Moenkhausia lineomaculata, Dagosta, Fernando C. P., Marinho, Manoela M. F. & Benine, Ricardo C., 2015

Dagosta, Fernando C. P., Marinho, Manoela M. F. & Benine, Ricardo C., 2015, A new species of Moenkhausia Eigenmann (Characiformes: Characidae) from the upper rio Juruena basin, Central Brazil, Zootaxa 4032 (4), pp. 417-425 : 418-422

Moenkhausia lineomaculata , new species

( Figs. 1–3 ; Table 1 )

Holotype. MZUSP 117108, 67.8 mm SL, Campos de Júlio, rio Juruena at Fazenda Tiroleza, upper rio Tapajós basin, Mato Grosso State, Brazil, 14º16’37”S 59º5’22”W, K. de Silimon, 19 Sep 2006.

Paratypes. All from Mato Grosso State, Brazil, upper rio Tapajós basin. MZUSP 105953, 3, 14.8–36.6 mm SL, Campos de Júlio, rio Juruena at Fazenda Tiroleza, upstream to the airport, 14º15’47”S 59º5’25”W, K. de Silimon, 19 Sep 2006. MZUSP 106316, 2, 23–66.7 mm SL, same data as holotype. MZUSP 106320, 2, 19.5–27.1 mm SL, Campos de Júlio, swamp between rio Juruena and Cabeceira stream, upstream to the bridge at BR–364 road, 14º39’43”S 59º6’27”W, K. de Silimon, 18 Sep 2006. MZUSP 106322, 3, 18.6–23.5 mm SL, INPA 48035, 3, 26–36.5 mm SL, USNM 427200, 3, 26.1–38.5, Campos de Júlio, rio Juruena at Fazenda Tiroleza, 14º16’38”S 59º5’22”W, K. de Silimon, 19 Sep 2006. MZUSP 106324, 4, 17.7–32.4 mm SL, Campos de Júlio, rio Juruena, stream upstream to the bridge at BR–364 road, 14º39’43”S 59º6’27”W, K. de Silimon, 17 Sep 2006. MZUSP 106325, 1, 35.5 mm SL, Sapezal, rio Juruena at left margin, upstream to the PCH (Small hydropower plant) Santa Lúcia, 13º38’23”S 59º0’28”W, K. de Silimon, 24 Sep 2006. MZUSP 106326, 1, 29.5 mm SL, Sapezal, rio Juruena, upstream to the PCH Santa Lúcia, 13º34’49”S 59º1’48”W, K. de Silimon, 24 Sep 2006. MZUSP 106327, 5, 21.6– 30.4 mm SL, 2 C&S, 30.7–34.9 mm SL, Campos de Júlio, rio Juruena at Fazenda Tiroleza, 14º16’38”S 59º5’22”W, K. de Silimon, 19 Sep 2006. MZUSP 106328, 1, 36.3 mm SL, Sapezal, rio Juruena, downstream to the PCH Ilha Comprida, 13º12’6”S 58º59’3”W, K. de Silimon, 26 Sep 2006. MZUSP 106467, 2, 30.7–41.1 mm SL, Sapezal, rio Juruena at right margin, upstream to the PCH Sapezal, 13º14’47”S 50º0’52”W, K. de Silimon, 22 Sep 2006. MZUSP 107995, 4, 18.4–30.4 mm SL, Sapezal, rio Juruena upstream to the Cachoeirão waterfall, 12º55’35”S 58º55’19”W, K. de Silimon, 6–8 Jul 2006.

Diagnosis. Moenkhausia lineomaculata is readily distinguished from all congeners, except M. cosmops Lima, Britski & Machado , M. cotinho Eigenmann , M. diktyota Lima & Toledo-Piza , M. forestii Benine, Mariguela & Oliveira , M. oligolepis (Günther) , M. sanctaefilomenae (Steindachner) , and M. pyrophthalma Costa by the presence of a reticulated color pattern on body formed by dark pigmentation on the posterior portion of the scales (vs. absence). It is further distinguished from all congeners, except M. cosmops , M. cotinho , M. forestii , M. oligolepis , M. sanctaefilomenae , and M. pyrophthalma by the presence of a light area preceding the dark caudalpeduncle blotch (vs. absence). The new species is distinguished from all the aforementioned species, except M. cotinho , by the presence of longitudinal series of dark dots on body (vs. absence), and from M. cotinho by the humeral blotch evenly pigmented along its length (vs. dorsal portion of the humeral blotch distinctly darker, fig. 5) and by having the longitudinal line formed by subjacent dark pigmentation along horizontal septum starting approximately at the vertical through dorsal-fin origin (vs. starting slightly posterior to the humeral blotch, fig. 5).

