Characidium kalunga, Melo & Bouquerel & Masumoto & França & Netto-Ferreira, 2021

Melo, Marcelo R. S., Bouquerel, Bárbara B., Masumoto, Flávia T., França, Rayane S. & Netto-Ferreira, André L., 2021, A new species of Characidium (Characiformes: Crenuchidae) from the Chapada dos Veadeiros, Goiás, Brazil, Neotropical Ichthyology (Neotrop. Ichthyol.) 19 (2), pp. 1-20 : 3-12

Characidium kalunga , new species

urn:lsid:zoobank.org:act:1B75F475-E28A-4BD9-8571-E6FD51296B18

( Figs. 1–7 , Tab. 1 )

Holotype. MZUSP 125824 , 40.5 mm SL, male, Brazil, Goiás, Alto Paraíso de Goiás, rio Almécegas at Cachoeira de Almécegas II, tributary of rio dos Couros, rio Tocantins basin, 14°11’11’’S 47°36’15’’W, 28 Nov 2012, J. L. Birindelli, F. C. Dagosta, M. V. Loeb & C. Santos.

Paratypes. All from Brazil, Goiás, Alto Paraíso de Goiás. MNRJ 52533 , 4 , 28.7–41.9 mm SL ; MZUSP 114056 , 60 (2 cs), 14.9–48.7 mm SL; ZUEC 17332 , 3 , 33.8–37.6 mm SL, collected with holotype. MZUSP 114058 , 1 , 36.6 mm SL, rio dos Couros at Cachoeira São Bento , tributary of rio Tocantins basin, 14°09’38’’S 47°35’38’’W, 28 Nov 2012, J. L. Birindelli, F. C. Dagosta, M. V. Loeb & C. Santos. UFRGS 9954 , 2 , 33.8–40.9 mm SL, rio das Cobras at road between Alto Paraíso de Goiás to the Chapada dos Veadeiros National Park , 14°09’39”S 47°37’55”W, 25 May 2008 , T. P. Carvalho & F. C. Jerep . UFRGS 11257 , 9 , 22.8–39.9 mm SL, rio dos Couros, Portal da Chapada, near Fazenda São Bento , tributary of rio Tocantinzinho , 14°09’58”S 47°35’43”W, 10 Sep 2009, G. Frainer, F. R. Carvalho & V. A. Bertaco .

Diagnosis. Characidium kalunga can be distinguished from its cis-Andean congeners, except C. alipioi Travassos, 1955 , C. amaila Lujan, Agudelo-Zamora, Taphorn, Booth & López-Fernández, 2013 , C. boavistae Steindachner, 1915 , C. bolivianum Pearson, 1924 , C. crandellii Steindachner, 1915 , C. duplicatum Ambruster, Lujan & Bloom, 2021 , C. cricarense Malanski Sarmento-Soares, Silva-Malanski, Lopes, Ingenito & Buckup, 2019 , C. declivirostre Steindachner, 1915 , C. fasciatum Reinhardt, 1867 , C. gomesi Travassos, 1956 , C. grajahuense Travassos, 1944 , C. hasemani Steindachner, 1915 , C. helmeri Zanata, Sarmento-Soares & Martins-Pinheiro, 2015 , C. iaquira Zanata, Ohara, Oyakawa & Dagosta, 2020 , C. japuhybensis Travassos, 1949 , C. kamakan Zanata & Camelier, 2015 , C. lauroi Travassos, 1949 , C. macrolepidotum (Peters, 1868) , C. oiticicai Travassos, 1967 , C. pterostictum Gomes, 1947 , C. purpuratum Steindachner, 1882 , C. schubarti Travassos, 1955 , C. tamata Agudelo-Zamora, Tavera, Murillo & Ortega-Lara, 2020 , C. timbuiense Travassos, 1946 , C. travassosi Melo, Buckup & Oyakawa, 2016 , C. vidali Travassos, 1967 , and C. wangyapoik Ambruster, Lujan & Bloom, 2021 , by lacking scales on the isthmus (vs. isthmus completely scaled), from C. alipioi , C. amaila , C. boavistae , C. bolivianum , C. crandellii , C. cricarense , C. declivirostre , C. fasciatum , C. gomesi , C. grajahuense , C. hasemani , C. helmeri , C. iaquira , C. japuhybensis , C. kamakan , C. lauroi , C. macrolepidotum , C. oiticicai , C. pterostictum , C. purpuratum , C. schubarti , C. tamata , C. timbuiense , C. travassosi , C. vidali by having a single row of dentary teeth (vs. dentary teeth in two rows, internal row with minute conical teeth), and from C. duplicatum and C. wangyapoik by having the scalelles are extending from

