Proloricaria prolixa (Isbrücker & Nijssen, 1978)

Proloricaria prolixa (Isbrücker & Nijssen, 1978) View in CoL

( Figs. 6–7)

Loricaria prolixa Isbrücker & Nijssen, 1978:189–94 (part; original description, type-locality: Piracicaba River). ―Ferraris, 2003:337 (catalogue of Neotropical freshwater fish). ―Ghazzi, Oyakawa, 2007:89 (catalogue, freshwater fishes of Brazil). ―Graça, Pavanelli, 2007:120 (catalogue, upper Paraná River basin). ―Langeani et al., 2007:188 ( Borá River , Tietê drainage). ―Ota et al., 2018:77 (diagnosis, upper Paraná River floodplain).

Loricaria macrodon (non Kner, 1853). ―Miranda-Ribeiro, 1918:718 (part, list, Piracicaba River). ―Fowler, 1954:96 (part, catalogue, Piracicaba River).

Proloricaria prolixa . ―Isbrücker et al., 2001:21 (diagnosis of Proloricaria ). ―Isbrücker, 2001:31 (list of Loricariidae species). ―Ferraris, 2007:286 (catalogue of Siluriformes ). ―Froehlich et al., 2017:8 (checklist, Mato Grosso do Sul). ―Jarduli et al., 2020:11 (literature revision, Panapanema River). ― Dagosta et al., 2024:23 (geographic distribution).

Diagnosis. Proloricaria prolixa is distinguished from its congener by having a dark transverse bar between the nostrils and the anterior margin of the orbits followed by another clear bar, positioned over the orbits ( vs. dark transverse bar absent in P. lentiginosa ) ( Fig. 8); none, rarely one or two, pair of plates anterior to the series of predorsal paired plates ( vs. pair of anterior plates, one on each side (rarely in just one side, or none), in P. lentiginosa ). Parieto-supraoccipital normally with one or two rows of well-developed odontodes ( vs. one row in P. lentiginosa ).

Description. Morphometric data summarized in Tab. 3. Standard length of specimens examined 44-415 mm. Body elongate, dorsoventrally depressed, widest in cleithrum. Ventral profile slightly convex, mostly flat. Greatest body depth at dorsal-fin origin. Head triangular in dorsal view, with round snout and slightly convex lateral margins from snout tip to operculum. Head dorsal profile straight and inclined from tip of snout to anterodorsal margin of orbit, and slightly inclined to posterior elevated margin of parieto-supraoccipital. Eye small, maximum orbital diameter 10.1–18.5% in HL. Post orbital notch absent.

Ventral mouth, thin lips with small, thin, simple or bifid barbels. Upper lip barbels longer than lower lip, more numerous, and distributed over entire surface. Rictal barbel long, occasionally reaching the gill openings, branched, with simple or bifid secondary barbels similar to those on upper lip. Lower lip broad, with smaller and more dispersed barbels relative to those on the upper lip. Posterior edge of lower lip rounded, with shallow median notch; barbels more elongated than others on its surface. Teeth in both maxillae. Each tooth with a small lateral cusp and longer main cusp, with rounded tips. Premaxillary teeth one to five (modally three) on each side, curved towards the inside of the mouth. Dentary teeth three to nine (modally six) on each side; less than half the length of premaxillary teeth and shorter cusps.

Body completely covered with dermal plates, except the ventral surface of the head, portions of thorax and abdomen, around bases of pectoral and ventral fins, and areas lateral and posterior to anus. Abdomen with small and minute bony plates, partially naked in young specimens. Parieto-supraoccipital and predorsal plates with odontode crests. Each dorsolateral and lateral plates with one crest of odontodes.

Dorsal-fin fin rays I,7, with posterior margin straight; reaching the fourth or fifth posterior dorsal plate when adpressed. Pectoral-fin rays I,6, with distal margin curved or slightly convex; the spine, when adpressed, surpassing the half-length of pelvic-fin spine. Pelvic-fin rays I,5, with convex distal margin, spine much longer than branched rays, surpassing the anal-fin base when adpressed. Anal-fin rays I,5, reaching the fifth sixtieth postanal plate when adpressed, with distal margin convex. Principal caudal-fin rays I,10,I; posterior margin of fin deeply concave; upper unbranched ray produced into a long trailing filament with at least half of standard length (broken in most specimens examined).

