Editorial Type:
Article Category: Research Article
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Online Publication Date: 01 Aug 2005

Brachyplatystoma capapretum: a New Species of Goliath Catfish from the Amazon Basin, with a Reclassification of Allied Catfishes (Siluriformes: Pimelodidae)

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Page Range: 492 – 516
DOI: 10.1643/CI-04-036R1
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Abstract

Brachyplatystoma capapretum n. sp., a pimelodid catfish from the Amazon River, is described and diagnosed by its fine, densely spaced outer jaw teeth and relatively few rows of straight, depressible inner teeth; juveniles with large dark blotches on and above lateral line; adults with exceptionally dark pigmentation dorsally, abruptly countershaded near lateral line; broad, shallowly forked caudal fin. The systematic position of the new species was investigated with a maximum parsimony phylogenetic analysis of morphological characters. The resulting cladograms identify a nested set of unambiguous characters supporting the following monophyletic groups and taxonomic recommendations. Brachyplatystomatini new tribe is established for Brachyplatystoma and Platynematichthys and supported by two synapormorphies: two-chambered gas bladder connected by paired lateral tubes; cleithrum with blade-like ventral crest between pectoral spine articulation and posterior process of cleithrum. The monotypic genera Goslinia and Merodontotus are placed in synonymy with Brachyplatystoma characterized here by two synapomorphies: suspensorium greatly expanded mediodorsally, forming a massive plate approaching parasphenoid; juveniles with greatly elongated caudal-fin filaments developed from single outermost, unbranched principal rays. Bleeker's genus group name Malacobagrus is employed as a subgenus within Brachyplatystoma to include B. filamentosum, B. capapretum, and B. rousseauxii. Monophyly of Malacobagrus is supported by five synapomorphies: adults developing extensive reticulated system of lateralis tubules on body; Weberian complex with thick, ventral bony platform at gas bladder attachment; subquadrangular shape of opercle; pectoral spine with sulcus along anterior edge; small, non-sutured endopterygoid. Two unique synapomorphies place B. capapretum and B. filamentosum together as sister species: juveniles with spots on and above lateral line; caudal peduncle subcircular in cross-section.

Resumen

Brachyplatystoma capapretum n. sp., um novo bagre pimelodídeo do rio Amazonas é aqui descrito e diagnosticado por sua dentição finamente granulada e densa das maxilas, e presença de uma estreita faixa interna de dentes depressíveis; jovens com grandes manchas sobre e acima da linha lateral; adultos com colorido do dorso excepcionalmente escuro acima da linha lateral, contrastando com o ventre abruptamente claro; nadadeira caudal larga e levemente furcada nos adultos. A posição sistemática desta nova espécie foi investigada por uma análise de máxima parcimônia de caracteres morfológicos. O cladograma resultante identificou uma série de características não ambíguas que sustentam a monofilia dos seguintes grupos e recomendações taxonômicas. Brachyplatystomatini nova tribo é estabelecida para os gêneros Brachyplatystoma e Platynematichthys, suportada por duas sinapomorfias: bexiga natatória com duas câmaras conectadas por um par lateral de tubos, cleitro com uma quilha ventral laminar entre a articulação do acúleo e o processo posterior do cleitro. Os gêneros monotípicos Goslinia e Merodontotus são colocados na sinonímia de Brachyplatystoma, caracterizado por duas sinapomorfias: suspensorium muito expandido dorso-medialmente, formando uma placa maciça que se aproxima do paresfenóide; jovens com dois filamentos caudais muito alongados, constituídos somente pelos raios principais caudais superior e inferior. Malacobagrus Bleeker (1862) é empregado como um sub-gênero de Brachyplatystoma e inclui B. filamentosum, B. capapretum e B. rousseauxii. A monofilia de Malacobagrus é sustentada por cinco sinapomorfias: extensa rede de túbulos anastomosados da linha lateral cobrindo o corpo de adultos; uma plataforma óssea onde se acopla a bexiga natatória, posterior ao aparelho de Weber; formato subquadrangular do opérculo; acúleo peitoral com sulco na margem anterior; e endopterigóide pequeno e não suturado. Duas sinapomorfias sustentam a proposição de B. capapretum e B. filamentosum como espécies irmãs: jovens com manchas acima e na linha lateral; pedúnculo caudal com secção de formato subcircular.

Copyright: The American Society of Ichthyologists and Herpetologists
 Fig. 1. 
 Fig. 1. 

The species of Platynematichthys and Brachyplatystoma, computer drawings based on photographs of fresh adults and preserved museum specimens. Del. K. Luckenbill

 Fig. 2. 
 Fig. 2. 

