A new species of Satanoperca is described from the Rio Araguaia, Rio Tocantins basin, Brazil, and non-native records are available in the upper Rio Paraná basin. It differs from congeneric species by color pattern characters, such as head and flank marks. It is included in the Satanoperca jurupari species group, characterized by the absence of black rounded blotches on the flank, and low meristic values. A description of the ontogeny of melanophore marks of the S. jurupari species group revealed two different types of arrangement on the flank and numerous melanophore marks on the head. A discussion on morphologically diverse assemblages in the S. jurupari species group is also provided.
Diagnosis
Satanoperca setepele differs from S. acuticeps, S. daemon, and S. lilith by the absence of black rounded blotches on the flank (vs. presence: one in S. lilith; two in S. daemon; three in S. acuticeps). It is distinguished from S. leucosticta and S. mapiritensis by the absence of small light blotches on the head (vs. presence). It differs from S. curupira by the presence of two oblique stripes on the lachrymal, one at the superior and another at the inferior margin (vs. 3–7 dark-brown oblique stripes across the lachrymal), dark brown markings absent of cheek and opercular series (vs. irregular pattern of dark-brown stripes present on the cheek and opercular series), by the longitudinal band present and conspicuous in preserved specimens (vs. lateral band absent or inconspicuous in preserved specimens), and by presence of 15–19, mode 18, gill rakers on ceratobranchial 1 (vs. 14–16, mode 15). It differs from S. rhynchitis by the presence of 27–29 scales on E1 series (vs. 26). It differs from S. pappaterra by having the dorsal melanophore patches continuous with flank bars, as conspicuous as, and indistinguishable from them (vs. dorsal melanophore patches continuous with flank bars, but much more conspicuous, and clearly distinguishable from them), and longitudinal band as conspicuous as flank bars along its entire length (vs. longitudinal band much more conspicuous at meeting with flank bars and lateral melanophore patches). From S. jurupari, by the following combination of characters: head always without markings (spots, blotches or stripes) on cheek and opercular series, in both living and preserved specimens (vs. frequently light spots, in living specimens; or dark-brown stripes, in preserved specimens), longitudinal band and flank bars very conspicuous, in preserved specimens (vs. both less conspicuous), longitudinal band as conspicuous as flank bars, in preserved specimens (vs. longitudinal band less conspicuous than flank bars), frequently six flank bars, more visible in juvenile specimens (vs. frequently seven flank bars), and supra-cleithrum smooth, without serrations (vs. frequently with serrations) (Fig. 2). Additionally, S. setepele can be distinguished from the remaining species in the S. jurupari group, except S. pappaterra and S. rhynchitis, by the interorbital and nasal stripes not fragmented into spots and fading with growth (vs. fragmented into spots with growth) (Fig. 3), by the presence, in adults, of double scale series on the caudal-fin inter-radial membranes (vs. all caudal-fin inter-radial scale series single), and a secondary scale series on the caudal-fin inter-radial membranes (i.e., between the branches of a ray; vs. secondary series absent).
Geographical distribution
Satanoperca setepele is known from the Rio Tocantins basin, including its major tributary, the Rio Araguaia, from Rio Cristalino, Cocalinho (in the Rio Araguaia) and Reservatório Serra da Mesa, Niquelândia (in the Rio Tocantins), to the mouth of the Rio Itacaíunas, Marabá. Non-native records are available from the upper Rio Paraná basin (Fig. 8).
Ecological notes and habitat
Stomachs of Satanoperca setepele from the upper Rio Paraná floodplain mainly contained debris (30–60% of frequency), and aquatic and terrestrial insect larvae, mollusks, and higher plants with less frequency (0–30%) (Hahn et al., 1997; 2004). Localities include rivers (rare occurrence), permanent and temporary lagoons (moderate occurrence), and natural canals (Agostinho et al., 1997); and S. setepele is considered sedentary or with restricted displacements (Suzuki et al., 2004).
Etymology
The specific name setepele (literal translation “sete-pele”, in Portuguese; seven skins, in English) refers to a Brazilian designation for demon, representing its shapeshifter capacity. The name is given in allusion to the folklore around Satanoperca [Greek Σατάν (satan, demon); πέρκα (pérkē, Perca)]. A noun in apposition.