Hypostomus caudofasciatus, Zawadzki & Azevedo, 2024

Zawadzki, Cláudio Henrique & Azevedo, Filipe Manoel, 2024, Hypostomus caudofasciatus (Teleostei: Loricariidae), a new remarkably colored species from the upper Rio Paraná basin in Brazil, Zootaxa 5471 (3), pp. 318-328 : 319-323

Hypostomus caudofasciatus , new species urn:lsid:zoobank.org:act:117E6050-25BB-443E-8E48-F4BA3F01B72F

( Figs. 1 , 2 and 5 , Table 1 )

Holotype. NUP 24845, 143.7 mm SL, Brazil, São Paulo State, Guará, Rio Sapucaí-Mirim , tributary of Rio Grande, -20.49694, -47.86388, 28 Aug 2008, A. K. Oliveira, R. C. Torres & J. C. Garavello.

Paratypes. All from Brazil, São Paulo State (except when noted), upper Rio Paraná basin, Rio Grande basin : MCNIP 3445 , 1 , 93.7 mm SL; Barretos, Rio Pardo , -20.44972, -48.45583,1 Aug 2015, B. Becker, J. Ribeiro & B. Sanches. MCP 55039 , 2 , 88.9–127.8 mm SL; São Joaquim da Barra, Rio Sapucaí-Mirim , -20.54989, -47.81196; 1 Dec 2015, E. Brambilla & M. Nogueira. MNRJ 51846 , 2, 134.4– 145.8 mm SL, Guará, Rio Sapucaí-Mirim , -20.49694, -47.86388, 28 Aug 2008, A. K. Oliveira, R. C. Torres & J. C. Garavello. MZUSP 24783 , 3, 121.9– 134.6 mm SL, Delfinópolis, Minas Gerais State, Rio Grande , UHE Peixoto (currently UHE Mascarenhas de Moraes), -20.33333, -47.00000, 18 Dec 1975, CETESB. NUP 14997 , 2, 100.1– 161.4 mm SL, São Joaquim da Barra, Rio Sapucaí-Mirim , -20.54916, -47.81305; Aug 2012, D. F. Sousa, S. G. C. Britto & O. C. Foster. NUP 18414, 13, 85.7–158.3 mm SL, São Joaquim da Barra, Rio Sapucaí Mirim , -20.54916, -47.81305, 1 Dec 2015, E. Bambrilla & M. Nogueira. NUP 22318, 2, 136.8– 148.7 mm SL, São Joaquim da Barra, Rio Sapucaí-Mirim , -20.54972, -47.81194, 3 Dec 2019, C. H. Zawadzki, I. S. Penido & F. M. Azevedo. NUP 22688, 1, 83.4 mm SL, Guaíra in the border with Barretos, Rio Pardo , -20.45027, -48.45527, 6 Mar 2018, C. H. Zawadzki, I. S. Penido, G. Nardi & H. C. Proença. NUP 24846, 3, 109.2– 125.9 mm SL, Guará, Rio Sapucaí-Mirim , -20.49694, -47.86388, 2 Dec 2019, C. H. Zawadzki, I. S. Penido & F. M. Azevedo. NUP 24904, 4, 75.6–151.2 mm SL, Guaíra in the border with Barretos, Rio Pardo , -20.45027, -48. 45527, 5 Mar 2018, C. H. Zawadzki, I. S. Penido, G. Nardi & H. C. Proença .

Non-type specimens. All from Brazil, São Paulo State, Paraná State, Rio Paraná basin, NUP 17806, 6, 126.3– 171.0 mm SL, São Joaquim da Barra, Rio Sapucaí-Mirim, tributary of Rio Grande , -20.57250, -47.78269, 22 Mar 2012, D. F. Sousa, S. G. C. Britto & O. C. Foster. NUP 20039, 1, 135.7 mm SL, Rio Paraná ; -22.76305, -53.26972, 15 Apr 2000, M. F. S. R. Júlio & M. Kamei .

