Taxonomic study of Moenkhausia cotinho Eigenmann, 1908 and Hemigrammus newboldi (Fernández-Yépez, 1949) with the description of two new species of Moenkhausia (Teleostei: Characiformes: Characidae) Mathubara, Kleber Toledo-Piza, Mônica Zootaxa 2020 2020-09-14 4852 1 1 40 Mathubara & Toledo-Piza, 2020 Mathubara & Toledo-Piza 2020 [151,423,438,465] Actinopterygii Characidae Moenkhausia Animalia Characiformes 24 25 Chordata species pirahan sp. nov.  ( Figs. 13–15)  urn:lsid:zoobank.org:pub: 301C1BCC-51F1-43E0-9774-85DC28741E10     Holotype: MZUSP 125777(1, 62.5 mmSL), Brasil, Rondônia, Igarapé Traíra, Transamazônicahighway, 40 Kmfrom the ferryboat of Humaitá, to Apuí, Humaitá, 7°35’31”S 62°44’45”W, W.M. Ohara,  15 Aug 2015.    Paratypes: MZUSP 125778(4, 62– 65.8 mmSL);  ZUEC 17237(2, 62.4–64.6 mmSL);  UFRO 15783(2, 59.1– 60 mmSL), same data as holotype.  UFRO 23068(1, 49.9 mmSL), Igarapé Cachoeira, above Aripuanã, 6°24’45”S 60°21’26”W, Fernandes, Talles,  19 Mar 2013.   Non-typematerial:   Brazil: Amazonas: rio Madeirabasin: UFRO-I 23068(1-1, 49.4 mmSL), Igarapé Cachoeira, upstream of rio Aripuanã, Novo Aripuanã, 6°24’45”S 60°21’26”W, T. Fernandes;   Pará: rio Tapajósbasin, MPEG 28777(3-3, 39.8–50.2 mmSL), Jacareacanga, rio Tapajósbasin, Ambiental Concremat,  20 Aug 2013;   Pará, rio Trombetasbasin: INPA 48615(4-4, 46.5–53.3 mmSL), Lagoa Sapucuruá, mouth of Igarapé Araticum, Oriximiná, G.M. dos Santos,  21 Jul 2015;  INPA 50033(8-8, 30.9–46.8 mmSL), rio Trombetas, igarapé of Tental, left margin, Oriximiná, 1°25’51”S 56°45’52”W, I.M. Soares& A. Akama,  18 Nov 2013;  INPA 50082(1-1, 48.4 mmSL), Oriximiná, rio Trombetas, igarapé Terra Preta, right margin, 7°45’45”S 58°49’0”W, I.M. Soares& A. Akama,  19 Nov 2013;  INPA 34406(5-5, 37.6–47.6), rio Trombetas, Oriximiná, 1°28’1”S 56°20’5”W, E. Ferreira& J. Zuanon,  25 Nov 2005;  MPEG 14598(7-7, 42.5–55.5 mmSL), rio Saracá(Porto Trombetas), Oriximiná, W. Wosiacki,  18 Oct 2007;  MPEG 15430(1-1, 45.3 mmSL), Porto Cikel, rio Nhamundá, Faro, 1°42’48”S 57°12’48”W, L.F. Montag,  27 Jan 2008;  MPEG 23687(1-1, 38.3 mmSL), Alenquer, 1°34’47”S 55°0’36”W, J, Ready,  20 Jun 2010;  MPEG 27968(2-2, 50.3–50.6 mmSL), Vila de São Martins, Jacareacanga, 6°8’13”S 57°40’23”W,  T. Begot,  30 Mar 2013;  MPEG 28055(1-1, 45.4 mmSL), rio Saracá, 1°48’9”S 56°16’33”W, W. Wosiacki,  20 Oct 2007.   Diagnosis.  Moenkhausia pirahanis distinguished from all congeners, except  M. australis,  M. cosmops,  M. cotinho,  M. diktyota,  M. forestii,  M. lineomaculata,  M. oligolepis,  M. parecis,  M. pyrophthalma,  M. sanctaefilomenae, and  M. uirapuruby the presence of a reticulate body color pattern resulting from the presence of chromatophores forming a dark rim and delineating the posterior margin of the scales ( Fig. 4B) and the presence of a dark blotch on the base of the caudal fin (vs absence of both reticulate color pattern( Fig. 4C–D) and the dark blotch on the caudal-fin base). It is distinguished from all the above-mentioned species by the presence of three interrupted stripes formed by light spots on the central portion of the scales of the three dorsalmost longitudinal series on the body (vs. interrupted stripes absent). It is further distinguished from  M. cotinhoby having in life, an orange to reddish longitudinal stripe on body just below the ventralmost interrupted dark stripe ( Figs. 13–14); (vs. orange to reddish stripe absent).   