Five new species of genus Astyanax Baird & Girard , 1854 from Rio Iguaçu , Paraná , Brazil ( Ostariophysi , Characiformes , Characidae )

Five new species of the Neotropical characiform genus Astyanax Baird & Girard are described from Rio Iguaçu at the border of Paraná and Santa Catarina states, southeastern Brazil and Astyanax gymnogenis Eigenmann is redescribed. Each new species can be distinguished from all other Astyanax species from the upper Rio Paraná basin by exclusive combinations of: tooth shape, number of dental cuspids, distance between third infraorbital and preopercle, number of lateral line scales, longitudinal series of scales, number of gill-rakers and differences from shape of body and head traits. This study proposes the species of genus Astyanax from Rio Iguaçu as probably endemic, since all of them are absent from tributaries of the Rio Paraná hydrographic system. The high degree of diversification acquired by those Astyanax species in the Iguaçu basin may perhaps be allied to the long isolation period of this river from the Rio Paraná basin caused by the Iguaçu waterfalls. This barrier probably isolated those basins resulting in original groups of Characiformes and then Astyanax species, both isolated from one another and both different from their relatives in neighbouring basins.

In addition, the high endemism shown by the Astyanax species in Rio Iguaçu above Iguaçu waterfalls, has been recognised since Haseman (1911b), who observed the great diversity of Characiformes from Rio Paraná, when compared to the low number of fish families of this order from Iguaçu.The Iguaçu waterfalls produce a physical isolation between the rivers Iguaçu and Paraná.This fact was used by Haseman to explain the absence of a large number of migratory characiform fish species in Iguaçu; however, he did not discuss this matter regarding the Astyanax species diversification in this basin.
Fifty years later, Garavello (1977), when describing Apareiodon vittatus, examined the question of isolation of Rio Iguaçu ichthyofauna, mentioning several undescribed species for Astyanax in this basin.Godoy (1979), studying fishes from Segredo reservoir at medium Iguaçu, gave a short list of species including a reference to an unidentified Astyanax species.Menezes and Géry (1983) contributed with the description of Oligosarcus longirostris, observing the restriction of this species to above the Iguaçu waterfalls.In 1988, Sampaio (unpublished) revised the specific status of the characiform ichthyofauna of Rio Iguaçu, including diagnosis for some undescribed Astyanax species.After Sampaio, Severi and Cordeiro (1994) compiling Sampaio, catalogued the same Astyanax species as recognised by this last author.Garavello et al. (1997) provided diagnosis for six species of genus Astyanax and made mention to A. bimaculatus and A. gymnogenis from Rio Iguaçu.Following on, Almirón et al. (2002) describe Astyanax ita from lower Iguaçu next to Argentina.At the present time, Astyanax totae has been described from Iguaçu headwaters by Haluch and Abilhoa (2005); Abilhoa and Duboc (2007) also described Astyanax varzeae from headwaters of Rio Negro, and as a final point, Alcaraz et al. (2009) described Astyanax jordanensis from Rio Jordão, all three species described as allied to Astyanax scabripinnis (Jenyns, 1842).
In the present study we describe five new species for genus Astyanax from Rio Iguaçu and redescribe Astyanax gymnogenis Eigenmann, remarking the references given to: Astyanax scabripinnis and A. eigenmaniorum by Eigenmann (1921Eigenmann ( , 1927)); A. altiparanae by Graça and Pavanelli (2002), and other references to species of Astyanax by Ingenito et al. (2004).The present study also examines the high diversity of Astyanax species in the Rio Iguaçu and puts forward a discussion on the reasons that might have produced an amount of probably endemic Astyanax species at Iguaçu, and distinguishes them from their relatives from Rio Paraná.

Material and Methods
The specimens used in this study are housed in the following institutions: Museu de Zoologia, Universidade de São Paulo, São Paulo (MZUSP); Museu Nacional, Rio de Janeiro (MNRJ); Museu de História Natural Capão

Introduction
The genus Astyanax as defined by Baird and Girard (1854) based on Astyanax argentatus, was included as "Characini" fishes with an adipose fin present, characterised by an abdominal line not serrate, double rows of teeth on both jaws, flattened and with several conic spines or processes upon their edge; without canine or palatine teeth, dorsal fin above the pelvic fins and with large scales.The last complete revision of Astyanax was published by Eigenmann (1921Eigenmann ( -1927) ) and included seventy-four species and subspecies distributed from Rio Grande at the Mexico and United States border to south Brazil, Uruguay and Argentina.Eigenmann diagnosed the genus Astyanax as "compressed fishes, more or less elongate, rarely reaching a length of 150 mm SL, usually much smaller, but in one instance, A. maximus, reaching 200 mm in length; premaxillary with two series of teeth, the first series with several teeth; mandible with strong teeth in front, abruptly minute conical ones on the sides, without conical teeth in a second series; teeth of second series of premaxillary equal or graduated, usually five in number, four in a few species; crowns of premaxillary and mandibulary teeth usually ridged and denticulate; maxillary with a few or no (0-10) teeth; caudal naked; lateral line complete; gillrakers setiform; no predoral spine".After this revision by Eigenmann, only a comprehensive summary by Géry (1977) identified more than 60 species, including synonyms considering new subspecies, in a taxonomic proposal on the basis of Eigenmann's arrangement.Since Eigenmann's studies, Astyanax is considered one of the most specious genera of order Characiformes.Recently, Lima et al. (2003) considered the genus Astyanax as Incertae Sedis and with 85 species.
