Neoplecostomus corumba , Zawadzki, Cláudio Henrique, Pavanelli, Carla Simone & Langeani, Francisco, 2008

Zawadzki, Cláudio Henrique, Pavanelli, Carla Simone & Langeani, Francisco, 2008, Neoplecostomus (Teleostei: Loricariidae) from the upper Rio Paraná basin, Brazil, with description of three new species, Zootaxa 1757, pp. 31-48: 32-36

publication ID

10.5281/zenodo.181836

persistent identifier

http://treatment.plazi.org/id/127687E2-FF83-FFFF-BFCA-FB53FB26F8D0

treatment provided by

Plazi

scientific name

Neoplecostomus corumba
status

n. sp.

Neoplecostomus corumba  , n. sp.

Figure 2 View Figure ; Table 1

Neoplecostomus  sp.: Zawadzki et al., 2004: 574 (photo; Goiás, Rio Corumbá  , tributary to Rio Paranaíba; comparison to N. paranensis  ; allozymes).

Neoplecostomus  sp.—“cascudinho”: Pavanelli et al., 2007: 61 (citation; Goiás, Rio Corumbá  , tributary to Rio Paranaíba).

Holotype. DZSJRP 6713 [male], 78.3 mm SL, Goiás State, Corumbaíba, Córrego Gameleira, affluent of Rio Corumbá  , Rio Paranaíba basin, 17 o 59 ’S / 48 o 29 ’W, 17 Sep 1996, Nupélia.

Paratypes. (same data as the holotype, excepting date: March 1996 to March 2000) DZSJRP 6193, 5 [3 m, 2 f], 44.0– 73.8 mm SL; MZUSPAbout MZUSP 86208, 9 [4 m, 5 f], 45.7–77.6 mm SL; NUP 2528, 5 [3 m, 2 f], 53.0– 66.8 mm SL.

Diagnosis. Neoplecostomus corumba  can be distinguished from N. selenae  by lacking enlarged odontodes and distinct swollen skin along lateral margins of snout and along ridges before the eyes in mature males (vs present); from N. yapo  by lacking enlarged odontodes and distinct swollen skin along lateral margins of snout (vs present), by having smaller interdorsal length/ SL (18.4–20.5 vs 20.7 –23.0), and greater mandibullary width/HL (16.3–18.1 vs 14.1–15.2); from N. paranensis  by having well-developed adipose fin (vs reduced or absent), greater orbital diameter/HL (12.2 –13.0 vs 7.9 –12.0), and greater mandibullary width/HL (16.3–18.1 vs 8.4–12.4); from N. espiritosantensis  by having 10–18 dentary teeth (vs 19–38), greater cleithral width/ SL (24.9–27.6 vs 17.0–19.0), and greater orbital diameter/HL (12.2 –13.0 vs 6.0–9.0); from N. franciscoensis  and N. ribeirensis  by having a well-developed dorsal-fin spinelet, wider than dorsal-fin spine base (vs absent or narrower than dorsal-fin spine base); from N. granosus  by having 27–29 lateral-line plates (vs 34–43), and greater orbital diameter/HL (12.2 –13.0 vs 9.0–11.0); from N. microps  by having greater orbital diameter/HL (12.2 –13.0 vs 8.0–11.0); and from N. variipictus  by having smaller caudal peduncle depth/ SL (6.0– 6.5 vs 7.3– 7.8), greater orbital diameter/HL (12.2 –13.0 vs 9.1–9.9), 15–24 premaxillary teeth (vs 12–14), and 10–18 dentary teeth (vs 7).

Description. Counts and measurements are presented in Table 1. Body elongated and depressed. Greatest width at cleithrum, narrowing to caudal peduncle. Dorsal body profile gently convex, elevating from snout tip to dorsal-fin origin and descending to first caudal-fin procurrent spine. Greatest body depth at dorsal-fin origin. Trunk and caudal peduncle dorsally rounded in cross-section; body ventrally flattened to anal-fin origin, flattened to slightly rounded to caudal fin. Dorsal body surface completely covered by dermal plates, excepting for a naked area around dorsal-fin base. Snout tip naked. Ventral head surface naked except by a plate bearing odontodes in front of gill openings. Abdomen with conspicuous, small dermal platelets between insertions of pectoral and pelvic fins, forming a thoracic shield surrounded by naked areas; in some specimens also some isolated platelets near pectoral-fin base.

