Mylossoma aureum
Creators: name: Mateussi, Nadayca T. B.
name: Oliveira, Claudio
name: Pavanelli, Carla S.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Characiformes
Serrasalmidae
Mylossoma
Mylossoma aureum

description: Mylossoma aureum (Agassiz, 1829)
(Figs 10–15, Table 3)
Myletes aureus Agassiz, in Spix & Agassiz, 1829: 74, plate XXI [original description; type-locality: "Brasiliae aequatorialis fluviis"; cited as Tetragonopterus aureus in the plate].— Kottelat, 1984: 146 [designation of potential syntypes].— Kottelat, 1988: 84 [designation of potential syntypes; details on autorship].
Myletes herniarius Cope, 1872: 268 [original description; type-locality: "Ambyiacu"].— Böhlke, 1984: 48 [type-material listed].
Starksina herniarius.— Fowler, 1907: 476 [redescription of type specimens; lectotype designation].
Mylosoma [sic] aureum.— Eigenmann, 1910: 444 [listed, catalog of South American freshwater fishes].
Mylosoma aureus.— Eigenmann, 1915: 265 [redescription].
Mylossoma aureum.— Norman, 1929: 813 [brief description].— Eigenmann & Allen, 1942: 249 [description, Peru].— Géry, 1976: 48 [listed].— Ortega & Vari, 1986: 9 [listed, Peru].— Machado-Allison & Castillo, 1992: 17 [morphology; allometry; Orinoco basin, Venezuela].— Taphorn, 1992: 477 [description; río Apure basin, Venezuela].— Machado-Allison & Fink, 1996: 78 [Rio Orinoco basin, Venezuela; brief description]— Oliveira & Araújo-Lima, 1998 [larvae habits and distribution].— Jégu, 2003: 187 [listed].— Ota et al., 2013: 27 [rio Madeira basin, Brazil; brief description, photo].
Mylossoma ventriosa Norman, 1929: 815 [original description, type-locality: "Solimões, R. Amazon"].
Mylossoma aureus.— Nelson, 1961: 608 [swim bladder morphology].
Diagnosis: Mylossoma aureum differs from all congeners by presenting the last abdominal spine clearly separated from the anal-fin origin (vs. last abdominal spine reaching the anal-fin origin or almost) and 38–39 vertebrae (vs. 35 to 37).
Description: Morphometric data presented in Table 3. Body deep, compressed laterally. Dorsal profile concave at posterior region of head and convex between head and dorsal fin. Ventral profile convex; slightly concave at isthmus and strongly convex from this point to end of anal fin. Highest body depth on vertical line passing through dorsal- and pelvic-fins origins. Caudal peduncle deeper than longer.
Small head. Eyes lateral at middle of head; upper margin of eyes below longitudinal axis of lateral-line origin. Frontal and parietal fontanel broadly expanded laterally. Snout short and rounded on lateral view. Nostrils dorsolateraly positioned, above longitudinal axis through upper margin of eye.
Mouth terminal to slightly upturned, at same level of orbits. Premaxilla projected forward, with inner premaxillary row over or surpassing dentary teeth (Fig. 12). Premaxillary teeth molariform with robust base; outer portion of anteriormost three teeth of outer row and posterior portion of remaining teeth pointed. Inner premaxillary row with two teeth, separated from outer row. Outer premaxillary row with five teeth. Dentary with four (rarely five) tricuspid, robust, molariform teeth; symphyseal dentary teeth present, with robust base and large conical cusp, behind main row (Fig. 2). Maxilla edentulous.
First gill arch with elongated and conical gill rakers; epibranchial gill-rakers 10(19), 11(15), 12(21) or 13(1); one (45) gill raker at cartilage between epi- and ceratobranchial; ceratobranchial gill-rakers 12(2), 13(3), 14(11), 15(24), 16(10) or 17(5).
