Rio Paraíba do Sul, rio Piabanha, and rio Doce basins, Brazil.

Hypomasticus mormyrops differs from H. thayeri by the moderate lips; mouth ventral; premaxillary and dentary teeth anteriorly oriented when mouth is closed; first teeth (close to the symphysis in the premaxilla and dentary) larger than the others.

Rio Paraíba do Sul and rio Jequitinhonha basins, Brazil.

Hypomasticus thayeri differs from H. mormyrops by the upper lip developed; mouth subterminal, not facing down; premaxillary teeth posteriorly oriented and dentary teeth anteriorly oriented when mouth is closed; three anterior teeth of premaxilla and dentary with similar size.

Figure 3. 

Characiformes species from the middle-southern Espinhaço mountain range, Minas Gerais state, Brazil A Hypomasticus thayeri, MNRJ 43577, 91.1 mm SL B Characidium fasciatum, MNRJ 48435, 68.8 mm SL C Characidium sp. A, MNRJ 46861, 65.5 mm SL D Characidium sp. B, MNRJ 48460, 56.2 mm SL E Characidium sp. C, MNRJ 46911, 42.3 mm SL F Astyanax lacustris, MNRJ 48521, 52.6 mm SL G Deuterodon giton, MNRJ 48129, 47.5 mm SL H Deuterodon intermedius, MNRJ 47840, 42.1 mm SL I Deuterodon pedri, MNRJ 48381, 65.5 mm SL J Deuterodon aff. taeniatus, MNRJ 45824, 55.5 mm SL K Hasemania nana, MNRJ 48440, 28.4 mm SL L Hasemania sp., MNRJ 48416, 25.1 mm SL M Oligosarcus argenteus, MNRJ 48393, 82.6 mm SL N Piabina argentea, MZUSP 110200, 44.2 mm SL O Psalidodon rivularis, MNRJ 48516, 46.8 mm SL P Psalidodon sp. MNRJ 48128, 59.4 mm SL Q Hoplias intermedius MZUSP 54696, 40.4 mm SL.

Rio Amazonas, rio Paraná-Paraguay, and rio São Francisco basins: Brazil, Ecuador, Colombia, Bolivia, Paraguay, and Peru.

Leporellus vittatus is diagnosed by having two longitudinal dark stripes on upper and lower lobes and one on the caudal fin median rays.

Rio Paraná and upper rio São Francisco basins, Brazil.

Leporinus amblyrhynchus differs from its congeners by a longitudinal dark band on the sides of the body and 8–10 transversal dark bands on the dorsal region.

Rio Paraíba do Sul and rio Doce basins, Brazil.

Leporinus copelandii differs from its congeners by having three rounded or slightly rectangular spots conspicuously distributed in median line of the body, respectively below dorsal fin, below adipose fin and at the end of caudal peduncle; and all fins presenting reddish color.

Rio São Francisco basin, Brazil.

Leporinus marcgravii differs from its congeners by having several conspicuous maculae throughout the lateral line and smaller maculae above and below lateral line; hyaline or slightly darkened fins base.

Rio das Velhas, rio São Francisco basin, Brazil.

Leporinus taeniatus differs from its congeners by dark macula in the maxilla and reddish pigmentation under the longitudinal dark band.

Upper rio Paraná, rio Jacuí, rio São Francisco, rio Paraguay, and rio Uruguay basins.

Rio São Francisco basin.

Characidium fasciatum differs from Characidium sp. A by the high or little tapered snout; adult specimens with vertical bars without defined shape or almost missing in the lateral of the body; narrow longitudinal dark band occupying less than one scale; pigmentation on caudal fin rays not forming conspicuous bands or just forming narrow bands. Distinguished from Characidium sp. B by having 36 or 37 perforated scales in the lateral line; four series of scales below lateral line.

Upper rio Santo Antônio, rio Doce basin.

Characidium sp. A differs from its congeners of this study by having very tapered snout; wide and conspicuous vertical bars in the lateral of body in both juveniles and adults specimens; longitudinal dark band occupying one or more scales; one-two dark, wide and conspicuous bands in half of caudal fin rays and another in the base of first and posterior caudal fin ray.

In this study, we refer Characidium sp. A such as a first putative new species from the rio Doce basin, due to differences in morphology and color pattern between this species and another similar ones from Southeastern Brazil river basins such as C. alipioi, C. grajahuense, C. lagosantense, C. lauroi, and C. timbuiense.

