Fig. 1
Trichomycterus balios, holotype, UFRGS 16229, 82.0 mm SL, Brazil, Rio Grande do Sul State, municipality of São Francisco de Paula, rio Santa Cruz, rio Caí basin.
Fig. 2
Dorsal view of neurocranium of (a) Trichomycterus balios, paratype, UFRGS 6831, 81.7 mm SL; (b) T. diatropoporos, paratype, UFRGS 16237, 57.8 mm SL; (c) T. poikilos, paratype, MCP 22699, 79.0 mm SL, and (d) T. brachykechenos, paratype, UFRGS 16245, 41.9 mm SL, some elements not shown. Abbreviations: AF, anterior fontanel; AN, antorbital; AP, autopalatine; EP, epioccipital; FR, frontal; LE, lateral ethmoid; i1, infraorbital sensory branch 1; i3, infraorbital sensory branch 3; i10-11, infraorbital sensory branch 10 and 11; ME, mesethmoid; MX, maxilla; PF, posterior fontanel; PM, premaxilla; po1-2, postotic sensory branches 1 and 2; PS, posttemporosupracleithrum; PT, pterotic; s1, supraorbital sensory branch 1; s3, supraorbital sensory branch 3; s6, supraorbital sensory branch 6 (epiphyseal branch); SO, tendon-bone supraorbital; SP+PO+PN, sphenotic-prootic-pterosphenoid complex bone; SU, parieto-supraoccipital; WC, Weberian capsule. Scale bar = 2 mm.
Fig. 3
Dorsal view of gill arches (right dorsal elements and gill rakers not show) of (a) Trichomycterus balios, paratype, UFRGS 6831, 81.7 mm SL; (b) T. diatropoporos, paratype, UFRGS 16237, 57.8 mm SL; (c) T. poikilos, paratype, MCP 22699, 79.0 mm SL; and (d) T. brachykechenos, paratype, UFRGS 16244, 51.6 mm SL. Abbreviations: BB2-4, basibranchials 2 to 4; CB1-5, ceratobranchials 1 to 5; EB1-5, epibranchials 1 to 5; HB1-3, hypobranchials 1 to 3; PB3, pharyngobranchial 3; TP; tooth plate. Scale bar = 1 mm.
Fig. 4
Lateral view of left hyoid arch of (a) Trichomycterus balios, paratype, UFRGS 6831, 81.7 mm SL; (b) T. diatropoporos, paratype, UFRGS 16237, 57.8 mm SL; (c) T. poikilos, paratype, MCP 22699, 79.0 mm SL; and (d) T. brachykechenos, paratype, UFRGS 16245, 41.9 mm SL. Abbreviations: AC, anterior ceratohyal; BR1-9, branchiostegal rays 1 to 9; IC, inter-ceratohyal cartilage; PC, posterior ceratohyal; VH, ventral hypohyal. Scale bar = 1 mm.
Fig. 5
Dorsal view of urohyal of (a) Trichomycterus balios, paratype, UFRGS 6831, 81.7 mm SL; (b) T. diatropoporos, paratype, UFRGS 16237, 57.8 mm SL; (c) T. poikilos, paratype, MCP 22699, 79.0 mm SL; and (d) T. brachykechenos, paratype, UFRGS 16245, 41.9 mm SL. Scale bar = 0.5 mm.
Fig. 6
Lateral view, anterior to left, of caudal skeleton of (a) Trichomycterus balios, paratype, UFRGS 6831, 81.7 mm SL; (b) T. diatropoporos, paratype, UFRGS 16237, 57.8 mm SL; (c) T. poikilos, paratype, MCP 22699, 79.0 mm SL; and (d) T. brachykechenos, paratype, UFRGS 16244, 51.6 mm SL. Abbreviations: HA+HAS, complex hypurapophysis composed of hypurapophysis and secondary hypurapophysis; HS, haemal spine; HU3, hypural 3; HU4+HU5, complex plate formed by co-ossification of hypurals 4 and 5; HU3+HU4+HU5, complex plate formed by co-ossification of hypurals 3 to 5; NS, neural spine; PH+HU1+HU2, complex plate formed by co-ossification of hypurals 1 and 2 and parhypural; PU1+U1, complex centrum composed of preural centrum 1 and ural centrum 1; PU2, preural centrum; UR, uroneural. Scale bar = 0.5 mm.
