Ancistrus agostinhoi, 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 : 47-50

Ancistrus agostinhoi , n. sp.

Figure 4 ; Tables 2, 4

Holotype. MZUSP 104118 [male], 96.1 mm SL, Brazil, Paraná State, Foz do Jordão, lower Rio Iguaçu basin, Rio Jordão, 25°39'12"S / 51°58'15"W, Nupélia, 24 Dec 2005.

Paratypes. All collected in Brazil, Paraná State, lower Rio Iguaçu basin. Measurements presented refer to SL in mm: MHNCI 7651, 1, 64.6, Pinhão, Rio Jordão, upstream Lutscher dam, W. Wosiacki et al., 22 Oct 1991; MHNCI 7658, 1, 63.9, Rio Jordão, mouth of Rio Estreito, W. Wosiacki et al., 23 Oct 1991; MHNCI 7671, 1, 58.3, Pinhão, Rio Jordão, downstream Lutscher dam, W. Wosiacki et al., 20 Oct 1991; MHNCI 7731, 1, 57.9, Pinhão, Rio Jordão, downstream Lutscher dam, W. Wosiacki et al., 24 Oct 1991; MHNCI 10707, 4, 60.2–68.2, Pinhão, affluent of Rio Jordão, Rio Pinhão, A. Schwarz & H. Vollweiter, 2 Jan 1999; MZUSP 104119, 2, 70.7–85.1, same data of the holotype; MZUSP 104120, 2, 76.3–84.2, Guarapuava, affluent of Rio Jordão, Rio das Pedras, 25°23’59”S / 51°26’23”W, L.L. Wolff, 11 Jun 2004; NUP 3737, 16, 17.9–69.0, Candói, affluent of Rio Jordão, Rio Candói, 25°40’58”S / 51°59’54”W, Nupélia, 9 Apr 2005; NUP 3738, 1, 79.6, Candói, Rio Jordão, 25°40’07”S / 51°58’16”W, Nupélia, 8 Apr 2005; NUP 3782, 1, 67.0, Candói, Rio Jordão, 25°38’56”S / 51°58’26”W, Nupélia, Apr 2005; NUP 3788, 2, 68.5–73.7, Candói, Rio Jordão, 25°38’56”S / 51°58’26”W, Nupélia, Apr 2005; NUP 4061, 1, 52.8, Pinhão, affluent of Rio Jordão, Rio Capivara, 25°38’07”S / 51°52’40”W, Nupélia, Apr 2005; NUP 4065, 1, 58.6, Pinhão, affluent of Rio Jordão, Rio Sobradinho, 25°39’41”S / 51°54’13”W, Nupélia, Apr 2005; NUP 4072, 1, 56.2, Pinhão, Rio Jordão, 25°39’12”S / 51°58’15”W, Nupélia, Apr 2005; NUP 4319, 2, 91.2–92.5, Guarapuava, affluent of Rio Jordão, Rio das Pedras, 25°23’59”S / 51°26’23”W, L.L. Wolff, 11 Jun 2004; NUP 4320, 2, 88.8–90.7, Foz do Jordão, Rio Jordão, 25°46’17”S / 52°06’51”W, Nupélia, Nov 1999; NUP 5130, 4, 13.0–66.6, Pinhão, affluent of Rio Capão Grande, Rio das Torres, 25°48’26”S / 51°59’24”W, Nupélia, 23 Nov 1995; NUP 5135, 1, 75.9, Foz do Jordão, Rio Jordão, 25°46’17”S / 52°06’51”W, Nupélia, 15 Dec 1997; NUP 5140, 7, 51.8–95.9, same data as the holotype; NUP 5225, 56, 18.2–69.1, Reserva do Iguaçu, Rio Jordão, 25°44’58”S / 52°04’16”W, Nupélia, 18 Apr 1995.

Non-measured paratypes. NUP 1657, 4, 23.2–26.6, Foz do Jordão, Rio Jordão, 25°39'12"S / 51°58'15"W, Nupélia, Aug 1995; NUP 4020, 1, 43.7, Guarapuava, Rio Jordão, 25°26’17”S / 51°30’35”W, C.H. Zawadzki, Nov 2003.

Diagnosis. Ancistrus agostinhoi is diagnosed from congeners inhabiting the Río de La Plata and coastal basins of southern Brazil, except A. abilhoai , A. formoso , A. mullerae , A. multispinis and A. taunayi by having maxillary barbel shorter and not free from lower lip (vs. longer and free from lower lip); from A. abilhoai by width of mandibulary teeth row (15.8–19.3% of HL vs. 13.4–15.5% and 38.4–53.6% of interorbital width vs. 32.9–37.9%); from A. formoso by orbital diameter (12.3–17.3% of HL vs. 8.3–8.7%), caudal peduncle depth (10.6–12.0% of SL vs. 7.8–8.7%) and number of dentary teeth (38–78 vs. 110); from A. multispinis and A. taunayi by occipital depth (18.8–22.0% of SL vs. 16.2–18.0% and 17.3–17.9%, respectively); from A. mullerae by occipital depth (18.8–22.0% of SL vs. 15.4–18.8%) and head length (37.8–41.4% of SL, mean= 38.9% vs. 34.4–37.9%, mean= 36.3%).

Description. Morphometric data presented in Table 2 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 concave to end of caudal peduncle. Ventral profile of body straight, slightly concave on ventral portion of caudal peduncle; caudal peduncle elliptical, tall and short, 24.3–29.4% 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 small to middle-sized, with slightly raised dorsal margin. Interorbital region slightly concave. Exposed portion of opercle usually somewhat triangular, rounded anteriorly; post-opercular 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).

Dorsal-fin origin situated slightly anterior to vertical through pelvic-fin origin; dorsal fin when adpressed usually 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 obliquely truncate; lowermost spine slightly longer than superior. Fin-ray formulae: dorsal I7 (one specimen presenting I8, lot NUP 4061); pectoral I6; pelvic I5; anal I3–4; caudal I14 I.

Sexual dimorphism. Males are usually larger than females; largest male and female with 96.1 mm and 76.3 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 dark-gray; usually with light-brown, irregular, small dots over body, more defined over head. Lips yellowish. Ventral region of body dark-gray to anal fin, with diffuse, lightbrown, round dots or vermiculations. Fins yellowish, with dark-gray dots forming three to five stripes on even fins, and four or five on odd fins.

Etymology. The species name, agostinhoi , is in honor of Ângelo Antônio Agostinho, in recognition of his myriad contributions to our knowledge of ecology of Neotropical fishes, and his great participation in the establishment of the Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura, Nupélia, one of the most important centers of research in ecology of fishes of the Latin America. A patronym.

Distribution. Ancistrus agostinhoi is only known from the Rio Jordão drainage, affluent of lower Rio Iguaçu, Southern Brazil ( Fig. 3 ).

Figures

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).

FIGURE 4. Ancistrus agostinhoi, MZUSP 104118, holotype, 96.1 mm SL; Brazil, Paraná, lower Rio Iguaçu basin, Rio Jordão, affluent of Rio Iguaçu.