Characidium tapuia, Zanata & Ramos & Oliveira-Silva, 2018

Zanata, Angela M., Ramos, Telton P. A. & Oliveira-Silva, Leonardo, 2018, A new species of Characidium (Characiformes: Crenuchidae) from the rio Parnaíba basin, northeastern Brazil, Zootaxa 4514 (1), pp. 77-86 : 78-84

publication ID	https://doi.org/ 10.11646/zootaxa.4514.1.6
publication LSID	lsid:zoobank.org:pub:2BE61D04-7FC3-4B14-B2DE-A7E0091DFEB7
DOI	https://doi.org/10.5281/zenodo.5986088
persistent identifier	https://treatment.plazi.org/id/8A7D433D-6445-F148-FF42-FBCFFC6B1FA1
treatment provided by	Plazi
scientific name	Characidium tapuia
status	sp. nov.

Treatment

Characidium tapuia , new species

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Characidium sp. 1: Ramos et al., 2014: 4 (Rio Parnaíba basin, listed).

Characidium sp. 1: Silva et al., 2015: 4 (Rio Gurgueia, listed).

Holotype. UFPB 11604 View Materials , 32.1 View Materials mm SL, Brazil, Maranhão, Loreto, creek tributary of rio Balsas , at the road between Loreto and Buritirana, Fazenda Fogoso, 06°59'34”S, 45°11'07”W, 275 m a.s.l., 0 9 Feb 2009, T. Ramos, R. Ramos, G. Moro & P. Chavert. GoogleMaps

Paratypes. All from Brazil, rio Parnaíba basin. Maranhão State . UFPB 9423 View Materials , 9 View Materials , 24.1 View Materials – 32.1 View Materials mm SL, 2 c&s, 31.0–34.0 mm SL ; UFBA 8511 , 3 , 29.8 – 32.1 mm SL, 1 c&s, 30.8 mm SL, collected with holotype GoogleMaps . UFPB 11313 View Materials , 1 View Materials , 24.1 View Materials mm SL, São Raimundo das Mangabeiras, rio Balsas sub-basin, Riacho Cachoeira , 07°02'00”S 45°27'52”W, 0 8 Feb 2009, T. Ramos, R. Ramos, G. Moro & P. Chavert GoogleMaps . UFPB 11328 View Materials , 1 View Materials , 27.2 View Materials mm SL, São Raimundo das Mangabeiras, rio Balsas sub-basin, Ribeirão Riachão , 07°08'44”S 45°42'18”W, 0 6 Apr 2005, W. Severi & E. França GoogleMaps . MZUSP 87479 View Materials , 1 View Materials , 32.9 View Materials mm SL, Balsas, rio Balsas sub-basin, Ribeirão Jenipapo , 07°26'18”S 46°11'47”W, 23 Mar 2005, A. Akama & E. Baena. Piauí State GoogleMaps . UFPB 11326 View Materials , 3 View Materials , 27.2 View Materials – 32.4 View Materials mm SL, Palmeira do Piauí, rio Gurgueia sub-basin, stream Brejo Novo , 08°43'43”S 44°13'52”W, 0 3 Apr 2010, B. Silva GoogleMaps . UFPB 11327 View Materials , 1 View Materials , 30.9 View Materials mm SL, Urucuí, rio Gurgueia sub-basin, Riacho da Volta , 07°24'16”S 44°50'31”W, 31 Mar 2005, W. Severi GoogleMaps . UFPB 11329 View Materials , 1 View Materials , 27.5 View Materials mm SL, Palmeiras, Gurgueia sub-basin, Riacho do Negro , 05°46'12”S 043°04'23”W, 0 9 Apr 2005, W. Severi GoogleMaps . UFRN 2784 , 1 , 27.3 mm SL, Corrente, rio Gurgueia sub-basin, rio Corrente , 10°21'9”S 45°7'38”W, 18 Jun 2014, S. Lima, R. Paiva, M. Silva & Y. Ponce GoogleMaps . UFRN 2871 , 6 , 19.3 –30.0 mm SL, São Gonçalo do Gurgueia, rio Gurgueia, Parque das Araras , 10°06'27”S 45°21'24”W, 19 Jun 2014, T. Ramos, L. Neto, M. Germano & L. Medeiros GoogleMaps . UFRN 3175 , 1 , 22.3 mm SL, Alto Parnaíba, small tributary of rio Riozinho , 09°51'18”S 46°16'32”W, 23 Jun 2014, T. Ramos, S. Lima, M. Silva, R. Paiva & Y. Rocha GoogleMaps . MZUSP 98568 View Materials , 6 View Materials , 19.2 View Materials – 25.5 View Materials mm SL, Santa Filomena, Riacho Recreio, tributary of rio Parnaíba , 09°9'52”S 45°51'14”W, 0 7 Apr 2001, O. Oyakawa, A. Akama, V. Garutti & C. Nolasco GoogleMaps .

