Brachypetersius
Brachypetersius Hoedeman, 1956
Brachypetersius is distinguished from all other Petersiini by the combination of the following characters: two outer-row premaxillary teeth (four teeth total across both upper jaw elements), inner dentary teeth present, lateral line complete, 4½ -5½ scales in transverse row between lateral line and dorsal-fin origin. Body form tends to be very robust. The genus, along with Nannopetersius, is questionably distinct from Phenacogrammus; the three genera are distinguished (sensu Poll, 1967) on the basis of a combination of features that display intra- and interspecific variation and involve continuous variables showing broad overlap between species. For example, Brachypetersius and Phenacogrammus are nearly indistinguishable apart from the condition of the extent of the lateral line and a tendancy toward a deeper body in the former genus. Nannopetersius and Brachypetersius share the complete lateral line and relatively deep body, but are distinguished on the basis of greater number (6½ vs 4½-5½, respectively) of transverse scales between the lateral line and dorsal fin origin. Géry (1977 and 1995) regards the degree of difference among these species assemblages as insufficient support for generic level discrimination and consequently groups all under Phenacogrammus. To date, however, no published studies have proposed characters drawn from in-depth, comprehensive morphological survey as diagnostic for alestid genera and, consequently, there is no evidentiary basis for reaching an objective determination on this issue. For the moment, pending the outcome of future revisionary and phylogenetic work, it seems most reasonable to retain generic-level status for these taxa for purposes of discussion and comparison to previous classifications.
Synonyms
Micralestes Boulenger, 1899 (partim)
Petersius Boulenger, 1899 (partim)
Hemigrammopetersius Pellegrin, 1929 (partim)
Bathyaethiops Fowler, 1949(partim)
Alestopetersius (Brachypetersius) Hoedeman, 1951 (partim)
Phenacogrammus (Brachypetersius) Hoedeman, 1956 (partim)
Type species Brachypetersius altus
Micralestes altus Boulenger, 1899 by original designation of Hoedeman, 1956.
Currently, six species are assigned to the genus Brachypetersius.
Key to species.
1 5½ scales in transverse row between lateral line and dorsal origin..........................................................................2
4½ scales in transverse row between lateral line and dorsal origin..........................................................................3
2 16-17 anal fin branched rays; 29 scales along lateral line....................................................................B. notospilus
19-22 anal fin branched rays; 29 scales along lateral line..........................................................................B. huloti
3 18-19 anal fin branched rays; 27-28 scales along lateral line..............................................................B. gabonensis
At least 20 anal fin branched rays; 23-27 scales along lateral line..........................................................................4
4 21-23 anal fin branched rays; 25-30 scales along lateral line.............................................................B. cadwaladeri
20-27 anal fin branched rays; 20-24 scales along lateral line..................................................................................5
5 A large black elongated spot on all the lower part of the caudal peduncle...................................B. pseudonummifer
A large black rounded spot on the lower part of the caudal peduncle............................................................B. altus
Some metric and meristic characteristics of Brachypetersius species are given below.
Main morphological differences between the six Brachypetersius species.
Brachypetersius altus (Boulenger, 1899)
Types and type localities
Micralestes altus Boulenger, 1899: 88, pl. XXXVI, fig. 5. Type locality: “Bikoro, lac Tumba”. Syntypes: MRAC 806, 807-810, 811-815, 1281.
Petersius nummifer Boulenger, 1920: 5, 18. Type locality: “Poko”. Syntypes; MRAC 8057-8058.
Micralestes rochefoucauldi Fowler, 1936: 256-257, fig. 23. Type locality: “Fort-Sibut, Ubanghi-Shari”. Holotype: ANSP 65549. Paratypes: ANSP 65550-65551.
