Mystus dibrugarensis

[Shovelnose]

Mystus dibrugarensis is currently listed as a synonym of

Mystus montanus

in the cat-elog. It is a valid species and needs to be added to the cat-elog. I will do the same on confirmation.

[MatsP]

It would seem that the species in CoF is considered a synonym. I see that Steven Grant ("The.Dark.One") doesn't necessarily agree, but we do follow CoF unless you have a good reason for why we shouldn't.

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Mats

[Shovelnose]

Hey Mats

I was also referring to this : http://www.iucnredlist.org/apps/redlist ... s/174492/0.

[MatsP]

The problem with determining "what is a species, and what is a synonym" is that you really have to decide to follow one source - otherwise you are constantly changing things around.

This is my opinion, I'm happy to have a discussion where others join in.

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Mats

[Shovelnose]

How does CoF work??? Do they only follow literature or do they indulge in examining specimens too??? I ask because I am very sure both the references I have checked with have examined the above mentioned species in great detail.

While I definitely agree that following a single source is best to avoid confusion, I think it is also good to check with references who have had a better opportunity to work with a particular species.

Ps : I am trying to source a pic of this species. This might clarify things better.

[MatsP]

CoF follows literature, and as far as I know don't actually examine species.

However, if someone is able to determine that they are different species, then I would think that this should be published in a paper somewhere - then it's a case of getting that accepted of course.

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Mats

[Shovelnose]

True. I don't know of any paper that raised this to species level. Lets see if HH or Steve chip in with their opinions.

[RickE]

Is this relevant?: http://www.scotcat.com/articles/article65.htm

Mystus dibrugarensis (Chaudhuri, 1913)

(Click thumbnail for image)

See image of the holotype, which came from Dibrugarh, Assam, India and measures 6.8 cm total length. Colour and pattern described as: “Head grey, dorsal side dark brown, body brownish. The membranous covering of the air bladder behind the gill openings is black, and a black line from above this membrane extends through the middle of the side to the middle of the root of the caudal fin, ending in a black circular blotch. The barbels are black, except the inner mandibular, which, with the fins, is dull white.”
This species was originally described as Macrones montanus var. dibrugarensis. Contrary to Jayaram (1954) and subsequent authors it is not a junior synonym of Mystus montanus (Jerdon, 1849). M. montanus was described by Jerdon from the Kabini River of the Kaveri (or Cauvery) system in south western India as: “greenish above and on the fins; yellow on the cheeks and beneath.” There is no mention of any stripe(s) on the body, or semi-ocellus. Jayaram & Sanyal (2003) give information on M. montanus from further south than the type locality and show that whilst in life it is silvery grey with light yellowish bands along the sides, it can exhibit greenish bands along the sides with a dark spot at the base of the caudal fin, and a dark mark near the tympanum. In M. montanus the caudal lobes are shaped differently, the adipose fin appears to have a longer base, and the body and fin patterns differ. In my opinion the different zoogeography should be taken into account, M. dibrugarensis being from the upper Brahmaputra River in north eastern India.
M. dibrugarensis differs from M. canarensis by having the supraoccipital process raised, long, and touching the basal bones of the dorsal fin (versus not raised, very short, and not touching); body not elongated; caudal fin lobes being equal (versus upper lobe being longer than lower lobe). Also see notes on M. malabaricus, M. pulcher and M. rufescens.

[Shovelnose]

Hey Rick,

That is Steve's (The Dark One) article Mats was referring to in his first reply.

[MatsP]

Yes, and I think the key here is that the CatChat (where it was originally published) isn't a highly attributed publication, so the Checklist of Catfishes for example, isn't accepting the findings.

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Mats

[Shovelnose]

http://zsi.gov.in/checklist/Native%20fr ... 0India.pdf

This is the latest paper I know of that lists M.dibrugarensis as a valid species. I have gotten a pic with the collection locality. I will start a separate thread for that.

[MatsP]

Maybe you should take the point up with Bill Eschmeyer (who looks after CoF).

