Leporinus maxakali, new species

(Fig. 1, Table 1)

Leporinus sp. — Pugedo et al. 2016: 343 (DNA Barcode analysis).

Holotype. MZUEL 20000 (123.3 mm SL), Brazil, Minas Gerais, Minas Novas, rio Jequitinhonha basin, rio Fanado, tributary of rio Araçuaí, at Barragem das Almas (dam), c. 2 km upstream from city, 17°14'16.0"S 42°35'26.6"W; 5 Jul 2016, J. L. O. Birindelli, F. C. Jerep, E. Santana & R. H. C. Nascimento.

Paratypes. All from Brazil, Minas Gerais, rio Jequitinhonha basin. ANSP 206297 (1, 82.1 mm SL); MZUEL 15000 (1, 91.4 mm SL), collected with holotype. LISDEBE 6653 (2, 74.9–77.1 mm SL), same locality as holotype; 21 Oct 1987, G. B. Santos, A. S. Soares & A. J. Alves. LISDEBE 6654 (4, 65.5–77.8 mm SL), Chapada do Norte, rio Capivari, tributary of rio Araçuaí, 17°00'12.2"S 42°35'15.1"W; 18 Oct 1987, G. B. Santos, A. S. Soares & A. J. Alves. LISDEBE 6655 (1, 73.6 mm SL), Minas Novas, rio Fanado, tributary of rio Araçuaí, at bridge of city, 17°13'13.6"S 42°35'46.5"W; 16 Oct 1987, G. B. Santos, A. S. Soares & A. J. Alves. LISDEBE 6656 (1, 90.4 mm SL), same locality as holotype; 19 Oct 1987, G. B. Santos, A. S. Soares & A. J. Alves. MZUEL 7033 (2, 25.4–25.9 mm SL), Olhos d'Água, Córrego Labatu, at Cachoeira Labatu, 17°26'3.6"S 43°36'57.2"W; 6 Sep 2012, F. Andrade Neto, T. Barroso & I. G. Prado. MZUEL 7210 (2, 35.1–44.0 mm SL), Itamarandiba, rio Itamarandiba, 18°01'30.2"S 42°50'51.6"W; 15 Sep 2012, F.Andrade Neto, T. Barroso & I. G. Prado. MZUEL 10687 (1, 87.5 mm SL), Capelinha, Ribeirão Santo Antônio, tributary of rio Araçuaí, 17°46'17.1"S 42°36'58.1"W; 24 Jun 2014, F. Andrade Neto, T. Barroso & I. G. Prado. MZUSP 93719 (2, 80.8–83.2 mm SL), Minas Novas, rio Fanado, tributary of rio Araçuaí, at bridge of city, 17°13'13.6"S 42°35'46.5"W; 12 Apr 2007, J. L. Birindelli, O. T. Oyakawa & L. M. Sousa. MZUSP 93732 (2, 74.6–90.7 mm SL), Minas Novas, rio Fanado, tributary of rio Araçuaí, near Balneário Dr. Urias Serra Costa, 17°14'15.0"S 42°35'25.0"W; 13 Apr 2007, J. L. Birindelli, O. T. Oyakawa & L. M. Sousa. NUP 15527 (2, 100.4– 128.6 mm SL), Minas Novas, rio Araçuaí, 17°07'36.0"S 42°41'28.0"W; 29 Jul 2013, T.C. Pessali.