Diagnosis. Characidium tapuia can be distinguished from its congeners, except C. lanei Travassos , C. nana Mendonça & Netto-Ferreira , and C. samurai Zanata & Camelier , by the presence of a broad (at least one scale wide) and conspicuous dark lateral stripe extending from tip of snout to end of caudal peduncle, and by the absence of dark vertical bars on body on specimens larger than 23.0 mm SL ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 ). The new species is distinguished from C. lanei by having four, rarely three, horizontal scale rows above the lateral line (vs. five), 12 circumpeduncular series of scales (vs. 13 or 14), parietal branch of the supraorbital canal present (vs. parietal branch absent), a clearly visible basicaudal dark spot located somewhat posterior to the end of the longitudinal dark stripe (vs. absence of a clearly visible basicaudal dark spot), ventral portion of head and portion of body ventral to the dark longitudinal stripe poorly or not pigmented (vs. ventral and dorsal portions of head and body similarly pigmented), presence of a very small dark spot immediately anterior to the insertion of the first dorsal-fin ray ( Fig. 2a View FIGURE 2 ; vs. absence), and absence of dark bars on the anal fin (vs. presence). Characidium tapuia differs from C. nana by having a complete lateral line (vs. incomplete), presence of adipose fin (vs. absence), and presence of the parietal branch of the supraorbital laterosensory canal (vs. absence). From C. samurai , the new species differs by having 12 circumpeduncular scales rows (vs. 14) and midlateral stripe with somewhat irregular borders due to blotches slightly extending dorsally or ventrally (vs. lateral band with straight borders overall).

Description. Morphometric data of holotype and paratypes in Table 1. Body elongate and moderately compressed. Greatest body depth at vertical through dorsal-fin origin. Dorsal profile convex from upper lip to end of occipital process, slightly convex or straight from this point to origin of dorsal-fin base, convex along dorsal-fin base, almost straight between end of dorsal-fin base to origin of anteriormost dorsal procurrent caudal-fin ray.Ventral profile of head straight, except for slightly convex portion close to dentary symphysis, slightly convex from isthmus to pelvic-fin origin, straight from latter point to anal-fin origin, straight from this point to origin of anteriormost ventral procurrent caudal-fin ray. Snout triangular in lateral view, rounded dorsally. Mouth subterminal, aligned or slightly lower than ventral edge of the orbit. Distal tip of maxilla not reaching vertical through anterior margin of orbit. Orbit approximately round, larger than snout length. Cheek thin, its depth approximately a quarter to a seventh of orbit diameter. Nares separated and without distinctly raised margins; posterior naris considerably closer to orbit than to anterior naris. Supraorbital well developed. Nasal bones with narrow lateral lamella or with ossified canal devoid of lamellae. Parietal fontanel limited anteriorly by frontals. Parietal branch of supraorbital canal present.

Dentary teeth in two rows; outer series with 8 (1) or 11 (2) teeth, uni-, bi- or tricuspid; teeth decreasing in size from symphysis; inner series with several minute conical teeth inserted on edge of replacement tooth trench. Premaxilla with single series of 6 (1), 8 (1) or 9 (1) uni- or bicuspid teeth, decreasing in size from symphysis. Maxillary edentulous. Ectopterygoid with about 8 (1), 11 (1) or 15 (1) teeth arranged in one (2) or two (1) series. Mesopterygoid teeth absent.

