| Family: |
Heptapteridae (Three-barbeled catfishes) |
| Max. size: |
15.75 cm SL (male/unsexed) |
| Environment: |
demersal; freshwater |
| Distribution: |
South America: known only from Arroyo Cuña-Pirú, Río Paraná basin in Argentina. |
| Diagnosis: |
Dorsal soft rays (total): 7-8; Anal soft rays: 16-18. Presence of a distinct and large ovoid area in the supraorbital laterosensory canal between the frontal and sphenotic delimited by the apparently slender dorsal walls of these bones and with foramen for a laterosensory branch. Differs further from other species of Rhamdella by the following combination of characters: barbel tip reaching from the base of pectoral-fin ray in a specimen measuring 8.80 cm SL, to the posterior portion of opercular region, not surpassing the branchial slit, in a 15.75 cm SL specimen; horizontal eye diameter 20.6-23.9% of HL; interorbital distance 17.9-20.7% of HL; snout profile slightly convex but almost straight; branchiostegal rays seven, branchiostegal membranes not reaching the basal part of the first pectoral-fin ray in most specimens; interdorsal length 7.6-11.3% of SL; adipose-fin base length 36.0-41.6% of SL; anal-fin base length 16.6-22.0% of SL; anal-fin rays 16-18, commonly 17; and length of ventral caudal-fin lobe is 55.8-65.5% of length of dorsal lobe in males; snout length 37.9-43.2% of HL; pelvic fin length 13.3-16.9% of SL; a dense concentration of long and slender papillae on the lateral body surface in the pectoral and abdominal regions, most conspicuous near the lateral line, resulting in a hairy aspect; and by the presence of a distinct narrow dark mid lateral stripe (Ref. 75872).
Description: Dorsal fin with 1 long unbranched and 6 or 7 branched rays; Anal fin with 16, 17, or 18 rays, including 10 or 11 branched rays (vi,10, v,11, vii,10, vi,11, or viii,10); Pectoral fin with 1 unbranched and 8, 9, or 10 branched rays; Pelvic fin with 6 rays (Ref. 75872). |
| Biology: |
Occurs over rocky bottoms in a clear water stream, approximately 0.5 - 1 m deep, with pools around 3 m deep, running through a densely forested area (Ref. 75872). Tends to be gregarious as individuals were observed in dense group under large stones (Ref. 75872). |
| IUCN Red List Status: |
Vulnerable (VU); Date assessed: 24 November 2020 (B1ab(iii)) Ref. (130435)
|
| Threat to humans: |
harmless |
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