Otopharynx walteri - was 5 New Metriaclima Species

New cichlid species and taxonomy
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Mark Smith
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Otopharynx walteri - was 5 New Metriaclima Species

Post by Mark Smith » Wed May 08, 2013 8:55 am

Please allow me to steer the subject away for a moment: With all the very similar looking Metriaclima/Maylandia species that have been formally described, how is it that Otopharynx walteri is now considered a color variant of Otopharynx lithobates? O. walteri is a sound, validly described species that should not have been synonymized with O. lithobates.

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Philippe Burnel
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Re: 5 New Metriaclima Species

Post by Philippe Burnel » Wed May 08, 2013 9:01 am

I agree too

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Mark Smith » Wed May 08, 2013 9:45 am

...as well as Benthochromis horii incorrectly being considered B. tricoti

...as well as Xenotilapia sp. "Flourescent Green" incorrectly being considered X. nasus

...as well as Neolamprologus sp. "Ventralis Kasanga" incorrectly being considered N. ventralis

...as well as Melanochromis xanthodigma incorrectly being considered M. baliodigma

all within Cichlidae.com.

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Philippe Burnel
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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Philippe Burnel » Wed May 08, 2013 11:06 am

I think that for tricoti/horri the story is not finished and will proove that there is really only one species.

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Pete B » Wed May 08, 2013 5:17 pm

What happens when there is disagreement over species classification or naming?

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Philippe Burnel » Thu May 09, 2013 2:18 am

Guys use the name they believe to be suitable.
That's exactly what happens with Maylandi/Metriaclima

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Willem Heijns » Thu May 09, 2013 3:03 am

Philippe:
You are mixing taxonomy and nomenclature here. Believing two taxa are the same or not is a matter of taxonomy. Everyone can have his/her opiníon on that. That is completely different from nomenclature, where rules have to be obeyed.
Slàinte mhath!

Uilleam

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Philippe Burnel
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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Philippe Burnel » Thu May 09, 2013 4:21 am

Willem Heijns wrote:Philippe:
Believing two taxa are the same or not is a matter of taxonomy. Everyone can have his/her opiníon on that.
I thought it was the question !

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Thomas Andersen » Thu May 09, 2013 9:24 am

Mark Smith wrote:
...as well as Xenotilapia sp. "Flourescent Green" incorrectly being considered X. nasus
What is "correct" then? Any solid evidence of the opposite you wanna share with the rest of us?

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Mark Smith » Thu May 09, 2013 10:22 am

Hi Thomas

Just wanting to stimulate some conversation here, thanks for asking.

Of course, referring to the photo of X. nasus of Fishbase is my starting point. X. nasus is a more elongated fish, with a more slender caudal peduncle than X. sp. "Fourescent Green". Also, the eye of X. nasus appears to be larger, and the space from the front of the eye to the tip of the snout is longer than in X. sp. "Flourescent Green", especially when compared to the photo by Konings in Cichlid News Magazine July 2012 issue, page 31 of a specimen from Gombe, that looks much more blunt when contrasted with the photo by Ammelrooy on page 32. The dorsal fin pattern in X. nasus is subtantially different than in X. sp. "Flourescent Green" as well as caudal fin pattern. In X. nasus, the bottom edge of the white horizontal stripe on the dorsal fin runs down the middle of the height of the dorsal fin, whereas in X. sp. "Flourescent Green" the white horizontal stripe in in the upper 1/4 to 1/3 of the dorsal fin, along with yellow spotting below. The anal fin appears to be much shorter lengthwise (fewer anal fin rays?) than in X. sp. "Flourescent Green"Lastly, X. nasus has a bulb-like snout tip, far more obvious than in X. sp. Flourescent Green". Also, in the July 2012 issue of Cichlid News Magazine, page 32, you said: "The differences can easily be explained in other ways, e.g. because of ecological reasons, as the higher built body of X. sp. "Flourescent Green" could be due to an abundance of food;" there is really no way to test such a theory out. The amount of food consumedwill vary depending on the time of year, and there is truly no way that less food would indicate a shallower body depth and more food indicate a deeper body depth. In addition, it has not yet been disproven that both species may live sympatrically, particularly in the northern parts of the lake, as it is hard to spend much time at such depths observing. With all that, it is good to be mindful of just how many species from the lake can look similar to each other, and yet are distinct species. There are greater differences between these two Xenotilapia species than there are between Neolamprologus caudopunctatus and N. leloupi, N. chitamwebwai and N. falcicula, Haplotaxodon microlepis and H. trifasciatus, Simochromis babaulti and S. pleurospilus, various Tropheus and Petrochromis species, etc, etc. Something to carefully consider rather than gravitating towards a more "lumping" direction. Of course, the best direction to go with is to scientifically examine X. sp. "Flourescent Green" from throughout the lake and see if they keys out to X. nasus.

