Spectracanthicus zuanoni, Chamon & Rapp Py-Daniel, 2014

Chamon, Carine C. & Rapp Py-Daniel, Lúcia H., 2014, Taxonomic revision of Spectracanthicus Nijssen & Isbrücker (Loricariidae: Hypostominae: Ancistrini), with description of three new species, Neotropical Ichthyology 12 (1), pp. 1-25 : 19-22

Spectracanthicus zuanoni , new species Figs. 14-15

Oligancistrus sp. - Werner et al., 2005: 23 [catalog; picture]. Oligancistrus n. sp. 2. - Camargo et al., 2012: 131 [catalog;

picture].

Holotype. INPA 25874, 122.4 mm SL, ilha do Sr. Izaltino , rio Xingu, Altamira, Pará, Brazil, 3°16’21”S 52°12’7”W, J. Zuanon, 14 Sep 1997.

Paratypes. All from Brazil, Pará, rio Xingu. INPA 4031 , 2 , 78.2- 127.9 mm SL, 1°30’0”S 51°53’0”W, 05 Oct 1990 , L. Rapp Py-Daniel & J. Zuanon. INPA 4147 , 1 , 84.9 mm SL, ilha de Babaquara , 1°30’0”S 51°53’0”W, 05 Oct 1990, J. Zuanon. INPA 25874 , 3 , 69.9-126.2 mm SL, ilha do Sr. Izaltino , bedrock beside the island (left margim) , 1°30’0”S 51°53’0”W, 14 Sep 1997, J. Zuanon. INPA 25876 , 1, 123.1 mm SL, 1°30’0”S 51°53’0”W. INPA 25877 , 2 , 70.6-129.3 mm SL, ilha do Sr. Izaltino , left margin , 1°30’0”S 51°53’0”W, 14 Sep 1997, J. Zuanon. INPA 25878 , 1, 107.3 mm SL, 1°30’0”S 51°53’0”W. INPA 25879 , 2 , 76.9-112.8 mm SL, ilha do Sr. Izaltino , bedrock beside the island (left margim) , 1°30’0”S 51°53’0”W, 14 Sep 1997, J. Zuanon. INPA 25881 , 1 , 93.2 mm SL, ilha do Bananal , Senador José Porfírio, 08 Sep 1997, J. Zuanon. INPA 25882 , 2 , 55.9-82.8 mm SL, corredeiras do Arini, 1°30’0”S, 51°53’0”W, 07 Sep 1997, J. Zuanon. MZUSP 107200 , 3 , 59.4-86.1 mm SL, bedrock near Jericoá , near Mucura fall and above Mazinho’s farm, Altamira , 3°24’52”S 51°44’23”W, 07 Jun 2010, Equipe ECIX (O. T. Oyakawa, J. Muriel-Cunha, C. C. Chamon, I. Fichberg, L. Rossi & A. Sawakushi) . MZUSP 107202 , 3 , 37.8-95.3 mm SL, Gorgulho da Rita , Altamira , 3°20’26”S 52°11’4”W, 06 Jul 2010, Equipe ECIX. MZUSP 107207 , 17 , 41.3-98.1 mm SL, ilha de Babaquara , bedrock, Altamira , 3°24’10”S 52°12’27”W, 06 Jul 2010, Equipe ECIX .