isthums to anterior margin of cleithra (vs. scalelles extending on isthmus, area between pectoral fins and part of belly to level of pelvic fins). It can be further distinguished from its congeners, except C. heirmostigmata da Graça & Pavanelli, 2008 , C. papachibe Peixoto & Wosiacki, 2013 , C. satoi Melo & Oyakawa, 2015 , and C. serrano Buckup & Reis, 1997 , by having vertical bars on body that are disconnected dorsally, and from those species by having the bars on body as deep as wide, forming blotches two to four scales wide (vs. blotches vertically elongated, and of one scale width in C. heirmostigmata , C. papachibe , and C. serrano , or blotches forming oval dots, V-shaped, W-shaped, or diamond-shaped marks along and ventral to the lateral line in C. satoi ), and bars not obliquely oriented (vs. bars oblique in C. heirmostigmata , C. papachibe , and C. serrano ), and from all congeners by the presence of a saddle mark at the base of the second to eighth dorsal-fin rays. Osteologically, C. kalunga is diagnosed by having the first and second anal-fin proximal radials fused and contacting the third hemal spine (vs. separated and intercalated with the hemal spines), and by the third hemal spine branched (vs. all hemal spines unbranched).

Description. Morphometric data for holotype and paratypes summarized in Tab. 1 . Largest specimen examined with 43.9 mm SL. Body fusiform. Dorsal profile moderately convex between tip of snout and dorsal-fin origin; gently arched along dorsal-fin base, nearly straight between dorsal fin and origin of first dorsal caudal-fin procurrent ray; slightly convex along anal-fin base; nearly straight between anal fin and origin of first ventral caudal-fin procurrent ray. Greatest depth of body at dorsal-fin origin.

Snout gently rounded in lateral view, its tip slightly below level of ventral margin of eye. Mouth small, subterminal. Snout-maxillary tip distance equal or slightly shorter than eye diameter; maxilla reaching level of anterior margin of orbit. Orbit circular, margin of orbit free. Nares distinctly separated by fleshy bridge; distance between nares shorter than distance between posterior naris to eye. Dermal flap along entire border of anterior naris, crescent-shaped and restricted to anterior margin of posterior naris.

Pectoral fin reaching vertical through dorsal-fin origin when adpressed to body; pectoral-fin rays iii,7 (1), iii,7,i (2), iii,8,i (6), iii,9,i* (5), iv,5,i (1), iv,6,i (1), iv,7,i (4), iv,7,ii (1), iv,8 (2), or iv,8,i (3). Pelvic fin barely reaching anal-fin origin; pelvic-fin rays i,6,i (1), i,7 (1), i,7,i (6), i,7,ii* (1), ii,5,i (2), ii,5,ii (3), ii,6,i (9), ii,7,i (1), iii,6 (1), or iii,7,i (1). Dorsal-fin rays ii,5,i (1), ii,8 (3), ii,9 (1), iii,7,i (2), iii,8 (10), iii,9 (3), or iv,8* (6), last dorsal-fin ray simple, not adnate (2 cs); dorsal-fin supranumerary element 1 (2 cs). Anal fin not reaching ventral caudal-fin procurrent rays; distal margin of anal fin rounded; anal-fin rays ii,5,i (1), ii,6 (1), ii,7 (2), iii,4 (1), iii,5 (15), iii,6 (2), iii,7* (1), iv,4 (1) or iv,5 (2); last anal-fin ray adnate (2 cs); anal-fin supranumerary element 1 (2 cs). Principal caudal-fin rays i,7,8,i (1), i,7,8,ii (1), i,8,7,ii (1), i,8,8,ii (2), i,8,9,i (3), i,9,8,i (1), ii,2,i,5-4,i,5,i (1), ii,6,8,ii (1), ii,7,8,i (1), ii,7,8,ii (10), ii,7,9,i* (3), or ii,7,9,ii (1). Adipose fin absent (1), or present* (25).

