Micralestes
The species of this genus always have two small conical teeth in the inner mandibular row. Inner premaxillary teeth with many cuspids aligned on one plane, which distinguishes this genus from Alestes and Brycinus. Micralestes (except M. pabrensis) is distinguished from all other Petersiini by the presence of 3-4 (vs 2) teeth in the outer row of the premaxilla (5-7 teeth total across both upper jaw elements vs 4); only the most lateral tooth of the outer row (see figure below) aligned with the interspace between inner row teeth. Body usually fusiform, the lateral line line may be complete or incomplete, humeral spot and precaudal blotch always absent..
Upper jaw in ventral view. Configuration of upper jaw teeth and alignment of lateral-most outer-row tooth with second interspace of inner row teeth (Micralestes, left) vs alignment of both outer row teeth with interspaces of inner row teeth (other Petersiini, right). Arrows indicate interspace between inner row teeth.
Synonyms
Alestes Müller & Troschel, 1844 (partim)
Brachyalestes Günther, 1864 (partim)
Petersius Boulenger, 1899 (partim)
Brycinus Cuvier & Valenciennes, 1849 (partim)
Hemigrammopetersius Pellegrin, 1929 (partim)
Alestopetersius (Alestogrammus) Hoedeman, 1951 (partim)
Micralestes (Micralestes) Hoedeman, 1956 (partim)
Phenacogrammus (Alestogrammus) Hoedeman, 1956 (partim)
Virilia Roberts, 1967
Type species
Micralestes humilis Boulenger, 1899 by subsequent designation of Jordan, 1919.
Currently, 17 species are assigned to the genus Micralestes.
Key to species.
1 Inner dentary teeth multicusid...............................................................................................................M. acutidens
Inner dentary teeth multicusid.................................................................................................................................2
2 At least 29 scales along laterla line..........................................................................................................................3
At most 28 scales along laterla line..........................................................................................................................6
3 Caudal peduncle as high as long.............................................................................................................M. congicus
Caudal peduncle elongate, its depth 1.1 to 1.75 in its length.......................................................................................4
4 Caudal peduncle depth 1.5 to 1.75 times in its length...........................................................................M. argyrotaenia
Caudal peduncle depth 1.1 to 1.4 times in its length...................................................................................................5
5 Body depth 3.4 to 3.8 times in standard length; 16 gill rakers on lower limb (ceratobranchial) of gill arch.......M. ambiguus
Body depth 3.7 to 4.2 times in standard length; 11-13 gill rakers on lower limb (ceratobranchial) of gill arch.....M. lualabae
6 4 outer premaxillary teeth.......................................................................................................................M. pabrensis
6 outer premaxillary teeth.........................................................................................................................................7
7 Outer row premaxillary teeth prominent, conical, or weakly shouldered, unicuspids..................................M. holargyreus
Outer row premaxillary teeth small and pluricuspid.....................................................................................................8
8 Eye diameter 2.2 to 2.5 times in head length and 1.5 to 1.7 times in snout length.............................................M. fodori
Eye diameter 2.6 to 3.3 times in head length and 1.0 to 1.4 times in snout length.........................................................9
9 22 to 24 scales along lateral line.............................................................................................................................10
25 to 29 scales along lateral line.............................................................................................................................11
10 13-16 branched anal fin rays; head length 3.7-3.9 in standard length; black lateral stripe, indistinct forward......M. stormsi
16-18 branched anal fin rays; head length 3.95-4.1 in standard length; lateral stripeuniformly black..................M. vittatus
11 Lateral line generally incomplete; rayed dorsal fin carmine-red in live.......................................................M. comoensis
Lateral line complete; rayed dorsal fin colourless or at least pinkish in live.................................................................12
12 Rayed dorsal fin with distinctive black apical patch.................................................................................................13
Rayed dorsal fin without black apical patch............................................................................................................14
13 Caudal fin slightly yellowish; endemic to the Cavally River...................................................................M. eburneensis
Caudal fin tinged with pink; widely distributed, never found in the Cavally River..........................................M. elongatus
14 Caudal and adipose fins bright red....................................................................................................M. occidentalis
Caudal and adipose fins colourless or, at most, pinkish..........................................................................................15
15 Well-marked band of melanophores present above anal fin.........................................................................M. schelly
No band of melanophores above anal fin................................................................................................................16
16 Head length 3.4 to 3.8 in standard length.................................................................................................M. humilis
Head length 3.75 to 4.1 in standard length................................................................................................M. sardina
Bibliography
Micralestes acutidens (Peters, 1852)
Types and type localities
Alestes acutidens Peters, 1852: 276. Type locality: “Zambèze”. Syntypes ZMHU 3576.
Petersius neglectus Boulenger, 1920: 5, 18-19. Type locality: “Poko”. Holotype MRAC 8064.
Micralestes luluae Fowler, 1930: 29-30, fig. 2. Type locality: “Lulua River, Belgian Congo”. Holotype ANSP 51715.
Micralestes brevianalis Blache & Miton, 1960: 101.. Type locality: “Lac Tchad”. Syntypes MNHN 1959-0231, 1959-0236, 1987-2108 [ex 1959-236]; CEPFL 9, 839.
