Bryconamericus coeruleus, Jerep & Shibatta, 2017

Jerep, Fernando C. & Shibatta, Oscar A., 2017, A new species of Bryconamericus (Characidae: Stevardiinae: Diapomini) from the upper rio Paraná basin, Brazil, Neotropical Ichthyology 15 (3), No. e 170028, pp. 1-13 : 2-9

Bryconamericus coeruleus , new species

urn:lsid:zoobank.org:act:DE5E58DE-35C8-49AA-ADC3-C3D45C836D22

Figs. 1-3

Bryconamericus aff. iheringii . - Portela-Castro et al., 2008:113- 117, figs. 1-4, tab. 1 (cytogenetics; rio Keller, rio Ivaí basin).

Bryconamericus sp. - Frota et al., 2016:3, fig. 2A, tab. 1 (listed in fish inventory of the rio Ivaí basin as an endemic species; voucher: NUP 17150).

Holotype. MZUSP 121505 , 65.4 mm SL (GM), male, Brazil, Paraná State, Marialva, rio Keller, rio Ivaí basin, 23º38’30.0”S 51º51’32.0”W, 10 Feb 2015, G. C. Deprá.

Paratypes. Brazil, Paraná State, upper rio Paraná basin. DZSJRP 21084, 2, 37.7-45.9 mm SL (GM), same data of the holotype. MZUEL 4941 , 1 , 71.3 mm SL, Londrina, District of Guaravera, middle rio Taquara , tributary of rio Tibagi , 23º34’39.7”S 51º09’57.2”W, 11 Oct 2007, R. L. T. Ruiz & W. Galves. MZUEL 4950 , 1 , 68.3 mm SL (GM), Londrina, District of Guaravera , middle rio Taquara , tributary of rio

Tibagi, 23º34’39.7”S 51º09’57.2”W, 11 Oct 2007, R. L. T. Ruiz & W. Galves. MZUEL 14979 , 4 , 57.4-60.4 mm SL (GM), Novo Itacolomi, rio Itacolomi , tributary of rio Ivaí , 23º43’55.6”S 51º32’29.9”W, 25 Mar 2013, A. C. Hoffmann. MZUEL 17097 , 11 , 44.6 -61.0 mm SL (1 c&s, 49.2 mm SL), Londrina , rio Taquara , 23°34’39.7”S 51°09’57.2”W, 23 Nov 2006, W. Galvez and others. NUP 3091, 8, 53.5-66.5 mm SL, Marialva , rio Keller , rio Ivaí basin, ca. 23º30’00.0”S 52º00’00.0”W, 15 Jun 1996, A. L. de B. Portela Castro. NUP 3092, 8, 58.5-68.9 mm SL, Marialva , rio Keller , rio Ivaí basin, ca. 23º30’00.0” S 52º00’00.0” W, 15 Jun 1997, A. L. de B. Portela Castro. NUP 4536, 4, 48.7-60.9 mm SL [2, 49.3-60.9 mm SL (GM)], Nova Tebas , rio Muquilão , tributary of rio Ivaí , 24º24’33.0”S 52º02’39.0”W, 20 Mar 2006, C. H. Zawadzki. NUP 4551, 3, 47.8-62.9 mm SL (2, 50.7-62.9 mm SL), Iretama , rio Formoso , tributary of rio Ivaí , 24º19’04.0”S 52º07’02.0”W, 25 Jul 2006, C. H. Zawadzki. NUP 5923, 1, 61.5 mm SL (GM), Nova Laranjeiras , rio Piquiri , 24º20’19.0”S 52º36’05.0”W, 17 May 2008, W. P. Margarido. NUP 10706, 20, 55.4-68.1 mm SL [7, 55.0- 67.8 mm SL (GM); 3 c&s 54.6-59.9 mm SL], Marialva , rio Keller , rio Ivaí basin, 23º38’30.0”S 51º51’33.0”W, 1 Jan 1900, Nupelia. NUP 11681, 4, 60.6-68.4 mm SL [2, 61.0- 66.3 mm SL (GM)], Marialva , rio Keller , rio Ivaí basin, 23º38’05.0”S 51º50’50.0”W, 10 Jun 2009, E. L. C. Avancini. NUP 15814, 11, 46.5-65.1 mm SL [3, 53.6-61.9 mm SL (GM)], Prudentópolis , rio Barra Grande , rio Ivaí basin, 25º04’55.0”S 51º10’35.0”W, 20 Jan 2014, W. J. da Graça. NUP 16376, 11, 16.4-59.4 mm SL [2, 22.1-59.4 mm SL (GM)], Cândido de Abreu , Lageadão stream, tributary of rio Ubazinho , 24º32’27.0”S 51º20’10.0”W, 5 Apr 2014, G. C. Deprá. NUP 16398, 48, 21.3-54.3 mm SL [5, 22.2-54.3 mm SL (GM)], Cândido de Abreu , rio Maria Flora , tributary of rio Ubazinho , 24º36’33.0”S 51º15’32.0”W, 5 Apr 2014, G. C. Deprá. NUP 17135, 11, 20.5-63.6 mm SL [4, 40.8- 63.6 mm SL (GM), 2 c&s 40.8-46.8 mm SL], Marialva , rio Keller , rio Ivaí basin, 23º38’30.0”S 51º51’32.0”W, 25 Aug 2014, G. C. Deprá. NUP 17150, 18, 25.0- 65.9 mm SL [3, 41.1-65.9 mm SL (GM)], Marialva , rio Keller, rio Ivaí basin, 23º38’30.0”S 51º51’32.0”W, 10 Feb 2015, G. C. Deprá .