Scales cycloid; parallel radii present only on posterior field of scales. Lateral line usually complete; scales along longitudinal row 35 (2), 36 (11), or 37* (13) scales. Perforated scales in lateral line 33 (1), 35 (1), 36 (11), or 37* (13). Scales series above lateral line 4 (5) or 5* (21). Scales below lateral line 4 (1) or 5* (25). Pre-dorsal scale series 12* (5), 13 (11), or 14 (10). Circumpeduncular scales 13 (1) or 14* (25). Scales between anus and anal-fin origin 2* (8), 3 (18), or 4 (1). Isthmus lacking scales to anterior margin of cleithrum.

Premaxillary teeth 5 (3), 6* (19), or 7 (3), all conical, arranged in single row, decreasing in size posteriorly ( Fig. 3A ). Maxillary teeth absent. Dentary teeth 8 (6), 9 (7), 10 (6), 11* (4) or 12 (2), all conical, arranged in single row, decreasing in size posteriorly ( Fig. 3B ). Ectopterygoid teeth 2 (2 cs), conical. Mesopterygoid edentulous (2 cs). Branchiostegal rays 4 (2 cs); 3 attached to anterior ceratohyal (2 cs) and 1 attached to posterior ceratohyal (2 cs). Total gill rakers 10 (1 cs) or 11 (1 cs); gill rakers on basibranchial 2 (1 cs) or 3 (1 cs); gill rakers on ceratobranchial 5 (1 cs) or 6 (1 cs); and gill rakers on epibranchial 4 (1 cs) or 5 (1 cs). Parietal branch of supraorbital laterosensory canal present (2 cs), not reaching parietal bone (1 cs) or reaching parietal bone (1 cs). Fontanel triangular, limited anteriorly by frontals, laterally by frontals and parietals, and posteriorly by supraoccipital (2 cs, Fig. 3C ).

Precaudal vertebrae 21 (1 cs) or 20 (1 cs); total vertebrae 37 (2 cs). Supraneurals 5 (1 cs) or 6 (1 cs). Hypurals 6 (2 cs). Epurals 2 (1 cs) or 3 (1 cs). Upper caudal-fin procurrent rays 8 (1 cs) or 9 (1 cs); lower caudal-fin procurrent rays 7 (1 cs) or 8 (1 cs). Uroneural 1 (2). Postcleithrum 1 enlarged, oval, anterodorsally elongated, and connected dorsally

to ventral tip of supracleithrum; postcleithrum 2 triangular, anterodorsally elongated, connected dorsally to posterior cleithral process; postcleithrum 3 slender and elongated, rib like, connected dorsally to postcleithrum 1 (2 cs, Fig. 4A ). Dorsal-fin pterygiophores 9 (1 cs) or 10 (1 cs), all disconnected, intercalating between neural spines from twelfth to eighteenth vertebrae (1 cs) or eleventh to eighteenth vertebrae (1 cs). Anal-fin pterygiophores 7 (2 cs), first and second proximal radials fused medially and contacting hemal spine of third caudal vertebra, remaining pterygiophores disconnected and inserting on musculature intercalating between hemal spines of third and fourth, fourth and fifth, and fifth and sixth caudal vertebrae ( Fig. 4B ).

Humeral hiatus of obliquus superioris and obliquus inferioris muscles well developed, filled with fatty tissue and not visible externally by transparency. Humeral hiatus ovalshaped, with two chambers divided by pleural rib of fifth vertebra, anterior chamber covered by connective tissue membrane; limited dorsally by lateralis superficialis, posteroventrally by obliquuus inferioris and posterodorsally, ventrally and anteriorly by obliquus superioris. Lateral line nerve passing along dorsal margin of humeral hiatus and continuing along midlateral horizontal septum ( Fig. 5 ).

