Pseudotropheus or Melanochromis perspicax Trewavas 1935

[Darrell Ullisch]

Well, I'm wondering if anyone can add to the information I've gotten while trying to research the correct name of this fish.

I have found that perspicax, which is listed as a Pseudotropheus here in the CRC catalogue and in the Aqualog book, is listed as a Melanochromis under Fishbase and the Catalogue of Fishes. In fact, the CRC catalogue actually pointed me in the right direction, as it mentions that the fish was originally described as Melanochromis perspicax Trewavas 1935. Many of the fish in that genus were placed in Pseudotropheus for a time; when I first had auratus in 1975, it was known as a Pseudotropheus.

Many sources still list perspicax as a Pseudotropheus, despite the papers in 1983-84 that declared Melanochromis Trewavas 1935 to be a valid genus; and a specific listing in 1991 by Marechal in Daget, et al, specifically places perspicax back into Melanochromis. While that paper is mentioned in the CoF, the usage of Pseudotropheus prior to that is not, despite the fact that it was cited in that '91 publication, according to Fishbase. So, apparently Pseudotropheus perspicax does not show up in Eschmeyer's list because there was no formal change to Pseudotropheus for that individual species, even though Melanochromis was, for a time, considered a synonym of Pseudotropheus. Or, at least I think it was - no reference for that, either.

I think I'm going back to strictly New World Cichlids. Even Kullander didn't mess those up as badly as these people have done to the Malawian Genera. (Well, maybe he did.) It's almost enough for me to understand the folks who say, "That's what I bought it as!" Almost.

[Mark Smith]

Hi Darrell

Great to see you taking the time to research these names. A word of caution, though, as you indicate you have gone to Fishbase for information. Be careful with the information on Fishbase. Often times, the information on that site is completely erroneous, or made up. The photographs that accompany some commonly known cichlid species on this site are also incorrectly identified. And, there are still newly described cichlid species from nearly one year ago that have not yet been added to the site.

My favorite error was when they included a photo of infamous hybrid Red Parrot monstrosity, identifying it as Hoplarchus psittacus. Thankfully, they have since removed the photo and put in the correct image.

[Darrell Ullisch]

Oh, I'm well aware of the problems with Fishbase (their Killifish are worse than Cichlids!), however, in this particular instance, I'm also looking at the references at Cal Academy's Catalogue of Fishes, which is updated more regularly than Fishbase, and I've looked at a couple of books, as well. It's a matter of judging validity from the information given, and after 40 years of studying the fish I keep, I've gotten pretty good at it.

In this particular instance I see papers that place the fish in one genus, while several people are using one that was, at best, a temporary placement according to the published works. Because I generally do not keep Mbuna, I do not have the connections to know if there is a more recent publication than the 1991 list. That is the reason for asking here, where I am reasonably sure there are people who do have many of those connections.

[Michael Oliver]

Hi Darrell,

Yes, as you wrote, the fish was originally described as Melanochromis perspicax by Trewavas in her 1935 "Synopsis." She had only a single specimen, which I have seen and photographed. Trewavas said nothing of its coloration; my photo shows it to be a plain dark fish with no discernible color pattern. The species has never been revised, so far as I know.

However, Ribbink and colleagues (1983: 194) discussed a creature they called "Pseudotropheus cf. Melanochromis perspicax," which they did not illustrate. They said the fish going under their name is "a small, aggressive, lithophilous species of the shallows of the north-western lake," which they found at Ruarwe and Chilumba. (Note that Chilumba is the current name for the town known as Deep Bay in Trewavas's day, and that Deep Bay is the type locality of Melanochromis perspicax.) Ribbink et al. give a fairly detailed color description of their "Pseudotropheus cf. Melanochromis perspicax," noting among other points that males at Chilumba have "Body powder-blue with faint grey barring [emphasis mine] and yellow-gold chest." They go on to note, "Superficially this species resembles Melanochromis perspicax, and may prove to be conspecific. By virtue of its aggressive behaviour and its lack of longitudinal barring [emphasis again added by me; longitudinal or horizontal "barring" is usually called stripes rather than bars, but the meaning is clear], it has been placed in the Pseudotropheus 'aggressive' species-group for the time being."

