Redescription of Hyphessobrycon flammeus Myers, 1924 (Ostariophysi: Characidae), a threatened species from Brazil

species, H. flammeus Myers, is redescribed. Diagnostic characters of the species are two vertically elongated humeral spots, no caudal peduncle blotch, 5-8 maxillary teeth, caudal fin hyaline, and longitudinal dark stripe of the body absent. Sexual dimorphism is present, with males being more colored than females and having bony hooks in the anal and pelvic fins, which are dark in their terminal portions. Comments about its occurrence in the upper rio Tiete drainage (upper rio Parana basin), its conservation status, and the phylogenetic position into Characidae context are also presented.Uma das mais coloridas e ameacadas especies de


Introduction
Hyphessobrycon Durbin is one of the richest genus of Characidae, with more than 130 species, many described in this century (e.g., Carvalho & Bertaco, 2006). Besides this diversity, several species need to be revised and compared with its congeners and with all other small Characidae, because to date they fail to be clearly and unequivocally distinguished from other congeners. The boundary of diagnostic characteristics for the genus is wide (see Durbin in Eigenmann, 1908;Eigenmann, 1917Eigenmann, , 1918, and some species present other characteristics added to the genus after Eigenmann (1917Eigenmann ( , 1918) (e.g., complete lateral line, absent adipose fin) that should be analyzed in a more inclusive context.
In Brazil, there are three threatened species of Hyphessobrycon: Hyphessobrycon duragenys Ellis, H. flammeus Myers, and H. taurocephalus Ellis (Lima & Moreira, 2008). All these species are poorly described, their distribution is uncertain, and limited data are available in the literature about biology/ecology and distribution.
Hyphessobrycon flammeus is a small, brightly colored tetra, which is very appreciated in aquarium trade. The species was described by Myers (1924) from some aquarium specimens that had been identified as H. bifasciatus Ellis (known as 'red Tetragonopterus from Rio'). Since its original description, little taxonomic information was added for the taxon in literature. As mentioned above, H. flammeus composes the list of Brazilian freshwater fish endangered species (Machado et al., 2005;Lima & Moreira, 2008). This situation requires efforts to understand its identity, geographic distribution, and ecological/biological data, necessary for the establishment of public policies to its effective conservation.
Herein we present a redescription of H. flammeus, with details about its geographical distribution and comments about its phylogenetic relationships in the Characidae context (sensu Mirande, 2010).

Material and Methods
Measurements and counts followed Fink & Weitzman (1974), , and Carvalho et al. (2010). Measurements were made with a caliper rule to the nearest 0.05 mm on the left side of the specimen whenever possible, and are presented as percents of standard length (SL) or head length (HL). In the description, counts are followed by their frequency in parentheses, and asterisk(s) indicates the count of the syntype(s). In the list of examined material, the number of all specimens in the lot is followed by the number of those examined and cleared and stained (c&s) individuals, if any. Counts for vertebrae, supraneurals, gill-rakers on the first branquial arch, branchiostegal rays, procurrent caudalfin rays, and small dentary teeth were taken from six c&s specimens prepared according to Taylor & Van Dyke (1985). Vertebral count included the four vertebrae in the Weberian apparatus and 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 pelvic-fin. Comparisons and data of species not available for examination were taken from the literature (original descriptions). Catalog numbers are followed by the total number of specimens, number of specimens measured and counted in parentheses, and SL range of all specimens of the lot. Comparative material examined included also those material listed in Carvalho & Langeani (2013).
A phylogenetic analysis was performed, using TNT software (Goloboff et al., 2008), adding Hyphessobrycon flammeus to the matrix of Mirande (2010) and modified by Malabarba et al. (2012). 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 H. flammeus are given in Table 1. The numbers given for the characters followed Mirande (2010). Cytogenetic data (characters 361-365) were of Arefjev (1990). Myers, 1924 Figs. 1-5
Central median cusp of all teeth longer than remaining lateral cusps; cusp tips slightly curved inward on dentary teeth, and relatively straight on premaxillary teeth.
supraoccipital spine. Dorsal profile of body slightly convex from posterior tip of supraoccipital spine to base of last dorsal-fin ray, and straight to adipose-fin origin; last dorsalfin ray at vertical through of anal-fin base. 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/or subtly rounded along anal-fin base. Dorsal and ventral profiles of caudal peduncle slightly straight. Eyes relatively large compared with head, without distinct adipose eyelid. Lower jaw slightly longer than upper jaw, mouth slightly subterminal. Maxilla extending posteriorly surpassing anterior margin of orbit to vertical through crystalline lens anterior margin, slightly curved, aligned approximately at 45 degrees angle relative to longitudinal axis of body. Nostrils close to each other, anterior opening small and circular, posterior one twice in size and slightly reniform or elongate. Nostrils separated by skin flap. Nasal bone absent. Frontals separated anteriorly, with wide fontanel; parietal fontanel large, extending from epiphyseal bar to supraoccipital spine, slightly narrowed anteriorly. Infraorbital series with four or five elements (probably fifth and sixth, when present, fusioned). Laterosensorial canal of first infraorbital absent, from second to fourth canal close to inner margin of orbital rim. Third infraorbital largest, double size compared to other (in length and depth) and contacting laterosensory canal of preopercle ventrolaterally.
Premaxillary teeth in two rows: outer row with 1*(12) or 2(46) tricuspid teeth; inner row with 5*(57) or 6(1) pentacuspid teeth. Dentary with 4*(59) or 5(1) large, tri-to  Table 2. Morphometric data for Hyphessobrycon flammeus. SD = standard deviation, including the syntypes data (N = 2); range is of non-types specimens; N = number of specimens, not including the syntypes. more densely concentrated from snout to the supraoccipital. Second and third infraorbitals and upper region of opercular apparatus denser chromatophores, and yellowish adjacent areas. Small chromatophores scattered on the jaws. Two conspicuous vertically elongated humeral spots, extending from the dorsal portion to the pectoral fin, positioned over three to four vertical series of scales above the lateral line and four to five below it, and vertically extending over two to four horizontal series of scales, more intense in the middle of the humeral spot; both spots are separated by two to three horizontal scales. Abdominal region yellowish, with few scattered chromatophores. Lateral side of the body scattered melanophores, dorsal portion with a reticulated pattern on the posterior margin of its scales. Midlateral body stripe absents.
All fins hyaline or slightly dark (see more details for males in sexual dimorphism).

