Editorial Type:
Article Category: Research Article
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Online Publication Date: 17 Dec 2010

Revision of Panaque (Panaque), with Descriptions of Three New Species from the Amazon Basin (Siluriformes, Loricariidae)

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Page Range: 676 – 704
DOI: 10.1643/CI-09-185
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Abstract

The Panaque nigrolineatus group (subgenus Panaque) is revised; three nominal species—P. cochliodon, P. nigrolineatus, and P. suttonorum—are redescribed and three new species are described. Panaque armbrusteri, new species, is widespread in the Tapajós River and its tributaries in Brazil and is distinguished by having a supraoccipital hump, higher numbers of jaw teeth and an ontogenetic increase in interpremaxillary and intermandibular tooth-row angles, relatively short paired-fin spines, and dorsal margin of infraorbital six flared laterally. Panaque schaeferi, new species, is widespread in main-channel habitats of the upper Amazon (Solimões) River basin in Brazil and Peru; it is distinguished by having a coloration consisting of dark or faded black spots evenly distributed on a pale gray to brown base, and by its large adult body size (>570 mm SL). Panaque titan, new species, is distributed in larger, lowland to piedmont rivers of the Napo River basin in Ecuador, and is distinguished by having a postorbital pterotic region bulged beyond the ventral pterotic margin, coloration consisting of irregular and widely spaced dark gray to brown stripes on light brown to tan base, and large adult body size (>390 mm SL). A relatively large pterotic, indicative of an enlarged gas bladder and gas bladder capsule, and allometric increases in tooth number are hypothesized to be synapomorphies uniting members of the subgenus Panaque.

Resumen

Se revisó el grupo Panaque nigrolineatus (subgénero Panaque); se redescriben tres especies nominales—P. cochliodon, P. nigrolineatus, and P. suttonorum—y tres nuevas especies son descritas. Panaque armbrusteri n. sp. tiene amplia distribución en el río Tapajós y sus tributarios en Brasil y se distingue por tener una joroba supraoccipital, un gran número de dientes mandibulares y un incremento ontogénico en el ángulo de la hilera de dientes interpremaxilares e intermandibulares, espinas de las aletas pares relativamente cortas, y el margen dorsal del sexto infraoccipital hinchado lateralmente. Panaque schaeferi n. sp. se distribuye ampliamente en hábitats del canal principal de la cuenca del río alto Amazonas (Solimões) en Brasil y Perú; se distingue por tener una coloración que consiste en puntos negros oscuros o descoloridos uniformemente distribuidos sobre un color gris pálido a marrón base, y por el gran tamaño corporal de los adultos (>570 mm SL). Panaque titan n. sp. presenta distribución más amplia, desde la llanura hasta los ríos de pie de monte de la cuenca del río Napo en Ecuador, y se distingue por tener una región pterótica postorbital hinchada detrás del margen ventral pterótico, coloración que consiste en rayas irregulares y ampliamente espaciadas de color negro a marrón sobre marrón claro a un color bronceado base, y tamaño grande del cuerpo en adultos (>390 mm SL). La presencia de un pterótico relativamente grande que es indicador de una agrandada vejiga gaseosa y su cápsula extendida, y el aumento allometrico del número de dientes suponen ser sinapomorfías que unen a los miembros del subgénero Panaque.

Copyright: 2010 by the American Society of Ichthyologists and Herpetologists
Fig. 1
Fig. 1

Holotype of Panaque armbrusteri, new species, MZUSP 95465, 344.7 mm SL, Brazil, Mato Grosso State, Tapajós River drainage, Teles Pires River, near the highway MT-416 ferry, 9°27′07″S, 56°30′46″W, 27 September 2007 (photos by L. M. Sousa).

Fig. 2
Fig. 2

Oral disks of Panaque armbrusteri, new species, paratypes (A) ANSP 182811, 114 mm SL, (B) MZUSP 96388, 172 mm SL, and non-type (C) MNRJ 34091, 323 mm SL, showing ontogenetic increase in interpremaxillary and intermandibular tooth row angles.

Fig. 3
Fig. 3

(A) Premaxillary and (B) dentary tooth number and (C) cheek odontode number versus standard length of Panaque nigrolineatus (circles), P. armbrusteri, new species (squares), P. titan, new species (diamonds), and P. schaeferi, new species (stars). Significant relationships between premaxillary and dentary tooth number and standard length of P. armbrusteri and P. nigrolineatus described by respective upper and lower dashed lines in (A) and (B). Significant relationships between cheek odontode number and standard length of P. nigrolineatus and P. schaeferi described by respective dashed and dotted lines in (C).

