Nannopetersius
Nannopetersius is distinguished from all other Petersiini by the combination of the following characters:
Body form tends to be very robust and males tend to have elongate, filamentous dorsal and anal fins. The genus, along with Brachypetersius, is questionably distinct from Phenacogrammus. 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 above the lateral line.
Synonyms
Petersius Boulenger, 1899 (partim)
Micralestes Boulenger, 1899 (partim)
Alestopetersius (Nannopetersius) Hoedeman, 1951 (partim)
Phenacogrammus (Nannopetersius) Hoedeman, 1956 (partim)
Nannopetersius appeared as a subgenus of Phenacogrammus
Type species Nannopetersius ansorgii
Patersius ansorgii Boulenger, 1910 by original designation of Hoedeman, 1956.
Currently, three species are assigned to the genus Nannopetersius.
Key to species.
1 14-17 gill rakers on lower limb (ceratobranchial) of first gill arch; flanks with dark lateral band, more or less restricted to the
posterior thrird of the trunk and caudal fin base extending onto the median caudal fin rays; caudal fin lobes unpigmented
................................................................................................................................................................N. ansorgii
10-12 gill rakers on lower limb (ceratobranchial) of first gill arch; flanks with dark lateral band, continuous from opercle
through caudal fin base and extending onto the median caudal fin rays; caudal fin lobes with pigment stripe more or less
vertically across the posterior third of fin.....................................................................................................................2
2 28-30 scales along lateral line; caudal peduncle longer than deep (1.36-1.52); snout length 0.27-0.29 in head length..........
..........................................................................................................................................................N. mutambuei
30-35 scales along lateral line; caudal peduncle nearly as long as deep (0.97-1.21); snout length 0.18-0.23 in head length..
...............................................................................................................................................................N. lamberti
Nannopetersius ansorgii (Boulenger, 1910)
Types and type localities
Petersius ansorgii Boulenger, 1910: 543. Type locality: “Lake Kulungu, Bengo River (Angola)”. Syntypes: BMNH 1910.11.28:71, 1910.11.28:72-80, 1910.11.28:81-85.
Petersius ubalo Boulenger, 1910: 544. Type locality: “Lake Kumango, Bengo River”. Syntypes: BMNH 1910.11.28:87, 1910.11.28:88-92, 1910.11.28:93-100.
Synonyms
Petersius ansorgii Boulenger, 1910
Petersius ubalo Boulenger, 1910
Petersius ansorgei Pellegrin, 1924
Micralestes ansorgii Myers, 1929
Micralestes ubalo Myers, 1929
Alestopetersius (Nannopetersius) ansorgei ansorgei Hoedeman, 1951
Alestopetersius (Nannopetersius) ansorgei ubalo Hoedeman, 1951
Phenacogrammus (Nannopetersius) ansorgei Hoedeman, 1956
Phenacogrammus (Nannopetersius) ansorgei ubalo Hoedeman, 1956
Nannopetersius ansorgii Poll, 1967
Common names
Estonian: Ansorge`i pikkuimsalmler
Finnish: Sinikongontetra
German: Ansorges Blauer Kongosalmler
Description
Diagnosis: body depth 2.5-3.4 (2.5-2.75) and head length 3.35-4 (3.5-4) in SL. Dental formula: [4/8-9 (upper jaw), 8/2 (lower jaw)], [type: 4/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3-5/4-7 (upper jaw), 3-7/1 (lower jaw)]. Dorsal fin filamentous or not: II,8 (II,8). Anal fin: II-IV,19-22 (II-III,20-23). Caudal fin non-filamentous. Gill rakers: 14-17 (18-20). Scales: 29-34+1-2 (31-33) (longitudinal line); 6½-7½ (6½-7½) (above lateral line)/3½ (3½) (below lateral line); 10 around caudal peduncle. Lateral line scales: 27-34 tubes (see table below).
Nannopetersius ansorgii: morphometric and meristic data.
Maximum reported size: 91 mm SL.
Colour: a mid-lateral black band not really distinct ahead, wider and more visible at the back on the caudal peduncle, extending along median rays of the caudal fin. There is a vertical black humeral mark above the pectoral fins. Fins are greyish with a black margin. In female, there is only a black diamond-shaped blotch, shorter on caudal peduncle and median caudal rays.
Affinities: see N. mutambuei.
Distribution
This species is native to Gabon, Democratic Republic of the Congo, Guinea Equatorial, and Angola. The record from Matadi from the Lower Congo and the type locality in Angola are doubtful though.
Central Africa: It is known from the Benito, Chiloango, Kouilou, Loeme and Ogowe Rivers and from Equatorial Guinea. Elsewhere, it is known from the Bengo and Congo from Congo to Angola.
Southern Africa: In Angola, the species occurs in Bengo River (Lake Kilunda, Lake Rumango), Chiloango River (Loango, Lukula and Luali Rivers, and Lake Chiloango) systems (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 southern Africa.