Synonyms
Micralestes altus Boulenger, 1899
Petersius nummifer Boulenger, 1920
Hemigrammalestes altus Holly, 1930
Micralestes nummifer Trewavas, 1936
Micralestes rochefoucauldi Fowler, 1936
Alestopetersius (Alestogrammus) nummifer Hoedeman, 1951
Alestopetersius (Brachypetersius) altus Hoedeman, 1951
Alestopetersius (Brachypetersius) rochefoucauldi Hoedeman, 1951
Phenacogrammus (Alestogrammus) nummifer Hoedeman, 1959
Phenacogrammus (Brachypetersius) rochefoucauldi Hoedeman, 1959
Phenacogrammus (Brachypetersius) altus Hoedeman, 1959
Bathyaethiops rochefoucauldi Poll, 1959
Bathyaethiops nummifer Poll, 1959
Bathyaethiops altus Poll, 1959
Common names
Estonian: Kõrge rõkstetra
Finnish: Punakongontetra
Description
Diagnosis: body depth 2.1-3.1 (2.2-2.35) and head length 3.2-3.55 (3.5-3.65) in SL. Dental formula: [4/8 (upper jaw), 8-10/2 (lower jaw)], [types: 4/8-10 (upper jaw), 8-10/2 (lower jaw)]. Cuspids number: [3-5/4-7 (upper jaw), 3-6/1]. Dorsal fin: II,8 (II,8). Anal fin: III, 22-27 (III,23-25). Fins are never filamentous. Gill rakers: 10-13 (12). Scales: 21-25 + 1-2 (23-26) (longitudinal line); 4½ (above laterla line)/3½ (below lateral line), (4½/3½); 10 around caudal peduncle. Lalteral line scales: 21-26 tubes.
Brachypetersius altus: morphometric and meristic data.
Maximum reported size: 99 mm SL.
Colour: a large black peduncular spot on lower part and in front of the caudal peduncle. Humeral mark slightly visible or not. Scales of the flanks are darkened to their base in adults.
Affinities: it can be distinguished from other Brachypetersius species by different meristic features (see figure in Breachypetersius introduction).
Remark: except the form of the anal fin, there is no sexual dimorphism between sexes (see figure above).
Distribution
Middle Congo River basin in Cameroon, Central African Republic, Republic of Congo and 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
Brachypetersius cadwaladeri (Fowler, 1930)
Types and type locality
Petersius cadwaladeri Fowler, 1930: 30-31, fig. 3. Type locality: “Lulua River, Belgian Congo”. Holotyê: ANSP 51748.
Micralestes massarti Poll, 1945: 52-54, fig. 7. Type locality: “Mukishi, affluent Lomami”. Syntypes: MRAC 30804-30805.
Synonyms
Petersius cadwaladeri Fowler, 1930
Micralestes massarti Poll, 1945
Hemigrammopetersius cadwaladeri Poll, 1945
Bathyaethiops massarti Poll, 1959
Brachypetersius cadwaladeri Poll, 1967
Phenacogrammus (Brachypetersius) cadwaladeri Géry, 1977
Common names
Estonian: Kongo rõkstetra
Description
Diagnosis: body depth 2.4-3.1 (3.1-3.65) and head length 3.5-3.95 (3.4-3.65) in SL. Dental formula: [4/8 (upper jaw), 8/2 (lower jaw)], [type: 4/8 (upper jaw), 8 (lower jaw)] (see figure below). Cuspids number: [5/4-7 (upper jaw), 5-7/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,21-23 (III,21-23). Gill rakers: 11-14 (12). Scales: 25-30+1-2 (28-31+2-3) (longitudinal line); 4½ (above lateral line)/3½ (below lateral line); 10 around caudal peduncle. Lateral line scales: 22-28 (28-31) tubes.
Brachypetersius cadwaladeri: mouth open in lingual view.
Maximum reported size: 69 mm SL.
Colour: a large oval pedunculary black blotch on lower part and in front of the caudal peduncle origin, extending more or less backwards up to the caudal fin origin. There is a humeral mark. Scales of the flanks are more or less darkened to their base.
Remark: specimens from Kitutu, Lambo and Kigongo are a bit smaller and have less longitudinal line scales.
Affinities: it can be distinguished from other Brachypetersius species by different meristic features (see figure in Brachypetersius introduction).
