Heptapterus Bleeker, 1858

Depra, Gabriel de Carvalho, Aguilera, Gaston, Faustino-Fuster, Dario R., Katz, Axel M. & Azevedo-Santos, Valter M., 2022, Redefinition of Heptapterus (Heptapteridae) and description of Heptapterus carmelitanorum, a new species from the upper Parana River basin in Brazil, Zoosystematics and Evolution 98 (2), pp. 327-343 : 327

Genus Heptapterus Bleeker, 1858

Type species.

Pimelodus mustelinus Valenciennes, 1835.

Diagnosis.

Heptapterus differs from all other Heptapterini except Acentronichthys Eigenmann & Eigenmann, 1889, Nemuroglanis Eigenmann & Eigenmann, 1889, Chasmocranus bleekeri , ' Chasmocranus ' Chasmocranus brachynema Gomes & Schubart, 1958, ' Heptapterus ' Heptapterus multiradiatus , ' H. ' Heptapterus stewarti , and ' H. ' Heptapterus sympterygium by the presence of an adipose fin extensively fused with the caudal fin (Fig. 2 ). Heptapterus is distinguished from Acentronichthys by having a non-bifurcate caudal fin (i.e., caudal fin not divided in two lobes; vs. bifurcate, with distinct dorsal and ventral lobes), and from Nemuroglanis by having dark bars and stripes on back of trunk (vs. absence of dark bars and stripes on back of trunk) and 5-6 pairs of pleural ribs (vs. 8-9 ribs). It is also distinguished from ' C. ' Chasmocranus brachynema by having an elongate body, with a head length of 16.1-24.9% (vs. 25.5-27.3%); the posterior extension of mouth rim much shorter, with rictus barely reaching vertical line through posterior nostril (vs. posterior extension of mouth rim much longer, with rictus reaching vertical line between posterior nostril and eye); and the premaxillary tooth plate with no posterolateral extension, or with a small one (vs. with a very long posterolateral extension). It is further distinguished from C. bleekeri by having the pelvic-fin insertion posterior to vertical through insertion of dorsal fin (vs. anterior) and anal-fin insertion posterior to vertical through adipose-fin origin (vs. anterior). Additionally, Heptapterus differs from ' Heptapterus ' Heptapterus multiradiatus and ' H. ' Heptapterus stewarti by having fewer anal-fin rays (10-23 in Heptapterus vs. 38-46 and 33-36 in ' H. ' Heptapterus multiradiatus and ' H. ' Heptapterus stewarti , respectively). It is further distinguished from ' H. ' Heptapterus sympterygium by having the anal and caudal fins separated (vs. anal fin confluent with the caudal fin), and supraorbital pore 6 (s6) fused or closer to each other (vs. separate and closer to the eye than to each other).

Species included.

Heptapterus borodini (Mees & Cala, 1989), H. carmelitanorum , H. carnatus Faustino-Fuster, Bockmann & Malabarba, 2019, H. exilis Faustino-Fuster, Bockmann & Malabarba, 2019, H. hollandi (Haseman, 1911), H. mandimbusu Aguilera, Benitez, Terán, Alonso & Mirande, 2017, H. mbya Azpelicueta, Aguilera & Mirande, 2011, H. mustelinus (Valenciennes, 1835), H. ornaticeps Ahl, 1936, and H. qenqo Aguilera, Mirande & Azpelicueta, 2011.

Figures

Figure 2. Schematic representation of the different degrees of proximity and connection between the adipose and caudal fins in Heptapterini. a. Adipose and caudal fins widely separate, as in Imparfinis piperatus, for instance; b. Adipose fin reaching the caudal fin, but not connecting to it (i. e., connective tissue in which dorsal procurrent caudal-fin rays are imbedded is not contiguous with connective tissue forming the adipose fin), as in Chasmocranus longior, for instance; c. Adipose fin connecting with caudal fin (i. e., connective tissue in which dorsal procurrent caudal-fin rays are imbedded is clearly contiguous with connective tissue forming the adipose fin), as in Heptapterus.