On the other hand, contributions to systematic of genus Astyanax in Rio Iguaçu comes from Eigenmann (1911b), who studied the Haseman's ichthyological collection and describe Astyanax gymnogenis, the genus Psalidodon, and new species for genera Hyphessobrycon and Glandulocauda.Measurements from specimens were taken with vernier calipers to nearest millimeter.The following sets of dimensions were taken: 1) Standard length: from tip of snout to base of caudal fin; 2) Head length: from tip of snout to posterior margin of opercle; 3) Snout length: from tip of snout to anterior margin of orbit; 4) Predorsal distance: from tip of snout to anterior base of first dorsal ray; 5) Preanal distance: from tip of snout to base of anal fin insertion; 6) Length of base of adipose fin; 7) Caudal peduncle depth: shorter distance from caudal peduncle; 8) Head depth: taken at occipital region; 9) Body depth: at dorsal fin origin; 10) Orbital diameter: taken horizontally; 11) Interorbital width: taken between eyes; 12) Mouth width: width of lower jaw.Those measurements were useful in meristic comparisons and they are expressed as proportions of body and head length inside diagnosis and in Tables 1, 2 and 3 Meristic characters were taken under the stereomicroscope, following basically Fink and Weitzman (1974)

Systematic Account
3.1.Provisional key for the six species of genus Astyanax herein described from Rio Iguaçu, above Iguaçu waterfalls 1. Teeth cusps in internal premaxillary series disposed in a straight line in ventral view; larger dentary teeth tricuspid; a dark brown vertically elongated humeral blotch; usually 6 gill-rakers on first epibranchial and 10-11 on hipobranchial arch (2) 1'.Teeth cusps in internal premaxillary series forming an arch, with a concave frontal surface in ventral view; larger dentary teeth with more than three cusps; humeral dark brown blotch almost circular or slightly horizontally elongated; usually 7-9 gill-rakers on first epibranchial and more than 13 on hipobranchial arch (3) 2. Margin of third infraorbital close to margin of preopercle, leaving a narrow naked area between these bones less than 1/5 of the depth of third infraorbital; teeth in external premaxillary series with only 3 cusps; maxillary bone short, forming a right angle with premaxillary when mouth is closed; a horizontally elongate dark brown caudal spot present Astyanax gymnogenis Eigenmann 2'.Margin of third infraorbital distant from margin of preopercle, leaving a wide naked area between these bones, varying from 1/5 to 1/3 depth of third infra-orbital; teeth in external premaxillary series usually pentacuspid; lateral cusps minute in non-symphysal teeth; maxillary bone long, forming an obtuse angle with premaxillary when mouth is closed Astyanax longirhinus n. sp. 3. Margin of third infraorbital close to margin of preopercle, leaving a nude area between these bones narrower than 1/5 of depth of third infraorbital bone; internal premaxillary series usually 5 or 6 penta or heptacuspid teeth; humeral blotch narrow, vertically elongate (4) 3'.Margin of third infraorbital bone isolated from preopercle margin by a large nude area, 1/5 or 1/3 of infraorbital depth; usually 4 pentacuspid teeth on internal premaxillary series; humeral blotch horizontally elongate or inconspicuous; lateral line usually 36 to 39 scales; humeral blotch oval or circular (5) 4. Cusps of non-symphysial teeth in premaxillary internal series in straight line or in slightly concave arch in ventral view; usually more than 2 maxillary teeth; external premaxillary series with 4 to 6 teeth, penta to heptacuspidate; premaxillary internal series with 5 teeth; first branchial arch usually 21 (9 + 13) to 29 (12 + 16) gill-rakers; a brown narrow and vertically elongate humeral blotch Astyanax minor n. sp.4'.Cusps of non-symphysial teeth in premaxillary internal series, forming a very concave arch in ventral  bone.Gill-rakers moderate in size; first branchial arch: 6 rakers in epibranchial and 10-11 in ceratobranchial + hypobranchial.
Premaxillary teeth in two series; external series with: 2-4 tricuspid teeth; internal with 5 teeth; teeth at symphysis bicuspid, others tricuspid.Maxillary with 1-3 teeth; teeth slightly compressed: 1 to 3 cusps.Dentary with 4 large anterior tricuspid teeth, followed ahead with a smaller tricuspid tooth and several minute teeth with 2 or 3 cusps.Dorsal-fin ii, 8-9.Its origin nearer tip of snout than caudal-fin origin; predorsal distance: 51.7 to 54.1 mm.Pectoral fin i, 12-13.Pectoral fin short, length: 19.6 to 20.1 mm, not reaching pelvic-fin origin, with 3 scales between tip of pectoral fin longest ray and pelvic-fin origin.Pelvic fin i, 7-8 rays, short, 15.0 to 15.3 mm in length, not reaching anal-fin origin; distance between tip of pelvic fin longest ray and anal-fin origin approximately half pectoral-fin length; pelvic-fin origin just anterior to dorsal-fin.Anal-fin: iii, 18-20 rays; origin posterior to vertical through posterior end of dorsal-fin base.No hooks in anal and pelvic-fin rays.
Lateral line 39-41 perforated scales.Scales above lateral line 7; scales below lateral line 5. Longitudinal scale series around caudal peduncle: 16; an axillary scale dorsal to pelvic-fin origin, near one fourth of pelvic-fin length; scale sheath at first third of anal-fin base.Occipital process: 3 scales in each side; predorsal series: 13 scales and preventral scales not forming in regular series.
Color in alcohol: Ground color range from creamy yellow to pale brown; ventral region pale brown with few chromatophores.Chromatophore concentration gradually increases from lateral line to dorsal region.Dorsal region dark, a vertical humeral light brown blotch and a horizontal lateral stripe slightly silvery, inconspicuous and pale at origin, increasingly darker posteriorly fused to caudal spot; caudal spot present at posterior end of caudal-peduncle and base of caudal-fin rays, extending to end of mid caudal-fin rays.Dorsal portion of eye above pupil darkish; pectoral and pelvic fins whitish; dorsal fin slightly darker due to chromatophore concentration; anal fin whitish except its margin; caudal-fin marginate and with higher chromatophore concentration.
Distribution: All specimens from Rio Timbó, medium and lower Rio Iguaçu.