Diagnosis. Bryconamericus coeruleus is distinguished from all congeners by the following morphological characters: presence of unaligned teeth in the outer premaxillary tooth row (vs. outer tooth row absent in B. lethostigmus ; outer tooth row series aligned in B. agna Azpelicueta & Almirón, 2001 , B. andresoi Román-Valencia, 2003a , B. arilepis Román-Valencia, Vanegas-Ríos & Ruiz-C., 2008, B. carlosi Román-Valencia, 2003b , B. ecai , B. eigenmanni ( Evermann & Kendall, 1906) , B. guizae Román-Valencia, 2003a , B. huilae Román-Valencia, 2003a , B. hyphesson Eigenmann, 1909 , B. iheringii , B. ikaa , B. lambari Malabarba & Kindel, 1995 , B. leptorhynchus (da Silva & Malabarba, 1996) , B. macrophthalmus Román-Valencia, 2003c , B. maromba ( Malabarba & Malabarba, 1994) , B. ornaticeps Bizerril & Perez-Neto, 1995 , B. patriciae , B. poi ( Almirón, Casciotta, Azpelicueta & Cione, 2001) , B. pyahu Azpelicueta, Casciotta & Almirón, 2003 , B. rubropictus ; B. singularis Román-Valencia, Taphorn & Ruiz-C., 2008, B. subtilisform Román-Valencia, 2003c , B. sylvicola Braga, 1998 , B. tenuis Bizerril & Auraujo, 1992 , B. tolimae Eigenmann, 1913 , B. uporas , B. ytu Almirón, Azpelicueta & Casciotta, 2004 ); a single humeral spot, vertically elongated, expanded and rounded dorsally (vs. two humeral spots in Bryconamericus ecai , B. eigenmanni , and B. ikaa ; a single not dorsally expanded humeral spot in B. andresoi , B. caldasi Román-Valencia , Ruiz-C., Taphorn & García-Alzate, 2014, B. carlosi , B. charalae Román-Valencia, 2005 , B. cismontanus Eigenmann, 1914 , B. diaphanus ( Cope, 1878) , B. foncensis Román-Valencia, Vanegas-Ríos & Ruiz-C., 2009, B. guyanensis Zarske, Le Bail & Géry, 2010 , B. huilae , B. ichoensis Román-Valencia, 2000 , B. iheringii , B. indefessus ( Mirande, Aguilera & Azpelicueta, 2004) , B. lassorum Román-Valencia, 2002 , B. macarenae Román-Valencia, García-Alzate , Ruiz-C. & Taphorn, 2010, B. macrophthalmus , B. mennii Miquelarena, Protogino, Filiberto & López, 2002 , B. motatanensis Schultz, 1944 , B. orinocoense Román-Valencia, 2003c , B. pectinatus Vari & Siebert, 1990 , B. pinnavittatus Dagosta & Netto-Ferreira, 2015 , B. singularis , B. subtilisform , B. tenuis , B. tolimae , B. turiuba , B. yokiae Román-Valencia, 2003d , and B. ytu ; and faint or absent humeral spot in B. alfredae Eigenmann, 1927 , B. bolivianus Pearson, 1924 , B. exodon , B. grosvenori Eigenmann, 1927 , B. multiradiatus Dahl, 1960 , B. novae Eigenmann & Henn, 1914 , B. oroensis Román-Valencia , Ruiz-C., Taphorn & García-A., 2013, B. pachacuti Eigenmann, 1927 , B. patriciae , B. zeteki Hildebrand, 1938 ); 19-22 branched anal-fin rays (vs. 33-38 in B. bucayensis Román-Valencia , Ruiz-C., Taphorn & García-A., 2013, 27- 31 in B. caucanus Eigenmann, 1913 , 18 in B. megalepis Fowler, 1941 , 13- 15 in B. microcephalus , 25-26 in B. osgoodi Eigenmann & Allen, 1942 , 23- 26 in B. phoenicopterus ( Cope, 1872) ; and 5 scale rows between the lateral line and the dorsal-fin origin (vs. 6-8 in B. zamorensis Román-Valencia , Ruiz-C., Taphorn & García-A., 2013).

