Fig 1.
Lateral view of Eigenmannia sirius, MZSUP 121668, holotype, 127.5 mm LEA, Mato Grosso, Brazil, rio Mutum, tributary of rio Juruena, rio Tapajós basin.
Fig 2.
Infraorbital 1+2 of Eigenmannia sirius, MZUSP 118582, 93.3 mm LEA, paratype.
Arrow indicates the posterodorsal expansion. Scale bar = 1 mm.
Fig 3.
Osteological elements of Eigenmannia sirius: A) premaxilla (MCP 41099, 88.7 mm LEA); B) dentary, C) maxillary bone (MZUSP 118582, 93.3 mm LEA); D) suspensorial bones (MZUSP 118581, 110.5 mm LEA); E) infraorbital series (MCP 41099, 88.5 mm LEA).
Ag = anguloarticular; An = antorbital; Cb = coronomeckelian bone; Ct = connective tissue; De = dentary; En = endopterygoid; Hy = hyomandibula; Io = infraorbital; Ip = interopercle; Mt = Metapterygoid; Mx = maxillary bone; Mc = meckel’s cartilage; Op = opercle; Pe = posterodorsal expansion of Infraorbitals 1+2; Po = preopercle; Qd = quadrate; Re = retroarticular; So = subopercle; Sy = symplectic bone.
Fig 4.
Lateral view of Eigenmannia sirius, MCP 41099, paratype, 75.6 mm LEA, Mato Grosso, Brazil, rio Mutum, tributary of rio Juruena, rio Tapajós basin.
Fig 5.
Color in life of Eigenmannia sirius, MZUSP 123938, paratypes, 93.7 and 77.3 mm LEA, A and B respectively, rio Mutum, rio Juruena, Mato Grosso, Brazil.
Caudal filament damaged.
Fig 6.
Computed tomography renderings of anterior portion in lateral (A), dorsal (B) and ventral views (C) of Eigenmannia sirius, MZSUP 121668, holotype, 127.5 mm LEA.
Af = anterior fontanelle; Ag = anguloarticular; Ao = antorbital; Ap = anterolateral process of premaxilla; Bh = basihyal; Bo = basioccipital; Br = branchiostegal rays; Cl = Cleithrum; Clo = crest of the levator arcus palatini; Co = coracoid; De = dentary; En = endopterygoid; Ep = endopterygoid process; Ex = exoccipital; Ext = extrascapular; Fb = filamentous bone; Fr = frontal; Hd = hypohyal dorsal; Hv = hypohyahl ventral; Hy = hyomandibula; In = Interopercle; Io = infraorbitals; Le = lateral ethmoid; Me = mesethmoid; Mt = metapterygoid; Mx = maxillary bone; Na = nasal; Op = opercle; Or = orbtosphenoid; Pa = parietal; Pc = postcleithrum; Pfr = pectoral-fin rays; Pf = posterior fontanelle; Pm = premaxilla; Po = preopercle; Pp = parasphenoid; Pr = prootic; Ps = pterosphenoid; Pt = pterotic; Qd = quadrate; Re = retroarticular; So = subopercle; Sca = scapula; Sc+Pt = suptracleithrum+posttemporal; So = supraoccipital; Sp = sphenotic; Ur = urohyal; Vo = vomer.
Fig 7.
Computed tomography renderings of anterior portion in left lateral (A) and right inverted oblique (B) views of Eigenmannia sirius, MZSUP 121668, holotype, 127.5 mm LEA.
Fig 8.
Lateral view of the dorsolateral head muscles of the Eigenmannia sirius, MCP 41099, paratype, 97.6 mm LEA.
AM = adductor mandibulae; Io = infraorbitals; LO = levator operculi; Mx = maxillary bone; Rmt = ramus mandibularis trigeminus; Sc = supracleithrum canal.
Table 1.
Morphometrics for examined specimens of Eigenmannia sirius, new species.
SD = Standart Deviaton.
Fig 9.
Map of the upper portion of rio Tapajós basin, showing the locality of Eigenmannia sirius.
Star represents more than one lot.
Fig 10.
Photograph of rio Mutum, type locality of Eigenmannia sirius, illustrating habitat.
Fig 11.
Lateral view of adductor mandibulae, segmentum facialis (A) and medial view of adductor mandibulae, pars malaris (B) of Sternopygus astrabes, MZUSP 88795, 151.0 mm LEA.
Am = adductor mandibulae; An = anguloarticular; Bm = buccopalatal membrane; De = dentary; El = endomaxilar ligament; Io = infraorbital; Mx = maxillary bone; Re = retroarticular. Endomaxilar ligament and buccopalatal membrane dissected. Scale: 3 mm.
Fig 12.
Lateral view of adductor mandibulae, pars malaris of Rhamphichthys hahni, MZUSP 24736, 479.5 mm.
Am = adductor mandibulae; Ao = antorbital; Bm = buccopalatal membrane; El = endomaxilar ligament; Ela = endomaxilar ligament accessory; Mx = maxillary bone. Scale: 1 cm.
Fig 13.
Lateral view of the dorsolateral head muscles of: A) Rhabdolichops troscheli, MZUSP 57704, 104.2 mm LEA and B) Sternopygus macrurus, MPEG 22756, 245.8 mm LEA.
Am = adductor mandibulae; Io = infraorbital; Mx = maxillary bone; Sc = supracleithrum + posttemporal canal; LO = Levator operculi; Rmt = ramus mandibularis trigeminus. Recurrent ramus of anteroventral part of anterior lateral line nerve in green. Scales: 3 mm (A) and 1 cm (B).
Fig 14.
Lateral view of the dorsolateral head muscles of Gymnotus cylindricus, USNM 134701, 178.5 mm LEA.
Am = adductor mandibulae; Io = infraorbital; LO = levator operculi; Mx = maxillary bone; R-avn = recurrent ramus of anteroventral part of anterior lateral line nerve; Rmt = ramus mandibularis trigeminus. Posterodorsal portion of LO, posterior accidentally removed. Scale: 4 mm.
Table 2.
Taxonomic arrangement of species group in Eigenmannia.