First record of the family Parodontidae ( Characiformes ) from the Paraíba do Sul river basin , southeastern Brazil

The first records of 2 species of Parodontidae (Apareiodon piracicabae and A. itapicuruensis) are reported in the Paraíba do Sul river basin. In total, 101 individuals of A. piracicabae and 3 individuals of A. itapicuruensis were collected in the Paraíba do Sul middle reaches. A description and diagnosis of both species based on morpho-meristic characters were provided. These fishes have been used as forage for larger fish species as well as bait for sport fishing, which may have facilitated their introduction in the Paraíba do Sul River from fish culture farms in the region.


Introduction
The Parodontidae family belongs to the Characiformes order and is comprised of 3 genera (Apareiodon Eigenmann, 1916, Parodon Valenciennes in Cuvier & Valenciennes, 1850, and Saccodon Kner, 1863) and 31 species (Eschmeyer and Fong 2017).This family is distributed throughout the South Americas and part of Panama, but absent in some South America coastal basins, in Patagonia, and in the Amazonian channel (Pavanelli 2003).Most of the species of this family, known as darter characins or scrapetooths, do not reach 150 mm in total length, do have fusiform bodies, and have the head without fontanel (Pavanelli 2003).
The genus Apareiodon has 18 valid species is defined by a spatulate and edentulous lower jaw (Pavanelli 2003, Pavanelli andBritski 2003).They are small individuals of low economic value and have already been used as forage for larger fish species and as bait for sport fishing (Bialetzki et al. 1998).Species of this genus shows trophic and habitat plasticity and are found dwelling in streams, rivers, and reservoirs (Bialetzki et al. 1998).This genus has been recorded in the Paraná, São Francisco, and Tocantins river basins and in small coastal rivers from northeast Brazil (Sazima 1980, Bialetzki et al. 1998, Pavanelli and Britski 2003).
In this study, we present the first records of Apareiodon itapicuruensis Eigenmann & Henn, 1916 and
Diagnostic characteristics for species identification were: (1) body height, (2) number of scales in the lateral line, (3) number of scales in the series between the isthmus and anus, (4) numbers of crossbars,and ( 5) number of dental cusps.These characters are commonly used in taxonomy and phylogeny of the genus Apareiodon by Pavanelli (2006).We also included an additional measure, following Pavanelli and Britski (2003): the distance between the isthmus origin and pectoral-fin origin.(Eigenmann & Henn, 1916) and Apareiodon piracicabae (Eigenmann, 1907) in the Paraíba do Sul river basin and their type localities.MC = main channel.N = number of examined specimens.Apareiodon itapicuruensis differed from other species of Apareiodon by the lower numbers of scales in the lateral line (35-36 vs 38-44), predorsal series (10-11 vs 12-14), numbers of scales in the series between the isthmus and the anus (23-24 vs 28-30), numbers of cuspids of premaxillary teeth (9-10 vs 12-16), and higher number of cuspids of maxillary teeth (7 vs 5-6).This species has body height between 25.0 and 26.1% SL (vs 20.3-24.4%  SL) (Table 2).Apareiodon piracicabae can be differed of other species by higher numbers of scales in the series between the isthmus and the anus (28-30 vs 23-24) and number of longitudinal strips (2 vs 1) (Table 3).Both species have mouth distinctly inferior, a dark streak along the lateral line, and a second one above the first or second row of scales above it.Apareiodon itapicuruensis has the head 4.5 times in the SL, depth 4-4.5 in the SL, dorsal 11-12 rays, anal 8 rays, eye diameter 1.25 in snout, 3.5 in the head, snout equal to interorbital, which is 3 times in the head, lateral line with 35-36 scales, and interorbital 3 times in the head length.Dorsal profile gently curved and ventral profile flattened, horizontal, or curved.Apareiodon piracicabae has the head 5 times in the SL, depth 4.33-4.75 in the SL, dorsal 10-12 rays, anal 8 rays, eye diameter 3.6-4 times in the head, lateral line with 41-43 scales, and interorbital less or equal to 1/3 of the head length.Dorsal and ventral profiles about equally arched.

Discussion
The occurrence of 2 species of the genus Apareiodon in the Paraíba do Sul river basin was recorded for the first time in this study, and their morphometrics, meristics, and patterns of color match with the diagnostic characters of the formal description for A. itapicuruensis and A. piracicabae.
Apareiodon itapicuruensisis only found in coastal basins of Bahia (Eigenmann 1916), approximately 1000 km far from the Paraíba do Sul river basin.It seems highly unlikely that the species occurs naturally in Rio de Janeiro and São Paulo states, with no recorded in Espírito Santo State that is located between those states.However, is important to bear in mind that still there are several streams and rivers still un-sampled or sub-sampled or even degraded habitats with punctual extinctions.Apareiodon piracicabae occurs in the São Francisco and in the Upper Paraná River basins, including the Jaguari and Atibaia river basins.These 2 rivers belong to the Cantareira System (Paraná River basin); a recent artificial connection, planned by the São Paulo government, with the Jaguari River (Paraiba do Sul river basin) will allow interchanges of fish fauna between the 2 basins.One of the hypotheses for the colonization of this species in the Paraíba do Sul river basin may be the leakage of fish culture farms, since there are records of species of the genus Apareiodon being used as forage for larger fish in the past (Bialetzki et al. 1998).On the other hand, it is known that the Upper Paraná, São Francisco, and Paraíba do Sul rivers share several fish species (Menezes et al. 2007), and this raises the possibility that A. piracicabae has naturally colonized the Paraiba do Sul river in the past, but further studies on this issue should be done to test this hypothesis.Similar to the characin Pseudocorynopoma heterandria Eigenmann, 1914, that is supposed to be introduced into the Paraíba do Sul river basin through fish culture farm leakage (Salgado et al. 2015), we should not disregard that both A. piracicabae and P. heterandria could have naturally colonized the Paraiba do Sul River, since both species have their original description form the Upper Paraná River basin.Another possible reason that reinforces the hypothesis of deliberate introduction in the basis is that these species have not been recorded before in the Paraíba do Sul River in spite of several previous studies in the basin.Further studies that incorporate examination of specimens of Apareiodon spp. in other areas and visit to museums should be done to make a more holistic determination of the geographical distribution of this genus.
Species invasions can cause the reduction in richness and diversity of native communities, or even species extinctions (Clavero and García-Berthou 2005, Pelicice and Agostinho 2009, Ortega et al. 2015).The invader Apareiodon spp., could, for example, compete with and harm the native genera of Astyanax [such as Astyanax hastatus Myers, 1928, Astyanax parahybae Eigenmann, 1908, Astyanax giton Eiganmann, 1908and Astyanax aff. bimaculatus (Linnaeus, 1728)], since they have similar size and morphological characters with probably similar functions in the environment.The discovery of possible invasive species can allow a better adaptation of conservation measures to be adopted targeting both invasive species (e.g.population control and better containment measures) and native species (e.g.assisted reproduction and restocking).

Figure 1 .
Figure 1.Map of the study area with new geographical distribution of Apareiodon itapicuruensis (triangle) and Apareiodon piracicabae (circles) in the Paraíba do Sul river basin.

Table 1 .
Information on geographic occurrences and type of gear (EF = electrofishing; GN = gill net) used to collect Apareiodon itapicuruensis records.Apareidon itapicuruensis: Brazil, Rio de