Upper rio Santo Antônio, rio Doce basin.

Characidium sp. B differs from its congeners from the study area by predorsal length less than 45% of total length; lateral vertical bars absent or without defined shape; dark maculae on caudal fin not forming defined bands.

In this study, we refer Characidium sp. B such as a second putative new species from the rio Doce basin, due to differences in morphology and color pattern between this species and another from Southeastern Brazil river basins such as C. alipioi, C. grajahuense, C. lagosantense, and C. lauroi.

Upper rio Santo Antônio, rio Doce basin.

Characidium sp. C differs from its congeners from the study area by predorsal length up to 55% of total length; vertical bars always arranged above and below the lateral line in a “y” or “yy” shape; weak of narrow dark band on caudal fin.

In this study, we refer Characidium sp. C such as a third putative new species from the rio Doce basin, due to differences in morphology and color pattern between this species and another from Southeastern Brazil river basins such as C. cricarense and C. litorale.

Rio Paraíba do Sul and rio Doce basins.

Brycon opalinus is diagnosed from its congeners by having one humeral spot and another in the caudal peduncle, never extending up to median caudal fin rays; tubules of the lateral line without secondary branches.

Rio São Francisco basin, Southeastern Brazil.

Astyanax lacustris differs from Astyanax sp. by the absence of teeth in maxillary bone; a conspicuous oval humeral spot arranged horizontally; hyaline fins usually yellowish, more evident in the caudal fin. It is also diagnosed by having 33–36 perforated scales in lateral line; 26–29 branched rays in anal fin; 6.5–7.5 scales above and 5.5–6.5 scales below lateral line.

Upper rio Santo Antônio, rio Doce basin.

Astyanax sp. differs from A. lacustris by having teeth in maxillary bone; conspicuous humeral spot vertically oriented; hyaline fins slightly reddish. It is also diagnosed by having teeth tetracuspidate to heptacuspidate in the inner series of premaxillary bone forming a notch; dentary teeth decreasing abruptly in size from fourth tooth; 6.5 scales above the lateral line; iii+19 or 20 anal fin rays.

In this study, we refer Astyanax sp. such as putative new species from the study area, due to differences in morphology and color pattern between this species and another from Southeastern Brazil river basins such as A. microschemos and A. turmalinensis.

Rio Paraíba do Sul, Brazil.

Deuterodon giton differs from its congeners of the study area by having dentary teeth decreasing gradually in size until the sixth or seventh tooth; dentary with more than five cusps (usually seven or eight); infraorbital 3 totally exposed, with almost no naked area prior to preopercle; infraorbital 3 shiny due to high concentration of guanine crystals and low concentration of chromatophores.

Deuterodon giton is described from the rio Paraíba do Sul basin. However, in the present study it was found in the rio Doce basin, confirming the first record of the species for this basin. The difference observed in the specimens between both morphotypes is a tendency of longer length in adult specimens from the rio Paraíba do Sul basin.

Rio Paraíba do Sul basin and coastal drainages in state of Rio de Janeiro, Brazil.

Deuterodon intermedius can be distinguished from its congeners of the study area by the absence of space in the symphysis of dentary; five tetracuspidate to hexacuspidate teeth in the inner series of the premaxillae; infraorbital 3 without chromatophores; small humeral spot, sometimes slightly rounded in smaller specimens; no more than 1.5 scales below the lateral line; 35–37 perforated scales in the lateral line

Deuterodon intermedius is described from the rio Paraíba do Sul basin. However, in the present study it was found in the rio Doce basin. The only difference observed in the specimens between both morphotypes is a tendency of longer length in adult specimens from the rio Paraíba do Sul basin.

Rio Doce basin.

Upper rio Santo Antônio, rio Doce basin.

Deuterodon aff. taeniatus differs from its congeners of the study area by the presence of a space in the symphysis of dentary; infraorbital 3 with high concentration of chromatophores; usually verticalized humeral spot with a lower comma-shaped feature, reaching 2.5 scales below the lateral line; 32–39 perforated scales in the lateral line; iii-v+17–24 anal fin rays.

Deuterodon taeniatus is described from the rio São João and rio Macaé basins (rio Paraíba do Sul basin), in state of Rio de Janeiro, Brazil. The presence of the species in different basins has been notified in literature (Vieira 2006; Alves and Pompeu 2010) and sometimes with imprecise taxonomy (e.g., Alves et al. 2008; Vieira et al. 2015). In this study, A. taeniatus was recorded only for the rio Doce basin. However, it was observed that specimens from the rio Doce basin have lower body depth when compared to the morphotypes from rio Paraíba do Sul basin.

