Redescription of Moenkhausia doceana ( Steindachner , 1877 ) ( Ostariophysi : Characiformes ) : a characid from the Northeastern Mata Atlântica ecoregion , Brazil

Moenkhausia doceana is redescribed from the Northeastern Mata Atlântica ecoregion drainages in Espírito Santo, Minas Gerais, and Bahia states. The species is distinguished from its congeners by a long anal fin, with 29-34 (mode 32) branched rays; 4-7 (mode 5) maxillary teeth; and 7-8 (mode 7) scale rows above lateral line at dorsal-fin origin. Phylogenetic hypothesis about its relationships among the Characidae is also presented and commented.


Introduction
Moenkhausia Eigenmann, with 76 valid species, is a species-rich genus of the Characidae (sensu Mirande, 2010).Together with Astyanax Baird & Girard, Hemigrammus Gill, and Hyphessobrycon Durbin, they represent around 35% of characid species.Moenkhausia species are widespread in the Neotropical cis-Andean river basins, and its largest diversity is in the Amazon and Guyana basins (Lima et al., 2003;Eschmeyer, 2014).The group includes small (e.g., M. newtoni Travassos; maximum length: 27.0 mm Standard Length -SL) and relatively large species (e.g., M. tridentata Holly; 118.1 mm SL), although the average size of species is around 60 mm SL, with broad range in overall body shape and color pattern.
In spite of Moenkhausia being regarded as a nonmonophyletic genus (Mirande, 2010;Mariguela et al., 2013), and in the absence of a phylogenetic analysis available at the moment, the genus is still recognized in a traditional combination of characters presented by Eigenmann (1917), e.g., caudal fin at least partly covered with small scales; lateral line complete; second suborbital (third infraorbital sensu Weitzman, 1962) leaving a naked area dorsal to the lower limb of preopercle; at least five teeth in the inner row of the premaxillary.Moreover, Eigenmann (1917) was the only author to present a unique complete taxonomic revision for the genus, at that moment with 29 species.
Approximately one-half of the species ascribed to Moenkhausia were described in the first half of the 20 th century.Many of these were poorly diagnosed and little is known about their distributions.Within this context, we herein provide a redescription of Moenkhausia doceana (Steindachner), a taxon distributed in the coastal drainages of Espírito Santo, Minas Gerais, and Bahia states (Northeastern Mata Atlântica ecoregion sensu Abell et al., 2008) to help in clarifying the taxonomic status within the genus.Comments about its relationships in the Characidae are also presented and commented.

Material and Methods
Measurements and counts were taken as described by Fink & Weitzman (1974) and Carvalho et al. (2010).Measurements were made with a digital caliper to the nearest 0.05 mm on the left side of the specimen whenever possible, and are presented as percents of standard length (SL), except subunits of the head, which are given as percents of head length (HL).In the description, counts of non-type specimens are followed by their frequency in parentheses, and values between brackets indicate counts of the syntypes.Counts of vertebrae, supraneurals, gill-rakers on the first branquial arch, branchiostegal rays, procurrent caudal-fin rays, dentary teeth, and number of cusps were taken from four c&s specimens prepared according to Taylor & Van Dyke (1985).Vertebral count includes the four vertebrae in the Weberian apparatus and also the fused PU1+U1 of the caudal region as a single element.The pattern of circuli and radii was defined on scales sampled from the region between the lateral line and the insertion of pelvicfin.Comparisons and data of Moenkhausia species not available for examination were taken from the literature (original descriptions).In "Material examined" catalog numbers are followed by the total number of specimens, number of specimens measured and counted in parentheses, and SL range of all specimens (including c&s specimens, if any) of the lot, when possible.Stomach contents of some preserved specimens in alcohol solution 70 o were analyzed.Institutional abbreviations follow Reis et al. (2003), with addition of CIUFES, Coleção Ictiológica da Universidade Federal do Espírito Santo, Vitória; MBML, Museu de Biologia Professor Mello Leitão, Santa Teresa; UFBA, Universidade Federal da Bahia, Salvador; UFRGS, Departamento de Zoologia, Universidade Federal do Rio Grande do Sul, Porto Alegre; ZMA, Zoologisch Museum Amsterdam, now in RMNH, National Natuurhistorisch Museum, The Naturalis Biodiversity Center, Leiden.