Coloration in alcohol. Ground color of dorsum of the head and body greyish tan to pale yellow. Ventral region of head and body whitish to pale yellow. Several rounded grayish-brown dots, generally much small, well defined, and relatively concentrated on the back of the head, but inconspicuous or absent in some specimens. Tiny dots can be distributed both anteriorly and posteriorly on the back of the head, those in the posterior part of head and anterior part of body larger. Head with a dark transverse bar passing through the nostrils, reaching the anterior margin of the orbits, usually followed by another light transverse bar passing through the orbits. Dorsum of body with larger, poorly defined, and less concentrated blotches relative to those on head, with an irregular distribution, sometimes forming a zigzag longitudinal row on each side of the dorsal surface of the body, in the region between the series of dorsal and lateral plates. Conspicuous dark grey transverse bars on dorsum of the body in small (up to 200 mm SL) specimens, pale or absent on greater specimens.

Dorsal-fin brownish, with dark spots on spine and branched rays arranged in oblique irregular bands. Pectoral-fin brownish, darker than other fins, with irregular dark spots in spine, branched rays and membranes, forming irregular bands on its entire surface. Pelvic-fin pale, with dark spots on spine and branched rays. Anal-fin pale, with faint spots on spine, and inconspicuous spots on branched rays. Caudal-fin brownish, with dark spots on rays arranged in three to four vertical irregular bands. The same color pattern is observed in living and recently collected specimens, but the dark pigmentation is more conspicuous than in older specimens.

Sexual dimorphism. Dissection of seven specimens (LISDEBE 7826, three females, 309–322 mm SL; LISDEBE 7709, female, 346 mm SL; LISDEBE 7826, male, 317 mm SL; LISDEBE 7709, male, 315 mm SL; and LISDEBE 7710, male, 331 mm SL) revealed sexual dimorphic traits similar to those observed in P. lentiginosa .

Geographical distribution. Proloricaria prolixa is widely distributed in the upper Paraná River basin (except in the Grande River basin), in states of Goiás, Minas Gerais, Mato Grosso do Sul, Paraná and São Paulo ( Fig. 5). It occurs in small to large riverine habitats with sandy and rocky bottom .

Material examined. All from Brazil. Goiás: LIRP 8377 View Materials , 4 View Materials , 169.0–259.0 mm SL ; LIRP 7299 View Materials , 1 View Materials , 228.0 mm SL ; LIRP 6942 View Materials , 1 View Materials , 159.0 mm SL ; LIRP 6937 View Materials , 1 View Materials , 213.0 mm SL ; LIRP 6635 View Materials , 1 View Materials , 225.0 mm SL. Paraná : MZUSP 13394 View Materials , paratype, 343.0 mm SL ; MZUSP 21650 View Materials , 4 View Materials , 273.0–409.0 mm SL ; LIRP 7545 View Materials , 4 View Materials , 269.0–352.0 mm SL. São Paulo : MZUSP 13186 View Materials , paratype, 230.0 mm SL ; MZUSP 333 View Materials , paratype, 303.0 mm SL ; MZUSP 3104 View Materials , 1 View Materials , 209.0 mm SL ; MZUSP 3243 View Materials , 1 View Materials , 363.0 mm SL ; MZUSP 22238 View Materials , 1 View Materials , 346.0 mm SL ; MZUSP 23071 View Materials , 16 View Materials , 85.0–341.0 mm SL ; MZUSP 87134 View Materials , 1, 104.8 mm SL ; MZUSP 413 View Materials , 1 View Materials , 277.0 mm SL ; MZUSP 24436 View Materials , 2 View Materials , 67.5 View Materials – 326.0 mm SL ; MZUSP 37986 View Materials , 3 View Materials , 218.0–364.0 mm SL ; MZUSP 24380 View Materials , 2 View Materials , 327.0–364.0 mm SL; LISDEBE 7657, 3, 271.0–315.0 mm SL; LISDEBE 6071, 1, 180.0 mm SL; LISDEBE 4409, 1, 273.0 mm SL; LISDEBE 4485, 1, 224.0 mm SL; LISDEBE 3464, 1, 267.0 mm SL; LISDEBE 3463, 1, 274.0 mm SL; LISDEBE 7709, 4, 297.0–400.0 mm SL; LISDEBE 7710, 2, 313.0–330.0 mm SL; LISDEBE 4408, 5, 219.0–265.0 mm SL; LISDEBE 4473, 4, 206.0–305.0 mm SL; LISDEBE 7891, 6, 321.0–360.0 mm SL; LISDEBE 7892, 1, 415.0 mm SL; LISDEBE 7826, 12, 174.0–350.0 mm SL ; DZSJRP 6312 , 2 , 105.0–116.0 mm SL ; DZSJRP 21342 , 2 , 233.0–289.0 mm SL ; DZSJRP 5388 , 1 , 44.0 mm SL ; LIRP 7569 View Materials , 2 View Materials , 257.0–264.0 mm SL .