Alestopetersius
Alestopetersius Hoedeman, 1956
Body depth 2.4-4, head length is 3.35-3.95 of the standard length. Prominent lower jaw. Parietal fontanel present. Dental formula [4/8-10 (upper jaw), 8-11 (lower jaw)], without any lower inner teeth. Outer premaxillary teeth alternating with inner row. Cuspids number: upper jaw, outer row from 3 to 6, inner row from 3 to 9; lower jaw , outer row from 3 to 9. Unpaired fins more or less filamentous. Dorsal fin generally filamentous, II, 8. Anal fin III, 17-23. Gill rakers on the lower limb of the first gill arch 13-27. Longitudinal line scales 22-42 + 1-2; transversal line scales [5½-8½ (above lateral line), 2½-4½ (below lateral line)]; scales around caudal peduncle 10-14. Lateral line complete or shortened of 1-2 tubes.
Colour pattern: a black humeral spot or not. A blackish lateral band or a black lateral line more visible at the back or an oblong spot oblong mark along caudal peduncle continuing along median rays of the caudal fin. Dorsal, caudal and anal fins are greyish to blackish.
Recently (Mbimbi Mayi Munene & Stiassny, 2012), it was proposed the synonomy of Duboisialestes with Alestopetersius. Results from an analysis of the relationships and generic composition of the Alestidae provide support for the monophyly for Alestopetersius inclusive of the members of the genus Duboisialestes, which are, therefore, placed into synonomy with the former.
Main morphological differences between the ten Alestopetersius species.
Synonyms
Petersius Boulenger, 1899 (partim)
Micralestes Boulenger, 1899 (partim)
Hemigrammopetersius Pellegrin, 1929 (partim)
Alestopetersius (Rhabdopetersius) Hoedeman, 1951 (partim)
Alestopetersius (Petersialests) Hoedeman, 1951 (partim)
Alestopetersius (Nannopetersius) Hoedeman, 1951 (partim)
Duboisialestes Hoedeman, 1951
Micralestes (Micralestes) Hoedeman, 1951 (partim)
Phenacogrammus (Rhabdopetersius) Hoedeman, 1956 (partim)
Phenacogrammus (Petersialestes) Hoedeman, 1956 (partim)
Hemigrammopetersius (Alestopetersius) Géry, 1977
Type species Alestopetersius hilgendorfi
Petersius hilgendorfi Boulenger, 1899 by original designation of Hoedeman, 1956.
Currently, ten species are assigned to the genus Alestopetersius.
Key to species.
1 13-15 scales around the caudal peduncle..................................................................................................A. hilgendorfi
10-12 scales around the caudal peduncle......................................................................................................................2
2 At least 24 gill rakers on lower limb (ceratobranchial) of first gill arch.........................................................A. leopoldianus
At most 20 gill rakers on lower limb (ceratobranchial) of first gill arch................................................................................3
3 Middle caudal fin rays prolonged in the males; a dark lateral stripe up to the tips of these rays...........................................4
Middle caudal fin rays not prolonged in the males; a very narrow lateral stripe or no lateral striê..........................................6
4 Teeth with up to 7 cusps; 15-20 gill rakers on lower limb (ceratobranchial) of first gill arch; humeral spot roundish, contiguous
with the lateral stripe..................................................................................................................................A. brichardi
Teeth with up to 9 cusps; 13-17 gill rakers on lower limb (ceratobranchial) of first gill arch; humeral spot conspicuous well
separated from the posterior lateral stripe.......................................................................................................................5
5 10 circumpeduncular scales; body depth 2.3-2.5 in standard length.................................................................A. caudalis
12 circumpeduncular scales; body depth 2.9-3.8 in standard length............................................................A. conspectus
6 Humeral spot unconspicuous; a peduncular dark spot not extended onto the middle caudal rays......................A. smykalai
Humeral spot conspicuous, usually vertically elongate; no caudal spot............................................................................7
7 5½-6½ scales in tranverse row between lateral line and dorsal fin origin; body depth 2.6-3.4 times in standard length..........8
6½-7½ scales in tranverse row between lateral line and dorsal fin origin; body depth 2.4-3.0 times in standard length..........9
8 29-33 longitudinal line scales; 15-17 gill rakers on lower limb (ceratobranchial) of first gill arch......................A. nigropterus
32-35 longitudinal line scales; 12-14 gill rakers on lower limb (ceratobranchial) of first gill arch........................A. tumbensis
9 10 circumpeduncular scales; cuspids number [4/8 (upper jaw), 8 (lower jaw)].............................................A. compressus
13-15 circumpeduncular scales; cuspids number [5-7/7-11 (upper jaw), 6-11 (lower jaw)]...............................A. bifasciatus
Bibliography
Mbimbi Mayi Munene J.J. & Stiassny M.L.J., 2012. A new Alestopetersius (Characiformes: Alestidae) from the Kwilu River (Kasai basin) of central Africa; with a phylogeny for the genus and synonymy of Duboisialestes. Zootaxa, 3166: 59-68.
