Haplochromis goldschmidti Witte, Westbroek & de Zeeuw

de Zeeuw, Marnix P., Westbroek, Irene, van Oijen, Martien J. P. & Witte, Frans, 2013, Two new species of zooplanktivorous haplochromine cichlids from Lake Victoria, Tanzania, ZooKeys 256, pp. 1-34 : 13-18

Haplochromis goldschmidti Witte, Westbroek & de Zeeuw sp. n. Figs 6-9, Table 3

Cheironyms used.

Haplochromis "dusky argens"; Goldschmidt 1989a: 148, 158, 160, 162, 166; Goldschmidt and de Visser 1990: 129, 130, 132; Goldschmidt 1991: 182, 187; van der Meer 1991b: 9-11, 15, 16, 19-22; van der Meer et al. 1995: 116, 117, 122-124, 126, 127.

Type-locality.

Tanzania, Lake Victoria, Emin Pasha Gulf (ca 2°35'-2°41'S; 31°47'-31°59'E).

Holotype.

RMNH.PISC.835733, ♂, 60.3 mm SL, 23.vi.1985, HEST.

Paratypes.

Collected by the Haplochromis Ecology Survey Team (HEST). Size of specimens given as standard length. RMNH.PISC.804804, ♂, 53.6 mm, 23.vi.1985; RMNH.PISC.80481, ♂, 56.8 mm, 23.vi.1985; RMNH.PISC.804824, ♂, 63.4 mm, 23.vi.1985; RMNH.PISC.804834, ♂, 52.9 mm, 23.vi.1985; RMNH.PISC.804844, ♂, 65.3 mm, 23.vi.1985; RMNH.PISC.804854, ♂, 69.2 mm, 23.vi.1985; RMNH.PISC.804934, ♂, 50.7 mm, 23.vi.1985; RMNH.PISC.804944, ♂, 52.2 mm, 23.vi.1985; RMNH.PISC.804955, ♂, 58.7 mm, 23.vi.1985; RMNH.PISC.804965, ♂, 57.4 mm, 23.vi.1985; RMNH.PISC.804975, ♂, 55.0 mm, 23.vi.1985; RMNH.PISC.804985, ♂, 60.4 mm, 23.vi.1985; RMNH.PISC.804995, ♂, 67.4 mm, 23.vi.1985; RMNH.PISC.805015, ♂, 61.1 mm, 23.vi.1985; RMNH.PISC.805025, ♂, 62.6 mm, 23.vi.1985; RMNH.PISC.805035, ♂, 57.7 mm, 23.vi.1985; RMNH.PISC.805075, ♂, 52.8 mm, 23.vi.1985; RMNH.PISC.805085, ♂, 62.9 mm, 23.vi.1985; RMNH.PISC.805125, ♂, 59.3 mm, 23.vi.1985; RMNH.PISC.805135, ♂, 63.6 mm, 23.vi.1985; RMNH.PISC.805145, ♂, 61.7 mm, 23.vi.1985; RMNH.PISC.835743, ♂, 62.6 mm, 23.vi.1985; RMNH.PISC.835754, ♂, 57.5 mm, 23.vi.1985; RMNH.PISC.83576, ♂, 58.2 mm, 23.vi.1985; RMNH.PISC.835773, ♂, 62.5 mm, 23.vi.1985; RMNH.PISC.835783, ♂, 69.2 mm, 23.vi.1985; RMNH.PISC.835793, ♂, 64.9 mm, 23.vi.1985; RMNH.PISC.835803, ♂, 62.9 mm, 23.vi.1985; RMNH.PISC.835813, ♂, 51.7 mm, 23.vi.1985; RMNH.PISC.835823, ♂, 52.4 mm, 23.vi.1985; RMNH.PISC.835833, ♂, 57.7 mm, 23.vi.1985; RMNH.PISC.835843, ♂, 55.4 mm, 23.vi.1985; RMNH.PISC.835853, ♂, 61.9 mm, 23.vi.1985; RMNH.PISC.835863, ♂, 65.4 mm, 23.vi.1985; RMNH.PISC.836643, ♂, 56.2 mm, 23.vi.1985; RMNH.PISC.836653, ♂, 63.2 mm, 23.vi.1985; RMNH.PISC.836663, ♂, 65.5 mm, 23.vi.1985; RMNH.PISC.836673, ♂, 60.7 mm, 23.vi.1985; RMNH.PISC.836683, ♂, 64.9 mm, 23.vi.1985; RMNH.PISC.836693, ♂, 65.8 mm, 23.vi.1985; RMNH.PISC.836703, ♂, 60.0 mm, 23.vi.1985; RMNH.PISC.836951, 2, 4, ♂, 56.2 mm, 23.vi.1985; RMNH.PISC.836961, 4, ♂, 58.0 mm, 23.vi.1985; RMNH.PISC.836991, 5, ♂, 61.5 mm, 23.vi.1985; RMNH.PISC.837001, 5, ♂, 55.3 mm, 23.vi.1985; RMNH.PISC.837012, 5, ♂, 61.6 mm, 23.vi.1985; RMNH.PISC.837021, 2, 5, ♂, 61.1 mm, 23.vi.1985; AMNH 2550365, ♂, 61.4 mm, 23.vi.1985; BMNH 2012.1.5.34, ♂, 61.6 mm, 22.vi.1985; NSMT-P 1069604, ♂, 64.8 mm, 22.vi.1985.