Distribution
Upper Lulua (Kasai drainage, middle Congo River basin), upper Lomami (middle Congo River basin) and right bank tributaries of the Lualaba River (upper Congo River basin), including the Elila and Luama, in Democratic Republic of the Congo. Reported from Lake Tanganyika, but this presence seems dubious (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
Brachypetersius gabonensis Poll, 1967
Type and type locality
Brachypetersius gabonensis Poll, 1967: 104-105, 108-110, fig. 22. Type locality: “Diala, route Lambaréné-Mouila”. Holotype: MRAC 153770. Paratypes: MRAC 153771-153772, 153773-153775.
Synonyms
Brachypetersius gabonensis Poll, 1967
Phenacogrammus (Brachypetersius) gabonensis Géry, 1977
Common names
Estonian: Gaboni rõkstetra
Description
Diagnosis: body depth 2.8-3.25 and head length 3.5-3.75 in SL. Dental formula: 4/8 (upper jaw), 8/2 (lower jaw). Cuspids number: [3-4/4-7 (upper jaw), 3-6 (upper jaw), 1 (lower jaw) (see figure below). Dorsal and caudal fins non-filamentous. Dorsal fin: II,8. Anal fin: III,18-19. Gill rakers: 10-12. Scales 27-28+1-2 (longitudinal line), 4½ (above lateral line)/3½ (below lateral line); 10-11 around caudal peduncle. Lateral line scales: 25-27 tubes.
Brachypetersius gabonensis: mouth open in lingual view.
Brachypetersius gabonensis: morphometric and meristic data.
Maximum reported size: 70 mm SL.
Colour: a mid-lateral blackish band not well visible accentuating a very clear black line at the back, marked with a more or less clear oval humeral blotch above the pectoral fins. Fins are greyish.
Affinities: most similar to Brachypetersius huloti from the Congo River basin, from which it differs in the extension of the lateral band onto the median caudal fin rays, presence of a humeral spot and fewer scales (4½-5½ vs 6½) in transverse series between lateral line and dorsal fin origin. It can be distinguished from other Brachypetersius species by different meristic features (see figure in Brachypetersius introduction).
Distribution
Lower Guinea endemic, restricted to the Ogowe and Como River basins in Gabon (see also Faunafri).
The species is widespread within the Central Africa assessment region and is assessed as Least Concern.
Major threats: there is no information available on threats to this species.
Bibliography
Brachypetersius huloti (Poll, 1954)
Type and type locality
Micralestes huloti Poll, 1954: 58-59, fig. 2. Type locality: “Yangambi, rivière Lomboma”. Holotype: MRAC 68616. Paratypes: MRAC 120878-120883, 120884-120925, 120929-120938, 120939-120960, 120961-120965, 120966-120967, 120968-120971, 120972-120980, 120981-120982, 120983, 120984-120986, 120987-120989, 120990-120991, 120992, 120993, 120994-120995, 120996-121000, 121001-121010, ISNN 250-268.
Synonyms
Micralestes huloti Poll, 1954
Brachypetersius huloti Poll, 1967
Phenacogrammus (Brachypetersius) huloti Géry, 1977
Common names
Estonian: Rohekas rõkstetra
Finnish: Viherkongontetra
German: Hulots Kongosalmler
Description
Diagnosis: body depth 2.5-3 (2.3-2.75) and head length 3.4-3.8 (3.25-3.65) in SL. Dental formula: [4/8 (upper jaw), 8/2 (lower jaw)], [type: 4/8 (upper jaw), 8/2 (lower jaw)] (see figure below). Cuspids number: [3-5/4-7 (upper jaw), 3-5/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,19-22 (II,19-22). Dorsal and caudal fins non-filamentous. Gill rakers: 9-11 (10). Scales 23-27+1-2 (24-26) (longitudinal line); 5½ (above lateral line)/3½ (below lateral line), (5½/3½), 10 (10) scales around caudal peduncle. Lateral line scales 22-27 tubes.
Brachypetersius huloti: mouth open in lingual view.
Maximum reported size: 95 mm SL.
Colour: a wide mid-lateral black band, from the head to the caudal-fin origin, larger and darker in male than in female. Fins are hyalin except dorsal and caudal ones which are greyish, especially in male.
