Ancistrus abilhoai, Bifi, Alessandro Gasparetto, Pavanelli, Carla Simone & Zawadzki, Cláudio Henrique, 2009

Bifi, Alessandro Gasparetto, Pavanelli, Carla Simone & Zawadzki, Cláudio Henrique, 2009, Three new species of Ancistrus Kner, 1854 (Siluriformes: Loricariidae) from the Rio Iguaçu basin, Paraná State, Brazil, Zootaxa 2275, pp. 41-59 : 42-44

Ancistrus abilhoai , n. sp.

Figure 1 ; Tables 1 , 4

Ancistrus sp. Severi and Cordeiro, 1994: 81 (check list; upper Rio Iguaçu basin; illustrated). – Ingenito et al., 2004: 28 (check list; Rio Iraí and Rio Turvo, upper Rio Iguaçu basin; fig. of page 32).

Holotype. MZUSP 104116 [male], 99.3 mm SL, Brazil, Paraná State, Lapa, middle Rio Iguaçu basin, Rio Iguaçu, 25°47’35”S / 50°11’59”W, L.F. Duboc, 11 Dec 2002.

Paratypes. All collected in Brazil, Paraná State. Measurements presented refer to SL in mm. Upper Rio Iguaçu basin: MCP 18278, 1, 65.0, Piraquara, Rio Piraquara, 25°28’S / 49°04’W, W. Boeger & F. Popazoglo, 2 Mar 1993; MHNCI 8429, 1, 59.1, Araucária, Rio Passaúna, J. Ribeiro & A.A.M. Cordeiro, 9 Oct 1986; MHNCI 8521, 1, 82.0, Araucária, Rio Passaúna, J. Ribeiro & A.A.M. Cordeiro, 23 Sep 1986; MHNCI 8574, 1, 78.4, Araucária, Rio Passaúna, J. Ribeiro & A.A.M. Cordeiro, 2 Oct 1986; MHNCI 8620, 1, 82.4, Campo Largo, Rio Verde, 8 Nov 1988; MHNCI 10456, 1, 83.7, Curitiba, Passaúna Reservoir, 9 Oct 1990; MHNCI 11390, 2, 79.0–83.0, Quatro Barras, Rio Iraí, V. Abilhoa, 5 Apr 1998; MZUSP 104117, 3, 79.2–91.9, Araucária, Rio Passaúna, J. Ribeiro & A.A.M. Cordeiro, 2 Oct 1986; NUP 7508, 2, 66.2–71.4, Araucária, Rio Passaúna, J. Ribeiro & A.A.M. Cordeiro, 9 Oct 1986; NUP 7509, 3, 34.7–81.5, Araucária, Rio Passaúna, J.

Ribeiro & A.A.M. Cordeiro, 23 Sep 1986. Lower Rio Iguaçu basin: NUP 7502, 2, 105.6–106.2, Cruz Machado, Rio Iguaçu, Foz do Areia Reservoir, 26°00’S / 51°37’W, Copel, Jul 2002.

Non-measured paratypes. All collected in Brazil, Paraná State, upper and middle Rio Iguaçu basin: MCP 10435, 1, 50.2 mm SL, Mandirituba, 25°47’S / 49°20’W, N.N. Fontoura, 7 Jun 1985; MCP 10636, 1, 27.3, Rio Negro, Rio Negro, 26°11’S / 49°43’W, C.A.S. Lucena, 20 Sep 1985; MCP 18277, 1, 30.0, Piraquara, Rio Piraquara, 25°28’S / 49°04’W, W. Boeger & F. Popazoglo, 9 May 1994; MHNCI 10403, 1, 36.7, Piraquara, Rio Itaqui, 1 Dec 1988.

Diagnosis. Ancistrus abilhoai is diagnosed from congeners inhabiting the Río de La Plata and coastal basins of southern Brazil, except A. agostinhoi , A. formoso , A. multispinis , A. mullerae and A. taunayi , by having maxillary barbel shorter and not free from lower lip (vs. longer and free from lower lip); from A. agostinhoi , A. multispinis , A. mullerae and A. taunayi by width of mandibulary teeth row (13.4–15.5% of HL vs. 15.8–19.3%, 15.5–19.4%, 16.5–21.0% and 15.8–23.1%, respectively, and 32.9–37.9% of interorbital width vs. 38.4–53.6%, 40.7–53.8%, 39.3–58.0% and 39.4–51.4%, respectively); from A. formoso by orbital diameter (11.9–15.3% of HL vs. 8.3–8.7%), caudal peduncle depth (9.0–10.9% of SL vs. 7.8–8.7%) and number of dentary teeth (40–68 vs. 110).

