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AMAZONAS
16
AQUATIC
Peckoltia otali is another 3–3.5-inch (8–9-cm) long brown Peckoltia species
with black spots connecting to form irregular bands. It is one of the smaller
Peckoltia species in which males are very heavily bristled, and may be fairly
closely related to two species well known in the aquarium hobby, namely L
038 and L 080. Hence it is not surprising that during the bar-coding, Fisch-
Muller et al. established striking differences between this and the other two
new Peckoltia species, which they classified as genetically fairly close to P.
oligospila.
The species Panaqolus koko is likely to be the subject of future major discussion
among ichthyologists, as it is a very unusual fish. When I examined
this species in detail before the publication of its description, I classified it as a
member of an undetermined genus, as the combination of body form, odontode
(dermal tooth) growth, and dentition distinguished it from all other
genera known to me to date.
I found its assignment to the genus Panaqolus very surprising, as all other
members of the genus that I am aware of possess a broader body form and
spatulate teeth with a single cusp. Only Panaqolus maccus purportedly (according
to Schaefer & Stewart 1993) exhibits a certain variability in dentition
when young, with a possible second cusp.
The new Panaqolus koko is uniform black-brown in color, with an unusually
pointed head and slender form. All the specimens I have examined are
thought to be half-grown and already have unusually striking odontodes such
as I have never previously seen in any other Panaqolus species at this age. And
while the teeth were spatulate overall, they were unusually large and possessed
a second large lateral cusp. The species may attain a total length of around
4.3–4.7 inches (11–12 cm).
Is Hemiancistrus monotypic?
Ichthyologists have hitherto avoided differentiating the catch-all genus Hemiancistrus
from Peckoltia; in the past it has been a depository mainly for assorted
black-spotted armored catfishes that don’t fit well in other genera. But
Fisch-Muller et al. have established that Hemiancistrus medians, type species of
the genus Hemiancistrus, is not closely related to Peckoltia and Panaqolus.
The authors believe the genus Hemiancistrus should be regarded as monotypic,
as the other species currently assigned to this genus are probably not
closely related to the type species.
Hemiancistrus medians is a very unusual loricariid, which may now also
have been imported alive to Europe, probably for the first time, by Panta Rhei
GmbH. This armored catfish, which grows to around 9.8 inches (25 cm) long,
is most closely reminiscent of the members of the genus Baryancistrus, but
has unusually large eyes, heavily ridged scutes on the sides of the body, and
truly extraordinary papillae in the mouth cavity. The smaller specimens have
noticeably fewer, but extremely large black spots on the body, and these become
smaller and more numerous with increasing age. These black spots look
very attractive on the yellowish-brown background.
REFERENCES
NOTEBOOK
Armbruster, J.W. 2004. Phylogenetic relationships of the suckermouth armoured catfishes
(Loricariidae) with emphasis on the Hypostominae and the Ancistrinae. Zool J Linn Soc 141: 1–80.
Fisch-Muller, S., J.I. Montoya-Burgos, P.-Y. Le Bail, and R. Covain. 2012. Diversity of the Ancistrini
(Siluriformes: Loricariidae) from the Guianas: the Panaque group, a molecular appraisal with
descriptions of new species. Cybium 36 (1): 163–93.
Schaefer, S.A. D.J. Stewart. 1993. Systematics of the Panaque dentex species group (Siluriformes:
Loricariidae), wood-eating armored catfishes from tropical South America. Ichthyol Expl Freshw 4 (4):
309–42.