Diagnosis. Leporinus maxakali is distinguished from all other Anostomidae, except Brevidens striatus Kner, 1858, Hypomasticus despaxi (Poyo, 1943), H. lineomaculatus (Birindelli, Peixoto, Wosiacki & Britski, 2013), H. megalepis (Günther, 1864), Leporinus amae Godoy, 1980, L. bahiensis, L. bistriatus Britski, 1997, L. britskii Feitosa, Santos & Birindelli, 2011, L. desmotes Fowler, 1914, L. enyae Burns, Chatfield, Birindelli & Sidlauskas, 2017, L. gutatus Birindelli & Britski, 2009, L. jatuncochi Ovchynnyk, 1971, L. marcgravii, L. melanopleura, L. melanopleurodes, L. microphthalmus, L. microphysus Birindelli & Britski, 2013, L. moralesi Fowler, 1942, L. multimaculatus Birindelli, Teixeira & Britski, 2016, L. octofasciatus Steindachneri, 1915, L. octomaculatus Britski & Garavello, 1993, L. parvulus Birindelli, Britski & Lima, 2013, L. reticulatus Britski & Garavello, 1993, L. sexstriatus Britski & Garavello, 1993, L. taeniatus Lütken, 1875, L. taeniofasciatus Britski, 1997, L. tigrinus Borodin, 1929, L. tristriatus Birindelli & Britski, 2013, L. villasboasorum Burns, Chatfield, Birindelli & Sidlauskas, 2017, and Megaleporinus garmani, for having three premaxillary teeth and four dentary teeth (vs three premaxillary teeth and three dentary teeth in Abramites, Megaleporinus and Leporinus amblyrhynchus, or four premaxillary teeth in remaining species). The new species is distinguished from Hypomasticus despaxi, H. lineomaculatus, H. megalepis, Leporinus microphysus and L. paranensis by having 12 scale rows around caudal peduncle (vs. 16), and subterminal mouth (vs. subinferior). The new species is distinguished from remaining species (except L. bahiensis, and L. inexpectatus) by having three large midlateral dark blotches on body (vs. dark midlateral stripe on body in L. amae, L. bistriatus, L. britskii, L. melanopleura, L. melanopleurodes, L. moralesi, L. parvulus, L. sexstriatus, L. striatus, L. taeniatus, L. taeniofasciatus, dark vertical bands on body in L. desmotes, L. enyae, L. jatuncochi, L. octofasciatus, L. tigrinus and L. villasboasorum, seven to nine dark midlateral blotches on body in L. guttatus, L. marcgravii, L. microphthalmus and L. octomaculatus, irregular blotches scattered on body in L. reticulatus, or anterior portion of body with five rounded blotches forming an X in L. multimaculatus). The new species is distinguished from L. bahiensis and L. inexpectatus by having posterior portion of upper lip red in life (vs. tan), dark blotch above pectoral-fin insertion separated from gill opening by one or two scales (vs. dark blotch above pectoral-fin insertion adjacent to gill opening), relatively small eyes, 20–25% in head length in specimens larger than 80 mm SL (vs. relatively large eyes,>25% of head length in specimens larger than 80 mm SL), and small body size, not reaching 150 mm SL (vs relatively large body size, reaching 250 mm SL).

Description. Morphometric data is provided in Table 1. Small size, relative to congeners; largest examined specimen 128.6 mm SL. Head and body elongate and moderately compressed. Dorsal profile gently convex from snout tip to dorsal-fin origin, slightly convex along dorsal-fin base, approximately straight from dorsal-fin end to adipose-fin origin, and slightly concave from adipose-fin origin to anteriormost dorsal caudal-fin procurrent ray. Ventral profile slightly to strongly concave from lower jaw to vertical through anterior margin of eye, straight to slightly concave from that point to vertical through posterior margin of opercle, convex from latter point to anal-fin origin, slightly convex along anal-fin base, and gently concave from anal-fin end to anteriormost ventral caudal-fin procurrent ray. Greatest body depth slightly anterior to dorsal-fin origin.

Mouth subterminal, its cleft longitudinally aligned with ventral margin of eye. Snout rounded, anteriorly blunt. Premaxillary with three* (n = 19) incisiform teeth gently decreasing in size from the symphyseal tooth. Dentary with four* (18) incisiform teeth also gently decreasing in size laterally.

Scales cycloid. Lateral line complete with 34 (4), 35* (11) or 36 (5) perforated scales, extending from supracleithrum to base of middle caudal-fin rays. Horizontal scale rows between dorsal-fin origin and lateral line three (6) or four* (12). Horizontal scale rows between lateral line and pelvic-fin origin three (15) or four* (3). Horizontal scale rows around caudal peduncle 12 (18). Predorsal scales from dorsal-fin origin to tip of supraoccipital spine 10 (7) or 11* (11).

