Pseudacanthicus pitanga, Chamon, Carine C., 2015

Chamon, Carine C., 2015, Pseudacanthicus pitanga: a new species of Ancistrini (Siluriformes: Loricariidae: Hypostominae) from rio Tocantins Basin, North Brazil, Zootaxa 3973 (2), pp. 309-320 : 310-314

Pseudacanthicus pitanga sp. nov.

( Figs. 1–2 ; Tab. 1 )

Holotype. MZUSP 34296, 220.7 mm SL, Serra dos Carajás, bedrock at rio Itacaiunas, Serra dos Carajás, Pará, Brazil, 05032'00"W 0552'00"S, Nov 1983, M. Goulding.

Paratypes. Brazil. Pará State. INPA 4502, 1, 164.1 mm SL, rio Tocantins, Tucuruí, 345'39.16"S, 4939'50.85"W, 0 1 May 1986, F. Martinho. INPA 4558, 4, 91.4–147.5, rio Tocantins, downstream to Tucuruí Dam, 346'2.84"S, 4939'36.68"W, 0 9 Oct 1984, G. M. dos Santos. INPA 4559, 1, 148.1 mm SL, poço do Paulo, rio Tocantins, Tucurui, 345'31.63"S, 4939'50.75"W, 26 Jul 1980, Equipe Ictiologia INPA (Lucia Rapp Py Daniel et al). INPA 6308, 1, 94.1 mm SL, Tucurui, downstream to Tucuruí Dam, 345'58.19"S, 4939'43.57"W. INPA 6311, 7, 30.2–230.3 mm SL, rio Tocantins, 345'59.43"S, 4939'40.41"W. INPA 6348, 1, 270.0 mm SL, rio Tocantins, Jatobal, 428'26.61"S, 4927'18.23"W, 0 5 Jul 1982, M. Jegu. INPA 6349, 1, 252.0 mm SL, Igarapé Jatobal, Tucuruí, 31 Oct 1980, Equipe Ictiologia INPA. INPA 6350, 1, 300.0 mm SL, rio Tocantins, Breu Branco, 44'4.52"S, 4938'12.87"W, 31 Oct 1980, Equipe Ictiologia INPA. INPA 10919, 1, 210.4 mm SL, rio Tocantins, downstream to Tucuruí Dam, 0345'58”S, 04940'21”W, 0 1 Nov 1980, Equipe Ictiologia INPA. MZUSP 24135, 1, 110.7 mm SL, rio Tocantins, lagoon in front of Jatobal, Jatobal, 04939'00"W 0434'00"S, 16 Sep 1970, Expediçao; à Permanente a Amazônia (Heraldo A. Britski et al.). MZUSP 34295, 6, 170.3– 256.9 mm SL, 1 esq., 236,3 mm SL, rio Itacaiunas, Caldeirão, 05032'00"W 0552'00"S, 0 4 May 1983, M. Goulding. MZUSP 115275, 1, 181.1 mm SL, collected with the holotype. Tocantins State. UNT 857, 1, 170.1 mm SL, rio Tocantins, Brejinho de Nazaré, 115'24"W 4834'19"S, 17 Nov 1997, Equipe Neamb (Anderson B. Soares et al). UNT 960, 1, 200.7 mm SL, rio Tocantins, Brejinho de Nazaré, 115'24"W 4834'19"S, 18 Set 2003, Equipe Neamb. UNT 967, 1, 87.3 mm SL, rio Tocantins, Fazenda Traçadal, Paranã, 1228'099"W 4814'47"S, 27 Jul 1999, Equipe Neamb. UNT 8505, 1, 259.0 mm SL, rio Tocantins, near the confluence with rio Santo Antônio, Peixe, 1131'17"W 4837'59"S, 17 Oct 2001, Equipe Neamb. UNT 9061, 1, 224.2 mm SL, rio Maranhão at the place of UEH São Salvador, São Salvador, 1248'55"W 4814'45"S, 18 Jun 2006, A. Santana. UNT 1109, 1, 146.8 mm SL, rio Sono, Pedro Afonso, 859'54"W 4814'17"S, 10 Ago 2001, Equipe Neamb. UNT 10297, 1, 228.5 mm SL, rio Tocantins, border of Miracema and Tocantínia, 942'59"W 4821'39"S, May 2009, Equipe CMT Ambiental.

Non-type material. Brazil, Pará state, rio Tocantins. ZMA 119.395, 3, 88.5–89.2 mm SL, Tucuruí, about 2 km below dam, 346'29.47"S 4939'9.64"W, 9 Oct 1984, G. Mendes dos Santos. ZMA 119.829, 1, 82.8 mm SL, Cametá, 0214'S, 04930'W, Jul 1985, A. Werner.