Alestopetersius bifasciatus (Poll, 1967)
Types and type localities
Duboisialestes bifasciatus Poll, 1967a: 135, 138-141, fig. 31. Type locality: “Bokuma”. Holotype: MRAC 96575. Paratypes: MRAC 96578-581, 104634 (1), 105067-071, 153743, 93663, 142960-963; ZMA 104771.
Synonyms
Hemigrammopetersius duboisi (non Poll, 1959) Daget & Stauch, 1963
Duboisialestes bifasciatus Poll, 1967
Hemigrammopetersius bifasciatus Géry, 1977
Alestopetersius bifasciatus Mbimbi Mayi Munene & Stiassny, 2012
Common names
Estonian: Juttsaba-möldersalmler
Description
Diagnosis: body depth 2.8-3.3 and head length 3.7-4 in SL. Dental formula: [4/8-10 (upper jaw), 8 (lower jaw)]. Cuspids number: [5-7/7-11 (upper jaw), 6-11 (lower jaw)] (see figure below). Dorsal fin: II,8. Anal fin: III,19-22. Dorsal and caudal fins with more or less extending rays. Gill rakers: 13-15. Scales: 34-36 + 1-2 (longitudinal line); 7½ (above lateral line)/3½ (below lateral line), 13-15 around caudal peduncle. Lateral line scales: 30-36 tubes.
Alestopetersius bifasciatus: mouth open in lingual view.
Maximum reported size: 69.5 mm SL.
Colour: a thin mid-lateral black band, sometimes slightly visible. On the contrary, fins are strongly black blotched : basal and posterior margin of caudal median rays and caudal lateral rays darkened. Dorsal fin with more intensely darkened rays in male.
Alestopetersius bifasciatus: morphometric and meristic data. Values in parentheses indicate number of specimens examined with that count.
Affinities: this species is related to Alestopetersius tumbensis. It exist good meristic differences between the two species, revealed by appropriate series of specimens (see table below). Cuspids number: upper external row (5-7 for A. tumbensis and 5-7 for A. bifasciatus), upper internal row (8-14 for A. tumbensis and 7-11 for A. bifasciatus) and in the lower row (8-12 for A. tumbensis and 6-11 for A. bifasciatus) shows the generic relationship between these two species.
Main morphological differences between A. bifasciatus and A. tumbensis.
Distribution
Lake Tumba and the Tshuapa with associated rivers in the middle Congo River basin in Democratic Republic of the Congo; possibly also in the middle Congo River basin in Republic of 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
Alestopetersius brichardi Poll, 1967
Type and type locality
Alestopetersius brichardi Poll, 1967a: 83, 89-93, fig. 17. Type locality: “Yangambi, Lac Yandja”. Holotype: MRAC 121105. Paratypes: MRAC 121106-112, 88310, 137415, 153739, 42892, 88311-317, 101407, 104632-633, 153740.
Synonyms
Petersius leopoldianus (non Boulenger, 1899)
Alestopetersius brichardi Poll, 1967a
Hemigrammopetersius (Alestopetersius) brichardi Géry, 1977
Phenacogrammus brichardi Poll, 1967
Common names
Estonian: Brichardi möldersalmler
Description
Diagnosis: body depth 3.25-4 and head length 3.6-3.95 in SL. Dental formula: [4/8-10 (upper jaw), 8-10 (lower jaw)]. Cuspids number: [5/3-7 (upper jaw), 4-7 (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 29-35 + 1-2 (longitudinal line); 5½-6½ (above lateral line)/ 3½ (below lateral line); 10-12 scales around caudal peduncle. Lateral line scales 28-35 tubes.