Dorsal-fin rays ii,9 (1), ii,10 (7), iii,9* (10). Dorsal-fin origin slightly anterior to middle of standard length and to vertical through pelvic-fin origin; its distal margin gently concave. Adipose fin small, teardrop shaped, its origin approximately at vertical through base of last anal-fin ray. Pectoral-fin rays i,13 (1), i,14 (7), i,15* (9) or i,16 (1); fin tip extending approximately half the distance between origins of pectoral- and pelvic-fin; its distal margin slightly convex. Pelvic-fin rays i,8* (18); its distal margin slightly convex. Anal-fin rays ii,8* (18); fin origin approximately at vertical through fourth scale anterior to adipose-fin origin, when adpressed fin not reaching caudal-fin rays base; its distal margin slightly concave or straight. Principal caudal-fin rays i,8,9,i* (18). Caudal fin forked, lobes rounded, upper lobe slightly longer than lower lobe.

Color in alcohol. Ground color of head and body light brown and counter shaded. Body with three dark midlateral blotches, more conspicuous than smaller dark blotches, slightly reduced in size posteriorly, and formed by dermal and epidermal pigment. Body with additional dark blotches, less conspicuous, formed by dermal pigment, roughly arranged in bands in small specimens (around 60 mm SL), including a dark blotch above pectoral-fin origin that is separate from gill opening by one or two scales. Ventral surfaces of head and body pale to cream. Dorsal and caudal fins mainly tan or tan with dark marks, adipose fin mainly tan or with dark distal margin. Pectoral, pelvic and anal fins hyaline or tan.

Color in life. Ground color of body more yellowish than described above; pectoral, pelvic and anal fins orange, dorsal and caudal fins dark orange, and adipose fin red with dark margin. Posterior portion of upper lip with conspicuous red spot. Dorsal portion of iris also with red spot.

Distribution. Leporinus maxakali is only known from tributaries of the upper rio Jequitinhonha basin, Minas Gerais state, eastern Brazil (Fig. 2).

Ecological notes. Specimens of Leporinus maxakali were collected in creeks and small-sized rivers with fast, in both clear and black waters, and rocky bottom (Fig. 3).

Conservation Status. The species is endemic to the upper rio Jequitinhonha basin, occurring in an area smaller than 20,000 km ², with the polygon encompassing all known occurrence sites covering approximately 7,000 km ². Large portions of Minas Gerais State, particularly the rio Jequitinhonha basin, are subject to multiple anthropogenic threats, including human settlement, pollution, agricultural expansion, and mining. Recent inventories in the Parque Estadual do Rio Preto did not reveal the presence of this species inside the protected area, but only on its borders. Consequently, populations of L. maxakali may be severely fragmented, as several rivers in the region are regulated by small to medium-sized reservoirs, and its area of occupancy, extent of occurrence, and habitat quality are inferred to be in continuous decline. It is likely that this species has experienced a sustained reduction in abundance and distribution in recent years. Therefore, once assessed, the species could potentially be assigned to one of the IUCN threatened categories.

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Genetic analyses. The genetic distance among all sampled species (Tab. 3) was relatively high (>2%), whereas intraspecific distances were low (<1.2%). The bPTP species delimitation analysis identified 15 Molecular Operational Taxonomic Units (MOTUs), with all specimens of the new species consistently recovered as a single MOTU. The bPTP species delimitation analysis results differed from morphology-based identifications by revealing additional MOTUs within L. amblyrhynchus, L. bahiensis, and L. friderici. The phylogenetic reconstruction recovered a monophyletic clade composed of L. amblyrhynchus, L. maxakali, L. melanopleura, L. melanopleurodes, and L. microphthalmus (Fig. 4).

Etymology. The specific epithet honors the Maxakalí people,an indigenous group inhabiting the rio Jequitinhonha basin in Minas Gerais State, Brazil (Paraíso 1994). Treated as a noun in apposition.