Affinities: it can be distinguished from other Brachypetersius species by different meristic features (see figure in Brachypetersius introduction).
Distribution
Fulakari River headwaters (lower Congo River basin) in Republic of Congo and the middle Congo River basin, including the middle Congo River, Lukenie, Lomami and a non-verified record from the Ruki drainage in Democratic Republic of the Congo. Reported from the upper Niari, but this presence seems dubious (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
Brachypetersius notospilus (Pellegrin, 1930)
Type and type locality
Micralestes notospilus Pellegrin, 1930: 197-198. Type locality: “La Passa, Haut Ogôoué”. Syntypes: MNHN 1929-0234.
Synonyms
Micralestes notospilus Pellegrin, 1930
Brachypetersius notospilus Poll, 1967
Phenacogrammus (Brachypetersius) notospilus Géry, 1977
Common names
Estonian: Sabalaik-rõkstetra
Description
Diagnosis: body depth 2.6-2.9 (2.75-3) and head length 3.55-3.75 (3.5-3.75) in SL. Dental formula: [4/8 (upper jaw), 10/2 (lower jaw)], [type: 4/8 (upper jaw), 10/2 (lower jaw)]. Cuspids number: [3-4/4-7 (upper jaw), 3-5/1 (lower jaw)]. Dorsal fin: II,8 (II,8). Anal fin: III,16-17 (III,16-18). Gill rakers: 9-10 (9-11). Scales 29 + 2 (24-26) (longitudinal line); 5½ (above lateral line)/3½ (below leteral line), (4½/3½). Lateral line scales : 28-30 tubes.
Maximum reported size: 81 mm SL.
Colour: a black peduncular blotch not well limited on the lower part of the caudal peduncle (a paratype specimen without any visible mark was observed).
Affinities: it can be distinguished from other Brachypetersius species by different meristic features (see figure in Brachypetersius introduction).
Distribution
Lower Guinea endemic, known from the Kouilou River basin in the Republic of Congo and the Ogowe River basin in Gabon (see also Faunafri).
Brachypetersius notospilus is only from the type locality in the Upper Ogowe and known from the Kouilou River. This is a very poorly sampled/surveyed areas and 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: the species is threatened by intensive commercial logging leading to sedimentation.
Bibliography
Brachypetersius pseudonummifer Poll, 1967
Type and type locality
Brachypetersius pseudonummifer Poll, 1967: 105-106, 110-115, fig. 23. Type locality: “Avakubi”. Holotype: MRAC 2919. Paratypes: MNHN 1967-0665, MRAC 2949, 2968-2972, 2992-3000, 7840-7841, 7992-7993, 8071, 14522, 14525-14527, 14529, 14533-14534, 15502-15503.
Synonyms
Micralestes altus (partim) Nichols & Griscom, 1917
Petersius nummifer (partim) Poll, 1945
Brachypetersius pseudonummifer Poll, 1967
Common names
Estonian: Viirgsaba-rõkstetra
Finnish: Peräjuovatetra
Description
Diagnosis: body depth 2.1-2.5 and head length 3.6-3.95 in SL. Dental formula: [4/8 (upper jaw), 8-10/2 (lower jaw)] (see figure below). Cuspids number: [3-5/5-8 (upper jaw), 3-6/1 (lower jaw). Dorsal fin: II,8. Anal fin: III,20-24. Gill rakers: 11-12. Scales 20-22+1-2 (longitudinal line); 4½ (above lateral line)/3½ (below lateral line); 10 around caudal peduncle. Lateral line scales 18-22 tubes.
Brachypetersius pseudonummifer: mouth open in lingual view.
Brachypetersius pseudonummifer: morphometric and meristic data.
Maximum reported size: 89 mm SL.
Colour: a large pedunculary black blotch extending along all the lower part of the caudal peduncle, sometimes up to the caudal-fin origin. A humeral mark or not. Scales of the flanks darkened to their base in adult.
Affinities: it can be distinguished from other Brachypetersius species by different meristic features (see figure in Brachypetersius introduction).
Distribution
Middle Congo River, 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 threats: none known.
Bibliography
