Hypostomus delimai,

Zawadzki, Cláudio Henrique, Oliveira, Renildo Ribeiro de & Debona, Tiago, 2013, A new species of Hypostomus Lacépède, 1803 (Siluriformes: Loricariidae) from the rio Tocantins-Araguaia basin, Brazil, Neotropical Ichthyology 11 (1), pp. 73-80: 74-77

publication ID

http://doi.org/ 10.1590/S1679-62252013000100008

DOI

http://doi.org/10.5281/zenodo.5073014

persistent identifier

http://treatment.plazi.org/id/03CC87D9-2144-FF9B-FEE2-F9031C3ACF6A

treatment provided by

Carolina

scientific name

Hypostomus delimai
status

new species

Hypostomus delimai  new species ( Figs. 1- 3View FigView FigView Fig)

Holotype. INPA 6191, 235.2 mm SL, Brazil, Pará, Itupiranga , rio Tocantins, 05°07’29.6”S 49°18’44.4”W, 14 Nov 1980, INPA ichthyological staff.GoogleMaps 

Paratypes. Brazil: Pará State: ANSP 192612View Materials, 1, 202.1 mm SL; INPA  35376, 3View Materials, 162.7View Materials -230.0 mm SL. ZUEC 7088, 200.7 mm SL  ,

collected with holotype. INPA 2485View Materials, 1, 175.4 mm SL, Tucuruí, rio Tocantins, 03°51’54.1”S 49°39’1.6”W, 31 Oct 1987, F. Martinho. INPA 6153View Materials, 1, 247.2 mm SL,GoogleMaps  Itupiranga, lago Morateiro, rio Tocantins, 05°08’42.1”S 49°18’10.2”W, 4 Jul 1982,GoogleMaps  INPA ichthyological staff. INPA 6192View Materials, 2View Materials, 206.0 and 253.1 mm SL, Itupiranga, rio Tocantins, 05°09’59.5”S 49°20’1.0”W, 30 Jun 1980, INPA ichthyological staff.GoogleMaps  INPA 6193View Materials, 4View Materials, 103.9View Materials -215.0 mm SL. MPEG 24021View Materials, 1, 168.8 mm SL, Itupiranga , rio Tocantins, 05°05’26.3”S 49°20’13.9”W, 30 Jun 1980,GoogleMaps  INPA ichthyological staff. INPA 6195View Materials, 1, 147.8 mm SL, Itupiranga, rio Tocantins, 05°05’26.3”S 49°20’13.9”W, 30 Jun 1981, M. Jégu.GoogleMaps  MZUSP 110815View Materials, 1View Materials, 207.0 mm SL, São Geraldo do Araguaia , rio Gameleira , at its mouth, tributary to rio Araguaia , 06°08’11”S 48º23’35”W, 4 May 2009, T. Debona & C. H. Zawadzki.GoogleMaps  Tocantins State: INPA 20029View Materials, 1View Materials, 118.0 mm SL, Caseara, Parque Estadual do Cantão , lago Volta Grande, rio Araguaia , 09°47’16”S 50°09’54.5”W, 18 May 2000, J. Zuanon, E. J. G. Ferreira, S. Amadio & G. M. Santos.GoogleMaps  INPA 20473View Materials, 1, 167.1 mm SL, Caseara, Parque Estadual do Cantão , lago Perdidos, rio Araguaia , 09°42’59.9”S 50°08’14”W, 24 Feb 2000, J. Zuanon, E. J. G. Ferreira, S. Amadio & G. M. Santos.GoogleMaps  INPA 35376View Materials, 3View Materials, 162.7View Materials -230.0 mm SL; and NUP 11015View Materials, 1, 204.3 mm SL, border of Ananás and São Geraldo do Araguaia (in the border of the States of Tocantins and Pará), rio Araguaia , 06°08’14”S 48°19’52”W, 9 Jul 2009, T. Debona.GoogleMaps  NUP 11016View Materials, 1, 176.7 mm SL, Araguanã, rio Lontra , tributary to rio Araguaia , 06º33’56”S 48º38’11”W, 8 May 2009, T. Debona & C. H. Zawadzki.GoogleMaps  NUP 11017View Materials, 1, 205.5 mm SL, Ananás, border of the States of Tocantins and Pará, rio Araguaia , 06°08’14”S 48°19’52”W, 8 May 2009, T. Debona & C. H. ZawadzkiGoogleMaps  .

Diagnosis. The new species is distinguished from all other Hypostomus  species, with exception of H. carinatus (Steindachner, 1881)  , H. hoplonites Rapp Py-Daniel, 1988  , and H. watwata Hancock, 1828  , by the presence of five to eight (mode seven) predorsal plates limiting the posterior border of the supraoccipital bone ( Fig. 3View Fig) (vs. one to three plates). Hypostomus delimai  differs from H. carinatus  , H. hoplonites  , and H. watwata  by having pale spots against darker ground color on body and fins (vs. dark spots against lighter ground color).

