New Rineloricaria

[Silurus]

Rodriguez, M & A Miqualarena, 2008. Rineloricaria isaaci (Loricariidae: Loricariinae), a new species of loricariid catfish from the Uruguay River basin. Journal of Fish Biology 73: 1635–1647.

Abstract
Rineloricaria isaaci is described from tributaries of the Uruguay River basin in Argentina, Brazil and Uruguay. The new species is distinguished by having a long and wide area of naked skin at the snout tip, surpassing the anteriormost pore of the infraorbital ramus of the sensory canal, approximately in the middle of the third postrostral plate, and by its particular sexual dimorphism characterized by the long pectoral and pelvic fins of mature males.

[bekateen]

Figure 2

FIG. 2. Naked area of snout in (a)

Rineloricaria quadrensis

and (b)

Rineloricaria longicauda

(modified from Reis, 1983) and (c)

Rineloricaria isaaci

sp. nov. Scale: 1 mm. Od, odontodes; NA, naked area.

The photos below show that male Rineloricaria isaaci develop really long pelvic fins compared to females and compared to males of the other species shown:

Figure 3

FIG. 3. Sexual dimorphism in pectoral and pelvic fins in mature males of: (a)

Rineloricaria isaaci

sp. nov., MACN-Ict 8969, holotype, 106.1 mm standard length (LS), (b)

Rineloricaria microlepidogaster

, MCP 34764, 137.4 mm LS, (c)

Rineloricaria cadeae

, MCP 34728, 98.5 mm LS and (d)

Rineloricaria aequalicuspis

, MCP 26910, 168.3 mm LS.

Figure 6

FIG. 6. Sexual dimorphism in the pectoral and pelvic fins in

Rineloricaria isaaci

sp. nov. (a) female, ILPLA 1716, paratype, 101.8 mm standard length (LS) and different grades of maturity of males: (b) ILPLA 1716, paratype, 96.4 mm LS, (c) MCP 10380, paratype, 100.4 mm LS and (d) MACN-Ict 8969,
holotype, 106.1 mm LS.