Hyphessobrycon brumado : a new characid fish ( Ostariophysi : Characiformes ) from the upper rio de Contas drainage , Chapada Diamantina , Bahia , Brazil

Hyphessobrycon Durbin is one of the most speciose, widespread and taxonomically poorly known genera of the family Characidae, with more than 120 valid species including a series of recently described ones, distributed from southern Mexico to río de La Plata in Argentina (e.g., Carvalho & Bertaco, 2006; Bertaco et al., 2007; Benine & Lopes, 2008; Carvalho et al., 2008; Garzía-Alzate et al., 2010a, 2010b; Miquelarena & López, 2010). The recognition of groups of species within Hyphessobrycon is based primarily on similarities of color patterns and a hypothesis of its intrarelationships is currently unavailable, except for the rosy tetra clade proposed as monophyletic by Weitzman & Palmer (1997). Ten species of Hyphessobrycon are currently known from northeastern Brazilian coastal rivers, distributed between Bahia and Ceará States. Four of them were described for drainages in Bahia: H. itaparicensis Lima & Costa from a small stream in Ilha de Itaparica, H. negodagua Lima & Gerhard from rio Paraguaçu, H. parvellus Ellis from rio Catu and rio Itapicuru, and H. vinaceus Bertaco, Malabarba & Dergam from rio Pardo basin. The remaining northeastern species are somewhat more widespread or occurs just outside the Bahia State, and include H. bifasciatus Ellis from eastern Brazilian rivers, including the south of the Bahia State, H. iheringi Fowler, H. latus Fowler, and H. piabinhas Fowler from Fortaleza, Ceará State, and H. micropterus (Eigenmann) and H. santae (Eigenmann) from the rio São Francisco basin. Recent collecting efforts in the rio de Contas basin revealed various undescribed fish species, especially from small tributaries of upper portion of the drainage, including a new species of Hyphessobrycon described herein.


Introduction
Hyphessobrycon Durbin is one of the most speciose, widespread and taxonomically poorly known genera of the family Characidae, with more than 120 valid species including a series of recently described ones, distributed from southern Mexico to río de La Plata in Argentina (e.g., Carvalho & Bertaco, 2006;Bertaco et al., 2007;Benine & Lopes, 2008;Carvalho et al., 2008;Garzía-Alzate et al., 2010a, 2010b;Miquelarena & López, 2010).The recognition of groups of species within Hyphessobrycon is based primarily on similarities of color patterns and a hypothesis of its intrarelationships is currently unavailable, except for the rosy tetra clade proposed as monophyletic by Weitzman & Palmer (1997).Ten species of Hyphessobrycon are currently known from northeastern Brazilian coastal rivers, distributed between Bahia and Ceará States.Four of them were described for drainages in Bahia: H. itaparicensis (Eigenmann) and H. santae (Eigenmann) from the rio São Francisco basin.Recent collecting efforts in the rio de Contas basin revealed various undescribed fish species, especially from small tributaries of upper portion of the drainage, including a new species of Hyphessobrycon described herein.

