PlanetCatfish.com

We've in the past discussed how it's odd that P. disjunctivus is so rare in the trade yet show up everywhere P. pardalis gets naturalized, and how this might suggest they're really the same species. Well, I'd say this study pretty much clinches it, although without samples of wild disjunctivus it is also possible all P. pardalis in the aquarium trade are hybrids.

I find the latter much more likely purely given the forces of economics. Why use wild caught expensive plecos for your start-up project when $10 adults are available and no one has really looked at the similar ones in terms of what species.

Jools

Jools wrote:I find the latter much more likely purely given the forces of economics.

As far as I know P. disjunctivus has never been common in the trade, so unless someone specifically looked for it to produce hybrids I find it unlikely to be among the founders of the captive pardalis population. My suspicion would instead be that "disjunctivus" is an ecophenotype of pardalis, and that this is why it shows up among feral pardalis yet is rarely seen in aquarium.

I'm not sure it isn't common in the trade.

Jools

Interesting paper.

Real shame they couldn't get wild P. disjunctivus from the Madeira to get a better answer on this.

I think either hypothesis they present is plausible, but I think I favour the idea that "P. disjunctivus" is a local phenotype which may be conspecific. It may be that P. disjunctivus is nested within a widely distributed and variable P. pardalis group.

Can anyone get hold of the description of P. disjunctivus? Might shed a bit of light on these ideas.

Reference is: [CoF ref. 19114] Weber, C. (1991) Nouveaux taxa dans Pterygoplichthys sensu lato (Pisces, Siluriformes, Loricariidae). Revue Suisse de Zoologie v. 98 (no. 3): 637-643. [English summary.]

Given the amount of damage these species are causing, I think knowing what they are and where they came from is of primary concern.

racoll wrote:Can anyone get hold of the description of P. disjunctivus? Might shed a bit of light on these ideas.

Reference is: [CoF ref. 19114] Weber, C. (1991) Nouveaux taxa dans Pterygoplichthys sensu lato (Pisces, Siluriformes, Loricariidae). Revue Suisse de Zoologie v. 98 (no. 3): 637-643. [English summary.]

The description does not include a proper description, only a diagnosis, which basically describes its vermiculated pattern on the belly and head as being different from that of pardalis. The paper also includes a key that is pretty much the same as Armbruster's key, except in French.