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by SergeS » Fri May 10, 2013 5:05 pm

What a weird coincidence that you mention this, Mark! I ran across O. walteri on a stocklist of a German importer earlier today, and was thinking about adding it to my main tank. But would I be adding O. walteri or O. lithobates? Fishbase also calls O. walteri a junior synonym of O. lithobates. Is O. walteri in reality a geographical variety of O. lithobates? Or is really different? O. lithobates is already quite variable in terms of colour (white blaze, yellow blaze, all blue, maybe some more).

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Mark Smith » Fri May 10, 2013 5:47 pm

Hi Serges

Good question. I can only guess that since they are using the name O. walteri, that it is the true O. walteri. I maintain that O. walteri is a distinct species from O. lithobates for several reasons. The recent paper describing new Stigmatochromis by Konings and others, (Stauffer, Jay Richard Jr. & R.M. Cleaver-Yoder & A. Konings. 2011. "Two new species of Stigmatochromis (Teleostei: Cichlidae) from Lake Malaŵi, Africa". Proceedings of the Biological Society of Washington. v. 124(n. 3), pp. 212-222) posited the theory/recommendation that O. walteri is a junior synomym of O. lithobates, essentially making null and void Konings original description of O. walteri many years previous (Konings, Ad. 1990. "Descriptions of Six New Malawi Cichlids". Tropical Fish Hobbyist Magazine. 38 (11): pp. 110-129). Fishbase is just going by what was recommended in the the more recently published paper, and not the latter. Since the publication of the latter paper, several people have promoted the idea that O. walteri is a variant of O. lithobates.

Appearance wise, O. walteri is a deeper bodied fish, with different melanin pattern on the body that in O. lithobates. Also, the snout of O. walteri is more pointed/elongated than in O. lithobates. Dorsal fin coloration is also different in O. walteri than in O. lithobates. O. walteri also has a larger mouth and a shorter caudal peduncle. O. walteri also grows to a larger size than O. lithobates (in the wild, that is).

Behaviorally, O. walteri is a secretive species and only occurs at Nakantenga and part of Maleri Island, showing no geographical color variation. O. lithobates occurs in Cape MaClear National Park, and may even occur sympatrically with O. walteri at Maleri Island? The O. lithobates I encountered at various places in Cape MaClear National Park, were not secretive at all. In fact, each time I would come up to their territory, the dominant males would always swim up to me to investigate what I was. This sort of behavior is not seen in O. walteri, as it is very secretive/shy. It would be interesting to compare/contrast eggs sizes between both species, as well as auditory sounds given off between them both, to see if there are additional differences.

So, I think O. walteri is a valid species, and also much less commonly available in the hobby than O. lithobates. I would get them if you have the opportunity.

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by SergeS » Sat May 11, 2013 5:09 am

These arguments make sense, the physical differences between the two seem quite considerable. There are plenty of other fish, considered to be separate species, with far less differences than these two! I'll have to read up on the arguments on why O. lithobates and O. walteri should not be considered separate species then :) Oliver probably has something on his site on this, he's one of the people who believe O. walteri to be a variant of O. lithobates.

In the aquarium, I have the same experiences with O. lithobates as you apparently did in the wild. I kept some a few years ago, and although it's not extremely agressive, it surely is very visible in the tank and definitely not shy. It swims a lot and is very curious, and, similar to many Placidochromis spp., they appear to be attracted by swirling sand and detris.

If O. walteri is more secretive, this could also indicate it has different feeding behaviour, is this correct? Is it more predatory maybe? The shape of the fish and the head would indicate that as well.

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by SergeS » Mon May 13, 2013 7:53 am

I found M. Oliver's comments on O. walteri as a separate species (here: http://www.malawicichlids.com/mw08076.htm). And as he makes sense as well, I have no idea what to believe anymore, but I did read that Ad Konings indeed saw "O. walteri" hunting small fish, so my conclusion re. their secretive / feeding behaviour wasn't that stupid it seems :D

Maybe we will just have to live with the idea that some questions will not be answered in any of our livetimes :lol:

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Mark Smith » Mon May 13, 2013 8:44 am

There are sufficient reasons in Konings official description of O. walteri to justify it being a distinct species.

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Re: Otopharynx walteri - was 5 New Metriaclima Species

Post by Mark Smith » Mon Jun 10, 2013 5:02 pm

Forgot another one...Iodotropheus declivitas synonymized with I. sprengerae.

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