Major threats: there is no information available on threats to this species.
Bibliography
Nannopetersius lamberti Poll, 1967
Type and type locality
Nannopetersius lamberti Poll, 1967: 118, 122-125, fig. 26. Type locality: “Ponite Noire, Sounda”. Holotype: MRAC 153760. Paratypes: MRAC 153761-153769.
Synonyms
Nannopetersius lamberti Poll, 1967
Phenacogrammus (Nannopetersius) lamberti Géry, 1977
Common names
Estonian: Lamberti tukktetra
Description
Diagnosis: body depth 2.5-3.3 and head length 3.6-3.85 in SL. Dental formula: [4/8 (upper jaw), 8/2 (lower jaw)]. Cuspids number: [3-5/4-7 (upper jaw), 3-5/1 (lower jaw)]. Dorsal fin filamentous or not: II,8. Anal fin: III,20-22. Caudal fin non-filamentous. Gill rakers: 10-12. Scales 28-32+1-2 (longitudinal line); 6½-7½ (above lateral line)/3½ (below lateral line); 10 around caudal peduncle. Lateral line scales: 28-33 tubes (see table below).
Nannopetersius lamberti: morphometric and meristic data.
Maximum reported size: 73.5 mm SL.
Colour: a mid-lateral black band from the eye to the caudal fin, where it extends along median rays. A black bar or an oblique blotch goes through the caudal-fin lobes. Dorsal and caudal fins are darkened at the end of the rays.
Affinities: see N. mutambuei.
Distribution
Present in Ntem, Ogowe, Nyanga and Kouilou River basins. Also reported from the lower Congo (see also Faunafri).
The species is widespread without major threats throughout central Africa and is assessed as Least Concern.
Major threats: none known.
Bibliography
Nannopetersius mutambuei Wamuini Lunkayilakio & Vreven, 2008
Type and type locality
Nannopetersius mutambuei Wamuini Lunkayilakio & Vreven, 2008: 369-372, fig. 2-6. Type locality: “Democratic Republic of Congo: Lower Congo; Ngufu River, tributary of Inkisi River, at bridge Luangu village, Kavuaya village, 5°04’44.2”S 15°07’51.0”E”. Holotype: MRAC A6.007.P.0222. Paratypes: MRAC A6.007.P.0223-0225, A6.007.P.0227-0229, A6.007.P.0231, A6.007.P.0232-0233, AMNH 239655 (formerly MRAC A6.007.P.0226, A6.007.P.0230).
Common names
Estonian: Inkisi tukktetra
Description
Diagnosis: body depth 2.7-3.1 and head length 3.8-4.2 in SL. Dental formula: [4-5/7-8 (upper jaw), 8/2 (lower jaw)] (see figure below). Dorsal fin filamentous in males: II,8 (II,8). Anal fin: III,22-2A. Caudal fin non-filamentous. Gill rakers: 10-13. Scales: 28-30 (longitudinal line); 5 ½-6½ (above lateral line)/3½ (3½) (below lateral line); 10 around caudal peduncle. Lateral line scales: 27-30 tubes (see table below).
Nannopetersius mutambuei: mouth open in lingual view.
Nannopetersius mutambuei: morphometric and meristic data.
Maximum reported size: 107.4 mm SL (134.0 TL).
Colour: in life, general colour silvery with greenish dorsal region. Caudal and adipose fin bright red. Anal, pectoral, pelvic and dorsal-fin base yellowish; distal edge of fins reddish. Peripheral parts of iris reddish. Blackish opercular spot. No dark mid-lateral band visible in living specimens. In preserved specimens, general coulou brownish on dorsal midline and dorsal flank above black mid-lateral band, witish on ventral midline and ventral flank up to black mid-lateral band. Black mi-lateral band extending from posterior margin of operculum to caudal-fin base up to posterior edge of median caudal-fin rays. Humeral spot sometimes visible but often hidden by dark mid-lateral band.
Affinities: Nannopetersius mutambuei appears to be morphologically more similar to N. lamberti than to N. ansorgii. This is illustrated by a number of characters: the number of gill rakers on the ceratobranchial of the first branchial arch, which is 10-13 (10-12 in N. lamberti, 14-17 in N. ansorgii), the length of the longest dorsal-fin ray, 73.1-137.5 % head length (60.0-115.0 in N. lamberti, 55.0-110.0 in N. ansorgii) and the mid-lateral band, well visible along the entire length amongst preserved specimens (well visible in N. lamberti, not very distinct anteriorly, larger and more visible posteriorly on the caudal peduncle in N. ansorgii).
Distribution
Only known from the Inkisi River upstream of Sanga dam (lower Congo River basin), in Democratic Republic of the Congo (see also Faunafri).
IUCN assessment
Not evaluated.
Bibliography
