Astatoreochromis alluaudi Pellegrin, 1904

Banyankimbona, Gaspard, Vreven, Emmanuel & Snoeks, Jos, 2013, A revision of the genus Astatoreochromis (Teleostei, Cichlidae), East-Africa, European Journal of Taxonomy 39, pp. 1-21 : 10-13

Astatoreochromis alluaudi Pellegrin, 1904

Fig. 5

Alluaud’s haplo, local names: ‘Ifuro muhunde, Ifuro y’itanza, Ifuro y’ikomagi’ where ‘Ifuro’ is the local name given to all haplochromine species (Upper Akagera system, Burundi), ‘Icyasamyi’, ‘Ikaje’ or ‘Nyiramuhundi’ (Middle Akagera system, Rwanda).

Astatoreochromis alluaudi Pellegrin, 1904: 385 .

Astatoreochromis alluaudi alluaudi Greenwood, 1959: 174 , figs 1-3.

Astatoreochromis alluaudi occidentalis Greenwood, 1959: 174-175 , figs 2-3.

Diagnosis

Astatoreochromis alluaudi can be distinguished from A. straeleni by the possession of 4-7 anal spines (usually 5-6) vs. 3-4 (usually 3), 17-19 dorsal spines [rarely 16 (f2) or 20 (f2)] vs. 16-18 [exceptionally 19 (f1)].

Etymology

Named after Charles A. Alluaud, who collected the type specimens.

Type material

Lectotype

MNHN 1904.137 , Kavirondo Gulf , Lake Victoria, Kenya, designated by Greenwood (1959: 167).

Paralectotypes

MNHN 1904.138–139, BMNH 1904.6.281, same data as lectotype.

Specimens examined

KENYA: MNHN 1904.137, lectotype, 121.7 mm SL, Kavirondo Gulf Lake Victoria, coll. Alluaudi; BMNH 1904.6.28.1, paralectotype, 116.0 mm SL, same data as lectotype; MNHN 1904.138–139, paralectotypes, 92.8-113.8 mm SL, same data as lectotype. UGANDA: AMNH 216258 (3 specimens), 53.5-70.7 mm SL, Lake Nabugabo, coll. L.J. Chapman & C.A. Chapman, 19 May 1994; BMNH 1964.7.1.109, 85.5 mm SL, Lake Nabugabo, coll. Cambridge University; BMNH 1933.2.23.146 (11 specimens), 55.2-137.5 mm SL, Lake Nakavali, coll. E. Worthington; BMNH 1958.12.5.74-75, 63.8- 121.4 mm SL, Lake Nakavali, coll. C. Pitman; BMNH 1972.6.5.23-25, 44.8-101.6 mm SL, Lake George, coll. I. Dunn; BMNH 1933.2.23.137-141, 61.4-79.8 mm SL, Lake Edward, coll. E.Worthington; BMNH 1929.1.24.4, 87.8 mm SL, Lake Kyoga, coll. E. Worthington; BMNH 1929.1.24.278, 70.9 mm SL, Lake Kyoga, coll. E. Worthington; MRAC A5.42.P.2-5, 66.3-128.4 mm SL, Lake Kayanza, Kasese factory, coll. M. Marquet, 22 Oct. 2005; MRAC 14862-3, 95.9-111.1 mm SL, Nyanza, Lake Victoria, coll. D.E. Bayon; MRAC 90.035.P. 12, 124.2 mm SL, Gaba near Kampala, Lake Victoria, 0°15’ S – 32°28’ E, coll. D. Nyeko, 18 Mar. 1990. DEMOCRATIC REPUBLIC OF CONGO: MRAC 66003, 51.3 mm SL, Semliki River, Ishango, coll. H. Damas. TANZANIA: MRAC 81.30.P.4-5, 94.5-96.5 mm SL, Mwanza gulf, Lake Victoria, collector. HEST-Collection, 1977-1980; MRAC 90.16.P.1-3, 73.7-79.7 mm SL, Kiboko, Lake Victoria. BURUNDI: MRAC 81.P.47.512-535, 63.7-112.7 mm SL, Nyagisozi, Lake Rweru, 02°28’ S – 30°18’ E, coll. G. Ntakimazi, 6 May 1981; MRAC 93.149.P.27, 71.7 mm SL, Yaranda, maison Turquien, Lake Cohoha, 02°32’ S – 30°06’ E, coll. J. Snoeks et al., 28-29 Jul. 1993; MRAC 93.149.P.41, 83.8 mm SL, Yaranda, maison Turquien, Lake Cohoha, 02°32’ S – 30°06’ E, coll. J. Snoeks et al., 28-29 Jul. 1993; MRAC 93.149.P.28-40, 57.2-121.6 mm SL, Lake Rwihinda, ‘lac aux oiseaux’, 02°35’ S – 30°06’ E, coll. J. Snoeks et al., 9-10 Aug. 1993. RWANDA: MRAC 87.11.P. 2827- 2828, 73.6-83.4 mm SL, Lake Hago, Akagera park, coll. L. De Vos, 12 Oct. 1986; MRAC 87.P. 11.2852, MRAC 87.11.P. 2852-55, 61.5-71.9 mm SL, Lake Mpanga, ‘à l’entrée du parc Akagera’ coll. L. De Vos, 5 Nov. 1986; MRAC 86.01.P.1955, 99.2 mm SL, Lake Birengero, Akagera park, coll. L. De Vos, 14 Sep. 1985.