Juveniles of (A) Brachyplatystoma capapretum, INPA 10302, 136 mm SL, paratype. Scale bar = 1 cm. (B) Brachyplatystoma capapretum, ANSP 178524, 255 mm SL, larger specimen retaining juvenile spots evident posterior to dorsal fin but dorsal pigmentation bleached out below and anterior to dorsal fin. Scale bar = 2 cm. (C) Brachyplatystoma filamentosum, ANSP 179774, 119 mm SL. Scale bar = 1 cm

 Fig. 3. 
 Fig. 3. 

Strict consensus tree of six most parsimonious trees resulting from phylogenetic analysis of morphological data on the Pimelodidae emphasizing relationships and character support for Platynematichthys and species of Brachyplatystoma. Numbers above branches subtending B. capapretum and B. filamentosum are Bremer support values and unambiguous character transformations leading to synapomorphies are listed below branches

 Fig. 4. 
 Fig. 4. 

Gas bladders in ventral view of (A) Pimelodus blochii, ANSP L76–20, 88 mm SL. Scale bar = 5 mm; (B) Platynematichthys notatus, DU F938, 155 mm SL. Scale bar = 5 mm; (C) Brachyplatystoma capapretum, from an uncatalogued fresh specimen collected with INPA specimens 21912–21914, ca. 580 mm SL. Scale bar = 2 cm; (D) Brachyplatystoma platynemum, from an unnumbered line drawing in Miranda Ribeiro, 1918. CM = constrictor muscles, AC = anterior chamber, PC = posterior chamber, LT = lateral tubes

 Fig. 5. 
 Fig. 5. 

Cleithra, in left side lateral view with anterior toward upper left, of (A) Platynematichthys notatus, ANSP 178258. Scale bar = 5 mm; (B) Brachyplatystoma filamentosum, DU F1052. Scale bar = 1 cm; (C) Leiarius longibarbis, ANSP 178256. Scale bar = 5 mm. VC = ventral cleithral crest, PP = posterior cleithral process

 Fig. 6. 
 Fig. 6. 

Articulated suspensoria of (A) Brachyplatystoma filamentosum, in lateral view, (B) in ventral view, DU F1052; (C) Brachyplatystoma vaillantii, in ventral view, DU F1109; (D) Platynematichthys notatus, in ventral view, ANSP 178258. Scale bars = 1 cm. HYO = hyomandibula, MPT = metapterygoid, POP = preopercle, Q = quadrate

 Fig. 7. 
 Fig. 7. 

Dentition of premaxilla and palate in ventral view of (A) Brachyplatystoma filamentosum, DU F1052; (B) Brachyplatystoma capapretum, MZUSP 53262. Scale bars = 1 cm. PT = pterygoid tooth plate, EN = endopterygoid, VT = vomerine teeth

 Fig. 8. 
 Fig. 8. 

Holotype of Brachyplatystoma capapretum, MZUSP 78481, 581 mm SL; (A) lateral view; (B) dorsal view of head and anterior trunk; (C) ventral view of head and anterior trunk; (D) reticulated network of lateralis sensory canals in skin along side below dorsal fin

 Fig. 12. 
 Fig. 12. 

Pectoral spines in anterior view of (A) Brachyplatystoma filamentosum, DU F1052; (B) Brachyplatystoma vaillantii, ANSP 179474. Scale bars = 5 mm

 Fig. 9. 
 Fig. 9. 

Spot map of collection localities for Brachyplatystoma capapretum, some single squares include multiple individuals, and star indicates type locality. Base map of drainages and elevations provided by Conservation Science Program, World Wildlife Fund US; inset keys shading of elevations below 200 m where the species occurs

 Fig. 10. 
 Fig. 10. 

Weberian complex of Brachyplatystoma filamentosum, DU F1052, in (A) lateral view; (B) ventral view. Scale bar = 1 cm. PGB = gas bladder platform

 Fig. 11. 
 Fig. 11. 

Opercle bones in lateral view of (A) Brachyplatystoma capapretum, MZUSP 53262; (B) Brachyplatystoma vaillantii, DU F1198. Scale bars = 5 mm

Contributor Notes

(JGL) Department of Ichthyology, The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania 19103; and (AA) Museu De Zoologia Da Universidade De São Paulo, Avenida Nazaré, Caixa Postal 42594, São Paulo-Sp 04299–970, Brazil. (JGL) lundberg@acnatsci.org; and (AA) aakama@ib.usp.br Send reprint requests to JGL.

Accepted: 21 Feb 2005
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