Description. Morphometric data presented in Table 1 and counts in Table 4. Head and body depressed. Dorsal profile of head and trunk convex from tip of snout to supraoccipital, then slightly convex to adipose fin and slightly concave to end of caudal peduncle. Ventral profile of body straight, slightly concave on ventral portion of caudal peduncle; caudal peduncle elliptical and short, 26.2–30.5% of SL.

Snout rounded in dorsal view, with naked margin bordered by dermic platelets of variable lengths on its lateral portion; naked area larger in males. Adult males with small- to middle-sized tentacles, unbranched on dorsal region of snout and aligned small tentacles along snout border. Females usually with two very small tentacles on each side of snout border.

Eye middle-sized, with slightly raised dorsal margin. Interorbital region slightly concave. Exposed portion of opercle usually somewhat triangular, rounded anteriorly; postopercular region with few platelets near to pterotic-supracleithrum, naked on its anterior portion.

Rounded oral disk with small papillae; lower lip wide with papillae reducing in size toward its margin; maxillary barbel short, coalesced to lower lip ( Fig. 2 ). Premaxillary and dentary teeth short, numerous, bifid; lateral cusp reduced, the mesial larger and wider.

Supraoccipital with margins between surrounding bones and plates not clearly visible; delimited posteriorly by first line of predorsal plates. Five lateral series of plates, three lateral series on the narrower portion of caudal peduncle. Mid-dorsal and mid-ventral series not surpassing adipose fin. Short odontodes present on fin rays, and body plates. Abdomen entirely devoid of plates. Base of first anal-fin pterygiophore covered by skin (without externally preanal platelet-like element), except in one specimen (lot NUP 7502).

Dorsal-fin origin situated slightly anterior to vertical through pelvic-fin origin; dorsal fin when adpressed usually not reaching preadipose plate; dorsal-fin spine short. Adipose-fin spine short, slightly curved inward. Pectoral-fin spine with odontodes hypertrophied and tentacles on its distal portion; pectoral-fin length variable, usually surpassing a half length of adpressed pelvic fin. Depressed pelvic-fin spine surpassing origin of anal fin. Anal fin short. Caudal-fin margin slightly concave; lowermost spine slightly longer than superior. Fin-ray formulae: dorsal I7; pectoral I6; pelvic I5; anal I3–4; caudal I14 I.

Sexual dimorphism. Males are usually larger than females; largest male and female with 106.2 mm and 84.9 mm SL, respectively. Mature males have small- to middle-sized tentacles on dorsal region and border of snout. Females can have few shorter tentacles, usually two on each side of snout.

Color in alcohol. Background color brown; light-brown, irregular, small dots over body, middle-sized on head and trunk, and smaller on snout, more defined over head. Lips yellowish. Ventral region of body brownish to anal fin, with diffuse, pale, round dots or vermiculations. Fins yellowish, with dark-brown dots forming three or four stripes or greater round blotches. Sometimes this color pattern can happen in reverse.

Etymology. The species name, abilhoai , is in honor of Vinícius Abilhoa, who has collected some specimens that served as the basis for the species description, and who has been of great assistance to the authors in this and other studies as curator of the Collection of Fishes of the Museu de História Natural do Capão de Imbuia (MHNCI) in Curitiba. A patronym.

Distribution. Ancistrus abilhoai is more commonly found in upper and middle Rio Iguaçu basin, Southern Brazil, and one single lot at lower Rio Iguaçu ( Fig. 3 ). Additional comments are provided in the discussion.

Figures

FIGURE 1. Ancistrus abilhoai, MZUSP 104116, holotype, 99.3 mm SL; Brazil, Paraná, Lapa, upper Rio Iguaçu basin, affluent of Rio Iguaçu.

FIGURE 2. (A) barbel not free from the lower lip (e. g. Ancistrus mullerae); (B) barbel short and free from the lower lip (e. g. Ancistrus pirareta); and (C) barbel long and free from the lower lip (e. g. Ancistrus cuiabae). Scale bar = 1 mm.

FIGURE 3. Geographic distribution and type-localities of Ancistrus abilhoai (dot, square = type-locality), Ancistrus agostinhoi (diamond, asterisk = type-locality) and Ancistrus mullerae (triangle, star = type-locality). Salto Caiacanga (1) and Salto Grande (2) split upper, middle and lower Rio Iguaçu basin. Foz do Areia dam (A), Salto Segredo dam (B) and Salto Caxias dam (C).