American ichthyologists John Sullivan and Carl Hopkins have described a new species of electric knifefish, publishing the description of Brachyhypopomus bullocki in the most recent issue of the Proceedings of the Academy of Natural Sciences of Philadelphia.
The new species, named after neurobiologist Theodore Holmes Bullock, can be distinguished from congeners in having a combination of the caudal filament exceedingly long in reproductive males, to 45% total length; 6"11 wide, evenly spaced saddles of pigment over the back connecting to lateral bands; mesocoracoid present; large eye, 15.5"19.2% head length; short abdomen, usually with 12 pre-caudal vertebrae; and third and fourth (outermost) branchiostegal rays poorly ossified, much enlarged distally, covering distal portions of the first two branchiostegal rays externally and contributing to a bulbous appearance of opercular region.
Picture kindly supplied by John Sullivan.
The authors write that Brachyhypopomus bullocki ...is often found in clear, shallow, standing water in open savanna, or savanna mixed with stands of Mauritia palm.
It has also been collected in the vegetation along the banks of small pools fed by streams.
Typically, individuals are found quiescent during the day among the stems and roots of emergent grasses and sedges. The individual from the rio Negro was collected in palm leaf litter near the outlet of a black water stream. This species has only been found in very low conductivity water (