Upper rio Santo Antônio, rio Doce basin.

Deuterodon sp. differs from its congeners from the study area by having five hexacuspidate to heptacuspidate teeth in the inner series of the premaxillae; cusps straight, not forming notch; infraorbital 3 with naked area anteriorly, and below it; low concentration of chromatophores in the infraorbital 3; inconspicuous humeral spot slightly verticalized, straight anteriorly and straight or half-moon shaped posteriorly; 5.5 scales above lateral line; iii+21 anal fin rays.

In this study, we refer Deuterodon sp. such as putative new species from the rio Doce basin, due to differences in morphology and color pattern between this species and another from southeastern Brazil river basins such as D. giton, D. intermedius, and D. taeniatus.

Rio São Francisco basin.

Hasemania nana differs from Hasemania sp. by having 13–19 branched rays in anal fin and absence of rounded blotch in the median caudal fin rays.

Hasemania nana is an endemic species from the rio São Francisco basin. However, in the present study it was found in the rio Doce basin, confirming the first record of the species for this basin. The only difference observed in the specimens between both morphotypes is a tendency of higher number of anal fin rays in the specimens from the rio Doce basin (13–19 vs. 13–16). The higher number of anal fin rays is congruent to the H. nana morphotype from the rio Paraopeba (rio São Francisco basin).

Upper rio Paraúna, rio São Francisco basin.

Hasemania sp. differs from H. nana by having 11–14 branched rays in anal fin and presence of rounded blotch in the base of median caudal fin rays.

In this study, we refer Hasemania sp. such as putative new species and second record from the rio São Francisco basin, due to differences in morphology and color pattern between this species and another from Southeastern Brazil river basins such as H. bilineata, H. crenuchoides, H. nana, and H. uberaba. In the taxonomic revision carried out by Serra (2003) there is no mention of the morphotype. The same have occurred in Vieira et al. (2015) resulting here in the first record of the taxon for the basin.

Rio Doce, rio Paraíba do Sul, upper rio Paraná, rio Paraguay, and rio Jequitinhonha basins, in Brazil, and some drainages in Bolivia and Paraguay.

Occurrence of K. moenkhausii in the rio Doce basin was already confirmed. Different studies have mentioned about such record (dos Santos 2015; Vieira et al. 2015; Sales et al. 2018). In Vieira et al. (2015) the species was identified such as K. cf. moenkhausii. In tributaries of the rio Santo Antônio basin is quite common to collect it. However, it may be an exotic species which was introduced on the basin in the past (Vieira et al. 2015), but future research will be needed to confirm how the species reached the basin. Souza et al. (2015) revealed through DNA barcoding technique that K. moenkhausii has been shared throughout rio São Francisco, rio Paraíba do Sul and upper rio Paraná basins, through recent interchange. According to the authors, the species represent a single panmitic species, and its sharing in those basins may have occurred due to different human activity processes, such as intentional introduction, transposition of natural barriers or accidental escape in ornamental fish trade.

Rio Doce, rio das Velhas, and upper rio Paraná basins, Brazil.

Oligosarcus argenteus is diagnosed by having 17–24 teeth in maxillary bone; 44–48 perforated scales in lateral line; 8–9 series of scales above and 6–8 below lateral line; iv-v+20–25 branched rays in the anal fin; 17–20 scales around caudal peduncle.

Rio São Francisco basin, Brazil.

Upper rio Paraná, rio São Francisco, rio Itapicuru, rio Paraíba do Sul, and rio Itapemirim basins: Brazil and Paraguay.

Piabina argentea is diagnosed by having longitudinal dark band in the lateral of the body; dark spot in caudal peduncle absent; 18–21 rays in anal fin.

Rio São Francisco basin, Southeastern Brazil.

Psalidodon rivularis differs from its congeners of the study area by having premaxilla aligned with dentary in lateral view; four or five wide teeth in the inner series of premaxilla (if present, the fifth tooth is too small or not aligned with others); chromatophores surrounding abdominal scales and in higher concentration on the base of scales; developed scales in pectoral, pelvic, and anal fins.