Color in life.
Overall, body with an intense reddish color (hence the name flammeus, from latin, red -flame-colored).
More intense concentration of erythrophores between verticals from the dorsal and/or pelvic-fin to anal-fin end. Distribution of melanophores on its head, flank and fins similar to the one described in alcohol coloration. Dorsal and dorsolateral regions of body rosaceous and orangish. Ventral area of its head up to its posterior humeral spot, including the abdominal region, slightly grayish to yellowish. Sometimes, the upper area of its head up to its first humeral spot with iridescent blue hues. All fins reddish, no pigmentation on the middle caudal-fin rays; caudal and anal fins with a more intense color. Males with black pelvic and anal fins tips and whitish dorsal fin (vs. absent in females) (Fig. 4).

Sexual dimorphism.
Males of Hyphessobrycon flammeus present bony hooks in the anal and pelvic fins (Fig. 5) (vs. absent in females). Small, simple bony hooks in the anal fin, extending from the last unbranched ray to the last branched rays, i.e., in all fin rays (Fig. 5a for the first bony hooks in the anal fin); pelvic fin with hooks in the first two or three branched rays (Fig. 5b). Distal portion of its anal fin slightly straight in males (vs. anteriorly falcate in females) (Fig. 2).
During reproduction, the female deposits around 200 to 330 oocytes on rocks, plants, or submerged debris; after that, the male releases the sperm for fecundation. The eggs hatch in approximately 2-3 days (Miranda et al., 2012). Further ecological/biological information can be found in Myers (1924Myers ( , 1945, Lima & Moreira (2008) and Oyakawa et al. (2009). On the Wide World Web, there is plenty of information shared among aquarists about behavior, reproduction, and many other biological characteristics of H. flammeus, including information on keeping and reproducing them in captivity.
Conservation remarks. Hyphessobrycon flammeus has been in the Brazilian list of threatened fish species since 2004 (Diário Oficial da União, 2004), category EN-A2ace; B2ab(iii) (i.e., endangered species). However, after the last evaluation conducted by ICMBio (Instituto Chico Mendes de Conservação da Biodiversidade) (in 2012, unpublished data) the category EN will be maintained, but the criteria will be changed.
Males normally smaller than females, but present a bright reddish color, with black tips on pelvic and anal fins. Darkish dorsal fin in the middle portion and whitish on the tip in both males and females. Gill glands (Burns & Weitzman, 1996) were not found macroscopically on first gill arch on both sexes.

Distribution.
Hyphessobrycon flammeus has occurrence in streams and coastal rivers of Rio de Janeiro State, in Guanabara bay basin, middle rio Paraíba do Sul basin and rio Guandu basin. In the upper rio Tietê drainage (upper rio Paraná basin, São Paulo State) it is found around of the metropolitan region of São Paulo city (Fig. 6).

