A new species of Hemibrycon ( Teleostei : Characiformes : Characidae ) from the Roble River , Alto Cauca , Colombia , with a key to species known from the Magdalena – Cauca River Basin

The character traditionally used to defi ne Hemibrycon is: maxilla with teeth along the greater part of its length (Günther, 1864; Eigenmann, 1927) but that trait is considered to be homoplasic and variable among species of Hemibrycon (Arcila-Mesa, 2008). Other genera that have teeth along most of the maxillary border are Henochilus and Hollandicthys (Eigenmann, 1927; Castro et al., 2004). Eigenmann (1927) recorded between three and eleven teeth in species of Hemibrycon; Géry (1962) stating that the number varied depends on A new species of Hemibrycon (Teleostei: Characiformes: Characidae) from the Roble River, Alto Cauca, Colombia, with a key to species known from the Magdalena – Cauca River Basin


Introduction
The character traditionally used to defi ne Hemibrycon is: maxilla with teeth along the greater part of its length (Günther, 1864;Eigenmann, 1927) but that trait is considered to be homoplasic and variable among species of Hemibrycon (Arcila-Mesa, 2008).Other genera that have teeth along most of the maxillary border are Henochilus and Hollandicthys (Eigenmann, 1927;Castro et al., 2004).Eigenmann (1927) recorded between three and eleven teeth in species of Hemibrycon; Géry (1962) stating that the number varied depends on the age from fi ve to fi fteen.Even so, Hemibrycon has traditionally been distinguished from Bryconamericus by only this character (Román-Valencia, 2001) and recently this character was also used by Malabarba & Weitzman (2003) to distinguish Hemibrycon from Cyanocharax.Arcila-Mesa (2008) found Bryconamericus to be the sister genus to Hemibrycon based on three synapomorphies: modifi cations of the jaws and suspensorium and the shape of the scales of the caudal fi n.The genus Hemibrycon Günther has been shown to be monophyletic based on four synapomorphies: presence of ectopterygoids with widened ventral anterior projection, four to six times wider than posterior part; a red spot present in life on ventral margin of caudal peduncle; a postero-ventral projection on the pterotic and fi rst infraorbitals gradually decreasing in width from posterior tip and located near posterior part of antorbital (Arcila-Mesa, 2008); its taxonomy is fairly well known (Román-Valencia et al., 2006;2007;2009a;b;c;2010a;b;Román-Valencia & Ruiz-C., 2007;Bertaco et al., 2007;Román-Valencia & Arcila-Mesa, 2008;2009;2010;Zarske, 2008).H. dentatus from upper Cauca River and H. decurrens from the lower Magdalena River have been shown to be synonyms of B. caucanus (Román-Valencia et al., 2009a).
The purpose of this paper is to describe a new species of Hemibrycon from Alto Cauca, Colombia, as a further contribution from the fi rst author's ongoing revision of Hemibrycon species in South America, and is proof of the as yet undocumented biodiversity of the genus.

Materials and Methods
Measurements were taken with digital calipers, recorded to 0.1 mm precision and usually expressed as percentages of standard or head length (Table 1).Counts were made using a stereoscope with a dissection needle to extend the fi ns.Counts and measurements were taken from the left side of specimens when possible and in general were taken according to guidelines in Vari & Siebert (1990).
In the list of paratypes, the number of individuals is given immediately after the catalog number, which is followed by the range of Standard Length in mm for that lot; for example : IUQ 2300, 6, 46.36 -65.43We do not translate locality information because key information from original labels is often lost by inaccurate translation.
The 21 morphometric characters analyzed in this study (Table 1) were evaluated by Principal Component Analysis (PCA) using the Burnaby method to eliminate the infl uence of size with the PAST program, version 1.81 for Windows (Hammer et al., 2008).