Scales cycloid; circulii absent and 5–10 divergent radii present on exposed portion of scales. Lateral line completely pored, with 32 (2), 33* (20) or 34 (3) pored scales; horizontal scale rows above lateral line 3.5 (7) or 4* (18); horizontal scale rows below lateral line 3 (26). Scales along middorsal line between supraoccipital and origin of dorsal fin 8 (7) or 9* (18). Scale rows around caudal peduncle 12 (26). Isthmus with anteriormost small portion covered with scales. Pseudotympanum present as a muscular hiatus at vertical through anterior portion of swimbladder and mainly situated between ribs of the fifth and sixth vertebrae, with large opening anterior to the sixth vertebrae ( Fig. 3 View FIGURE 3 ).

Dorsal-fin rays iii,9* (25) or ii,10 (1); distal margin of dorsal nearly straight. Adipose fin well developed. Pectoral-fin rays 11–12 total rays; unbranched anterior rays ii (3), iii* (24) or iv (1), and posterior total rays 7 (2), 8 (11), 9* (10) or 10 (4); 2 (1), 3 (1) and 4 (1) unbranched posterior rays; first and second branched pectoral-fin rays usually longest. Posterior tip of pectoral fin reaching pelvic-fin insertion in specimens up to 30.0 mm SL; larger specimens with tip of pectoral fin falling short of pelvic-fin insertion. Pelvic-fin rays highly variable, i,5,iii (2), i,6,i(6), i,6,i (4),i,7,i* (12) or i,8 (3); second and third branched pelvic-fin rays longest; posterior tip of pelvic fin falling short anal-fin ray origin. Anal-fin rays ii,6* (11) or iii,7 (16); posterior margin of anal fin somewhat pointed posteriorly, with first and second branched usually longest; fin elements (i.e., adnate rays) on last pterygiophore 2 (26). Caudal-fin rays i,9,8,i (21). Dorsal procurrent caudal-fin rays 7 (1) or 8 (2); ventral procurrent caudal-fin rays 6 (3).

Total number of vertebrae 33 (3); precaudal vertebrae 16(1) or 17(2); caudal vertebrae 17 (3). Supraneural bones 4 (1) or 5 (2). Epural bones 2 (3). Uroneural bone 1 (3). Branchiostegal rays 5 (3), 4 connected to anterior ceratohyal, 1 connected to the posterior ceratohyal.

Color in alcohol. Ground color of head and body pale brown ( Fig. 1a View FIGURE 1 , 2 View FIGURE 2 ). Dark conspicuous stripe extending from snout to posterior margin of opercle. Dark and somewhat broad (at least one scale wide) midlateral stripe from the rear of opercle to the end of caudal peduncle. Dark humeral blotch absent. Basicaudal black spot well defined, located slightly posterior to the end of longitudinal stripe, not continuous to it. Two or three dorsalmost longitudinal series of scales darkened by light brown chromatophores, resulting in a somewhat homogeneously brown dorsal area. Specimens smaller than 23.0 mm SL with up to nine inconspicuous dark vertical bars on body; bars not visible on larger specimens. Specimens without dark vertical bars with variable presence of short dark and pointed vertical projections on borders of the midlateral stripe; projections may represent remnants of the vertical bars observed in juveniles. Specimens larger than 22.0 mm SL with a distinct small dark dot immediately ahead of the insertion of the first dorsal-fin ray; small specimens with dot poorly visible or absent. Ventral half of head and body mostly clear, devoid of dark pigmentation, except by sparse melanophores on dorsal border of opercle and borders of some scales adjacent to the longitudinal dark stripe. Fins mostly hyaline. Dorsal fin with inconspicuous dark band below midlength of rays, formed by relatively large melanophores. Remaining fins without dark bars or blotches; borders of rays slightly dark, more evident on caudal-fin rays.

Color in life. Ground color clear, slightly olivaceous dorsally ( Fig. 1b View FIGURE 1 ). Iris, infraorbital, opercle and anteriormost ventral portion of body silvery. Fins mostly hyaline, with sparse melanophores on borders of rays.