Diagnosis. Hypostomus caudofasciatus is distinguished from all congeners by having caudal fin with longitudinal dark stripes on yellow background (vs. caudal fin coloration plain, irregularly spotted or with transversal bands). Additionally, H. caudofasciatus is distinguished from congeners, except H. nigrolineatus , H. variipictus , H. luetkeni and H. margaritifer by having horizontally aligned stripes on lateral series of plates; from H. luetkeni by having one plate bordering supraoccipital and by having fewer upper-jaw teeth (21–39) (vs. three plates and 30–69 teeth see Mazzoni et al. 1994); from H. margaritifer by having dentary tooth rows straight (vs. J -shaped see Azevedo et al. (2021). It is distinguished from H. nigrolineatus by lacking keels on lateral series of plates (vs. having keels), and H. variipictus by having larger orbital diameter (20.7–25.0% in HL) (vs. 15.5–20.6% in HL).

Description. Counts and measurements in Table 1 . Overall view of body in figure 1. Head broad and stout. Body width at cleithral region almost twice head depth and almost equaling to head length. Snout and anterior profile of head rounded in dorsal view. Snout in lateral profile rising from horizontal at approximately 40°. Dorsal profile nearly straight rising from snout tip to interorbital area, then rising slightly convex to dorsal-fin origin; sloped downward from dorsal-fin origin to region of dorsal procurrent caudal-fin rays, then elevating again to caudal-fin origin. Caudal peduncle high, strongly compressed on its posterior most portion; dorsally flattened on its anterior portion and ventrally flattened along its full extent. Eye remarkable large comparatively to congeners (20.7–25.0% HL), dorsolaterally positioned. Iris operculum present, variable in size according to light exposure in live specimens. Supraorbital not to slightly raised. Interorbital area wide and flat in frontal view. Mesethmoid area with inconspicuous median ridge on mid-dorsal region of snout, depending on fixation. Weak bulge on dorsal surface of head, from nares to upper margin of eyes. Cheek plates without distinguishable hypertrophied odontodes. Cleithral process long and shallow in lateral view, its upper border concave; posterior border sharp. Supraoccipital flat; with short median posterior process limited by one predorsal plate. Dorsal and lateral surface of head and body covered with dermal plates, except for small naked area on snout tip and dorsal-fin base. Predorsal region flat. Trunk covered by five lateral series of dermal plates; all plates lacking either longitudinal keels or distinguishable hypertrophied odontodes. Dorsal series bent to form flat area from dorsal-fin origin to caudal-fin origin. Median series bearing lateral line. Mid-ventral series strong bent from cleithral process to fourth or fifth plate. Ventral series bent to form flat caudal peduncle floor.

Mouth moderate to large with transverse oval lips. Outer surface of upper lips with odontodes; inner surface with short papillae. Lower lip far from reaching gill opening, its inner surface covered with numerous small papillae, larger proximally. Maxillary barbel small to moderate in size, shorter than orbital diameter. Inside mouth, small and rounded papillae bordering both dentaries and maxillaries; conspicuous central buccal papilla, with distal tip usually rough. Teeth moderately robust with ventrally bent crown. Crown with lanceolate main cusp and smaller and sharp lateral cusp. Intermandibular tooth row angle approximately from 122°–130°, mean 125.5° and standard deviation 2.7.

Lower surface of head beneath lower lip and at medial region naked; area anterior to gill openings plated. Pectoral bridge and abdomen usually lacking platelets in specimens up to 50.0 mm SL; specimens around 80.0 mm SL usually with irregular platelet area concentrated mainly anteriomedially on abdomen (NUP 18414). Dorsal fin II,7; first element short, modified as spinelet, V -shaped; second element modified as flexible spine. Dorsal fin moderate in size; its distal border slightly convex; typically, just reaching adipose-fin azygous plate posteriorly. Adipose-fin spine relatively large, inflexible, curved inward, with distal tip almost reaching anteriormost caudal-fin procurrent ray. Pectoral fin I,6; its border straight. Pectoral-fin spine inflexible, slightly curved inward, usually proximally depressed and distally round with hypertrophied odontodes, mainly in larger specimens; when adpressed, reaching middle of pelvic-fin unbranched ray. Pelvic fin i,5; its border slightly convex. Pelvic-fin unbranched ray flexible, curved medially; when adpressed surpassing anal-fin unbranched-ray origin. Anal fin i,4; when adpressed, distal tip of posterior rays reaching fifth to sixth plate posterior to its origin. Caudal fin i,7+7,i; emarginate, with ventral lobe equal to slightly longer than dorsal lobe.