Psalidodon rivularis was originally described as an endemic species from the rio São Francisco basin. However, in the present study it was found in the rio Doce basin, confirming record of the species in this basin. Oliveira (2017) also confirmed the occurrence of P. rivularis as such as from the headwaters of rio Doce plus the headwaters of rio Jequitinhonha basin, while suggesting the synonymy of Astyanax turmalinensis (Triques, 2003) with Psalidodon rivularis.

Upper rio Paraúna, rio São Francisco basin, and upper rio Santo Antônio, rio Doce basin.

Psalidodon sp. can be distinguished from its congeners from the study area, except of P. rivularis, by higher body anteriorly to dorsal fin origin; from A. rivularis by having premaxilla slightly in front of dentary in lateral view; five narrow teeth aligned in the inner series of premaxillary bone; two narrow vertical lines of chromatophores surrounding border of abdominal scales; small hooks in pectoral and anal fins in mature males.

In this study, we refer Psalidodon sp. such as putative new species from the study area, due to differences in morphology and color pattern between this species and another Stethaprioninae from Southeastern Brazil river basins, such as P. fasciatus, P. rivularis, A. scabripinnis, and A. turmalinensis.

Rio São Francisco and rio Paraná basins plus tributaries of the rio Doce, Brazil.

Hoplias intermedius is diagnosed by having 4–6 pores in lateral sensory system of the ventral surface of dentary; 42–46 perforated scales in lateral line; dark or light brown color in head and body.

Middle rio São Francisco basin, Minas Gerais, Brazil.

Bunocephalus hartii is diagnosed by the absence of hooks throughout anterior margin of spine of pectoral fin; posterior ray of dorsal fin completely or almost adnate to dorsum.

Figure 4. 

Siluriformes species from the middle-southern Espinhaço mountain range, Minas Gerais state, Brazil A Bunocephalus hartti, MZUSP 064227, 44.7 B Trichomycterus melanopygius, MNRJ 47902, 85.2 mm SL C Trichomycterus sp. A, MNRJ 47901, 87.4 mm SL D Trichomycterus sp. B, MNRJ 46932, 57.0 mm SL E Callichthys callichthys, MNRJ 48501, 58.2 mm SL F Euryochus thysanos, MNRJ 47897, 74.4 mm SL G Harttia intermontana, MNRJ 48463, 42.4 mm SL H Hypostomus francisci, MZUSP 37162, 66.8 mm SL I Neoplecostomus sp. A, MNRJ 46935, 73.0 mm SL J Neoplecostomus sp. B, MNRJ 48431, 43.0 mm SL K Pareiorhaphis scutula, MNRJ 48471, 88.1 mm SL L Pareiorhaphis vetula, MNRJ 46936, 40.4 mm SL.

Rio Doce basin, in the states of Minas Gerais and Espírito Santo, Brazil.

Trichomycterus alternatus differs from its congeners of the rio Doce and rio São Francisco basins by having seven branchiostegal rays; yellowish to light brown body color; rectangular or rounded sequential dark maculae at the midline of the body, sometimes fused and with a vermicular pattern, or forming a narrow stripe from the post-opercular region to the base of caudal fin; a row of rectangular sequential middorsal maculae, round or fused to maculae of the midlateral of the body; subtruncate caudal fin.

Tributaries from rio Doce basin.

Trichomycterus melanopygius differs from its congeners of the study area by the absence of evident maculae, spots, streaks and/or stripes on the flanks and dorsum of the body; i+7 (rarely i+8) pectoral fin rays; dark band in the median caudal fin rays.

Upper rio Santo Antônio, rio Doce basin.

Trichomycterus sp. A is distinguished from its congeners of the study area by the spotted body due to high concentration of large maculae with no defined shape; caudal fin strongly truncated; eight branchiostegal rays; few dorsal procurrent rays (14 or 15).

In this study, we refer Trichomycterus sp. A such as a putative new species from the rio Doce basin, due to differences in morphology and color pattern between this species and another with similar color pattern from Southeastern Brazil river basins such as T. auroguttatus, T. albinotatus, T. brasiliensis group, T. caipora, T. argos, T. novalimensis, and T. rubiginosus.

Upper rio Paraúna, rio São Francisco basin, and upper rio Santo Antônio, rio Doce basin.

Trichomycterus sp. B differs from its congeners of the study area by having nine branchiostegal rays; high concentration of rounded dark spots on the head and sides of the trunk, dorsum, and belly, which may fuse and form small vermiculations; rounded caudal fin.