Coloration in alcohol. General ground color tan yellow, dark brown dorsally and pale beige ventrally. Dorsal part of head snout and skull dark brown; lateral and ventral part of snout, distal portion of upper jaw, lower jaw, cheek, ventral part of opercle, and branchiostegal membranes lighter, with scarcely spaced melanophores. Scales on dorsal portion of body with melanophores more concentrated on distal margin, providing reticulated aspect on dorsal portion of body. Sides of body gradually lighter from dorsal to ventral surface, with ventral parts of belly and caudal peduncle light beige.

Preorbital stripe thin, extending obliquely between proximal third of upper jaw and anterior margin of eye. Postorbital stripe thicker than preorbital and longitudinal stripes, extending horizontally between posterior margin of eye and dorsal margin of opercle. Longitudinal stripe having less than one scale width, extending horizontally between dorsal margin of opercle to posterior portion of caudal peduncle, but not reaching base of caudal-fin rays. Humeral blotch oval located immediately posterior to upper corner of opercle, with three scales depth and two scales wide. Basicaudal spot inconspicuous and not easily discernible, positioned at middle caudal-fin rays.

Bars on body seven to nine, present in most specimens examined. Bars on dorsum irregularly distributed and disconnected from lateral portion, often fused and forming irregular longitudinal dorsal lines between head and dorsal fin. Lateral portion of bars disconnected from dorsal portion and not connected in ventral midline, forming large square blotches on sides of body but, in larger specimens, inconspicuous and not easily discernible ( Fig. 2F ).

Pectoral and pelvic fins mostly hyaline, with melanophores concentrated on dorsal margin of fin rays. Anal fin hyaline. Dorsal-fin mostly hyaline except for one middle, longitudinal dusk and inconspicuous stripe, and one discernible saddle-like mark on base of fourth to eight dorsal-fin rays. Caudal fin mostly hyaline, or with irregularly distributed melanophores on proximal two thirds. Adipose-fin hyaline, with scarce melanophores.

Coloration in life. General pigmentation like that of preserved specimens. Live specimens with ground color brownish, and square blotches on flanks more easily discernible ( Fig. 6 ).

Ontogenetic variation of pigmentation. In smaller specimens (<19 mm SL), the body is pale beige and the blotches are poorly marked and barely indistinguishable ( Figs. 2A–B ); in larger specimens (>20.0 mm SL), the ground color becomes yellowish and the blotches well defined ( Figs. 2C–E ); and the largest specimen examined (48.3 mm SL) lacks bars, has the overall body pattern dusky, including the areas on cheeks and fins and the blotches are merged into the background and indistinguishable ( Fig. 2F ). The humeral and basicaudal spots and the saddle mark at base of dorsal fin are visible in all specimens examined but are inconspicuous in the largest specimen. The pseudotympanum is visible by skin transparency in smaller were observed in the available specimens.

Geographical distribution. Characidium kalunga is known only from the streams draining the southern portion of the Chapada dos Veadeiros, tributaries of the upper rio Tocantins basin. It was collected in the rio dos Couros and rio Almécegas, but field observations and photographic records also include the rio Preto, upstream from the Salto de 120 Metros waterfall ( Fig. 7 ).

Ecological notes. Characidium kalunga is a bottom dweller species, known from localities with elevation of about 1,200 meters. It inhabits rivers with fast flowing, cold, black water with rocky bottom, characterized by the presence of many rapids, canyons, and relatively large waterfalls, alternating with pools with sandy bottom. Those rivers are often impacted by sudden water flow increase caused by precipitation runoff in the

watershed. The Cerrado vegetation is restricted to the margins, with no aquatic plants present in the river channel ( Fig. 8 ).