Description. Based on holotype and 21 paratypes. Counts and measurements in Table 1. Head broad and slightly compressed. Body width at cleithral region slightly greater than head depth and approximately equal to head length. Snout and anterior profile of head weakly rounded in dorsal view. Snout in lateral profile rising from horizontal at approximately 45º. 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 somewhat ellipsoid in cross-section, dorsally and ventrally flattened. Eye moderate in diameter (14.1-17.1% of HL), dorsolaterally positioned. Interorbital area wide and flat in frontal view. Mesethmoid forming inconspicuous median ridge on dorsal region of snout. Weak ridge on dorsal surface of head, from nares to upper margin of eyes, and from here to compound pterotic. Cheek plates with odontodes usually small, but sometimes distinctively larger on posterior border. Cleithral process deep in lateral view, usually deeper than longer, its upper border convex. Supraoccipital generally with conspicuous median ridge; with narrow and relatively long posterior process limited by five to eight (mode seven) predorsal plates. Plates limiting supraoccipital as part of complex arrangement of platelets ( Fig. 3View Fig). Dorsal and lateral surface of head and body covered with dermal plates, except for small unplated area on tip of snout and dorsal-fin base. Predorsal region flattened, with paired moderate ridges. Trunk covered by five lateral series of dermal plates. Dorsal series of plates keeled from dorsal-fin origin to adipose-fin origin, then weakly keeled until upper procurrent caudal-fin rays. Keeled plates of all series, except ventral, with longitudinal rows of odontodes clustered at middle of plates. Mid-dorsal series with longitudinal rows of odontodes complete. Median series bearing complete lateral line, complete row of hypertrophied odontodes. Mid-ventral series moderately bent, with slightly enlarged longitudinal rows of odontodes. Ventral series strongly flattened on anterior region of caudal peduncle, bent on posterior region, and without conspicuous hypertrophied odontodes.

Mouth moderate in size with enlarged central buccal papilla; buccal papilla with distal portion usually fringed. Lips wide and round. Outer edge of upper lips with odontodes. Lower lip far from reaching gill opening, its inner surface covered with numerous small papillae, larger proximally. Maxillary barbel moderate in size, slightly shorter than orbital diameter. Teeth slender, with elongated main cusp and smaller lateral cusp. Intermandibular tooth row angle approximately from 100° to 120°.

Lower surface of head totally covered by platelets except area just beneath lower lip. Pectoral bridge and abdomen totally covered by platelets except small area at base of left and right pelvic-fin unbranched rays, respectively.

Dorsal fin II,7; moderate in size; spine flexible; its border almost straight; posteriorly reaching spine of adipose fin. Adipose-fin spine well developed, curved inward, with distal tip usually reaching anteriormost dorsal procurrent ray. Pectoral fin I,6; spine not flexible, slightly curved, with rounded tip, and usually with hypertrophied odontodes, largest on distal portion in largest specimens; when adpressed almost reaching middle of pelvic-fin spine. Pelvic fin i,5; unbranched ray curved inward; when adpressed surpassing anal-fin unbranched-ray base; its border slightly rounded. Anal fin i,4; when adpressed, distal tip of posterior rays reaching seventh or eighth plate posterior to anal-fin origin. Caudal fin i,7+7,i; slightly emarginated, with ventral lobe equal to slightly longer than dorsal lobe.

Color in alcohol. Ground color of dorsal surface of head and body grayish-brown. Head, dorsum and flanks covered with many pale spots against darker background. Pale spots dense, small, close to each other and less numerous, larger and more distant to each other from compound pterotic to caudal peduncle ( Figs. 2View Fig and 4View Fig). On flanks of some individuals pale spots with irregular format usually fused to each other, sometimes forming vermiculations ( Fig. 1View Fig). Ventral region of head and abdomen slightly lighter than dorsal region in specimens up to 100.0 mm SL, in larger specimens ventral region of body similar to dorsal region. Some larger specimens with upper and lower lip dark. Dorsal, pectoral, pelvic, anal and caudal fins dark brown with pale round spots mainly over rays. Adipose fin dark brown with pale spots sometimes fused along spine ( Figs. 1View Fig and 5View Fig).

Color in life. Color pattern similar to that observed in preserved specimens, except body and fins exhibiting greenbrown background and tan spots with green tinge ( Fig. 2View Fig).

Distribution and habitat. The species was found only in middle stretches of the rio Tocantins-Araguaia basin ( Fig. 4View Fig). Records of the new species were done before the construction of Tucuruí dam in the rio Tocantins and in the rio Araguaia, in a habitat that soon will be flooded by the construction of the Santa Isabel dam. The rio Araguaia has about 2,627 km long, and its headwaters are located near the Emas National Park, southeast of the Goiás State, Brazil. The rio Araguaia flows northeast to a junction with the rio Tocantins near the town of São João do Araguaia in the State of Pará. These rivers have turbid water, rocky and sandy substrate, and variable remnant riparian vegetation. The new species was found cooccurring, with Squaliforma cf. emarginata (Valenciennes, 1840)  , Hypostomus faveolus  , Hypostomus cf. plecostomus (Linnaeus, 1758)  , H. pyrineusi (Miranda Ribeiro, 1920)  , and another putative undescribed species of Hypostomus  .

Etymology. The specific epithet delimai  is in honor of Flávio César Thadeo de Lima, Brazilian ichthyologist, due to his numerous contributions to Neotropical ichthyology.

INPA

Instituto Nacional de Pesquisas da Amazonia