Maximum reported size: 96 mm SL.
Colour: a wide uniform black lateral band from posterior edge of the eye up to the caudal-fin origin and continuing along its median rays. Scales of the dorsal region also with parallel bands, more or less visible. A humeral black mark. Fins hyalin or greyish or blackish.
Alestopetersius brichardi: morphometric and meristic data. Values in parentheses indicate number of specimens examined with that count.
Affinities: A. brichardi species belongs to dwarf Alestidae group with prominent chin and without any pair of internal teeth at the lower jaw, with lateral line complete or generally a little shortened, with filamentous unpaired fins and sometimes paired fins too, with numerous enough scales that often exceed thirty or so in longitudinal line and more than 4.5 scales above the lateral line, in transversal line. Four upper external teeth (5-7 cuspids), 8-10 upper internal teeth (5-11 cuspids), 8-10 lower teeth (4-11 cuspids. It can be distinguished from this species by very different meristic features (see table in Alestopetersius introduction).
Distribution
Pool Malebo (Stanley Pool), the middle Congo River, the Ruki drainage and the Lomami 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
Alestopetersius caudalis (boulenger, 1899)
Types and type localities
Petersius caudalis Boulenger, 1899: 89-90, pl. XXXVII, fig. 3. Type locality: “Boma”. Syntypes: MRAC 849, 850, 851-852, 853-854.
Petersius brumpti Pellegrin, 1906: 368-269. Type locality: “Rivière Aba”. Holotype: MNHN 1903-0294.
Petersius xenurus Boulenger, 1920: 5, 17-18, fig. 7. Type locality: “Avakubi”. Syntypes: MRAC 7205-209, 8060, 8105.
Synonyms
Petersius caudalis Boulenger, 1899
Petersius brumpti Pellegrin, 1906
Petersius xenurus Boulenger, 1920
Hemigrammopetersius brumpti Myers, 1929
Hemigrammopetersius caudalis Myers, 1929
Hemigrammopetersius xenurus Myers, 1929
Micralestes grandi Fowler 1936
Alestopetersius caudalis Sterba, 1963
Alestopetersius hilgendorfi grandi Hoedeman, 1951
Alestopetersius (Nannopetersius) caudalis Hoedeman, 1951
Alestopetersius (Rhabdopetersius) leopoldianus brumpti Hoedeman, 1951
Alestopetersius (Petersialestes) xenurus xenurus Hoedeman, 1951
Phenacogrammus (Rhabdopetersius) leopoldianus brumpti Hoedeman, 1951
Phenacogrammus (Petersialestes) xenurus Hoedeman, 1956
Phenacogrammus (Nannopetersius) caudalis Hoedeman, 1956
Hemigrammopetersius (Alestopetersius) caudalis Géry, 1977
Common names
Danish: Gul congotetra
English: Yellow-tailed African characin/Yellow-tailed African tetra/Yellowtail tetra (USA)
Estonian: Kiilsaba-kongosalmler/Kiilsaba-möldersalmler
Finnish: Keltapyrstöalesti/Keltapyrstökongontetra
German: Gelber Kongosalmler
Polish: Swiecik zolty
Description
Diagnosis: body depth 2.5-2.8 (2.3-2.5) and head length 3.45-3.9 (3.5-4) in SL. Dental formula: [4/8-9 (upper jaw), 8-10 (lower jaw)] [type: 4/8 -8 (upper jaw)]. Cuspids number: [3-4/5-9 (upper jaw), 4-8 (lower jaw)]. Dorsal fin filamentous: II,8 (II,8). Anal fin: III,19-22 (III-IV,19-20). Caudal fin with extended median rays. Gill rakers: 13-17 (16-18). Scales 27-32 + 1-2 (29-30) (longitudinal line); 5½-6½ (above lateral line)/3½ (below lateral line) ] [type: 5½ (above lateral line)/3½ (below lateral line)]; 10 scales around caudal peduncle. Lateral line scales 26-31 tubes.
Maximum reported size: 74 mm SL.
Colour: a vertical black humeral mark more or less visible. A black lateral line widening at the back and extending intensely along median caudal-fin rays. Fins are hyalin or greyish.
Affinities: it can be distinguished from other Alestopetersius species by different meristic features (see table in Alestopetersius introduction).
