Aspidoras brunneus Nijssen & Isbrücker, 1976

Tencatt, Luiz Fernando Caserta, Britto, Marcelo R., Isbrücker, Isaäc Jan Hendrik & Pavanelli, Carla Simone, 2022, Taxonomy of the armored catfish genus Aspidoras (Siluriformes: Callichthyidae) revisited, with the description of a new species, Neotropical Ichthyology (e 220040) 20 (3), pp. 1-159 : 49-51

Aspidoras brunneus Nijssen & Isbrücker, 1976

( Figs. 25–26 )

Aspidoras brunneus Nijssen & Isbrücker, 1976:116 (original description; type locality: Serra do Roncador , km 125 of the road Chavantina-Casximba [sic, = Xavantina-Cachimbo ], Mato Grosso State, Brazil). — Britto, 2000:1054 (listed as comparative material). — Lima, Britto, 2001:1015 (listed as comparative material). — Reis , 2003:292 (listed). — Ferraris , 2007:109 (listed). — Leão et al., 2015:578 (morphological comparison). — Oliveira et al., 2017:e160118[7] (morphological comparison).

Diagnosis. Aspidoras brunneus can be distinguished from all of its congeners by having a wide, longitudinal, conspicuous dark brown stripe along dorsal portion of flank (vs. absence of such stripe). Additionally, it can be distinguished from A. aldebaran , A. belenos , A. depinnai , A. fuscoguttatus , A. maculosus , A. poecilus , A. psammatides , A. raimundi , and A. rochai by having nuchal plate entirely covered by a thick layer of skin (vs. nuchal plate with at least posterior portion exposed).

Conservation status. Aspidoras brunneus is currently known only from its type locality, which is dubious regarding drainage (see Remarks below), and the sole available material is composed only by its type series. Two attempts to capture this species in the Serra do Roncador region led by LFCT in 2016 (September and November) were unsuccessful. Additionally, a visit to the Universidade Federal do Mato Grosso in Barra do Garças/Pontal do Araguaia, where the ichthyologist Dilermando Lima holds a small fish collection from the Serra do Roncador area, also did not reveal any specimens of A. brunneus . Based on the material gathered for our study, the only Aspidoras species recently found in the region are A. albater and A. poecilus . Considering that this species is known only from its unclear type locality, and the fact that the region presents severe signs of anthropic impact, especially for agricultural and cattle raising purposes, it is not possible to adequately assess the risk of extinction of the population. According to the International Union for Conservation of Nature (IUCN) categories and criteria (IUCN Standards and Petitions Subcommittee, 2019), Aspidoras brunneus can be classified as Data Deficient (DD).

Remarks. Aspidoras brunneus was described based on six specimens collected in “ Mato Grosso, Serra do Roncador, km 125 of the road Chavantina-Casximba” (see Nijssen, Isbrücker, 1976:116). The road mentioned by the authors must be the Xavantina-Cachimbo road, depicted by Lowe-McConnell (1991:65, fig. 1), which seems to be, at least partially, equivalent to the current BR-158 road. Streams of the Serra do Roncador region is drain into the rivers Araguaia and Xingu basins (see Lowe-McConnell, 1991). Following both BR-158 and Xavantina-Cachimbo roads, it is possible to see tributaries from both basins crossing or close to them at several points. Therefore, even with the kilometer reference, it is not possible to confidently state the basin in which A. brunneus was captured, though some studies explicitly pointed to it as being from the rio Araguaia basin (Wosiacki et al., 2014:314) or the rio Xingu basin ( Britto, 2000:1048; Leão et al., 2015:583). Contrary to its unclear type locality, A. brunneus is one of the most peculiar species of the genus, being promptly diagnosed from all its congeners by the presence of a wide, longitudinal conspicuous dark brown stripe along dorsal portion of flank ( Figs. 25 , 26 ). However, even with the relatively large number of specimens examined herein from both the Araguaia and Xingu basins in the Serra do Roncador region, no specimen with the unusual color pattern of A. brunneus was observed, and only A. albater and A. poecilus were recorded from there. Considering that the only available material of this species is restricted to the six poorly preserved type specimens, a redescription of A. brunneus is not provided herein.

Material examined. Same as listed by Nijssen, Isbrücker (1976:116).

Figures

FIGURE 25 | Aspidoras brunneus, holotype, ZMA 113588, 20.9 mm SL, Serra do Roncador, km 125 of the road Xavantina-Cachimbo, Mato Grosso, Brazil. Dorsal (top), lateral (middle) and ventral (bottom) views. Photos by Mark Allen.

FIGURE 26 | Aspidoras brunneus, paratype, USNM 213569, 17.9 mm SL, Serra do Roncador, km 125 of the road Xavantina-Cachimbo, Mato Grosso, Brazil. Photo by Sandra Raredon.