No data. AMNH 97659, 1, 82.8 mm SL.

Diagnosis. Pseudacanthicus pitanga , sp. nov., is distinguished from its congeners (except P. leopardus ) by its color pattern with intense orange to red fins (vs. dark background color with white spots in P. serratus and P. fordii or gray background color with black blotches in P. histrix and P. s pi n os u s). It can be distinguished from P. leopardus by the presence of dark blotches anostomosing to form continuous zigzag bands alongside longitudinal keels; absence of blotches on ventral surface of body; faint blotches on head and all fins with orange to red color on unbranched ray and sometimes on subsequent branched rays (dark blotches conspicuous, never anostomosed; large dark blotches on ventral surface; conspicuous dark blotches on head; and red color restricted to dorsal and caudalfin rays). Pseudacanthicus pitanga can be further diagnosed from congeners by the following combination of osteological characters: contact of sphenotic with sixth infraorbital absent ( Fig. 3 ; vs. present in remaining species), lateral surface of metapterigoid channel triangular (vs. rounded in remaining species), posterior area of contact between cleithrum and coracoid ventrally expanded (vs. straight in remaining species).

Description. Morphometric and meristic data summarized in Table 1 . Dorsal profile of body slightly convex from tip of snout to vertical through dorsal-fin origin; concave, nearly straight from that point to caudal-fin origin. Ventral profile of body straight from snout tip to caudal-fin origin. Ventral surface from tip of snout to urogenital papillae lacking plates, except for few small plates at pectoral- and pelvic-fin origins. Greatest body width at pectoral girdle. Trunk strongly keeled; five rows of keels; each one along each body plate series. Greatest body depth at dorsal-fin origin, body most slender at caudal peduncle.

Head tall, pointed anteriorly, somewhat triangular in dorsal view; snout and cheek completely covered by numerous small plates, except for small naked area on tip of snout. Snout very pointed in dorsal view. Nasal bone rectangular, thin and elongate ( Fig. 3 ). Frontal bone short, slightly contacting nares anteriorly and orbit posteriorly ( Fig. 3 ). Anterior margin of frontal short, reaching posterior margin or half nare length ( Fig. 3 ). Parietosupraoccipital enlogate, its posterior edge narrow, with V-shaped crest ( Fig. 3 ). Sphenotic short, not contacting IO6, with conspicuous odontodes ( Fig. 3 ). Orbit small to moderate in size (9,6–16,4% HL), positioned dorsolaterally. Iris with small, dorsal flap over pupil. Pterotic-supracleithum short, with few fenestrae, its anterior process contacting a small region of posterior margin of orbit. Posterior area of pterotic-supracleitrhum with one or two small sized plates. Infraorbital series with 8 pores. Infraorbital 4 widely contacting posterior margin of orbit. Infraorbital 6 associated with only the posteroventral margin of orbit. Lateral line pores restricted to hypural plate. Mouth moderate in size, nearly as long as wide. Lips large, covered with papillae; size of papillae decreasing towards posterior margin of lower lip; central buccal papilla absent or little developed. Upper lip folded over itself. Maxillary barbel short; base of barbel united to lips, with free tip. Lower lip not reaching anterior margin of coracoid. Medial end of premaxillary teeth curved inwards. Premaxillae and dentary narrow and elongate. Dentary strongly curved inwards. Teeth slightly thick, well-developed, with long crown and large lateral cusp; its distal edge slightly curved inwards. Four to five pairs of predorsal plates. Cheek plates eversible, with hypertrophied odontodes.

Dorsal-fin rays i,8, pterygiophores located posterior to neural spines of vertebral centra 6–17. Dorsal-fin base very long, its length equals to 12 dorsal plates, reaching pre-adipose plate; connected to adipose fin by thick membrane. Dorsal-fin spinelet V-shaped with locking mechanism. Eight furcate neural spines supporting dorsal fin. Pectoral and pelvic fins well developed, medial portion conspicuously expanded relative to base; distal margin rounded. Pectoral-fin rays I,6; unbranched ray covered with well-developed odontodes. Tip of adpressed pectoral fin almost reaching vertical through medial, unbranched, pelvic-fin ray. Pelvic-fin rays i,5; pelvic-fin spine reaching vertical through anal-fin base when adpressed. Anal-fin rays i,4, located posterior to haemal spines of vertebral centra 14–17. Caudal fin i,14, i, truncate; caudal fin-ray filaments present in juveniles; supracaudal plates 7. Three to five (usually four) procurrent caudal-fin rays. Total vertebrae 29, precaudal 12. Sixth rib strongly thickened, remaining ribs slender.