Description. Morphometric data presented in Tab. 1. Small sized, largest specimen presenting 71.3 mm SL. Body laterally compressed. Body deepest point at dorsal-fin origin. Dorsal profile of head convex from tip of snout to vertical through posterior limit of nostril, slightly concave to straight from that point to tip of supraoccipital spine. Dorsal profile of body convex along predorsal region, straight to slightly convex along dorsal-fin base and from terminus of dorsal-fin base to adipose fin, and straight to slightly concave along caudal peduncle. Ventral profile of head strongly convex from tip of ventral lip to pelvic-fin insertion, slightly convex from that point to anal-fin origin, straight along anal-fin base, and straight to slightly concave along caudal peduncle ( Fig. 1).

(Max) variations include values of the holotype. SD = standard deviation.

Mouth opening subterminal, lower jaw shorter than upper jaw. Premaxillary teeth arranged in two series: inner series with 4*(30) aligned penta- to heptacuspid teeth, decreasing gradually in size laterally; outer series with 4*(22) to 5(8) tri- to pentacuspid teeth. Outer series teeth unaligned. Maxillary teeth 2(10), 3*(14), 4(5), or 5(1), tricuspid, rarely uni- or pentacuspid. 4*(30) large dentary teeth pentacuspid, followed by 2(1), 4(2), 5(2), or 6(1) conical to tricuspid teeth decreasing in size posteriorly ( Fig. 2). Branchiostegal rays 4(6); first gill arch with 1(1) or 2(5) rakers on hypobranchial, 6(3) or 7(3) rakers on ceratobranchial, 1(6) raker on intermediate cartilage, and 5(2) or 6(4) rakers on epibranchial.

Scales cycloid, circulii restricted to anterior portion of scales, with 2-10 divergent radii extending to posterior margin. Longitudinal series with 37(12), 38*(15), or 39(2) pored scales [rarely 35(1)], slightly curved anteriorly. Scales series between longitudinal series and dorsal-fin origin 5*(30). Scales series between longitudinal series and pelvic-fin insertion 3(2), 3.5(15), or 4*(12). Predorsal region with 10(5), 11*(22), or 12(3) scales. Postdorsal region with 10(12), 11*(16), or 12(2) scales. Single scale sheath covering base of anal-fin rays with 7(1), 8(2), 9(10), 10(11), 11(3), or 12*(3). Circumpeduncular scales 13(1) or 14*(29).