Fig. 4
Fig. 4

Paratype of Panaque armbrusteri, new species, MZUSP 96326, 180 mm SL, Brazil, Mato Grosso State, Tapajós River drainage, right bank tributary of the Peixoto de Azevedo River, 10°17′14″S, 54°50′57″W, 17 October 2007 (photographed alive).

Fig. 5
Fig. 5

Posterior head and anterior trunk region of paratype of Panaque armbrusteri, new species, ANSP 182812, 224 mm SL, illustrating supraoccipital hump, pterotic lacking postorbital bulge, and the dorsal half of infraorbital six flared laterally. Scale bar  =  11 mm.

Fig. 6
Fig. 6

Circumorbital plates and bones of holotype of Panaque titan, new species, MEPN 9507, 394 mm SL, illustrating 1) preorbital crest composed ventrally of infraorbital plates three to five and dorsally of prefrontal plate, 2) postorbital bulge, and 3) dorsal margin of infraorbital six flared laterally. Abbreviations: cl, cleithrum; f, frontal, io3–io6, infraorbitals three through six; mv1, midventral plate one; pf, prefrontal plate; pt, pterotic; sp, sphenotic. Scale bar  =  17 mm.

Fig. 7
Fig. 7

Anterolateral view of dorsal, middorsal, lateral median, and midventral caudal peduncle plates of holotype of Panaque titan, new species, MEPN 9507, 394 mm SL, illustrating enlarged trunk plate odontodes arranged as a row or rows. Inset view of enlarged odontode rows in dorsal view.

Fig. 8
Fig. 8

Distribution of Panaque (Panaque) species. P. armbrusteri (squares), P. cochliodon (triangles), P. nigrolineatus (open and filled circles), P. schaeferi (stars), P. suttonorum (cross), P. titan (diamonds), and congeneric populations that we are aware of but either did not examine in this study or that we suspect may represent additional, undescribed species: Panaque cf. nigrolineatus (circle with “+”), and Panaque cf. armbrusteri (circles with “×”). Symbols may represent more than one locality. Open symbols indicate type localities.

Fig. 9
Fig. 9

Syntype of Chaetostomus cochliodon, NMW 47297, 229 mm SL, Cauca River, Colombia (photos by J. W. Armbruster).

Fig. 10
Fig. 10

Illustrations of (A) Panaque cochliodon (reproduced from Steindachner, 1880:pl. 4, modified by flipping horizontally); (B) P. nigrolineatus (reproduced from Peters, 1877:556); and (C) paratype of Panaque titan, new species, FMNH 97591, 145.1 mm SL (original illustration by C. Richardson).

Fig. 11
Fig. 11

Syntype of Chaetostomus nigrolineatus, ZMB 10046, 303 mm SL, Calabozo, Venezuela (photos by M. Allen). Scale bar  =  60 mm.

Fig. 12
Fig. 12

Holotype of Panaque schaeferi, new species, MUSM 27500, 576 mm SL, Peru, Ucayali Department, Padre Abad Province, Aguaytia River drainage, Santa Ana River, Cordillera Azul National Park, 08°29′51″S, 75°33′36″W, 250 m elevation, December 2006. Scale bar  =  100 mm.

Fig. 13
Fig. 13

(A) Uncatalogued specimen of Panaque schaeferi, new species, from the Amazon River main channel near Santarem, Brazil (photographed alive by M. Goulding); (B) paratype of Panaque schaeferi, new species, MUSM 28505, 559 mm SL, Ucayali, Peru.

Fig. 14
Fig. 14

Holotype of Panaque suttoni, USNM 121033, 278 mm SL, Negro River below Yasa River mouth, Maracaibo Lake basin, Venezuela (photos by S. Raredon). Scale bar  =  50 mm.

Fig. 15
Fig. 15

Uncatalogued specimen of Panaque suttonorum from the Zulia River, Venezuela (photographed alive by D. Taphorn).

Fig. 16
Fig. 16

Holotype of Panaque titan, new species, MEPN 9507, 394 mm SL, Ecuador, Sucumbíos Province, Napo River drainage, Apoalla Creek, tributary of the lower Shushufindi River, 0°17′S, 76°27′W, 24 November 1983.

Contributor Notes

1 Department of Biology, Auburn University, Auburn, Alabama 36849, Present address: Department of Wildlife and Fisheries, 215 Old Heep Hall, Texas A&M University, College Station, Texas 77840; E-mail: nklujan@gmail.com. Send reprint requests to this address.
2 Departamento de Ictiología, Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Apartado, 14-0434, Lima 14, Peru; E-mail: maxhhidalgo@gmail.com
3 Department of Environmental and Forest Biology, College of Environmental Science and Forestry, State University of New York, Syracuse, New York 13210; E-mail: djstewart@esf.edu

Associate Editor: R. E. Reis.

Received: 11 Oct 2009
Accepted: 21 Jul 2010
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