Chalinochromis cyanophleps, Kullander & Karlsson & Karlsson & Norén, 2014

Kullander, Sven O., Karlsson, Mikael, Karlsson, Magnus & Norén, Michael, 2014, Chalinochromis cyanophleps, a new species of cichlid fish (Teleostei: Cichlidae) from Lake Tanganyika, Zootaxa 3790 (3), pp. 425-438 : 426-432

Chalinochromis cyanophleps , new species

( Figs. 1–5 ; Table 1 )

Type material. Holotype. NRM 11993, adult female, 113.7 mm SL. Tanzania, Rukwa Region, Nkansi District, Lake Tanganyika, western shore of Namansi village , depth 5–10 m, 7°37'15"S, 30°39'24"E. 22 May 2008. M. Karlsson & M. Karlsson . Paratypes: All with same data as holotype . NRM 59606, adult female 111.2 mm SL ; NRM 59607, 5 adult males, 103.3–129.3 mm SL, 2 adult females, 108.7–111.5 mm SL .

Diagnosis. Distinguished from Chalinochromis brichardi by flank colour brown to dark grey vs. beige or light grey ( Fig. 1 ); dark brown (conspicuous blue in life) stripe below eye, vs. contrasting black vertical stripes on head ( Fig. 1 ); iris and eye ring partly orange, vs. orange colour not or only faintly visible; opercular blotch absent vs. prominent ( Fig. 1 ); black blotch posteriorly in dorsal fin absent vs. present ( Fig. 1 ); dorsal and caudal fins dark with white dots vs. pale and dots absent ( Fig. 1 ); black spot at pectoral–fin base absent vs. present ( Fig. 1 ); more teeth in upper jaw (13–16 vs. 5–10 in hemiseries), and lower jaw (17–26 vs. 2–3 in hemiseries); and slender caudal peduncle (depth 9.9–10.7% SL vs. 11.6–12.4 %). Distinguished from all other species of Chalinochromis by absence of stripes and blotches on head (vs. present); lips not folded over adjacent jaw and not callous or papillate on lip surface outside that close to teeth (vs. lips wide and folded over adjacent premaxilla and dentary, and more or less extensively papillose on aborad surfaces) ( Fig. 2 ); presence of tricuspid inner teeth (vs. exclusively unicuspid); five mandibular lateralis foramina (vs. four). Distinguished from all species of Altolamprologus , Lamprologus , Lepidiolamprologus , Neolamprologus, Paleolamprologus , and Variabilichromis by number of dorsal-fin spines (22–23 vs. 14–20, occasionally 21); from all species of Congo River Lamprologus by first pelvic-fin ray longest (vs. second to third rays longest), and lateral line scales 37–39 vs. 29–37; from all species of Telmatochromis by dentition (inner teeth mostly unicuspid vs. only or predominantly tricuspid), posterodorsal corner of opercle rounded (vs. pointed), and upper jaw projecting (vs. jaws equal); from all species of Julidochromis by absence of bars and bands on body, and scales in longitudinal row 37–39 vs. 36 or less.

Description. Based on all specimens in type series. For general aspect, refer to Fig. 1 . Measurements are summarised in Table 1 . Elongate, moderately compressed laterally. Trunk anteriorly elliptic in cross section, posteriorly more compressed; sides vertical, dorsum and venter rounded. Head relatively short; frontal contour steep, ascending straight or slightly curved, strongly curved above orbit, joining about straight dorsal-fin base contour. In both sexes a low soft swelling anterior to dorsal-fin origin. Interorbital space wide, convex; head contour well removed from orbit. Orbit lateral, in middle of head length, in dorsal half of head, well separated from mouth by deep lachrymal bone. Eye exposed in dorsal view of head, not exposed in ventral view of head. Ventral profile almost straight, horizontal; anal-fin base slightly ascending. Caudal peduncle contours slightly constricted at middle. Snout short, blunt. Mouth low, at ventral contour, relatively small, narrower than interorbital space; upper jaw protruding slightly before short lower jaw. Ascending processes of premaxilla not reaching orbit. Maxilla not reaching to vertical from anterior margin of orbit. Lower jaw articulation anterior to vertical from anterior margin of orbit. Nostril situated at one-third distance from orbital margin to tip of upper jaw. Lips ( Fig. 2A ) relatively narrow, thick; fold of lower lip broadly interrupted anteriorly. Lips smooth except close to teeth where surface beset with short papillae similar to tissue in toothed field of jaws.