Comments: The specimens from populations of A. gymnogenys here studied have some small differences when compared with holotype and cotype.The caudal spot current in fresh collected specimens is absent in holotype; the predorsal region is rounded forming a keel as in cotype but not in holotype; maxillary with 1 to 3 teeth and only 1 maxillary teeth in A. gymnogenys holotype.The distance between pectoral and anal-fin origins is greater than distance between anal-fin origins to base of caudal fin.In cotype of A. gymnogenys these measurements are equidistant.Also orbital diameter in fresh specimens is narrow than in the specimens of type series.Haseman, 22 Dec 1908 and FMNH 57359, 25, Porto União da Vitória, Rio Iguaçu, inundated margins, swamps and lagoon; Fowler, 1948: 59 (reference, Rio Iguaçu); Godoy, 1979: 11 (reference, Rio Iguaçu).
Diagnosis: Astyanax gymnogenis can be separated from all other Astyanax from Rio Iguaçu by the combination of the following characters: third infraorbital narrow, leaving a broad naked area between its border and preopercle corresponding to approximately one third depth of the bone; 5 premaxillary large teeth in the inner series all in a straight line in ventral view; symphysal pair bicuspid; maxillary short in relation to premaxillary, with 1 to 3 teeth, forming a right angle with premaxillary when mouth is closed; all other premaxillary (both series) teeth and larger (anterior) dentary teeth tricuspid; first branchial arch with 6 gill-rakers in epibranchial and 10 or 11 in lower branch (ceratobranchial + hypobranchial); presence of a vertically elongated humeral dark brown blotch and a horizontally elongated dark caudal brown spot.
Description: Morphometric and meristic data are available in Table 1.Standard length ranging between 138.8 to 146.5 mm.Body elongate and laterally compressed; greatest body depth: 35.7 to 39 mm, situated slightly anterior to dorsal-fin origin; predorsal profile concave from region just above eye to end of occipital process, convex from this point to dorsal fin origin.Dorsal fin base in a straight line; postdorsal profile slightly convex to adipose fin; ventral profile of head almost straight, strongly convex from pectoral origin to anal fin origin; anal fin base in a straight line.Head length: 22.9 to 25.1 mm.Snout pointed; snout length: 26.8 to 30.4 mm.Mouth small, terminal; upper jaw protrude slightly beyond lower jaw.Lower jaw delicate, length: 38.7 to 43.1 mm.Maxillary wide and long, maxillary length: 25.3 to 27.8 mm, reaching a vertical line through anterior border of pupil, forming a right angle with premaxillary when mouth is closed.Eye small, bony orbital diameter: 24.4 to 26.1 mm.Interorbital distance: 35.2 to 37.8 mm.Third infraorbital narrow, leaving a broad naked area between its posterior margin and preopercle, depth corresponding approximately one third of this Diagnosis: Astyanax longirhinus n. sp.can be distinguished from all other Astyanax from Rio Iguaçu by combination of following characters: third infraorbital narrow and deep, not in contact with preopercle, leaving an ample naked area between these bones.Teeth of premaxillary series straight; symphysal teeth of premaxillary internal series and dentary teeth tricuspid; teeth on premaxillary external series usually tricuspid, with lateral cusps minute when pentacuspid; remaining teeth in premaxillary internal series pentacuspid.Maxillary bone long, forming an obtuse angle with premaxillary bone when mouth is closed.Dentary large and provided with 4 large tricuspidate, followed by 3-5 tricuspid or pentacuspid teeth.
Description: Morphometric and meristic data are presented in Table 1.Standard Length ranging between 86.3-186.0mm.Body moderately high and elongate, laterally compressed; greatest body depth sited just anterior Eigenmann (1911) described Astyanax gymnogenys based on two specimens from Rio Iguaçu at União da Vitoria, central border of Paraná and Santa Catarina.It is possible that differences observed between type specimens and the fresh specimens studied are due to allometric growth rates, which could be considered as specific variation of A. gymnogenis.Also the poor conservation status of type material may perhaps correspond to upper described deformation.
Otherwise, the examination of paratype series of Astyanax scabripinnis paranae deposited in Field Museum (FMNH 54770) from ichthyological material collected by Haseman at Serrinha, Rio Iguaçu, Paraná, revealed that they comprise two species.From them, 39 specimens proved to be pertinent to Astyanax gymnogenis and they were separate from the lot FMNH 54770 of Astyanax scabripinnis paranae original series receiving numbers: FMNH 105094 (1 specimen) and 105095 (38 specimens).Also lots FMNH 57359 (25), FMNH 105096 (1) and 105097 (195) from Serrinha, and União da Vitória (Porto União), Paraná, revealed to be valid as Astyanax gymnogenis Eigenmann.So, those paratypes of Astyanax scabripinnis paranae are herein integrated as Astyanax gymnogenis, since specimens have tooth arcades and general features which permit the identification of this last species.
Type material examined: Brazil: Paraná: FMNH caudal peduncle to beyond mid caudal fin rays, following the silvery stripe.Pectoral and pelvic fins yellowish; anal fin slightly brown with chromatophores concentrated at margins and membranes of anterior rays; dorsal and caudal fin rays slightly darker than the remaining fin.
Color in life: Ground color slight brown at dorsum, a conspicuous dark brown vertical humeral blotch, and a large horizontal shine metallic silvery bar along lateral line.Abdomen yellow, sometimes orange at caudal fin, which is yellow or especially orange.Dorsal and pelvic fins yellowish; caudal and anal fins rays darker than others.
Etymology: The name longirhinus after Latin, longi = elongated and Greek, rhinos = nose.Meaning: long nose, in allusion to an elongated snout of this species, distinctive in Astyanax.
Distribution: This species is only known from medium and lower Iguaçu Basin.
