Rhabdolichops navalha Correa, Crampton & Albert, 2006

Family:  Sternopygidae (Glass knifefishes)
Max. size:  16.1 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater; depth range 5 - 10 m
Distribution:  South America: Brazil.
Diagnosis:  Diagnosis: Distinguished from its congeners by the following unique characters: an unusual electric organ (EO) morphology in which the posterior EO margin ends abruptly and is replaced by rigid and transparent non-electrogenic tissue in the posterior, approximate one-half of the caudal appendage; very visible hemal spines in the posterior half of the caudal appendage; presence of 5 (vs. 6 or 7) pairs of pleural ribs; oral teeth conical, with diameter at base more than at midlength (vs. villiform, about as wide at base as at midlength in all congeners; cleithral posterior process broad (vs. narrow in all congeners). Also, it differs from its congeners, except with R. stewarti, in possessing non-ossified gill rakers, and except R. electrogrammus and R. caviceps, in possessing a distinct "black cap" (dense region of dark chromatophores in the parietal region) (Ref. 55969).
Biology:  This species is known only from the main channel of the low-nutrient blackwater Rio TefĂ©. Apparently, the species is a benthic specalist. It is captured in trawl nets where it occurs with Rhabdolichops eastwardi, troscheli, caviceps, nigrimans, and electrogrammus, except lundbergi. Its diet consists of small planktonic crustacean primarily Cladocera and Copepoda, but also small Conchostraca and Ostracoda (Ref. 55969).
IUCN Red List Status: Least Concern (LC); Date assessed: 07 November 2018 Ref. (126983)
Threat to humans:  harmless

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