Distribution
Lower and middle Congo River basin in Democratic Republic of the Congo and Central African Republic, including the marine lower Congo, Lake Tumba, Ruki drainage, Ubangi, Uele, Itimbiri, Aruwimi and Lindi-Tshopo (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: this is a commercially harvested aquarium species.
Bibliography
Alestopetersius compressus (Poll & Gosse, 1963)
Type and type locality
Petersius compressus Poll & Gosse, 1963: 47-48, 72, pl. In fig. 2. Type locality: “Rivière otolo”. Holotype: MRAC 137845. Paratypes: MRAC 102218-219, 137846-847, 137848-849, 13750-751, 137852-855.
Synonyms
Petersius compressus Poll & Gosse, 1963
Alestopetersius compressus Poll, 1967
Hemigrammopetersius (Alestopetersius) compressus Géry, 1977
Common names
Estonian: Koger-möldersalmler
Description
Diagnosis: body depth 2.4-3 (2.4) and head length 3.7-3.9 (3.8) in SL. Dental formula: [4/8 (upperjaw), 8 (lowerjaw] [type: 4/8 (upperjaw), 8 (lowerjaw)]. Cuspids number: [4/4-7 (upperjaw), 5-7 (lowerjaw)] (see figure below). Dorsal fin filamentous: II,8 (II,8). Anal fin: III,19-21 (III,20). Caudal fin with non-extended median rays. Gill rakers: 13-14 (15). Scales: 30-33 + 1-2 (30) (longitudinal line); 6½-7½ (above lateral line)/ 3½ (below lateral line) [type: 7½ (above lateral line)/ 3½ (below lateral line)]; 10 (10) scales around caudal peduncle. Lateral line scales 30-35 tubes.
Alestopetersius compressus: mouth open in lingual view.
Maximum reported size: 98 mm SL.
Colour: a vertical black humeral mark more or less visible. A black lateral line. Fins are hyalin or greyish.
Affinities: it can be distinguished from other Alestopetersius species by different meristic features (see table in Alestopetersius introduction).
Distribution
Middle Congo River basin, in the middle Congo River, Itimbiri, Aruwimi, Lindi-Tshopo, Lomami and Wagenia Falls, 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
Alestopetersius conspectus Mbimbi Mayi Munene & Stiassny, 2012
Type and type locality
Alestopetersius conspectus Mbimbi Mayi Munene & Stiassny, 2012: 64, fig. 4-6. Type locality: “Kwilu River at Carrefour, 05.19160°S, 18.94947°E, Banduundu Province, Democratic Republic of Congo”. Holotype: AMNH 253473. Paratypes: AMNH 253475, 253476, 253477; CUMV 96797; MRAC B1.19.5-6; ZSM 40759.
Common names
Estonian: Kirev möldersalmler
Description
Diagnosis: relatively gracile and shallow-bodied, body depth 26.4-34.5 % SL (mean 32.1), greatest depth at vertical through pelvic-fin insertion. Head length 20.4-29.7 (mean 27.5), eye large, bony orbit diameter 28.2-37.2 % HL (mean 34.9). Dorsal head profile straight from upper lip to nape, gently convex from that point to dorsal-fin origin. Dorsal body profile gently convex along dorsal-fin base to caudal- fin base, ventral body profile gently convex between isthmus and anal-fin base, caudal peduncle slightly longer than deep. Mouth terminal, lower jaw prominent and slightly prognathous. Premaxilla with two teeth in outer row, each bearing five cusps, positioned opposite interspaces between and alternating with, four inner row teeth, each bearing 6-8 cusps (see figure below). Outermost premaxillary tooth is markedly compressed and elongate with 7 or 8 small evenly sized cusps and a low median cusp. Dentary with four teeth in outer row, each bearing 6 or 7 cusps, outermost tooth smallest in jaw. No inner row teeth on dentary.
Alestopetersius conspectus: mouth open in lingual view.
Dorsal-fin rays, ii 8; anal-fin rays, iii 18-20 (mode 19). Origin of dorsal fin slightly in advance of vertical through pelvic-fin insertion. There is muted sexual dimorphism in fin shape; anal-fin margin convex in mature males, and concave in females and juveniles. The first 4 or 5 branched rays of dorsal fin of mature males somewhat elongated and filamentous. Body covered with small, regularly imbricate scales. Lateral line complete, with 31-34 pored scales to caudal flexion, 6½-7 scale rows between lateral line and dorsal-fin insertion, 2½ between lateral line and pelvic-fin insertion, 12 circumpeduncular scales. Twelve to 14 elongate gill rakers arrayed along lower limb of first arch. Total vertebral count 36 or 37 (mode 37).