Etymology. Named after the Tapuia Indians that originally inhabited the area where the species occurs. The word tapuia means barbarous, enemy in Tupi language. In fact, the term tapuia was used to designate a series of different non-tupi ethnic groups, originally inhabiting a broad area from Bahia to Ceará States. The rio Parnaíba itself was originally known as Rio Grande dos Tapuias ( Sobrinho, 1946). A noun in apposition.

Sexual dimorphism. No hooks on fins or other sexually dimorphic features were observed externally on specimens examined.

Distribution. Characidium tapuia is only known to the upper and middle portions of the rio Parnaíba basin, Maranhão and Piauí states, Brazil ( Fig. 4 View FIGURE 4 ).

Habitat and ecological notes. Characidium tapuia was sampled both in the main channel of the rio Parnaíba and its tributaries Gurgueia and Balsas. These are the largest tributaries on the right and left margins of the rio Parnaíba, respectively. The new species is apparently restrict to perennial rivers, situated about 500 m above sea level, with transparent water, moderate current flow, rocky and sandy substrate, and little aquatic vegetation ( Fig. 5 View FIGURE 5 ). The riparian vegetation is typical of flooded areas of the Cerrado, with palms of the species Mauritia flexuosa . The collecting sites are well preserved, without noticeable anthropic alteration. In the rio Gurgueia, C. tapuia was collected syntopically with Bryconops cf. melanurus (Bloch), Cetopsorhamdia sp., Knodus victoriae (Steindachner) , Moenkhausia sanctaefilomenae (Steindachner) , and Parotocinclus cabessadecuia Ramos , Lima & Ramos. In the rio Balsas, the new species co-occurs with Aspidoras raimundi (Steindachner) , Astyanax fasciatus (Cuvier) , A. lacustris (Lütken) , Cichlasoma sanctifranciscense Kullander , Compsura heterura Eigenmann , Crenicichla menezesi Ploeg , Hemigrammus rodwayi Durbin , Hypostomus johnii Steindachner , Hoplerythrinus unitaeniatus (Spix & Agassiz) , Jupiaba polylepis (Günther) , Loricaria parnahybae Steindachner , Myloplus asterias (Müller &Troschel) , Phenacogaster calverti (Fowler) , Poecilia vivipara Bloch & Schneider , Serrapinnus heterodon (Eigenmann) and S. piaba (Lütken) . In the rio Corrente, a tributary of the high portion of the rio Gurgueia basin, C. tapuia was recorded in co-occurrence with C. aff. zebra Eigenmann , Corydoras vittatus Nijssen , Hemigrammus marginatus Ellis , Hoplias malabaricus (Bloch) , Moenkhausia sp., Poptella compressa (Günther) , Pimelodella parnahybae Fowler , Prochilodus lacustris Steindachner and Steindachnerina notonota (Miranda Ribeiro).

Conservation. Characidium tapuia apparently does not match any of the extinction risk categories according to the International Union for Conservation of Nature (IUCN). The species possesses a relatively broad distribution, occurring at the upper and middle portions of the rio Parnaíba basin, including well preserved areas close to the Parque Nacional das Nascentes do Rio Parnaíba, a national park. Therefore, according with the currently available data, and using the criteria of the IUCN Standards and Petitions Subcommittee (IUCN, 2017), C. tapuia should be classified as Least Concern (LC).

Remarks. Characidium tapuia apparently does not fit in any group of Characidium previously proposed in the literature ( Buckup & Reis, 1997; Buckup & Hahn, 2000; Graça & Pavanelli, 2008; Netto-Ferreira et al. 2013; Mendonça & Netto-Ferreira, 2015). Although the species externally resembles C. lanei and C. nana , both members of clade C4 of Buckup (1993b), particularly by sharing a broad conspicuous dark longitudinal band, C. tapuia does not share any of the synapomorphies of the C4 clade of Buckup & Reis (1997) and Buckup & Hahn (2000), i.e., absence of the parietal branch of the supraorbital canal, increased number of vertical bars on the sides of the body and absence of the inner row of dentary teeth.