Non-Types. All from Brazil, Pará, rio Xingu. INPA 3957 , 5 , 20.1-58.8 mm SL, cachoeira de Baituká , 1°30’0”S 51°53’0”W, 09 Oct 1990, L. Rapp Py-Daniel & J. Zuanon . INPA 3966 , 2 , 67.1- 96.6 mm SL, Praia do Pedral , 1°30’0”S 51°53’0”W 07 Oct 1990, L. Rapp Py-Daniel & J. Zuanon . INPA 28545 , 2 , 27.5 - 23.8 mm SL, Costa do Junior , 03°29’28”S 52°19’07”W, 23 Sep 1997, J. A. Zuanon . INPA 31411 , 4 , 78.4-92.9 mm SL, bedrock in front of the River, Comunidade do Maia , 03°30’44”S 51°44’43”W, 09 Nov 2008, L. Rapp Py-Daniel et al . INPA 31422 , 3 , 59.3-111.3 mm SL, cachoeira do Landi , 03°35’01”S 51°49’21”W, 08 Nov 2008, L. Rapp Py-Daniel et al . INPA 31454 , 2 , 47.6-71.1 mm SL, Gorgulho da Rita , 03°20’14”S 52°11’18”W, 07 Nov 2008, L. Rapp Py-Daniel et al . INPA 31455 , 6 , 41.4-72.4 mm SL, Babaquara , 03°23’45”S 52°12’16”W, 07 Nov 2008, L. Rapp Py-Daniel et al . INPA 31460 , 8 , 35.3-89.8 mm SL, Itaboinha, bedrock, Vitória do Xingu , 03°53’22”S 51°56’26”W, 04 Nov 2008, L. Rapp Py-Daniel et al . INPA 31480 , 11 , 53.1-126.8 mm SL, Arroz Cru , 03°25’20”S 51°57’22”W, 06 Nov 2008, L. Rapp Py-Daniel et al . INPA 31775 , 1 , 113.0 mm SL, ilha do Davi, Altamira , 03°32’39”S 51°57’29”W, 01 Nov 2008, L. Rapp Py-Daniel et al . INPA 31794 , 2 , 50.5 -54.0 mm SL, Belo Monte , 03°06’54”S 51°43’15”W, 05 Nov 2008, L. Rapp Py-Daniel et al . MHNG 2578.027 , 1 , 81.8 mm SL, Altamira (?), imported from Belém, D. Fisher . MHNG 2.680 .014, 1, 79.9 mm SL, aquarium import , R. Covain . MHNG 2684.026 , 2 , 62.2-66.6 mm SL, aquarium import , R. Covain .

Diagnosis. Spectracanthicus zuanoni can be diagnosed from all other congeners by its color pattern consisting of large, white spots (vs. small yellowish dots in S. murinus , S. punctatissimus , and S. tocantinensis , and dark gray lacking dots in S. immaculatus ). It also differs from congeners, except S. murinus , by the larger orbital diameter (up to 29.2% of HL vs. up to 25.7% in S. punctatissimus , 20.3% in S. tocantinensis , 16.2% in S. immaculatus ). It further differs from S. murinus by the rounded dorsal view of the snout, the bar-shaped, eversible opercle with conspicuous odontodes, and the presence of four unbranched anal-fin rays (vs. snout slightly pointed; opercle triangle-shaped, not eversible, lacking conspicuous odontodes; three anal-fin unbranched rays). From S. tocantinensis it differs by present high counts of dentary teeth (19-43 vs. 8-16) and by IO4 forming just a small area of orbit (vs. IO4 forming posterior edge of orbit almost totally).

Description. Morphometric and meristic data summarized in Table 5 . Dorsal profile of body slightly convex from tip of snout to vertical through of dorsal fin; concave, nearly straight from that point to caudal-fin origin. Ventral profile straight from snout tip to origin of caudal fin. Ventral surface from tip of snout to urogenital papillae lacking plates, except for few small plates at pectoral and pelvic-fins origins. Body deep and robust even at caudal peduncle. Head and trunk lacking keels or ridges. Greatest body depth at dorsal-fin origin; lowest at caudal peduncle.

Head wide, convex dorsally; snout and cheeks completely covered by numerous small plates, except for small naked area on tip of snout. Snout slightly rounded in dorsal profile. Nasal elongated, L-shaped. Frontal short with a slight contact with nares anteriorly and orbit posteriorly. Anterior margin of frontal short, reaching posterior margin or half of length of nare. Parieto-supraoccipital short with posterior edge narrow, lacking crest. Sphenotic short, without contact with IO6, lacking conspicuous odontodes. Orbit enlarged (16.6-29.2% HL), placed dorsolaterally in head. Iris with small dorsal flap over pupil. Pterotic-supracleithrum short with few fenestrae; anterior process forming most posterior margin of orbit. Posterior area of pterotic-supracleithrum with one 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. 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 series almost straight. Premaxillae and dentaries narrow and elongate. Dentaries strongly curved inwards. Teeth medium size, well developed, slender, with long crown and large lateral cusp. Distal edge of teeth slightly curved inward. Eversible cheek plates with associated hypertrophied odontodes and disposed as unique block connected to opercle, that can be everted to approximately 90 o from head by opercle movements.

