Research Article |
Corresponding author: Fábio Roxo ( roxoff@hotmail.com.br ) Academic editor: Javier Maldonado
© 2016 Fábio Roxo, Gabriel da Costa e Silva, Claudio Oliveira.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Roxo FF, Silva GSC, Oliveira C (2016) Description of a new species of Parotocinclus (Siluriformes, Hypoptopomatinae) from the rio Tapajós basin. ZooKeys 634: 125-136. https://doi.org/10.3897/zookeys.634.9917
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A new species of Parotocinclus is described from three small tributaries of the rio Tapajós basin, Mato Grosso State, Brazil. The new species can be distinguished from its congeners by presenting the following characters: (1) a triangular dark blotch at the anterior base of the dorsal fin, (2) the absence of an adipose fin but presence of one small platelet at typical adipose-fin region, (3) the abdomen completely covered by dermal plates, (4) a pectoral girdle totally exposed, (5) a single series of bicuspid teeth, and (6) the higher number of bicuspid premaxillary and dentary teeth.
Biodiversity, Cascudinhos, freshwater, Neotropical fish, taxonomy
The subfamily Hypoptopomatinae currently includes the tribes Otothyrini, Neoplecostomini, and Hypoptopomatini (sensu
Recently, as a result of molecular studies, the genus Parotocinclus was recognized as non-monophyletic with several species more related to species assigned to other Otothyrini genera, mainly Hisonotus, than to the type species Parotocinclus maculicauda (e.g.
Here, we recognized a new Otothyrini species as a result of collection efforts in the rio Tapajós basin. The new species is described below in the genus Parotocinclus, but we will not be surprised if this new entity is reallocated into a new genus in a close future.
Measurements and counts were taken from the left side. The measurements followed
All from Brazil, Mato Grosso State, rio Tapajós basin.
The new species Parotocinclus dani can be distinguished from all congeners, except P. amazonensis, P. bidentatus, P. britskii, P. eppleyi, P. longirostris, P. polyochrus, and P. variola by one character proposed by
Morphometric and meristic data shown in Table
Holotype | Range | Mean | SD | |
---|---|---|---|---|
SL | 27.3 | 20.7–27.3 | 24.0 | 1.93 |
Percent of SL | ||||
Predorsal length | 48.8 | 45.9–50.1 | 47.7 | 1.24 |
Preanal length | 66.2 | 63.3–67.1 | 65.6 | 1.07 |
Head length | 38.0 | 36.4–46.9 | 39.1 | 2.26 |
Cleithral width | 23.4 | 12.7–26.8 | 22.4 | 4.84 |
Dorsal-fin spine length | 25.8 | 24.0–30.6 | 26.4 | 1.68 |
Base of dorsal fin length | 12.2 | 12.2–15.1 | 14.0 | 0.86 |
Thorax length | 17.5 | 11.6–21.3 | 14.4 | 2.16 |
Pectoral-fin spine length | 28.6 | 27.1–32.8 | 29.8 | 1.47 |
Abdomen length | 22.4 | 19.8–23.5 | 21.4 | 1.19 |
Pelvic-fin spine length | 16.7 | 16.2–21.0 | 17.9 | 1.33 |
Postanal length | 26.7 | 23.6–29.1 | 26.7 | 1.26 |
Caudal peduncle depth | 8.4 | 8.4–9.4 | 8.8 | 0.29 |
Anal width | 13.3 | 12.5–13.8 | 13.2 | 0.44 |
Snout-opercle length | 28.0 | 20.0–30.8 | 26.8 | 4.29 |
Anal-fin spine length | 16.2 | 15.1–18.8 | 17.0 | 1.04 |
Lower caudal spine length | 29.7 | 22.1–30.3 | 27.1 | 2.41 |
Percent of HL | ||||
Head width | 62.3 | 48.0–65.7 | 59.8 | 3.91 |
Head depth | 44.9 | 36.4–49.0 | 43.6 | 2.42 |
Snout length | 53.3 | 43.0–55.6 | 51.6 | 2.69 |
Interorbital width | 40.5 | 31.6–40.8 | 38.4 | 2.15 |
Orbital diameter | 12.5 | 9.7–17.0 | 14.1 | 2.06 |
Suborbital depth | 17.8 | 15.4–20.6 | 18.7 | 1.35 |
