Manonichthys scintilla, Gill, Anthony C. & Williams, Jeffrey T., 2011

Gill, Anthony C. & Williams, Jeffrey T., 2011, Description of two new species of Pseudochrominae from northern Palawan and Mindoro, Philippine Islands (Teleostei: Perciformes: Pseudochromidae), Zootaxa 3140, pp. 49-59 : 54-58

Manonichthys scintilla new species

Sparkfin Dottyback

Figures 5–6 , Table 2

Holotype. PNM 15176 (from USNM 382743), 27.4 mm SL, Philippines, Mindoro Province, Apo Reef, southern tip on outer reef, coral, rubble field, some sand and soft corals, 5–33 m, J.T. Williams, M. Westneat, K. Carpenter, R. Mooi et al., 3 Mar 2003 (field number BUS 03-05).

Paratypes. ASU 19100, 28.8 mm SL (subsequently cleared and stained), Philippines, Palawan Province, Coron Island, 11°48’58”N 120°15’11”E, outer reef drop off with rock and coral wall to sand and rubble at base, 15–31 m, J.T. Williams, M. Westneat, K. Carpenter, R. Mooi, et al., 7 March 2003 (field number BUS 03-18); FMNH 120315, 2: 23.6–24.6 mm SL, collected with ASU 19100; USNM 382744, 31.5 mm SL, Philippines, Mindoro Province, Apo Reef at north-east tip, 12°41’32”N 120°31’19”E, back reef inside lagoon on live and dead coral with some sand, 2–17 m, J.T. Williams et al., 2 March 2003 (field number BUS 03-01).

Diagnosis. Manonichthys scintilla is distinguished from congeners by the following characters in combination: scales to preopercular angle 3–4; second segmented pelvic-fin ray longest; no dark eye stripe on head; no dark bar on posterior body; pelvic fin with red to orange coloration indistinct and confined to distal part of fin; and caudal fin rounded with posterior margin truncate.

Description (based on five specimens, 23.6–31.5 mm SL). Dorsal-fin rays III,28, last 8 (6–7) segmented rays branched; anal-fin rays III,15, last 12 (7–12) segmented rays branched; pectoral-fin rays 17/17 (17 f5; 18 f3); upper procurrent caudal-fin rays 6; lower procurrent caudal-fin rays 6; total caudal-fin rays 29; scales in lateral series 39/ 38 (35 f1; 36 f1; 37 f3; 38 f3); anterior lateral-line scales 26/27 (22 f3; 23 f1; 24 f3; 27 f1); anterior lateral line terminating beneath segmented dorsal-fin ray 17/18 (13 f1; 14 f1; 15 f3; 16 f2; 18 f1); posterior lateral-line scales 9 + 1/7 + 0 (4–7 +0); scales between lateral lines 4/4; horizontal scale rows above anal-fin origin 12 + 1 + 3/13 + 1 + 3 (12–13 + 1 + 2–3 = 15–17); circumpeduncular scales 16; predorsal scales 19 (17 f1; 18 f1; 19 f2); scales behind eye 2 (2 f1; 3 f3); scales to preopercular angle 4 (3 f1; 4 f3); gill rakers 5 + 12; pseudobranch filaments 8 (7 f1; 8 f3); circumorbital pores 16/16 (17–20); preopercular pores 9/9 (9–10); dentary pores 4/4; posterior interorbital pores 1.

Lower lip incomplete; dorsal and anal fins without well-developed scale sheaths, although sometimes with intermittent scales overlapping fin bases; predorsal scales extending anteriorly to point ranging from anterior AIO pores to posterior nasal pores; opercle with 4–5 relatively well-developed serrations; teeth of outer ceratobranchial- 1 gill rakers well developed mainly on tips only; anterior dorsal-fin pterygiophore formula S/S/S + 3 + 1/1 + 1/1/1 (S/S/S + 3 + 1/1 + 1/1/1 f3; S/S/S + 3 + 1/1/1 + 1/1 f1); dorsal-fin spines moderately stout and pungent; anterior anal-fin pterygiophore formula 3/1/1 + 1/1/1 + 1/1 (3/1/1 + 1/1/1 + 1/1 f2; 3/1/1 + 1/1/1 + 1/1 + 1 f2); anal-fin spines moderately stout to stout and pungent, second spine much stouter than third; pelvic-fin spine moderately stout to stout and pungent; second segmented pelvic-fin ray longest; caudal fin rounded with truncate posterior margin; vertebrae 10 + 16; epineurals 14 (12 f1; 13 f3); epurals 3.