Body completely covered by small cycloid scales. Accessory scales covering intersections of major scales, mainly at anterior portion of body. Lateral line complete, with 81(1), 82(3), 84(3), 85(2), 86(3), 87(5), 88(2), 89(4), 90(8), 91(9), 92(6), 93(7), 94(6), 95(7), 96(7), 97(3), 98(2), 99(4), 100(2), 102(1) or 104(1) perforated scales, extending into caudal fin. Scales above lateral line 42(1), 44(2), 45(1), 46(3), 48(1), 49(1), 50(4), 51(3), 52(5), 54(4), 55(4), 56(9), 57(6), 58(3), 59(3), 64(1) or 68(1). Scales below lateral line 38(1), 39(1), 40(1), 42(2), 43(3), 44(1), 45(8), 47(5), 48(2), 49(4), 50(2), 51(2), 52(1), 53(4) or 56(2). Circumpeduncular scales 28(8), 30(15), 31(2), 32(21), 33(3), 34(11), 35(1) or 36(2). Ventral keel with well-developed spines forming high serra. Prepelvic spines 25(2), 26(2), 27(4), 28(13), 29(19), 30(24), 31(15), 32(10), 33(10), 34(2) or 35(1). Postpelvic spines 10(6), 11(17), 12(23), 13(25), 14(16) or 15(4); anal spines small, maximum 3, clearly separated from anal-fin origin, discernible only if dissected (Fig. 12).
Dorsal fin not preceded by spine, its origin equidistant from tip of snout and end of hypural plate. First dorsalfin ray much shorter than second ray; in some specimens covered by skin, in such cases discernible only if dissected or x-rayed (Fig. 12). Branched dorsal-fin rays gradually decreasing in size; dorsal-fin rays 12(1), 14(14), 15(62) or 16(27). Adipose fin short, entirely covered by small scales. Pectoral fin falcate, with i(88) + 12(1), 13(7), 14(34), 15(38), 16(22) or 17(3) rays. Pelvic fin small, with i + 6(89) branched rays. Anal fin long, with convex edge, median and posterior rays longer than anterior ones, not lobed; sheath of scales covering at least two-thirds of anal-fin length; anal-fin rays 28(7), 29(13), 30(21), 31(39), 32(18), 33(5), 34(2) or 35(1). Caudal fin bifurcated, lobes of similar size, with 16(6), 17(69), 18(6), 19(2) or 21(1) rays. Vertebrae 38(9) or 39(2). Supraneurals 4(11).
Color in alcohol. General body color silvery-brownish or silvery-yellowish, darker dorsally (Fig. 11). Fins hyaline with yellow hue; caudal-fin and anal-fin bases, and distal margin of anal fin slightly dark. Dark to brown blotch on opercle usually absent or inconspicuous. Juvenile specimens with vertical, faded brown bands on flanks; a rounded brown ocellar blotch below dorsal fin, small and inconspicuous, sometimes absent (Fig. 13).
Color in life. General body color silvery; darker dorsally; orange or reddish tint on anterior portion of abdominal region, head and around the eyes. Black or brownish blotch on opercle usually absent, if present, inconspicuous. Anal fin with orange or yellow tint, sometimes with a dark band along distal margin; dorsal, pectoral and pelvic fins with orange base and posterior portion hyaline; caudal fin hyaline. Juveniles with vertical dark, relatively inconspicuous stripes along flanks (Fig. 14, 15).
Geographic distribution. Mylossoma aureum is widely distributed across the Amazon and Orinoco river basins (Fig. 3).
Ecological notes. Mylossoma aureum is a highly fecund, fast growing species with high mortality rates in early life stages (Lima & Araújo-Lima, 2004). The species is considered an omnivore with high tendency to herbivory, feeding mainly on vegetal matter and invertebrates. Mylossoma aureum undertakes reproductive migrations, and the spawning occurs during the flood season, mainly in white waters rivers and associated wetlands (Santos et al., 2006). Mylossoma aureum has moderate importance in commercial fisheries (Santos et al., 2006).
Molecular data. DNA barcoding showed a variation of 0.084 to 0.091 between examined samples of M. aureum and the remaining analyzed species, with M. albiscopum (identified as M. duriventre group 5) being the closest related species (Mateussi et al., 2016).
Remarks. Agassiz (in Spix & Agassiz, 1829) mentioned that three specimens were examined for the description of Myletes aureus: " In Museo Monacensi specimina tria in spiritu vini servantur ". Kottelat (1984, 1988) designated the lots MHNN 787 and MHNN 788 as possible syntypes for Myletes aureus. However, the examination of pictures of these specimens revealed that specimen MHNN 787 belongs actually to Mylossoma albiscopum. Thus, we designate the specimen MHNN 788-A as lectotype of M. aureum and the specimen MHNN 788-B as a paralectotype.