Synonyms
Alestes acutidens Peters, 1852
Brachyalestes acutidens Günther, 1864
Micralestes acutidens Boulenger, 1899
Petersius neglectus Boulenger, 1920
Micralestes neglectus Myers, 1929
Micralestes luluae Fowler, 1930
Micralestes acutidens acutidens Hoedeman, 1951
Micralestes acutidens neglectus Hoedeman, 1951
Micralestes (Micralestes) acutidens acutidens Hoedeman, 1956
Micralestes (Micralestes) acutidens neglectus Hoedeman, 1956
Micralestes brevianalis Blache & Miton, 1960
Micralestes humilis (non Boulenger, 1899) Jubb, 1963
Virilia brevianalis Roberts, 1967
Common names
Afrikaans: Mbala (Namibia), Silwer-rower (Namibia, South Africa)
Arabic: Had El Asnan
Chokwe: Lutemba/Muka/Sese (Angola)
Danish: Spidstandet tetra
English: Sharptooth tetra (USA, Global), Silver robber (Namibia, South Africa, USA, Zambia, Zimbabwe), Silver tetra (USA)
Estonian: Teravhamb-kongosalmler
Finnish: Naskalialesti/Pikkukongontetra
German: Spitzzahnsalmler
Kele: Ilalanga/Lilanga/Lilengela (Democratic Republic of Congo)
Krio: Kaar/Keria/N'keria (Sierra Leone)
Limba, west-central: N'keria (Sierra Leone)
Lombo: Lilanga (Democratic Republic of Congo)
Lozi: Mbaala (Zambia)
Luba-Kasai: Mwota (Angola)
Mende: Kaar (Sierra Leone)
Not specified: Lubongo/Tshawamba (Angola)
Nyanja: Tsimbu (Malawi)
Polish: Swiecik ostrozebny
So: Gelengela (Democratic Republic of Congo)
Themne: Kerie (Sierra Leone)
Venda: Khovhenduhu (South Africa)
Zande: Pedi (Sudan)
Description
Diagnosis: body depth 3-3.5 (3-3.75) and head length 3.6-4.2 (3.5-4.2) in SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)], [types: 6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3-5/7-12 (upper jaw), 9-11/2-4 (lower jaw)]. Dorsal fin: II,8 ; (II,8). Anal fin: III,14-17 (III,14-16). Gill rakers: 13-14 (12-15). Scales: 24-27 + 1-2 (23-28) (longitudinal line); 4½ (above lateral line)/3½ (below lateral line), [types: 4½ (above lateral line)/2½-3½ (below lateral line)]; 10 around caudal peduncle. Lateral line scales: 26-29 tubes.
Maximum reported size: 90 mm SL.
Colour: a mid-lateral black band (silver when alive) starting at the posterior edge of the operculum, widening rapidely and continuing to the base of the caudal fin. Light grey fins, dorsal fin frequently dark at the tip, but sometimes lighter (less obvious).
Distribution
Widely distributed in Niger, Cross, Sanaga, Congo, Zambezi and Okavango River basins. Also in lakes Kariba, Turkana and Tanganyika (see also Faunafri).
Habitat and Ecology
Micralestes acutidens is a pelagic, potamodromous species. It forms shoals in clear, flowing or standing, open water. Common in water with fringing vegetation. It appears to co-exist with the tigerfish Hydrocynus forskalii in open water although it is heavily preyed upon by that predator, particularly those shoals of tigerfish ranging up to 45 cm in length (Bell-Cross & Minshull, 1988). Omnivorous, often feeding from surface waters on winged insects. Also takes insect larvae, crustaceans and eggs and fry of other fish (Mitchell, 1976; Bell-Cross & Minshull, 1988) (see table below).
Micralestes acutidens: diet (% occurrence) in Lake Kariba (Mitchell, 1976).
They mature after a year. A partial spawner of moderate fecundity, with usually fewer than 700 eggs per female. Shoals migrate upstream after first summer rains; breeds throughout the summer months. Used as forage fish and as bait for tigerfish and pike (Skelton, 2001).
This species has a wide distribution, with no known major widespread threats. It is therefore listed as Least Concern.
Major threats: this species is threatened by overfishing with small meshed gears.
Bibliography
Micralestes ambiguus (Géry, 1995)
Type and type locality
Micralestes ambiguus Géry, 1995: 50-52, fig. 29. Type locality: “Zaïre, Equateur Province, basin of the Oubangui, 1 km west of Bari River, a tributary of the Lua River, 63 km W. of Gemena”. Holotyê MHNG 2572,08. Paratypes MRAC 95.026.P.0003-0004; personal collection of Géry G 966 a-c, 966 d-e.
Common names
Estonian: Bari kongosalmler
Description
Diagnosis: body depth 3.4-3.8 and head length 3.60-3.85 in SL. Dental formula: [2-3/4 (upper jaw), 4 (lower jaw)]. Cuspids number: [5/4-7 (upper jaw), 5 (lower jaw)]. Dorsal fin more or less filamentous, II,8. Anal fin III,17-20. Caudal fin with extended median rays. Gill rakers: 15-20. Scales: 28-31 + 1-2 longitudinal line); 4 ½ (above lateral line)/ 1½-2 (below lateral line); 10 around caudal peduncle. Lateral line complete.
Maximum reported size: 46 mm SL.
Colour: after preservation, there is a longitudinal broad band from the opercle to the caudal peduncle, dark grey to black depending probably on the concentration of, or the time of the putting in, the formalin (before putting the specimens into alcohol); dorsal not black-tipped; adipose fin not black as in M. sardina; base of anal fin with thin oblique lines above as in M. lualabae; scales of the lateral line not marked at their centre, unlike M. congicus.
Affinities: this species is considered as a Micralestes, despite the lack of inner mandibular teeth. M. ambiguus has more scales than the 3 species from the same region, i.e. M. humilis, M. acutidens and M. stormsi. It has a relatively high number of scales (more than 25 in LL) and a lateral band, characters shared with M. sardina, and the M. argyrotaenia-congicus-lualabae assemblage. It differs from M. sardina in having more scales (28-31 vs 26-28) more branched anal fin rays (17-20 vs 16-17) and more gill-rakers (16 vs 11-12).
Distribution
Only known from the type locality, Bari River and other tributaries of the Lua River, Ubangi basin, Democratic Republic of the Congo (see also Faunafri).
Micralestes ambiguus is only known from the Bari River, Ubangui basin, Central Congo River basin. The species may be more widespread than is currently known. More information is needed on the species distribution before an assessment can be made.
Major threats: none known.