1 dissected to describe the oral jaws and contents of stomachs and intestines; 2 dissected to describe pharyngeal jaws and to count gill filaments; 3 proportional measurements taken; 4 colour picture available; 5 colour picture of anal fin available.

Diagnosis.

Small sized (<7 cm SL), slender (BD <28% SL), micrognathic, zooplanktivorous Hapolochromis species (LJL <45% HL in all but one specimens) with a slightly curved to straight dorsal head profile. Mainly bicuspid teeth in oral jaws. Generally premaxillary dentigerous arm edentulous over caudal 1/5 - 1/4. Males silvery with dusky flush on chest, flank, ventral side and ventral half of caudal peduncle.

Description.

Proportional measurements of type material provided in Table 3.

Habitus. See Fig. 6. Body slender. Dorsal head profile straight to slightly curved. Premaxillary pedicel slightly prominent. Mouth oblique. Lips not thickened. Medial part of premaxilla slightly expanded to expanded. Caudal part of maxilla not bullate. Vertical through caudal tip of maxilla running through iris, just rostral to pupil. Lateral snout outline isognathous and obtuse, in large specimens sometimes slightly prognathous. Jaws equal anteriorly or lower jaw slightly protruding. Mental prominence slightly pronounced. Retro-articular processes of right and left mandible touching each other, interrupting ventral body outline. Eye approximately circular (occasionally slightly elongated) and medium to large in size. Distinct aphakic aperture present in pupil. Cephalic lateral line pores not enlarged.

Scales. Cheek, gill cover, and rostral part of the dorsal head surface with cycloid scales. Nape and rostral part of dorsum with a mixture of cycloid and weakly ctenoid scales. Chest mainly with ctenoid scales, occasionally weakly ctenoid or cycloid. Scales on remaining part of body mainly ctenoid. Scales on chest smaller than those on ventral and ventro-lateral part of body; size transition gradual. Small elongated scales on basal quarter to one third of caudal fin. Four to 5.5 (mode 5) scales between upper lateral line and dorsal-fin origin, four to seven (mode 6) between between pectoral- and pelvic-fin bases.

Fins. Pelvic fins just reaching or slightly surpassing rostral-most point of anal-fin origin. Pelvic fins with first soft rays slightly produced, occasionally filamentous. Caudal tip of anal fin not reaching caudal-fin origin. Caudal-fin outline truncate to slightly emarginate.

Gill apparatus. Description of gill apparatus based on lateral gill rakers and lateral hemibranch of first gill arch. Number of gill rakers on lower part of first gill arch 10-12 (one specimen with 13). Lower two to three rakers reduced (= very short), next one to two short, followed by two to seven slender and longer ones. Remaining rakers hooked, bifid, or trifid. Generally rakers closely set, viz. touching each other over major part of length. Number of gill filaments 87 to 93.

Viscera. Ratio between intestine length and SL: 1.0-1.2 (n = 5).

Oral jaws. (Fig. 7 A, B) Premaxillary ascending arm equal to or longer than dentigerous arm (asc./dent. arm ratio 1.0 to 1.1). Angle between arms 77° to 81°. Symphyseal articulation facet not present, lower jaw slightly more elongated than generalized type (length/height ratio 2.3 to 2.8). Upper half of dentary with distinct outwardly directed flare. Mental prominence slightly pronounced.

Oral teeth shape. (Fig. 7 A, B) Teeth of outer row in both jaws mainly bicuspid, with some unicuspid or tricuspid teeth interspersed. Major cusp of bicuspids isoscelene to subequilateral, protracted and acutely pointed. Flange occasionally present on major cusp. Minor cusp short compared to major cusp. Cusp gap rather narrow. In labial view neck moderately slender to normal, crown moderately expanded. In lateral view, crown compressed. Outer-row teeth in both premaxilla and lower jaw recurved. Inner rows in both jaws with mainly tricuspid or weakly tricuspid teeth.

Oral teeth size. Outer-row teeth relatively slender, gradually decreasing in size from rostral to caudal.

Dental arcade and tooth band. Rostrally dental arcade rounded. Outer row occupying 3/4 to 4/5 of premaxillary dentigerous arm. One to two inner rows in both jaws.

Teeth counts and setting. Outer row of upper jaw (l+r premaxilla) with 33-47 teeth. In both jaws outer-row teeth regularly set. Teeth set wider rostrally than laterally.

Tooth implantation. Outer-row teeth of premaxilla rostrally erect. Inner-row teeth recumbent. Outer-row teeth of lower jaw slightly procumbent, inner-row teeth erect.