Alestopetersius conspectus: morphometric and meristic data. Values in parentheses indicate number of specimens examined with that count. Left hand column provides comparative data for an anomalous individual collected together with A. conspectus at Kwilu, Mbuji (AMNH 252479).
Maximum reported size: 56.9 mm SL.
Colour: in alcohol, base body coloration pale creamy brown with darker basal crescents at contact zones of contiguous scales on dorsum. In males faint humeral stripe present above pectoral fin, but no trace of humeral stripe present in preserved females. In males a broad black band extends from behind opercle, thickening gradually to caudal peduncle base, then narrows and extends to posterior caudal-fin margin. Distinctive broad black band in each caudal-fin lobe flank central black band and are separated from it by white bands. Remaining fins dusky hyaline, leading edge of pectoral fin dark brown or black. In females coloration similar but mid-lateral band and caudal-fin bands somewhat muted.
In life all individuals are iridescent silver with greenish-copper reflections anterolaterally, becoming bluish on flanks and caudal peduncle. Mid-lateral band is obscured anteriorly on body but clearly marked on caudal peduncle. Markings on caudal fin as in preserved specimens but much of the white interspaces between black bands are bright orange.
Affinities: A. conspectus is distinguished from A. smykalai, A. leopoldianus, A. nigropterus and A. caudalis in the possession of 12 (vs 10) circumpeduncular scales. It is readily distinguished from A. brichardi, A. compressus, A. hilgendorfi and A. tumbensis in the possession of a caudal-fin pigmentation consisting of a median black band extending to the caudal-fin margin and flanked by dense black bands in both upper and lower fin lobes. Alestopetersius bifasciatus, which shares similar caudal fin pigmentation, is distinguished from A. conspectus by the absence of a broad mid-lateral band on the body, and in tooth morphology. It can be distinguished from other Alestopetersius species by different meristic features (see table in Alestopetersius introduction).
Habitat and ecology
Numerous specimens of Alestopetersius conspectus were collected at all sample sites along a 35 km stretch of the river. Most were collected using seine nets at depths of between 1-2 m. Water temperature in the shallows where most specimens were collected was between 21–22.5°C and pH ranged from 5.8-6.5. The Kwilu River at the sampling sites is between 15-40 meters wide and the banks are variously covered with dense, undisturbed riparian vegetation, heavily degraded urban areas, and cleared agricultural areas (Mbimbi & Stiassny, 2011). Female specimens contain numerous, maturing eggs in the ovaries and males have enlarged testes suggesting that reproductive activity was approaching at time of capture (February). Short guts (ca. 60% of SL when unraveled) and large stomachs with 6-8 fleshy pyloric caeca are suggestive of a carnivorous diet, and all specimens examined contained large numbers of insect head capsules and disarticulated body parts, most of terrestrial origin, with a preponderance of ants and small midges presumably taken at the water surface.
Distribution
Currently known from the Kwilu River in the vicinity of Kikwit. Collections in the main channel of the Middle Congo River, the Kasai main channel in the region of Bandundu, and Lulua River (a neighboring tributary Kasai) did not recover any individuals of A. conspectus despite intensive sampling, suggesting that the species may be a Kwilu endemic (see also Faunafri).
IUCN assessment
Not evaluated
Bibliography
Alestopetersius hilgendorfi (Boulenger, 1899)
Types and type localities
Petersius hilgendorfi Boulneger, 1899: 91-92, pl. XXXVII, fig. 5. Type locality: “Kutu (Lake Leopold II), Ibali”. Syntypes MRAC 829, 830-835, 836-840, 841-844.
Petersius modestus Boulnger, 1899: 91-92, pl. XXXVII, fig. 6. Type locality: “Lake Leopold II”. Holotype: MRAC 828.
