Taxonomic Status and Redescription of the Gillbacker Sea Catfish (Siluriformes: Ariidae: Sciades parkeri)

The Gillbacker Sea Catfish is a valid species of ariid catfish from the northeastern coast of South America. There are many synonyms in the literature for the Gillbacker Sea Catfish and even recent classifications have used different scientific names. Examination of a wide range of sizes of individuals from different localities and examination of types and original species descriptions of Silurus parkeri, Bagrus flavescens, B. emphysetus, Arius physacanthus, A. bonneti, A. clavispinosus, and A. despaxi has lead us to the conclusion that all these names refer to the Gillbacker Sea Catfish and the valid name for the species is Sciades parkeri. The species is distinguished from all other ariid species by the following combination of features: body coloration yellow; swim bladder divided into three chambers, posterior chamber moderately sized; nuchal plate shield-shaped, usually larger than supraocciptal process; anterior notch of nuchal plate absent; head shield exposed and granulated in orbital and postorbital regions; lateral edge of accessory patches not emarginated or shallowly notched; fleshy furrow connecting posterior nares absent; and mesial gill rakers absent from first two gill arches. Striking intraspecific and/or ontogenetic variation in eye size, maxillary-barbel length, supraoccipital-process size, nuchal-plate size and shape, and dorsal-spine thickness contributed to the numerous synonyms and misidentifications for Sciades parkeri. Bagrus albicans, described from French Guiana, has at times been listed as a synonym of Sciades parkeri. Our examination of the holotype of B. albicans, however, led us to conclude that it is a synonym of Sciades proops.

Fig. 1

Sciades parkeri: (A) holotype (whereabouts unknown, 1016 mm TL; after Traill, 1832), (B) juvenile (MNHN 1936-0163, holotype of A. clavispinosus, 297 mm SL; photograph by C. Ferrara), (C) large adult (undeposited, 1023 mm SL; after Léopold, 2004, copyright Ifremer). NP, nuchal plate; W, width; L, length.

Fig. 2

Ventral view of swim bladder of (A–B) Sciades parkeri (holotype, whereabouts unknown, after Traill, 1832; MZUSP 48524, 273 mm SL; respectively), (C) S. proops (MZUSP 52844, 264 mm SL), and (D) Notarius quadriscutis (MZUSP 48525, 188 mm SL). AC, anterior chamber; MC, middle chamber; PC, posterior chamber.

Fig. 3

Dorsal view of posterior portion of skull of (A) Sciades parkeri (MNHN A-8566, holotype of Bagrus flavescens, 760 mm SL) and (B–C) S. proops (MNHN A-9331, syntype of B. proops, 535 mm SL; MNHN A-9350, holotype of B. albicans, 589 mm SL; respectively). NP, nuchal plate; SP, supraoccipital process; AN, anterior notch (photographs A and C by C. Ferrara).

Fig. 4

Tooth patches on palate of (A–B) Sciades parkeri (MNHN A-8566, holotype of Bagrus flavescens, 760 mm SL; MNHN 1936-0162, holotype of Arius bonneti, 327 mm SL; respectively), (C–D) S. proops (MNHN A-9350, holotype of B. albicans, 589 mm SL; MNHN B-0618, syntype of B. proops, 204 mm SL; respectively), (E) S. couma (MNHN A-9338, syntype of B. couma, 615 mm SL), (F) S. herzbergii (after Acero P., 2002), and (G) S. passany (MNHN A-9399, holotype of B. passany, 860 mm SL). LN, lateral notch.

Fig. 5

Allometric trends for selected features in Sciades parkeri. Holotype datum denoted with gray square.

Contributor Notes

Associate Editor: C. J. Ferraris.

¹ Department of Biological Sciences, Auburn University, 331 Funchess Hall, Auburn, Alabama 36849, e-mail: betanri@auburn.edu. Send reprint requests to this address.

² Museu de Zoologia da Universidade de São Paulo, Caixa Postal 42494, CEP 04218-970, São Paulo, SP, Brazil, e-mail: a_marceniuk@hotmail.com.

³ Núcleo Integrado de Biotecnologia, Universidade de Mogi das Cruzes, CEP 08780-911 Mogi das Cruzes, SP, Brazil.

⁴ Muséum National d'Histoire Naturelle, 55 Rue Buffon, Case Postale 56-75005, Paris, France, e-mail: bearez@mnhn.fr.

Received: 27 Sept 2007

Accepted: 09 May 2008