Dorsal-fin origin at vertical posterior to pelvicfin insertion. Dorsal-fin rays ii,8*(29) [rarely ii,9(1)]. First unbranched dorsal-fin ray reaching half of length of second unbranched ray. Adipose-fin origin variably at vertical through base of last three branched anal-fin rays. Pectoral fin not reaching pelvic-fin insertion, with i,11(7) or i,12*(22) [rarely i,13(1)] rays. Pelvic fin almost reaching anal-fin origin, with i,7*(30) rays. Anal-fin origin at vertical posterior to end of dorsal-fin base, with iii*(29) or iv(1), 18(1), 19(4), 20*(14), 21(9), or 22(2) rays. Caudal fin i,19,i* (28) [rarely 18(1) or 20(1) rays]. Caudal-fin lobes with similar size, bearing few scales with same body scale size, covering base of rays until first quarter of their length. Dorsal procurrent caudal-fin rays 12(3), 13(2), or 14(1); ventral procurrent caudal-fin rays 10(2), 11(2), or 12(2).

Supraneurals 5(6). Precaudal vertebrae 17(6), caudal vertebrae 18(1), 19(3) or 21(2); total 35(1), 36(3) or 38(2). Coloration in alcohol. Overall body coloration pale yellowish to dusk ( Fig. 1), occasionally with intense deposition of guanine over infraorbitals, opercular, and gular areas of head, longitudinal dark lateral stripe and abdominal region. Head following same overall coloration of body, darker over dorsal surface, upper jaw components, orbital margin of infraorbitals and opercular apparatus, due to higher concentration of dark chromatophores. Midline dorsal scales from posterior tip of supraoccipital to origin of caudal-fin upper lobe darker than lateral of body due to higher concentration of dark chromatophores. Scales from all series above lateral line with proximal region darkened, due to high concentration of dark chromatophores contrasting to clear hyaline distal margin; resulting in diffuse reticulated pattern. Humeral spot single, vertically elongate, extending from two scale series dorsal to lateral line to one scale series ventral to lateral line. Humeral spot darker and wider dorsal to lateral line, two scales-wide and slightly rounded in that region. Dark lateral longitudinal stripe anteriorly diffuse, variably from region between humeral spot and vertical through dorsal-fin origin to end of caudal peduncle; approximately one-scale deep. Humeral spot and dark lateral stripe occasionally omitted by intense deposition of guanine. Fins mostly hyaline with few scattered dark chromatophores on interradial membranes and along margins of rays. Anal fin and middle caudal-fin rays more densely pigmented than remaining fins.

Coloration in life. Overall body dark chromatophores distribution on head, body and fins as described above. Dorsal region of eye with dark chromatophores, occasionally with red tone ( Fig. 3). Overall color of body olive brown to yellow on dorsal region of body; ventral region of body white to light yellow. Lateral of body with silver stripe extending from head to end of caudal peduncle. Body with higher concentration of guanine over infraorbitals, opercular apparatus and ventral region of body. Dorsal and posterior region of body with iridescent blue to greenish tint. Intense orange to red coloration occasionally over proximal region of dorsal and anal fins, also on mid-length of caudal-fin rays. Base of caudal fin lobes yellowish. Distal tip of dorsal and pelvic fins, anterior margin of anal fin, and dorsal, and ventral margins of caudal fin white in some adult specimens ( Fig. 3).

Sexual dimorphism. Secondary sexual dimorphism observed on males with or larger than 40.5 mm SL. Sexually mature males with hooks on pelvic- and analfin rays. Hooks distributed over first unbranched to 11 th branched anal-fin rays; along the posterolateral margin of lepidotrichia in both unbranched and branched regions of rays; one pair of hooks per ray segment. Hooks usually placed over posterior margin of posterior branches, scarcely over posterior margin of anterior branches. All branched pelvic-fin rays bearing one pair of hook per segment, on medial margin of both lateral and medial ray branches. Hooks rarely present on unbranched pelvicfin ray. Sexually mature males bearing gill-gland on the first branchial arch, formed by fusion of five to 11 most anterior gill filaments.