Material and Methods
Counts and measurements were taken according to Fink & Weitzman (1974) and Menezes & Weitzman (1990), except for number of horizontal scale rows below lateral line which were counted to the pelvic-fin insertion.Upper scales count of transverse series represents the number of rows of scales between median dorsal row and the lateral line, not including the scale on the median dorsal row or the small scale just below dorsal-fin rays insertion.In the description, the frequency of each count is given in parentheses after the respective count.An asterisk indicates counts of the holotype.Counts of vertebrae, supraneurals, procurrent caudal-fin rays, branchiostegal rays, gill-rakers, dentary teeth and number of tooth cusps were taken only from cleared and stained paratypes (c&s), prepared according to the method of Taylor & van Dyke (1985).Dentary and premaxillary bones of one cleared and stained specimen were cleaned from soft tissues for scanning electron micrographs (SEM) images by a short (less than 10 min) immersion in weak (less than 1%) sodium hypochlorite solution and after that air-dried.Vertebrae of the Weberian apparatus were counted as four elements, included in the vertebral counts, and the fused PU1+U1 of the caudal region as a single element.Pattern of circuli and radii was defined on scales sampled from the region between the lateral line and the insertion of the dorsal-fin.Various specimens were dissected for sex confirmation.Institutional abbreviations follow Ferraris (2007), with the inclusion of Universidade Federal da Bahia, Salvador, Bahia, Brazil (UFBA).Specimens utilized for comparative analysis are listed under 'Comparative material' and other comparisons provided elsewhere were based on the literature information (Eigenmann, 1918;Fowler, 1941Fowler, , 1948;;Géry 1977;Lima & Gerhard, 2001).
Scales cycloid; circuli absent on posterior margin of scales; none or few slightly poorly developed radii extending to posterior margin of scales.Lateral line incomplete, with 5(1), 6(2), 7(7), 8(10), or 9*(1) perforated Fig. 2. Hyphessobrycon brumado, paratype, just after fixation, male, UFBA 4341, 29.6 mm SL.Color in alcohol.Overall ground color yellowish (Figs. 1 and  3).Dark chromatophores densely concentrated on dorsal surface of head from upper lip to supraoccipital spine.Infraorbitals and opercle retaining guanine, clear on most of its area, with few relatively large dark chromatophores over area close to orbit and posterior to dorsal portion of eye.Small, dark chromatophores present over anterior half to two-thirds of maxilla.Ventral portion of head less pigmented than dorsal portion; lower lip darkened and portion of head anterior to orbit with scattered dark chromatophores, more concentrated on its median area.
Scales of dorsal portion of body with dark chromatophores, more concentrated along its posterior margin resulting in mild reticulate pattern; reticulate pattern restricted to scales dorsal body half.Humeral region without humeral spot.Dark and relatively broad stripe extends from rear of eye to caudal peduncle; stripe more evident posterior to humeral region and enlarged at end of caudal peduncle, forming rough rounded caudal blotch.Males somewhat darker on posterior portion of body and with caudal blotch more inconspicuous than in females.Caudal blotch extending to median caudal-fin rays, reaching up to12 rays in males and 6-7 in females.Abdominal region without dark chromatophores.
All fin-rays slightly darkened by presence of dark chromatophores scattered over borders of rays and interradial membranes.Pelvic fin somewhat clearer.Caudal fin somewhat darker, with dark chromatophores on distal portion of rays, mainly on central rays, more evident on mature males.Adipose fin slightly darkened by small dark chromatophores.
Color just after fixation.Overall body coloration orange-to reddish (Fig. 2).Borders of scales on dorsal half of body darkened, forming mild reticulate pattern.Dark, elongated and relatively broad stripe extends from vertical around posterior half of anal fin to median caudal-fin rays; stripe enlarged at end of caudal peduncle, forming roughly rounded caudal blotch.All fins orange-to reddish with scattered dark chromatophores and borders relatively clearer.Males apparently more colored than females.
Sexual dimorphism.The unique dimorphic feature observed externally is related to color pattern.Some males have the lateral stripe broader, the blotch on caudal peduncle with inconspicuous border, and a large number of median caudalfin rays darkened (up to 12) (Fig. 2).Females possess a narrower lateral stripe, a more conspicuous rounded caudal blotch and dark pigmentation of caudal fin usually restricted to six or seven median rays (Fig. 3).These dimorphic traits are not conspicuous in the majority of specimens examined and are much less evident than the dimorphic coloration described for Hyphessobrycon negodagua (Lima & Gerhard, 2001: figs. 2-3).

Geographic distribution and ecological notes.
Hyphessobrycon brumado is known from rio Brumado, tributary of the rio de Contas, a coastal drainage of eastern Brazil (Fig. 5).The species was captured in streams characterized by relatively rapid water current, running over rocky and sandy bottoms at elevate altitudes (971 and 1.048 m a.s.l.) (Fig. 6).The riparian vegetation is formed by grass, shrubs and trees.Fish species collected with H. brumado are Astyanax aff.lacustris, Gymnotus aff.carapo, Hypostomus sp., Parotocinclus jimi, Poecilia reticulata, Rhamdia aff.quelen, and Trichomycterus sp.
The analysis of stomach contents of three specimens revealed presence of filamentous algae, fragments of vascular plants, adults and two distinct larvae of Diptera (Chironomidae and Simuliidae), larvae of Trichoptera, adult of Formicidae, Aranae, and fragments of unidentified arthropods.Presence of allochthonous arthropods and other autochthonous items suggests that Hyphessobrycon brumado is an omnivorous species with a considerable plasticity on its diet.The broad range of food items of this species diet also suggests that it explores the resources available along the entire water column.

Popular name. Piaba.
Etymology.Named after Brumado, the river where the species is found.A noun in apposition.