Taphorn (1992), Machado-Allison & Castillo (1992), and Machado-Allison & Fink (1995) presented morphological data from Mylossoma aureum specimens from the Orinoco basin. We unfortunately were unable to examine specimens of Mylossoma aureum from the Orinoco basin, but the data presented by these authors indicates that this population is clearly conspecific with the population occurring at the Amazon basin.
Material examined. Type material. MHNN 788-A, 1, Brazilian equatorial rivers. Lectotype (by present designation) of Myletes aureus. MHNN 788-B, 1, Brazilian equatorial rivers. Paralectotype of Myletes aureus. ANSP 8025, 1 (rd), río Ambyiacu, Peru. Lectotype of Myletes herniarius (designated by Fowler, 1907). BMNH 1923.10.28.263, rio Solimões. Holotype of Mylossoma ventriosa. Non-type material. Brazil. Rio Amazonas basin. Amazonas: INPA 20264, 3, 87.0– 88.5 mm SL, Manaus, Canal Xiborena, 03°12'30"S 59°59'00"W, 14 Apr 2000, C. Cox-Fernandes et al. INPA 20287, 4, 15.7–55.0 mm SL, Manaus, Canal Xiborena, 03°12'30"S 59°59'00"W, 15 Mar 2000, L. Rajys et al.. INPA 20332, 1, 48.6mm SL, Iraduba, lago Pirapora at Catalão lakes complex, 03°10'09''S 59°54'43''W, 13 Jul 2000, L. R. Py-Daniel & J. Zuanon. INPA 20337, 1, 65.8 mm SL, lago do Padre, 03°25'31"S 60°57'56"W, Jul 2000, L. R. Py-Daniel et al. INPA 29063, 1, 103.4 mm SL, Carauarí, RDS Uacari, rio Juruá, 05°56'26"S 67°48'21"W, 24 Nov 2007, R. G. Frederico & L. J. Queiroz. INPA 29699, 1, 99.9 mm SL, Carauarí, RDS Uacarí, lago da Terra, rio Juruá tributary, 05°30'34"S 67°27'58"W, 28 Nov 2007, R. G. Frederico & L. J. Queiroz. INPA 29749, 1, 93.9 mm SL, Carauarí, RDS Uacari, rio Juruá, 05°56'26"S 67°48'21"W, 22 Nov 2007, R. G. Frederico & L. J. Queiroz. INPA 33885, 1, 98.7 mm SL, Nhamundá, rio Nhamundá, 02°13'51"S 56°46'23", 21 Sep 2011, R. Leitão & H. Lazzarotto. INPA 39641, 3, 9.2–12.16 mm SL, Itacoatiara, igarapé do Centenário, 03°08'25"S 58°27'25"W, 16 Apr 2011, E. L. H. Takahashi. INPA 43781, 1 (sk), Iranduba, lago Pirapora, 03°10'09"S 59°54'43"W, 0 1 Jul 2014, S. A. Amadio. INPA 46096, 1, 68.2 mm SL, Carauarí, RDS Uacari, rio Juruá, 05°56'26"S 67°48'21"W. MPEG 1542, 1, 74.7 mm SL, Japurá, lago Amanã, rio Japurá, 02°35'48"S 64°39'46"W. Pará: MCP 20962, 2, 71.4–74.2 mm SL, Alenquer, ilha de São Miguel, rio Amazonas, 01°56'S 54°44'W, 26 Nov 1997, R. B. Oliveira. MCP 21042, 1 (rd), 107.8 mm SL, Alenquer, ilha de São Miguel, rio Amazonas, 01°56'S 54°44'W, 26 Nov 1997, R. B. Oliveira. MPEG 5225, 1, 110.0 mm SL, Oriximiná, rio Trombetas, 01°43'10"S 55°55'22"W. MPEG 14102, 1, 82.6 mm SL, Juruti, rio Amazonas, 02°11'23.7"S 56°08'04"W. Rondônia: UFRO-ICT 13555, 1, 13.7 mm SL, Pimenteiras do Oeste, Porto Surpresa, rio Guaporé, 11°53'13"S 65°01'16.1"W, 11 Jan 2012. Rio Madeira basin. Amazonas: INPA 24346, 11, 106.4– 144.8 mm SL, comunidade Itapinima, rio Madeira, 05°24'37"S 60°43'16"W, 22 Sep 2004. INPA 24347, 2, 120.6– 125.6 mm SL, comunidade Itapinima, rio Madeira, 05°24'37"S 60°43'16"W, 21 Sep 2004, L. R. Py-Daniel et al.. INPA 24349, 1, 118.8 mm SL, comunidade Vencedor, lago do Acará, rio Madeira, 03°38'9.69"S 62°42'31.95"W, 22 Sep 2004, L. R.
