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 2017 factsheet.
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.
is 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
Castro in 1999
mentioned this species as a Microglanis sp.
on his comments on miniaturization and heterochrony.
Rhyacoglanis paranensis-dorsal view
Four new species
are described (2017): 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;
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.
the upper Rio Paraná basin, Brazil.
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.
Care & Compatibility
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
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.
From the Greek rhyax = torrent
+ glanis = catfish; indicating a catfish inhabiting
running waters in reference to the habitat of the genus.
Gender masculine. paranensis:
The specific name, paranensis,
is an adjective in reference to the occurrence of the
species in the upper Rio Paraná basin.
fin: Fleshy finlike projection without rays,
behind the rayed dorsal fin.
Anal fin: The median, unpaired, ventrally located
fin that lies behind the anus, usually on the posterior
half of the fish.
Caudal fin:The tail.
Caudal peduncle: The narrow part of a fish's
body to which the caudal or tail fin is attached. Dorsal
primary rayed fin(s) on top of the body. Hyaline:
Transparent or clear without pigment.
median bone on the upper surface of the back of the
head; pertaining to the occiput.
David pers. comm. 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