Redescription

Based on 87 specimens including lectotype and three paralectotypes. Morphometrics and meristics are given in Table 5 . Small to medium-sized species [maximum size, 163 mm SL ( Greenwood 1959)] with moderately compressed body; dorsal head profile fairy steeply sloping, straight or decurved, becoming concave in large individuals. Mouth horizontal or slightly oblique. Jaws equal anteriorly or lower somewhat projecting; posterior tip of maxilla reaching, or almost reaching, vertical to anterior orbital margin. Gill rakers short and stout; generally 8 or 9 [7(f1), 8 (f30), 9 (f49), 10 (f7)] on the lower limb of the first gill-arch. Flank scales around lateral line ctenoid, elsewhere cycloid; generally 29-32 longitudinal line scales, excluding the small scales on caudal fin base [26 (f1), 27(f2), 28 (f5), 29 (f8), 30 (20), 31 (f29), 32 (f14)]; cheek with 3 (f24), 4 (f57) or 5 (f5) series of scales; scales between pectoral and pelvic fins 4 (f35), 5 (f40) or 6 (f8) [rarely 3 (f1)]. Dorsal fin spines 17-19 [rarely 16 (f2) or 20 (f2)], soft rays 7 (f29) or 8 (f51) [occasionally 6 (f2) or 9 (f5)]. Anal fin spines 4-7 [(4 (f7), 5 (f63), 6 (f17) and 7 (f2)], rays 6 (f9), 7 (f56) or 8 (f20) [rarely 9 (f2)]. Pectoral fin rays 13 (f32) or 14 (f54) [rarely 15 (f1)]. Caudal fin rounded. Posteriormost teeth in outer row of upper jaw unicuspid. In small specimens, outer row teeth unequally bicuspid and relatively stout (occasionally only stout unicuspid teeth in small specimens) becoming a mixture of weakly bicuspid and unicuspid in large specimens. 28-48 outer row teeth in upper jaw and 20-42 outer row teeth in lower jaw with numbers increasing with size, 1 or 2 (occasionally 3) inner rows of small tricuspid or occasionally unicuspid teeth in both lower and upper jaws. LPJ triangular, longer than, or almost as long as, wide (LPJ width 78.1-108.5% of LPJ length); lateral teeth in the posterior rows slender and cuspidate, the central two to four (occasionally six) rows with a mixture of molariform (anterior part of the dentigerous area) and enlarged but cuspidate teeth. The specimens from Lake Victoria have a more massive LPJ and a greater proportion of molariform teeth compared to the similarly sized specimens from other lakes and rivers in the Victoria basin.

