A new dark-dotted species of Hypostomus Lacépède ( Siluriformes : Loricariidae ) from rio Paraguaçu , Bahia State , Brazil

A new species of Hypostomus Lacépède is described from the rio Paraguaçu basin, Bahia State, Brazil. The new species is distinguished from its congeners by having black and conspicuous dots on a pale background, which are similar in size on the head, trunk, and fins, along with ventral surface of head and abdomen naked or the latter plated exclusively on its anterior portion, absence of ridges on head and trunk, and caudal-fin lobes relatively similar in length. The new species further differs from the sympatric H. chrysostiktos by having seven branched dorsal-fin rays instead of 10-11 and represents the eleventh siluriform species endemic to the rio Paraguaçu basin.


Introduction
Hypostomus Lacépède is the second most species-rich genus of the Siluriformes (Ferraris, 2007), comprising about 130 valid species (Garavello et al., 2012;Zawadzki et al., 2012).Ten species of Hypostomus are reported from Brazilian northeastern coastal drainages and eight are known to occur in the rio São Francisco basin, the largest drainage in the region.Four species of the former group were described in the State of Bahia: Hypostomus brevicauda (Günther, 1864) and H. wuchereri (Günther, 1864), both with the vague type locality stated as "Bahia", Hypostomus unae (Steindachner, 1878) from rio Una, and the recently described H. chrysostiktos Birindelli, Lima & Zanata, 2007, endemic to the rio Paraguaçu basin.The first three of those species were described from material sent to the Natural History Museum, London, by Otto Wucherer, who most likely collected the specimens in coastal river basins south of Salvador (the Capital of the State of Bahia), as suggested by the type localities of reptiles also collected by him in the cities of Canavieiras, Nazaré, and Ilhéus (Günther, 1861(Günther, , 1863;;Wucherer, 1861aWucherer, , 1861bWucherer, , 1863aWucherer, , 1863b)).
Particularly for Hypostomus unae, its type locality could have been one of the three distinct small coastal drainages, all named rio Una: one that drains to the coastal city of Valença, within the Recôncavo Sul basin, another that drains to the city of Una, in the south of Bahia State, and the third possibility represented by a tributary of rio Paraguaçu, on a more central portion of Bahia.The imprecise type locality, allied to the somewhat vague description, and absence of a precise diagnosis of these three species, has rendered it difficult to precisely identify Hypostomus specimens of the coastal Brazilian drainages, particularly those from Bahia State.The six remaining northeastern species of Hypostomus were described from drainages situated relatively far north of Bahia State.Among those species, H. papariae (Fowler, 1941) was described from the lago Papari, and H. pusarum (Starks, 1913) was described from the Ceará-Mirim, both in Rio Grande do Norte State.This last species has been erroneously attributed to Ceará State in the literature (e.g., Carvalho & Bockmann, 2007).The four other northeastern species from Ceará State are H. carvalhoi (Miranda Ribeiro, 1937) from rio Granjeiro, H. eptingi (Fowler, 1941) from Fortaleza, H. jaguribensis (Fowler, 1915) from rio Jaguaribe, and H. nudiventris (Fowler, 1941) from rio Choró.
Eight species of Hypostomus are known from the rio São Francisco basin and could possibly occur in rivers draining into northeastern Brazilian coastal drainages.These are H. alatus Castelnau, 1855, H. francisci (Lütken, 1874), H. garmani (Regan, 1904), H. johnii (Steindachner, 1877), H. lima (Lütken, 1874), H. macrops (Eigenmann & Eigenmann, 1888), H. subcarinatus Castelnau, 1855, andH. vaillanti (Steindachner, 1877).Most of those species were originally described from the rio das Velhas, a tributary to the upper rio São Francisco, but they were not recorded in coastal drainages of the Bahia State.In fact, a detailed comparative study is necessary to establish exactly which of these species occurs in the portion of the rio São Francisco draining Bahia.In addition to the aforementioned species, only H. scabriceps (Eigenmann & Eigenmann, 1888) is known to occur in nearby coastal drainages (rio São Mateus, Espírito Santo State).