Fig. 7
Upper caudal plates of Trichomycterus balios, lateral view, anterior to left. (a) = paratype, MCP 41292, 64.7 mm SL; (b) paratype, MCP 41292, 72.3 mm SL. Abbreviations: HU3, hypural 3; HU4+HU5, complex plate formed by co-ossification of hypurals 4 and 5; HU3+HU4+HU5, complex plate formed by co-ossification of hypurals 3, 4 and 5. Scale bar = 0.5 mm.
Fig. 8
Geographic distribution of species of Trichomycterus in the laguna dos Patos system. Some symbols represent more than one collection locality. Stars represent type localities. Trichomycterus balios (green symbols), T. brachykechenos (red symbols), T. diatropoporos (brown symbols), T. poikilos (yellow symbols), Trichomycterus cf. poikilos (yellow lozenge) and T. tropeiro (blue symbols), Abbreviations: 1, rio dos Sinos; 2, rio Caí; 3, rio das Antas; 3', rio Taquari-Antas; 4, rio da Prata; 5, rio Carreiro; 6, rio Guaporé; 7, rio Forqueta; 8, rio Pardo; 9, rio Jacuí; 10, laguna dos Patos; and 11, rio Mampituba basin.
Fig. 9
Arroio Bagual, municipality of Bom Jesus, locality of collection of some type specimens of Trichomycterus balios (a). Type locality of T. diatropoporos: rio da Prata at Passo do Despraiado, municipality of Nova Prata (b, photo by T. P. Carvalho). Type locality of T. poikilos: arroio Passo dos Buracos or Tipiaia on road BR-158, municipality of Júlio de Castilhos (c). Locality where most type specimens of T. brachykechenos (11 specimens) were collected: rio dos Sinos, municipality of Caraá (d, photo by R. B. Dala-Corte). All localities from Rio Grande do Sul State, Brazil.
Fig. 10
Trichomycterus diatropoporos, holotype, MCP 46947, 58.8 mm SL, Brazil, Rio Grande do Sul State, municipality of Nova Prata, rio da Prata at Passo do Despraiado.
Fig. 11
Right lower jaw of (a) Trichomycterus diatropoporos, paratype, UFRGS 16237, 57.8 mm SL in lateral view and (b) T. poikilos, paratype, MCP 22699, 79.0 mm SL, in medial view. Abbreviations: AR, anguloarticular; CP, coronoid process; DE, dentary; MC, Meckel's cartilage. Scale bar = 1 mm.
Fig. 12
Pelvic girdle of Trichomycterus diatropoporos, paratype, UFRGS 16237, 57.8 mm SL, dorsal view. Abbreviations: BS, basipterygium; EP, external process; IP, internal process; MP, medial process; PR, pelvic-fin rays; PS, pelvic splint. Scale bar = 1 mm.
Fig. 13
Trichomycterus poikilos, holotype, UFRGS 16239, 63.3 mm SL, Brazil, Rio Grande do Sul State, municipality of Júlio de Castilhos, arroio Passo dos Buracos or Tipiaia on road BR-158, upper rio Jacuí basin.
Fig. 14
Paratypes of Trichomycterus poikilos (UFRGS 14992, 40.5-92.5 mm SL) with ontogenetic variation in coloration. Specimens represented in scale.
Fig. 15
Trichomycterus brachykechenos, holotype, MCN 18929, 61.1 mm SL, Brazil, Rio Grande do Sul State, municipality of Caraá, rio do Sinos.
Fig. 16
Autopalatine of Trichomycterus brachykechenos, paratype, UFRGS 16245, 41.9 mm SL, dorsal view. Arrow indicates the concavity of mesial margin. Scale bar = 0.5 mm.
