Lamprologus markerti, Tougas & Stiassny, 2014

Tougas, Stephanie & Stiassny, Melanie L. J., 2014, Lamprologus markerti, a new lamprologine cichlid (Teleostei: Cichlidae) endemic to the lower Congo River in the Democratic Republic of Congo, west-central Africa, Zootaxa 3852 (3), pp. 391-400 : 393-398

publication ID	https://doi.org/ 10.11646/zootaxa.3852.3.8
publication LSID	lsid:zoobank.org:pub:E4CB6515-5C85-4E5A-8925-AC520D2D5EC8
DOI	https://doi.org/10.5281/zenodo.4928767
persistent identifier	https://treatment.plazi.org/id/D0F44E92-7C9C-4DA2-9728-053A6D9BE6EE
taxon LSID	lsid:zoobank.org:act:D0F44E92-7C9C-4DA2-9728-053A6D9BE6EE
treatment provided by	Felipe
scientific name	Lamprologus markerti
status	sp. nov.

Treatment

Lamprologus markerti View in CoL , new species

Figures 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 , Tables 1 View TABLE 1 & 3 View TABLE 3 .

Holotype: AMNH 238601 About AMNH , male, 90.0 mm SL, Democratic Republic of Congo, Bas Congo Province , across from Matadi , Congo River at Lufu River confluence, 5°48' 6.60" S, 13°27' 25.80" E, Coll. R. Schelly et al., 19 July 2005. GoogleMaps

Paratypes: AMNH 238602 About AMNH , 6 specimens, 44.5–78.5 mm SL, same locality as holotype GoogleMaps .— MRAC B4-10 View Materials -P-1, 60.4 mm SL, same locality as holotype GoogleMaps .— MCZ 171125 About MCZ , 54.0 mm SL, same locality as holotype GoogleMaps .— AMNH 238603 About AMNH , 2 specimens, 66.0– 72.5 mm SL, Democratic Republic of Congo, Bas Congo Province , Nziya site, Inga, 05°32' 10.20" S, 13°33' 23.40" E, Coll. M.J. Stiassny et al., 17 July 2007 GoogleMaps .— AMNH 238604 About AMNH , 69.0 mm SL, Democratic Republic of Congo, Bas Congo Province , Nziya , downstream of Inga , below Bundi stream of Congo River confluence, 5°33' 22.20" S, 13°33' 13.20" E, Coll GoogleMaps . R. Schelly et al., 16 July 2005 .— AMNH 233568 About AMNH , 43.0 mm SL, (paratype of L. tigripictilis ), Democratic Republic of Congo, Bas Congo Province , Nziya village, 5°32' 15.00" S, 13°33' 36.60" E, Coll GoogleMaps . R. Schelly et al., 24 September 2002 .— AMNH 238652 About AMNH , 45.0 mm SL, Democratic Republic of Congo, Bas Congo Province , Main channel of Congo River, upstream of Boma, 5°51' 49.80" S, 13° 4' 24.60" E, Coll GoogleMaps . R. Schelly et al., 18 July 2005 .— ZSM 37820, 2 specimens, 58.5–64.5 mm SL, Democratic Republic of Congo, Bas Congo Province , Congo River, weeds upriver of boat landing site, 5°51’ 48” S, 13°4’ 28” E, Coll. D. Neumann, 16 July 2008 GoogleMaps .— ZSM 38391, 102.5 mm SL, Democratic Republic of Congo, Bas Congo Province , Congo River, purchased at Boma fish market, 5°51’ 46.90” S, 13°4’ 3.99” E, Coll. D. Neumann, 16 July 2008 GoogleMaps .

Additional non-type specimens examined: AMNH 238654 About AMNH , 14 specimens , 2 C&S.— AMNH 241592 About AMNH , 16 specimens , 1 C&S.— AMNH 238650 About AMNH , 23 specimens , 6 C&S.

Differential diagnosis. L. markerti is readily distinguished from L. tigripictilis by the presence of 4–6 broad dark bars on the flanks (versus 7–10 narrow bars), and from L. werneri in the possession of 14 (vs. 15) precaudal vertebrae. It differs from both L. tigripictilis and L. werneri in a reduced number of gill rakers on the first arch (9–11 versus 12–17), a longer head (32.1–34.7% SL versus 29.3–31.9 and 29.1–32.9% SL, respectively), and a longer predorsal length (33.0–35.9% SL versus 29.3–32.7 and 28.5–32.6 % SL respectively). Further, L. markerti lacks an intestinal loop present in both L. tigripictilis and L. werneri , and has a highly reduced infraorbital series often consisting only of the first infraorbital (lachrymal) element.