Mandibular ramus | 10.5 | 6.9–11.2 | 9.2 | 1.40 |
Meristics | ||||
Lateral plates | 24 | 24–26 | 25 | – |
Premaxillary teeth | 22 | 15–25 | 21 | – |
Dentary teeth | 21 | 15–22 | 21 | – |
Top of head in parieto-supraoccipital region and between orbits convex; superior margin of orbits elevated. Eyes moderately small (9.7–17.0% of HL), and dorsolaterally positioned. Snout pointed and rounded in dorsal view. Nostril small. Body and almost all head plates covered with minute, uniformly sized and evenly distributed odontodes. Absence of tufts of hypertrophied odontodes at posterior medial portion of parieto- supraoccipital or crests on head. Dorsal and ventral anterior margin of snout covered with larger odontodes compared to rest of head. Lips moderately developed and rounded; lower lip far from reaching pectoral girdle. Papillae uniformly distributed on base of dentary and premaxilla, getting smaller distally. Lower lip larger than upper. Maxillary barbel present and poorly developed. Teeth slender and bicuspid; medial cusp larger than lateral cusp. Left premaxillary teeth 15–25 (mode 21). Left dentary teeth 15–22 (mode 21).
Dorsal fin ii,7; its origin slightly posterior to pelvic-fin origin; when depressed reaching beyond vertical line through anal-fin insertion. Tip of branched dorsal-fin rays reaching vertical line slightly posterior of anal-fin origin. Dorsal-fin spinelet V-shaped, laterally extended; dorsal-fin locking mechanism functional. Pectoral fin i,6; tip of longest pectoral-fin ray almost reaching vertical line through center of horizontal pelvic-fin length when depressed. Pectoral axial slit present between pectoral-fin base and lateral process of cleithrum. Lateral margin of pectoral spine possessing odontodes increasing in size posteriorly. Pelvic fin i,5; tip not exceeding anal-fin origin when depressed. Males with flap along dorsal margin of unbranched pelvic-fin ray, absent in females. Anal fin i,5; tip of unbranched anal-fin ray reaching 7th to 9th plate from anal-fin origin. Adipose-fin absent but with small unpaired plates in typical adipose fin region. Caudal fin i,14,i; distal margin forked. Lateral plate series formed by 24–26 (mode 25) plates. Lateral line with one or two unperforated plates in line of pores along mid length of body, terminating in two plates preceding last lateral plate. Abdomen completely covered by dermal plates. Cleithrum partly enclosed by ventral lamina of coracoids.
Background color dark yellowish-brown in dorsal portion of body and yellowish tan in ventral portion. Dorsal surface of head dark brownish, except for striking V-shaped yellowish tan mark from rostral plate passing through nares to orbital margins. Irregular and conspicuous dark brownish longitudinal stripe along lateral line. Four dark brownish bars crossing dorsum, reaching longitudinal stripe on sides of trunk: first below dorsal-fin origin, second at end of dorsal-fin base, third at adipose fin region, and fourth more inconspicuous at end of caudal peduncle. Dorsal, pectoral, and pelvic fins with dark chromatophores, forming irregular sets of bands: five on dorsal and pectoral fins, three to four on pelvic-fin, and four on anal fin. Dorsal-fin with triangular dark blotch at anterior base. Unpaired plates in typical adipose-fin region yellowish tan. Caudal-fin hyaline, except for one black spot at its origin extending to ventral lobe, and two almost inconspicuous bands. Entire body covered with irregularly distributed chromatophores.
