Parotocinclus fluminense, Roxo, Fábio F., Melo, Bruno F., Silva, Gabriel S. C. & Oliveira, Claudio, 2017

Roxo, Fábio F., Melo, Bruno F., Silva, Gabriel S. C. & Oliveira, Claudio, 2017, New species of Parotocinclus (Siluriformes: Loricariidae) from coastal drainages of Rio de Janeiro, southeastern Brazil, Zootaxa 4232 (2), pp. 260-270: 261-265

publication ID

https://doi.org/10.11646/zootaxa.4232.2.9

publication LSID

lsid:zoobank.org:pub:29CDBE09-F1C0-4BC1-BC57-6BA208B4FD8F

persistent identifier

http://treatment.plazi.org/id/03F787DB-594D-FFC0-C49B-B1D4A017FCEC

treatment provided by

Plazi

scientific name

Parotocinclus fluminense
status

new species

Parotocinclus fluminense  , new species

( Fig. 1View FIGURE 1, Table 1)

Holotype. MZUSP 120989View Materials, male, 27.7 mm SL, Brazil, Rio de Janeiro, municipality of Casemiro de Abreu, rio Branco, tributary of rio São João , coastal drainage, 22°27’04”S 42°05’04”WGoogleMaps  , May 2016, D. Freitas-Souza, & F.P. Lima.

Paratypes. All from Rio de Janeiro, Brazil (124 total paratypes): ANSP 200535, 4, 19.5–25.0 mm SL, municipality of Silva Jardim , rio Ouro, rio São João, 22°34’22”S 42°28’17”W, May 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . AUM 67842, 4, 22.2–31.1 mm SL, municipality of Silva Jardim , rio Ouro, rio São João, 22°34’22”S 42°28’17”W, May 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 18474View Materials, 16, 25.2–35.5 mm SL, municipality of Silva Jardim , córrego Bananeiras, tributary of rio São João, 22°28’51”S 42°23’39”W, Nov. 2013, R. Devidé, G.J.C. Silva, P.C. Scacchetti & R. UtsunomiaGoogleMaps  . LBP 21948View Materials, 7, 21.9–27.0 mm SL, 2 c&s, 25.3–25.4 mm SL, same data as holotypeGoogleMaps  . LBP 21999View Materials, 8, 16.7–26.2 mm SL, 2 c&s, 23.1–30.2 mm SL, municipality of Silva Jardim , rio Maratuã, rio São João, 22°31’40”S 42°21’25”W, May 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22037View Materials, 9, 16.3–31.0 mm SL, 2 c&s, 27.1–32.1 mm SL, municipality of Silva Jardim , rio Ouro, rio São João, 22°34’22”S 42°28’17”W, May 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22061View Materials, 3, 23.1–30.3 mm SL, municipality of Varginha , rio Capivari, rio São João, 22°38’23”S 42°28’16”W, May 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22080View Materials, 7, 21.0– 29.1 mm SL, municipality of Rio Bonito , rio Bacaxá, rio São João, 22°41’34”S 42°33’12”W, May 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22279View Materials, 18, 21.9–35.8 mm SL, municipality of Silva Jardim , rio São João, 22°32’40”S 42°27’52”W, Aug. 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22280View Materials, 18, 25.3–33.3 mm SL, municipality of Silva Jardim , rio Bacaxá, rio São João, 22°41’34”S 42°33’12”W, Aug. 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22281View Materials, 4, 18.9– 26.6 mm SL, municipality of Casemiro de Abreu , rio Ibiabas, tributary of rio São João, 22°28’38”S 42°14’48”W, Aug. 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22282View Materials, 1, 26.4 mm SL, municipality of Casemiro de Abreu , rio Lontras, tributary of rio São João, 22°28’31”S 42°09’01”W, Aug. 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22283View Materials, 6, 22.1–34.1 mm SL, municipality of Silva Jardim , rio Maratuã, tributary of rio São João, 22°31’40”S 42°21’25”W, Aug. 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22284View Materials, 1, 23.4 mm SL, municipality of Silva Jardim , rio Imbaé, tributary of rio São João, 22°38’13”S 42°27’35”W, Aug. 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . LBP 22285View Materials, 1, 22.9 mm SL, municipality of Silva Jardim , rio Aldeia, tributary of rio São João, 22°29’17”S 42°16’14”W, Aug. 2016, D. Freitas-Souza & F.P. LimaGoogleMaps  . MCP 50865, 4, 24.7–31.9 mm SL, municipality of Rio Bonito , rio Bacaxá, tributary of rio São João, coastal drainage, 22°41’34”S 42°33’12”W, May 2016, D. Freitas- Souza & F.P. Lima. MZUSP 120990, 3, 21.4–26.2 mm SL, same data as holotypeGoogleMaps  . NUP 18791View Materials, 4, 24.9–33.1 mm SL, municipality of Rio Bonito , rio Bacaxá, rio São João, 22°41’34”S 42°33’12”W, May 2016, D. Freitas-Souza & F.P. Lima.GoogleMaps 