Color in alcohol. Ground color of body dorsal surface and fins grayish-brown and covered with many dark spots, blotches, vermiculations and/or stripes. Wide dark vermiculations usually covering laterodorsal surface of head and predorsal region of trunk. On dorsolateral surface of trunk, dark blotches tend to fuse into four horizontally aligned stripes, with first dark stripe at upper portion of dorsal series, bordering dorsal and adipose fins; second between edge of dorsal and mid-dorsal series; third at edge between mid and mid-ventral series; and fourth along margin of mid-ventral and ventral series. Fourth stripe sometimes faded. On dorsal fin, dark marks as longitudinal stripes along each intermembrane or dark marks as two to three transverse bands. Sometimes both patterns merged with one proximal transverse band and distal longitudinal stripes on intermembrane area. Pectoral and ventral fins irregularly marked with diffuse dark blotches merging into longitudinal marks. On caudal fin, the pattern of diffuse dark blotches merging into longitudinal stripes is much more conspicuous. In some specimens, all dark stripes on caudal fin are well defined. In other specimens median unbranched rays with longitudinal stripes and external rays with moderately curved or forming C -shaped bands. Anal fin usually beige, lacking color marks, obscure or faded. Ventral surface of body lighter than dorsal surface mainly on head and abdominal regions; without spots.

Color in life. Color pattern similar to that observed in preserved specimens, except that the body and fins present from yellowish to intense yellow background and darker marks ( Fig. 2 ). Eye with iris yellowish-browned; darker on its dorsal region; narrow golden yellow ring bordering black pupil.

Distribution and habitat. Specimens of Hypostomus caudofasciatus were collected in the some of the tributaries of the Rio Grande basin, as the Rio Sapucaí-Mirim, Rio Pardo and at the main channel of the Rio Grande itself ( Fig. 3 ) and a single specimen was collected in the Rio Paraná main channel. In the Rio Sapucaí-Mirim, the new species co-occurs with H. heraldoi , H. margaritfer , H. nigromaculatus ( Oliveira et al. 2015) and H. variipictus ( Azevedo et al. 2021) . Most specimens were collected in small and medium-sized streams with ranges from 30 cm to 5 m depth. A few specimens were also captured on the ladder of the UHE Palmeiras ( Fig. 4 ). The streams usually have substrates with sand, clay, and loose gravel, and sometimes pebbles and boulders. Specimens were collected in rapids as well as in pools along these localities.

Etymology. From the Latin cauda (tail) and fasciatus (stripes), referring to the longitudinal dark stripes on the caudal fin.

Conservation status. Hypostomus caudofasciatus is known from a few localities along the Rio Paraná basin. Specimens were found in stretches of the Rio Grande basin and a single point in the upper Rio Paraná ( Fig. 3 ). Hypostomus caudofasciatus may be widely spread in the Rio Grande basin despite having few records; we estimated the extent of occurrence (EOO) based on the whole drainage area of 143,000 km 2. Therefore, H. caudofasciatus may be categorized as Least Concern (LC) according to the International Union for Conservation of Nature ( IUCN, 2022).

Figures

FIGURE 1. Hypostomus caudofasciatus, NUP 24845, holotype, 143.7 mm SL; Brazil: São Paulo State: Guará, Rio Sapucaí- Mirim, upper Rio Paraná basin.

FIGURE 2. Hypostomus caudofasciatus, photographed alive in lateral view, NUP 24846, 108.3 mm SL, upper and NUP 22318, 136.8 mm SL, below. All from Brazil, São Paulo State: Rio Sapucaí-Mirim, upper Rio Paraná basin.

FIGURE 3. Distribution of Hypostomus caudofasciatus. Red star = type localiy; black circles = paratypes locality; orange triangle = non-type locality.

FIGURE 4. Rio Sapucaí-Mirim, tributary of Rio Grande, upper Rio Paraná basin, Brazil, São Paulo State, showing type habitat of Hypostomus caudofasciatus.

FIGURE 5. a) Hypostomus caudofasciatus n. sp., live specimen showing caudal fin with the dark stripes on a yellow background, NUP 22318, 136.8 mm SL; b) Hypostomus heraldoi, live specimen (not preserved) showing caudal fin with dark spots aligned to form transversal bars; c) Hypostomus variipictus, live specimen NUP 22317, 193.5 mm SL showing caudal fin with transversal dark bands; d) Hypostomus margaritifer, live specimen (not preserved) showing caudal fin with pale spots; e) Hypostomus paulinus, live specimen (not preserved) with caudal fin homogeneously colored.