Comments: With reference to Iguaçu species of Astyanax herein described, only Astyanax longirhinus and Astyanax gymnogenis has teeth on internal tooth series of premaxilla forming a straight line.It differs from remaining Iguaçu Astyanax species that have teeth of internal tooth series with small cusps forming an arch.to dorsal-fin origin, ranging between 34.4-59.4mm.Dorsal profile of head almost straight and elongate; predorsal profile slightly convex from occipital process to origin of dorsal-fin; dorsal fin base straight inclined; postdorsal profile slightly convex from dorsal fin insertion to base of caudal peduncle; caudal peduncle elevated; ventral profile slightly convex from anterior lower jaw to anal opening; anal fin base almost straight.
Premaxillary teeth disposed in two series.External series with 3-4 large tricuspid teeth; internal series with 5 symmetric teeth; teeth in premaxillary internal series and large teeth on dentary tricuspidate; non-symphysal teeth pentacuspid and with the most lateral cusps very minute and inconspicuous.Maxillary with 2-3 small tricuspid compressed teeth with inconspicuous lateral cusps.Dentary with a single series of 4 tricuspidate symphysal teeth, an extra lateral cusps minute when pentacuspid, followed by a variable number of 3-5 cuspidate teeth decreasing in size.
Dorsal-fin ii, 9 rays: 13.5-35 mm in the longest ray; dorsal-fin origin more distal from the tip of snout than the base of caudal fin rays.Pectoral-fin: 17.5-32.0mm long, not reaching the pelvic fin origin, and covering eigth scales of body when adpressed; i, 11 branched rays.Pelvic fin 1,7 rays: 16.0-27.0mm long, not reaching anal fin base; situated slightly after the vertical through dorsal fin origin and covering anal opening when adpressed.Anal fin ii (iii), 18-20 rays: 9.5-22.8mm; anal fin origin at vertical through tip of dorsal fin.No hooks in pelvic and anal fins.Lateral line 41-44 perforated scales; scales above lateral line 7 and under, usually 6.Longitudinal series of scales around caudal peduncle: 16; axillary scale dorsal to origin of pelvic-fin.Scale sheat in base of anterior anal-fin rays.Occipital process covered with 3 scales in each side.Scales of predorsal, postdorsal, preventral and preanal regions not formed in regular series.
Color in alcohol: Ground color creamy yellow; ventral region yellowish, with chromatophore concentration increasing gradually towards dorsal region; dorsal region slight brown with a large dark brown humeral bar vertically running by almost entire body depth; a conspicuous horizontal lateral silvery stripe as large as two series of scales running above lateral line, from posterior opercular region to end of caudal fin.A dark brown fine line running from ending Distribution: This species is known only from upper Iguaçu basin, found mostly in localities situated upstream of confluence with Rio Jordão.
Comments: Specimens of Astyanax minor were also compared with primary types of Tetragonopterus eigenmanniorum Cope, (ANSP 21598, 21599-21601 and 21267 and 21268).These two species showed differences on number of scales on lateral line: while minor has 36-39 perforated scales in lateral line, eigenmanniorum has only 32.With reference to the number of gill-rakers, A. minor is a form of Astyanax with 24-28 gill-rakers in first branchial arch, while A. eigenmanniorum only retains the regular count up for the genus: 15 to 20.Also the specimens identified by Eigenmann (1921: 310, FMNH 54740, 74 specimens from "Porto União, Rio Iguassu, Haseman, 29 Dec 1908") as A. eigenmanniorum was examined, and we conclude that those 74 specimens are, in fact, A. minor, and they are included in type series of this species herein described.So A. minor differ from A. eigenmanniorum and the presence of eigenmanniorum in the Iguaçu basin is here put in doubt, for despite strong collecting efforts, it has never been encountered in this basin.6) Astyanax fasciatus (non Cuvier, 1819: 352): Godoy, 1979: 11 (misidentification).

Astyanax bifasciatus new species (Figure
Astyanax sp B: Sampaio, 1988 (unpublished: 29, Figure 3); Severi andCordeiro, 1994: 21 (compilation from Sampaio, 1988) asymmetrical, with 7-9 cusps; cusps forming an arch with concave frontal surface in ventral view.Maxillary with 0-2, usually 1 heptacuspid tooth; most frequent combination 1/1, occasionally 1/0, and rarely 2/0, 2/1 or 2/2.Dentary with a single series of 4 large incisors with 7-9 cusps, followed by 2 abruptly smaller pentacuspid teeth and a variable number of minute usually tricuspid teet; teeth slightly asymmetrical due to a slight inclination to distal side and sometimes with an extra cusp on distal region.Dorsal-fin ii, 8-10 rays; closer to tip of snout than caudal-fin origin.Pectoral-fin i, 10-14 ray; pectoral-fin length: 18.6-23.8mm, not reaching pelvic-fin origin.Pelvic fin i, 7-8 rays.Pelvic-fin small: 14.4-19.7 mm, not reaching anal-fin origin; pelvic-fin origin slightly anterior to vertical line crossing through the dorsal-fin origin.In males, first through fifth branched rays with hooks on the ventral surface of posterior branch.Anal-fin: iii, 16-23 rays; anal-fin origin posterior to vertical line through the end base of dorsal-fin.Males with posterior unbranched ray and anterior branched rays with hooks.Hooks located on both sides of posterior surface of unbranched ray.Hooks on both sides of posterior main branch and only in posterior surface of branched rays; hooks larger and more numerous on surfaces of anterior branched rays, posterior rays without hooks.
Lateral line 36-39 perforated scales.Scales above lateral line with 6-7, usually 6; scales below lateral line usually 5-6.Longitudinal scale series around caudal peduncle: 15-17, usually 16 scales.An axillary scale located dorsally to pelvic-fin origin.Scale sheath present at anterior analfin-rays base.Occipital process with 3 sometimes, 4 scales on each side; scales at predorsal and preanal regions not formed in regular series.