In this study, we refer Trichomycterus sp. B such as a putative new species from the rio Doce basin, due to differences in morphology and color pattern between this species and another with similar color pattern from Southeastern Brazil river basins such as T. brasiliensis group, T. argos, T. landinga, T. novalimensis, and T. rubiginosus.

Drainages from Colombia to the Río de La Plata basin, South America.

Widespread in South America.

Coastal rivers in Eastern Brazil, from the rio Itapemirim, and including the larger basins of the rio Doce and Mucuri, in Espirito Santo and Minas Gerais states, to the rio Frades, state of Bahia.

Euryochus thysanos is diagnosed by having rounded and short inferior lip, leaving a large naked area in the ventral portion of head; inferior lip with barbel developed; 30–35 bicuspidate teeth in the premaxillary and dentary bones; absence of hypertrophied odontodes.

Upper rio Santo Antônio, rio Doce basin.

Harttia sp. differs from H. intermontana by inferior region of orbit straight; compressed and narrow plates with developed odontodes in the dorsal and ventral region of caudal peduncle.

In this study, we refer Harttia sp. such as a putative new species from the rio Doce basin, due to differences in morphology between this species and another from Southeastern Brazil river basins such as H. carvalhoi, H. garavelloi, H. leiopleura, H. loricariformis, H. novalimensis, and H. torrenticola.

Upper rio Doce basin, Brazil.

Harttia intermontana differs from Harttia sp. by having orbit rounded; short and wide plates with poorly developed odontodes in the dorsal and ventral region of caudal peduncle.

Upper rio Santo Antônio, rio Doce basin.

Hypostomus sp. differs from H. francisci by having black and large spots in the head and throughout the body.

The only juvenile specimen collected in the study area was analyzed in such a way that is not possible to mention about species level identity or if it configures into a new species.

Rio São Francisco and rio Paraná basins.

Hypostomus francisci can be distinguished from Hypostomus sp. by pale small, rounded spots in the whole body, including in the fins; spine of the dorsal fin slightly smaller than predorsal distance.

Upper rio Santo Antônio, rio Doce basin.

Neoplecostomus sp. A differs from Neoplecostomus sp. B by the maxillary barbels poorly developed; premaxillary teeth and dentary with separate cusps and large concavity between them; lateral and central cusps with similar size; no developed papillae between branches of dentary; plates between dorsal and adipose fin meeting on the back of the dorsum.

In this study, we refer Neoplecostomus sp. A such as a putative new species from the rio Doce basin, due to differences in morphology between this species and another from the rio Doce basin such as N. doceensis, and N. pirangaensis.

Upper rio Paraúna, rio São Francisco basin.

Neoplecostomus sp. B differs from Neoplecostomus sp. A by the maxillary barbels developed; premaxillary teeth and dentary with close cusps; median cusp more developed than lateral one; plates between dorsal and adipose fin not meeting.

In this study, we refer Neoplecostomus sp. B such as a putative new species from the rio São Francisco basin, due to differences in morphology between this species and another from rio São Francisco basin such as N. franciscoensis.

Upper rio Doce basin, Brazil.

Pareiorhaphis scutula differs from its congeners of the study area by having abdomen with small plates covered by skin from the pectoral fin region to insertion of pelvic fins; fins with pale yellow and light brown spots.

Rio Doce basin, Brazil.

Pareiorhaphis vetula can be distinguished from its congeners of the rio Doce basin by inferior lip with maxillary barbels completely adnate; elongated and pointed urogenital papilla.

Upper rio Paraúna, rio São Francisco basin.

Pareiorhaphis sp. differs from Pareiorhaphis scutula by the abdomen without plates; from P. scutula and P. vetula by the pectoral, pelvic and anal fins with clear color; dark caudal with clear borders. Pareiorhaphis sp. can still be distinguished from Pareiorhaphis vetula by inferior lip with developed maxillary barbels; urogenital papilla with normal size, not elongated.

In this study, we refer Pareiorhaphis sp. such as a putative new species from the rio Doce basin, due to differences in morphology between this species and another from rio Doce basin such as P. nasuta, and P. proskynita.

Upper rio Paraná and rio São Francisco basins, Argentina and Brazil.

Coastal river drainages from state of Rio de Janeiro to state of Santa Catarina, Brazil (Angrizani & Malabarba, 2020).

A redescription of R. quelen was made, and the original locality where it comes from is rio Macacu drainage, a tributary of rio Soarinho, in the municipality of Cachoeira de Macacu, state of Rio de Janeiro, Brazil.

