FIGURE 1 |
Lateral view of live Tenebrosternarchus preto. A. MUSM 54656 (243 mm TL) from the río Amazonas at Iquitos, Peru; B. ANSP 207797 (232 mm TL) from the rio Negro downstream from Barcelos, Brazil; and C. Detail of the head of ANSP 207797 (232 mm TL).
FIGURE 2 |
CT scan reconstructions of Tenebrosternarchus preto, MUSM 59447 (male) 264 mm TL in dorsal A., ventral B., and lateral C. views.
FIGURE 3 |
Illustrations of the neurocranium of Tenebrosternarchus preto MUSM 54617 (198 mm TL) in dorsal A., ventral B., and lateral C. views. Cartilage shown in black. Abbreviations: bao, basioccipital; epo, epioccipital; fro, frontal; let, lateral ethmoid; met, mesethmoid; obs, orbitosphenoid; par, parietal; pas, parasphenoid; pro, prootic; pto, pterotic; pts, pterosphenoid; soc, supraoccipital; spo, sphenotic; vet, ventral ethmoid; vom, vomer.
FIGURE 4 |
Suspensorium, opercular series, and lower jaw of Tenebrosternarchus preto, MUSM 54617 (198 mm TL) in A. lateral and B. medial view (image reflected). Thin, unstained hard tissue associated with opercular bones shown in light gray. Abbreviations: ang, anguloarticular; ap, autopalatine cartilage; cm, coronomeckelian; d, dentary; enp, endopterygoid; h, hyomandibula; iop, interopercle; m, Meckel’s cartilage; mpt, metapterygoid; op, opercle; pop, preopercle; q, quadrate; rar, retroarticular; sym, symplectic.
FIGURE 5 |
Maxilla of Tenebrosternarchus preto.
A. MUSM 54617 (198 mm TL) in lateral view; and B. the paired premaxillae of the same specimen in ventral view.
FIGURE 6 |
Elements of the ventral hyoid arch of Tenebrosternarchus preto in A. lateral and B. ventral view MUSM 54617 (198 mm TL). Anterior facing left. Abbreviations: br, branchiostegal; cha, anterior ceratohyal; chp, posterior ceratohyal; hhd, dorsal hypohyal; hhv, ventral hypohyal; uh, urohyal.
FIGURE 7 |
Gill arches of Tenebrosternarchus preto, MUSM 54617 (254 mm TL) Ventral arches A. shown in dorsal view and dorsal arches B. in ventral view. Abbreviations: bb, basibranchial; bh, basihyal, cb, ceratobranchial; eb, epibranchial; hb, hypobranchial; iph, infrapharyngobranchial; uptp, upper pharyngeal toothplate.
FIGURE 8 |
Cephalic lateral-line bones of Tenebrosternarchus preto, MUSM 54617 (198 mm TL). Abbreviations: ant, antorbital; io, infraorbital; na, nasal; otc, otic canal; mco, mandibular canal ossicles; pa, parietal canal; poc, postotic canal; prc, preopercular canal; soc, supraorbital canal; stc, supratemporal canal; trc, trunk canal.
FIGURE 9 |
Displaced hemal spine configuration of Tenebrosternarchus preto, MUSM 54617 (198 mm TL). Abbreviations: adhs, anterior displaced hemal spine; hs, hemal spine; pp, parapophysis; pdhs, posterior displaced hemal spine.
FIGURE 10 |
Pectoral girdle of Tenebrosternarchus preto, MUSM 54617 (198 mm TL) in lateral A., and medial B. views. Abbreviations: cl, cleithrum; co, coracoid; pt, posttemporal; ptg, propterygium; ra, radial; sca, scapula; scl, supracleithrum.
FIGURE 11 |
Heads of male Tenebrosternarchus preto
A. ANSP 198373 (302 mm TL) from the río Apure at San Fernando de Apure, Venezuela B. MUSM 59463 (291 mm) and C. MUSM 59447 (320 mm TL) both from the río Nanay at Iquitos, Peru.
FIGURE 12 |
Collection localities of Tenebrosternarchus preto, star indicating type locality. Some points indicate multiple collections or lots from proximate locations.
FIGURE 13
| Phylogenetic position of
Tenebrosternarchus (dark blue rectangle) within the Navajini modified from
Bernt et al., 2019Bernt MJ, Tagliacollo VA, Albert JS. Molecular Phylogeny of the Ghost Knifefishes (Gymnotiformes: Apteronotidae). Mol Phylogenet Evol. 2019; 135:297-307. https://doi.org/10.1016/j.ympev.2019.02.019
https://doi.org/10.1016/j.ympev.2019.02....
. Topology is a summary of maximum likelihood and Bayesian analyses of seven concatenated loci from
Bernt et al. (2019)Bernt MJ, Tagliacollo VA, Albert JS. Molecular Phylogeny of the Ghost Knifefishes (Gymnotiformes: Apteronotidae). Mol Phylogenet Evol. 2019; 135:297-307. https://doi.org/10.1016/j.ympev.2019.02.019
https://doi.org/10.1016/j.ympev.2019.02....
. All nodes shown in this topology have bootstrap support values at or above 85% and posterior probabilities above 0.90.
FIGURE 14 |
Sample of diversity of maxilla shape in Apteronotidae, emphasizing the Navajini. Maxillae are illustrated in lateral view and are not drawn to scale.
FIGURE 15 |
Apteronotids collected by ornamental fish wholesalers tentatively identified as male Tenebrosternarchus preto exhibiting hypertrophied jaws and everted teeth. A. Specimen locality unknown, photo courtesy of Kazuyuki Muramatsu. B. Specimen collected in the vicinity of Iquitos, PE, photo courtesy of Minoru Matsuzaka.