Upper jaw with 3–4 pairs of curved, enlarged caniniform teeth anteriorly, and 4–5 (at symphysis) to 1–2 (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 2–4 pairs of curved, enlarged caniniform teeth anteriorly, and 3–4 (at symphysis) to 1 (on sides of jaw) inner rows of small conical teeth, teeth on middle of jaw larger and curved; vomer with 2–3 rows of small conical teeth, forming chevron; palatine with 1–3 rows of small conical teeth arranged in elongate, suboval patch, anterior part of 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 29.2 (27.6–29.3); orbit diameter 10.6 (10.8–11.1); snout length 6.2 (6.1–6.7); fleshy interorbital width 5.5 (5.7–6.4); bony interorbital width 3.6 (3.8–4.1); body width 13.1 (11.5–13.0); snout tip to posterior tip of retroarticular bone 15.3 (15.3–15.9); predorsal length 34.3 (33.0–35.6); prepelvic length 33.2 (32.6–34.9); posterior tip of retroarticular bone to pelvic-fin origin 19.3 (18.1–21.6); dorsal-fin origin to pelvic-fin origin 29.6 (28.3–30.1); dorsal-fin origin to middle dorsal-fin ray 33.9 (31.7–33.7); dorsal-fin origin to anal-fin origin 43.8 (41.5–42.4); pelvic-fin origin to anal-fin origin 29.9 (28.5–29.5); middle dorsal-fin ray to dorsal-fin termination 28.5 (25.4–28.1); middle dorsal-fin ray to anal-fin origin 27.7 (25.3–27.5); anal-fin origin to dorsal-fin termination 34.7 (33.3–35.2); anal-fin base length 26.6 (26.0–27.1); dorsal-fin termination to anal-fin termination 15.7 (13.4–15.7); dorsal-fin termination to caudal peduncle dorsal edge 10.9 (9.8–11.1); dorsal-fin termination to caudal peduncle ventral edge 19.3 (16.2–17.8); anal-fin termination to caudal peduncle dorsal edge 20.4 (18.1– 19.9); anal-fin termination to caudal peduncle ventral edge 12.0 (11.4–13.6); first dorsal-fin spine 2.9 (2.8–3.3); second dorsal-fin spine 7.3 (6.9–7.6); third dorsal-fin spine 9.5 (9.3–9.8); first segmented dorsal-fin ray 13.1 (11.4– 14.6); fourth last segmented dorsal-fin ray 16.8 (15.6–17.4); first anal-fin spine 4.0 (3.3–4.4); second anal-fin spine 9.9 (8.9–10.8); third anal-fin spine 9.9 (8.9–10.5); first segmented anal-fin ray 13.1 (12.5–13.4); fourth last segmented anal-fin ray 16.4 (14.4–15.6); third pectoral-fin ray 16.8 (15.7–16.7); pelvic-fin spine 12.8 (12.4–12.7); second segmented pelvic-fin ray 24.1 (21.5–23.3); caudal-fin length 25.2 (24.1–25.0).

Live coloration (based on photographs of paratypes from Coron Island (Palawan Province) and Apo Reef (Mindoro Province); Figure 5 ): head greyish blue, darker dorsally, becoming maroon to purplish blue on operculum; iris bluish or reddish grey to bright red, with bright blue suboval ring around pupil; breast and dorsal half of body dark bluish to purplish grey; scales of dorsal part of body each with bright yellow central spot, spots becoming larger ventrally so that grey coloration is reduced to series of stripes along dorsal and ventral edges of horizontal scale rows, and ventral part of body is bright yellow; caudal peduncle bright yellow, with grey edging on some scales; basal third to half of dorsal fin blue-black with one to three horizontal to oblique rows of white to pale blue or pale orange horizontally elongate spots; distal half to two-thirds of fin greyish hyaline, with grey distal margin; anal fin bright yellow, abruptly hyaline on distal third to two-thirds of fin; caudal fin bright yellow basally, with distal margin abruptly hyaline; pectoral fins yellowish hyaline; pelvic fins bright yellow, with fin membranes indistinctly reddish to orange on distal part of fin, and anterior and distal margins grey.