Synonyms
Petersius hilgendorfi Boulenger, 1899
Petersius modestus Boulenger, 1899
Hemigrammopetersius hilgendorfi Myers, 1929
Hemigrammopetersius modestus Myers, 1929
Micralestes hilgendorfi Fowler, 1936
Micralestes modestus Hoedeman, 1951
Alestopetersius hilgendorfi hilgendorfi Hoedeman, 1951
Micralestes (Micralestes) modestus Hoedeman, 1959
Alestopetersius hilgendorfi Hoedeman, 1956
Hemigrammopetersius (Alestopetersius) hilgendorfi Géry, 1977
Common names
Estonian: Hilgendorfi möldersalmler
Description
Diagnosis: body depth 2.65-3.50 (2.75) and head length 3.4-3.8 (4) in SL. Dental formula: [4/8-9 (upperjaw), 8-10 (lowerjaw)], [type: 4/8 (upperjaw), 8 (lowerjaw)]. Cuspids number [4-5/4-7 (upperjaw), 4-8 (lowerjaw)]. Dorsal fin filamentous: II,8 (II,8). Anal fin: III,19-23 (III,20 23). Caudal fin with extended rays or not. Gill rakers: 13-16 (15-16). Scales: 34-42 + 1-2 (35-36) (longitudinal line); 7½-8½ (above lateral line)/3½ (below lateral line), [type: 7½ (above lateral line) /3½ (lbelow lateral line)]; 13-15 scales around caudal peduncle. Lateral line scales : 33-42 tubes.
Maximum reported size: 108 mm SL.
Colour: a black humeral mark mainly in mature male. A black lateral line, sometimes a lateral black band at the back which may extend along caudal fin median rays which, on the other hand, may only be darkened. Unpaired fins hyalin or greyish.
Affinities: it can be distinguished from other Alestopetersius species by different meristic features (see table in Alestopetersius introduction).
Distribution
Pool Malebo and central Congo River basin in Democratic Republic of the Congo and Republic of Congo, including the middle Congo River, Lukenie, lakes Mai Ndombe and Tumba, Ruki drainage, Likouala-aux-Herbes and lower Lomami (see also Faunafri).
Assessed as Least Concern due to its large distribution, over a relatively pristine area, where there are no known major widespread threats.
Major threats: there are no threats known to be currently affecting this species.
Bibliography
Alestopetersius leopoldianus (Boulenger, 1899)
Type and type locality
Petersius leopoldianus Boulenger, 1899: 90-91, pl. XXXVII, fig. 4. Type locality: “Kutu (Lake Leopold II)”. Syntypes MRAC 818, 819, 820, 821-824, 825-827.
Synonyms
Petersius leopoldianus Boulenger, 1899
Hemigrammopetersius leopoldianus Myers, 1929
Alestopetersius (Rhabdopetersius) leopoldianus leopoldianus Hoedemen, 1951
Phenacogrammus (Rhabdopetersius) leopoldianus Hoedemen, 1956
Alestopetersius leopoldianus Poll, 1967
Hemigrammopetersius (Alestopetersius) leopoldianus Géry, 1977
Common names
Estonian: Leopoldi möldersalmler
Description
Diagnosis: body depth 3.35-3.75 (3.5-3.65) and head length 3.35-3.6 (3.5-3.65) in SL. Dental formula: [4/8-9 (upperjaw), 8-10 (lowerjaw)], [type: 4/8 (upperjaw), 8 (lowerjaw)]. Cuspids number: [3/3-6 (upperjaw), 5-7 (lowerjaw)]. Dorsal fin: II,8 (II,8), Anal fin: III,19-21 (III,19-20). Dorsal and caudal fins with non-extended rays in known specimens. Gill rakers: 24-29 (25-30). Scales: 28-30+1-2 (30-31) (longitudinal line); 5½(above lateral line)/3½(below lateral line) (5½/3½); 10 scales around caudal peduncle. Lateral line scales 29-31 tubes.
Alestopetersius leopoldianus: morphometric and meristic data. Values in parentheses indicate number of specimens examined with that count.
Maximum reported size: 92.5 mm SL.
Colour: a wide and uniform lateral black band from posterior edge of the eye to the base of the caudal fin and continuing along the median rays. Fins are greyish, dorsal fin as pectoral and pelvic rays are black.
Affinities: it can be distinguished from other Alestopetersius species by different meristic features (see table in Alestopetersius introduction).
Distribution
Lake Mai Ndombe middle Congo River, lower Lomami and Wagenia Falls in the middle Congo River basin in Democratic Republic of the Congo (see also Faunafri).