Description. A Lamprologus attaining a maximum-recorded size of 102.5 mm SL (mature male, ZSM 38391), with general body shape and appearance as in Figures 3 View FIGURE 3 and 6A View FIGURE 6 . Counts and proportional measurements for holotype and 16 paratypes as in Table 1 View TABLE 1 with comparable ranges for L. tigripictilis , the taxon with which it has previously been confused, in Table 2. Body relatively shallow (BD 20.2–24.8% SL), greatest depth at level of first dorsal fin-spine. Head long (32.1–34.7% SL), snout prominent, with well-developed, fleshy lips. Dorsal head profile rises at angle of 40–50° to mid-orbit, then rises steeply to nape. Large males with a prominent, fat filled nuchal hump ( Fig. 3 View FIGURE 3 ). Dorsal and ventral body profiles slightly convex to relatively deep caudal peduncle.

Dorsal fin XVI–XVIII (mode: XVIII) 7 or 8 (mode: 7). Anal fin IV–VI (mode: VI) 5–7 (mode 6). Spines in both fins gradually increase in length posteriorly. Dorsal and anal fins with tapering filamentous extensions to middle of caudal fin, longer in mature males than females. Caudal fin large, paddle-shaped with 14 branched rays; fin often appearing subacuminate in preserved specimens. Pectoral fin short, not reaching anus. Pelvic fins also short but somewhat produced, reaching just short of anus or to between anal fin and anus. Second branched ray in pelvic fin longest in both sexes.

Jaws isognathus, inner and outer row teeth in both jaws pointed unicuspids. Single series of eight enlarged, recurved, procumbent canines situated anteriorly on premaxilla ( Fig. 4A View FIGURE 4 ), with largest pair displaced dorsolaterally. Behind the procumbent canines a single row of slightly enlarged canines gradually taper in size beginning at midlength of premaxilla. Outer row teeth extend almost entire length of both dentary and premaxilla. Lower pharyngeal jaw wider than long, with straight ventral suture ( Fig. 4F View FIGURE 4 ). Usually 24–28 teeth in posterior row, symphysial teeth moderately robust ( Fig. 4E View FIGURE 4 ), become slender laterally. Gill rakers markedly elongate, nondenticulate and slender ( Fig. 4D View FIGURE 4 ). Nine to eleven rakers along outer row of first gill arch; one hypobranchial, 4–6 ceratobranchial rakers, often one raker in angle of arch, and 3 or 4 epibranchial rakers.

Flank scales large, uniformly sized, and ctenoid. Chest and cheek scaleless. Scales on nape and above upper lateral line, to level of 7–9 th dorsal-fin spine, markedly smaller than those on flanks Opercle and subopercle with few, scattered, deeply embedded cycloid scales. Proximal half of caudal fin covered with small ovoid, ctenoid scales. Pored lateral line scales 34–36. Upper and lower lateral lines usually overlap by 2 or 3 scales. Total number of vertebrae: 32 or 33, comprised of 14 precaudal and 18 or 19 abdominal centra.

Supraoccipital crest relatively low, with no frontal ridge extending to neurocranial lateral-line foramen ( Fig. 4B View FIGURE 4 ). Infraorbital series consisting of broad, plate-like first infraorbital (lachrymal) bearing 5 inflated, sensory-canal pores. Small second infraorbital element polymorphically present and, when present, often lacks tubular sensory canal ( Fig. 4C View FIGURE 4 ). In some individuals a second infraorbital element is entirely lacking ( Fig. 6A View FIGURE 6 ).

Digestive tract short; esophagus leads to small bulbous stomach, from which intestine exits left side at transition zone between esophagus and stomach. Intestine exhibits single, rostro-caudad loop before descending to anus ( Fig. 5A View FIGURE 5 ). Total length of tract (unraveled but not stretched) c. 40–50% SL ( Table 3 View TABLE 3 ).

Coloration in life ( Fig. 3A View FIGURE 3 ): in mature males, base body coloration mauve gray becoming pale silver ventrally. Turquoise reflective streak under eye, on posterior of cheek, and extending over opercle. Flank scales ringed with dark pigment strongly contrasting with silvery central field. Four or 5 dark vertical bars of uniform thickness, originating at base of dorsal fin and extending over flanks but not reaching to ventrum. Dorsal, anal and caudal fins proximally covered with alternating pale and dark spotting. Pectoral fin clear, pelvic fin pale silver along distal margin. Scaleless, dark, opercular spot obscured by turquoise iridescence. In preservation ( Figs. 3B View FIGURE 3 & 6A View FIGURE 6 ), base body coloration creamy brown, slightly darker dorsally becoming pale cream ventrally. Four or 5 dark vertical bars on flanks, and flank scales ringed with brown pigment contrasting with pale cream central field. Dorsal and anal fins brown with alternating pale and dark maculae variously evident, but always present. Caudal fin membranes with conspicuous rows of maculae, strongest proximally. All fin spotting more prominent in mature males than in females and juveniles.

Distribution ( Fig. 1 View FIGURE 1 ). L. markerti occupies a roughly 100-km stretch of the LCR from the region of Nziya Village located below the large Inga Rapids to the start of the short Congo estuary just below Boma. The species appears to be a habitat generalist found over a range of substrates from marginal riffle and rocks near rapids, to stiller water habitats over sand and mud.

Etymology. Named for Jeffrey Markert whose initial analyses of cichlid population structure in the region of the large Inga Rapids stimulated this morphological study.