If Ribbink et al. are correct in their suggestion that their "Pseudotropheus cf. Melanochromis perspicax" is perhaps the same species as Trewavas's Melanochromis perspicax, then Melanochromis perspicax should be removed from Melanochromis because it lacks the diagnostic sexually dimorphic horizontal stripes of that genus. This is also implied by Ribbink et al. referring to their similar and perhaps conspecific species as a species of Pseudotropheus. Notably, Konings has also illustrated a couple of unstriped, vertically barred creatures as Pseudotropheus perspicax. But, I would stress that the holotype of Melanochromis perspicax has never been revised, nor adequately described, and that the melanic color pattern of the holotype in life is unknown.

I, for one, think that Pseudotropheus perspicax is the best combination for Trewavas's species, on the available evidence, and pending further study by some brave taxonomist; and that is how I have long listed it on my Mbuna checklist (http://malawicichlids.com/mw07000.htm#pseud3).

[Darrell Ullisch]

I'd say you are making a heck of a lot of assumptions.

1. you are assuming that a dark, preserved specimen is the same as a live, patterned fish because they were apparently collected in the same area. Just curious, how many other species of Mbuna are known from that region, and how detailed has the sampling been?

2. Because Ribbink, et.al., say the fish resembles perspicax, and may be conspecific, you are assuming that it is the same fish. My bolding. How many already described species are similar to that specimen? And there are a number of undescribed species in that "Ps. aggressive" complex, are there not?

3. you are assuming that you can assign the species to another genus based on the above assumptions, rather than examining the specimens involved, taking measurements, and following the proper procedure to verify that they are the same fish; then actually going to the trouble to write a paper stating your case. In other words, being the "brave taxonomist" instead of assuming that one will come along. Ribbink is NOT stating your case, they are talking about their own fish, which they, at least, did not assume to be the same as perspicax.

4. You are assuming that Dr. Ethelwynn Trewavas couldn't figure out that a specimen didn't belong to a genus she described.

You are probably correct that the fish currently available under the species name perspicax is a Pseudotropheus. However, you have shown me no evidence that it is the same species as Melanochromis perspicax, only that it might be. There is no authority allowing you to call it by that name while waiting for someone else to do the research. Shortcuts are not in the Code. If by some chance it turns out that the fish you are calling Ps. perspicax is not the same as the specimen described as Melanochromis perspicax, you will have created a nomen nudum.

At this point, we don't even really know if the species described as Melanochromis perspicax is in the hobby. The fish you are calling Pseudotropheus perspicax is Pseudotropheus cf. Melanochromis perspicax, as labelled by Ribbink, et al, the last ones to do any actual research on the species. It should remain so until your "brave taxonomist" shows up and puts something on paper.

[Michael Oliver]

I'd say you are making a heck of a lot of assumptions.

Easy there, chief! I didn't express most of the opinions you seem to be attributing to me. There are not many assumptions in what I wrote.

One assumption I did make was that you were sincerely looking for information to decide the current status of the fish initially described as Melanochromis perspicax. All I tried to do was set out some details that I thought you might not know and that I hoped might be helpful or interesting. I wasn't trying to generate controversy or tell you what to think.

1. you are assuming that a dark, preserved specimen is the same as a live, patterned fish because they were apparently collected in the same area....

On the contrary, I carefully stated that the holotype is "a plain dark fish with no discernible color pattern" and even stressed that "the melanic color pattern of the holotype in life is unknown." The strongest link I made between this dead holotype and living fishes was that "If Ribbink et al. are correct in their suggestion that their "Pseudotropheus cf. Melanochromis perspicax" is perhaps the same species as Trewavas's Melanochromis perspicax, then M. perspicax should be removed from Melanochromis because it lacks the diagnostic sexually dimorphic horizontal stripes of that genus." "If" signifies uncertainty, not assumption. I did make a separate point of mentioning that the M. perspicax holotype came from the same locality as Ribbink et al.'s "Pseudotropheus cf. Melanochromis perspicax," because this is obviously germane to an eventual judgment about whether the latter fish could be conspecific with M. perspicax. That's all.

2. Because Ribbink, et.al., say the fish resembles perspicax, and may be conspecific, you are assuming that it is the same fish....

No, Darrell, I am not.

3. you are assuming that you can assign the species to another genus based on the above assumptions....

