[RML] New Rainbowfish - more info!

Adrian R. Tappin (atappin at ecn.net.au)
Mon, 10 Aug 1998 16:57:03 +1000

A new genus and species of melanotaeniid, Pelangia mbutaensis, is described
on the basis of 52 specimens, 30.3-55.5 mm SL, collected in 1997 in the
Mbuta Basin near Etna Bay, Irian Jaya. The new genus is the apparent sister
group of Glossolepis, which is restricted to northern New Guinea. It differs
from Glossolepis with regards to several important features including a lack
of teeth on the vomer and palatines, a larger mouth and eye, reduced
crenulations on the scale margins, and fewer anal rays. The new genus also
differs in having the anal fin origin closer to the caudal fin base than to
the snout tip, which is the opposite situation compared to Glossolepis.
Additionally, the origin of the first dorsal fin is well ahead of the anal
fin origin, but in Glossolepis it is either even with the anal fin origin or
behind it. Finally, the second dorsal fin origin is approximately level with
the third soft anal ray in Pelangia, but in Glossolepis it is usually level
with the middle rays.

The genus is named Pelangia after the Indonesian name for rainbow
("pelangi") with reference to the common name for the family
Melanotaeniidae. The species name mbutaensis is in reference to the type
locality. The colour of the new rainbowfish is relatively dull compared to
most other members of the family. The ground colour is yellowish tan grading
to silvery white on lower half of sides. The largest males have scattered
yellow flecks along the middle of the side. Fins are mainly translucent
except for dusky grey pigmentation on the first dorsal. The difference
between sexes is far less evident in this species than in most
rainbowfishes. Males have a slightly longer first dorsal fin, which slightly
overlaps the second dorsal fin origin when depressed. By contrast, the
depressed first dorsal fin of females fails to reach the dorsal fin origin
or barely reaches it. In addition, males generally have a deeper body than
females. Melanotaenia goldiei was found in the same creek.

Gerald R. Allen, 1998
A new genus and species of Rainbowfish (Melanotaeniidae) from fresh waters
of Irian Jaya, Indonesia.
Revue Française d'Aquariologie, 25 (1-2): 11-16.

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Adrian R. Tappin
"Home of the Rainbowfish"
http://www.ecn.net.au/~atappin/home.htm
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