Adult males can be distinguished from females by presenting two characters: (1) presence of a papilla at urogenital opening (vs. papilla absent in females), and (2) unbranched pelvic-fin ray supporting a dermal flap on proximal dorsal surface (vs. dermal flap absent in females).
The new species is known from three drainages of rio Tapajós in Mato Grosso State, Brazil (Fig.
The specific name “dani” is in honor of Daniela Fernandes Roxo, FF Roxo’s sister.
Corumbataia cuestae Britski, 1997: LBP 3688, 3, 28.5–29.9 mm SL, municipality of Botucatu, São Paulo State, upper rio Paraná basin.
Curculionichthys insperatus (Britski & Garavello, 2003): LBP 1316, 4 (1 c&s), 23.9–27.7 mm SL, municipality of Botucatu, São Paulo State, rio Tietê basin; LBP 1344, 2, 22.9–24.9 mm SL, municipality of Botucatu, São Paulo State, rio Tietê basin.
Hisonotus bocaiuva Roxo, Silva, Oliveira & Zawadzki, 2013:
Hisonotus bockmanni Carvalho & Datovo, 2012:
Hisonotus francirochai (Ihering, 1928): LBP 5026, 1, 34.6 mm SL, municipality of Rio Claro, São Paulo State, rio Tietê basin.
Hisonotus notatus Eigenmann & Eigenmann, 1889: LBP 3472, 20, 21.0–34.3 mm SL, municipality of Macaé, Rio de Janeiro State, Coastal Drainage.
Lampiella gibbosa (Miranda Ribeiro, 1908): LBP 2652, 8, 27.6–34.2 mm SL, municipality of Campinhos, Paraná State, rio Ribeira de Iguape.
Microlepidogaster dimorpha Martins & Langeani, 2011: LBP 10683, 2, 28.8–35.6 mm SL, municipality of Uberaba, Minas Gerais State, upper rio Paraná basin.
Otothyris travassosi Garavello, Britski & Schaefer, 1998: LBP 1971, 13, 14.0–27.2 mm SL, municipality of Canavieiras, Bahia State, Coastal Drainages.
Otothyropsis marapoama Ribeiro, Carvalho & Melo, 2005: LBP 4698, 6, 23.9–36.3 mm SL, municipality of Marapoama, São Paulo State, rio Tietê basin.
Parotocinclus amazonensis Garavello, 1977:
Parotocinclus cf. bahiensis (Miranda Ribeiro, 1918): LBP 7182, 3, 27.9–35.6 mm SL, municipality of Lençóis, Bahia State, Coastal Drainages.
Parotocinclus longirostris Garavello, 1988:
Parotocinclus maculicauda (Steindachner, 1877): LBP 2869, 15, 20.2–44.7 mm SL, municipality of Miracatu, São Paulo State, rio Ribeira de Iguape basin, LBP 3181, 1, 40.3 mm SL, municipality of Tapiraí, São Paulo State, rio Ribeira do Iguape basin.
Parotocinclus prata (Ribeiro, Melo & Pereira, 2002):
Pseudotothyris obtusa (Miranda Ribeiro, 1911): LBP 898, 17, 23.6–30.9 mm SL, municipality of Cajati, São Paulo State, rio do Queimado.
Schizolecis guntheri (Miranda Ribeiro, 1918): LBP2123, 21, 28.4–36.3 mm SL, municipality of Parati, Rio de Janeiro State, Coastal Drainages, LBP 3546, 77, 20.9–35.8 mm SL, municipality of Ubatuba, São Paulo State, Coastal Drainages.
We wish to thank José L. O. Birindelli, André L. Netto-Ferreira, and Leandro M. Souza for collecting the specimens. We extend our thanks to Cláudio H. Zawadzki for providing the picture of the holotype of P. prata. We take this opportunity to express our appreciation to our sponsors for their respective financial support: FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo, FAPESP proc. no. 2014/05051–5 and 2015/00691–9 to FFR, proc. no. 2012/01622–2 to GSCS), and MCT/CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) (Edital Universal, proc. no. 441347/2014–2 coord. FFR).