Body covered by five longitudinal series of plates supporting odontodes. Keels absent. Three to four predorsal plates; some small azygous predorsal plates sometimes present. Eight neural bifid spines supporting dorsal fin. Dorsalfin rays i,7, located posterior to neural spines of vertebral centra 6-17. Dorsal-fin base very long, its length equivalent to 12 dorsal plates, reaching pre-adipose plate and connected to adipose fin by thick membrane. Dorsal-fin spinelet V-shaped with lock mechanism. Pectoral and pelvic fins well developed, medial portion much expanded relative to base; distal margins rounded. Pectoral-fin rays i,6; unbranched ray covered with conspicuous 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 hemal spines of vertebral centra 15-17. Caudal-fin rays i,14,i, truncated; supracaudal plates. Five to six procurrent caudal-fin rays. Caudal peduncle strongly deep in lateral view. Total vertebrae 26, precaudal 8-12. Sixth rib strongly thickened, remaining ribs slender. Infraorbital with 7-8 pores. Infraorbital 4 with little contact with orbit by posterior margin. Infraorbital 6 formed just postero-vental part of orbit. Lateral line pores restrict to hypural plate.

Color in alcohol. Dorsal surface of body and fins evenly brown covered by large white spots. Spots more frequent and conspicuous in dorsal and caudal fins than in pectoral, pelvic and anal fins. Some specimens, especially juveniles, can present overlapped spots forming smudges. Head poorly spotted, some individuals can present vermicular bands near snout region. Abdomen region ochre without spots.

Geographic distribution. Spectracanthicus zuanoni is known from the rio Xingu basin, near Altamira and Belo Monte, Pará State, Brazil ( Fig. 5 ).

Etymology. The specific epithet is in honor to Jansen Zuanon (INPA) due to his contribution to the knowledge of Neotropical Ichthyology. Jansen Zuanon was also the first ichthyologist who collected and identified this species as a new one.

Fishery and economical importance. Spectracanthicus zuanoni is also recognized as “acari bola branca”, L020 and

L354 (L-number; Schraml & Schafer, 2004) by aquarists and local fishermen. As in Itaituba and Santarém, at rio Tapajós, Altamira is also known for its ornamental fishery activities.

Ecological notes. Spectracanthicus zuanoni is a nocturnal species that feeds on algae and other food items off periphyton by grazing over rock bottom.According to Zuanon (1999) and Rapp Py-Daniel & Zuanon (2005), Spectracanthicus zuanoni is a moderate reophilic species that is found in rock-bottom areas subjected to backwater and strong currents. Specimens were found individually or in groups of three, under shelter boulders (adults) and spaces beneath rocks (juveniles), up to 2m deep. The juveniles share the shelters with other loricariids such as Ancistrus sp., A. ranunculus , Baryancistrus xanthellus , Spectracanthicus punctatissimus , Hopliancistrus tricornis , Parancistrus nudiventris , Peckoltia vittata , and Pseudancistrus aff. barbatus .

Figures

Fig. 14. Spectracanthicus zuanoni, holotype, INPA 25874, 122.5 mm SL, rio Xingu, Pará State, Brazil.

Fig. 15. Color in live of Spectracanthicus zuanoni. Image by J. Birindelli.

Fig. 5. Distribution map for the species of Spectracanthicus. Circles, S. murinus; stars, S. punctatissimus; squares, S. immaculatus; triangle, S. tocantinensis and diamon, S. zuanoni. White symbols refers to type locality.