Lamprologus tigripictilis, SCHELLY & STIASSNY, 2004

SCHELLY, ROBERT C. & STIASSNY, MELANIE L. J., 2004, Revision of the Congo River Lamprologus Schilthuis, 1891 (Teleostei: Cichlidae), with Descriptions of Two New Species, American Museum Novitates 3451, pp. 1-40 : 33-37

Lamprologus tigripictilis , new species

Figures 28–31 , Table 8, Plate 2d

HOLOTYPE: AMNH 233609, Congo River mainstream a few kilometers northeast of Kinganga, 5 ° 16 ̍ S, 13 ° 47 ̍ E, 7/12/1973, T.R. Roberts and D.J. Stewart.

PARATYPES: AMNH 233610 (N = 4), collected with holotype ; AMNH 233568 (N = 1), Nziya, near Inga, Congo River mainstream, 05 ° 32 ̍ S, 13 ° 34 ̍ E, 9/24/2002, C. Shumway et al. ; BMNH 1899.2.20.10, Matadi , Lower Congo, 05 ° 49 ̍ S, 13 ° 27 ̍ E ; MRAC 118708–118709 (also paratypes of Lamprologus werneri Poll, 1959 ), Inga , arm of Congo River , 05 ° 29 ̍ S, 13 ° 34 ̍ E, 10/6/ 1957, A. Ruzette ; MRAC 118710 (also paratype of Lamprologus werneri Poll, 1959 ), Inga , arm of Congo River , 05 ° 29 ̍ S, 13 ° 34 ̍ E, 10/7/1957, A. Ruzette ; MCZ 50201 (N = 17), Congo River near Wombe, about 10 km north of Gombe­Matadi and 1 km downstream from mouth of Luasi River , 04 ° 54 ̍ S, 14 ° 42 ̍ E, 7/05/1973, T.R. Roberts and D.J. Stewart ; MCZ 50247 (N = 3), Congo River mainstream near Bulu, west of Luozi , 5 ° 1 ̍ S, 14 ° 1 ̍ E, 7/15/1973, T.R. Roberts and D.J. Stewart ; MCZ 50419 (N = 6), Congo River mainstream near Isangila, 5 ° 18 ̍ S, 13 ° 36 ̍ E, 8/ 15/1973, T.R. Roberts and D.J. Stewart .

ADDITIONAL MATERIAL EXAMINED: 472 specimens. Boma (05 ° 50 ̍ S, 13 ° 03 ̍ E) MRAC 48562, 1/1/1937 – 8/4/1937, Delguste. Tadi, near Kibunzi , Congo River mainstream (5 ° 14 ̍ S, 13 ° 56 ̍ E) MCZ 50308 (N = 71), 7/ 21/1973, T.R. Roberts and D.J. Stewart. Downstream a few kilometers from Kinganga , Congo River mainstream near mouth of Grande­Pukusi River (5 ° 20 ̍ S, 13 ° 43 ̍ E) MCZ 50339 (N = 72), 7/11/1973, T.R. Roberts and D.J. Stewart. Congo River mainstream few kilometers NE of Kinganga (5 ° 16 ̍ S, 13 ° 47 ̍ E) MCZ 50390 (N = 75), 7/ 12/1973, T.R. Roberts and D.J. Stewart. Congo River mainstream, upstream from Inga on south bank (05 ° 27 ̍ S, 13 ° 36 ̍ E) MCZ 50473 (N = 219, 1 c&s), 8/01/1973, T.R. Roberts and D.J. Stewart; USNM 216359 (N = 20, 2 c&s), 8/01/1973, T.R. Roberts and D.J. Stewart. Congo River mainstream, near Inga (05 ° 31 ̍ S, 13 ° 37 ̍ E) MCZ 50550 (N = 14), 8/04/1973, T.R. Roberts and D.J. Stewart.

DIFFERENTIAL DIAGNOSIS: The 9–10 dark bars on the flanks of Lamprologus tigripictilis , n.sp., are unique among the Congo River species of Lamprologus . Lamprologus tigripictilis , n.sp., is further distinguished from L. lethops and L. symoensi by its regularly imbricating, large, uniformly sized flank scales, and from L. mocquardi by its uniformly dark pigment around the exposed margins of flank scales, giving the appearance of chain mail. A shallow supraoccipital crest further distinguishes L. tigripictilis , n.sp., from L. congoensis and L. tumbanus , and pelvic fins extending beyond the anus distinguish L. tigripictilis , n.sp., from L. werneri and L. teugelsi , n.sp. Finally, the possession of 14 precaudal vertebrae in L. tigripictilis , n.sp., instead of 15, further serve to differentiate the species from L. werneri .

DESCRIPTION: Counts and measurements for the holotype, paratypes AMNH 233610 (N = 4), BMNH 1899.2.20.10, and MRAC 118708–118710, and additional specimens are given in table 8. An elongate, relatively shallow­bodied species (BD 17.1–24.4%, mean 21.2% of SL), though adult males have greater relative body depth than males of L. werneri . Greatest body depth at about base of third dorsal fin spine. Head length 29.4– 33.1%, mean 31.4% of SL. Head profile rises at angle of 40–50 °. In adult males head profile steepest, rising at 50 ° and curving abruptly toward horizontal above orbit. Both dorsal and ventral body profile slightly convex, curving most sharply at beginning of caudal peduncle. In many preserved large males, including holotype, loose skin folds in nape region give appearance of nuccal hump, but folds are devoid of muscle or fatty tissue.

