Bunocephalus erondinae , a new species of banjo catfish from southern Brazil ( Siluriformes : Aspredinidae )

Bunocephalus erondinae, a new species of banjo catfish is described from the laguna dos Patos system, Rio Grande do Sul, Brazil. The new species differs from its congeners by the bony epiphyseal bar very wide (vs. narrow). Bunocephalus erondinae is externally most similar to Bunocephalus doriae (rio Uruguay and rio Paraná-Paraguay basins), however, differs from this species by the following characters: the bony epiphyseal bar very wide (vs. narrow); metapterygoid round, width is equal the height (vs. metapterygoid elongate, width lesser than half of height), well developed lamina in the hypohyal and anterior ceratohyal bones (vs. little developed or absent), 32 vertebrae (vs. 34-35), first procurrent caudal-fin rays well developed (vs. vestigial), vertebral parapophysis 5 distally expanded, shaped like an axe (vs. not expanded).

In the present paper a new species of Bunocephalus from laguna dos Patos system, south Brazil is described.

Material and Methods
Measurements were taken point to point with a digital caliper in dorsal, ventral, and lateral view of specimens.Measurements are expressed as percents of standard length (SL), except subunits of head, expressed as percents of head length (HL).The measurements are: standard length (measured from snout tip to caudal-fin origin); head length (measured between snout tip and posterior tip of supraoccipital bone); predorsal length (measured between snout tip and dorsal-fin origin); length of unbranched dorsalfin ray (measured between its insertion and its distal tip); pectoral-fin spine length (measured between its insertion and its distal tip); length of unbranched pelvic-fin ray (measured between its insertion and its distal tip); length of uppermost unbranched caudal-fin ray (measured between its insertion and its distal tip); length of lowermost unbranched caudal-fin ray (measured between its insertion and its distal tip); abdominal length (measured between insertion of pectoral spine and insertion of unbranched pelvic-fin ray); post-abdominal length (measured from pelvic-fin insertions to anal-fin origin along ventral midline); cleithral width (measured between the lateralmost margins of contralateral cleithra); distance between coracoid processes (measured between distal tips of coracoid processes); length of coracoid process (measured between its origin and its distal tip); body depth at dorsal-fin origin (measured between dorsal-fin origin and ventral body surface); caudal-peduncle length (measured between insertion of first unbranched anal-fin ray and caudal-fin origin); caudal-peduncle depth (measured vertically from last unbranched anal-fin ray to dorsal body surface); caudalpeduncle width (measured as greatest horizontal peduncle width coequal with last unbranched anal-fin ray); anal-fin base length (measured between insertion of first unbranched anal-fin ray and insertion of last branched anal-fin ray); head depth (measured through a vertical between posterior margin of supraoccipital and ventral body surface); snout length (measuread between snout tip and lachrymal margin of orbit); interorbital width (measured between orbits dorsally); distance between anterior nostrils; distance between posterior nostrils; distance between maxillary barbels (measured between origins of maxillary barbels); distance between anterior mental barbels (measured between origins of anterior mental barbels); distance between posterior mental barbels (measured between origins of posterior mental barbels); and mouth width (measured at mouth gape).Counts are as followns: number of dorsal-fin rays; number of pectoral-fin rays; number of pelvic-fin rays; number of anal-fin rays, number of caudal-fin rays, and number of vertebrae.Vertebral counts include all vertebrae (including the first five vertebrae modified as the Weberian apparatus and complex vertebra).The compound caudal centrum (PU1+U1) was counted as one element following Lundberg & Baskin (1969).Anatomical descriptions and illustrations are made after dissection of cleared and stained specimens (c&s) prepared according to the method of Taylor & van Dyke (1985).Nomenclature of the bony structures follows de Pinna (1996).All morphological observations were made under a Zeiss SV8 microscope and anatomical illustrations were sketched using a camera lucida.