Diagnosis. Parotocinclus fluminense  can be distinguished from all congeners, except P. amazonensis Garavello, 1977  , P. bidentatus  , P. britskii  , P. dani Roxo, Silva & Oliveira, 2016  , P. eppleyi  , P. longirostris Garavello, 1988  , P. polyochrus Schaefer, 1988  and P. variola Lehmann A., Schvambach & Reis, 2015  by the presence of a triangular patch of dark pigmentation at the anterior portion of the dorsal-fin base (vs. absence of a triangular dark blotch). Additionally, P. fluminense  differs from P. bidentatus  , P. dani  , P. halbothi Lehmann A., Lazzarotto & Reis, 2014  , P. muriaensis  , P. seridoensis Ramos, Barros-Neto, Britski & Lima, 2013  and P. spilurus ( Fowler, 1941)  by the presence of a fully developed adipose fin (vs. absent or poorly developed adipose fin); it differs from P. cearensis Garavello, 1977  , P. cesarpintoi  , P. jumbo Britski & Garavello, 2002  , P. prata Ribeiro, Melo & Pereira, 2002  , P. robustus Lehmann A. & Reis, 2012  , P. spilosoma ( Fowler, 1941)  and P. spilurus  by possessing a total exposure of the ventral surface of the pectoral girdle ( Fig. 2View FIGURE 2 a) (vs. ventral exposure restricted to a small lateral portion of the girdle and covered medially by a skin, Fig. 2View FIGURE 2 b); it differs from P. amazonensis  , P. arandai  , P. britskii  , P. collinsae Schmidt & Ferraris, 1985  , P. eppleyi  , P. halbothi  , P. longirostris  , P. polyochrus  , P. prata  , P. robustus  , P. spilurus  , P. seridoensis  and P. variola  , by the distinctive pigmentation pattern of the caudal fin, which has a hyaline background with a large black stain covering the anterior portion of the caudal fin, tapering irregularly through the distal portion of the ventral lobe that results in a hyaline rounded area, and a small patch of dark pigmentation on distal portions of the dorsal lobe (vs. absence of such pigmentation pattern).

Description. Morphometric data presented in Table 1. Body relatively small. Dorsal profile slightly convex from snout tip to dorsal-fin origin; straight from this point to end of caudal peduncle. Ventral profile straight to slightly convex from tip of snout to anal-fin insertion, then slightly concave to lower caudal-fin spine insertion. Maximum body depth at dorsal-fin origin. In dorsal view, largest body width at cleithrum progressively narrowing towards snout tip and caudal peduncle. Cross-section of body between pectoral- and pelvic-fin insertions rounded dorsally and laterally, ventrally flat. Cross-section of caudal peduncle ellipsoid.

Supraorbital elevated. Orbital diameter moderately small with orbits positioned dorsolaterally. Snout moderately long and rounded in dorsal view. Nares small, apparently slightly larger in males than in females. Odontodes evenly distributed covering body and head plates. Odontodes in snout margin larger than those of head. Absence of tufts of hypertrophied odontodes at posterior medial portion of parieto-supraoccipital and crests on head. Lips moderately developed and rounded; lower lip not reaching pectoral girdle. Lower lip twice as large as upper lip. Papillae uniformly distributed on base of lips, decreasing in size distally. Maxillary barbel present and poorly developed, one quarter lower lip length. Teeth slender and bicuspid; medial cusp larger than lateral cusps. Second series of unicuspid teeth present in juveniles (specimens smaller than 23.5 mm SL). Left premaxillary bicuspid teeth 18¯31 (mode 26). Left dentary bicuspid teeth 17¯27 (mode 25).

