Shibatta & Vari, 2017
hyacoglanis, a new genus of the South American freshwater
catfish family Pseudopimelodidae is described from cis-Andean
portions of the continent and was only described this year (2017)
and so this new genus and species is our subject for our July
This new genera and species has a
long chequered past with the first pictures of this species
appearing in the 3rd volume of Catfishes of the World (Auchenipteridae
and Pimelodidae) By David Sands as far back as 1984 with
David having importing them 5 years previously from Sao
Paulo in 1979. You have to remember that the Pseudopimelodidae
had yet to be assigned by Lundberg, Bornbusch & Mago-Leccia,
1991 as a sub-family of Pimelodidae.
distinguished from other genera of the family by three synapomorphies:
presence of a light blotch on the cheek; a connection between
the middle of the dark caudal-fin stripe and the dark caudal-peduncle
pigmentation; and 30-35 total vertebrae. Species of Rhyacoglanis
are rheophilic and strongly associated with rapids and other
swift-flowing waters. A phylogenetic analysis based on 41
morphological characters yields a hypothesis of monophyly
of the Pseudopimelodidae and Rhyacoglanis. Pimelodus
pulcher Boulenger, 1887, from the western Amazon basin
is designated as type-species of the new genus and redescribed.
Castro in 1999 mentioned this species
as a Microglanis sp. on his comments on miniaturization
paranensis - dorsal
Four new species are described:
Rhyacoglanis annulatus, from the Río
Orinoco basin, with a nearly ringed dark band on the caudal peduncle,
and a larger distance between anus and anal-fin origin; R.
epiblepsis, from the rio Madeira basin, with numerous
dark spots scattered on the body, and rounded caudal-fin lobes;
R. paranensis, from the upper rio Paraná
basin, with three distinct dark bands on the body, and 31-33 total
vertebrae; and R. seminiger, from the
Rio Juruena basin, with subdorsal and subadipose dark bands fused
anteroposteriorly, and a separate dark band on the caudal peduncle.
Body depressed from snout tip to dorsal-fin
origin; progressively more compressed from that point to caudal-fin
base. Dorsal profile of head and anterodorsal portion of body
nearly straight from snout tip to dorsal-fin origin but slightly
concave along occipital region. Dorsal-fin base nearly straight
with slight posteroventral incline. Body profile nearly straight
from end of dorsal-fin base to adipose-fin origin. Ventralprofile
of head and body convex from lower jaw margin to end of anal-fin
base, almost straight from anus to anal-fin origin. Caudal peduncle
profile concave dorsally and ventrally.
Ground colour light brown in alcohol; light
orange in life. Head with dark spots on dorsal surface, opercle,
and region ventral to orbit. Region over adductor mandibulae muscle
lightly coloured. Iris dark in alcohol; light gray in life. Dark
subdorsal band with irregular anterior and posterior margins; extending
to ventral region of body but not contacting contralateral counterpart.
Subadipose band with irregular anterior and nearly straight posterior
margins. Lightly colored region between subdorsal and subadipose
bands with scattered dark spots. Anterior margin of caudal-peduncle
band nearly straight and posterior margin in shape of shallow, posteriorly
open sideways V. Dorsal fin with dark pigmentation covering fin
other than for distal one-fifth. Adipose fin with dark blotch centrally.
Anal fin with dark basal spot and dark stripe on midsection; two
regions conjoined posteriorly. Caudal fin hyaline basally with broad
dark band across each lobe and lobe tips largely hyaline. Pectoral
and pelvic fins hyaline except for transverse dark stripe on each.
Provide plenty of
hiding places to hide during the day and best kept in a
small group of 2-3. Very secretive in its surroundings.
A good addition to the medium sized community
tank, and will not harm the occupants unless they are small enough
to fit into its mouth such as newly born fry and young fish.
Not recorded but usually
the females are more rotund.
No problem with eating all types of aquarium
fare, flake, tablets, pellets, live and frozen foods.
A median bone on the upper
surface of the back of the head; pertaining to the occiput.
fin: The primary
rayed fin(s) on top of the body.
Anal fin: The median, unpaired, ventrally
located fin that lies behind the anus, usually on the posterior
half of the fish.
or clear without pigment..
Adipose fin: Fleshy finlike projection
without rays, behind the rayed dorsal fin.
Caudal fin: The tail.
Caudal peduncle: The narrow part of a fish's body
to which the caudal or tail fin is attached.
From the Greek rhyax = torrent + glanis
= catfish; indicating a catfish inhabiting running waters
in reference to the habitat of the genus. Gender masculine.
The specific name, paranensis, is
an adjective in reference to the occurrence of the species
in the upper Rio Paraná basin.
Shibatta, Oscar Akio, & Vari,
Richard P. (2017). A new
genus of Neotropical rheophilic catfishes, with four new species
(Teleostei: Siluriformes: Pseudopimelodidae). Neotropical Ichthyology,
15(2), e160132. Epub June 30, 2017.https://dx.doi.org/10.1590/1982-0224-20160132
David Sands; pers. comm.
Sands - From the publication: Catfishes of the
World Vol. 3. Page 64/65.