Expeditions carried out in the last six years in all coastal drainages of Bahia, Brazil, gathered a number of specimens of Hypostomus.Detailed examination of that material has allowed the resolution of some of the alpha-taxonomy problems of the genus in that part of the country.A new species of Hypostomus, apparently endemic to the rio Paraguaçu basin, is described herein.Boeseman (1968), Armbruster & Page (1996), Bockmann & Ribeiro (2003), and Hollanda Carvalho & Weber (2004), with the inclusion of the following measurements: anal-fin spine length, measured from insertion to tip of the first ray; anal-fin base length; body depth at dorsal-fin origin; mouth width, taken at the level of maxillary-barbel insertions; premaxillaryramus length, measured at the largest portions of the dentary complex sensu Adriaens et al. (2009, fig. 1b, 1c, 3e); and maxillary-barbel length, taken from the free outer portion of barbel.Plate counts and nomenclature follow Schaefer (1997), with modifications by Oyakawa et al. (2005).The following additions to plate counts were also used: paired dorsal plates between the last dorsal-fin ray base and adipose-fin (not including the pre-adipose plate); and ventral plates between the last anal-fin ray base and lower caudal-fin unbranched ray, not including the plate at the base of the rays.Standard length (SL) is expressed in mm and all other measurements are expressed as percents of standard length, with the exception of subunits of the head, which are expressed as percents of head length (HL).Measurements and counts were taken on the left side of the specimens whenever possible.Meristic data are given in the description.Asterisks indicate counts of the holotype, and the frequency of each count is given in parentheses.Counts of branchiostegal rays, vertebrae, and the relative position of dorsal and anal fins in relation to the vertebral column were examined only in cleared and stained specimens (c&s), which were prepared according to Taylor & van Dyke (1985).Osteological terminology follows Schaefer (1987).In the list of specimens examined, the total number of specimens and the size range is followed by the number and size range of the measured specimens (in parentheses), if different.All of the examined specimens are alcohol preserved, except when indicated as c&s.from half to approximately one eye diameter (vs.dots smaller than the pupil), interradial membranes of anteriormost dorsalfin rays with one series of dots (vs.membranes with two or three series of dots), ventral surface of body comparatively weakly covered by plates, with coverage when present restricted to anterior portion of abdomen (vs.ventral surface almost or completely covered by plates, including the central area between pelvic fins).The new species differs from H.

Methodology and terminology follow
unae by having conspicuous dots on head, trunk, and fins similar in size (vs.dots on lateral of trunk inconspicuous and, when visible, much larger than those on the head and fins), pectoral spine not distinctly strong with a few elongated odontodes on its distal third (vs.pectoral spine distinctly strong with many elongated and curved odontodes on its distal half); longer dorsal fin, with tip of last ray, usually reaching preadipose plate or adipose spine when adpressed (adpressed fin 36.6-44.3% vs.   approximately two-thirds of ventral surface of head, its posterior border not reaching transverse line between gill openings, and without distinctly fringed edges.Inner surface of lips covered by papillae, except for smooth region just behind toothed portions.Anteriormost papillae of upper lip roundish and small, followed by patch of larger and closely positioned papillae; anteriormost papillae of lower lip roundish and relatively large, followed by patch of laterally elongated papillae; distal margins of lips with band of very small papillae, more evident on upper lip.Papillae on lower lip slightly more spaced than on upper.Teeth long, bicuspid, and curved inward distally; mesial cusp longer, approximately 2.5 to 3.0 times length of lateral cusp and curved inward, similar to Hypostomus auroguttatus (Muller & Weber, 1992: fig. 2e).Most teeth overlap each other laterally.Premaxilla with 47-86 teeth (mode 70, holotype 67), dentary with 50 to 81 (mode 75, holotype 75).Contralateral premaxillary teeth forming relatively straight line or slightly concave arch; contralateral dentaries forming concave arch facing mouth cavity in angle of approximately 120°.Maxillary barbel short, usually similar in length to orbital diameter.
Body covered with five lateral rows of moderately spinulose dermal plates.Cheeks, snout, and rostrum completely plated, except for naked area on snout tip that continues ventrally to margin of upper lip and small areas around nares.Ornamentation of compound pterotic usually similar to remaining surface of head, but with odontodes slightly larger and more sparsely distributed.Opercle weakly armed, varying from covered with relatively small odontodes similar in size with those in nearby areas to with slightly more elongated odontodes on posterior portion of opercle.Posterior portion of preopercle surface with somewhat stronger odontodes.Cheek plates slightly evertible.Dorsal-fin base naked.Median series of plates bearing lateral-line canal.Dorsal series of plates starting posteriorly, at vertical through dorsal-fin origin; flattened between end of dorsal-fin base and adipose-fin spine.Ventral series of plates usually starting at origin or slightly posterior to origin of pelvic-fin base.Twenty one (26)* or 22(1) dorsal plates, 24(25)* or 25*(2) mid-dorsal plates, 25(7)* or 26(20) median plates, 25(3)* or 26(24) mid-ventral plates, 21(19)* or 22(8) ventral plates, 13(13) or 14( 14)* plates between anal and caudal fins.Three predorsal plates (two specimens with small central plate between first two plates), 7(12)* or 8(15) plates below dorsal-fin base, 5(17) or 6(10)* paired plates between dorsal and adipose fins.One (20)*, 2(6) or 3(1) preadipose plates.Aligned odontodes on plates covering most of lateral portion of trunk, forming parallel rows usually more conspicuous on posterior half of body; odontodes somewhat stronger on borders of plates of mid-ventral and ventral series.Plates without ridges, except for anterior four plates of mid-ventral series and on plates of dorsal series along dorsal-fin base to adipose fin (specimen of 68.8 mm SL without ridge on dorsal series of plates).Odontodes on head usually smaller than those on trunk and not forming rows.