Bibliography
Micralestes argyrotaenia Trewavas, 1936
Type and type locality
Micralestes argyrotaenia Trewavas, 1936: 65-66, pl.I, fig. 1-2. Type locality: “Cunene River, Angola”. Syntype BMNH 1935.3.2:65-70
Common names
Estonian: Hõbetriip-kongosalmler
Description
Diagnosis: body depth 3.8-4 and head length 3.8-4 in SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: not indicated. Dorsal fin: II,8. Anal fin: III,16-18. Gill rakers: 13-14. Scales: 30-32 (longitudinal line); 4½ (above lateral line)/3½ (below lateral line); 10 around caudal peduncle. Lateral line complete.
Maximum reported size: 91 mm SL.
Colour: a mid-lateral black band, silvery in live specimens, begining at the posterior edge of the operculum, widening rapidly at the back, continuing up to caudal fin origin. Fins without any black marks. A mid-dorsal black line.
Affinities: see comparative table of affinity with M. lualabae.
Distribution
Cunene River basin, Angola (see also Faunafri).
Only known from the Kunene River system. No obvious known threats. More comprehensive surveys required to confirm the true extent of its distribution. It is therefore listed as Least Concern.
Major threats: none known.
Bibliography
Micralestes comoensis Poll & Roman, 1967
Type and type locality
Micralestes comoensis Poll & Roman, 1967: 179-182, fig. 1-2. Type locality: “Comoé”. Holotype: MRAC141924. Paratypes: MNHN 1967-0667; MRAC 141941, 141925-141928, 141929-141936, 141937-141940, 153172-153182, 153183-153186
Common names
Estonian: Komoé kongosalmler
Description
Diagnosis: body depth 3.05-3.45 and head length 3.4-3.85 in SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3/4-7 (upper jaw), 3-5/1 (lower jaw)]. Dorsal fin: II,8. Anal fin: III,16-18. Gill rakers: 12-14. Scales: 25-29 + 1-2 (longitudinal line); 4½ (above lateral line)/3½ (below lateral line); 10 around caudal peduncle. Lateral line scales 16-29 tubes.
Maximum reported size: 68 mm SL.
Colour: a mid-lateral black band, silvery in live specimens, begining behind the operculum and widening rapidly at back, continuing up to the caudal fin origin. Fins without any black marks.
Affinities: this species is closed to M. occidentalis. Poll (1967) estimates that these two species may be synonymous. But the lack of black marks on the dorsal fin and the fact that the lateral line is frequently shortened (sometimes very shortened) lead him to hesitate about such a synonymy.
Distribution
Only known from the Upper Comoé River, Côte d'Ivoire and Burkina Faso (see also Faunafri).
The species is known from Burkina Faso and Côte d'Ivoire. The extent of occurrence and area occupancy thresholds are estimated at less than 20,000 km² and less than 2,000 km², respectively. Possible decline in its habitat quality may be due to drought and deforestation. The species restricted to only two or three locations, and it therefore qualifies for a Vulnerable status.
Major threats: drought, pollution and deforestation threaten this species.
Bibliography
Micralestes congicus Poll, 1967
Type and type locality
Micralestes congicus Poll, 1967: 44, 46-48, fig. 5. Type locality: “Bokuma”. Holotype: MRAC 96582. Paratypes: MRAC 96583-96584, 153747.
Common names
Estonian: Harilik kongosalmler
Description
Diagnosis: body depth 3.5-3.95 and head length 3.7-3.85 SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3-5/5-7 (upper jaw), 3-5/1 (lower jaw)]. Dorsal fin: II,8. Anal fin: III,19-21. Gill rakers: 13-14. Scales 29-30+2 (longitudinal line); 4½ (above lateral line)/3½ (below lateral line); 10 aorund caudal peduncle. Lateral line scales: 30-32 tubes (see table below).
Micralestes congicus: morphometric and meristic data.
Maximum reported size: 82 mm SL.
Colour: a mid-lateral black band, silvery in live specimens, begining behind the operculum and widening rapidly at the back, continuing up to the caudal fin origin. Lateral line scales darkened to their base. Fins are greyish without any black blotches.
Affinities: see comparative table of affinity with M. lualabae.
Distribution
Only known from the Ruki River drainage (middle Congo River basin) in Democratic Republic of the Congo (see also Faunafri).
The species is widespread or without major threats throughout the Central Africa assessment region and is assessed as Least Concern.
Major threats: none known.
Bibliography
Micralestes eburneensis Daget, 1964
Type and type locality
Micralestes eburneensis Daget, 1964: 590-591. Type locality: “Cavally à Toulépleu”. Holotyê: MNHN 1964.270. Paratypes: MNHN 1964.271.
Synonyms
Micralestes eburneensis Daget, 1964:
Rhabdalestes eburneensis Poll, 1967
Hemigrammopetersius (Rhabdalestes) eburneensis Géry, 1977
Common names
Estonian: Vandliranniku kongosalmler
Description
Diagnosis: body depth 3.05-3.5 (3.3-3.75) and head length 3.55-3.9 (4.15-4.3) in SL. Dental formula: [4-6/8 (upper jaw), 8/10-2 (lower jaw)], [type: 6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3-5/3-7 (upper jaw), 3-7 (lower jaw)]. Dorsal fin II,8 (II,8-9) located at vertical through pelvic-fin insertion. Anal fin III,15-17 (III,16-18). Gill rakers: 13-15 (13-15). Scales: 22-25+2 (27-29) (longitudinal line), 4½-5½ (above lateral line)/3½ (below lateral line), [type: 4½ (above lateral line)/3½ (below lateral line)], 10 around caudal peduncle. Lateral line scales: 22-26 (27-29) tubes.
Maximum reported size: 61 mm SL.
Colour: a mid-lateral black band more visible at the back. The bottom of the anal fin is edged with black. The tip of the longest rays of the dorsal fin has a black mark.
