A new Aspidoras (Siluriformes: Callichthyidae) from rio Paraguaçu basin, Chapada Diamantina, Bahia, Brazil

Abstract

During a recent ichthyological survey in Chapada Diamantina, Estado da Bahia, Brazil, a new, very distinctive Aspidoras was discovered in tributaries of the upper rio Paraguaçu. The new taxon differs from its congeners mainly in having: a poorly-developed pigmentation pattern, restricted to minute scattered blotches on dorsal region of head and body, but grouped in small, irregular blotches along the lateral body plate junction; four or five caudal vertebra, anterior to compound caudal centrum, with neural and haemal spines placed posteriorly, close to post-zygapophyses; and post-zygapophyses of the precaudal vertebrae without dorsal expansions connected with their respective neural spines. The new species shares with Aspidoras velites dorsolateral body plates not touching their counterparts dorsally, and infraorbital bones with reduced flanges that are restricted to the latero-sensory canal. Both of these are considered reductive character states, probably indicating a paedomorphic condition to both species. The new species is also compared to Aspidoras maculosus, a congener which bears the most similar color pattern and is geographically closest to the new species.<br>Durante um estudo recente sobre a ictiofauna da Chapada Diamantina, foi descoberta uma nova espécie de Aspidoras, bastante distinta morfologicamente de suas congêneres, em afluentes do alto rio Paraguaçu, Estado da Bahia, Brasil. O novo táxon difere das demais espécies de Aspidoras principalmente pela pigmentação pouco desenvolvida, restrita a minúsculas máculas espalhadas na região dorsal da cabeça e corpo, concentradas em pequenas manchas irregulares ao longo da junção das placas laterais; por apresentar as quatro a cinco últimas vértebras caudais anteriores ao centro caudal composto com os espinhos neurais e hemais situados posteriormente junto às pós-zigapófises; e pós-zigapófises das vértebras pré-caudais sem expansões dorsais unidas ao respectivo espinho neural. Além disso, a nova espécie compartilha com Aspidoras velites a condição em que as placas dorso-laterais não contatam suas contrapartes dorsalmente, e os ossos infra-orbitais reduzidos a pouco mais que o canal látero-sensorial, características redutivas, provavelmente indicando um estado de caráter pedomórfico para estas espécies. A nova espécie é ainda comparada a Aspidoras maculosus, congênere mais semelhante no padrão de colorido e também aquela mais próxima geograficamente

Astyanax vermilion and Astyanax burgerai: new characid fishes (Ostariophysi: Characiformes) from Northeastern Bahia, Brazil

“…Coastal northeastern Brazilian rivers are recognized by its high degree of endemism together with the increasing description of new species in the last decade (Lima & Gerhard, 2001;Malabarba et al, 2004;Zanata & Akama, 2004;Britto et al, 2005;Sarmento-Soares et al, 2005;Benine et al, 2007;Birindelli et al, 2007;Zanata & Camelier, 2008). This assertion fits precisely for rivers crossing the area around Ilhéus on Bahia State, as rio Almada, rio Cachoeira and rio do Braço, which holds various putatively endemic species.…”

A new species of Aspidoras (Siluriformes: Callichthyidae) from a small coastal drainage in northeastern Brazil

“…The new species possesses at least two characteristics considered paedomorphic by Britto et al (2002) and Britto et al (2005): dorsolateral body plates in preadipose area not contacting their counterparts, and infraorbital 2 with reduced laminar expansion. The first condition was previously reported for A. velites by Britto et al (2002) and A. psammatides in specimens up to 26.4 mm SL (Britto et al, 2005: 478).…”

“…Almost half of the known species of Aspidoras were described from northeastern Brazil: A. carvalhoi Nijssen & Isbrücker, 1976, from rivers around Guaramiranga, Ceará; A. depinnai Britto, 2000, from the rio Ipojuca basin, Pernambuco; A. maculosus Nijssen & Isbrücker, 1976, from the rio Itapicuru basin, Bahia; A. menezesi Nijssen & Isbrücker, 1976, from the rio Jaguaribe and rio Salgado basins, Ceará; A. psammatides Britto, Lima & Santos, 2005, from the rio Paraguaçu basin, Bahia; A. raimundi (Steindachner, 1907), from rio Parnaíba basin, Maranhão; A. rochai Ihering, 1907, from coastal drainages around Fortaleza, Ceará; A. spilotus Nijssen & Isbrücker, 1976, from the rio Acaraú basin, Ceará; and A. virgulatus Nijssen & Isbrucker, 1980, from coastal streams between Linhares and São Mateus, Espírito Santo. After the analysis of material from the rio da Dona basin, a small coastal drainage that runs through the Atlantic Forest in Bahia State, a new species was revealed and is described herein.…”

Composition and seasonal variation of the ichthyofauna from upper Rio Paraguaçu (Chapada Diamantina, Bahia, Brazil)

“…Recently, Higuchi et al (1990);Pinna (1992); , and Zanata and Akama (2004), Britto et al (2005), described new genera and species of Douradidae and Characidae, and a new subfamily of Trichomycteridae in the Paraguaçu basin. In this work, 10 new species were determined (including the recently described Hyphessobrycon negodagua, Aspidoras psammatides and Myxiops aphos).…”

“…Aspidoras psammatides (Britto, Lima and Santos, 2005) Corydoras cf. Geophagus brasiliensis (Quoy and Gaimard, 1824)…”