A phylogenetic analysis was performed using TNT software (Goloboff et al., 2008), adding Moenkhausia doceana to the matrix of Mirande (2010) and modified by Carvalho et al. (2014).The analysis included implied weighting, following the same procedures described by Mirande (2009Mirande ( , 2010)), and 21 values of "k" were used under each of the weighting schemes.Character states for M. doceana are given in Table 1.The numbers for each character follow Mirande (2010).(Steindachner, 1877) Figs.
Diagnosis.Description.Morphometric data are summarized in Table 2. Body compressed, moderately long and high, greatest body depth at vertical through dorsal-fin origin.Dorsal profile of head convex from tip of upper jaw to vertical through anterior nostril; slightly concave or straight from that point to tip of supraoccipital spine.Dorsal profile of body slightly convex from posterior tip of supraoccipital spine to base of first dorsalfin ray, and straight that point to adipose-fin origin.Ventral profile of body convex from tip of lower jaw to pelvic-fin origin, straight or slightly convex from that point to anal-fin origin, and straight and posterodorsally slanted along of analfin base.Dorsal and ventral profile of caudal peduncle straight to slightly concave.Mouth terminal, premaxillary and dentary approximately the same size.Maxilla extending posteroventrally to first onethird of orbit, almost reaching tip of second infraorbital, approximately at 45 degrees angle relative to longitudinal axis of body.Main axis of maxilla straight, with approximately same width along entire length.Nostrils close to each other, anterior opening small and circular, posterior opening twice in size and reniform.Nostrils separated by skin flap when adpressed, almost covering the posterior nostril.Frontals not united anteriorly, with a triangle-shaped fontanel; parietal fontanel 00110010?1 0011000100 0001100001 0000100001 0000011a00 0a00000000 0000000011 ?010000000 0000000110 0101000010 0010000001 1000000100 0100011010 00011101a0 001?000100 1010000000 0000000101 0001000110 0101000101 0001100000 0111000010 0100000101 0100000100 1001000000 0000000001 0101000100 0001110001 1000010000 0000111100 0000010101 0000101110 0000010011 2100000110 0001110000 1100000000 00?0?00??? ????? Table 1.Character states of Moenkhausia doceana.Character list is the same of Mirande (2010); polymorphisms [01] are represented as "a".large, extending from epiphyseal bar to supraoccipital spine.Eyes relatively large, without adipose eyelid.Infraorbital bones complete, with six elements (Fig. 4).Laterosensory canal from first to sixth infraorbital close to inner margin of orbital rim.Third infraorbital largest, approximately twice the size of others (except second), with inferior margin slightly straight (Fig. 4), not contacting the laterosensory canal of preopercle ventrolaterally.
Scales cycloid, with few radii (2-6), relatively small; circuli marked anteriorly and marginally (dorsal and ventral).Lateral line complete, extending from the superior portion of opercular opening to beginning of caudal fin with 34(2), 35(31), 36(29), 37( 2  Color in alcohol.Overall ground coloration yellowish, with light brown thin stripe extending longitudinally along lateral line from vertical through dorsal-fin origin to caudal peduncle.Head brownish dorsally, paler towards sides of head.Dark chromatophores concentrated on distal margin of scales resulting in reticulated pattern.Mid-dorsal region darker than flanks.Humeral region with horizontally rounded dark spot immediately above lateral-line scales, extending about two scales vertically and 4-6 scales horizontally.A second faint blotch behind humeral spot, comma shaped.Area above hypural plate with faint dark spot, almost triangle shaped.First rays of pelvic and anal fins with dark chromatophores, resulting in darker fin border.Dorsal fin with scattered dark chromatophores, more concentrated on anterior one-half.Anal fin with scattered dark chromatophores.Adipose-fin contour with dark chromatophores.Remaining fins hyaline on tips, with scattered dark chromatophores between unbranched rays (Fig. 2).

Color in life.