Color in alcohol: Body ground color creamy yellow and ventral region light grey Chromatophore concentrations gradually increase from lateral line to dorsal region.A narrow, vertically elongated brown blotch on humeral region.An inconspicuous horizontal lateral stripe, faint at origin, increases dark to posterior end, where it fuses to a dark caudal spot.Caudal spot present at caudal peduncle and base of caudal-fin rays extending to mid caudal-fin rays to their ends; anal and caudal fin margins darker than rest of fin due to larger chromatophore concentration.
Color in life: Body silvery bright shined with the ventral region almost white; dorsal region slightly darker than the ventral region.A humeral bar vertically elongated a horizontal lateral stripe, and caudal spot much fainter than in preserved specimens.Fins hyaline; dorsal, adipose, caudal, anal, and pelvic fins slightly yellow; pectoral fins colourless.
Etymology: From Latin the name minor = small, in allusion to small body size of this species, when compared with remaining species of Astyanax from Iguaçu basin.
Sexual dimorphism: Anal-fin and pelvic-fin hooks present only in small specimens, only in males to 60.5 mm SL.Females larger than males; snout length and body depth proportionally larger in females; orbital diameter, length of anal, pectoral and pelvic fins larger in males.teeth in premaxillary internal series heptacuspid; vertical humeral bar with dorsal portion much wider than ventral portion; a faint and diffuse "post-humeral" spot; lateral line with 36-40 scales, usually 37 or 38; first branchial arch with 7-9, usually 8, rakers in upper branch and 10-13, usually 12, rakers in lower branch.
Description: Morphometrics and meristics data are presented in Table 2. Standard Length: 49.8-125 mm.Body moderately elongate, compressed laterally.Greatest body depth: 35.2-42.5 mm, slightly anterior to dorsal-fin origin.Predorsal profile convex from occipital process to dorsal-fin origin; base of dorsal-fin almost straight and postdorsal profile almost convex; ventral profile of head forming a continuous curve from lower jaw to pelvic-fin origin; usually straight from ventral fin to anal-fin origin; anal-fin base straight.
Premaxillary teeth in two series; external series with 3-6 pentacuspid teeth, usually 4; observed combinations: 4/4, 5/4 or 6/4, rare 4/3 or 3/3.Internal series usually with 5 pentacuspid teeth, rarely 4; teeth at symphysis asymmetric: proximal cusp small, second cusp largest, following cusps gradually smaller; other teeth symmetrical, in ventral view cusps form an arch with concave frontal surface.Maxillary with 0-2, usually 1 pentacuspid and compressed tooth; observed combinations: 1/1, 1/0 or 2/1.Dentary with a single series of 4 or 5 large pentacuspid incisors followed by 1 or 2 abruptly smaller pentacuspid teeth and a variable number of minute teeth with 1 or 2 cusps.Larger teeth symmetrical or slightly asymmetrical; tooth asymmetry due to an extra cusp on distal side or slight inclination to distal side or both.
Dorsal-fin with ii, 9-10 branched rays; dorsal-fin origin usually closer to tip of snout than to caudal-fin origin; pectoral-fin i,11-14 rays; pectoral-fin length: 20.7-25.7 mm, in smaller specimens pectoral fin reaches or approaches pelvic-fin origin; in larger specimens its tip ends 1 or 2 scales in front of pelvic-fin origin.Pelvic fin short: I, 7-8 rays: 15.3-19.9mm, reaching anus but not anal-fin origin; its origin slightly anterior to dorsal-fin origin.In males, first through fifth branched rays with slightly antrorse hooks on the ventral surface of posterior branch.Anal-fin: iii,19-24 rays; anal-fin origin posterior to vertical line drawn ventrally from end of dorsal-fin base.In males, posterior unbranched ray and anterior branched rays with hooks.Hooks on unbranched ray on both sides of posterior surface; hooks on branched rays on both sides of posterior main branch and posterior branch only; anterior branched rays with larger and more numerous hooks; posterior rays Diagnosis: Astyanax serratus n. sp.can be distinguished from all other Astyanax from Iguaçu basin by combination of the following characters: infraorbital 3 narrow and deep but not in contact with preopercle, leaving a naked area approximately 1/5 of height between border and preopercle; premaxillary external series with 2-5, usually 4 tricuspid teeth; non-symphysial teeth in premaxillary internal series pentacuspid; maxillary with 0-4, usually 2 teeth; humeral spot rounded and dark, frequently with a weak and narrow vertical downward prolongation.
Description: Morphometric and meristic data are presented in Table 3.Standard length ranging between: 6.5-124.1 mm.Body elongate, compressed laterally.Greatest body depth: 34.2-39.7 mm, situated slightly anterior to dorsal-fin origin; predorsal profile of head slightly concave to occipital process; convex from occipital process to dorsalfin origin; base of dorsal-fin almost straight.Postdorsal profile a straight line or slightly convex to caudal peduncle; ventral profile forming a continuous curve from lower jaw to anal-fin origin; anal-fin base almost straight.without hook.Anal-fin hooks slightly recurved; smaller and weaker than pelvic-fin hooks.
Lateral line 36-40 perforated scales, usually 37 or 38.Scales above lateral line 6-7; scales below lateral line usually 5, rarely 4 or 6; longitudinal series of scales around caudal peduncle 15 or 16.Axillary scale long, reaching from dorsal to pelvic-fin origin.Scale sheath present at anterior anal-fin-rays base.Occipital process with 3 scales on each side; scales in predorsal, preventral, and preanal regions not in regular series.
Color in alcohol: Ground color of body varying from creamy to whitish; ventral region pale brown with less chromatophore concentration, that gradually increases from lateral line to dorsal region; dorsal region dark with a vertical humeral bar present; its dorsal portion much wider than ventral portion; a faint and diffuse "post-humeral" spot, posterior to humeral bar, at origin of the horizontal lateral stripe.Horizontal stripe inconspicuous at origin, and increasingly darker to posterior end; it fuses to a dark caudal spot; pelvic and anal fins reddish.Caudal spot at caudal peduncle and base of caudal-fin rays, extending to mid caudal-fin rays to their ends.