Remark: according to Poll (1967): "Our specimens, except 2 paratypes, lack internal mandibulary teeth. Indeed, out of 18 specimens from Cavally River basin (coll. D. Thys van den Audenaerde), we have never seen cone-shaped internal teeth at the lower jaw. These teeth have been noted by Daget (1964) as relatively underdeveloped. That is the reason why we think some populations may lack it? Another great diagnostic difference we noted consists in the variability of upper external teeth: 4-6. Such a variability as the lack of internal teeth are peculiar to genus Rhabdalestes”.
Distribution
This species seems to be endemic to the Cavally River, but it may be exist in Cess (Nipoué) River, Western Côte d'Ivoire (see also Faunafri).
This species seems to be endemic to the Cavally River, Côte d'Ivoire. But may exist in the Nipoue. There are no known major threats to the species. Due to its very restricted range, we can qualify the species as Near Threatened as any identified threat will trigger listing as a threatened species under Criteria B and/or D.
Major threats: no current threats known.
Bibliography
Micralestes elongatus Daget, 1957
Type and type locality
Micralestes acutidens elongatus Daget, 1957. 126-128, fig. 11. Type locality: “Bougouriba”. Holotype: MNHN 1956.106. Paratypes: MNHN 1960.409, 1960.410, 1960.411, 1960.412, 1960.413.
Synonyms
Micralestes acutidens elongatus Daget, 1957
Micralestes elongatus Poll, 1967
Virilia elongatus Roberts, 1967
Common names
English: Elongated robber/Elongated Turkana robber (Kenya), Sharptooth tetra (Global)
Estonian: Sale kongosalmler
Finnish: Siroalesti
Hausa: Kawara (Nigeria)
Ijo: Ewere (Nigeria)
Kanuri: Sange (Nigeria)
Nupe: Kurangi (Nigeria)
Description
Diagnosis: body depth 3.45-3.95 (3.5-4) and head length 3.6-4 (3.6-4.25) in SL. Mouth terminal, upper lip prominent, depth of lower jaw about 1.5 that of upper jaw.Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)], [type : 6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3-5/6-7 (upper jaw), 5-7/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,16-19 (III,16-17). Gill rakers: 11-14 (13). Scales: 25-28+1-2 (27-29) (longitudinal line); [4½ (above lateral line)/3½ (below lateral line)], [type: 4½ (above lateral line)/3½ (below lateral line)]; 10 around caudal peduncle. Lateral line complete, 22-30 tubes ultimate canal-bearing scale terminal.
Maximum reported size: 60 mm SL.
Colour: like M. acutidens (Peters), including a black mark of the dorsal fin tip.
Affinities: most similar to M. acutidens, from which it differs in the presence of conical, monocuspid (vs multicuspid) inner dentary teeth, inner premaxillary and outer dentary with fewer cusps, and a slightly more slender body
Distribution
Found in most Sahelo-Sudanese basins of West Africa (Senegal, Volta, Niger, Chad), in the Cross River basin, in Kenya, in Sudan and in Ethiopia (see also Faunafri).
IUCN assessment
Not evaluated
Bibliography
Micralestes fodori Matthes, 1965
Type and type locality
Micralestes fodori Matthes, 1965: 178-181, fig. 1. Type locality: “Lake Fwa”. Holotype: MRAC 140901. Paratypes: MRAC 140903-140906, 71380.
Common names
Estonian: Fodori kongosalmler
Description
Diagnosis: body depth 3.6-4 (3.75-4.6) and head length 3.45-3.8 (3.5-3.9) in SL. Dental formula: [6/8 (upper jaw), 8/0-2 (lower jaw)], [type: 6/8 (upper jaw), 6-8/0-2 (lower jaw)]. Cuspids number: [1-3/3-5 (upper jaw), 2-6/1 (lower jaw)]. Dorsal fin: II,8 (II-III,8). Anal fin: III,17-19 (III,17-19). Gill rakers: 11-13 (11-14). Scales: 25-27 + 1-2 (24-27) (longitudinal line); [4½ (above lateral line)/3½ (below lateral line)], [type: 4½ (above lateral line)/3½ (below lateral line)]; 10 (9-11) around caudal peduncle. Lateral line complete.
Maximum reported size: 42 mm SL.
Colour: a mid-lateral black band extending from posterior edge of the operculum to caudal-fin origin, without any differences in width at the back. Anal-fin base darkened. Fins are greyish. Dorsal longitudinal rows of scales marked with a small black line in male.
Distribution
Only known from Lake Fwa(Sankuru drainage, middle Congo River basin) in Democratic Republic of the Congo (see also Faunafri).
The species is widespread or without major threats throughout the Central Africa assessment region and is assessed as Least Concern.
Major threats: none known.
Bibliography
Micralestes holargyreus (Günther, 1873)
Types and type localities
Alestes holargyreus Günther, 1873: 144. Type locality: “Boma”. Syntypes: BMNH 1873.7.28:19-23.
Alestes brevipinnis Perugia, 1891: 975-976. Type locality: “Vivi, Congo”. Syntypes: MSNG 9248.
Synonyms
Alestes holargyreus Günther, 1873
Alestes brevipinnis Perugia, 1891
Micralestes holargyreus Boulenger, 1899
Micralestes acutidens holargyreus Hoedeman, 1951
Micralestes (Micralestes) acutidens holargyreus Hoedeman, 1956
Common names
Estonian: Hõbedane kongosalmler
Description
Diagnosis: body depth 2.6-2.9 (2.65-3) and head length 3.5-3.8 (3.5-4) in SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)], [type: 6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [1/6-9 (upper jaw), 5-7/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,18-19 (III,17-19). Gill rakers: 11-13 (12-13). Scales: 23-25 + 1-2 (23-25) (longitudinal line); [4½ (above lateral line)/3½ (below lateral line)], [type: 4½ (above lateral line)/3½ (below lateral line)]; 10 around caudal peduncle. Lateral line scales: 24-27 tubes.
Maximum reported size: 80 mm SL.
Colour: no dark mark visible in preserved specimens, except the base of the scales of middle flanks. Fins without any black marks. A lateral silvery band in live specimens.
