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A new callichthyid catfish, Corydoras gracilis, from Brazil (Pisces, Siluriformes, Callichthyidae).
A new long‐snouted Corydoras species is described from two tributaries of the río Manuripe and a tributary of the río Madre de Dios, rio Madeira basin, Peru. Corydoras fulleri can be distinguished from its congeners by having the following features: (a) branch of the temporal sensory canal at sphenotic, which gives rise to the supraorbital canal, with two pores; (b) upper tooth plate of branchial arch with three series of teeth; (c) area at the corner of the mouth, ventral to the maxillary barbel, with a small fleshy flap; (d) two moderate‐sized dark‐brown or black blotches on caudal‐fin base, one on its lateral portion and another one on its dorsal portion, blotches variably diffuse and/or fused with each other; (e) absence of a dark‐brown or black stripe transversally crossing the orbit; (f) a longitudinal dark‐brown or black stripe on the postdorsal region of flank midline, variably fused with the lateral peduncular blotch, some specimens with slender, longitudinally elongated, dark‐brown or black blotch on flank midline, forming a dash‐like marking, stripe or dash‐like blotch diffuse in some specimens; and (g) region around dorsal‐fin origin generally lacking dark brown or black blotch, or displaying diffuse blotch.
A new Corydoras is described from the Blanco and Ucayali river basins in Peru. The new species can be distinguished from its congeners by having the following features: (I) posterior margin of dorsal-fin spine with laminar serrations directed towards the origin of the spine; (II) a long, wide, arched, and continuous black stripe, which runs parallel to the dorsal profile of the body, extending at least from the region below anterior origin of dorsal fin to the anterior half of the ventral caudal-fin lobe; (III) a black stripe transversally crossing the eye, forming the typical mask-like blotch; mask clearly not fused to arched stripe in most specimens; some specimens with mask separated from arched stripe by a thin line around the suture between neurocranium (in the region composed by the posteroventral margin of parieto-supraoccipital plus the posterodorsal margin of the compound pterotic) and first dorsolateral body plate; (IV) posterior margin of pectoral-fin spine with laminar serrations directed towards the origin of the spine; (V) pointed snout, presenting a long mesethmoid, with anterior tip larger than 50% of the entire length of the bone; and (V) ventral surface of trunk covered by small, non-coalescent platelets. A discussion on the possible positive adaptive value of the arc-striped color pattern is also provided.
Two new species of Corydoras are described from the rio Madeira basin, Brazil. The intermediate long-snouted new species can be distinguished from its congeners by presenting the following combination of features: posterior margin of dorsal-fin spine with laminar serrations directed towards the origin of the spine; presence of two longitudinal black stripes on flanks; anterior portion of dorsal fin with sparse black chromatophores, not forming any conspicuous pattern; absence of a conspicuous black marbled coloration pattern on head; black spots on caudal fin, some spots arranged, forming transversal bars; and brownish dorsal-fin spine. The short-snouted new species can be distinguished from its congeners by the following combination of features: short mesethmoid; posterior laminar expansion of infraorbital 2 very reduced, not in contact with compound pterotic; two or three longitudinal black stripes on flanks; absence of an oblique or vertical black blotch across the eye; anterior portion of dorsal fin with sparse black chromatophores, not forming any conspicuous pattern; and ventral surface of trunk naked or covered by sparse platelets.
Corydoras guapore was described from the rio Guaporé, Rondônia State, Brazil, based only in three specimens, two of them merely examined alive in an aquarium and apparently not preserved posteriorly. The current location of these two paratypes is uncertain. In the original description, no standard diagnosis was presented and the descriptive information available is scarce and based only in external morphology. Thus, the aim of this study is to provide a redescription of C. guapore based in several topotypes. Corydoras guapore can be distinguished from its congeners by the presence of a short mesethmoid, with the anterior tip poorly developed; posterior margin of pectoral spine with conical serrations directed towards the origin of the spine; and by the lateral portion of caudal peduncle almost entirely blackened. Information about C. guapore ecology and conservation status are also provided. Corydoras guapore foi descrita do rio Guaporé, estado de Rondônia, Brasil, com base em somente três exemplares, sendo dois deles apenas examinados vivos em um aquário e aparentemente não preservados posteriormente. A atual localização desses dois parátipos é incerta. Na descrição original, uma diagnose padrão não foi apresentada e as informações descritivas disponíveis são escassas e baseadas apenas em morfologia externa. Dessa forma, o objetivo desse estudo é fornecer uma redescrição de C. guapore baseada em vários topótipos. Corydoras guapore pode ser distinguida de suas congêneres pela presença de mesetmóide curto, com a extremidade anterior pouco desenvolvida, margem posterior do acúleo peitoral com serrilhas cônicas voltadas em direção à origem do acúleo, e pela porção lateral do pedúnculo caudal quase totalmente enegrecida. Informações sobre a ecologia e status de conservação de C. guapore também são fornecidas.
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