--
Mats

[The.Dark.One]

My articles wont be followed scientifically (regardless of whether their viewpoints are right or wrong, carcio for example) as they are generally not based on physical examination of specimens, nor published in peer reviewed journals so PC is better following other sources.

Having said that Vishwanath, Lakra, & Sarkar 2007 agree that dibrugarensis is valid:

Fishes of North East India. National Bureau of Fish Genetics Resources, Lucknow.

[lfinley58]

Hi all,

I don't think that it has been mentioned yet but Silurus (HH) is listed as the Assesor on the IUCN piece on the Mystus in question. That would indicate to me that he agrees with the designation.

Lee F.

[Jools]

Hi all,

I don't think that it has been mentioned yet but Silurus (HH) is listed as the Assesor on the IUCN piece on the Mystus in question. That would indicate to me that he agrees with the designation.

Lee F.

Indeed - a very good point.

Jools

[MatsP]

Lee, that is indeed a good point.

--
Mats

[Shovelnose]

Silurus (HH) is listed as the Assesor on the IUCN piece on the Mystus in question.

Exactly why I quoted this as a reference. It didn't strike me that this might need pointing out.

Edit : I guess I can go ahead and add this species now???

[Shane]

but we do follow CoF unless you have a good reason for why we shouldn't.

Since when did CoF become the template for the cat-elog? And why are we telling well intentioned, knowledgeable contributors to "take it up with Bill Eschmeyer"? Unsatisfactory all around.

-Shane

[Silurus]

People often miss the point about the CoF's intended usage. It is a nomenclatural database (at least this is what I think Bill Eschmeyer intended it to be), not a taxonomic one. Given its coverage, it is often used as the latter (FishBase being the most egregious offender).

[MatsP]

People often miss the point about the CoF's intended usage. It is a nomenclatural database (at least this is what I think Bill Eschmeyer intended it to be), not a taxonomic one. Given its coverage, it is often used as the latter (FishBase being the most egregious offender).

So the difference is that it's showing what the current name is [accoding to Eschmeyer] for Species X, rather than telling us which species are valid? Or am I misunderstanding things?

Either way, Silurus, do you have an opinion on the original subject? It's implied above that if you didn't actually write the entry in IUCN, at least you approved it...

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Mats

[Jools]

This might have been one of those topics to be replied to too quickly as we have a leading expert on this genus "on the staff" and a quick "I'll wait for Silurus to comment" post or two might have served the OP better and certainly would have saved a lot of keyboard taps and reading time.

It has thrown up the following key point.

The problem with determining "what is a species, and what is a synonym" is that you really have to decide to follow one source - otherwise you are constantly changing things around.

Do you mean follow one source on a per species or per genus basis or follow one source for the entire cat-elog (and by extension AR). If the latter I think Shane has a question for you!

Jools

[MatsP]

It has been my understanding that unless there is good reason for otherwise, we follof CoF. I'm probably missing some important (but obvious to everyone else) point here...

--
Mats

[The.Dark.One]

To quote the IUCN entry (which I assume is by Silurus?):

"Mystus dibrugarensis was described from Dibrugarh, Assam (which is situated along the Brahmaputra River) as a subspecies of M. montanus by Chaudhuri (1913). Although it is regarded as a junior synonym of M. montanus in many accounts (e.g. Jayaram and Sanyal 2003; Ferraris 2007), the latter species is restricted to southern India (in the Cauvery River drainage) and differs from M. dibrugarensis in having a longer adipose-fin base and a more diffuse spot on the caudal peduncle."

[The.Dark.One]

Catalog of Fishes also list it as valid now anyway.

[MatsP]

So I guess someone told Bill about "new findings", or it was just about to be updated anyways - there is a reference to a 2011 paper as well as yours.

--
Mats

[The.Dark.One]

So I guess someone told Bill about "new findings", or it was just about to be updated anyways - there is a reference to a 2011 paper as well as yours.