Ventral surface of head and abdomen with variation on plated areas; head usually with rounded patches of plates on each side, close to branchial aperture, separated by naked central area behind lower lip; some specimens with those lateral patches reduced to few small platelets; one specimen with plates completely covering ventral surface of head, except area close to lower lip border.Anterior portion of abdomen varying from almost completely naked, with few small plates on central portion between pectoral fins, to having relatively large areas covered by plates on coracoids, central, and lateral portions close to pectoral-fin base and extending shortly posterior to it; when covered, shape of central plated area on anterior portion of abdomen rounded or roughly triangular, pointed posteriorly.Variation on anterior portion of abdomen covering apparently ontogenetic, with an almost complete lack of plates in this region in specimens up to about 110.0 mm SL, but some specimens up to 170.0 mm SL with similar condition.Posterior portion of abdomen naked; rarely with few sparse platelets on central area between pelvic-fin bases.First anal-fin pterygiophore not covered by skin in specimens about 100.0 mm SL or larger (smaller specimens with few odontodes or plate completely covered with skin).Dorsal fin II,7, its origin situated on vertical anterior to pelvic-fin origin and approximately on midlenght of pectoral-

Color in alcohol.
Overall ground color of dorsal and lateral surface of body yellowish to light brown.Dorsal and lateral surface of body covered with large black, conspicuous, and equally distributed dots.Dots on trunk usually varying from half to approximately an eye diameter, decreasing gradually in size towards head.Diameter of dots on head usually about half eye diameter, slightly smaller on snout.Fins covered with similar dots, slightly smaller than the ones on trunk and slightly larger than most dots on head.Interradial membranes of anteriormost dorsal-fin rays with one series of dots and posteriormost interradial membranes with two series; few specimens with two or three dots elongated and merged with each other, forming short longitudinal or inclined bands; membrane between longest rays with seven to nine dots, and membrane between last two rays with vertical line of four or five dots in specimens around 80.0 mm SL or larger; number of dots on membranes sometimes lower in smaller specimens.Pectoral and pelvic fins similarly dotted, but dots not fused and not forming bands; spines usually with seven or more dots in specimens around 80.0 mm SL or larger, and four or five on smaller.Adipose spine with three dots; adipose membrane dotted or plain.Caudal fin with dots on rays and membranes, usually not forming vertical stripes, but in some specimens (usually small ones) dots somewhat merged to each other forming weakly defined vertical stripes; appearance of vertical stripes observed also in some specimens when caudal fin somewhat folded.Around 10 dots on unbranched caudal-fin rays and eight or more on the longest branched rays.Anal fin dotted.All fins with posterior margins darkened.
Overall ground color of ventral body surface yellowish or light brown; black round dots usually absent, when present concentrated on head, on plated portion, or sparsely distributed on belly.Dots on belly, when present, less conspicuous than on lateral portion of body.Ventral surface of caudal peduncle yellowish, usually without conspicuous dots, with darkened median longitudinal stripe or few sparse darkened roundish areas.Largest specimen examined darker overall, with somewhat grayish background and dots slightly less visible, although with pattern described above.
Color in life.Description based on field observations of several specimens and on pictures of living specimens (Fig. 2).Ground color light brown or yellowish with somewhat golden hue.Black, round, and conspicuous dots on body and fin rays and interradial membranes similar to coloration in alcohol-preserved specimens.Ventral surface of head and abdomen yellowish to light brown, with or without dots.
Etymology.From îagûara in the indigenous language Tupi-Guarani, which means panther, in allusion to the black dotted color pattern on a clear background.A noun in apposition.
Distribution.The new species is known from the rio Paraguaçu basin (Fig. 3), an independent coastal drainage in northeastern Brazil situated on the eastern slopes of the Chapada Diamantina, Bahia State.