Fins: Dorsal fin XVIII–XIX (mode XVIII) 8–10 (mode 9). Anal fin V–VII (mode VI) 6–8 (mode 7). Spines in both fins of gradually increasing length posteriorly. Dorsal and anal fins with tapering filamentous extensions reaching to middle of caudal fin. Caudal fin large, rounded, and paddle­shaped, with 14 branched rays; often appearing lance­shaped, subacuminate in preserved specimens or when adducted. Pectoral fins short, not reaching vertical through anus. Pelvic fins in both sexes somewhat produced, reaching to between anus and anal fin origin, with second ray longest in fin.

Teeth (fig. 29a): Jaws isognathous, but with lower lip sometimes protruding slightly, with both outer and inner row teeth pointed unicuspids in both jaws. Single series of eight enlarged, recurved, procumbent canines situated anteriorly in jaws, with most lateral teeth largest. Posterior to these canines are single rows of slightly enlarged canines extending almost entire length of dentary and premaxilla. Inner teeth are small and caniniform, in about 4 irregular rows, and tapering by mid­jaw to single row.

Gill Rakers (fig. 29b): Slender, elongate, non­denticulate. Twelve to 17 gill rakers along outer row of first gill arch. Two rakers present on hypobranchial, 7–10 rakers along ceratobranchial, almost always single raker in angle of arch, and 4–6 rakers on epibranchial.

Lower Pharyngeal Jaw (fig. 29c): Wider than long, with strongly interdigitating ventral suture. Usually 24–28 teeth in posterior tooth row. Median teeth moderately robust; lateral teeth slender. Teeth beveled or bluntly hooked.

Scales: Flank scales large, ctenoid, and regularly imbricating. Pored lateral line scales 35–37. Upper and lower branches of lateral line sometimes overlap by 1–2 scales. Cheek and chest naked; belly with small scales. Large, embedded scales on opercle and subopercle. Transition to small scales above anterior portion of lateral line, with small scales continuing anteriorly to about midway between dorsal fin origin and eye. Caudal fin with small scales over more than one­half of its length.

Vertebrae: 31–33; 14 + 17 (2), 14 + 18 (33), 14 + 19 (1).

Additional Osteology (fig. 30). Infraorbital series comprised of broad, platelike lachrymal with 5–6 large sensory canal pores and 1, sometimes 2 tubular infraorbitals adjacent to lachrymal. Dermosphenotic absent. Single supraneural present. Supraoccipital crest low, frontal ridge present and extends anteriorly to median coronal pore (NLF0).

Coloration: In life, base body coloration is dark gray­brown. Dorsum quite dark; brownish anterior to dorsal fin origin, more gray posteriorly. Nine to 10 relatively dark vertical bars of varying thickness along flanks. Scaleless, dark opercular spot present. Dorsal and anal fins blackish. Caudal fin membranes covered with rows of black maculae, often blending together to form about six blackish vertical bands. Transition from gray­brown through yellowish to white on belly. Hints of yellow on cheek, bluish highlights around ventral edge of orbit posterior to lachrymal. Individual flank scales with dark pigment distributed uniformly along exposed posterior margin, creating intersecting rows of thin, oblique bands of pigment presenting appearance of chain­link fence or chain mail. Preserved coloration dark brown, with blackish dorsal, anal, caudal, and pelvic fins. Banding and spotting visible on caudal fin.

DIET: Gut short and simple, length 50– 55% of SL. Gut contents included sand, detritus, and insect parts, including apparently aquatic insect larvae and an adult dipteran.

DISTRIBUTION (fig. 31): Lower Congo River mainstream, from just downstream of mouth of Inkisi River to Matadi. Upstream portion of L. tigripictilis , n.sp., range overlaps with the most downstream occurrences of L. werneri .

ETYMOLOGY: The specific name, tigripictilis , from the Latin tigris, for tiger, and pictilis, for colored or painted, refers to the characteristic pattern of dark bands on the flanks of this species.

REMARKS: In the several hundred specimens they identified as Lamprologus werneri from the lower Congo Rapids, Roberts and Stewart (1976) mention in passing the possibility of two color varieties. In notes accompanying that material at MCZ, specimens from rapids in the region of Inga were described as ‘‘barred­variety werneri ’’. This ‘‘barred­variety werneri ’’ is described herein as L. tigripictilis , n.sp. Within Poll’s paratype­series for L. werneri are three specimens herein included as paratypes of L. tigripictilis , n.sp.

As is the case with L. lethops , L. tigripictilis , n.sp., appears to be restricted to the lower Congo rapids in the region of Inga. As a rapids endemic it should be a species of particular concern when considering the potential impacts of the new dam at Inga (see remarks for L. lethops ).

Figures

Plate 2. (a) Lamprologus symoensi, paratype, MRAC 79001.6284–85, female, 46 mm SL; (b) Lamprologus lethops, holotype, MCZ 50248, male, 26 mm SL; (c) Lamprologus teugelsi, n.sp., holotype, AMNH 233611, female, 60 mm SL; (d) Lamprologus tigripictilis, n.sp., holotype, AMNH 233609, male, 62 mm SL.

Fig. 28. Lamprologus tigripictilis, n.sp., holotype, AMNH 233609, male, 62 mm SL, drawn by Ian Hart.

Fig. 29. Lamprologus tigripictilis, n.sp., USNM 216359: (a) premaxilla; (b) first gill arch; (c) lower pharyngeal jaw dorsal view; (d) lower pharyngeal jaw ventral view.

Fig. 30. Lamprologus tigripictilis, n.sp., USNM 216359: (a) neurocranium, first vertebra, and supraneural; (b) lachrymal and adjacent infraorbitals.

Fig. 31. Collection localities of Lamprologus tigripictilis, n.sp.