The following description is based on the examination of freshly specimens recently caught along northern Espírito Santo and southern Bahia rivers.Ground color pale yellow to silver gray, darker dorsally.Sides of body somewhat silver colored anteriorly to light red posteriorly.Longitudinal inconspicuous brilliant stripe at level of lateral line, silvery colored in some specimens.Humeral region with a faint horizontally rounded spot, followed by a second comma shaped faint blotch.Eyes yellowish to whitish.Opercle and preopercle region silver colored; fins yellowish to translucent (Fig. 3).A faint brownish spot, almost triangle shaped on caudal peduncle.
Sexual dimorphism.Bony hooks on anal and pelvic fins, and also anal-fin profile distinguish males from females in Moenkhausia doceana.Mature males with very small bony hooks on the segments of the last unbranched and all branched anal-fin rays (one pair of bony hooks on posterior surface of hemitrichia), absents in females.Males with anal-fin distal margin slightly straight (Fig. 2a) while females with anal-fin distal margin falcate anteriorly (Fig. 2b).Gill glands (sensu Burns & Weitzman, 1996) were not found macroscopically on first gill arch on both sexes.
Distribution.Moenkhausia doceana occurs along coastal river systems, with northern limits corresponding to the rio João de Tiba, on extreme southern Bahia river basins.The species is recorded until southern limits at the rio Riacho, a small coastal basin south of rio Doce in Espírito Santo State, and to the West in the middle rio Doce lake systems, rio Doce basin (Fig. 6).Known populations of M. doceana inhabit areas of mild relief, as in lakes of the rio Doce valley and along coastal drainages between Espírito Santo and southern Bahia states.The western portion of its distribution is within Coastal Tablelands area, a wide region with elevations usually not passing 150 m, coinciding with the Cenozoic sediments of the Barreiras Group, well seen along the whole coastal distributional area.Despite its range distribution, no significant morphological and meristic differences were found among M. doceana populations, suggesting that the species corresponds to a single taxon in all coastal drainages where it occurs.Regarding global biogeography regionalization of freshwater systems, the pattern of distribution of M. doceana fits the Northeastern Mata Atlântica ecoregion (sensu Abell et al., 2008).Popular name.Moenkhausia doceana is known as lambari (Lima et al., 2003) or piaba, in northern Espírito Santo and southern Bahia states.

Discussion
Tetragonopterus doceanus was transferred to Moenkhausia doceana by Eigenmann (1910:437).The specific epithet "doceanus" is a reference to the rio Doce, primarily type locality of the species.Moenkhausia doceana has the diagnostic features for the genus proposed by Eigenmann (1917) and herein we keep with this traditional definition, pending a more comprehensive phylogenetic context.
Traditionally, Moenkhausia doceana has been considered a member of M. chrysargyrea species group since Géry (1977), a group of species with seven or more scales above lateral line to dorsal-fin origin, five or more scales below the lateral line to pelvic-fin origin, and a relatively deep body.This group originally included 12 species: M. chrysargyrea (Günther), M. comma Eigenmann, M. doceana, M. eigenmanni Géry, M. jamesi, M. justae, M. metae Eigenmann, M. miangi Steindachner, M. naponis Böhlke, M. pittieri Eigenmann, M. surinamensis Géry, and M. tridentata (Géry, 1977: 446-447).Subsequently, more species can be assigned to the M. chrysargyrea group: M. dasalmas Bertaco, Jerep & Carvalho, M. dorsinuda, M. levidorsa Moenkhausia doceana is very similar to M. margitae, as mentioned by Zarske & Géry (2001), based on the body form and color pattern, with a horizontally elongate black humeral spot.It differs of M. margitae by presenting 4-7 maxillary teeth and the caudal peduncle with a faint dark spot in the hypural plate area (vs.1-2 maxillary teeth and no marks dark over the caudal peduncle).
In the Northeastern Mata Atlântica ecorregion, three Moenkhausia species are found: M. costae (Steindachner), M. diamantina Benine, Castro & Santos, and M. doceana.Moenkhausia doceana differs from M. costae mainly by the hyaline caudal fin (vs. a conspicuous black stripe extending from anal-fin origin to tip caudal-fin upper lobe); from M. diamantina by having anal fin with 29 or more branched rays (vs.anal fin with 28 or less branched rays in M. diamantina).
