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T. WEIDNER
members of the small family Odontobutidae, the freshwater
sleeper gobies. The species was described from
the New Territories of Honking, but these fishes are
hardly ever found there now and our imports originate
from less disturbed areas of the Chinese mainland.
The male in the photo is still relatively young. With
age, these fishes are said to develop an impressively
high forehead and become rather thuggish. My male
was thuggish long before that, and it only took him
a few hours to dispatch the less attractive female to
fishy heaven. These fishes have proved to be sensitive
to transportation and need time to regain their strength
after shipping. So far there are no reports of the successful
breeding of this attractive species.
Biotodoma wavrini “Rio Preto da Eva”,
Orinoco Eartheater
—Hans-G. Evers
Normally Biotodoma wavrini, the Orinoco Earthe-
6| ater, is found in the drainage of the Orinoco
in Colombia and Venezuela, as well as in the upper
course of the Río Negro. However, it seems that a
small enclave of Biotodoma wavrini has become established
in the drainage of the Río Preto da Eva in Brazil,
which lies hundreds of kilometers from the actual
distribution region of this species.
In 2011 Aquarium Glaser imported a small group
of the Río Preto da Eva population, and I acquired the
Orinoco Eartheater,
Biotodoma wavrini
entire batch. At the same time they were also selling
Biotodoma wavrini of around the same size from the
drainage of the Orinoco and imported from Colombia. A
number of these fish also found a home in my aquarium
cellar for the purpose of comparison.
Because the Biotodoma species can be classified,
at least roughly, in the aquarium hobby on the basis of
the shape and position of the lateral spot, I hoped to
be able to detect at least marginal differences, but, unfortunately,
I found no reliable criteria, and there were
no obvious differences in the body form.
There are differences in the form of the fins: in
adult specimens of the Río Preto da Eva population,
the unpaired fins are noticeably longer and have more
delicate filaments. Were I to add that the Río Preto
da Eva fishes are significantly more attractive in color,
I would get a few scornful looks, but although both
populations have a white-wine base color, the flanks of
the Río Preto da Eva fishes are overlain with soft bluegreen
shades and the soft-rayed parts of the unpaired
fins are reddish.
I had secretly hoped that it would be possible to
definitively distinguish the two populations, as their
geographical separation is so great that it is hard to
believe they are the same species. I am not aware of
any molecular-biological or morphological studies on
the two populations, so for the time being I am forced
to assume that they are one and the same species.
—Thomas Weidner
AMAZONAS 93