Tricuspidalestes
A distinctive feature of Tricuspidalestes is that it never possess more than three dentary cuspids. Parietal fontanel is present. The lateral line is incomplete. There are two rows of teeth on the lower jaw. The inner one has two cone-shaped teeth. This genus is monospecific.
Synonym
Phenacogrammus Eigenmann, 1907 (partim)
Type species: Tricuspidalestes caeruleus
Phenacogrammus caeruleus Matthes, 1964 by subsequent designation of Poll, 1967.
Currently, Tricuspidalestes is monospecific.
Tricuspidalestes caeruleus (Matthes, 1964)
Type and type locality
Phenacogrammus caeruleus Matthes, 1964: 53-56, pl. IIa, b. Type locality: “Rivière Bateli”. Holotype: MRAC 138534; paratypes: MRAC 138535-138561, 138563-138594.
Synonyms
Phenacogrammus caeruleus Matthes, 1964
Tricuspidalestes caeruleus Poll, 1967
Common names
Estonian: Lasuurtetra
Finnish: Sinirihmatetra
Description
Diagnosis: body depth 3.35-3.9 (3.25-3.95) and head length 3.5-3.8 (3.4-3.8) in standard length. Prominent lower jaw. Parietal fontanel present. Dental formula: [4/8-10 (upper jaw), 10-12/2 (lower jaw)], [4/8-10 (upper jaw), 10-12/2 (lower jaw)], including 2 lower internal teeth. Alternating external premaxillary teeth. Cuspids number, upper jaw, external row: 3, internal row: 3 (3); lower jaw, external row 3 (from 2 to 5), internal row 1. Every teeth are tricuspidate except internal mandibulary teeth and decreases in size from symphysis, at both lower and upper jaws. Dorsal fin filamentous: II,8 (II,8). Anal fin: III,17-20 (III-IV,16-20). Fins are filamentous including caudal and pelvic fins. Gill rakers on the lower limb of the first gill arch: 19-22 (18-23). Longitudinal line scales: 35-40 + 1-2 (36-41); transversal line scales: 7½-8½ (above lateral line)/3½-4½ (below lateral line) (7½-8½/3½-4½) (more than 6.½ scales above the lateral line); scales around caudal peduncle 16-18 (16-18). Lateral line incomplete: 3-5 (3-6) tubes.
Maximum reported size: 44 mm S.L.
Colour: a thin mid-lateral black line. Fins partly blackish, especially pectoral fins.
Distribution
Endemic to 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.
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