Editorial Type:
Article Category: Research Article
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Online Publication Date: 18 Dec 2012

A New Species of Potamorrhaphis (Beloniformes: Belonidae) from the Amazon Basin

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Page Range: 663 – 669
DOI: 10.1643/CI-12-032
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A new species of Potamorrhaphis is described from the Amazon basin in Brazil and Peru. Potamorrhaphis labiatus, new species, is distinguished from P. guianensis and P. eigenmanni by having the posterior third of the labial membrane highly expanded laterally, reaching to or passing the level of the ventral margin of the maxilla when folded ventrally, and from P. petersi by having fewer dorsal- and anal-fin rays and a deeper caudal peduncle. A key for the species of Potamorrhaphis is provided.

Uma nova espécie de Potamorrhaphis é descrita da bacia do rio Amazonas no Brasil e no Peru. Potamorrhaphis labiatus n. sp. se distingue de P. guianensis e P. eigenmanni por ter o terço posterior da membrana labial fortemente expandida lateralmente, alcançando ou ultrapassando o nível da margem ventral da maxila quando virada para baixo, e de P. petersi pelo menor número de raios nas nadadeiras dorsal e anal e pelo pedúnculo caudal mais alto. Uma chave de identificação para as espécies de Potamorrhaphis é fornecida.

Copyright: 2012 by the American Society of Ichthyologists and Herpetologists
Fig. 1.
Fig. 1.

Morphometric variables used in Table 1 and in the multivariate analyses: body length* (BL—measured from the anterior margin of nasal bone to the hypural plate); trunk length* (TL—measured from the posterior margin of opercle to hypural plate); predorsal length (PD—measured from the anterior margin of nasal bone to the origin of dorsal fin); preanal length (PA—measured from the origin of the isthmus to the anal-fin origin); cranial length (CL—measured from the anterior margin of nasal bone to the posterior margin of supraoccipital bone); head length* (HL—measured from the anterior margin of nasal bone to the posterior margin of the opercle); head depth (HD—measured right after the orbit); preorbital length* (PrO—measured from the anterior margin of the dentary to the anterior margin of the orbit); postorbital length (PsO—measured from the posterior margin of the orbit to the posterior margin of opercle); snout length (SnL—measured from the anterior margin of the nasal bone to the anterior margin of the orbit); eye diameter (ED—measured horizontally between anterior and posterior orbital margins); interorbital distance (IO—measured horizontally between orbits); body depth and body width** (BD and BW—measured at the dorsal-fin origin); pectoral to pelvic fin distance* (P1-P2—measured from the ventral origin of pectoral fin to lateral origin of pelvic fin); pelvic to dorsal distance (P2-D—measured from the lateral origin of pelvic fin to the dorsal-fin origin); dorsal to anal fin distance (D-A—measured from the origin of dorsal fin to the anal-fin origin); anal to pelvic fin distance (P2-A—measured from the lateral origin of pelvic fin to the anal-fin origin); caudal peduncle depth (CP—measured just anterior to the procurrent caudal-fin rays). *Excluded from the multivariate analyses. **Used in the analyses but not shown in this figure.

Fig. 2.
Fig. 2.

Holotype of Potamorrhaphis labiatus, MCP 46290, male, 136.2 mm BL, Brazil, Amazonas, Carauari, Rio Juruá, beach 2 km upstream Sacado do Juburi.

Fig. 3.
Fig. 3.

Paratype of Potamorrhaphis labiatus, UFAM 646, 120.7 mm BL, Brazil, Amazonas, Carauari, Rio Juruá, lake at Rio Juruá in Carauari harbor. Photograph courtesy of L. Malabarba.

Fig. 4.
Fig. 4.

Schematic illustration of lip morphology of Potamorrhaphis. (A) Potamorrhaphis labiatus; (B) P. guianensis. LM, labial membrane; MX, maxilla.

Fig. 5.
Fig. 5.

Schematic illustration of branchiostegal membrane: (A) Potamorrhaphis labiatus; (B) P. guianensis. Scale bar 2 mm.

Fig. 6.
Fig. 6.

Schematic illustration of dentary coronoid process: (A) Potamorrhaphis labiatus and (B) P. guianensis. Scale bar 2 mm.

Fig. 7.
Fig. 7.

Genital papilla of Potamorrhaphis labiatus, in ventral view: (A) female, MCP 46291; (B) male, MCP 46290. Scale bar 1 mm.

Fig. 8.
Fig. 8.

Distribution of Potamorrhaphis labiatus in the Amazon basin. Star indicates type locality.

Fig. 9.
Fig. 9.

Canonical Component Analysis of three species of Potamorrhaphis: dots  =  Potamorrhaphis labiatus, triangles  =  P. eigenmanni, squares  =  P. guianensis. Arrows indicate type specimens.

Contributor Notes

Associate Editor: D. Buth.

Received: 05 Mar 2012
Accepted: 06 Jul 2012
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