Bunocephalus hertzi, Esguícero & Castro & Pereira, 2020

Esguícero, André L. H., Castro, Ricardo M. C. & Pereira, Thiago N. A., 2020, Bunocephalus hertzi, a new banjo catfish from the upper Rio Paraná basin, Brazil (Siluriformes: Aspredinidae), with the redescription of Bunocephalus larai Ihering 1930, Zootaxa 4742 (1), pp. 105-116 : 110-114

Bunocephalus hertzi , new species

( Fig. 4 , Table 1 )

urn:lsid:zoobank.org:act:38D4E9B5-4A9E-4EAA-8570-B36F02C40D8A

Holotype: LIRP 9861 , 53.8 mm SL; Brazil, São Paulo State: Luis Antônio Municipality: upper Rio Paraná, Rio Pardo , Rio Mogi-Guaçú , near the Estação Ecológica de Jataí , 21º36’44”S 47º49’09”W; A. L. H. Esguícero, R. M. C. Castro, T. N. A. Pereira & H. F. Santos, 18 Sep 2012.

Paratypes: DZSJRP 12210, 1, 52.1 mm SL; Brazil: São Paulo State: Jaboticabal Municipality: Rio Pardo, Rio Mogi-Guaçu , Córrego Rico , 21º15’56”S 48º14’12”W; E. Takahashi, Dec 2008 .− LIRP 9058 , 1 CS, 47.6 mm SL , same data as holotype.− LIRP 9860 , 1 , 54 , 4 mm SL; Brazil: São Paulo State: Cajuru Municipality: Rio Pardo, Fazenda Santa Carlota , 21º26’50”S 47º16’57”W; H. F. Santos & A. Zanata, 1 Jan 1990 .− LIRP 11302 , 2 , 53.9 – 52.9 mm SL; Brazil , São Paulo State: Luis Antônio Municipality: Rio Pardo, Rio Mogi-Guaçú , near the Estação Ecológica de Jataí , 21º36’44”S 47º49’09”W; H. F. Santos, A. L. H. Esguícero & T. N. A. Pereira, 15 Oct 2014 .− MZUEL 9521 , 1 , 48.5 mm SL; Brazil: Paraná State: Santa Amélia Municipality: Rio Paranapanema, Rio das Cinzas , Ribeirão Laranjinha , 23º17’49”S 50º28’43.2”W; Galindo et al, 19 Dec 2011 .− MZUEL 16067 , 2 , 37.8–48.9 mm SL; Brazil : Paraná State: Santa Amélia Municipality: Rio Paranapanema, Rio das Cinzas , Ribeirão Laranjinha , 23º17’49”S 50º28’43.2”W.− MZUEL 17088 , 1 , 54.4 mm SL; Brazil : Minas Gerais State: Patrocínio Municipality: Rio Paranaíba, Córrego Nhame , 18º59’14”S 46º41’37”W; Salvador, 27 Feb 2013 .− NUP 3880, 6, 49.8–57.4 mm SL; Brazil: Paraná State: Maringá Municipality: Rio Paranapanema, Rio Pirapó , 23º19’36”S 51º50’41”W; Nupélia, 17 Sep 2004 .− NUP 9352, 2, 48.7–52.1 mm SL; Brazil: Mato Grosso do Sul State: Itaporã Municipality: Rio Ivinhema, Rio Santa Maria , Córrego Sardinha , 22º3’36”S 54º47’14”W; Súarez et al., 8 Dez 2008.− NUP 17492 , 1, 53.8 mm SL; Brazil: Paraná State: Maringá Municipality: Rio Paranapanema, Rio Pirapó , 23º18’10”S 51º51’43”W; Deprá et al., 30 Nov 2012.− NUP 17498 , 3, 56.5–57.9 mm SL; Brazil: Paraná State: Maringá Municipality: Rio Paranapanema, Rio Pirapó , 23º24’3”S 51º38’26”W; Ghisi et al., 5 Dec 2012 .

Diagnosis. Bunocephalus hertzi can be distinguished from all its congeners, except from B. larai and B. minerim , by the absence of an epiphyseal bar (vs. present). From B. minerim , it can be diagnosed by the presence of 10 principal caudal-fin rays (vs. 9). Bunocephalus hertzi can be further distinguished from B. larai , the only congener that also occurs in the upper Rio Paraná basin, by the longer coracoid process size (11.9–16.2% vs. 6.7–9.8% SL) and the shorter maxillary barbel (54.6–67.4% vs. 73.7–84.6% HL). In addition, B. larai presents skull ornamentation composed by five bony protuberances between the posterior end of the occipital and the origin of the dorsal fin (vs. four).