Color in life: Body silvery, sometimes slightly golden; ventral region pale, almost white; dorsal portion of eye, above pupil, red; the humeral bar, the post-humeral spot and the horizontal lateral stripe, more conspicouos than in preserved specimens.Fins hyaline: dorsal and pectoral fins slightly yellow; caudal fin with a slight orange color; anal-fin and caudal-fin margins slightly darker than remaining fin due to higher chromatophore concentration.Aquarium specimens, when disturbed, fins may acquire stronger color: caudal may reach a reddish color, pelvic fin orange and anal vary from orange, at anterior half to yellow at posterior section.
Etymology: The name bifasciatus from Latin bis = double and fascia = stripe; transverse bars crossing other bars, in allusion to two vertical dark brown bars crossing humeral region.
Sexual dimorphism: Anal and pelvic fin hooks present only in males; smaller specimens (near 49.8 mm SL) also bearing hooks.Females grow larger than males; lower jaw proportionally larger in females; orbital diameter and pelvic-fin length proportionally larger in males.

Astyanax serratus new species (Figure
Holotype: MHNCI 12346, male 86.0 mm SL, Rio da Várzea, Agudos do Sul, Paraná, Brazil, J. C. Ribeiro, A. M. Prado and A. Dambros, 18 Nov 1983.Paratypes: Brazil, Paraná: MHNCI 12347, 7, 52.0-70.2mm SL, same data as holotype; MHNCI 12348, 3, 37.5-70.2mm SL, Curitiba, Rio Barigui (lago Barigui), concentration gradually increases from lateral line to dorsal region.A dark and circular humeral spot sometimes a weak and narrow vertical prolongation; a horizontal lateral stripe inconspicuous and faint at origin and increasingly darker to posterior end, where it fuses to dark caudal spot; lateral stripe with a silvery shine in some specimens Caudal spot extending to tips of mid caudal-fin rays.Pectoral and pelvic fins hyaline and with few chromatophores; dorsal, anal and caudal fins greyish, dark along the fin-membrane, between fin-rays; anterior and marginal regions of anal fin darker than remaining fin.
Color in life: Body silvery; humeral spot faint, sometimes inconspicuous; fins hyaline, sometimes with a slight yellowish tone.
Etymology: The name serratus from Latin: serra, serratilis = serrae is given in allusion to numerous fin hooks on pelvic-fin of males, resembling the profile of a serrae.
Sexual dimorphism: Anal and pelvic-fin hooks present only in males; only one male without pelvicfin hooks; smaller specimens (near 46.4 mm SL) with hooks; females usually larger in SL than males; lower jaw slight larger in females; maxillary bone, orbital diameter, pectoral-fin, pelvic-fin and anal-fin length proportionally larger in males.
Premaxillary teeth in two series, external series with 2-5 tricuspid teeth, usually 4; observed combinations: 4/4, few 4/3, rare 3/3, 4/2 or 5/4 teeth formulae.Internal series with 5 teeth; teeth at symphysis tetracuspid and asymmetric: proximal cusp small, second cusp largest, and following cusps gradually smaller; other teeth pentacuspid and symmetrical; in ventral view cusps forming an arch with concave frontal surface.Maxillary: 0-4, usually 2 tricuspid teeth; most frequent combination observed: 2/2, few 3/3 or 2/1; dentary with a single series of 4 large pentacuspid incisors sometimes with a small extra cuspid, followed by a variable number of abruptly smaller tricuspid teeth.Larger teeth gradually decreasing in size, but the insertion of second tooth is lower than insertion of third tooth, thus its largest cusp does not reach a line through the largest cusps of symphysal tooth and third tooth.Dorsal-fin ii, 8-9, usually 9 rays.Dorsal-fin origin normally closer to tip of snout than to caudal-fin origin; pectoral-fin i,11-13, usually 12 rays; pectoral-fin not reaching pelvic-fin origin; pectoral fin length: 16.9-21.7mm.Pelvicfin with i,6-8, usually 7 rays; pelvic fin small, its length: 14.5-18.7; in smaller specimens pelvic fins reaches analfin origin, in larger specimens it reaches the anal pore but not beyond that point; pelvic-fin origin slightly anterior to dorsal-fin origin.In males, branched rays of pelvic-fin with small, slightly antrorse hooks on ventral surface of ray; only one hook per ray-segment.Anal-fin iii,16-20, usually 16-17 branched rays; anal-fin origin posterior to vertical line through end of dorsal-fin base.In males, posterior unbranched ray and anterior branched rays with small and slightly recurved hooks; hooks on unbranched ray placed on both sides of posterior surface; hooks on both sides of main branch and on posterior branch; hooks larger and more numerous on anterior rays, posterior rays without hooks.Anal-fin hooks smaller and weaker than pelvic-fin hooks; only one hooks for each ray segment.
Lateral line 36-40 perforated scales.Scales above lateral line 6-7; scales below lateral line 5-6; longitudinal series of scales around caudal peduncle 16-20; an axillary scale dorsal to pelvic-fin origin; scale sheath at anterior anal-fin-rays base; origin of caudal fin scaled.Predorsal region usually with a regular series of 11-14 scales; scales in preventral region not forming regular series.
Color in alcohol: Ground color creamy yellow; ventral region pale, with few chromatophores; chromatophore branches; hooks larger and more numerous in anterior branched rays; posterior rays with few minute hooks or without hooks at all.
Lateral line 36-38 perforated scales.Scales above lateral line 5-7, usually 6; scales below lateral line 5-6.Longitudinal series of scales around caudal peduncle: 13-16.An axillary scale dorsal to pelvic-fin origin; scale sheath present at anterior base of anal-fin-rays.Occipital process with 3 scales on each side; predorsal region with usually regular series of 10-12 scales; scales in preventral region not forming regular series.