Distribution
Marine lower Congo and lower Congo River in Democratic Republic of the Congo (see also Faunafri).
Micralestes holargyreus is only known from Boma, Lower Congo River, Democratic Republic of the Congo. One dubious record has been made from the Dja River, Central Congo River basin. The species may be more widespread than is currently known. More information is needed on the species distribution before an assessment can be made.
Major threats: none known.
Bibliography
Micralestes humilis Boulenger, 1899
Types and type localities
Micralestes humilis Boulenger, 1899: 87, pl. XXXVI, fig. 4. Type locality: “Kutu”. Holotype: MRAC 805.
Petersius woosnami Boulenger, 1907: 487. Type locality: “Aruwimi River”. Syntypes: BMNH 1907.4.20:35-46.
Synonyms
Micralestes humilis Boulenger, 1899
Petersius woosnami Boulenger, 1907
Micralestes woosnami Myers, 1929
Micralestes acutidens humilis Hoedeman, 1951
Micralestes (Micralestes) acutidens woosnami Hoedeman, 1956
Micralestes stormsi (non Boulenger, 1902) Daget, 1966
Common names
Estonian: Helklev kongosalmler
Finnish: Kuultoalesti
German: Afrikanischer Rotflossensalmler
Ijo: Ewere (Nigeria)
Kele: Ilalanga/Lilanga/Lilengela (Democratic Republic of the Congo)
Lombo: Lilanga (Democratic Republic of the Congo)
So: Gelengela (Democratic Republic of the Congo)
Description
Diagnosis: body depth 3.2-4 (3.5-4) and head length 3.45-3.8 (3.5-4) in SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)], [type: 6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [4-6/5-9 (upper jaw), 6-8/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III-IV,14-18 (III,16-19). Gill rakers: 10-13 (14-15). Scales: 24-27 + 1-2 (27-30) (longitudinal line); [4½ (above lateral line)/3½ (below lateral line)], [type: 4½ (above lateral line)/3½ (below lateral line)]; 10 around caudal peduncle. Lateral line scales: 23-29 tubes.
Maximum reported size: 106 mm SL.
Colour: black lateral band from posterior opercular margin to caudal fin base and extending onto proximal portion of median rays, band underlain by broad silver pigment in life. Width of band and density of pigmentation increase caudal and greatest at vertical through anal fin origin. Adipose fin with pigmented margin in larger individuals. Scales of flank often with concentration of dark pigment along anterior margin. Fins generally hyaline to moderately dusky, otherwise unpigmented.
Affinities: M. humilis is most similar and possibly conspecific with M. stormsi Boulenger, 1902 and M. sardina Poll, 1938. Apart from colouration, it is distinguished from the latter two species on the basis of slight differences in overlapping features. From M. stormsi, it is distinguished on the basis of greater number of scales in the longitudinal series (25-27, vs 22-24 in M. stormsi) and from M. sardina by a slightly greater head length (26-29% SL, vs 24-27% SL in M. sardina). Furthermore, the presence of dark pigmentation along the base of the flank scales, considered by Poll (1967) and others as characteristic of M. humilis, was observed to be variably preserved in the material examined in this study. These species are distributed broadly in the Congo basin and material referable to all three was observed in the Lower Guinea region. However, such small differences are of dubious diagnostic utility in light of insufficient knowledge of intraspecific and geographic variation in these species. At present, it seems most reasonable to refer all to the older available name, M. humilis.
Distribution
Chad, Niger (Benue River), Cross, Ntem, Ogowe, Congo and Zambezi River basins. Also in lakes Chad, Mweru and Tanganyika (see also Faunafri).
This species has a wide distribution, with no known major widespread threats. It is therefore listed as Least Concern. It has also been assessed regionally as Least Concern for central Africa. In western Africa, this species has wide distribution within Nigeria and Chad. As it is only known from five locations it might qualify as Vulnerable D2. However, as one of the locations is subject to active protection (Cross River National Park) it is assessed as Near Threatened.
Major threats: habitat degradation, especially due to oil exploration and habitat alteration following changes in water flow and long-term climatic change. Proliferation of the invasive Typha sp. has had a major impact through loss of habitat. It also has commercial value as an aquarium fish.
Bibliography
Micralestes lualabae Poll, 1967
Type and type locality
Micralestes lualabae Poll, 1967: 44-45, fig. 6. Type locality: “Kindu, River Lualaba”. Holtype: MRAC 70201. Paratypes: MRAC 70194-70200, 70202-70218, 70219-70227, 70228-70233.
Common names
Estonian: Lualaba kongosalmler
Description
Diagnosis: body depth 3.7-4.2 and head length 3,75-4 in SL. Dental formula: [5-7/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3-4/5-9 (upper jaw),4-7/1(lower jaw)]. Dorsal fin: II,8. Anal fin: III,17-19. Gill rakers: 11-13. Scales: 29-33 +2 (longitudinal line); 4½ (above lateral line)/3½ (below lareral line); 10-11 around caudal peduncle. Lateral line scales: 31-35 (see table below).
Micralestes lualabae: morphometric and meristic data.
Maximum reported size: 92 mm SL.
Colour: a mid-lateral black band, silvery in live specimens, begining at the posterior edge of the operculum, widening rapidly and extending up to the caudal-fin origin. Fins are slightly greyish.
Affinities: this species belongs to Micralestes group with more than 28 longitudinal line scales (29 only being exceptional in Micralestes comoensis Poll & Roman). Poll (1967a) established a comparative table for these species with numerous scales only known from Congo and Cunene basin (see table below). M. congicus is easily distinguishable thanks to anal-fin rays and the large depth of the caudal peduncle. M. lualabae and M. argyrotaenia are related to each other although they are geographically very faraway (Upper River Congo and River Cunene). A difference in anal fin rays mean may be noted, it is the same for differences in caudal peduncle proportions and above all, a difference in the number of gill rakers.
Main morphological differences between M. argyrotaenia, M. congicus and M. lualabae.