Although there are threats known in the area, the species is listed Least Concern because of its relatively wide distribution.
Major threats: in Lake Mai-N'Dombe, the use of small mesh size nets, mosquito nets are used as fishing nets. These nets are called caterpillar nets because they hold every species that is in the lake. Methane reservoirs discovered under the lake are expected to be exploited. In Lake Tumba, the mean mesh size of the nets used in this lake are around 1 cm, possibly causing threats. All bigger fish in Lake Tumba seem to be disappeared. The region north of the Congo River in the Kisangani area is threatened by gold mining.
Bibliography
Alestopetersius nigropterus Poll, 1967
Type and type locality
Alestopetersius nigropterus Poll, 1967: 84, 93-97, fig. 18. Type locality: “Ibali”. Holotype: MRAC 845. Paratypes: MRAC 820, 842-844.
Synonyms
Petersius hilgendorfi (non Boulenger, 1899) Boulenger, 1899
Petersius leopoldianus (non Boulenger, 1899) Boulenger, 1899
Alestopetersius nigropterus Poll, 1967
Hemigrammopetersius (Alestopetersius) nigropterus Géry, 1977
Common names
Estonian: Mustuim-möldersalmler
Description
Diagnosis: body depth 2.9-3.4 and head length 3.55-3.75 in SL. Dental formula: [4/8 (upper jaw), 8 (lower jaw)]. Cuspids number: [6/6-9 (upper jaw), 6-9 (lower jaw)]. Dorsal fin filamentous: II,8. Anal fin: III,19-22. Caudal fin non-filamentous in known specimens. Gill rakers: 15-17. Scales: 28-31 + 1-2 (longitudinal line);. 5½-6½ (above lateral line)/3½ (below lateral line); 10 scales around caudal peduncle. Lateral line scales 28-31 tubes.
Alestopetersius nigropterus: morphometric and meristic data. Values in parentheses indicate number of specimens examined with that count.
Maximum reported size: 77 mm SL.
Colour: a black lateral line more visible at the back. A vertical black humeral mark. Unpaired fins are black. A bright transversal area with some contrast at the caudal-fin base.
Affinities: it can be distinguished from other Alestopetersius species by different meristic features (see table in Alestopetersius introduction).
Distribution
Lake Mai-Ndombe (middle Congo River basin) in Democratic Republic of the Congo (see also Faunafri).
The species is only known from Lake Mai-N'dombe (Leopold II), which has a surface of 2,300 km². The use of small mesh size nets (mosquito nets) poses a threat to the population size. The species is therefore listed as Endangered.
Major threats: in Lake Mai-N'Dombe, the use of small mesh size nets, mosquito nets are used as fishing nets. These nets are called caterpillar nets because they hold every species that is in the lake. Methane reservoirs discovered under the lake are expected to be exploited.
Bibliography
Alestopetersius smykalai Poll, 1967
Type and type locality
Alestopetersius smykalai Poll, 1967: 84, 97-99, fig. 19. Type locality: “Aba, Bas Niger, Nigeria”. Holotype MRAC 153776, paratype MRAC 153777.
Synonyms
Alestopetersius smykalai Poll, 1967
Hemigrammopetersius (Alestopetersius) smykalai Géry, 1977
Rhabdalestes smykalai Paugy, 1990
Common names
Estonian: Teemant-möldersalmler
Finnish: Timanttialesti
German: Blauer Diamantsalmer
Description
Diagnosis: body depth 3-3.16 and head length 3.7-3.9 in SL. Dental formula: [4/8 (upper jaw), 9-10 (lower jaw)]. Cuspids number: [5/6-7 (upper jaw), 3-7 (lower jaw)]. Dorsal fin filamentous: II,8. Anal fin: III,18-19. Caudal fin non-filamentous in known specimens. Gill rakers: 16. Scales 27 +2 (longitudinal line); 5½-6½ (above lateral line)/3½ (below lateral line); 10 scales around the caudal peduncle. Lateral line scales 25-26 tubes.
Alestopetersius smykalai: mouth open in lingual view.
Maximum reported size: 60 mm SL.
Colour: overall colouring is silvery. A thin posterior mid-lateral black line ending in an horizontal oblong mark along caudal peduncle, not continuing along median rays of the caudal fin. Fins are hyalin or scarcely darkened, notably outer margin.