Description. See Fig. 4 for general appearance. Morphometric data of holotype and 21 paratypes are presented in Table 1 . Head dorsoventrally compressed, straight and posterodorsally inclined from tip of snout to posterior tip of occipital. Body widest at cleithrum, greatest depth slightly ahead of dorsal-fin origin. Posterodorsal profile of body straight and posteroventrally inclined from dorsal-fin origin to near base of caudal-fin, becoming slight concave anteriorly to base of caudal-fin. Ventral profile of body convex from tip of snout to near pelvic-fin origin, straight to first anal-fin ray, and slightly concave from anal-fin origin to base of caudal-fin.

Skull ornamentation represented by five dorsomedial bony protuberances ( Fig. 2 ): a protuberance located at posterodorsal end of supraoccipital, formed by posterior dorsal tip of supraoccipital and anterodorsal tip of complex centrum of Weberian apparatus; three well developed protuberances linearly distributed along dorsal edge of complex centrum of Weberian apparatus; and a prominent protuberance at dorsal face of middle nuchal plate, just anterior to first dorsal-fin origin. Frontals in contact anteriorly to cranial fontanel. Epiphyseal bar between paired frontals absent.

Eye small, without free orbital margin, located dorsally in anterior half of head. Anterior nostril tubular, located at anterior edge of snout, projecting beyond upper lip; posterior nostril as small opening located anteromedially to eye. All barbels unbranched; maxillary barbel extending to pectoral-fin origin, rarely surpassing this point; two pairs of mental barbels, both shorter than maxillary barbels; anterior mental barbel shortest, its length less than half length of posterior mental barbel. Mouth subterminal, upper lip more prominent relative to lower lip. Gill openings small, restricted to two ventral valvular slits covered by fleshy skin flaps, located just anterior to pectoral-fin spines insertions. Gill membranes united to isthmus. Axial slit pore present, just underneath posterior cleithral process. Small genital papillae just posterior to anus. Unculiferous tubercles densely distributed all over integument; larger tubercles on posterior portion of body longitudinally aligned, forming defined rows on caudal-peduncle, one middorsal, two above lateral-line, and one over lateral line.

Dorsal-fin i4*(21); located slightly anterior to mid-standard length. Dorsal-fin spinelet absent; two thirds of last dorsal-fin ray adnate to dorsum by membrane. Adipose-fin absent. Anal-fin ii5(3), ii6*(4), iii5(12), or iii6(2); its origin just posterior to tip of longest ray of abducted pelvic-fin; two thirds of last anal-fin ray adnate to ventral region of caudal peduncle by membrane. Pectoral-fin I5*(21); its origin just posterior to gill opening, tip reaching pelvic-fin origin; pectoral spine straight, bearing recurved serrations all over anterior and posterior margins; serrations increasing in number according to body size, maximum of fifteen serrations over each margin. Pelvic-fin i5*(21); its origin just posterior to vertical through dorsal-fin origin. Principal caudal-fin rays i8i; caudal-fin distal profile convex. Caudal-fin unbranched rays shorter than branched rays. Two procurrent caudal-fin rays, first one vestigial. Total vertebrae 33(2), 34(10), 35*(6), 36(2), or 37(1). Ribs 4*(16) or 5(5). Lateral-line canal complete, not reaching caudal-fin origin; presence of simple ossified tubes, each bearing small hook at posterior region of tube.

Color in alcohol. Ground color of dorsal region of body and head dark brown, ventral region light brown. Three black dorsal saddles on body; first saddle conspicuous, located at and as wide as dorsal-fin base, extending to ventral region, not reaching pelvic-fin origin; and two inconspicuous saddle on posterior body region, last one anterior to caudal-fin origin. Pectoral-fin brown, pelvic and anal fins light yellow with dark blotches, dorsal-fin dark brown with light yellow distal portion, first dorsal-fin ray yellow. Caudal-fin black at middle rays with light yellow distal portion, bordered by yellowish margin covering two most dorsal and three most ventral caudal-fin rays. All barbels light brown with dark brown blotches.

Color in life. Observations based on photographs of live, recently collected specimens, in aquaria. Coloration as in preserved specimens.

Distribution. Bunocephalus hertzi is known from the upper Rio Paraná basin, with registered occurrence at the Rio Pardo (Rio Pardo and Rio Mogi-Guaçu, at Rio Grande basin), Rio Paranapanema (Rio Pirapó and Rio Laranjinha), Rio Paranaíba (Córrego Nhame), and Rio Ivinhema (Rio Santa Maria) basins ( Fig. 3 ).

Environmental notes. The Rio Mogi-Guaçu main channel at the type locality is relatively large (84–87 m width) and moderately deep (approximately 2 m in some sites), characterized by lentic waters, marginal sandbanks and floating macrophytes mats. Waters are turbid and the river bottom is composed by sand and a high amount of vegetal debris. The specimens of Bunocephalus hertzi were collected among masses of vegetal debris, at the river margins, during the low water season, in a particularly dry year.

