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relatively new species Otothyropsis piribebuy, described in 2011, is from the Río Piribebuy, (hence the species name) a tributary to the Río Paraguay basin, Cordillera, Paraguay. It is distinguished from O. marapoama mainly by having a continuous mid-dorsal series of 17-18 lateral plates, a robust levator crest in the hyomandibula, naked areas in the abdomen, an unpigmented circular blotch on the median portion of the lower lobe, and by several features related to sexual dimorphism.

Otothyropsis piribebuy

In the Baench Catfish Atlas no.1 2005 by Hans-Georg Evers and Ingo Seidel this species was undetermined of Genera at the time along with two other species and was given the code number of LG2 (Loricariidae Genus 2). It wasn't until the same year that the new genus was formed with the type species of Otothyropsis marapoama Ribeiro, Carvalho & Melo, 2005 from the Rio Tietê, a river from the upper Rio Paraná basin in southeastern Brazil.

This new taxon belongs to a clade also encompassing the genera Schizolecis, Otothyris and Pseudotothyris. Otothyropsis marapoama is hypothesized to be the sister-group of Pseudotothyris and Otothyris based mainly on the presence of several derived characters of the swim bladder capsule and associated bones. Several paedomorphic characters shared by Pseudotothyris and Otothyris and their significance for the phylogenetic position of the new genus are discussed in the paper by Ribeiro, A.C., M. Carvalho and A.L.A. Melo, 2005.

Otothyropsis piribebuy - feeding on cucumber

Otothyropsis piribebuy - pair with female to left

The first part of the name is from Greek (otos = ear and thyris = window) and is in reference to the Hypoptopomatinae genus Otothyris, to which the new taxon is closely related. The second part is from the Greek (opsis = relating to sight and appearance); hence, resembling a hypoptopomatine fish. Gender: feminine.

There is at the moment (Jan.2022) six species in this genera and including our factsheet of the month the rest are Otothyropsis alicula Lippert, Calegari & Reis, 2014 from the Rio Santo Antônio basin, a tributary to Rio Sapucaí, itself a tributary to the upper Rio Grande, Rio Paraná basin in Brazil, Otothyropsis biamnicus Calegari, Lehmann A. & Reis, 2013 from tributaries to the Rio Iguaçu, in Santa Catarina and Paraná States, and to the Rio Tibagi, Paraná State, both in the Rio Paraná basin, Brazil, O. marapoama Ribeiro, Carvalho & Melo, 2005, the type species from Rio Tietê basin in Brazil, Otothyropsis polyodon Calegari, Lehmann A. & Reis, 2013 from tributaries to the Rio Verde, a tributary to the upper Rio Paraná basin in Mato Grosso do Sul, Brazil and Otothyropsis dialeukos Calegari, Morlis & Reis, 2017 from Arroyo Itá, a tributary to the Embalse de Acaray, upper Río Paraná basin in Paraguay.

Black Oto, LG2

None

Hypoptopomatinae

South America: Río Piribebuy and Río Aguaray, Rio Paraguay basin in Paraguay.

3.0cm (1¼ins)

18-26°c (63-77°f.)

6.0-7.5.

Dorsal spines (total): 2; Dorsal soft rays (total): 7; Anal soft rays: 6; Vertebrae: 26 - 27. Distinguished from other species of the genus by having the following characters: middle series of lateral plates truncated two plates before the caudal fin; inner margin of the pectoral-fin spine smooth, with no serrae; distal margin of the accessory flange of the first ceratobranchial pointed; mid-dorsal lateral series with 17-18 plates and continuous; abdomen usually with unplated areas anteriorly in adults; and males with pre anal length 63.0-66.8% HL and 19-20 middle lateral plates.

Ground colour of dorsal surface of head and body light to median brown, darker laterally on flanks; mostly unpigmented ventrally, except for light brown caudal peduncle and ventral portion of cheek and rostral plates. One sinuous light stripe from snout tip to each nostril, continuing as thin line through upper margin of orbit and compound pterotic. Two inconspicuous lighter stripes on each side of predorsal region and flanking dorsal fin. Fin membranes hyaline with dark brown chromatophores arranged in irregular transverse bands on rays. Caudal fin with four or five transverse bands of dark pigmentation, both on rays and membrane, stronger on base and lower lobe, sometimes imperceptible on upper. Bands on caudal fin sometimes merging to form mostly dark lower lobe. One irregularly shaped, unpigmented area on middle of two or three lowermost branched rays usually conspicuous.

Treat as with all members of the Hypoptopomatinae such as the Otocinclus/Parotocinclus genera with a planted aquarium and an overall cooler temperature. Can be kept with smaller species such as small characins, dwarf cichlids, small labyrinth species and also other small catfish such as Corydoras and the smaller members of the Loracariids.

The eggs are laid on plant leaves and other aquarium furniture. Provide a sponge filter in a small tank if intending to breed as a power filter will suck the fry into it.

Females will get decidely rotund.

Omnivore: algae, tablet foods, flake and small frozen foods.

Hyomandibula: Line of enlarged pores extending posteriorly from the mouth corners.
Median: Middle or towards the midline.
Clade: A group defined by at least one shared derived character or synapomorphy inherited from a common ancestor; a monophyletic higher taxon, a branch on a cladogram.
Taxon: According to the Code, any formal taxonomic unit or category of organisms (species, genus, family, order, class, etc.). Taxa (pl.).
Swim bladder: The air sac that gives fish buoyancy and balance. Acts as sound resonator in some fish.
Anal fin: The median, unpaired, ventrally located fin that lies behind the anus, usually on the posterior half of the fish.
Dorsal: The primary rayed fin(s) on top of the body.
Caudal fin: The tail.
Pectoral fin: The paired fins just behind the head.

Otothyropsis: The first part of the name is from Greek (otos = ear and thyris = window) and is in reference to the Hypoptopomatinae genus Otothyris, to which the new taxon is closely related. The second part is from the Greek (opsis = relating to sight and appearance); hence, resembling a hypoptopomatine fish.
piribebuy: After the river of the same name, a tributary to the Rio Manduvira, Rio Paraguay basin.

Calegari, B.B., P. Lehmann A. and R.E. Reis, 2011. A new species of Otothyropsis (Siluriformes: Loricariidae) from the rio Paraguay basin, Paraguay. Neotrop. Ichthyol. 9(2):253-260.
Froese, R. and D. Pauly. Editors. 2017. FishBase. World Wide Web electronic publication. www.fishbase.org, ( 02/2017 ).
Ribeiro, A.C., M. Carvalho and A.L.A. Melo, 2005. Description and relationships of Otothyropsis marapoama, a new genus and species of Hypoptopomatine catfish (Siluriformes: Loricariidae) from rio Tietê basin, southeastern Brazil. Neotrop. Ichthyol. 3(4):489-498.
Evers, H.-G. & I.Seidel: Mergus, Baensch Catfish Atlas Volume 1, 1st English edn., 2005. Pp.944.

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