Rio das Velhas drainages in rio São Francisco basin, Brazil.

Rio São Francisco basin, Brazil.

Upper rio Paraúna, rio São Francisco basin, and upper rio Santo Antônio, rio Doce basin.

Gymnotus carapo group is diagnosed by having the mouth upturned, pronate; rictus curved ventrally; eyes positioned below half of median line of the head; branchial opening throughout the posterior margin of opercle; oblique and conspicuous dark bands in the lateral of the body, from dorsal region to ventral surface of preanal; longitudinal band reaching the base of the anal fin.

Although G. carapo is widespread from Trinidad and Tobago to Argentina, in this study we refer the species as G. carapo group, since the taxonomic status of G. carapo is uncertain for the Southeastern and Southern Brazil and may represent more than one species. A taxonomic review of the G. carapo group in Central and South America is needed.

Figure 5. 

Fish species from the middle-southern Espinhaço mountain range, Minas Gerais state, Brazil A Gymnotiformes (Gymnotus carapo group, MNRJ 48407, 130.5 mm SL) B Synbranchiformes (Synbranchus marmoratus group, MNRJ 48448, 116.8 mm SL) C Cyprinodontiformes (Phalloceros uai, MNRJ 48408, 32.0 mm (female – above) and 16.3 mm (male – below) SL) D Cichliformes (Australoheros mattosi, MNRJ 48454, 54.6 mm SL E Cichliformes (Australoheros sp., MNRJ 46859, 39.3 mm SL).

Widespread from rio Orinoco to rio de La Plata basin.

Eigenmannia virescens is diagnosed by having small branchial opening, smaller than the snout; body light brown, maculae absent.

Upper rio Santo Antônio, rio Doce basin.

Synbranchus marmoratus group is diagnosed by having dark-brown color on dorsal region of body and light brown below the midline and head; many rounded dark spots or irregularly shaped dark spots throughout the whole body; dark stripe composed by fusion of many dark spots in ventrolateral region of head.

Albeit the true S. marmoratus have a wide distribution in the Neotropical region, in this study we refer the species as S. marmoratus group, since the taxonomic status of S. marmoratus may represent more than one species. A taxonomic review of S. marmoratus from Central and South America is needed to clarify this problematic issue.

Rio Paraná-Paraguay basin and coastal rivers from rio Itabapoana to rio Araranguá, in Brazil, Paraguay, and Argentina.

Phalloceros harpagos differs from P. uai by having gonopodium with hook in the two gonopodial appendages in males positioned close to the appendages; distal half of the appendage narrower than proximal half; urogenital papilla centralized in females, positioned between anus and the base of first anal fin ray.

Albeit P. harpagos presents a relatively wide distribution in coastal drainages of Brazil, here we present the first record of the species in the rio Santo Antônio basin.

Rio das Velhas, rio São Francisco basin, Brazil.

Phalloceros uai differs from P. harpagos by having gonopodium with small left hook facing down or up and forward in males, situated near to gonopodial appendage base; right hook absent; urogenital papilla directed to the right side in females, positioned laterally; anal opening in contact with first anal fin ray or close to it.

Phalloceros uai is an endemic species from rio São Francisco basin and, in this study, we present the first record for the rio Santo Antônio basin. Vieira et al. (2015) recorded the species in the rio Piracicaba, another important drainage from the rio Doce basin. The distribution of the species in adjacent basin deserves further research, and it is still being carefully investigated.

Trinidad and Tobago in Central America and Northern South America.

Poecilia reticulata was widely introduced in aquatic environments in Brazil, so its occurrence in many rivers of the country is quite common nowadays.

Rio São Francisco basin, Southeastern Brazil.

Australoheros mattosi differs from Australoheros sp. by having XVI–XVII+9–11 dorsal fin rays; VII–VIII+9 anal fin rays.

Upper rio Santo Antônio, rio Doce basin.

Australoheros sp. differs from A. mattosi by having XVIII+7 dorsal fin rays; VIII+7 anal fin rays.

In this study, we refer Australoheros sp. such as putative new species due to differences in morphology between it and another from rio Doce basin, since A. perdi and A. ipatinguensis seems to be restricted to small areas such as lagoons and small rivers in the rio Doce basin. However, a higher number of specimens with difference sizes is needed and a taxonomic review of the cichlid Australoheros genus as well.

coastal drainages in eastern Brazil.

An identification key for its species from the study area is provided.