Preserved coloration: pattern similar to live coloration, the blue and grey areas on head and body becoming brown to dark grey-brown; bright yellow areas on head and body become pale yellow to pale brown; blue and dark markings on fins become grey-brown to black; white, yellow, orange and red markings on fins become pale yellow to pale brown.

Habitat and distribution. Manonichthys scintilla is known only from Apo Reef (Mindoro Province) and Coron Island (Palawan Province) ( Fig. 6 ). It has been collected from outer reefs and lagoons in 2 to 33 m. Species of Manonichthys facultatively enter large sponges. However, no large sponges were observed at the collection sites.

Comparisons. Species of Manonichthys are distinguished from other pseudochromine genera in having in combination an incomplete lower lip and an anterior dorsal-fin pterygiophore formula of S*/S/S + 3 + 1*/1 + 1* (usually with four pterygiophores inserting anterior to neural spine 4). Gill (2004) included five species in the genus: M. alleni Gill (2004) from Sabah, Borneo; M. paranox ( Lubbock & Goldman, 1976) from the Great Barrier Reef, Solomon Islands and Papua New Guinea; M. polynemus ( Fowler, 1931) from Sulawesi and Belau; M. splendens ( Fowler, 1931) from eastern Indonesia; and M. winterbottomi Gill (2004) from Cebu, Philippines. Since Gill’s publication, specimens tentatively identified as M. alleni have been collected from Bali and Komodo, Indonesia, and an additional species, M. jamali Allen & Erdmann (2007) , has been described from southwestern Irian Jaya. The seven species are thus distributed allopatrically throughout the Indo-Australian Archipelago ( Figure 6 ). Recent discoveries also necessitate the discussion of some characters used by Gill (2004) to differentiate species in the genus. In the first couplet of his key to species in the genus, among other characters, Gill used black pectoral-fin coloration to distinguish M. paranox and M. winterbottomi from the remaining species; in comparing the two species to other Manonichthys species, he further noted that they were distinctive in having darker body coloration. However, photographs received by the first author from H. Tanaka and R.H. Kuiter indicate that large specimens of M. alleni may become dark grey with entirely or partially black pectoral fins. Moreover, it appears that juvenile specimens of M. winterbottomi may have a live coloration more similar to other species (including M. scintilla ). According to the late H.R. Lubbock’s unpublished field notes, Manonichthys winterbottomi (as “ Pseudochromis cf. paranox ”) were seen swimming near smaller individuals of “ P. s p l e n d e n s,” with which they were “most likely conspecific.” In the same station that yielded the paratypes of M. winterbottomi (field number RL 14-6a, Moalboal, Cebu), Lubbock collected one specimen of “ P. splendens ,” which, according to his notes, was subsequently photographed then lost. In 1987, H. Debelius gave the first author a colour transparency taken by Lubbock, which is probably of the lost specimen. Unfortunately, the slide had been remounted, and Lubbock’s annotations on the original slide mount had not been recorded. However, it does not match any other specimen mentioned in Lubbock notes. It closely resembles M. scintilla , and is reproduced here in Figure 7 for comparison.

Characters useful in distinguishing species of Manonichthys are summarised in Table 2 . Manonichthys scintilla is most similar to M. alleni and M. winterbottomi (assuming our identification of the specimen in Fig. 7 is correct). It differs from M. alleni in the coloration of the pelvic fins; in M. alleni red coloration is present as one or two prominent crimson spots near the base of the fin (see Gill, 2004: pls 2D and 2E), whereas in M. scintilla red coloration is diffuse and confined to the distal part of the fin. Similarly, red coloration in the presumed juvenile of M. winterbottomi is more intense than in M. scintilla , although it is also positioned on the distal part of the fin. Manonichthys scintilla further differs from M. winterbottomi in having the second (rather than the third) segmented pelvic ray longest, the caudal fin rounded with a truncate posterior margin (versus rounded), and fewer scales to preopercular angle (3–4 versus 5–7).

