Trichomycterus maracaya Bockmann & Sazima, 2004
Margay pencil catfish
photo by Sazima, I.

Family:  Trichomycteridae (Pencil or parasitic catfishes), subfamily: Trichomycterinae
Max. size:  5.1 cm SL (male/unsexed)
Environment:  demersal; freshwater; depth range - 1 m
Distribution:  South America: Rio Pardo drainage, upper Rio ParanĂ¡, southeastern Brazil.
Diagnosis:  Vertebrae: 42-42. Belongs to the Trichomycterus brasiliensis species-complex based on the possession of the following apomorphic characters unique in Trichomycterus: four longitudinal rows of well-defined blotches formed by very dense concentration of dark chromatophores in the deeper layer of skin; and pectoral fin with I+5-6 rays. Members of this putative clade, except T. iheringi, may be further distinguished from other species of Trichomycterus in having the bases of the pelvic fins very close to each other, sometimes in contact. Differs from the remaining species of Trichomycterus (except T. brasiliensis and T. potschi) in retaining the primordial epiphyseal cartilaginous bar separating the anterior and posterior cranial fontanels even in larger individuals. Distinguished further from other species of the T. brasiliensis species-complex and from all congeners in the following putative autapomorphies: row of blotches on lateral surface not forming a lateral stripe in any stage during ontogeny; and superficial layer of pigmentation of juveniles and larger, presumably adult, specimens formed by scattered chromatophores (Ref. 51380). Description: Dorsal-fin rays ii+II+7, rarely iii+III+7. Anal-fin rays ii+II+5, iii+II+5. Pectoral-fin rays I+6, rarely I+7. Pelvic-fin rays I+4 (Ref. 51380).
Biology:  A rheophilic species which dwells on limonite rocky bottom streamlet with pebbles and sand, and pools with muddy bottom and accumulated plant debris. Crepuscular and nocturnal, it forages on the bottom and picks mostly benthic prey. Feeds on immature aquatic insects (ephemeropterans, trichopterans, and plecopterans) with larger individuals preying on small tadpoles (Ref. 51380).
IUCN Red List Status: Least Concern (LC); Date assessed: 07 November 2018 Ref. (130435)
Threat to humans:  harmless


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