Lower pharyngeal element. (Fig. 7 C, D) Lower pharyngeal element relatively small and slender (length/width ratio 1.2-1.3). Dentigerous area slightly broader than long (length/width ratio 0.7-0.9). Suture straight.

Pharyngeal teethcounts. Caudal-most transverse row with 25-34 teeth, medial longitudinal rows with nine to 10 teeth.

Pharyngeal teeth shape. Teeth in caudal-most transverse row hooked, major cusp only slightly incurved, blunt to slightly acute. Other teeth bevelled or pronounced. All teeth relatively fine and slender, medial teeth not coarser than other teeth.

Vertebrae. Total number of vertebrae in 19 specimens: 30 (2), 31 (16) or 32 (1), comprising 13-14 abdominal and 16-18 caudal vertebrae.

Live colouration males. (Fig. 8 A, B) Sexually active males with grey-white snout, cheek and gill cover. Lips grey-white, generally with distinct black pigment spots. Eye with grey outer ring and silver inner ring. Dorsal head surface and dorsum silvery-grey. Chest, ventral side, flank and ventral part of caudal peduncle silvery-grey with dusky flush. Flush most distinct on flank and caudal peduncle and occasionally absent on ventral side, sometimes extending over suboperculum, interoperculum, branchiostegal membrane and lower jaw.

Pelvic fins black. Anal fin rostrally hyaline-grey with bluish sheen, remaining part hyaline. One to two pale-yellow to yellow egg dummies surrounded by hyaline ring on caudal part of anal fin. Caudal fin hyaline with bluish sheen; dusky flush on caudal peduncle may extend over rostral part of caudal fin. Dorsal fin hyaline with bluish sheen and faint dusky lappets.

Dark grey to blackish markings: Faint nostril-, interorbital- and supraorbital stripes sometimes present. Lachrymal stripe occasionally slightly longer than in Haplochromis argens , but often less distinct. Preopercular vertical stripe generally not clear. Opercular blotch present.

Preserved colouration of

males.

(Fig. 9) Body light brown. Chest, ventral side, flank and ventral part of caudal peduncle dusky to dark brown. Dark brown colour on caudal peduncle sometimes giving impression of broad mid-lateral band. Fins transparent to light grey-brown except for pelvics, which are black in adult males. Same markings present as in live specimens.

Distribution.

Haplochromis goldschmidti is only known from the southern part of the Emin Pasha Gulf of Lake Victoria (Fig. 1).

Habitat.

Haplochromis goldschmidti was caught over mud bottoms at depths of 4-10 m.

Food.

Stomach and intestines of five examined specimens caught by day contained mainly zooplankton (mainly copepods, but also some cladocerans) and some insects ( Chaoborus larvae and pupae).

Breeding.

Based on the egg dummies on the anal fin of males, Haplochromis goldschmidti is probably a female mouth brooder.

Etymology.

This species is named in honour of Dr Tijs Goldschmidt in appreciation for his work on haplochromine cichlids of Lake Victoria. As a member of the Haplochromis Ecology Survey Team, Tijs Goldschmidt worked in Tanzania (1981-1986) on the ecology and evolution of zooplanktivorous and detritivorous cichlids. Haplochromis goldschmidti is one of the species on which he based his theory on the possible role of egg-dummy divergence in speciation of haplochromines ( Goldschmidt and de Visser 1990). With “Darwin’s Dreampond" ( Goldschmidt 1996) - originally published as "Darwins Hofvijver" (Godschmidt 1994) and translated in eight languages - Tijs Goldschmidt started his career as a writer and brought the human-induced extinction of the Lake Victoria cichlids to the attention of a worldwide public. The specific epithet, goldschmidti,is a Latinized version (genitive case) of the surname.

Comparisons.

Sexually active males of Haplochromis goldschmidti and Haplochromis argens are very similar, but distinguishable by live colouration. Haplochromis goldschmidti has a dusky flush on its flank and Haplochromis argens a yellow to greenish sheen. In contrast to Haplochromis argens , red is generally absent on the fins of Haplochromis goldschmidti , only occasionally very faint traces of red are present on the caudal and dorsal fins. Haplochromis goldschmidti has plain yellow egg spots, while the egg spots of Haplochromis argens are orange yellow ( Goldschmidt and de Visser 1990). Generally, Haplochromis goldschmidti has more pigment spots on its lips than Haplochromis argens .The body depth in Haplochromis goldschmidti is less deep than in Haplochromis argens . The snout width, lachrymal width and lower jaw width are generally larger in Haplochromis goldschmidti (Tables 1, 3, 4).

Sexually active males of Haplochromis goldschmidti are distinguished from Haplochromis tanaos and Haplochromis thereuterion , two other slender zooplanktivores, by colouration. A distinct mid- and dorsal-lateral band is absent in males of Haplochromis goldschmidti , whereas they are present in Haplochromis tanaos and Haplochromis thereuterion (sometimes difficult to distinguish in the latter). A nape band is lacking in Haplochromis goldschmidti , but present in Haplochromis tanaos .