Dorsal-fin rays ii,7; its origin posterior to pelvic-fin origin; dorsal-fin unbranched ray slightly convex, with its distal portion surpassing vertical line through last anal-fin branched ray insertion. Dorsal-fin spinelet laterally extended, V -shaped, and dorsal-fin locking mechanism functional. Pectoral-fin rays i,6; tip of longest pectoral-fin ray (first branched ray) reaching beyond vertical line through center of pelvic-fin length when adpressed. Pectoral axial slit present between pectoral-fin base and lateral process of cleithrum. Lateral and ventral margins of pectoral spine possessing odontodes increasing in size posteriorly. Pelvic-fin rays i,5; tip exceeding anal-fin unbranched ray insertion when adpressed; ventral margin possessing odontodes increasing in size posteriorly. Males with flap along dorsal margin of unbranched pelvic-fin ray, absent in females. Anal-fin rays i,5; tip of unbranched anal-fin ray reaching seventh to eighth plate from anal-fin origin. Adipose fin present and well developed with membrane in ventral portion of the spine. Adipose fin preceded by one median, azygous plate. Caudal-fin rays i,14,i; distal margin forked.

Lateral plate series formed by 21¯26 (mode 24) plates. Lateral line complete, without gaps along perforated plates, terminating in zero or two unperforated plates. Abdomen partially covered by dermal plates; naked areas between median and lateral plate series. Cleithrum partially enclosed by ventral lamina of coracoid.

Color in alcohol. Ground coloration of dorsal surface of head and body dark and gray, same color pattern in adults and juveniles. Ventral surface light brown to yellow. All body and fins scattered by dark chromatophores, more so on dorsal and lateral portions of body. Orbital margin slightly brighter dorsally. Lateral surface of body covered by a wide black strip extending along lateral line, from snout tip to anterior margin of caudal fin. Dorsal portion of snout delineated by two hyaline stripes from its tip to nares. Four transverse light bands along dorsal surface of body, one located at caudal-fin origin, one posteriorly to adipose fin, one posteriorly to dorsal-fin origin, and one covering a large area around dorsal-fin origin. Dorsal, pectoral, pelvic, and anal fins with irregular series of dark spots on rays, sometimes forming stripes, more so on pectoral-fin rays. Anterior portion of the dorsal-fin membrane with a triangular patch of dark pigmentation. Anteroventral portion of the caudal fin with a distinctive dark mark extending irregularly through distal portions of the ventral lobe, with hyaline rounded area. Small patch of dark pigmentation on distal portions of dorsal-fin lobe ( Fig. 1View FIGURE 1).

Sexual dimorphism. Males have papilla at urogenital opening (vs. papilla absent in females) and unbranched pelvic-fin ray supporting dermal flap along ventral surface (vs. dermal flap absent in females). Nares apparently larger in males.

Distribution. Parotocinclus fluminense  are so far known from nine small tributaries of rio São João (rio Aldeia, rio Bacaxá, rio Branco, rio Capivari, rio Ibiabas, rio Imbaé, rio Lontras, rio Maratuã, and rio Ouro) a coastal river flowing directly to Atlantic Ocean, state of Rio de Janeiro, southeastern of Brazil ( Fig. 3View FIGURE 3).

Habitat. Parotocinclus fluminense  was found associated with marginal submerged vegetation that covers the bottom and the border of the headwaters in moderate flowing sections of the rivers. The region has suffered high anthropic influence, such as cattle and agriculture. Penetration of light is intense due marginal erosion ( Fig. 4View FIGURE 4).

Etymology. From Latin flumine = river; and ense = natural, in allusion to the Baixada Fluminense  , relative to the area surrounding the city of Rio de Janeiro in which Parotocinclus fluminense  inhabits and, consequently, in honor to the population from the state of Rio de Janeiro, popularly named fluminense  . A noun in apposition.

TABLE 1. Morphometric data of Parotocinclus fluminense (holotype and 21 paratypes). SD = standard deviation.

  Holotype     SD
    23.5‾30.8    
    44.6‾49.8    
    60.2‾66.0    
    33.1‾37.9    
    22.8‾25.3    
    23.4‾28.0    
    13.6‾16.8    
    23.9‾29.8    
    20.5‾23.8    
    16.6‾22.2    
    16.0‾19.3    
    28.3‾35.8    
    27.2‾32.5    
    13.5‾16.9    
    38.7‾45.2    
    50.5‾56.8    
    35.6‾38.6    
    14.2‾18.4    
MZUSP

Museu de Zoologia da Universidade de Sao Paulo

ANSP

Academy of Natural Sciences of Philadelphia

AUM

Auburn University Museum of Natural History

MCP

Pontificia Universidade Catolica do Rio Grande do Sul