Geographic distribution. The new species is found in tributaries of the rio Tibagi, rio Piquiri and rio Ivaí basins, all from the upper rio Paraná basin ( Fig. 4).

Neotropical Ichthyology, 15(3): e170028, 2017 F. C. Jerep & O. A. Shibatta

Ecological notes. In the rio Taquara basin, Bryconamericus coeruleus was collected in small to medium sized streams, with clear water and bottom composed by rocks and sandy areas. Although found in both slow and rapid waters, the species was more frequently found in pools just after rapids, and also close to the vegetation along the river banks. Syntopic species from rio Taquara are listed in Galves et al. (2007).

Etymology. The specific name, from the Latin coeruleus , is an adjective meaning sky color, in reference to the species bluish iridescence.

Conservation status. Following to the IUCN criteria (IUCN, 2016) and up to date information about Bryconamericus coeruleus , the species can be categorized as Least Concern (LC). The known extent of occurrence is restricted to less than 20,000 km 2 (Extent of Occurrence - EOO of approximately 16,592 km 2) in a region with continuing decline of habitat quality due to riparian forest degradation. Furthermore, the species is known to exist at no more than nine locations (rio Barra Grande, rio Formoso, rio Itacolomi, rio Keller, rio Maria Flora, rio Muquilão, rio Piquiri, rio Taquara and rio Ubazinho). However, additional studies on population dynamics might bring more detailed information about the conservation status of the species.

Sympatric species and multivariate morphometric analysis. Bryconamericus coeruleus is sympatric to four species of Stervadiinae in its area of occurrence: B. iheringii , B. turiuba , Piabina argentea , and Piabarchus stramineus . The geometric morphometrics analysis by mean of CVA evidenced four morphological distinct groups on first (39.1%) and second (30.3%) canonical variates axis ( Fig. 5). Bryconamericus coeruleus formed a group with B. iheringii from Laguna dos Patos basin and from upper rio Paraná. A second grouping was formed by B. exodon and Piabachus stramineus . Piabina argentea from rio São Francisco basin were distinguished from all other species including the P. argentea from upper rio Paraná basin, which formed another group with B. turiuba , evidencing morphological similarities. These unnatural groupings evidenced convergence of body form among different taxa. In a separate analysis, when comparing Bryconamericus coeruleus with B. iheringii , the species with most similar body shape among the sympatric species of Stevardiinae , the PCA showed distinction of Bryconamericus coeruleus on first axis ( Fig. 6).The first axis retained 33.4% of data variation, while the second axis retained 17.7%.

The consensus landmarks of geometric morphometrics evidenced the highest body depth to Bryconamericus coeruleus and B. iheringii , and the smallest body depth to Piabina argentea , that also presented the longest head and longest snout ( Fig. 7). The origin of dorsal fin of Bryconamericus coeruleus is positioned similarly to B. iheringii from upper rio Paraná basin, but the posterior insertion is similar to B. iheringii from Laguna dos Patos basin, consequently the new species present a smaller dorsal-fin base length. The location of the pelvic-fin origin in Bryconamericus coeruleus is anterior when compared to specimens from both populations of B. iheringii . The same is observed in the origin of the anal fin, which is anterior to the vertical line at the end of dorsal-fin base compared to both populations of B. iheringii (at same line in B. iheringii from upper rio Paraná and posterior in B. iheringii from Laguna dos Patos). The body depth is mostly evidenced by the distance from the origin of dorsal fin to the pelvic-fin insertion, and the end of dorsal-fin base to the origin of anal fin. The anal-fin base length in Bryconamericus coeruleus is one of the longest among the analyzed species, except to Piabarchus stramineus .