Distribution
Lower Congo River in Republic of Congo, and the middle Congo River, Ruki, Itimbiri, Aruwimi, Lindi-Tshopo, Wagenia Falls and Lualaba in Democratic Republic of the Congo (see also Faunafri).
The species is widespread or without major threats throughout the Central Africa assessment region and is assessed as Least Concern.
Major none known.
Bibliography
Micralestes occidentalis (Günther, 1899)
Types and type localities
Petersius occidentalis Günther,1899: 731, pl. XLV, fig. B. Type locality: “Kotchwah River (Gold Coast)”. Syntypes: BMNH 1899.12.22:32-36.
Micralestes voltae Roman, 1966: 67-70, pl. III, fig. 5-6. Type locality: “Rivière Niame affluent du Kou (Haute Volta)”. Holotype: MRAC 141158. Paratypes: MRAC 141160-141166, 141167-141179, 141180-141192.
Synonyms
Petersius occidentalis Günther,1899
Micralestes occidentalis Myers, 1929
Hemigrammepetersius occidentalis Pellegrin, 1933
Micralestes acutidens occidentalis Hoedeman, 1951
Micralestes (Micralestes) acutidens occidentalis Hoedeman, 1856
Micralestes voltae Roman, 1966
Common names
Estonian: Tuliuim-kongosalmler
Finnish: Tulialesti
German: Afrikanischer Salmler
Description
Diagnosis: body depth 3.1-3.3 (3-3.25) and head length 3.9-4.1 (3.5-4) in SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)], [type: 6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3/5-7 (upper jaw), 3-6/1 (lower jaw)]. Dorsal fin: II,8 (III,8). Anal fin: III,18-19 (III,18-21). Gill rakers: 12-13 (12-13). Scales: 25-26 + 2 (24-27) (longitudinal line); [4½ (above lateral line)/3½ (below lateral line)], [type : 4½ (above lateral line)/2½ (below lateral line)]; 10 (10) around caudal peduncle. Lateral line scales: 25-27 tubes (complete or sometimes shortened).
Maximum reported size: 65 mm SL.
Colour: a mid-lateral black band (bright in live specimen). There is a basal line at the anal fin. Dorsal fin often darkened to its tip and to its base.
Distribution
Occurs in all basins of Côte d'Ivoire as well as in some basins of Ghana, Liberia and Sierra Leone. A savannah-dwelling form of this species inhabits the upper reaches of the Niger and the Volta Rivers (see also Faunafri).
This species has a wide distribution with no known major widespread threats.
Major threats: none known.
Bibliography
Micralestes pabrensis (Roman, 1966)
Type and type locality
Phenacogrammus pabrensis Roman, 1966: 71-76, pl. IV, fig. 7-8. Type locality: “Pabré, basin de la Volta Blanche”. Holotype: MRAC 141261. Paratypes: MRAC 141265-141266, 141267-141278, 141332-141358, 141359-141365, 141366-141378, 141379-141397.
Synonyms
Phenacogrammus pabrensis Roman, 1966
Virilia pabrensis Roberts, 1967
Micralestes pabrensis Paugy, 1990
Noms communs
Estonian: Pabré kongosalmler
Description
Diagnosis: body depth 3.15-3.55 (3.05-3.6) and head length 3.85-4.3 (3.85-4.05) in SL. Dental formula: [4/8 (upper jaw), 8/2 (lower jaw)], [type: 4/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3/3-5 (upper jaw), 3-5/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,15 (III-IV,13-15). Dorsal and caudal fins without any extended rays. Gill rakers: 13-15 (11-15). Scales: 25-27 + 1-2 (25-28 + 1-2) (longitudinal line); [4½ (above lateral line)/3½ (below lateral line)], [type: 4½ (above lateral line)/3½ (below lateral line)]; 10 (10) around caudal peduncle. Lateral line scale: 7-8 (6-10) tubes.
Maximum reported size: 52.5 mm SL.
Colour: a blackish longitudinal band located at body mid-depth, without any extension along caudal rays. Anal fin base is darkened too. Fins are hyalin.
Distribution
Known only from the Volta and Pra basins (Ghana and Burkina Faso) (see also Faunafri).
This species is known from numerous locations in Burkina Faso (whole upper Volta basin) and Ghana (Pra river) and some coastal basins (with a large EOO and AOO). It is impacted by deforestation and invasive species in parts of its range. The species is assessed as Least Concern, but it needs to be monitored due to the threats.
Major threats: the main threats of this species are invasive weeds, sedimentation, deforestation and drought in its area of distribution.
Bibliography
Micralestes sardina Poll, 1938
Type and type locality
Micralestes sardina Poll, 1938: 411-413, fig. 12. Type locality: “Kandulu, near Sakiana”. Lectotype: MRAC 50040. Paralectotype: MRAC 50041-50051.
Common names
Estonian: Sardiin-kongosalmler
Description
Diagnosis: body depth 3.5-3.95 (3.65-4.2) and head length 3.75-4.1 (3.8-4.25) in SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)], [type: 6/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [4-5/6-7 (upper jaw), 4-8/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,16-17 (III,15-17). Gill rakers: 11-12 (9-10). Scales: 26-28 + 1-2 (27-30) (longitudinal line); [4½ (above lateral line)/3½ (below lateral line)], [ type: 4½ (above lateral line)/3½ (below lateral line)]; 10 around caudal peduncle. Lateral line scales 28-30 tubes.
Maximum reported size: 95 mm SL.
Colour: a mid-lateral black band, silvery in live specimens, beginning at the posterior edge of the operculum and widening at the back, continuing up to the caudal-fin origin. Body scales often blackened to their base, particularly those of the lateral line. Fins without any black mark, sometimes greyish.
Distribution
Middle Congo River and Lualaba River in Democratic Republic of the Congo, and Mweru-Luapula and Bangweulu-Chambeshi areas (upper Congo River basin) in Democratic Republic of the Congo and Zambia (see also Faunafri).