Color in life. Dorsal surface of trunk pale brown with median dark blotches that might be faint in juveniles and some adults; dark blotches anostomosing to form continuous zigzag bands alongside longitudinal keels in most specimens. Head without well-defined spots or blotches. Ventral surface pale, sometimes with some few faint spots in the abdominal region; spots in general absent in most specimens. All fins with orange or almost red color, at least in the unbranched fin-rays; more evident in the dorsal and caudal unbranched fin-rays. Juvenile specimens (in most cases) with dorsal and caudal fin almost completely faint orange without dark blotches.

Color in alcohol. Specimens in alcohol usually exhibit the same color pattern when live, but in most cases the orange coloration of fins and blotches on body are inconspicuous and faint.

Distribution. Pseudacanthicus pitanga probably occurs throughout the median and lower rio Tocantins. The species was recorded in the lower Tocantins river basin, at Serra dos Carajás, Tucuruí and Cametá, Pará state, and median Tocantins river basin, between São Salvador and Lajeado, Tocantins state ( Fig.4 ).

Fisheries and economic importance. Because of its flashy and beautiful color pattern, the species of Pseudacanthicus , although not formally described, are very well known by local fishermen and the aquarist community, being an economic resource in some cases. Specimens of Pseudacanthicus pitanga , like other ornamental species, are exported to several countries worldwide, especially in Europe and the U.S.A., which has enabled many aquarists to breed them (E. Bertelsen, pers. comm.). Pseudacanthicus pitanga is economically important in the aquarium trade as an ornamental fish. The ornamental fish exploration has been a common practice in lower Tocantins in the Marabá region, and P. pitanga is recognized in the L number aquarist system as L024 ( Schraml & Schaefer, 2004). Ornamental fishes are usually captured by diving with the aid of an air compressor, a collecting technique that is very common in ornamental fish exploration centers, such as in Marabá (Tocantins), Altamira (Xingu), and Santarém and Itaituba (Tapajós) (more about capture techniques in Sousa & Birindelli, 2009).

Etymology. The specific epithet pitanga derives from Tupi-Guarani, meaning red, in allusion to the color of fins. An adjective.

Figures

FIGURE 1. Holotype of Pseudacanthicus pitanga, MZUSP 34296, 220.7 mm of SL.

FIGURE 2. Color in life Pseudacanthicus pitanga, adult and juvenile aquarium specimens (Images by Erlend Bertelsen).

FIGURE 3. Dorsal view of the cranium in Pseudacanthicus pitanga, MZUSP 34295, 236.3 mm SL, IO 6 correspond to sixth infraorbital.

FIGURE 4. Distribution map of Pseudacanthicus pitanga, red circle correspond to type locality.

Tables

TABLE 1. Morphometric and meristic data of Pseudacanthicus pitanga based on 31 specimens and the holotype. SD = Standard deviation.

Character	Holotype Minimum MZUSP 34296	Maximum	Mean	SD
Standard length (SL)	220.7 86.5	300.0	165.1	-
Percent of standard length Predorsal length Head length (HL)	47.8 39.2 38.0 19.4	72.3 59.6	45.4 37.1	5.3 5.4
Bory length at dorsal-fin origin Cleithral width Thorax length	23.7 15.9 33.3 27.6 21.7 19.7	28.3 48.2 39.3	20.7 30.9 25.2	2.8 3.5 3.1
Pectoral-spine length Abdominal length Pelvic-spine length	39.4 28.3 29.1 22.3 35.5 22.8	52.1 38.9 48.6	32.7 26.3 29.5	4.5 2.9 4.4
Postanal length Anal-fin spine length Dorsal spine length	32.8 27.7 24.3 13.4 41.8 25.9	51.2 31.4 54.2	32.0 20.5 34.4	3.9 3.2 5.2
Dorsal-fin base length Caudal peduncle depth Percent of head length	26.9 23.2 16.8 12.1	46.2 22.1	28.9 14.4	3.8 1.8
Orbit diameter Snout length Internares width	9.6 9.6 62.7 58.1 16.7 10.4	16.4 69.2 18.2	13.1 63.5 14.5	1.6 3.0 2.0
Interorbital width Head depth Mouth length	36.9 29.6 59.0 43.6 41.0 33.8	38.5 60.4 50.5	33.8 52.2 42.7	2.5 5.5 3.9
Mouth width Dentary tooth cup length Premaxillary tooth cup length	39.5 14.4 9.2 4.4 4.6 2.7	48.4 11.8 9.9	39.9 8.4 4.8	6.2 1.6 1.6
Meristics Dorsal plate series Mid-dorsal plate series	25 23 23 23	26 26	Mode 25 24	- -
Median plate series Mid-ventral plate series Ventral plate series	24 23 23 22 13 11	27 26 20	25 24 17	- - -
Precaudal plates Premaxillary teeth Dentary teeth	7 6 7 4 13 6	9 10 16	8 4 13	- - -