The new species is apparently a dweller of slow- to moderate-flowing aquatic environments and does not possess the adaptations cited by Buckup et al. (2000) present in congeners that inhabit fast-flowing water environments, as a robust body and paired-fins modifications. Rather, somewhat fragile paired fins are observed in the new species and congeners that inhabit more lentic environments (e. g., C. bahiense , C. bimaculatum , and C. helmeri ). The pectoral- and pelvic fins of C. tapuia are not distinctly enlarged and the rays are similar overall, with no thicker or shorter ray segments. Characidium tapuia possesses a well-developed pseudotympanum, with most of the hiatus situated between ribs of the fifth and sixth vertebrae, but with somewhat large opening anterior to rib of fifth and small opening posterior to rib of sixth vertebra ( Fig. 3 View FIGURE 3 ). Thus, part of the first and second ribs are exposed and completely embedded within the aperture. The overall structure of the pseudotympanum of C. tapuia is similar to that described to C. bahiense ( Zanata & Camelier, 2014) , C. mirim and C. xavante ( Zanata & Ohara, 2015) . As pointed by Zanata & Ohara (2015), a large and widely exposed pseudotympanum is commom to species of Characidium that inhabit relatively slow-flowing waters (e.g., C. bahiense , C. mirim , C. nupelia , C. xavante , and C. stigmosum ), a correlation also exemplified by C. tapuia . However, C. tapuia possesses a completely pored lateral line, distinctly from the congeners with a wide pseudotympanum cited above, which present an incompletely pored lateral line.