Color in alcohol: Ground color creamy yellow; ventral region pale, chromatophore concentration gradually increases to dorsal region, dorsal surface of head and mid-dorsal region dark; a faint, narrow and elongated vertical humeral brown bar present.A horizontal lateral brown stripe inconspicuous at origin and increasing dark pigment to posterior end is fused to caudal spot; caudal spot situated on caudal peduncle at base of caudal-fin rays; pectoral and pelvic fins nearly whitish and with few chromatophores; dorsal, anal and caudal-fin margins darker than remaining fins, due to higher chromatophore concentration; caudal-fin grayish.
Color in life: Body silvery; a dark humeral brown spot, a horizontal lateral stripe and an inconspicuous caudal spot; fins membrane hyaline or ranging to yellowish.
Etymology: The name dissimilis from the Latin dissimile = not similar, given in allusion to differences of this species in relation to the remaining species of Astyanax herein described.
Sexual dimorphism: Anal-fin and pelvic-fin hooks observed only on males; 75% of males without pelvic-fin hooks; standard length of smaller specimen with hooks: 38.2 mm.Females usually larger than males; snout, lower jaw, interorbital distance and body depth, comparative larger in females; head length, bony orbital diameter, pectoral-fin, pelvic-fin and anal-fin length proportionally larger in males.
Distribution: This species is known only from Iguaçu basin with wide distribution.

Discussion
The five new species of genus Astyanax herein described and A. gymnogenis, proved to be different from the species currently identified as: A. paranahybae, A. fasciatus, A. schubarti, A. eigenmanniorum, A. scabripinnis  Description: Morphometric and meristic data are presented in Table 3.Standard length ranging between 38.2-93.0mm.Body moderately elongate compressed laterally.Greatest body depth: 32.0-46.9mm, situated slightly anterior to dorsal fin origin.Dorsal profile varying from straight to slightly concave at head; predorsal profile convex from occipital process to dorsal-fin origin; dorsalfin insertion straight; postdorsal profile convex; ventral profile forming a continuous and somewhat pronounced curve from anterior lower jaw to anal-fin origin; anal-fin base straight.
Premaxillary teeth disposed in two series.External series: 2-5 tricuspid teeth, normally 4; most observed combinations 4/4 and few 4/3 dental formulae.Internal series: 4-5 teeth, usually 5; teeth at symphysis pentacuspid and asymmetric: proximal cusp small, second cusp is the largest, following cusps gradually smaller than second; other teeth in internal series pentacuspid and usually symmetrical but sometimes with one or two extra cusps; in ventral view cusps forming an arch with concave frontal surface.Maxillary: 0-3 teeth, usually one pentacuspid tooth; most observed combinations: 1/1, few 2/2 and 2/1.Dentary with a single series of 4 large pentacuspid, sometimes hexacuspid tooth followed by a variable number of abruptly smaller 3-5 cuspid teeth.Larger teeth gradually decreasing in size but the insertion of second tooth is far below the insertion of third; its largest cusp does not reaching a line through largest cusps of symphysal and third teeth.Dorsal-fin ii, 8-9 rays; dorsal-fin origin closer to tip of snout than to caudal fin base.Pectoral-fin: i, 11-13, normally 12 rays.Pectoral-fin not reaching pelvic-fin origin; pectoral-fin length: 18-25.6 mm.Pelvic-fin: i, 6-8, usually 7 rays; pelvic-fin length: 13.4-18.9mm, not reaching anal-fin origin.Pelvic-fin origin situated slightly anterior to dorsal-fin origin.In approximately 25% of the male specimens examined, branched rays with small conical or slightly antrorse hooks on the ventral surface of ray.Anal-fin: iii, 16-21, usually 18 or 19 rays; anal-fin origin posterior to vertical line through end of dorsal-fin base.In males, posterior unbranched ray and anterior branched rays with small conic or slightly recurved hooks; hooks on unbranched ray situated on both sides of posterior surface of ray; hooks on branched rays located only on both sides of posterior surface of main and posterior Rio Iguaçu and their relatives in southeastern Brazilian basins as assumed by Garavello (2005).
In view of the recognised allopatry on Tetragonopterinae species in these southeastern basins as considered by Weitzman et al. (1988), and in view of shared ancestors in old flood valleys of the continental shell on the Brazilian coast, we may suggest that the same might have taken place near Astyanax species from Rio Iguaçu.
At the present time, the Iguaçu Astyanax show similar species in isolated coastal rivers, especially in the Rio Ribeira de Iguape.In fact, the examination of type material of Astyanax ribeirae revealed it is similar to Astyanax minor herein described.A. ribeirae and A. minor have an elevated number of tooth cusps and a high number of anal-fin rays: 24-25 (A.minor) and 26-28 (A.ribeirae -holotype).So, we may assume that ancestral forms of Iguaçu Astyanax might be retained from other isolated earlier neighbouring basins in the past.
Other important information from recent palynological studies on Cenozoic deposits of sediment from Tremembé formation, Taubaté, São Paulo needs to be considered.Those sample stratums were redated, advancing to an Oligocenic age by Lima et al. (1985).The Characiform fishes found at this Oligocenic deposit are, according to Malabarba (1998), Megacheirodon unicus, Brycon avus, Lignobrycon ligniticus and Cyphocharax mosesi.The question is: those species represent modern lineages of characins?If so, the endemism of Rio Iguaçu Astyanax, as with the modern lineages Characiform fishes, were probably established in this basin earlier than the isolation arising from the formation of the Iguaçu waterfalls.
Consequently, it is plausible to suspect that Tetragonopterinae ichthyofauna that remain isolated at Rio Iguaçu arose from modern species derived in isolation and perhaps gave origin to the Astyanax lineage herein described.If this is correct, it is important to understand that this scenario of endemism for Astyanax species in Iguaçu is a general event, probably derived from other geographic episodes distinct from pure dispersion.