Habitat notes.Specimens of Hypostomus jaguar were captured in the rio Paraguaçu and its tributaries, in stretches of up to 60 m wide and 1.5 m deep, with rocky bottom, dark colored water, mild to fast water current, and at altitudes ranging from 143 to 350 meters above sea level.The riparian vegetation of the rio Paraguaçu basin is highly variable, including domains such as "Campo Rupestre", "Caatinga", "Cerrado" (Brazilian savannas) and semi-deciduous seasonal to evergreen forests.The habitats in most areas sampled were anthropized mainly due to cattle ranches.The species occurs sympatrically with Hypostomus chrysostiktos.
Remarks.In addition to the overall well-defined large dotted color pattern of Hypostomus jaguar, contrasting with the small to moderate sized and usually faded dots on body and fins coloration of the northeastern non-Bahian congeners (H. carvalhoi, H. eptingi, H. jaguribensis, H. nudiventris, H. papariae, H. pusarum), it also differs by having the ventral surface of body naked or weakly plated, always without a broad plated area on posterior portion of abdomen (vs.broad plated area on anterior and posterior portion of abdomen of H. eptingi, and anterior portion of abdomen completely covered by small plates forming a broad rectangular area continuing posteriorly through a narrow median longitudinal band, followed by a somewhat broad plated area situated in the region posterior to pelvicfin base in H. carvalhoi, H. jaguribensis, H. papariae, and H. pusarum).Hypostomus jaguar differs further from the last four species by the absence of ridges on trunk (vs.presence).The absence of dark bands on the caudal fin further distinguishes H. jaguar from H. eptingi and H. nudiventris, with five transverse dark bands on the former species and seven on the latter.The new species also differs from H. eptingi by having the lobes of the caudal fin relatively similar in length (vs.lower lobe distinctly longer than upper) and from H. nudiventris by its dorsal-fin interradial membrane coloration (absence of brown median vertical short lines or streaks parallel to rays vs. its presence).
Eight species of Hypostomus are known from the rio São Francisco basin (H. alatus, H. francisci, H. garmani, H. johnii, H. lima, H. macrops, H. subcarinatus, and H. vaillanti).As previously noted above, none of these species have so far been recorded in the coastal rivers of the Bahia State and none of them were identified among specimens collected in the rio Paraguaçu basin examined in this study.All of the Hypostomus species described from the rio São Francisco basin have the ventral surface of the head and trunk almost or completely covered by plates, in contrast to a naked or weakly covered ventral surface of the belly in the species described herein.In addition, H. jaguar is readily distinguished from H. alatus and H. francisci by having dark dots against a yellowish or clear brown background (vs.light spots against a dark background), from H. johnii and H. vaillanti by having caudal-fin lobes relatively similar in length (vs.lower lobe distinctly longer than upper), from H. subcarinatus by having a robust body and absence of predorsal ridges (vs.elongate body and at least three predorsal ridges), from H. macrops by having the pectoral spine weakly armed with odontodes (vs.pectoral spine with large and curved odontodes on most of its extension), and from H. lima by having dots similar in size along the head and trunk (vs.spots on the trunk twice as large as those on the head).From H. scabriceps, the only congener known from coastal drainages nearby, to the south of Bahia State, the new species can be further distinguished by having one or two dots covering each body plate (vs.comparatively small dots, up to four dots per plate) and dorsal fin reaching to or almost reaching to the adipose fin (vs.dorsal fin distant by at least two plates from the adipose fin).
In addition, compared with other congeners, H. jaguar can be distinguished from species of the H. cochliodon group, with the exception of H. hemicochliodon, by having bifid non-spoon-shaped teeth and the mesial and lateral cusps not being fused (vs.spoon-shaped teeth with mesial and lateral cusps usually fused).Hypostomus jaguar can be distinguished from H. alatus, H. albopunctatus, H. faveolus, H. francisci, H. lexi, H. luteus, H. luteofrenatus, H. margaritifer, H. microstomus, H. multidens, H. regani, H. roseopunctatus, H. scaphiceps, H. strigaticeps, H. tietensis, and H. variipictus by having conspicuous black dots on the body and fins (vs.pale or yellowish spots or blotches).The new species is further distinguished from the remaining Hypostomus species, except H. agna, H. brevicauda, H. brevis, H. garmani, H. heraldoi, H. hermanni, H. johnii, H. lima, H. luetkeni, H. nigropunctatus, and H. wuchereri, by the absence of ridges on the compound pterotic, predorsal plates and lateral series of plates (vs.having moderate to developed ridges on the compound pterotic, predorsal plates, and lateral series of plates).The new species differs further from H. agna, H. brevicauda, H. heraldoi, H. johnii, H. luetkeni, H. nigropunctatus, H. vermicularis, and H. wuchereri by the head and trunk being covered by large and conspicuous dark dots, the diameter of dots ranging from half to approximately one eye diameter (vs.small dots, similar in diameter to the pupil diameter or smaller); and from H. garmani, H. hermanni, H. lima, and H. mutucae by having the ventral surface of the body comparatively weakly covered by plates, that are restricted, when present, to the portion between the pectoral-fin bases (vs.ventral surface almost or completely covered by plates, including the median area between the pelvic fins).