Discussion
Hyphessobrycon brumado shares a series of characters with H. negodagua, described for a headwater of rio Paraguaçu, and H. parvellus, described from rio Catu (rio Pojuca drainage).The three species are from coastal drainages of Bahia State and could be interpreted as putatively closely related on the basis of its elongated body, reduced layer of musculature between first and second ribs (more evident on H. parvellus), absence of humeral spot, absence of a well defined caudal spot (mainly in males), together with sexually dimorphic coloration of caudal region.Lima & Gerhard (2001) pointed out that the color pattern is a good starting point to elucidate the complex systematic of Hyphessobrycon and related genera, and a comparison of these traits for the three cited species seems pertinent.
The dimorphic color pattern of H. negodagua was described in detail by Lima & Gerhard (2001) According to Lima & Gerhard (2001), one of the main differences between H. negodagua and H. parvellus is related to the absence of adipose fin in the former.However, examination of specimens tentatively identified as H. parvellus recently collected in various coastal drainages of Bahia State has revealed presence of adipose fin as polimorphic, mainly on specimens of rio Paraguaçu drainage.A more precise definition of H. parvellus and the clear limit between it and H. negodagua depends on an extensive examination of these two species, a task under way by one of the authors (AMZ).
Recent collecting efforts on several coastal drainages on Bahia State has indicated that H. brumado and H. negodagua are apparently restricted to headwaters of rio de Contas and rio Paraguaçu, respectively, while H. parvellus is more broadly distributed, from rio Real on the extreme north Bahia to rio de Contas, on central portion of Bahia State.Similarly to rio Paraguaçu, the rio de Contas has a substantial endemic component on its ichthyofauna, although even less known taxonomically.Species apparently endemic to this basin includes Hasemania piatan Zanata & Serra, Parotocinclus jimi Garavello, and at least six new species in process of description.
Hemigrammus brevis Ellis and H. gracilis (Lütken) are small characids species from São Francisco River basin somewhat similar to H. brumado.Beyond the presence of scales covering part of caudal-fin lobes, these two Hemigrammus species also differs from H. brumado in features of coloration and overall external morphology.In life, both Hemigrammus species lack the orange-to reddish body coloration of H. brumado.In alcohol, no dark lateral stripe is visible in Hemmigrammus brevis and a large dark elongated blotch over caudal peduncle is present, usually extending to median caudal-fin rays, and H. brevis has also relatively deeper body (30.5-36.0% vs. 26.8-30.8% in H. brumado).From H. gracilis, the new species differs by having the lateral stripe reaching the end of caudal peduncle and dark pigmentation over median caudal-fin rays (vs.end of caudal peduncle clear, without dark pigmentation over median caudal-fin rays) and smaller eye diameter .Furthermore, males and females of both cited species of Hemigrammus apparently have similar coloration, not showing the sexually dimorphic pattern observed in H. brumado.
Lima & Costa from a small stream in Ilha de Itaparica, H. negodagua Lima & Gerhard from rio Paraguaçu, H. parvellus Ellis from rio Catu and rio Itapicuru, and H. vinaceus Bertaco, Malabarba & Dergam from rio Pardo basin.The remaining northeastern species are somewhat more widespread or occurs just outside the Bahia State, and include H. bifasciatus Ellis from eastern Brazilian rivers, including the south of the Bahia State, H. iheringi Fowler, H. latus Fowler, and H. piabinhas Fowler from Fortaleza, Ceará State, and H. micropterus

Table 1 .
, with mature Morphometric data of holotype and paratypes of Hyphessobrycon brumado (n = 30).The range includes the holotype.SD = Standard deviation.Portion of northeastern Brazil, showing position of type locality of Hyphessobrycon brumado (black dot), rio Brumado, rio de Contas drainage.Brazil, Bahia, Rio de Contas Municipality, rio de Contas drainage, rio Brumado, at Ponte do Coronel.malesbeing predominantly darker in life, usually much darker than females, with a denser concentration of dark chromatophores on the caudal fin forming a diffuse blotch on the caudal peduncle, and a midlateral stripe less evident.According to the authors the coloration of H. negodagua is unique among the species of the genus known until that date, with the possible exception of H. parvellus.Examination of specimens of H. parvellus more recently collected in the rio Pojuca drainage, eastern Bahia State, revealed a color pattern somewhat similar to H. negodagua, mainly by the absence of a humeral spot, absence of a well defined caudal spot, presence of dark chromatophores scattered over body and fins, and dorsal and anal fins with distal portions of first rays white in life.Males and females of H. brumado also have dimorphic coloration, in a pattern similar to that described for the two species above.Males of the species are usually somewhat darker, with concentration of dark chromatophores on the posterior portion of body forming an inconspicuous caudal peduncle blotch, while females possess a rounded caudal blotch and dark pigmentation more restricted to fewer median caudal-fin rays (6-7 vs. 12 rays in males).It is noteworthy that the dimorphic color traits of H. brumado are not conspicuous for the majority of specimens examined and are much less evident than the pattern described for H. negodagua.Notwithstanding, although possessing a series of similarities in color pattern, at least the males of the three species differ in details of this coloration.Mature males of H. parvellus are not as darkened as H. negodagua and possess all fins completely red, with the exception of the caudal fin that has most of its median rays darkened, and tip of dorsal and anal fins white, while the females of both species are more alike, with a more discrete rounded spot over caudal peduncle and fewer median caudal-fin rays darkened.The same pattern occurs on females of H. brumado, while males of the species differs from H. negodagua and H. parvellus by having orange-to reddish coloration of body and fins in life, posterior portion of body not as darkened as H. negodagua and fewer darkened caudal-fin rays than H. parvellus.