Affinities: this species is rather similar to A. caudalis Boulenger of River Congo bassin, including Lower River Congo, but it can be distinguished by a more elongated body, the absence of filamentous extensions to the caudal median rays and a different colour pattern though comparable. It can be distinguished from other Alestopetersius species by different meristic features (see table in Alestopetersius introduction).
Distribution
Lower Niger Delta, Nigeria (see also Faunafri).
Assessed as Vulnerable due to an inferred decline of greater than 30% over the past fifteen years. This is due to habitat degradation, water pollution and introduced species within the lower Niger River basin.
Major threats: A. smykalai is threatened by habitat degradation. The Niger Delta has suffered extensive environmental pollution and the crisis is still on going. The Niger Delta is endowed with immense natural resources, particularly crude oil, and in addition, Nigeria has the largest natural gas reserves in Africa. As a consequence, environmental problems arise from oil and gas-related development activities, oils spills, refinery operations, oil transportation, gas flaring, dredging of canals and land taken for the construction of facilities. Areas near such outfalls are subjected to chronic pollution, which is of significance for fish resources and fisheries (Laë et al., 2004). Construction of dams along the Niger River during the last 25 years has significantly disrupted the hydrological balance of the lower Niger River (Bustamante 2003). Population pressure and agricultural land degradation also exacerbate biodiversity losses in the region as they induce people to expand agricultural production and increase fishing pressure (Bustamante, 2003).
In addition to habitat degradation, it is possible that A. smykalai is negatively affected by introduced species. In Nigeria, nine species were introduced since the 1970s, mainly for aquaculture. The ecological effects of these introduced species are unknown (Laë et al., 2004).
Bibliography
Alestopetersius tumbensis Hoedeman, 1951
Type and type locality
Alestopetersius (Petersialestes) xenurus tumbensis Hoedeman, 1951: 8. Type locality: “Lac Tumba”. Holotype ZMA 100166, paratype ZMA 100166A.
Synonyms
Alestopetersius (Petersialestes) xenurus tumbensis Hoedeman, 1951
Phenacogrammus (Petersialestes) xenurus tumbensis Hoedeman, 1959
Hemigrammopetersius duboisi Poll, 1959
Duboisialestes tumbensis Poll, 1967
Hemigrammopetersius tumbensis Géry, 1977
Alestopetersius tumbensis Mbimbi Mayi Munene & Stiassny, 2012
Common names
Estonian: Tumba möldersalmler
Description
Diagnosis: body depth 2.6-3 and head length 3.55-3.8 in SL. Dental formula: [4/8 (upper jaw), 8 (lower jaw)]. Cuspids number: [5-7/8-14 (upper jaw), 8-12 (lower jaw)] (see figure below). Dorsal fin: II,8. Anal fin: III,20-22. Dorsal and caudal fins with more or less extending rays. Gill rakers on the lower limb of the first gill arch: 12-14. Scales: 30-33 + 2 (longitudinal line); 5½-6½ (above lateral line)/3½ (below lateral line); 10-12 around caudal peduncle. Lateral line scales: 23-30 tubes.
Alestopetersius tumbensis: mouth open in lingual view.
Alestopetersius tumbensis: morphometric and meristic data.
Maximum reported size: 68 mm SL.
Colour: a thin mid-lateral black band widening at the back and extending along the caudal fin median rays, particularly in mature male. A vertical black humeral blotch. Fins are greyish.
Affinities: it can be distinguished from other Alestopetersius species by different meristic features (see table in Alestopetersius introduction).
Distribution
Pool Malebo, Kwenge River (Kwilu River drainage) and Lake Tumba in Democratic Republic of the Congo. Also reported from the Kouyou River (tributary of the Likouala River, middle Congo River basin) in Republic of Congo (see also Faunafri).
Although there are threats to the species known, it is relatively widespread, and is thus listed as Least Concern.
Major threats: urbanisation at Pool Malebo (Stanley Pool) forms a problem in the region through sewage cast and lead toxicity, mainly coming from car oil and a lot of boat traffic. In Lake Tumba, the mean mesh size of the nets used in this lake are around 1 cm, possibly causing threats. All bigger fish in Lake Tumba seem to be disappeared. Lake Tumba does not produce fish any more. All the fishermen turned to agriculture themselves.
Bibliography
