New Parakysis from Borneo

Post by **Silurus** » 12 Mar 2003, 02:34

Ng, H. H. & M. Kottelat, 2003. Parakysis notialis, a new species of akysid catfish from Borneo (Siluriformes: Akysidae). Ichthyological Research 50: 48-51.
Pdf available from me. I don't have glossies, because the people at Springer Verlag are freakin' vultures.

Post by **Dinyar** » 12 Mar 2003, 15:54

Read with interest, thanks. A few follow-up questions that I thought I'd post here so others could also benefit from the discussion...

1) What's the difference(s) between Paraakysis and Akysis?

2) What other genera does Akysidae contain?

3) Geographical range of the family (and principal genera)?

4) Just how common are they in their natural biotope?

BTW, for those of you who haven't checked out the latest Catfish of the Month, it's on Acrochordonichthys rugosus and is written by Heok Hee.

Dinyar

Post by **Silurus** » 12 Mar 2003, 16:12

What's the difference(s) between Parakysis and Akysis?

Internally, there are a fair number of differences, but externally, the easiest way to tell them apart is the fact that Parakysis lacks a distinct adipose fin (present in Akysis) and has a long,low adipose ridge instead. The tubercles of Parakysis are not arranged in distinct rows along the sides of the body, and lastly, the mandibular barbels of Parakysis are branched (sort of like in Synodontis, but not as elaborate).

What other genera does Akysidae contain?

Three other genera: Akysis, Acrochordonichthys and Breitensteinia. I have kept (or attempted to keep) all four genera in aquaria before.

Geographical range of the family (and principal genera)?

Mostly restricted to Southeast Asia, although Akysis can be found as far west as Myanmar. Akysis is the most diverse of the four genera (abbout 20 species). Undescribed species are still surfacing fairly constantly.

Just how common are they in their natural biotope?

Akysis is fairly common when you find them in streams. They are usually found congregating among submerged vegetation in fast-flowing streams. I know of sites where one can easily catch upwards of 50 individuals with a few hours' work. The other three genera are much rarer, with Breitensteinia being the most difficult to obtain, primarily because it inhabits the swift-flowing bottoms of fairly large rivers.
Parakysis is fairly rare, too. I have never caught more than 10 individuals at one spot. Some species seem to enjoy hiding in submerged grassy vegetation along the banks of streams with a good current, and others can be found in blackwater swamps.
fascinating fish to keep in the aquarium. Very poor swimmers, they move around by levering themselves off the substrate using their pelvic fins and "hopping".