Etymology. The specific name honors the Comunidade Quilombola Kalunga, a resilient community of Afro-Brazilians that lives in the Chapada dos Veadeiros area, helping to protect its natural resources. Kalunga also means a sacred place in the African Bantu language. A noun in apposition.

Conservation status. Characidium kalunga has a narrow distribution, with an area of occupancy smaller than 500 km 2. It occurs within the limits of a protected area, the Parque Nacional da Chapada dos Veadeiros. Impacts such as continuing populational decline or extreme fluctuations of the extent of occurrence, area of occupancy, quality of habitat, number of locations or subpopulations, or number of mature individuals were not observed. Therefore, in accordance with the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Subcommittee, 2019), C. kalunga is categorized as Least Concern ( LC).

Figures

FIGURE 1 | Characidium kalunga in lateral (top), ventral (middle) and dorsal (bottom) views, holotype, MZUSP 125824, 40.5 mm SL, rio Almécegas at Cachoeira de Almécegas, Chapada dos Veadeiros, Alto Paraíso de Goiás, Brazil.

FIGURE 2 | Paratypes of Characidium kalunga, MZUSP 114054, A. 15.3 mm SL, B. 18.2 mm SL, C. 21.4 mm SL, D. 29.7 mm SP, E. 30.9 mm SL, and F. 48.7 mm SL. Scale bar = 5 mm, Chapada dos Veadeiros, Goiás, Brazil.

FIGURE 3 | Osteological characteristics of head in Characidium kalunga, MZUSP 114054, paratype. A. Right upper jaw in medial view; B. Right dentary in medial view; C. Skull in dorsal view. Abbreviations: ANT, antorbital; DEN, dentary; dent, dentary teeth; dentr, replacement dentary teeth; DPSO, dorsal process of the supraoccipital; ESC, extrascapular; FR, frontal; fo, fontanel; IO 1–6, infraorbitals 1 to 6; METH, mesethmoid; MX, maxilla; NA, nasal; PAR, parietal; PMX, premaxilla; pmxt, premaxilarry teeth; pmxtr, replacement premaxillary teeth; PTE, pterotic; POST, posttemporal; SUO, supraorbital; soc, supraorbital canal; and socpb, parietal branch of the supraorbital canal. Scale bar = 1 mm.

FIGURE 4 | Osteological characteristics of fins in Characidium kalunga, MZUSP 114054, paratype. A. Left pectoral girdle in lateral view; B. Caudal peduncle in lateral view – left intermuscular bones removed. Abbreviations: arrow, position of anus; asterisk, first caudal vertebra; CEN, centrum; CLE, cleithrum; COR, coracoid; ESC, extrascapular; LLS1, first lateral-line scale; HS3, third haemal spine; MCO, mesocoracoid; NS, neural spine; PCP, posterior cleithral process; PR, pleural rib; PRAF 1+2, fused anal-fin proximal radials 1 and 2; PTC1, postcleithrum 1; PTC2, postcleithrum 2; PTC3, postcleithrum 3; POST, posttemporal; SC, scapula; SCL, supracleithrum. Scale bar = 1 mm.

FIGURE 5 | Humeral hiatus in Characidium kalunga, MZUSP 114054, 42.0 mm SL, paratype. Abbreviations: LLN, lateral-line nerve; LS, lateralis superficialis; OI, obliquus inferioris; OS, obliquus superioris; PR5, pleural rib of fifth vertebra. Scale bar = 1 mm.

FIGURE 6 | Underwater photography of Characidium kalunga in the rio Preto, at the Parque Nacional da Chapada dos Veadeiros, Goiás, Brazil (not collected).

FIGURE 7 | Map of the Chapada dos Veadeiros indicating the known distribution of Characidium: circles represent Characidium kalunga, triangles, C. xanthopterum, and diamonds, C. stigmosum. Black symbols indicate the type locality and white symbols other records.

FIGURE 8 | Habitats of Characidium kalunga at the Chapada dos Veadeiros: A. Type locality, cachoeira das Almécegas II, at rio Almécegas, tributary of rio dos Couros; B. Rio Preto, at Parque Nacional da Chapada dos Veadeiros.