On the other hand, as indicated by Petri and Fulfaro (1983), the juvenile aspect of several geological regions of Rio Iguaçu, probably shows tectonic reactivation of several "breaks" along the basin.According to these authors, it may produce isolated amounts of water in some discontinuous regions, producing compartmentalisation.If these water supplies have existed for a long time, as Bigarella and Salamuni (1957) observe for the Curitiba basin, many environmental changes might have taken place throughout the Iguaçu basin in the past.Compartmentalisations perhaps brought about dramatic effects on ichthyofauna by introducing significant modifications on the habitat structure.In fact, fishes with reproductive migratory movements could be strongly affected, originating in the simplification of ichthyofauna, as recognised by Lowe McConnell (1975), an event that has always taken place when compartmentalisation occurs.
The evidence of compartmentalisation in Rio Iguaçu is corroborated by other recent descriptions of Astyanax series of scales on transversal line, while A. jordanensis have 35-38 scales on lateral line and 5-6/5 scale series on transversal line.All those last species was described as very similar to A. scabripinnis.They may be easily distinguished from the Iguaçu species here described by the combination of scale counts and tooth structure.The teeth structure in A. ita is characterised by the presence of penta to heptacuspidate teeth on each premaxillary and dentary, while A. totae, A. varzeae and A. jordanensis exhibit tri to pentacuspid teeth on premaxillary and dentary ramus.
The color pattern of Iguaçu Astyanax includes species with ground color ranging from whitish with belly silvery or hyaline, to creamy-yellow and reddish abdominal region.This reddish ground color pattern was registered mainly in the reproductive period when fishes receive strong melanin apport, well defining their differences in coloration.With the exception of A. serratus, no other studied species showed a color pattern including an almost circular or oval humeral dark blotch like A. altiparanae from the upper Rio Paraná basin.While A. longirhinus and A. gymnogenis showed patterns of creamy-yellow with an elongated vertical dark brown bar on the humeral region, A. bifasciatus joined orange reddish ground color of their bodies with an evident humeral vertically elongated dark blotch and a second vertical dark brown blotch, sometimes inconspicuous. A. minor and A. dissimilis on the contrary, show a bright silvery or hyaline coloration common to the majority of Astyanax species.
This study revealed A. gymnogenis and five new species as probably endemic from the Rio Iguaçu basin.Haseman (1911b) was the first author to discuss derivation of Iguaçu ichthyofauna.He assumed that the Iguaçu waterfalls were old and the current ichthyofauna of Paraná and La Plata river basins and thus, the ichthyofauna of Rio Iguaçu, were not apt to overtake the Iguaçu falls.
The possible endemism showed by Astyanax species from Iguaçu is here considered, in relation to their congeners from the upper Rio Paraná basin.Besides evidence coming from the recognised geographical events associated with the isolation occurring since the beginning of the Iguaçu falls, the exchange of ichthyofauna, mainly in headwaters, was assumed by Weitzman et al. (1988).They check the combination of stream capture events taken from upper land areas of Rio Iguaçu, and fluctuation of sea level affecting some lower coastal regions in the past.Furthermore, they posit these facts as the main factors to explain sympatry for Mimagoniates microlepis and M. lateralis in this area.
Several arrangements of near species from the same genus, sharing different isolated basins in southeastern Brazil, could be considered in this discussion.For example, Mimagoniates microlepis and M. lateralis; Corydoras barbatus and C. paleatus as cited by Weitzman et al. (1988); Oligosarcus longirostris from Iguaçu and Oligosarcus species from southeastern Brazil as discussed by Menezes (1988); Apareiodon vittatus from Iguaçu and A. piracicabae from upper Rio Paraná as studied by Garavello (1977), and the giant species Steindachneridion melanodermatum from of pelvic-fin rays; 10) Number of anal-fin rays; 11) Number of caudal fin rays; 12) Number of gill-rakers on first left-side branchial arch.Counts were herein utilised for differential diagnosis of all species.
. Type-material examined: Astyanax scabripinnis paranae Eigenmann, Tetragonopterus eigenmanniorum Cope, Astyanax ribeirae Eigenmann, Astyanax paranahybae Eigenmann, Astyanax gymnogenis Eigenmann; Astyanax hasemani Eigenmann; Astyanax bimaculatus novae Eigenmann; Astyanax bimaculatus paraguayensis Eigenmann; Astyanax schubarti Britski; . All teeth of both arcades were counted, but only those of the left side were considered.The number of unbranched fin rays is indicated by Roman characters, and branched rays by Arabic numerals.Gill-rakers were counted on first left branchial arch.The following counts were taken: 1) Number of teeth on premaxillary; 2) Number of teeth on dentary; 3) Number of teeth on maxillary; 4) Number of scales in lateral line; 5) Number of scales in transversal line; 6) Number of circumpeduncular scale series; 7) Number of dorsal-fin rays; 8) Number of pectoral-fin rays; 9) Number

Table 1 .
Morphometric and meristic data of Astyanax gymnogenis and Astyanax longirhynus stated as percents of SL and HL.

Table 2 .
Morphometric and meristic data of Astyanax minor and Astyanax bifasciatus expressed as percents of SL and HL.

Table 3 .
Morphometric and meristic data of Astyanax serratus and Astyanax dissimilis expressed as percents of SL and HL.

Astyanax serratus (n = 22) Astyanax dissimilis (n = 35) (mm) Holotype Range
paranae and A. altiparanae from the upper Rio Paraná basin.They are also different from Astyanax ribeirae from Xiririca, Rio Ribeira de Iguape and from A. ita, A. totae, A. varzeae and A. jordanensis from Rio Iguaçu.The combination of dental structure; number of scales of lateral, transversal, predorsal and preanal series; number of rays of pelvic and anal fins; number of gill-rakers and some body proportions, are responsible for exclusive diagnosis to those Iguaçu species of genus Astyanax.Astyanax longirhinus, A. bifasciatus, A. serratus, A. minor, A. dissimilis and A. gymnogenis has the internal premaxillary with 0-3, usually 1 tooth; faint, narrow and elongate vertical humeral bar present.