Dorsal-fin rays XXII.7 (1), XXII.8 (7), XXIII.7 (1). First dorsal-fin spine 1/3 length of last, inserted above opercle; spines subequal from sixth, gradually slightly longer to last spine; soft dorsal-fin rays all branched or first ray unbranched, gradually slightly longer to fifth or sixth, beyond which shorter; soft portion ending in acute tip at ¼ to beyond middle of caudal fin. Anal-fin rays VI.6 (4), VII.7 (5). First anal-fin spine inserted opposite antepenultimate dorsal-fin spine; spines gradually increasing in length to last; soft anal-fin rays all branched, increasing in length to third or fourth ray, posterior rays shorter; soft portion ending in pointed or blunt tip at caudal-fin base or, usually at ¼ to beyond middle of caudal fin. Pectoral-fin rays 12 (8), 13 (1). Pectoral fin short, not quite reaching to vertical from genital papilla; rounded, fifth ray longest. Pelvic fin long, reaching base of third or fourth anal-fin spine; pointed, outer branch or equally long branches of first ray longest, inner rays gradually shorter. Caudal-fin hind margin rounded or with short straight vertical apex or slightly indented medially. Caudalfin rays viii.i.7+7.i.vii (5), viii.i.7+7.i.viii (2), ix.i.7+7.i.viii (1), ix.i.7+7.i.ix (1)

Scales in longitudinal row 37 (2), 38 (5), 39 (2). Trunk scales moderately large, ctenoid, with free margin. Cheek naked. Predorsal scales minute, cycloid, embedded in thick skin; squamation extending anteriorly to slightly posterior to orbits. Field of minute embedded, cycloid scales extended posteriorly on side between anterior part of dorsal fin and lateral line. Lateral chest scales minute, cycloid, embedded, squamation extended along abdominal side. Midline abdominal scales small, about half size of flank scales, with free margin, cycloid or weakly ctenoid; smaller cycloid scales around anus and genital papilla, and flanking beginning of anal fin. Anterior half of prepelvic area naked, posteriorly minute embedded cycloid scales. Upper lateral line distance from dorsal-fin base anteriorly at about 12–15, posteriorly at 1–1½ scales; reaching posteriorly to below last rays of dorsal fin, not continued to caudal peduncle. Lateral line scales (upper/lower+pored scales) 29/9+17p, 29/10+15p, 29/10+17p, 29/ 11+17p, 30/11+18p, 31/13+13p, 32/10+8p, 32/12+17p, 33/10+15p, each count unique. Lower lateral line reaching forward to above spinous anal fin, anterior to that continued by scattered pored scales or short rows of pored scales reaching almost to cleithrum. Two rows of scales separating upper and lower lateral lines where overlapping above anal fin. Circumpeduncular scales 16 (9), of which 7 above and 7 below lateral lines.

Thick skin along dorsal-fin base, from anterior 1/3 or middle of fin base containing minute cycloid scales; minute cycloid scales in 1–2 rows basally on posterior interradial membranes of spinous portion and all of soft portion, at most extending along half of fin ray. Anal fin with similar basal squamation. Caudal fin covered by dense layer of minute ctenoid scales, leaving naked only posterior part of three middle interradial membranes, and posterior margin of fin. Scales absent from pelvic and pectoral fins.

Gill rakers sparse, short, slender, villiform, 0+1+3 (1), 1+1+3 (3), 2+1+2 (2), 2+3+1 (1), 2+1+4 (1), 3+1+3 (1). Microbranchiospines present externally on second through fourth gill arches. Lower pharyngeal tooth-plate ( Fig. 3 ) broad, wider than long; toothed surface cardiform. Pharyngeal teeth erect, slender, compressed, dense, only little difference in length between largest (posteromedian) and smallest (ultralateral); most teeth bevelled with distinct sharp caudad directed posterior cusp; posteriorly narrow band of hooked teeth with low anterior shelf and longer antrorse posterior cusp. Coronalis pore (NLF0) single. Five lachrymal lateralis openings; infraorbitals 2–5 absent, substituted by series of free neuromasts, infraorbital 6 (dermosphenotic) absent. Five supraorbital pores including nasal pores; 4 pterotic pores, one shared with lower of 4 extrascapular pores. Five mandibular, 2 anguloarticular, and 6 preopercular pores.