Hemibrycon palomae new species
Description.Body slender and elongate (mean maximum body depth about 27.1 % SL).Area above orbits convex.Dorsal profi le of head and body oblique from the supraoccipital to dorsal origin and from the last dorsal-fi n ray to the base of the caudal fi n.Ventral profi le of body convex from snout to base of anal-fi n.Caudal peduncle laterally compressed.Head and snout short, mandibles equal, mouth terminal, lips soft and fl exible, and not covering the outer row of premaxilla teeth; ventral border of the upper jaw straight; posterior edge of the maxilla reaching anterior edge of orbit.
Premaxilla with teeth in two rows.Four to six teeth of outer row tricuspid with central cusp larger.Internal row with four tricuspid teeth.Maxilla long, posterior margin straight, with eigth to ten teeth, each with one to three cusps.Dentary with three large tricuspid teeth with the central cusp largest, followed by eleven or twelve smaller teeth with one to three cusps.
Anal-fi n rays iii -v, 24 -27 (iv, 26*; n = 34).Anal-fi n origin posterior to vertical through base of fi rst dorsalfi n ray.Pectoral-fi n rays ii, 10 (n = 34).Pelvic-fi n rays ii, 6 (ii, 6*, n = 34).Pelvic-fi n origin anterior to vertical through dorsal-fi n origin.Caudal fi n not covered with scales, forked with short pointed lobes, principal caudal rays 1/17/1 (n = 34).Dorsal procurrents rays 12 (n = 34).Ventral procurrents rays 12 (n = 34).Adipose fi n present.Total number of vertebra 40 -41.Five infraorbitals present, the fi rst thin and narrow, extending between the dorsal edge of maxila and lateral ethmoid, with sensorial canal.Second infraorbital short and wide, covering the dorsal part of the angulo-articular, anterior part of second infraorbital overlaying anterior part of fi rst infraorbital and with a foramen that extends towards the dorsal margin of the fi rst infraorbital; its posterior margin extends below the third infraorbital.Third infraorbital the widest and longest, its ventral border in contact with the sensorial canal of preopercle.Fourth and fi fth infraorbitals short and narrow, covering the posterior margin of the hyomandibular.Supraorbital absent.Seven supraneurals present between the head and the anterior part of the dorsal fi n, without cartilage on the upper and lower edges, and with medial sensorial canal.simple anal-fi n ray, each ray has 3 -11 hooks, located on the posterior-most branch.There are also 12 -14 small hooks on the branched rays of the pelvic fi n, located on both branches of the rays, extending onto the anterior-most part, also in the pectoral fi n with 2 to 4 hooks on the distal end of the spokes.There are 4 -10 hooks on the distal end of dorsal fi n.

Secondary sexual dimorphism. Males have a row of very short hooks, on all branched and one
Life colors.Dorsum dark blue, sides of body silveryyellow, ventrum silvery-white.Humeral spot dark and rounded.Purple opercular spot visible only in live fi sh.Dark stripe on caudal peduncle extends onto middle caudal-fi n rays.Posterior portion of caudal peduncle with reddish blotch; dorsal margin of caudal peduncle with two reddish spots.Dark horizontal stripe on central caudal-fi n rays bordered above and below by yellow stripes.Pectoral, pelvic and anal fi ns yellowish, dorsal fi n dark red.
Distribution.This species is so far known from the Paloma and La Siria Creek, Roble River drainage in Quindío state, Alto Cauca, Magdalena River system in Colombia.
Habitat.palomae sp.n. was collected along shore over sandy substrates in the mainstream of La Paloma Creek.The pH is around neutral (7.7), oxygen concentration was low from 4.8 -5.3 mg/l, as was the percent oxygen saturation (60 -65.9 %), temperature air 22. 5 -23.5

Discussion
Principal component analysis of all species produced no signifi cant results, however, it did indicate that H. palomae can be distinguished from de H. colombianus, from Magdalena river, by eye diameter vs. maxilla length in the fi rst component, by the length of the caudal peduncle vs. snout length in the second component and by caudal peduncle depth vs. postorbital head length in the third component.The fi rst component explained 32.41 % of the total variation, while the second component of the 18.17 % of the variation between the fi rst and third component explains 60.56 %.
The genus Hemibrycon was found to be monophyletic based on osteological and other characters (Arcila-Mesa, 2008).Hemibrycon palomae sp.n. has all of the synapomorphies observed in other Hemibrycon.
A common requirement for the description of a new species is to compare the new taxon with all other known species in the genus.However, we do not share that idea, not because technically it has no truth, but when dealing with large genera such as Bryconamericus, Creagrutus, Hyphessobrycon, Hemigrammus, Astyanax or Hemibrycon, it is not feasible, nor in our opinion, necessary.In the modern sense of our thinking, we would not expect there to be any species in common between the Magadalena/Cauca Basin of northern Colombia and the drainages of southern Brazil or Argentina.Instead, we provide a practical key to the species present locally, as has been done for other genera of Characidae (Vari & Harold, 2001;(Román-Valencia et al., 2008a;b;2009b;c;2010b;Román-Valencia & Arcila-Mesa, 2008).
Etymology.Hemibrycon palomae sp.n. is named after the La Paloma Creek, Rio Roble, La Vieja River Basin, Alto Cauca, Colombia, where the type series was collected.

Fig. 2 .
Fig. 2. Representation of the fi rst two principal components (component 1 is the X axis, component 2 is the Y axis) from morphometric data of Hemibrycon palomae sp.n. (+) and H. colombianus ( ■ ).
Tab. 1. Morphometric of Hemibrycon palomae sp.n. standard and total length in mm, mean in parentheses.