Remarks. The type specimens of M. scintilla (largest specimen 31.5 mm SL) are small compared with the largest known specimens of congeners (largest specimens 50.6–80.0 mm SL), and are probably juveniles. It is likely that the species will show similar ontogenetic variation in body coloration to that shown by other species (except for M. paranox , which is uniformly black as both juveniles and adults). Generally in juvenile Manonichthys the dorsal part of the body is grey and each scale has a bright yellow central spot, which become larger ventrally so that the grey coloration is reduced to a series of stripes along the dorsal and ventral edges of each horizontal scale row, and the ventral part of body is bright yellow. In larger specimens, the grey stripes become wider and extend farther ventrally, so that the entire ventral part of body of larger specimens is grey with small yellow spots on the centre of each scale. If so, it is possible that large specimens may approach the dark coloration shown by adult M. winterbottomi . We note, however, that the largest known specimen of M. scintilla is of similar size to the smallest paratype of M. winterbottomi (30.1 mm SL), which has a dark body and pectoral fins.

Etymology. The specific epithet is from the Latin meaning spark, glimmer or trace, and alludes to the small amount of red coloration in the pelvic fins (when compared with other Manonichthys species with red pelvic-fin markings). It is treated as a noun in apposition.

We thank Mudjekeewis Santos, National Fisheries Research and Development Institute (NFRDI), Philippines, for his efforts to facilitate the collaborative projects in the Philippines that led to the discovery of these new species. Mark Westneat, Kent Carpenter, Randy Mooi, Mark McGrouther, Jerry Finan, Kerryn Parkinson, Jeff Janovetz, Arvin Dantis, Mudjekeewis Santos, Leony Mijares, Luz Romena, November Romena, Lea Acera, Jennifer Fessler, Aaron Rice, Jim Cooper, Geddy Choy, Keith Labuos and Carlitos Ortoll worked with the second author to conduct fieldwork in the Philippines. We thank Sandra Raredon, A. Hay and J. King for variously providing radiographs. The Fish Division staff at the USNM assisted with shipping, receiving and processing specimens at the USNM.

Funding for the second author’s work in the Philippines was provided by the National Museum of Natural History Research Opportunities Fund and the Division of Fishes Leonard P. Schultz Fund.

Figures

FIGURE 5. Manonichthys scintilla, USNM 382744, paratype, 31.5 mm SL, Apo Reef, Mindoro Province, Philippines. (Photo by J. T. Williams)

FIGURE 6. Distribution records for species of Manonichthys: M. alleni (black squares), M. jamali (green square), M. paranox (black dots), M. polynemus (red squares), M. scintilla (white squares), M. splendens (black triangles) and M. winterbottomi (red triangle) (based in part on Gill, 2004: fig. 14).

FIGURE 7. Photo of probable juvenile Manonichthys winterbottomi, Moalboal, Cebu, Philippines. (Photo by H. R. Lubbock).

Tables

TABLE 2. Summary of characters distinguishing Manonichthys species.

Species	Pectoral-fin coloration	Dark eye stripe	Red/yellow coloration on pelvic fins	Dark bar on posterior body
M. alleni	hyaline, dark in some adults	absent	1 or 2, large irregular crimson spots near anterior base of fins	absent
M. jamali	hyaline	absent	absent	present
M. paranox	black	absent	red patch sometimes present on anterior base	absent
M. polynemus	hyaline	absent	large red or yellow patch basally behind 2nd ray	absent
M. scintilla	hyaline	absent	indistinctly reddish to orange distally	absent
M. splendens	hyaline	present	absent	absent
M. winterbottomi	black, possibly hya- line in juveniles	absent	presumed juvenile with pronounced red distally	absent
Species	Caudal-fin shape	Longest pelvic-fin ray	Circumpeduncular scales	Scales to preopercular angle
M. alleni	rounded to truncate or emarginate	second or third	16	4–5
M. jamali	emarginate	second	16–18 (us. 16)	5–6
M. paranox	rounded	second or third	18–21	4–7
M. polynemus	emarginate in juve- niles, lunate in adults	second	16–17 (us. 16)	5–7
M. scintilla	rounded, truncate pos- teriorly	second	16	3–4
M. splendens	rounded, sometimes truncate posteriorly	second (juveniles) or third (adults)	16–17 (us. 16)	5–7
M. winterbottomi	rounded	third	16	5–7
Acknowledgements