In recent descriptions of Moenkhausia species, there are usually comments on putative relationships of the new species described with its congeners; and this information is primarily based on one or a few shared characters among the taxa based on groups of Géry (1977).Although there are few published morphological hypotheses testing the relationships between Characidae species, we herein address some tests, in order to contribute to phylogenetic knowledge within the group.Following the protocol of Mirande (2010) for the Characidae, we tentatively discuss the results for M. doceana in this approach.
Phylogenetic placement of Moenkhausia doceana in Mirande's (2010) (Steindachner), plus M. doceana herein added).Mariguela et al. (2013) presented a molecular phylogenetic analysis for some Moenkhausia species (29 of 75 species, not including M. doceana), and recognized some monophyletic clades, but their conclusions also reinforce a non-monophyletic genus, and an extensive revision of the whole group is required.Eigenmann (1917) stated Moenkhausia as distinct from Tetragonopterus Cuvier regarding the lateral line direction (i.e., line straight vs. slightly curved downwards).Reis (2003) restricted Tetragonopterus to two species (T.argenteus and T. chalceus Spix & Agassiz), and more recently new species have been proposed (e.g., Melo et al., 2011;Silva & Benine, 2011;Silva et al., 2013).Melo et al. (2011) discussed the presence of three supraneurals and one branched laterosensory canal on the sixth infraorbital bone as putative synapomorphies for Tetragonopterus.This last character was also used by Mirande (2010, char. 76).Moenkhausia doceana has 3-4 supraneurals (mode 4) and no branched laterosensory canal on sixth infraorbital, and in this way the species does not fit in a monoplyletic Tetragonopterus clade (sensu Melo et al., 2011).
Three lots of Moenkhausia doceana (MZUSP 1404, 1, 79.1 mm SL;MZUSP 1625, 14, 64.3-79.5 mm SL;and MZUSP 16374, 5, 62.0-74.9mm SL) were collected by E. Garbe in Porto Cachoeiro locality, Espírito Santo State.Porto Cachoeiro was the name given to Santa Leopoldina between 1890 and 1911.This area is drained by rio Santa Maria da Vitória basin, a costal river drainage in northeastern Espírito Santo.Several collecting efforts were directed to the whole area, but no record of this species was obtained.Thus, as those are very ancient records and as we do not have any recent record of M. doceana for the rio Santa Maria da Vitória basin, we opted not to include this river basin in the distributional area of the species.
A reappraisal of very old described species should be encouraged today.In a study such as the one presented herein, we had the chance to increment the diagnosis for such a taxon, improve the knowledge on its distribution, and provide phylogenetic information, primordial for several other scientific areas.As mentioned above, approximately one-half of Moenkhausia species were described before 1950, and many of these were not clearly diagnosed.Indeed, the desired condition is a complete taxonomic revision of all these taxa.Nowadays, for "catch-all" genera (sensu Bertaco & Lucinda, 2006) such as Astyanax (ca.140 species), Hemigrammus (54 species), Hyphessobrycon (132 species), and Moenkhausia (75 species) (Eschmeyer, 2014), it is very difficult to assess their taxonomic compositions in a single work including all species of each genera, thus redescriptions are encouraged for many of these species.
As presented by Malabarba et al. (2012) and Weiss et al. (2012), the conserved form within the Characidae, a long period of evolution of the group and its great diversity are the most challenging factors for understanding the relationships among small characids.Characters should be continuously assessed to address the significance in delimiting groups within the Characidae, mainly in the Tetragonopterinae (sensu Mirande, 2010) and in the informal clades of Mirande (2010) (e.g., Bryconops clade, Bramacharax clade, Pseudochalceus clade, Hyphessobrycon luetkenii clade, Astyanax paris clade, Astyanax clade, Bryconamericus sclerioparius clade), as many features are relatively widespread among these small characids.Taxonomic changes in species-rich genera as Moenkhausia, grounded in phylogenetic analysis, are necessary and expected in the next years, according to hypotheses of monophyletic groups.

Fig. 6 .
Fig. 6.Distribution of Moenkhausia doceana in Northeastern Mata Atlântica ecoregion.Each mark may represent more than one locality.