Hypopomidae

Steatogenys elegans (Steindachner).

Figure 1.Upper jaw in ventral view of cleared and stained specimen of Brachyhypopomus (Odontohypopomus) walteri sp. n. (ANSP 194025) showing teeth present on the premaxillae. PMX=premaxilla, MX=maxilla, MET=mesethmoid, PAL=ossified element within palatine cartilage (not stained), VET=ventral ethmoid.

Figure 2.Electric organ discharge (EOD) waveforms of Brachyhypopomus walteri sp. n.and Brachyhypopomus bennetti sp. n. A EOD of holotype specimen of Brachyhypopomus walteri sp. n. B EODs of nine paratypes of Brachyhypopomus walteri sp. n. C EOD of holotype of Brachyhypopomus bennetti sp. n. D EODs of six paratypes of Brachyhypopomus bennetti sp. n. All are five millisecond traces with head positivity recorded upwards; water temperature between 21 and 23°C. Scale bars = 1 millisecond.

Figure 3.Holotype of Brachyhypopomus walteri, INPA 8941 (TL 163 mm, LEA 126 mm), sex undetermined, Paraná do Paracuúba, Amazonas, Brazil. Preserved whole specimen shown above close-up view of specimen immediately post-mortem. Scale bars equal 1 cm.

Figure 4.Paratypes of Brachyhypopomus walteri. A Paratype tag no. 93-55 from INPA 8880 (TL 164 mm, LEA 118 mm), sex undetermined, Ilha da Marchantaria, Rio Solimões, Amazonas, Brazil B Paratype tag no. 93-114 from INPA 8939 (TL 155 mm, LEA 125 mm), female, collected with holotype. Preserved whole specimens shown above close-up views of specimens immediately post-mortem. Scale bars equal 1 cm.

Figure 2.Electric organ discharge (EOD) waveforms of Brachyhypopomus walteri sp. n.and Brachyhypopomus bennetti sp. n. A EOD of holotype specimen of Brachyhypopomus walteri sp. n. B EODs of nine paratypes of Brachyhypopomus walteri sp. n. C EOD of holotype of Brachyhypopomus bennetti sp. n. D EODs of six paratypes of Brachyhypopomus bennetti sp. n. All are five millisecond traces with head positivity recorded upwards; water temperature between 21 and 23°C. Scale bars = 1 millisecond.

Figure 1.Upper jaw in ventral view of cleared and stained specimen of Brachyhypopomus (Odontohypopomus) walteri sp. n. (ANSP 194025) showing teeth present on the premaxillae. PMX=premaxilla, MX=maxilla, MET=mesethmoid, PAL=ossified element within palatine cartilage (not stained), VET=ventral ethmoid.

Figure 5.Distribution of examined specimens of Brachyhypopomus walteri sp. n. (blue circles) and Brachyhypopomus bennetti sp. n. (red diamonds). Common holotype locality for both species indicated by yellow star.

Figure 6.Holotype of Brachyhypopomus bennetti, INPA 39560 (TL 215 mm, LEA 171 mm), female, Paraná do Paracuúba, Amazonas, Brazil. Preserved whole specimen shown above close-up view of specimen immediately post-mortem. Scale bars equals 1 cm.

Figure 7.Paratypes of Brachyhypopomus bennetti. A Paratype tag no. 93-214 from INPA 39581 (TL 175 mm, LEA 150 mm), female, Lago Janauari, Amazonas, Brazil B Paratype tag no. 93-137, INPA 8940 (TL 190 mm, LEA 167 mm), Lago Janauari. Preserved whole specimens shown above close-up views of specimens immediately post-mortem. Scale bars equal 1 cm.

Figure 8.Paratypes of Brachyhypopomus bennetti sp. n. (top 3) and Brachyhypopomus walteri sp. n. (bottom 3) showing transparency of electric organ to transmitted light and comparative depth of the electric organ in the two species.

Figure 2.Electric organ discharge (EOD) waveforms of Brachyhypopomus walteri sp. n.and Brachyhypopomus bennetti sp. n. A EOD of holotype specimen of Brachyhypopomus walteri sp. n. B EODs of nine paratypes of Brachyhypopomus walteri sp. n. C EOD of holotype of Brachyhypopomus bennetti sp. n. D EODs of six paratypes of Brachyhypopomus bennetti sp. n. All are five millisecond traces with head positivity recorded upwards; water temperature between 21 and 23°C. Scale bars = 1 millisecond.

Panasonic DMC-FZ50

Figure 5.Distribution of examined specimens of Brachyhypopomus walteri sp. n. (blue circles) and Brachyhypopomus bennetti sp. n. (red diamonds). Common holotype locality for both species indicated by yellow star.

NIKON CORPORATION NIKON D80

NIKON CORPORATION NIKON D80

Panasonic DMC-FZ50

NIKON CORPORATION NIKON D80

Canon Canon EOS DIGITAL REBEL XSi

Locality: Paso Mazangano, Cerro Largo, Uruguay.

Brachyhypopomus beebei (Lake January, Brazil). Artist: Burkhardt, Jacques. Title: Brachyhypopomus beebei (Lake January, Brazil). Description: Taxonomic Classification: Animalia--Hypopomidae--Brachyhypopomus beebei (Schultz 1944). Common Name: Knifefish. Medium: watercolor on paper. Dimensions: 20 x 29 cm. Collection: Harvard University. Current location: Ernst Mayr Library. Accession number: MH:MCZArtwork ARC_209-135. Inscriptions: grandeur Nat. Lago Hyanuary J. Burkhardt--Burkhardt, Jacques. Notes: 1 fish drawing (2 x 14 cm.). Source/Photographer: Harvard CURIOSity Collection - Jacques Burkhardt Scientific Drawings: http://id.lib.harvard.edu/curiosity/jacques-burkhardt-scientific-drawings/33-ARC_209-135. Permission(Reusing this file): The organization that has made the Item available believes that the Item is in the Public Domain under the laws of the United States, but a determination was not made as to its copyright status under the copyright laws of other countries. The Item may not be in the Public Domain under the laws of other countries. Please refer to the organization that has made the Item available for more information (URI: https://rightsstatements.org/page/NoC-US/1.0/?language=en).