Synodontis grandiops & S. multipunctatus

lfinley58 · Post by **lfinley58** » 05 Jan 2007, 22:59

Hello all.

I was mixed as to where to put this post. It relates to a topic dealing with the recently published revision of the Lake Tanganyikan Synodontis species. The initial post on this topic has grown long and I felt it better to maybe start a new string or two to address separate topics relating to this. If the moderators feel that this should be somewhere else please feel free to move it. I will add that if you have not read that thread it might be good to do so.

In the revision noted above, a new species, Synodontis grandiops, is described. It is very close to S. multipunctatus and in fact the color descriptions of the two species, with only very minimal differences having nothing to do with the color, are identical. There are a number of features noted that differentiate the two species and the most notable (from our, or at least my, point of view) among these is the size of the eye. The eye size in S. grandiops is larger that that of S. multipunctatus. The way the eye size is stated is as a percent of snout length. In S. grandiops this is noted to range from 64.2 to 81% of the snout length. In S. multipunctatus it is 44.9 to 62.0%. At the extremes these differences would be, and are, quite noticable. But, reality must also be taken into account.

To explore this aspect of the two species I downloaded and printed out some selected pictures from the S. multipunctatus section of the Cat-elog on this site (these were basically lateral views having reasonable resolution). As a control, I also downloaded Erwin Schraml's photo of the type specimen of S. multipunctatus from the All Catfish Species Inventory website (by using this I had a picture of a fish in which the specific measurements were presented in the revision). I won't go to crazy here with all of the details (unless someone really wants to know), but basically following the same measurement standards that were used in the revision I measured the size of the eye and the lengths of the snouts from the photos. From there, using a little math I came up with the percentage size of the eyes in the snout lengths.

It was not possible to do all photos, so as noted, I selected certain ones. For now, I would like to make note of two of these.

Photo, or image, number one - In just looking at this picture it is easy to note the large eye. My measurements (admittedly rough based on a number of considerations), show this specific fish to have an eye size that is approximately 78% of the snout length. So, as far as I am concerned this particular fish is easily diagnosable as S. grandiops.

Photo, or image, number sixteen - Visually, compared to the length of the snout, this fish has a smaller eye. My measurements on this place the eye at about 48% of snout length. So this fish would fit nicely into the measurements that were provided for S. multipunctatus and I consider it as such.

So, there is a little start to try to straighten out the situation with these two species which are among us in the hobby. I also pulled out some photos that I had taken in 1977 and subjected them to the same measurements and (son of a gun) found out to my interest (and satisfaction) that I had S. grandiops way back then.

One addtional note: in the revision it is stated that it is not known whether S. grandiops has a cuckoo style of reproduction as is known in S. multipunctatus. If my methods of measurements are correct it can be said that both species practice a similar style of reproduction. This is based on doing the same type of measurements on a limited number of existing spawning act photos that I looked at. I shall be doing more of these for further confirmation.

As copies of the revision get into more hands we will hopefully see additional thoughts and comments regarding the various covered species posted on PC. I know that Steve Grant has a copy heading his way and I will look forward to some of his analysis on the topic.

Lee

Richard B · Post by **Richard B** » 07 Jan 2007, 20:49

Thanks for the heads-up Lee & providing us all with a good start.

I am going to re-decorate soon & as the fish will go into storage at my LFS i will use this opportunity to get some photos of my 16 "Multis/grandiops" as there is a vast variation between them & may post some for discussion.

Do you think that there has been the possibility of any cross breeding between these two species in the scenario where different sex individuals are kept in aquariums? If this is a possibility it may add to the multiple variations we have seen - i'd appreciate your thoughts

All the best

Richard B

lfinley58 · Post by **lfinley58** » 07 Jan 2007, 21:58

Hi Richard,

Will look forward to your pictures. I'd think getting pictures of each eye size extreme within your group of 16 (and some in the middle) would be very interesting.

If you are up to trying some examinations and counts, it would be useful to hear of the number of pectoral fin ray counts on the photographed fishes. In the paper it is noted that S. multipunctatus always has 8 pectoral fin rays, while S. grandiops always has 7.

As for potential cross breeding in aquarium held fishes - with the gang spawning approach that these fishes can get involved in, the mind boggles at the thought of it. As Oliver Hardy would say "This is another fine mess you've gotten us into." This might, as you note, possibly account for some "variations" and must certaily be consided whether we like it or not.

Will look forward to hearing, and seeing, your results.

Lee

Richard B · Post by **Richard B** » 11 Jan 2007, 13:14

Hi Lee

Not too long now till redecorating so results (of one kind or another soon.

For information - how is the snout measurement taken? I am presuming the eye size is a horizontal diameter.

Further, i am presuming from the indication you previously gave - photo 1 (grandiops) is the one with the blue background & the multipunctatus is photo 16 the southern variation?

Many thanks

Richard B

lfinley58 · Post by **lfinley58** » 11 Jan 2007, 13:26

Hi Richard,

Yes, the two fishes that you mention are the ones that I used as measurement examples. They were chosen in that they show extremes of eye/snout ratio.

Regarding the measurements - yes, the eye is measured horizontally across the middle. The snout measurement is from the tip of the snout to the anterior edge of the eye (with the morphology involved this is necessarily at a bit of an angle). Poll's method of doing this measurement (which was used in the new paper) shows it being done on a laterally placed fish.

Will be looking forward to your results.

Lee

YouTube · Post by **Jools** » 29 Jan 2007, 15:05

Just a quick note to say I'm keeping track of this and once I get my copy of the work will try and move the fish around accordingly.

I very much appreciate stuff like "image one is XXXX because YYYY" as not only can I move images to more correct ids, but I have a reason ("audit trail") of why and THAT REALLY HELPS months or years down the line when someone comes along and asks "well, why exactly is that picture listed under that species" etc...

Jools

lfinley58 · Post by **lfinley58** » 29 Jan 2007, 15:17

Hi Jools and all.

As more copies of the revision get into folks hands we should be able to have increased communication on the topic. I did a post over the weekend providing an email contact to the Editor of the publication in which it appeared. I will follow your suggestions for providing a reason, or reasons, for suggesting changes to any particular image.

I have pulled a lot of images from the Cat-eLog to go over, but an editing job (which will hopefully be over in two to three weeks) has been taking the major share of my time. Have to make some $$$ in addition to having fun with catfishes.

Lee