Hypostomus jaguar is one of the two species of the genus that is endemic to the rio Paraguaçu basin.Its sympatric congener, H. chrysostiktos, has a higher number of branched dorsal-fin rays (10-11), which is a remarkable and unique characteristic within the Hypostomini, together with an inverted pattern of coloration.Thus, H. jaguar has external morphological features that are apparently more similar to congeners from other drainages (e.g., H. unae, known to the rio Una, rio Jequiriçá and rio das Almas basins) than with the sympatric H. chrysostiktos.Although a study of relationships was not performed, we suggest that the closest relatives of H. jaguar are possibly congeners from outside the rio Paraguaçu basin.The endemic nature of the rio Paraguaçu ichthyofauna has been previously highlighted (e.g., Lima & Gerhard, 2001;Santos & Zanata, 2006;Birindelli et al., 2007;Santos & Caramaschi, 2007) and a total of 16 described species are now known to be endemic to the basin.Hypostomus jaguar represents the tenth siluriform species that is apparently endemic to the Paraguaçu basin.Weber (2003) mentioned the possibility that H. wuchereri, a species with the vague type locality "Bahia", occurred in the rio Paraguaçu, as previously cited by Bitencourt et al. (2011).However, the examination of some of the type material of H. wuchereri revealed that it is a distinct species from H. chrysostiktos and H. jaguar, the two species that are known to occur in the rio Paraguaçu basin.Extensive collections in the rio Paraguaçu in the last 12 years failed to capture specimens of H. wuchereri and, consequently, the occurrence of the species in this river basin seems unlikely.A taxonomic study aiming to redescribe H. wuchereri and define its distribution is currently under way by the authors.
Fig.1.Dorsal profile of body convex from snout tip to dorsal-fin origin, straight and inclined from that point to middle of caudal peduncle, and straight or somewhat concave from end of adipose-fin spine to origin of dorsalmost caudal-fin rays.Ventral profile of body straight from snout to branchial aperture, straight to somewhat convex along abdomen, and straight and inclined from urogenital opening to caudal-fin base.Body relatively depressed; greatest body width at cleithral region, progressively tapering posteriorly from cleithrum; width at cleithral region greater than head depth.Greatest body depth at dorsal-fin origin, gradually tapering to caudal peduncle.Caudal peduncle robust, slightly flattened ventrally, in cross-section roughly trapezoidal on its anterior portion and more elliptical posteriorly.Head somewhat depressed, wide, and rounded anteriorly.Head without ridges.Posterior border of supraoccipital with small triangular process.Two plates fused to each other bordering posterior margin of supraoccipital.Interorbital region straight to somewhat convex, with lateral margins slightly elevated.Eye dorsolaterally positioned, relatively small.Dorsal iris operculum present.Mouth wide; roof and area anterior to dentary teeth covered by relatively small papillae.Lips rounded, of moderate size, occupying

Hypostomus jaguar, new species Figs. 1-2
Diagnosis.Hypostomus jaguar can be easily distinguished from the syntopic H. chrysostiktos by having seven unbranched dorsal-fin rays (vs.10-11), large dark dots on a clear background (vs.small yellow dots on a dark background), and 25 or 26 median plates(vs.27-29).It is distinguished from H. brevicauda and H. wuchereri by having head and trunk covered by conspicuous dark dots similar in size, ranging

Table 1 .
Morphometric data for Hypostomus jaguar.N = number of specimens; SD = standard deviation.Tips of first and last pterygiophores of dorsal fin lying above neural spines of vertebrae 7 and 16, respectively.Dorsal fin higher than length of its base; tips of adpressed last rays reaching anterior border of preadipose plate or, more rarely, the anterior border of adipose-fin spine.Posterior margin of dorsal fin slightly convex.Adipose-fin spine narrow, *, its border straight to slightly rounded and reaching fifth or sixth plate after its origin.Tips of first and last pterygiophores of anal fin lying below haemal spines of vertebrae 14 and 17, respectively.Caudal fin i,14,i(25)* or i,15,i(2), its posterior margin varying from somewhat concave to straight; lower unbranched ray somewhat longer than upper.All fin rays covered by odontodes, somewhat stronger on unbranched rays.Twenty nine vertebrae, three branchiostegal rays (1).