It differs from epigean congeners from the São
Francisco River basin by the variable eye size, ranging
from reduced to externally invisible (bilateral asymmetry
in development of eyes is frequently observed), with
a conspicuous orbital concavity (orbital diameter
varying from 6.4 to 13.6% of head length in R.
enfurnada and from 14.5 to 24.4% in the epigean
species); by the dark pigmentation reduced due to
a decrease in density of melanophores, and also variable.
In comparison to other cave species, R. enfurnada
presents a low degree of troglomorphism regarding
development of eyes and pigmentation, indicating a
relatively short time evolving in isolation in the
subterranean environment: R. reddelli is
described as lacking eyes and with almost no pigmentation;
likewise, R. macuspanensis and R. laluchensis
as having rudimentary eyes, covered with skin and
not visible externally, and with reduced body pigmentation;
R. zongolicensis is also almost devoid of
dark pigmentation, but eyes are less reduced than
in R. reddelli. R. quelen urichi,
also does not present any trace of eyes externally,
but the body colouration is described as pale yellowish
brown. Rhamdia guasarensis has a concave
dorsal profile of head and a complete absence of pigmentation
and eyes. The population density (preliminarily estimated
in 0.1-0.2 individuals m-2 in average, and reaching
10 individuals m-2, in the dry season and size (several
thousands of individuals) of R. enfurnada
may be considered high for cave fish standards. Rhamdia
enfurnada exhibited an increased midwater activity
when compared to their typically bottom-dwelling epigean
relatives; are mostly indifferent to light and moderately
aggressive. Habitat: Rhamdia
enfurnada, is a troglobitic (exclusively subterranean)
catfish, and is described from the Gruna do Enfurnado,
Serra do Ramalho, southwestern Bahia State, middle
São Francisco River basin. Colouration.
Light grey to yellowish, with melanophores concentrated
on head region and margins of adipose and dorsal fins.
Iridophores present, concentrated on opecular region,
forming yellowish iridescent spot covering 2/3 of
do Ramalho. Type locality: Known
only from its type locality, the Gruna do Enfurnado
elevation 628 m), Serra do Ramalho, Bahia State, middle
São Francisco River basin, northeastern Brazil..
Bichuette, M.E. and
E. Trajano, 2005. A new cave species of Rhamdia
(Siluriformes: Heptapteridae) from Serra do Ramalho,
northeastern Brazil, with notes on ecology and behavior.
Neotrop. Ichthyol. 3(4):587-595. Froese, R. and D. Pauly.
Editors. 2017. FishBase. World Wide Web electronic
publication. www.fishbase.org, ( 06/2017 ).