Description. Morphometric data presented in Table 1 . Body compressed, moderately elongate. Greatest body depth slightly anterior to dorsal-fin origin. Dorsal profile of head convex from upper lip to vertical through posterior nostril; slightly convex from that point to tip of supraoccipital spine. Dorsal profile of body convex along predorsal region, straight along dorsal-fin base, straight or slightly convex from terminus of dorsal-fin base to adipose-fin origin, and concave from the latter point to origin of dorsal procurrent caudal-fin rays. Ventral profile of head and body convex from tip of lower lip to pelvic-fin origin, concave from that point to anal-fin origin, straight along anal-fin base, and concave from that point to origin of ventral procurrent caudal-fin rays.

Jaws equal, mouth terminal. Premaxillary teeth in two distinct rows (fig. 3). Outer row with 3(3), 4*(26) or 5(1) tricuspid teeth. Inner row with 5*(25) tri- to pentacuspid teeth. Posterior tip of maxilla at vertical through posterior portion of second infraorbital. Maxilla with 2(10), 3(19), or 4(1) tri- to pentacuspid teeth. Dentary with 4*(30) larger pentacuspid teeth followed by a series of 9–13 diminute conical teeth (2). Central median cusp in all teeth longer than lateral cusps. Branchiostegal rays 4(2). First gill arch with 1(2) rakers on hypobranchial, 9(2) rakers on ceratobranchial, 1(2) rakers on intermediate cartilage, and 6(2) rakers on epibranchial.

Scales cycloid, with 7–9 radii from focus to anterior border, and circulii posteriorly. Lateral line completely pored (24), with 31(8), 32(7), or 33*(9) perforated scales on longitudinal series or incomplete (1) with 12 perforated scales and total of 31 scales on longitudinal series. Two specimens with lateral line completely pored with scales of lateral line approximately at vertical through the middle of anal fin with small, poorly developed tube. Longitudinal scale rows between dorsal-fin origin and lateral line 5*(30). Longitudinal scale rows between lateral line and pelvic-fin origin 3(13) or 4*(17). Scales along middorsal line between posterior tip of supraoccipital process and dorsal-fin origin 9(10), 10*(19) or 11(1). Horizontal scale rows around caudal peduncle 14*(30). Base of anteriormost anal-fin rays covered by a series of 4 to 6 scales. Proximal half of caudal-fin lobes covered by small scales.

Supraneurals 5(2). Dorsal-fin rays ii*(30), 9*(30). First dorsal-fin pterygiophore inserted posterior to neural spine of 9th(3) vertebra. Base of last dorsal-fin ray slightly anterior to vertical through base of first branched analfin ray. Pectoral-fin rays i*(30), 10(5), 11(16) or 12*(9). Pelvic-fin rays i*(30), 7*(29) or 8(1). Adipose fin present. Anal-fin falcate, with iv(1) or v(1), 15(3), 16(10), 17*(15), or 18(2) rays. First anal-fin pterygiophore inserted posterior to haemal spine of 17th(2) vertebra. Principal caudal-fin rays i,9,8,i*(30). Caudal fin forked, lobes somewhat pointed, of similar size. Dorsal procurrent caudal-fin rays 11(1); ventral procurrent caudal-fin rays 9(2). Total vertebrae 32(2): precaudal vertebrae 15(2) and caudal vertebrae 17(2).

Color in alcohol. Overall ground coloration of head and body tan ( Fig. 1 ). Dorsal portion of head and body dark. Concentration of dark chromatophores at upper and lower jaws. Infraorbitals with scattered dark pigmentation, mainly on 5th and 6th infraorbitals. Overall body with scattered dark chromatophores gradually fading ventrally. Humeral blotch roughly rectangular, vertically oriented, overlying three or four scales vertically, including the lateral line scale, and one scale horizontally. Humeral blotch evenly pigmented, with approximately the same width along its vertical length. Reticulated pattern on body formed by concentration of dark chromatophores at the posterior margin of scales, more conspicuous in dorsalmost longitudinal scale series. Six to seven longitudinal series of scales on body with dots formed by the concentration of dark chromatophores either beneath the posterior portion of the scale or over the base of the subsequent scale. Longitudinal line formed by subjacent dark pigmentation along horizontal septum starting approximately at vertical through dorsal-fin origin and extending onto caudal peduncle. Vertical light area formed by low concentration of dark chromatophores anterior to the caudal-peduncle spot. Round caudal-peduncle spot restricted to the posterior portion of the caudal peduncle and to the base of the caudal-fin rays. Pectoral and pelvic fins with dark chromatophores scattered along edge of lepidotrichia. Dorsal and anal fins with concentration of dark chromatophores along interradial membranes, higher concentration at distal portion. Adipose-fin base with scattered dark chromatophores. Caudalfin rays with scattered dark chromatophores at interradial membranes and along the edge of lepidotrichia, more concentrated in outermost rays.