Discussion
Hyphessobrycon flammeus is a small-sized species from a non-monophyletic and heterogeneous genus (cf. Zanata & Camelier, 2011, Ingenito et al., 2013. The artificial classification presented by Géry (1977) is a convenience to group the species in the genus according to the color pattern, but not expressing the common ancestry of all taxa currently housed in Hyphessobrycon.
The combination of diagnostic characteristics from H. flammeus, i.e., 5-8 teeth in maxilla, two humeral spots and no caudal peduncle spot, associated with the bright reddish color of its body seems to be unique among the Hyphessobrycon species. Due to this color pattern, it is a very appreciated species in aquarium trade.
Some characters presented by H. flammeus, e.g., incomplete lateral line, infraorbital series with fusioned elements, small size (up to 26.1 mm SL), absent nasal bone, are reductive characters which characterize miniature species (sensu Weitzman & Vari, 1988). The reductive characters can influence its position in the cladogram far from other Hyphessobrycon, which do not normally present these conditions. As presented by Mattox et al. (2013), reductive characters are potential sources of problem in phylogenetic hypothesis, because they could be derived from different events of miniaturization, resulting in false synapomorphies to clades or autapomorphies to taxa.
The phylogenetic analysis showed that Hyphessobrycon flammeus is not close to H. compressus, the type species of genus. In this present analysis, the relationship for H. compressus is (Hyphessobrycon compressus (Hemigrammus unilineatus, Pristella maxillaris) (Hyphessobrycon pulchripinnis (Hyphessobrycon eques, Hyphessobrycon socolofi))). Although it is clear the polyphyletism of Hyphessobrycon and the removal necessity of many species currently housed in this genus, taxonomic changes involving all taxa are expected only after a careful analysis including most species of the genus. So, we keep the species in the genus until these changes are implemented.
Distribution of Hyphessobrycon flammeus was mentioned in the literature, until around 2007, as restricted to the coastal rivers of Rio de Janeiro State . Lima & Moreira (2008) expanded the distribution to São Paulo State in upper rio Tietê drainages, discussing the uncertainty of being autochthonous or allochthonous in the upper rio Paraná basin. Despite these two different populations, coastal and upper rio Paraná, no significant differences between them were found. Therefore, conservation actions for H. flammeus should mainly prioritize the protection of its natural habitats, or allochthonous, and a more strict control of aquarium trade. The occurrence of threatened species in the most populous and industrial area of Brazil (Rio de Janeiro and São Paulo cities) requires additional efforts for the maintenance and perpetuation of these taxa in the Neotropical region.
The first record of H. flammeus to upper rio Tietê basin is from 1977 (ZUEC 4439). Natural occurrence of the same species in two isolated basins (i.e., coastal drainages and upper rio Tietê) has been widely documented in the literature since Langeani (1989), as well as by Ribeiro et al. (2006), Serra et al., (2007), Silva et al. (2010), and Marceniuk et al. (2011). Despite this evidence, this does not seem to be the case for the H. flammeus distribution.
The recent record of Hyphessobrycon flammeus in upper rio Tietê drainage strongly suggests that it is, very likely, arising from the introduction by aquarium trade. Some facts which support this hypothesis are: i. the species has always been common in the aquarium trade, and São Paulo city is an important center for that; ii. historical records of H. flammeus in museum collections of specimens from the rio Tietê drainages, a historically well-sampled region, are very recent, scarce and punctual around São Paulo city metropolitan area, and absent for example, from the Serra de Paranapiacaba (rio Pinheiro drainage) in pristine areas; iii. relative abundance of H. flammeus in recent samplings are restricted to streams with some traces of degradation and near São Paulo city metropolitan area; iv. sharing species among adjacent drainages are more commonly restricted to headwaters of adjacent areas, in relatively pristine rivers/streams; v. there is a relatively large gap between Rio de Janeiro drainages and the rio Tietê drainages without occurrence of H. flammeus, a relatively well-sampled area. However, in order to test this hypothesis, a molecular analysis would provide more data about differences (or not) and time of separation between the two populations.
The first record of H. flammeus in a Brazilian collection dates from 1954 (MNRJ 8795, Rio de Janeiro, Guanabara bay basin). After this record, few lots and individuals were added, mainly in MNRJ, evidencing that populations of H. flammeus in its natural area is very rare. The last record from Rio de Janeiro State is of 1972. Most records, however, date from early 21 st century for São Paulo State. This paradox of few records in scientific collections of a relatively common species in the aquarium trade is also found in some other species, such as Hemigrammus erythrozonus Durbin, Hyphessobrycon roseus (Géry), H. takasei Géry, Inpaichthys kerri Géry & Junk, Tucanoichthys tucano Géry & Römer, to mention some. Surprisingly, on the other hand, these species are frequently found, particularly H. flammeus, in aquarium stores in Brazil and foreign countries. Many of this species are bred and kept in aquarium.
Due to its bright color and its easy maintenance in aquarium, H. flammeus is very appreciated by aquarists, exported to several countries in Europe and the United States. Commercialization of species, associated with pollution, urbanization, agricultural and industrial activities, damming of lotic courses, substitution of marginal and riparian vegetation, introduction of species (e.g., tilapia and black-bass), are the main deleterious anthropic effects which threaten its natural occurrence and abundance in pristine environments.