Remark / synonymy
Micralestes sardina is proposed as junior synonym of Micralestes humilis by Decru et al., 2017.
Micralestes humilis is a widespread species that occurs throughout the whole Congo basin. Elsewhere, it is known from Lower Guinea (Cross, Ntem, and Ogowe rivers), the Niger, and Zambezi rivers and lakes Chad, Mweru, and Tanganyika (Paugy & Schaefer 2007). Micralestes sardina on the other hand is only known from the Upper Congo, from which it was also described (Kandulu, Luembe River, 12°46′S, 28°38′E), and a few records from the Middle Congo near Kisangani (RMCA collection). Both species are only slightly different, based on some overlapping characteristics (Poll 1967a): Micralestes humilis is said to have a larger head (3.4-3.8 vs. 3.75-4.1 times in the standard length) and fewer lateral line scales (24-27 vs. 26-28) than M. sardina. However, upon examining the types and 90 other specimens, no differences between the two species could be found, not even for the two diagnostic features according to Poll (1967a). Specimens of both M. humilis and M. sardina had a range of 22-28 lateral line scales and highly overlapping values for head length (as %SL). Head length was found to be negatively allometric. As the types of M. sardina are larger than the holotype of M. humilis (67.5-70.7 vs. 42.0 mm), the larger head length in M. humilis according to Poll (1967a) could be explained by this negative allometry. The number of lateral line scales of the holotype of M. humilis (27) fell into the range of the types of M. sardina (26–29). In addition to allometry, a possible wrong allocation of specimens to the species could also have blurred the delineation of the two species. However, even when taking only specimens from the type region of both species into account, a very high overlap remained. As such, M. sardina is hereby considered a junior synonym of M. humilis.
Although there are threats in the southern distribution of the species, it is relatively widespread and is therefore Least Concern.
Major threats: none known.
Bibliography
Micralestes schelly Stiassny & Mamonekene, 2007
Type and type locality
Micralestes schelly Stiassny & Mamonekene, 2007: 21-24, fig. 1-6. Type locality: “Democratic Republic of Congo, Bas Congo Province, Congo River main channel near Inga at point 50 (5°31.69’ S 13°36.47’ E)”. Holotype: AMNH 240662. Paratrypes: AMNH 239518, MRAC 2007.26.P.0001-0002, MNHN 2007-1629, ZSM 33982, MCZ 166773, CU 93431.
Common names
Estonian: Schelly kongosalmler
Description
Diagnosis: a member of a clade of small alestid fishes characterized by the combination of the absence of a supraorbital bone, and the presence of a deep-lying midlateral stripe extending along the body onto the caudal peduncle, a band of chromatophores above the anal fin, and a small pair of inner row symphyseal teeth on the dentary. Micralestes schelly is distinguished from all putative congeners in having an elevated vertebral count of 38-40 (mean 39) versus 34-36 (mean 35) vertebrae. Additionally the species is characterized by the presence of 4-6 outer row premaxillary teeth with a majority of specimens (23 of 40) with only four outer row teeth implanted in an alternating pattern with respect to the anterior inner row premaxillary teeth. Mature males are further diagnosed by live coloration, which is dominated by a broad, blue-green iridescent midlateral band extending from behind the opercle to the base of the caudal fin, and by a marked expansion of the band of black chromatophores above the anal fin. See main characters in the table below.
Micralestes schelly: morphometric and meristic data.
Maximum reported size: 49 mm SL.
Color: in alcohol: base body coloration yellowish brown dorsally and laterally, yellow-orange ventrally. A darkly pigmented, deep-lying midlateral stripe extends from posterior margin of opercle to base of caudal fin. Well-marked band of dark melanophores present above anal fin. Pectoral and pelvic fins pale yellow. Adipose fin tipped in black. Dorsal and caudal fins somewhat dusky. Anal fin of females dusky proximally, in males pigmentation is somewhat expanded distally in posterior portion of fin.
In life: in life a broad, blue-green iridescent midlateral band covers the lateral flanks and tail from behind the opercle to the base of the caudal fin. This iridescent band overlies and obscures the deep lying midlateral stripe evident in preserved specimens. Above and below the midlateral band the body is silvery white. Numerous melanophores are present on the head and opercle, and scattered over the body with a concentration around lateral scale margins. An expanded band of black melanophores reaching to the lateral line is present above anal fin. Dorsal fin and pectoral fins are dusky gray; adipose fin is pale gray with a dark distal margin. Caudal fin is dusky gray at its base with a median dark band extending to mid-fork, distally the fin is dusky gray and medially each fin fork is deep crimson red. Anterior and distal margins of the anal fin are white, while the remainder of the fin is jet black. Pelvic fins are white. Iris is silvery white with a small red patch dorsally. Unfortunately no female specimens were collected during a recent site visit and female life coloration remains unknown.