Py-Daniel et al. UFRO-ICT 1137, 1 (rd), 132.8 mm SL, Humaitá, lago do Puruzinho, rio Madeira, 07°22'21.3"S 63°03'10.1"W, 0 2 Dec 2008, L. J. Queiroz. UFRO-ICT 1259, 1 (rd), 155.1 mm SL, Novo Aripuanã, rio Aripuanã, rio Madeira, 05°08'30.5"S 60°24'03.3"W, 0 5 Dec 2008, A. Cella-Ribeiro. Rondônia: INPA 3791, 5 (4), 153.6– 176.5 mm SL, rio Machado, 08°20'18"S 62°42'33"W, 0 1 Sep 1977, M. Goulding. UFRO-ICT4776, 1 (rd), 116.4 mm SL, Nova Olinda do Norte, lago Sampaio, rio Madeira basin, 03°49'06"S 59°05'27"W, 30 Jan 2012, A. Cella- Ribeiro. UFRO-ICT 7500, 2, 118.1– 120.8 mm SL, Porto Velho, rio Machado, 08°20'18"S 62°42'33"W, 0 1 Dec 2011. UFRO-ICT 9278, 2 (rd), 109.2–112.2 mm SL, Porto Velho, cachoeira Santo Antônio, rio Madeira, 08°47'32"S 65°56'05"W, 24 Oct 2010, W. M. Ohara. UFRO-ICT 13307, 1, 132.0 mm SL, Porto Velho, cachoeira Santo Antônio, rio Madeira, 08°48'30"S 63°36'53"W, 13 Dec 2008, Equipe SET. UFRO-ICT 19346, 1, 112.0 mm SL, Porto Velho, Igarapé Jatuarana, rio Madeira, 08°45'54''S 64°02'39''W, 19 Feb 2013, E. Façanha. Rio Negro. Amazonas: LBP 21832, 2, 103.7– 109.4 mm SL, Manaus, Catalão, rio Negro, 03°12'00''S 59°57'39''W, 12 May 2016, N.T.B. Mateussi et al. Rio Purus basin. Acre: MCP 28927, 2 (1), 123.6 mm SL, Sena Madureira, rio Purus (bought at the Sena Madureira fish market), 09°08'59"S 68°35'00"W, 0 8 Aug 2001. Amazonas: INPA 16776, 1, 124.6 mm SL, beach at Reserva Biológica do Abufari, rio Purus, c. 05°32'5"S 63°04'44"W, 0 9 Dec 2000, L. R. Py- Daniel & M. Garcia. INPA 18533, 2, 60.1–61.2 mm SL, Reserva Biológica do Abufari, rio Purus, 05°32'5"S 63°04'44"W, 0 8 Dec 2000, L. R. Py-Daniel et al. INPA 46974, 5 (rd), 86.5–182.3 mm SL, Tapauá, igarapé Castanhalzinho, 04°59'50"S 62°59'38"W, 10 Aug 2012, L. R. Py-Daniel et al. Rio Solimões basin, Amazonas: INPA 11093, 1, 61.6 mm SL, Iranduba, ilha da Marchantaria, rio Solimões, 03°17'05"S 60°11'10"W, 17 Jun 1988, Equipe de Ictiologia do INPA. INPA 18813, 15, 24.0– 55.4 mm SL, Reserva Mamirauá, lago Secretaria (rio Solimões), c. 02°11'32"S 65°42'30"W, 0 1 Mar 2001, W. Crampton. INPA 19533, 1, 77.8 mm SL, Alvarães, rio Solimões, c. 03°46'30"S 65°22'50"W, 29 Jan 2001, W. Crampton. INPA 19535, 2, 57.2–76.4 mm SL, ilha do Içé, rio Solimões, 03°16'36"S 64°41'01"W, 0 1 Jan 2001, W. Crampton. INPA 