Lateral teeth in upper jaw relatively large, slightly recurved canines; anteriorly on each side a slightly enlarged stout canine tooth followed by two slightly smaller canine teeth. Inner teeth in both jaws in about two series, restricted to anterior part of jaw, very short, only tips emerging, mostly recurved, caniniform or with flattened tips much narrower than base; inner teeth close to symphysis somewhat larger and frequently tricuspid, with short lateral cusps emerging from base of median narrow tip. Lateral teeth in lower jaw very short, contrasting in size with anterior teeth comprising a large recurved caniniform tooth followed symphysially by a similar but slightly shorter tooth. Outer teeth in lower jaw procumbent, paralleling ventral head contour, but tips strongly recurved. Series of enlarged caniniform teeth in upper jaw form a curve, whereas those in lower jaw form a transverse, straight palisade. Major enlarged caniniform tooth on each side in both jaws has cusp directed slightly laterad.

Teeth (canines+smaller) in outer row hemiseries in upper jaw, 3+10 (1), 3+12 (4), 3+13 (4); in lower jaw 2+15 (1), 2+18 (1), 2+20 (1), 2+21 (2), 2+24 (1), 3+19 (1), 3+20 (1).

Vertebrae 17+18=35 (3), 18+17=35 (2), 18+18=36 (4). Single supraneural. Vertebrae contained within caudal peduncle 7 (1), 8 (8). Hypurals 2+3, and 4+5 co-ossified.

Colour pattern in preservative ( Fig. 1A ). Pale brownish on cheek, gill cover, underside of head, chest, anteriorly on abdomen; on dorsum anteriorly above lateral line fading to grey posteriorly. Front and top of head grey. Faint dark brown stripe along neuromast row below orbit. Flanks brownish or greyish brown, each scale with light margin. Dorsal fin dark grey, light dots absent or present on interradial membranes of spinous portion; lappets white with black margin; soft portion paler grey, with white margin edged with black, posterior rays with a few white dots. Caudal fin grey, lighter posteriorly; posterior ¼ to ½ with many scattered white dots; posterodorsal margin, in some specimens also posteroventral margin, white with black edge. Anal fin grey, paler distally on soft portion; small white dots present or absent on interradial membranes. Pelvic fin grey with narrow white leading margin. Pectoral fin colourless. Indistinct dark pigmentation at pectoral-fin base. No sexual dimorphism in colour pattern.

Live colouration ( Figs. 4–5 ). Fins bluish; dorsal fin with bright blue margin, continued on dorsal margin of caudal fin. Below eye a blue iridescent stripe. Iris and eye ring partly orange or yellow. A bluish shine forms a faint neon blue stripe along middle of side from slightly posterior to gill opening to above anal-fin origin. Epithel containing inner tooth band in both jaws yellow. The sexes share same live colouration. No variation in colour pattern has been observed in C. cyanophleps . At a few localities (Mvuna Island, Kisi Island, and Kalala Island) juveniles were observed together with adults. Their colour pattern was similar to the adult, but in addition a few dark brown vertical bars were visible.

Comparative morphometrics. Comparative morphometry was conducted on eight specimens of C. cyanophleps ( Table 1 ) and 14 specimens of C. brichardi ( Table 2 ). One specimen of C. cyanophleps (NRM 59606) was excluded from morphometric analysis as it shows signs of stunting. The standard length span is nonoverlapping. All C. cyanophleps are longer (103.3–129.3 mm SL) than the C. brichardi (62.3–94.2 mm SL), and biplot analyses do not exclude the possibility that proportional differences between the two samples may reflect the different length spans. In proportions, the stouter appearance of C. brichardi and more slender appearance of C. cyanophleps is reflected in caudal peduncle proportions ( Tables 1–2 : depth 11.6–12.4 % SL in C. brichardi vs. 9.9–10.7% in C. cyanophleps ; length 15.3–17.4 % SL in C. brichardi vs. 16.9–20.3 % in C. cyanophleps ). The Principal Component Analysis ( Fig. 6 , Table 3 ) separates the two species by body depth, preorbital depth, lower jaw length, pectoral-fin length, and caudal peduncle length. These are also measurements that show considerable individual variation, especially within C. cyanophleps . Field observations suggest that C. cyanophleps can reach total lengths of about 18 cm, whereas C. brichardi only reaches about 14 cm total length.

