Harttia merevari , a new species of catfish ( Siluriformes : Loricariidae ) from Venezuela

Harttia merevari, a new species of loricariid catfish, is described from eight specimens captured in the upper Caura River, Orinoco River basin, Venezuela. The new species is recognized by the following combination of characters: abdomen naked; two or three preanal plates; a bony plate before each branchial opening; seven lateral plates between the pectoral and pelvic fins; maxillary barbel short and attached to the oral disk by a fleshy fold; head dorsal surface and anterior portion of the body light or dark yellow with numerous, round black spots; posterior region of the body light or dark yellow with five black transverse bands, dorsal central area of the two anterior bands diffused. The discovery of this new species extends the distribution of the genus northwest to include the Orinoco River basin on the northern slope of the Guyana shield.

In this paper Harttia merevari is described from the upper Caura River, Bolívar State, Venezuela.The presence of this new species of Harttia in the Venezuelan portion of the Guyana Shield elevates the number of Harttia species to 22, and increases the northwestern geographic distribution boundary for the genus.

Materials and Methods
The specimens used in this work are deposited at the following ichthyological collections: Museo de Biología de la Universidad Central de Venezuela, Colección de Peces (MBUCV-V) and Field Museum of Natural History (FMNH).Measurements and counts are those described by Boeseman (1971).The measurements were taken with a digital caliper.Counts, observations, and drawings of external morphology were done using a stereoscopic microscope.Comparisons of external morphology and morphometric and meristic data were carried out using original descriptions plus specimens of Harttia from FMNH and specimens of H. platystoma and H. guianensis deposited at MBUCV.

Harttia merevari, new species
Figs  flap.Triangular plate anterior to each branchial opening, ornamented with small odontodes.Abdomen naked.Preanal region with two or three well developed plates (Fig. 2).Small specimens with two rectangular or square preanal plates preceded by one to seven small, irregularly shaped plates, in irregular arrangement.Holotype with three well defined preanal plates: middle triangular plate with apex directed to anus; sided by two large and rectangular plates.Each lateral preanal plate preceded by single, small, square plate (Fig. 2) Six or seven plates between pectoral and pelvic fins.30 or 31 lateral plates.Anterior lateral plates carinate, forming double keel until plate 17 or 18, after which plates unite to form single keel to base of the caudal fin.Dorsal fin I,7 Pectoral fin I,6 Pelvic fin I,5.Anal fin I,5 Caudal fin i,12,i.
Coloration.Dorsal region of head and anterior part of body light or dark yellow with many black spots.Posterior region of body light or dark yellow with five transverse black bands; first two bands with diffused central portion (Fig. 1).Ventral region of head and body whitish.Dorsal, pectoral and pelvic fins with rectangular or square black blotches on rays; interradial membranes hyaline.Dorsal, pectoral and pelvic fin spines with four, five and four black blotches, respectively.Anal fin uniform whitish or yellow.Caudal fin with four black blotches on rays, and two transverse black bands.Anterior transverse band wide and well defined near base of middle rays; posterior band thin and weakly defined.Distal border of caudal fin hyaline Habitat.Harttia merevari was captured very close to the top of Salto Pará (Fig. 3), a 50 m fall that separates the Caura River into upper and lower faunal sections (Chernoff et al., 2003).
The specimens were captured on and among relatively large rocks with flat surfaces, very near shore.The water was transparent with flow from fast to very fast.Podostemataceas were growing on the rocks.The depth at the colleting site was 1.5 meters on average.

Etymology.
The species-group name, merevari, is the Ye-kuana name for the Caura River, and is treated here as a noun in apposition.
Comparisons.The largest known specimen of H. merevari is 99.4 mm SL and this specimen as well as all other paratypes, which are smaller, have a naked abdomen.There is no evidence of plate development over the abdomen.The lack of  (Oyakawa, 1993;Langeani et al., 2001).In juveniles of H. torrenticola preanal plates are absent, adults have preanal plates but they are circular in shape, sparse, and reduced in number from 2 to 4 (Oyakawa, 1993).Harttia gracilis and H. loricariformis have two trapezoidal preanal plates, and 3 or 4 small plates anterior to those (Steindachner, 1877;Oyakawa, 1993).Additionally, H. leiopleura and H. novalimensis lack a bony plate in front of the gill opening; H. garavelloi does not have a maxillary barbel; and H. leiopleura does not have lateral plates between the pectoral and pelvic fins (Oyakawa, 1993)   Geographic Distribution.Harttia species are primarily distributed in the Amazon River basin and southeastern Brazil, but a few including the new species are found in the Guianas and the Orinoco River basin (Table 1).Harttia merevari extends the northwestern distribution of the genus to the northwestern slope of the Guyana shield draining into the Orinoco basin, being the first species to be recorded in this area (Fig. 3).If we consider the genus Cteniloricaria as a synonym of Harttia as proposed by Rapp Py- Daniel & Oliveira (2001), the number of species assigned to Harttia reaches 22 species.Along the Guyana Shield, Harttia species are found in rivers in Suriname (Suriname River), French Guiana (Approuague and Sinnamary rivers) and Venezuela (Caura River and Cuyuni -Essequibo River drainage) draining the northern slope of the shield, and the Trombetas and Uatumã watersheds draining the southern slope of the Guyana Shield in Brazil (Boeseman, 1971;Machado-Allison et al., 2000;Rapp Py-Daniel & Oliveira, 2001) Further south, species have been reported from the Tapajós and Tocantins River basins on the northern slope of the Brazilian Shield (Rapp Py-Daniel & Oliveira, 2001), São Francisco basin, upper Paraná and coastal drainages of southeastern Brazil (Steindachner, 1877;A. Miranda Ribeiro, 1908;P. Miranda Ribeiro, 1939;Oyakawa, 1993;Langeani et al., 2001) There is no particular distributional pattern among the species with or without naked abdomens; representatives of both groups are found along the Guyana shield and the southeastern region of Brazil.

Fig. 2 .
Fig. 2. Harttia merevari, MBUCV-V-26578, holotype, 99.4 mm SL.Ventral region showing the shape, relative size and/or arrangement of bony plates in front of the gill opening, between pectoral and pelvic fins, and preanal area.

Fig. 3 .
Fig. 3. Map of the Orinoco River drainage showing the type locality (solid circle) of Harttia merevari.
Description.Morphometric data presented in Table2.Head and body depressed.In dorsal view, body slender (

Table 1 .
List of the species of the genus Harttia, geographic distribution and abdomen type (1 -a stripe of tiny plates before the pelvic fins; 2 -three to five small plates at the scapular girdle level).

Table 2 .
Morphometric data of Harttia merevari expressed as percent of SL (n=8).abdominal plates places H. merevari into a group of species of Harttia with naked abdomens: H. carvalhoi, H. depressa, H. garavelloi, H. gracilis, H. guianensis, H. kronei, H. leiopleura, H. loricariformis, H. novalimensis, and H. torrenticola.Harttia uatumensis probably should be considered a member of this group because this species possesses a single small patch of plates over the abdomen.Harttia carvalhoi, H. garavelloi, H. kronei, H. leiopleura, and H. novalimensis differ from H. merevari because each lacks the preanal plates present in the new species