Comparative material examined. All listed specimens are alcohol-preserved (except when noted). All from Brazil, except if otherwise noted: Characidium alipioi : MNRJ 5550 View Materials , (holotype, 50.0 mm SL), Rio de Janeiro, rio Paraíba do Sul basin ; MZUSP 80224 View Materials , (12, 36.5–61.9 mm SL), Rio de Janeiro, rio São João basin ; MZUSP 112331 View Materials (6, 50.3–72.3 mm SL), São Paulo, rio Paraíba do Sul basin. Characidium bahiense : MZUSP 8940 View Materials (holotype, 16.0 mm SL), Bahia, Arembepe ; UFBA 2886 (4, 19.1–22.0 mm SL), Bahia, rio Inhambupe basin ; UFBA 4348 (18, 18.0– 24.1 mm SL), Bahia, rio Paraguaçu basin ; UFBA 4685 (20, 17.2–22.2 mm SL), Bahia, rio Capivara basin ; UFBA 7167 (23, 3 c&s, 21.1–26.0 mm SL), Bahia, rio Itapicuru basin. Characidium bimaculatum : MNRJ 4925 View Materials (1, 25.5 mm SL) ; MNRJ 4928 View Materials (1, 28.7 mm SL), Ceará, rio Salgado basin ; MNRJ 4975 View Materials (1, 29.4 mm SL), Ceará, rio Cotuí ; MNRJ 21249 View Materials (14, 20.5–41.4 mm SL), Ceará, rio Curu basin ; MZUSP 1107779 View Materials (8, 29.4– 24.3 mm SL), Paraíba, rio Acaraú basin ; UFBA 3829 (6, 1 c&s, 22.5–30.8 mm SL), Paraíba, rio Piranhas basin. Characidium fasciatum : MZUSP 39676 View Materials (15, 32.7–36.4 mm SL), Minas Gerais, rio São Francisco basin. Characidium gomesi : MZUSP 73193 View Materials (47, 25.8–32.0 mm SL), Minas Gerais, rio Paranaíba basin . MZUSP 88440 View Materials (3, 29.5–42.8 mm SL), São Paulo, rio Corumbataí. Characidium grajahuensis : MNRJ 3855 View Materials (holotype: snout damaged, precise measurement currently not possible), Rio de Janeiro, Grajaú. Characidium hasemani : MZUSP 91785 View Materials (4, 44.0–58.0 mm SL), Mato Grosso, rio Xingu basin. Characidium heirmostigmata : MZUSP 97738 View Materials (holotype, 34.6 mm SL), Paraná, rio Paraná basin. Characidium interruptum : MZUSP 58992 View Materials (1, 30.9 mm SL), Rio de Janeiro, rio São João basin. Characidium japuhybense : MNRJ 5194 View Materials (holotype: snout damaged, precise measurement currently not possible), Rio de Janeiro, Angra dos Reis. Characidium lagosantense : MNRJ 3852 View Materials (holotype: snout damaged, precise measurement currently not possible), Minas Gerais, rio São Francisco basin ; MNRJ 18108 View Materials (71, 11.2–31.2 mm SL), Minas Gerais, rio São Francisco basin. Characidium lanei : MNRJ 6185 View Materials (holotype, 40.8 mm SL), São Paulo, rio Ribeira do Iguape basin ; MNRJ 32884 View Materials (38, 20.9–36.4 mm SL), São Paulo, rio Lajeado ; MZUSP 69585 View Materials (7, 25.2–31.0 mm SL), São Paulo, rio Ribeira do Iguape basin. Characidium laterale : MZUSP 90204 View Materials (2, 20.6–25.1 mm SL), Mato Grosso, rio Paraguai basin ; MZUSP 96687 View Materials (80, 15.7–24.0 mm SL), Mato Grosso, rio Paraguai basin. Characidium lauroi : MNRJ 5529 View Materials (holotype, 60.4 mm SL), Rio de Janeiro, rio Paraíba do Sul basin ; MZUSP 110359 View Materials (5, 31.1–45.9 mm SL), São Paulo, rio Paraíba do Sul basin. Characidium nana : MZUSP 117154 View Materials (paratypes, 3, 16.7–21.3 mm SL), Pará, rio Xingu basin. Characidium nupelia : MZUSP 87743 View Materials (holotype, 29.0 mm SL), Mato Grosso, rio Paraguai basin. Characidium oiticicai : MNRJ 9480 View Materials (holotype, 35.3 mm SL), São Paulo, rio Tietê basin ; MZUSP 108640 View Materials (2, 37.4–38.1 mm SL), São Paulo, rio Tietê basin. Characidium pterostictum : MZUSP 43547 View Materials (15, 28.7–37.8 mm SL), Rio Grande do Sul , Mampituba system. Characidium rachovii : MZUSP 49163 View Materials (8, 25.9–34.2 mm SL), Rio Grande do Sul , Lagoa dos Patos drainage. Characidium samurai : MZUSP 108188 View Materials (holotype, 46.6 mm SL), Bahia, rio das Almas basin ; MZUSP 112385 View Materials (paratypes, 9, 1 mol, 25.4–42.7 mm SL) ; UFBA 7259 (paratypes, 7, 20.8–42.6 mm SL), collected with holotype. Characidium stigmosum : MZUSP 40804 View Materials (holotype, 33.5 mm SL), Goiás, rio Tocantins basin. Characidium tenue : MZUSP 63803 View Materials (6, 31.0– 42.2 mm SL), Rio Grande do Sul, rio Jacuí basin. Characidium timbuiense : MNRJ 4285 View Materials (holotype, 51.8 mm SL) ; MNRJ 4284 View Materials (paratype, 56.9 mm SL) ; MNRJ 4292 View Materials (paratype, 53.1 mm SL) ; MNRJ 4315 View Materials (paratype, 48.8 mm SL) ; UFBA 6506 (6, 1 c&s, 27.9–44.0 mm SL), Espírito Santo, rio Timbuí basin. Characidium vidali : MNRJ 9757 View Materials (holotype, 47.8 mm SL), Rio de Janeiro, rio Soberbo. Characidium xavante : MZUSP 87745 View Materials (paratypes, 20, 13.9–22.7 mm SL), Mato Grosso, rio Xingu basin. Characidium cf. zebra : MZUSP 92910 View Materials (7, 26.5– 29.0 mm SL), Amazonas, rio Negro basin . MZUSP 77838 View Materials (2, 23.5–27.1 mm SL), Peru, Loreto, rio Pastaza basin . MZUSP 96477 View Materials (1, 35.0 mm SL), Venezuela, Bolivar, Rio Orinoco basin .