Character N. corumba  n = 20 N.  selenae n = 15 Head wide and moderately depressed. Head and snout weakly obtuse in dorsal view. Interorbital space slightly straight in frontal view. Median ridge from snout tip to area between nares weak or not evident. A ridge from naris to superior margin of orbit. Snout convex in lateral profile. Eye moderately small (12.2 –13.0 of HL), dorsolaterally placed. Lips well developed and rounded. Lower lip almost reaching pectoral girdle and covered by papillae, wider anteriorly; two or three irregular and conspicuous rows of large and transversally flattened papillae, just posterior to dentary teeth. Maxillary barbel short and mostly coalesced with lower lip, generally with free tip. Teeth long, slender and bicuspid; mesial cusp longer than lateral. Dentary rami forming an angle of approximately 120 o.

Dorsal-fin origin slightly posterior to vertical passing through pelvic-fin origin; nuchal plate not covered by skin; dorsal-fin spinelet half-moon shaped and wider than dorsal-fin spine base; dorsal-fin locking mechanism absent. Dorsal-fin with spine flexible, followed by seven branched rays; its posterior margin straight or slightly falcate, reaching about vertical through end of pelvic-fin rays when adpressed. Moderate to well developed and always present adipose fin, not preceded by azygous plate. Pectoral fin with six branched rays and a depressed and inward curved spine (more pronounced in larger specimens) shorter than longest branched ray; its posterior margin slightly falcate, reaching (in smaller specimens) or almost reaching half pelvic-fin length when adpressed. Pelvic fin with one spine and five branched rays; its posterior margin nearly straight, reaching or almost reaching anal-fin insertion when adpressed. Pelvic-fin spine ventrally flattened, with dermal flap on its dorsal surface in males. Anal fin with one flexible spine and five branched rays; its posterior margin straight. Caudal fin bifurcate; lower lobe longer than upper; 14 branched rays. Pectoral and pelvic-fin spines with odontodes on lateral and ventral portions. Anal-fin spine with odontodes only ventrally.

Color in alcohol. Ground color of dorsal surface of head and body yellowish. Head, dorsum, flanks and fins covered by many inconspicuous darker dots or blotches of variable shapes and sizes. Dorsal color pattern, even in mature larger individuals, retains the generic juvenile color pattern of five transverse dark bars: the first through supraoccipital, the second anterior to dorsal fin, the third posterior to dorsal fin, the fourth at adipose fin, and the last at caudal-peduncle posterior portion. Head usually with two light, short and parallel lines anterior to nares, bordering the naked area on snout tip. Orbital margin lighter, mainly on its superior portion. Small light spot on interorbital space, inconspicuous in some specimens. Few specimens with two almost parallel small lighter lines on suppraoccipital posterior part. Body lateral portion with an upper darker region and a lower lighter one, just below lateral line, not easily visualized in large specimens.

Dorsal fin with irregular series of dark dots on rays. Caudal fin irregularly dark at base and distal portion of rays, leaving two lighter areas on median portion and rays tips. Pectorals, pelvics, and anal fins with dark dots forming irregular bands usually diffuse. Adipose fin generally dark laterally and light on spine dorsal portion.

Ventral surface of head and body mostly unpigmented, except for some brown, faded scattered chromatophores near body lateral margins and from pelvic fin to caudal-fin base; upper lip dark brown, except for its light narrow margin.

Etymology. The specific name refers to the Rio Corumbá  , type-locality’s drainage. It is treated as a noun in apposition.

Distribution. Neoplecostomus corumba  is known only from the type-locality ( Fig. 3 View Figure ).

TABLE 1. Morphometric data and counts of Neoplecostomus corumba, N. selenae, N. yapo, and N. paranensis from the upper Rio Paraná basin. CP = caudal-peduncle, IO = interorbital length, OD = orbital diameter, PDS = predorsal, SL = standard length, ad = adipose-fin, an = anal-fin, cd = caudal-fin, ds = dorsal-fin.

  Mean/ Mode   Mean/ Mode
Standard length   11.21   101.7   15.79

TABLE 1. Morphometric data and counts of Neoplecostomus corumba, N. selenae, N. yapo, and N. paranensis from the upper Rio Paraná basin. CP = caudal-peduncle, IO = interorbital length, OD = orbital diameter, PDS = predorsal, SL = standard length, ad = adipose-fin, an = anal-fin, cd = caudal-fin, ds = dorsal-fin.

  Mean/ Mode   Mean/ Mode
Standard length   11.21   101.7   15.79
MZUSP

Museu de Zoologia da Universidade de Sao Paulo

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Siluriformes

Family

Loricariidae

Genus

Neoplecostomus

Loc

Neoplecostomus corumba

Zawadzki, Cláudio Henrique, Pavanelli, Carla Simone & Langeani, Francisco 2008

2008
Loc

Neoplecostomus

Zawadzki 2004: 574

2004