DNA Barcode. A 685 base-pair fragment of the mitochondrial Cytochrome c subunit 1 (COI) gene was obtained from NRM 59606, and is deposited in GenBank with accession number KJ418181 . The fragment starts at position 37 and ends at position 721 of the COI gene, and includes the standard barcoding region of COI. The most similar published sequence (30 October 2013) is Chalinochromis popelini (GenBank accession number AY263867 ), which is 1.8% dissimilar (p-distance) to C. cyanophleps , corresponding to 12 nucleotide positions (numbered from start of gene): 135C ̓ T; 249G ̓ A; 276A ̓ G; 330C ̓ T; 351G ̓ A; 360A ̓ G; 366C ̓ A; 369C ̓ T; 516A ̓ G; 540G ̓ A; 621G ̓ A; 696G ̓ A.

Etymology. The specific name, cyanophleps , is a Greek adjective meaning blue-veined, and is formed from the Greek ΚΎαΝΟς (blue) and φλεψ (vein, blood vessel), with reference to the conspicuous blue stripe below the eye.

Geographical distribution and habitats. Known only from a small section of the Tanzanian coast of Lake Tanganyika ( Fig. 7 ). Preserved specimens are from Namansi ( Fig. 8 ). A diving survey in 2008 found C. cyanophleps along the Tanzanian coast from Mvuna Island south to Kalala Island, a stretch of about 90 km. It was observed at all the southern islands in the Kipili area (Mvuna, Lupita, Ulwile), and all islands and reefs along the coast into Kala Bay and around Kalala Island (Kisi Island, Lupote Rocks, Kashia Island, Yamsamba Island, Lwilwi Island, Kauchi Island, Semwe Rocks, Popo Rocks, and Fulwe Rocks), with the exception of Lyapinda Rocks where the habitat appeared suboptimal.

Chalinochromis cyanophleps is a cryptic, timorous fish occupying rocky areas with large rocks or boulders. It was observed in the darker parts of the biotope, in dark crevices and caves ( Fig. 5 ), and was often seen swimming belly up against the roof of the cave. It was very rarely seen in open areas. It was encountered at depths between 6 and 45 m. Usually only single individuals or pairs were observed. The species was often seen together with Julidochromis regani and Paracyprichromis nigripinnis , occasionally also with Chalinochromis “bifrenatus”.

Chalinochromis “bifrenatus” is known to occur in the south-eastern part of Lake Tanganyika, and is sympatric with C. cyanophleps between Mvuna Island and Kala Bay at Lusekese, which latter is the southernmost locality for C. “bifrenatus” in Tanzania.

Figures

FIGURE 1. A Chalinochromis cyanophleps, holotype, NRM 11993, adult female, 113.7 mm SL. Lake Tanganyika: Namansi; B C. brichardi, NRM 59629, adult male, 94.2 mm SL. Lake Tanganyika: Cape Kabogo.

FIGURE 2. Anteroventral aspect of snout tip to show differences in lip development. Scale bars 1 mm. A Chalinochromis cyanophleps, NRM 59607, 111.1 mm SL, right side, reversed. B C. brichardi, NRM 59629, 94.2 mm SL, right side, reversed. Insert shows yellow lining of lower jaw in living C. cyanophleps; individual not preserved.

FIGURE 3. Chalinochromis cyanophleps, NRM 59606, 111.2 mm SL, lower pharyngeal jaw. A Occlusal aspect; B close-up of teeth in occlusolateral aspect.

FIGURE 4. Chalinochromis cyanophleps in natural habitat at Namansi, type locality, depth 8 m.

FIGURE 5. Chalinochromis cyanophleps, breeding pair in their nest at Kisi Island, depth 12 m.

FIGURE 6. Scores of morphometric sheared principal component II versus morphometric sheared principal component III from pooled sample of Chalinochromis cyanophleps (N=8), and C. brichardi (N=14).

FIGURE 7. Outline map of Lake Tanganyika showing distribution and type locality of Chalinochromis cyanophleps and collecting sites of comparative material of C. brichardi, C. “ndobhoi” and C. “bifrenatus”.

FIGURE 8. Type locality of Chalinochromis cyanophleps, western shore of Namansi village.