Description.Morphometric data presented in Table 3. Body compressed, moderately elongate. Largest specimen examined 66.5 mmSL; greatest body depth slightly anterior to dorsal-fin origin. Dorsal profile of head convex from snout tip to vertical through posterior nostril; slightly convex from that point to tip of supraoccipital spine. Dorsal profile of body convex along predorsal region; straight and posteriorly inclined along dorsal-fin base; posteriorly inclined to moderately convex to adipose fin; concave from along dorsal margin of caudal peduncle. Ventral profile of head and body convex from anterior tip of dentary to anal-fin origin; posterodorsally inclined from latter point to base of last anal-fin ray; concave along ventral margin of caudal peduncle. Mouth terminal, jaws equal. Posterior portion of maxilla extending beyond vertical through middle of orbit. Premaxillary teeth in two rows; outer row with 3(2), 4*(20) tricuspid teeth inner row 5*(22) tri- to pentacupid teeth. Dentary with 5 (22) large pentacuspid teeth followed by a series of 10(1) or 11(2) diminutive tricuspid teeth ( Fig. 16). Central median cusp of all teeth longer than lateral cusps ( Fig. 16). Branchiostegal rays 4(3). First gill arch with 2(3) rakers on hypobranchial, 9(2) rakers on ceratobranchial, 1(2) on intermediate cartilage, and 7(2) rakers on epibranchial.   TABLE 3. Morphometric data of  Moenkhausia pirahan. N= Number of specimens, H= holotype (MZUSP 125777), SD= standard deviation. Standard length in mm.    N H Range Mean SD  Standard length 43 62.5 30.9–66.5 – –   Percents of standard length  Depth at dorsal-fin origin 43 32.8 28.9–34.8 32.0 1.5  Snout to dorsal-fin origin 42 52.1 50.0–55.6 52.7 1.3  Snout to pectoral-fin origin 42 26.2 26.2–32.6 28.3 1.3  Snout to pelvic-fin origin 42 49.3 47.4–53.7 50.4 1.1  Snout to anal-fin origin 42 70.2 65.7–74.1 70.5 1.4  Eye to dorsal-fin origin 41 37.9 33.3–40.7 38.1 1.2  Dorsal-fin origin to caudal-fin base 42 48.3 46.4–52.4 49.1 1.4  Dorsal-fin length 43 24.6 23.9–28.7 26.4 1.3  Dorsal-fin base length 43 12.3 11.3–16.0 13.2 1.0  Pectoral-fin length 42 19.0 19–29.1 22.6 2.0  Pelvic-fin length 42 16.8 15.9–20.8 18.0 0.9  Anal-fin length 43 19.2 23.4–28.8 26.1 1.3  Anal-fin base length 42 21.7 19.7–25.0 22.0 1.0  Caudal-peduncle depth 42 11.5 10.0–12.5 11.6 0.4  Caudal-peduncle length 40 10.0 8.9–12.3 10.4 0.9  Head Length 43 25.7 24.9–29.7 26.7 1.0   Percents of head length  Snout length 41 23.7 22.8–29.1 25.9 1.3  Horizontal eye diameter 40 40.0 36.6– 46.7 41.7 2.3  Interorbital width 42 40.0 32.7–41.9 36.8 2.0  Upper jaw length 43 38.7 34.8–48.2 42.3 3.2 Supraneurals 4(1) or 5(2), obliquely oriented. First supraneural anterior to neural spine of 5 thvertebra, fourth supraneural between neural spines of 7 thand 8 th(1) or 8 thand 9 th(2) vertebra. Origin of dorsal fin at approximately half of SL; first pterygiophore of dorsal fin anterior to neural spine of 9 thvertebra. Dorsal-fin rays ii, 9 (43); supernumerary dorsal-fin rays 1(2). Origin