25758, 1, 99.5 mm SL, Manaus, lago Muratu, rio Solimões, 03°20'51"S 60°12'34"W, 0 1 Jul 2003, M. C. Vega. INPA 25784, 1, 109.2 mm SL, Manaus, lago Muratu, rio Solimões, 03°20'51"S 60°12'34"W, 0 1 Jun 2003, M. C. Vega. INPA 28919, 1, 75.8 mm SL, Carauarí, RDS Uacari, rio Juruá, 05°42'23"S 67°49'17"W, 26 Nov 2007, R. G. Frederico & L. J. Queiroz. INPA 29753, 1, 97.5 mm SL, Carauarí, RDS Uacari, rio Solimões, 05°54'20"S 67°51'59"W, 22 Nov 2008, R. G. Frederico & L. J. Queiroz. INPA 33132, 1, 52.3 mm SL, Tabatinga, rio Solimões, 03°57'32"S 69°20'19"W, 0 2 Sep 2003, J. Zuanon et al.. INPA 33133, 1, 17.4 mm SL, Coari, Ressaca Geral, rio Solimões, 03°51'10"S 63°28'07"W, 13 Sep 2003, L. R. Py-Daniel et al.. INPA 3790, 26 (11), 27.5–71.3 mm SL, Iranduba, ilha da Marchantaria, rio Solimões, 03°17'05"S 60°11'10"W, 20 Mar 1976, Ictiologia INPA. LBP 18401, 1, 95.7 mm SL, Manacapuru, rio Solimões, 03°18'53"S 60°38'58"W, 21 Aug 2013, C. Oliveira et al. LBP 21801, 1, 42.9 mm SL, Tefé, Paraná de Tefé, rio Solimões, 03°21.05'S 64°40.06'W, 19 May 2016, N.T.B. Mateussi et al. LBP 21777, 2, 26.2–33.1 mm SL, Alvarães, Paraná do Icé, rio Solimões, 03°15.49'S 64°42.92'W, 19 May 2016, N.T.B. Mateussi et al. MCP 31679, 2, 103.7– 111.6 mm SL, Alvarães, lago Mamirauá (rio Solimões basin), 03°06'37"S 64°47'45"W, 14 May 1998. MCP 31680, 1, 40.3 mm SL, Tefé, rio Solimões, 03°16'9"S 64°39'09"W, 11 Jan 2001. MCP 31681, 1, 82.4 mm SL, Alvarães, ilha do Içé, rio Solimões, 03°16'36"S 64°41'01" W. Rio Xingu basin, Pará: INPA 40703, 1, 94.2 mm SL, Porto de Moz, rio Xingu, 01°43'54"S 52°15'16"W, 24 Sep 2013, M. Sabaj Perez. Colombia. Rio Amazonas basin, Amazonas: LBP 22515, 6, 49.1–63.0 mm SL, Leticia, Lago Yahuarcaca, rio Amazonas, 04°11'45''S 69°57'20''W, 12 Nov 2016, C. Oliveira & B.F. Melo. Peru. Rio Amazonas basin, Loreto: LBP 22606, 5, 52.4–104.2 mm SL, rio Amazonas, 04°14'04''S 69°57'42''W, 14 Nov 2016, C. Oliveira & B.F. Melo.
description: Published as part of Mateussi, Nadayca T. B., Oliveira, Claudio & Pavanelli, Carla S., 2018, Taxonomic revision of the Cis-Andean species of Mylossoma Eigenmann & Kennedy, 1903 (Teleostei: Characiformes: Serrasalmidae), pp. 275-309 in Zootaxa 4387 (2) on pages 287-293, DOI: 10.11646/zootaxa.4387.2.3, http://zenodo.org/record/1187412