Mostly, I was pointing out that Ribbink et al. took a species that they said "Superficially ... resembles Melanochromis perspicax, and may prove to be conspecific" and that they assigned that possibly conspecific species to Pseudotropheus. Their point, not mine; I just cited it.

4. You are assuming that Dr. Ethelwynn Trewavas couldn't figure out that a specimen didn't belong to a genus she described.

Not an assumption of mine. I have great respect for what she achieved in advancing cichlid taxonomy, so long ago, working initially with only preserved material. The fact is, though, understandings of the limits of genera change, and more than 70 years has passed since ET's minimal original characterization of Melanochromis. It does not reflect badly on her that some species are no longer classified in the same genus where she described them; usually it means our knowledge has advanced. I'm confident that she would agree (but, of course, I can't prove it).

However, you have shown me no evidence that it is the same species as Melanochromis perspicax, only that it might be.

Agreed; that's all I tried to accomplish.

If by some chance it turns out that the fish you are calling Ps. perspicax is not the same as the specimen described as Melanochromis perspicax, you will have created a nomen nudum.

Not so. Only a new name (new species, new genus, new family) can be a nomen nudum; the term is not about novel combinations.

Respectfully,

[Darrell Ullisch]

First, my apologies; I asked why some people were using Pseudotropheus perspicax and you gave me an explanation. I should have first thanked you for that before launching into a critique of the process!

Second, I'm not saying that the Ribbink's Ps. cf. M. perspicax isn't the same as Trewavas' M. perspicax. It is very likely that you are correct that they are. However, there is nothing in the information you gave me that positively ties the two together within the rules of the Code; and without further investigation, you cannot use the name Pseudotropheus perspicax for any living fish without having made at least a couple of the assumptions I listed. You may want to call it a "leap of logic"; others might call it "jumping to conclusions". That's why the terms cf. and aff. exist, to designate a relationship that has not yet been solidified. In this particular instance, even you have admitted that it has not.

Perhaps my extreme caution in such a situation is the result of conversations with Dr. Stan Weitzman. He is very old school on taxonomy, but his knowledge of the subject is light years beyond any other taxonomist I've met. The popularity of Cichlidae has produced a record number of amateur taxonomists, and with more amateurs you will get more, um, "variation in the reliability" of supposedly assigned names. There is also the tendency of excited hobbyists to jump on a new or changed name, even before it has been properly vetted (Spelling?). Having lived through such problems in Killifish and Characiforms, I will continue to err on the side of caution.

Again, Thank You for taking the time to post the information. From this point, what we will do with it has to be decided elsewhere, by a group working on a project. Again, I'm seriously thinking about removing my overly large nose from the African mess and sticking with the New World mess!

[Rico Morgenstern]

there is nothing in the information you gave me that positively ties the two together within the rules of the Code

Darrell, I don’t think that you will find any rule which would affect the limits (or the subsequent identification) of a species or any other taxon, but rather provides merely the name of such a taxon. If someone is of the opinion that certain specimens are assignable to a named species and does use that name, or if a species is placed in another genus than originally described, this is not a violation of the code. It is only the quality of the arguments for taking such a step, that will lead subsequent workers to regard the provided evidence as sufficient or not. This is the reason why sometimes several names are in use for one and the same species.

Not an assumption of mine. I have great respect for what she achieved in advancing cichlid taxonomy, so long ago, working initially with only preserved material. The fact is, though, understandings of the limits of genera change, and more than 70 years has passed since ET's minimal original characterization of Melanochromis. It does not reflect badly on her that some species are no longer classified in the same genus where she described them; usually it means our knowledge has advanced. I'm confident that she would agree (but, of course, I can't prove it).

Regarding the generic placement of perspicax, there is little to add to Michael Oliver's comments. Trewavas herself has given a rediagnosis of Melanochromis in 1984 (full text pdf available from Michael Oliver's website: http://malawicichlids.com/trewavas_1984a.pdf), which is mainly based on color characters. Although no list of included species was given, it is certainly not possible to include perspicax (even when restricted to the holotype) in that altered concept of the genus. Therefore it would seem to be the best solution to place this species provisionally in the "catch-all" genus Pseudotropheus, until a thorough genus level revision of the entire Mbuna group has been carried out.

RM