Etymology. The specific epithet, hertzi , honors Hertz Figueiredo dos Santos, Biologist at the Laboratório de Ictiologia de Ribeirão Preto -LIRP, co-discoverer of the new species, and in deep appreciation for his approximately three decades of unfailing contribution to the studies of Neotropical fishes.

Figures

FIGURE 2. Skull ornamentation of CS Representatives of A—Bunocephalus hertzi, LIRP 9058, 47.6 mm SL; B—B. larai, MZUEL 114, 53.7 mm SL. Arrows indicate bone protuberances at supraoccipital bone (so), complex centrum (cc) of the Weberian apparatus, and at nuchal plate (np).

FIGURE 3. Map of the southeastern South America showing the geographic distribution of Bunocephalus larai (type locality- grey triangle; non-types- grey squares) and B. hertzi (holotype black triangle; paratypes- black circles) in the upper Rio Paraná basin. 1—Rio Paranaíba; 2—Rio Grande; 3—Rio Paraná; 4—Rio São Marcos; 5—Rio Capivari; 6—Rio Pardo; 7—Rio Mogi-Guaçu; 8—Rio Piracicaba; 9—Rio Tietê; 10—Rio Ivinhema; 11—Rio Paranapanema; 12—Rio Pirapó; 13—Rio Tibagi; 14—Rio das Cinzas.

FIGURE 4. Bunocephalus hertzi, LIRP 9861, holotype, 53.8 mm SL; Brazil, São Paulo: upper Rio Paraná, Rio Pardo, Rio Mogi-Guaçú.

Tables

TABLE 1. Morphometric data of 11 nontypes of Bunocephalus larai, and of holotype and 21 paratypes of Bunocephalus hertzi. SD, standard deviation. Values of holotype included in the species ranges.

	B. larai				B. hertzi
	range	mean	SD	holotype	range	mean	SD
Standard length (mm)	48.6–59.1			53.8	38.4–58.9
Percent of standard length
Head length	32.5–37.3	35.2	1.5	35.9	32.6–38.8	36.7	1.5
Prepectoral length	22.1–25.7	23.8	1.3	26.1	18.1–26.9	24.0	1.8
Cleithral width	28.2–32.2	30.0	1.2	31.4	17.3–32.5	30.4	3.3
Maximum head depth	14.1–17.8	15.9	1.3	14.1	13.5–20.8	16.6	2.1
Pectoral-spine length	21.8–25.0	23.2	1.0	25.0	17.5–28.2	23.5	2.5
Distance between coracoid processes	19.5–23.3	22.0	1.2	21.2	18.6–26.2	21.9	2.2
Coracoid process length	6.7–9.8	8.0	0.9	13.3	11.9–16.2	13.1	1.2
Distance between cleithral processes	21.7–24.9	23.3	1.2	22.9	20.6–27.2	23.3	1.7
Cleithral process length	11.7–15.0	13.4	1.1	16.8	14.7–19.6	16.9	1.2
Predorsal length	35.1–44.7	41.6	2.8	42.8	24.7–45.6	41.0	4.4
Depth at dorsal-spine insertion	12.0–15.4	13.8	1.4	12.4	10.8–17.2	14.1	1.9
Dorsal-spine length	11.8–16.2	13.3	1.5	13.0	7.4–16.6	13.5	1.9
Prepelvic length	41.5–49.7	46.2	2.5	64.2	42.7–64.2	48.0	4.3
Length of 1st unbranched pelvic- fin ray	11.3–14.4	12.6	0.9	10.2	4.0–13.8	11.3	2.1
Preanal length	57.5–65.7	62.2	2.8	63.7	58.2–70.5	63.7	2.3
Anal-fin base length	14.9–18.9	16.8	1.3	16.4	10.6–19.9	16.6	2.6
Caudal-peduncle length	18.4–25.8	22.0	2.6	20.8	15.5–26.0	19.7	2.6
Caudal-peduncle depth	3.4–5.1	4.2	0.6	4.5	4.1–5.5	4.8	0.4
Caudal -fin length	16.6–20.9	18.6	1.4	20.6	18.8–23.1	20.5	1.0
Percent of head length
Snout length	14.0–21.4	16.7	2.3	15.8	13.4–23.7	17.0	2.4
Eye diameter	4.4–5.7	5.0	0.5	4.8	3.5–5.7	4.8	0.6
Interorbital width	18.6–22.6	20.8	1.6	19.8	18.2–26.8	21.6	2.0
Maxillary-barbel length	73.7–84.6	77.9	3.4	66.1	54.6–67.4	60.1	3.7
Distance between anterior nares	11.5–14.0	13.2	0.9	11.9	10.4–14.0	12.5	0.8
Distance between posterior nares	17.7–22.4	20.0	1.8	20.0	16.7–24.3	19.8	1.7
Mouth width	23.4–28.3	26.2	1.6	22.8	18.0–24.4	21.9	2.7