Colour pattern of live specimens

See Fig. 5 for general appearance. Anteriorly and dorsally grey yellowish, posterior-ventrally grey greenish to bluish. A dark band, continuous with lachrymal stripe, runs obliquely backwards through, or a little behind, the eye to near the gill opening. Lower jaw faint grey bluish. Fins grey yellowish, dorsal fin somewhat darker and with blackish spots on soft part; caudal fin with similar spots, pelvic blackish distally; anal fin of specimens (males and females) larger than 80 mm SL with 2-3 horizontal rows of bright orange-yellow ocelli. In specimens less than 80 mm SL, anal ocelli may be absent or hardly visible. According to Greenwood (1959), sexual dimorphism is less marked in this species than in other haplochromine cichlids and the colour pattern of breeding males resembles that of females except that the soft dorsal fin is more densely spotted, the spinous dorsal and entire caudal fin are suffused with maroon, and the cephalic marking are more intense than in females.

Colour pattern of preserved specimens

General appearance greyish-brown to brown, lighter ventrally; five or six dark transverse bars often interrupted ventrally on the flanks (lacking in some specimens). No mid-lateral band present. A vertical, or posteriorly directed, blackish bar below the eye, runs to posterior corner of mouth, occasionally extending onto lower jaw. Blackish dots arranged in interrupted horizontal rows on soft dorsal fin and in interrupted vertical rows on caudal fin; these are strongly marked in large males. Edge of fins dark to blackish, anal ocelli in males, when present dark grey.

Distribution

Known from lakes Edward, Victoria, Kyoga, George, Nakavali and Kachira, and the rivers and streams associated with these lakes, including the Semliki ( Greenwood 1959). The species has been introduced into many areas of East Africa for biological mollusc control ( Greenwood 1965b; Welcomme 1988) and now has a widespread distribution within the Victoria basin ( Kenya, Uganda & Tanzania including the Upper Akagera basin in the Bugesera depression ( Burundi & Rwanda)). Slootweg (1989) discussed the possibility of the introduction of A. alluaudi into northern Cameroon (Benue River basin), which indeed took place ( Vreven et al. 2007). There are no reports that the introduction of this species in the Congo Republic, the Democratic Republic of Congo, the Republic of Central Africa and Zambia ( Welcomme 1988) has succeeded.

Ecology

According to Greenwood (1959), A. alluaudi is not confined to a particular type of substrate and is ubiquitous in all areas where the water is less than 20 m deep. It also occurs in papyrus swamps and feeds mainly on molluscs. Ntakimazi (1985) confirmed the occurrence of the species in papyrus swamps in Lake Rweru, Bugesera depression ( Burundi & Rwanda). However, he did not find any shell fragments of snails in the gut contents of 80 specimens, but instead found a large amount of organic debris, algae, fish remains and benthic invertebrates. He concluded that A. alluaudi might be an omnivorous species that switches to the most abundant food source in its environment. He noticed, however, that the molariform teeth of the lower pharyngeal jaw are well developed, and suspected they are instrumental in crushing the exoskeletons of aquatic invertebrates and vegetal debris.

Reproduction

The species is a mouth-brooder. Most of the females caught in December 2012 in Lake Rweru in Burundi had fry in their mouth. Though its breeding period is not well documented, the species may reproduce at the end of the short rain season from November to December. Whether this is the only reproductive season cannot be determined from our data.

Figures

Fig. 5. Adult ♂♂ of Astatoreochromis alluaudi Pellegrin, 1904 caught on 15 Dec. 2012 at Kumana village, Nyagisozi zone, Lake Rweru, Upper Akagera (Rwanda), 115,3 mm SL and 100,4 mm SL not catalogued. (Photographs by GB)