Bunocephalus erondinae, new species
Fig. 1 Diagnosis.Bunocephalus erondinae differs from its congeners by the bony epiphyseal bar very wide (vs.narrow; Fig. 2).Also B. erondinae is distinguished from B. doriae by the tip of the vertebral parapophysis 5 expanded with the shape of an axe (vs.not expanded, Fig. 2), metapterygoid round, as the width is equal (vs.metapterygoid elongate, as the width lesser than half of height, Fig. 3), well developed lamina on hypohyal and on the anterior ceratohyal bones (vs.little developed or absent, Fig. 4), first procurrent caudal-fin rays well developed (vs.vestigial, Fig. 5   prominent relative to lower lip.All barbels simple, unbranched; maxillary barbel reaching slightly last pectoral-fin spine insertion; posterolateral mental barbel twice as long as anteromedial barbel.Opercular opening reduced to small valvular slit just anterior to pectoral-fin spine insertion.Dorsal-fin rays i,4.Dorsal-fin spinelet absent.Last dorsalfin ray not adnate to body, membrane between last dorsalfin ray and body small.Pectoral-fin rays I,5.Pelvic-fin rays i,5, fourth ray longest but not reaching anal-fin origin; pelvic splint absent.Adipose fin absent.Anal-fin rays ii,5-ii,7, membrane between last anal-fin ray and body small.Caudalfin rays i,8,i; rounded.Caudal-fin unbranched rays shorter than branched rays; two procurrent rays on upper and lower lobe, respectively.Lateral-line canal complete but rarely reaching caudal-fin origin.Total vertebrae 32.
Color in alcohol.Head light brown; body with three dark brown saddles on a light brown base; first saddle at dorsalfin, and two saddles on posterior body, saddles may fuse and expand ventrally and laterally to give appearance of light brown dorsal patches on dark brown base; anterior ventral surface much lighter than dorsal surface; pectoral-fin brown with light distal margin; ventral and anal fins whitish with dark blotches; and dorsal and caudal-fins dark gray with light distal margin.All barbels brown with dark blotches.
Distribution.Known from several tributaries to the laguna dos Patos system, Rio Grande do Sul, Brazil (Fig. 6).
Etymology.The specific name, erondinae, is given in memory to my mother Erondina Rodrigues Cardoso.

Discussion
Of the valid species of Bunocephalus (Friel, 2003), that remained after Friel's (2008) Boulenger (1902), whose type-locality is Villa Rica, Paraguay, and Posadas rio Paraná, Argentina.Forty years after the description of B. doriae, Eigenmann & Allen (1942) described Bunocephalus retropinnis, with syntypes from Cacequi, Rio Grande do Sul, Brazil.They distinguished B. retropinnis from all other species by the posterior position of the dorsal-fin, with the origin is closer to caudal-fin than snout.Mees (1988Mees ( , 1989) ) recognized B. retropinnis as Dysichthys doriae (= Bunocephalus doriae).I examined one specimen of B. doriae from the Cacequi region, type-locality of B. retropinnis, collected in a small tributary to the rio Santa Maria, rio Ibicuí drainage, Rosário do Sul, RS, and some additional specimens from this drainage.I found no differences between these specimens and all other specimens from the rio Uruguay drainage, indicating that B. retropinnis should indeed be a synonym of B. doriae, corroborating Mees (1988 and1989)'s conclusions.Mees (1989) and Friel (1994) identified two specimens in alcohol (MZUSP 25155, 2, 71.0-71.5 mm SL) from rio Paranhana, tributary to the rio Sinos (laguna dos Patos system) near Taquara, Rio Grande do Sul, as B. doriae.I

Fig. 6 .
Fig. 6.Map of Rio Grande do Sul, Brazil, and Uruguay showing the distribution of Bunocephalus erondinae.Each square represents one or more collecting localities."T" indicates the type-locality.
description of Pseudobunocephalus, only B. larai and B. doriae occurs in southern Brazil.Bunocephalus larai is distinguished from B. doriae and B. erondinae by the absence of the bony epiphyseal bar formed by the frontals (vs.presence).Bunocephalus doriae was described by