 ). Head olive to reddish or greenish grey, becoming purplish grey on upper operculum, and purple to blue on ventral part of head and lips; short dark grey to black bar on midposterior part of orbital rim, narrowly edged posteriorly with bright blue; anterior edge of dark bar and posteroventral edge of orbit bright orange, this coloration usually expanded ventrally as triangular or tear­drop shaped mark beneath middle of eye; iris brown to orange, with bright blue suboval ring around pupil; body greenish to brownish grey, darker posteriorly, becoming pale grey­brown to golden brown on abdomen and lower sides; scales of body and nape darker on posterior edges, giving slight reticulated pattern; caudal peduncle with two broad, though indistinct, bluish grey stripes, extending along dorsal and ventral margins of peduncle; dorsal and anal fins brown to green basally, becoming greyish to reddish hyaline distally, with indistint narrow blue stripes on distal two­thirds of fins; caudal fin dark greenish to bluish grey basally, becoming pinkish to bluish hyaline distally, with two broad dark blue­grey stripes (extensions of caudal peduncle stripes) on upper and lower parts of fin, these more­or­less converging on distal part of middle rays; pectoral fins pinkish hyaline; pelvic­fin rays pale blue, with fin membranes pinkish hyaline.

Preserved coloration. Pattern similar to live coloration: head and body become brown to dark brown, with interorbital area, snout and front of lips dark grey­brown; dark grey to black bar on midposterior part of orbital rim remains; bright orange markings below and behind eye become pale brown to white; indistinct dark grey­brown broad stripe extending from upper part of operculum to upper part of caudal base (best developed posteriorly and more obvious in small specimens); small specimens with second indistinct dark greybrown broad stripe extending from anal­fin base to lower part of caudal­fin base; dorsal and anal fins become dusky hyaline to dark grey­brown, darkest in large specimens; caudal fin becomes pale brown, brownish hyaline posteriorly; dark stripes on caudal fin become dark grey to black; pectoral fins brownish hyaline; pelvic fins brownish hyaline to brown.

Habitat and distribution. Pseudochromis lugubris is known only from southeastern Papua New Guinea ( Fig. 2 ). It has been observed and collected from reef caves, reef overhangs and reef slopes in 6– 15 m. According to Michael (2004: 122), it is “not uncommon on sheltered fringing reefs and on reef faces in Milne Bay.”

Comparisons. Pseudochromis lugubris appears to be closely related to P. bitaeniatus from throughout the West Pacific, and P. tonozukai from off northern Sumatra. They resemble each other, and differ from other pseudochromids, in having a combination of two heavily pigmented stripes on the body (indistinct in P. lugubris and large P. bitaeniatus ), which converge on the midposterior part of the caudal fin, and a rhomboid to trifurcate caudal fin (though this is weakly developed in P. lugubris ). They are readily distinguished by several meristic characters ( Table 1 ): dorsal­fin rays (25–27, usually 26 in P. bitaeniatus , 26–27 in P. lugubris , and 25 in P. tonozukai ); scales in lateral series (42–47 in P. bitaeniatus , 48–50 in P. lugubris , and 34–36 in P. tonozukai ); anterior lateral­line scales (27–35 in P. bitaeniatus , 30–38 in P. lugubris , and 25–27 in P. tonozukai ); and circumpeduncular scales (18–20 in P. bitaeniatus , 20 in P. lugubris , and 16 in P. t o n o z u k a i). Pseudochromis tonozukai has longer pelvic fins than the other two species (second segmented pelvic­fin ray 29.3–30.7 % SL versus 18.4–24.4 % SL in P. bitaeniatus and 19.8– 24.4 % SL in P. lugubris ), though we anticipate considerable ontogenetic variation in this character. The three species also differ markedly in coloration details (compare Figs 1 , 3 and 4–5 ), though, as noted above, P. lugubris has similar preserved and live coloration patterns to large specimens of P. bitaeniatus (see further comments below on possible ontogenetic variation in P. lugubris ). Specimens of P. lugubris key to P. bitaeniatus using the key to Pseudochromis species provided by Gill (2004).

Species Segmented *Scales in lateral series

dorsal rays

Species *Anterior lateral­line scales Circumpeduncular

scales Remarks. The specific epithet is from the Latin, meaning “mournful,” alluding to the relatively sombre coloration and the tear­like marking beneath the eye.

The observation that the broad dark stripes are more prominent in small specimens of P. lugubris suggests that they may be even more conspicuous in small juveniles. This is further suggested by ontogenetic variation in the related P. bitaeniatus ( Gill 2004) .

Michael (2004) included a photograph of this species from Milne Bay, Papua New Guinea. He suggested that it might be conspecific with a species he termed the “Togean dottyback,” photographed by R.H. Kuiter at Tomini Bay, Togean Islands, Indonesia. Although specimens are lacking from this locality to verify their identification, Kuiter’s photographs (one of which was preproduced by Michael, 2004: 121; an additional photograph was sent to the first author by R.H. Kuiter) are almost certainly of large individuals of P. bitaeniatus .

Figures

FIGURE 1. Pseudochromis lugubris, underwater photo, Milne Bay, Papua New Guinea. (Photo by S. W. Michael)

FIGURE 2. Distributional records for Pseudochromis bitaeniatus (closed circles; after Gill 2004: fig. 32), P. lugubris (triangles) and P. t o n o z u k a i (square).

FIGURE 3. Pseudochromis bitaeniatus, underwater photo, Mabul, Sabah, Malaysia. (Photo by R. H. Kuiter).

FIGURE 4. Pseudochromis tonozukai, female, underwater photo, Weh Island, off northern Sumatra, Indonesia. (Photo by T. Tonozuka).

FIGURE 5. Pseudochromis tonozukai, male, underwater photo, Weh Island, off northern Sumatra, Indonesia. (Photo by T. Tonozuka)

Tables

TABLE 1. Frequency distributions for selected meristic characters of Pseudochromis bitaeniatus (after Gill 2004), P. lugubris and P. t o n o z u k a i. * indicates characters for which bilateral counts are included.

	25	26	27	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50
bitaenitatus	4	30	5	­	­	­	­	­	­	­	­	7	15	20	21	10	4	­	­	­
lugubris	­	3	4	­	­	­	­	­	­	­	­	­	­	­	­	­	­	1	4	9
tonozukai	2	­	­	2	1	1	­	­	­	­	­	­	­	­	­	­	­	­	­	­