of anal fin near half of SL, first pterygiophore of anal fin anterior to haemal spine of 16 th(1) or 17 th(22) vertebra. Anal fin falcate; anal-fin rays iv, 15(1), 16(12), 17*(16), 18(11), 19(2), or 21(1). Pectoral fin i, 12(2), 13(16), 14*(18), 15(6), or 16(1), longest pectoral-fin ray not extending beyond the base of distal pelvic fin ray. Pelvic-fin origin anterior to vertical through dorsal-fin origin. Pelvic-fin rays i, 7*(43), longest ray of pelvic fin reaching urogenital opening. Caudal fin forked, principal caudal-fin rays on dorsal lobe i, 9(3), and on ventral lobe i, 8(1), 9(2); dorsal procurrent caudal-fin rays 9(3), ventral procurrent caudal-in rays 8(3). Adipose fin anterior to vertical through base of posteriormost anal-fin ray. Scales cycloid, with five (3) radiimoderately diverging posteriorly from focus to posterior field of scale; conspicuous circuliipresent dorsally and ventrally of radial field and continuous anteriorly on embedded portion of scale ( Fig. 7C). Axillary scale on pectoral and pelvic fins. Proximal one third of caudal fin lobes covered by small scales. Lateral line complete; lateral-line tube present on caudal fin posterior to last perforated scale. Pored lateral-line scales 29(1), 30(10), 31*(24), 32(4), or 33(2). Predorsal scales 9(7), 10*(32), or 11(1). Longitudinal scale rows between dorsal-fin origin and lateral line 5*(42), longitudinal scale rows between lateral line and pelvic-fin origin 3*(41). Middorsal scales between base of posteriormost dorsal-fin ray and adipose-fin 8(10), 9(29), 10(1). Circumpeduncular scales 12(2), 13(14), 14*(14), or 15(5). Total vertebrae 25(3): precaudal vertebrae 12(3), caudal vertebrae 13(3).   FIGURE 16.Premaxilla, maxilla and dentary of  Moenkhausia pirahan, UFRO15783, 59.1 mm SL. Right side, medial view. Scale bar = 1 mm.  Color in alcohol.Overall ground coloration of head and body yellowish. Dorsal portion of head darker than ventral. Tips of upper and lower jaws dark. Infraorbitals with scattered dark pigmentation. Predorsal and preadipose scales dark, forming a longitudinal line along the dorsal midline of body. Posterior margin of scales delineated by chromatophores forming a dark rim resulting in a reticulate pattern on body, more evident on region dorsal of lateral line ( Fig. 4B). Scales of longitudinal rows on body dorsal to lateral line with dark spots on posterior edge; spot on scales sometimes extending to anterior portion of adjacent scale. Central area of scales of three dorsalmost longitudinal series with lighter spots forming three interrupted stripes. Humeral blotch vertically elongate, with dorsal portion covering horizontally approximately three scales and distinctly darker than ventral portion. Humeral blotch extending vertically on scales of four longitudinal rows. A longitudinal stripe extending from humeral blotch to caudal peduncle; stripe silver on specimens that retain guanine on body, dark on other specimens. A large blotch on base of caudal fin not reaching tips of median caudal-fin rays. Blotch almost rounded with scattered chromatophores on dorsalmost and ventralmost principal caudal-fin rays. Middle portion of caudal-fin rays whitish and tips hyaline. Dorsal, anal, adipose, pectoral and pelvic fins mostly hyaline with few scattered chromatophores ( Fig. 15).  