Aspidoras marianae

description

Description. Small species, largest specimen 28.5 mm SL. Morphometric data presented in Table 1. Head slightly compressed, with convex dorsal profile. Snout rounded in dorsal view. Dorsal profile of body convex from snout dorsal-fin base; slightly concave from last dorsal-fin ray to caudal peduncle. Ventral profile of body slightly convex from snout to pelvic girdle region; straight from this point to anal-fin origin; markedly concave from first anal-fin ray to caudal-fin base. Body roughly elliptical in cross-section at pectoral girdle, gradually more compressed toward caudal fin. Eye rounded, dorsolaterally on head. Orbit delimited dorsally by frontal and sphenotic, anteriorly by lateral ethmoid, and ventral and posteriorly by infraorbitals. Anterior and posterior nares very close, separated by thin skin flap. Anterior naris tubular. Small papillae on surface of snout. Mouth small and subterminal. One pair of maxillary barbels and two pairs of mental barbels. Maxillary barbel not reaching limit of gill opening ventrally. Maxillary barbel slightly longer than outer mental barbel. Inner mental barbel fleshy, nearly one-fourth of outer mental barbel length. Minute rounded papillae o

A new species of Aspidoras Ihering (Siluriformes: Callichthyidae: Corydoradinae) from the Rio Xingu Basin, Pará, Brazil

diagnosis

Diagnosis. Aspidoras marianae differs from its congeners by the presence of minute odontode-bearing platelets scattered over surface of snout region (Fig. 2; vs. absence). The new species can be distinguished from its congeners, except A. taurus, by the presence of infraorbital 1 and 2 covered by thick skin and not visible externally (vs. externally visible); and from A. taurus by the possession of minute platelets between parieto-supraoccipital process and nuchal plate (vs. absence). Additionally, the new species can be distinguished from Aspidoras microgalaeus and A. belenos by the presence of three nasal pores (vs. two); from A. velites by presenting ventral laminar expansion of the first infraorbital conspicuously expanded (Fig. 3; vs. very reduced, almost absent in some specimens); by the number of dorsal-fin rays, II, 7, i (vs. II, 7 – II, 8); the reduced number of ventrolateral body plates, 22 – 23 (vs. 24 – 26); the greater depth of body, 28.0 – 31.0 % SL (vs. 15.0 – 20.3 %); the greater maximum cleithral width, 24.1 – 28.5 % SL (vs. 12.5 – 17.1 %); the greater head depth, 68.2 – 83.0 % HL (vs. 53.2 – 64.6 %); the greater least interorbital distance, 49.9 – 58.6 % HL (vs. 3

A new species of Aspidoras Ihering (Siluriformes: Callichthyidae: Corydoradinae) from the Rio Xingu Basin, Pará, Brazil

distribution

Distribution. Known only from its type locality, an unnamed stream tributary of the Rio Curuá, itself a tributary of the Rio Iriri, in the Rio Xingu basin (Fig. 7). Habitat notes. Aspidoras marianae was only collected in a slow-flowing stream with clear water and a sandy bottom with mud, leaf litter, submerged logs, and some aquatic macrophytes (Fig. 8).

A new species of Aspidoras Ihering (Siluriformes: Callichthyidae: Corydoradinae) from the Rio Xingu Basin, Pará, Brazil

etymology

Etymology. The specific epithet marianae is a reference to Mariana P. Wosiacki, daughter of the third author. A genitive noun.

A new species of Aspidoras Ihering (Siluriformes: Callichthyidae: Corydoradinae) from the Rio Xingu Basin, Pará, Brazil