--
Mats

As Silurus has said it is a nomenclatural and reference database. The final entry on validity of a taxon is just based on the editors' take on prevailing views (apart from a few situations like objective synonyms etc). As a work in 2011 specifically on Mystus has declared it valid as well they appear to have gone with it. You shouldn't rely 100% on COF or Fishbase's validity entry. In 1999 (description of Mystus canarensis) I said it was a valid species. It didn't take a genius (of which I clearly am not) to see that a species naturally occurring in north eastern India would be the same as one endemic to the south of India, particularly when there are physical differences too!

[MatsP]

So what method do we use to determine if something is or isn't a valid species? Most importantly, how do we know what the prevailing scientific community thinks?

I'm sure there are quite a lot of examples where we, as hobbyists, can point out that "this one is quite different from that one", where there is a single scientific name - and probably the odd case of "they are almost identical" but given two differen species names. So whilst it may "not take a genius to say it's a different species", I'm not sure it's as simple as that.

I mean a method that works "most of the time", not saying it must work ALL the time [I don't think there is one method that works all the time, beyond hiring a whole bunch of good scientists - and they probably wouldn't agree most of the time anyways].

Or is there no "rule" for this, and we just do what "feels right at the time"?

I may have been wrong in the way I approached the subject in the first place, but I think it would be good to discuss by what method we determine what should and shouldn't be added as a new species.

--
Mats

[The.Dark.One]

Unless a species is permanently invalid for nomenclatural reasons (rare) then validity of species is down to opinion, regardless of how well (or not) this has been argued by the person working on it. That is why some species go in and out of validity. Some authors class them as valid, some don't. There is no absolute right or wrong answer, it is just down to opinion and how well someone can scientifically argue it.

COF and Fishbase look at what work has been done and will either go with the majority, pick the latest work, pick one that is more scientific or in depth on the species in question, or even on how well regarded the author's work is. Take dibrugarensis for example:

Almost every piece of published work on Mystus classed it as a synonym of montanus. In 1999 I stated why (without examining any material of dibrugarensis but using the figures and information in the original descriptions) it was valid. This was in a peer reviewed journal but not one that is highly regarded. I am not a scientist (although that doesn't stop one from doing it - although in hindsight perhaps it should have stopped me, but that's another story). All those factors meant that the opinion was not followed in other works so COF and Fishbase followed the majority. However, because Indian authors are stating the same thing, and recently, and notably in a work on Mystus, COF has gone with it being valid.

So all I would say is COF and Fishbase are not the arbitrators of the validity of species. With everything else you need to make your own mind up. How you do that and what opinions you follow is entirely up to you. In terms of what should be done with the clog then I would suggest that a discussion takes place, especially when you have a bagrid expert on the books in the shape of Silurus.

[MatsP]

In terms of what should be done with the clog then I would suggest that a discussion takes place, especially when you have a bagrid expert on the books in the shape of Silurus.

Who, perhaps understandably, as I can be a right idiot at times and offer opinions where none was required, has not offered ANY suggestion as to this subject, other than state that CoF is "not a taxonomic reference, but a nomenclature reference" or some such - and I'm too much of an amateur to understand the difference between those two terms.

In summary, I'm still confused... (And should probably shut up before I'm even deeper in this hole that I'm digging...)

--
Mats

[The.Dark.One]

"not a taxonomic reference, but a nomenclature reference" or some such - and I'm too much of an amateur to understand the difference between those two terms.

Taxonomy is about ordering, classifying, naming species. So COF isn't actually doing that, it is reporting on the effect on the scientific names of the efforts of others who are doing it - the effect on the nomenclature of the species/ genus. Meaning the correct formation and listing of names. So, for example, a database of species/genera described that provides the original spelling(s), who described it, when, what combination it was used in terms of the genus, what rank, e.g. subspecies, type species designations, whether the name is available scientifically, what the current prevailing genus/species combination is, and the impact of that on the name (e.g. like when the species suffix sometimes changes because of a change of genus) - but also the the work in which it was described, the type locality, where the specimens are etc. It does exactly what it says on the tin: it is a catalogue - not a worldwide arbitrator on what is a valid taxon.