Color in life. Dark pigmentation pattern of coloration in life similar to that described for preserved specimens. Overall body coloration silver to pale beige ( Fig. 2 ). Top of head green. Dorsal portion of iris orange and ventral portion blue. Conspicuous bright green stripe crossing the eye and extending posteriorly on body, ending at caudal peduncle. All fins yellowish. Anterior portion of dorsal, anal, and base of outermost principal caudal-fin rays light yellow to orange.

Sexual dimorphism. No sexually dimorphic feature was observed in the examined specimens. Geographic distribution. Moenkhausia lineomaculata is known from the rio Juruena basin, upper rio Tapajós basin, Mato Grosso State, Brazil ( Fig. 4 ).

Etymology. The specific name “ lineomaculata ” comes from the Latin lineo meaning line, and maculata meaning spotted, in allusion to the longitudinal series of aligned spots characteristic of the new species. An adjective.

Figures

FIGURE 1. MZUSP 117108, 67.9 mm SL, holotype of Moenkhausia lineomaculata, Brazil, Mato Grosso State, Campos de Júlio, rio Juruena, upper rio Tapajós basin.

FIGURE 2. Not preserved live specimen of Moenkhausia lineomaculata, Brazil, Mato Grosso State, Sapezal, rio Juruena, upper rio Tapajós basin. Part of the lower lobe of the caudal fin is missing.

FIGURE 3. Upper and lower jaws of Moenkhausia lineomaculata, paratype, MZUSP 106327, 34.9 mm SL, medial view of right side. Scale bar: 1 mm.

FIGURE 4. Distribution map of Moenkhausia lineomaculata (yellow dots) in the upper rio Juruena basin, Brazil. White star symbol represents the type locality. Each symbol may represent more than one collection event.

Tables

TABLE 1. Morphometric data of Moenkhausia lineomaculata. Range includes holotype, n = 30, SD = Standard deviation.

	Holotype Paratypes	Mean	SD
Standard length (mm)	67.8 21.6–67.8	32.5
Percentages of SL
Depth at dorsal-fin origin	36.7 31.5–36.9	34.1	1.7
Snout to dorsal-fin origin	55.1 52.2–57.2	55.0	1.3
Snout to pectoral-fin origin	27.2 27.2–32.9	30.9	1.4
Snout to pelvic-fin origin	49.9 49.9–55.2	52.2	1.5
Snout to anal-fin origin	68.2 66.3–71.4	68.7	1.3
Caudal-peduncle depth	12.8 11.3–13.6	12.3	0.7
Caudal-peduncle length	8.7 8.7–13.1	11.5	1.0
Pectoral-fin length	20.0 18.9–24.7	22.5	1.6
Pelvic-fin length	16.3 14.2–19.4	17.6	1.1
Pelvic-fin origin to anal-fin origin	20.4 16.2–20.5	18.5	1.1
Dorsal-fin length	24.3 24.3–33.7	29.7	2.1
Dorsal-fin base length	14.0 13.3–17.3	14.7	0.9
Anal-fin length	18.7 18.1–25.6	22.7	1.8
Anal-fin base length	24.0 19.8–24.9	23.2	1.1
Eye to dorsal-fin origin	41.3 36.2–41.3	38.4	1.1
Dorsal-fin origin to caudal-fin base	49.1 44.5–51.7	47.2	1.6
Head depth	28.7 27.3–32.5	29.9	1.2
Head length	26.6 26.6–33.3	30.4	1.6
Percentages of HL
Horizontal eye diameter	35.3 31.3–43.9	39.5	2.8
Snout length	29.1 19.3–29.7	24.4	2.2
Interorbital width	43.1 30.0–43.1	35.9	2.3
Upper jaw length	52.4 44.4–52.8	48.7	2.2