Affinities: recent collections in the region allow to document the presence of six Micralestes in the stretch of the lower Congo River from Pool Malebo to Boma near the river’s mouth, and as an aid for field identification Stiassny & Mamonekene (2007) provide an illustrated key to those species:
1 Teeth with numerous small cusps, first inner row premaxillary tooth with 10-12 cusps (fig. 1A). Inner row tooth pair on dentary
usually multicuspid (fig. 3A). Dorsal fin with distinctive black apical patch (fig. 2A)...........................................M. acutidens
Teeth with fewer cusps, first inner row premaxillary tooth with 6-8 cusps (fig. 1B). Inner row tooth pair on dentary invariably
unicuspid (fig. 3B).Dorsal fin without black apical patch (fig. 2B)........................................................................................2
2 23-28 scales in longitudinal series from opercle to point of caudal flexure (fig. 3A)..............................................................3
29-33 scales in longitudinal series from opercle to point of caudal flexure (fig. 2B)..............................................M. lualabae
3 Outer row premaxillary teeth small and tricuspid or quadricuspid (fig. 1A)..........................................................................4
Outer row premaxillary teeth prominent, conical, or weakly shoultered, unicuspids (fig. 1B)...........................M. holargyreus
4 Median cusp of symphyseal teeth on dentary less than twice the height of adjacent cusps (fig. 3A). 24-28 scales in
longitudinal series from opercle to point of caudal flexure. Adipose fin black distally, pale proximally (fig. 2A)........................5
Median cusp of symphyseal teeth on dentary elongate and more than twice the height of adjacent cusps (fig. 3B). 23-24
scales in longitudinal series from opercle to point of caudal flexure. Adipose fin black (fig. 2A).............................M. stormsi
5 Relatively gracile, body depth 3.8-4.2 into standard length. Adipose eyelid restricted posteriorly to orbital margin (fig. 2A)
..................................................................................................................................................................M. humilis
Relatively deep-bodied, body depth 3.0-3.8 into standard length. Adipose eyelid extending posterodorsally over postorbital
region (fig. 2B)..............................................................................................................................................M. schelly
Habitat
Micralestes schelly was collected over a sand and gravel substrate in the main channel of the Congo River amongst large rock slabs of up to 4 m high thrusting upward at angles of 60-70 degrees, in pools up to 2 m deep (Stiassny & Mamonekene 2007). It is a pelagic species.
Distribution
Only known from the type locality on the lower Congo River near Inga, in Democratic Republic of the Congo (see also Faunafri).
Micralestes schelly is only known from the Lower Congo River basin, near Inga. The species has only recently been described and could be more widespread than is currently known. More information is needed on the species distribution before an assessment can be made.
Major threats: no information available.
Bibliography
Micralestes stormsi Boulenger, 1902
Types and type localities
Micralestes stormsi Boulenger, 1902: 265, pl. XXVIII, fig. 1-2. Type locality: “Lindi River (Upper Congo)”. Syntypes: ISNB 8.
Alestes stolatus Boulenger, 1920: 17. Type locality: “Poko”. Syntypes: MRAC 8050.
Synonyms
Micralestes stormsi Boulenger, 190
Alestes stolatus Boulenger, 1920
Alestopetersius (Alestogrammus) stormsi Hoedeman, 1951
Phenacogrammus (Alestogrammus) stormsi Hoedeman, 1959
Brycinus stolatus Géry, 1958
Common names
Estonian: Stormsi kongosalmler
Finnish: Kongonalesti
German: Echter Roter Kongosalmler
Kele: Ilalanga/Lilanga/Lilengela (Democratic Republic of the Congo)
Lombo: Lilanga (Democratic Republic of the Congo)
Polish: Swiecik niebieskopregi
So: Gelengela (Democratic Republic of the Congo)
Description
Diagnosis: body depth 2.9-3.9 (3.5) and head length 3.7-3.9 (4) in SL. Dental formula: [6/8 (upper jaw), 8/2 (lower jaw)], [type: 8/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [5-6/6-8 (upper jaw), 5-8/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,15-16 (III,15-16). Gill rakers: 10-12 (12-13). Scales: 23-24+1-2 (22-24) (longitudinal line); 4½ (above lateral line)/3½ (below lateral line), [type : 4½ (above lateral line)/3½ (below lateral line)]; 10 around caudal peduncle. Lateral line scales: 24-26 tubes.
Maximum reported size: 100 mm SL.
Colour: a mid-lateral black band, not well marked, in front of pelvic-fin insertion, more visible at the back, silvery in live specimens. Fins without any black marks.
Habitat
Micralestes stormsi is a pelagic species. It inhabits lakes (Eccles 1992) but is most often found in the lower reaches of streams and rivers.
Distribution
Widely distributed in the Congo River basin in Central African Republic and Democratic Republic of the Congo. Also reported from the Rusizi and Malagarasi in Burundi, the Lake Chad basin in Central African Republic and the Lake Tanganyika basin in Tanzania (see also Faunafri).
This species has a wide distribution, with no known major widespread threats. It is therefore listed as Least Concern. It has also been assessed regionally as Least Concern for central and eastern Africa.
Major threats: this species is threatened by water turbidity due to erosion on river basins - a consequence of agriculture extension.
Bibliography
Micralestes vittatus (Boulenger, 1917)
Type and type locality
Alestes vittatus Boulenger, 1917: 363-364. Type locality: “Lufako River at Pala”. Syntypes: MRAC 11547-11548, 14323-14324.
Synonyms
Alestes vittatus Boulenger, 1917
Brycinus vittatus Myers, 1929
Micralestes stormsi (non Boulenger) Poll, 1946
Micralestes vittatus Poll, 1967
Common names
Estonian: Vööt-kongosalmler
Description
Diagnosis: body depth 3.35-3.6 (3.5-3.65) and head length 3.95-4.1 (4-4.25) in SL. Dental formula: [6/8-9 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3-5/5-8 (upper jaw), 5-7/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,16-18 (III,15-16). Gill rakers: 11-12 (12-13). Scales: 22-23+2 (23-24) (longitudinal line); 4½ (above lateral line)/3½ (below lateral line), [type: 4½ (above lateral line)/3½ (below lateral line)]; 10 around caudal peduncle. Lateral line scales: 24-25 tubes.
Maximum reported size: 90.5 mm SL.
Colour: a mid-lateral black band, silvery in live specimens, beginning at the posterior edge of the operculum and widening rapidly at the back, continuing up to the caudal-fin origin. Fins without any black marks.
Affinities: Micralestes vittatus differs from M. stormsi in a smaller head, a greater number of anal-fin rays, scales a little less numerous. Poll (1967) restores the name of this species, he wrongly declared as synonym (Poll, 1946). Indeed, anal-fin rays are in this case more numerous and colour patterns are not the same.
Distribution
Endemic to Lake Tanganyika, present in Lufuko River at Mpala and in Lukuga River outflow (see also Faunafri).
Reported in the literature as being endemic to the Lake Tanganyika basin (Eccles 1992), but no collection records were obtained from Tanzania.
Major threats: no information available.
Bibliography
