Characiformes

Moritz, Timo, Buchert, Jan & Schnell, Nalani K, 2019, Unexpected diversity of median caudal cartilages in teleosts, Zoological Journal of the Linnean Society 186 (3), pp. 599-632 : 609

Characiformes ( Fig. 4 )

Out of the 18 species, representing eight families, only two characid species have median caudal cartilages. However, not all investigated specimens of those two species showed such cartilages. In Gymnocorymbus ternetzi five out of seven specimens had a very small comma-like cartilage at the lower distal edge of hypural 3 ( Fig. 4A ). It does not appear to be associated with the lowest ray of the upper caudal lobe, which inserts more ventral in the diastema. In Hemigrammus erythrozonus a roundish to oval, small cartilage can be present at about the same position ( Fig. 4B, C ). However, in this species the lowest ray of the upper caudal lobe inserts in this area, so that the cartilage is somewhere between the bases of the hemitrichs. The hemitrichs in both species may be prolonged in anterior direction, but do not show any medially directed pegs pointing to each other.

Figures

Figure 4. Cleared and stained caudal fins in the area of the diastema of Characiformes: A, Gymnocorymbus ternetzi, DMM IE/11063, 25.7 mm SL; B, Hemigrammus erythrozonus, DMM IE/11065, 17.3 mm SL; C, Hemigrammus erythrozonus, DMM IE/11066, 20.5 mm SL; all lateral views. Abbreviations: cmc, median caudal cartilage; hu, hypural; lfu, lowest ray of upper caudal lobe; ufl, upper most ray of lower caudal lobe.