Color in life.Based on photographs of specimens just after collection. Dorsal portion of head and body olivaceous, ventral portion silvery. Dark pigmentation pattern of coloration in life similar to that described for preserved specimens except that reticulate pattern is less marked than in preserved specimens. An orange to reddish longitudinal stripe on body just below ventralmost interrupted dark stripe. Dorsal region of eyes reddish. A silvery longitudinal stripe extending from humeral spot to caudal peduncle. Middle portion of caudal fin rays, anterior rays of anal fin, dorsal, adipose, pelvic and pectoral fin rays yellow to orange ( Figs. 13–14).   Distribution.  Moenkhausia pirahanoccurs in the basins of rio Madeira, rio Trombetas and rio Tapajós, in four of the regions proposed by Dagosta & de Pinna (2017)for the Amazon and neighboring regions (7. Teles Pires, 14. Middle-Lower Madeira, 15. Madeira Shield Tributaries, 26. Trombetas ( Fig. 17).   Etymology:The specific epithet,  pirahan, is in honor to the Pirahã tribe that live close to typelocality of this species, in the county of Humaitá, Amazonas state, Brazil. 3028259400 2015-08-15 MZUSP W. M. Ohara Brazil Igarape Traira -7.5919447 Km 21 -62.745834 Transamazonica 24 25 MZUSP 125777 1 Rondonia holotype 3028259328 [199,753,648,675] MZUSP 24 25 MZUSP 125778 1 paratype 3028259366 [763,1169,648,675] ZUEC 24 25 ZUEC 17237 1 paratype 3028259351 2015-08-15 UFRO W. M. Ohara Brazil Igarape Traira -7.5919447 Km 21 -62.745834 Transamazonica 24 25 UFRO 15783 1 Rondonia paratype 3028259318 2013-03-19 UFRO Brazil -6.4125 21 -60.35722 24 25 UFRO 23068 1 Rondonia paratype 3028259397 T Brazil Igarape Cachoeira -6.4125 Amazonas 21 -60.35722 rio Aripuana 24 25 UFRO-I 23068 1 Amazonas 3028259358 2013-08-20 T Jacareacanga & Ambiental Concremat Brazil Fernandes 24 25 MPEG 28777 1 Para 3028259305 2015-07-21 INPA G. M. dos Santos Brazil Lagoa Sapucurua 24 25 INPA 48615 1 Para, rio Trombetas 3028259322 2013-11-18 INPA I. M. Soares & A. Akama Brazil rio Trombetas -1.4308333 Oriximina 21 -56.764446 Tental 24 25 INPA 50033 1 Para, rio Trombetas 3028259343 2013-11-19 INPA I. M. Soares & A. Akama Brazil Oriximina -7.7625 Terra Preta 21 -58.816666 rio Trombetas 24 25 INPA 50082 1 Para, rio Trombetas 3028259385 2005-11-25 INPA E. Ferreira & J. Zuanon Brazil -1.4669445 Oriximina 21 -56.33472 rio Trombetas 24 25 INPA 34406 1 Para, rio Trombetas 3028259336 2007-10-18 MPEG Oriximina, W & Wosiacki Brazil rio Saraca 24 25 MPEG 14598 1 Para, rio Trombetas 3028259337 2008-01-27 MPEG L. F. Montag Brazil Porto Cikel -1.7133334 Faro 21 -57.213333 rio Nhamunda 24 25 MPEG 15430 1 Para, rio Trombetas 3028259301 [265,1272,1116,1143] 2010-06-20 MPEG Ready Brazil -1.5797222 Alenquer 21 -55.01 24 25 MPEG 23687 1 Para, rio Trombetas 3028259367 MPEG Brazil -6.1369443 Jacareacanga 21 -57.673058 Vila de Sao Martins 24 25 MPEG 27968 1 Para, rio Trombetas 3028259361 [1093,1347,1152,1179] 2013-03-30 T Brazil Begot 24 25 1 Para, rio Trombetas 3028259339 2007-10-20 MPEG W. Wosiacki Brazil -1.8025 rio Saraca 21 -56.275833 24 25 MPEG 28055 1 Para, rio Trombetas