| Trichomycteridae (Pencil or parasitic catfishes), subfamily: Trichomycterinae |
| 3.02 cm SL (male/unsexed) |
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demersal; freshwater |
| South America: Río Huerta de Huachi in Argentina. |
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Dorsal soft rays (total): 11-13; Vertebrae: 37-39. Distinguished from Silvinichthys bortayro by the following characters: triangular shape of the head from a dorsal view (vs. more rectangular); 8-11 (vs. 2-4) opercular odontodes and 21-28 (vs. 9-12) interopercle odontodes apparent in cleared and stained specimens; 11-13 dorsal-fin rays (vs. 9); caudal-peduncle depth 8.8-10.9% SL (vs. 8.0-8.3% SL); snout length 43.3-61.9% HL (vs. 38.2-40.5% HL); head with broadly separated, dark, marmorated bands of pigmentation and body with a more concentrated, but still diffuse, patch of darker pigmentation overlying the dorsal surface of the cranium and the dorsal portions of the pectoral girdle (vs. lacks the dark marmorated pigmentation in larger individuals); absence of dark midlateral stripe on the caudal peduncle at all sizes (vs. presence of a dark midlateral stripe in mid-sized specimens). Differs from S. gualcamayo by the caudal peduncle length 19.3-21.5 % SL (vs. 22.0-23.9% ) and the insertion point of the first proximal dorsal-fin pterygiophore is posterior to the neural spine of vertebra 21 (vs. 22); from S. leoncitensis by having 37-39 vertebrae (vs. 40), 16-18 ribs on each side (vs. 20); 6-7 pectoral-fin rays (vs. 8), body depth 12.6-16.5 % SL (vs. 8.4-12.2% SL), caudal-peduncle depth 8.8-10.9% SL (vs. 6.6-8.6% SL), and the insertion point of the first proximal dorsal-fin pterygiophore posterior to the neural spine of vertebra 21 (vs. 23); and from S. mendozensis by the absence of pelvic fin and pelvic-fin girdle (vs. presence) and 21-28 (vs. 30-42) interopercle odontodes apparent in cleared and stained specimens (Ref. 95056).
Description: Dorsal fin with 3-5 unbranched rays and 7-8 branched rays; anal fin with 2-4 unbranched rays and 6 or 7 branched rays (Ref. 95056). |
| The type locality is a clear water stream with depth of 0.06-0.30 m and width of 1.5-2.0 m over a rock and cobble bottom, water temperature of 19.7°C and surrounded by limited riparian vegetation. Nocturnally active with individuals observed swimming during the night and hiding among rocks on the stream bed during the day. Stomach contents of 2 specimens consisted of dipteran larvae (Chironomidae) and sand, suggesting that this species feeds on autochthonous benthic macroinvertebrates. Spawns before April since observations during that month in 2009 revealed that its population at the sampling site contained larger numbers of juveniles than adults (Ref. 95056). |
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Not Evaluated (N.E.) Ref. (130435)
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| harmless |
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