Comment on the proposed conservation of Pseudobagrus Bleeker, 1858 (Osteichthyes, BAGRIDAE) (Case 3455)

Publication Type:Journal Article
Year of Publication:2010
Authors:Kottelat, M, Ng, HH
Journal:Bulletin of Zoological Nomenclature
Volume:67
Issue:1
Start Page:68
Pagination:68-71
Date Published:03/2010
Type of Article:Comment
ISSN:0007-5167
Full Text

We are writing to comment on the petition of López et al. for the Commission to use
its plenary power to suppress the siluriform generic name Tachysurus La Cepède
1803. The petition results from our publication clarifying the identity of Tachysurus
(Ng & Kottelat, 2007). The consequences of our neotype designation, as described by
López et al., are not new since we detailed all.
It has been more than a year since this application was published and we had
hoped that this case would be important enough to elicit comments. The fact that no
one has written to support or oppose the petition can be seen as an indication of the
(un)importance of the case. Since no comments have been forthcoming, we explain
below why we do not see the use of Tachysurus instead of Pseudobagrus as a threat
to stability of nomenclature. Once considered in the context of nomenclature of
Asian freshwater fishes, the changes are much less dramatic than suggested by López
et al.
La Cepède (1803) described Tachysurus sinensis from a Chinese painting. The
generic name Tachysurus remained unused until Eigenmann & Eigenmann (1888)
first applied it to the predominantly marine catfishes of the family ARIIDAE.
Tachysurus was used for members of the ARIIDAE for about 30 years (as a senior
subjective synonym of Arius Valenciennes, 1840) until Jordan (1923) raised the
possibility that T. sinensis could refer to a freshwater catfish and not an ariid. Since
then, the usage of Tachysurus for members of the ARIIDAE has been more sporadic,
with both Arius (e.g. Inger & Chin, 1962) and Tachysurus (e.g. Smith, 1945) being
used. Wheeler & Baddokwaya (1981) presented evidence that T. sinensis was not a
member of the ARIIDAE; since then the usage of Tachysurus for ariids has sharply
decreased and is now restricted to non-taxonomic literature (see below).
Referring to Wheeler & Baddokwaya (1981), López et al. (BZN 65: 202–204)
commented that ‘the identity of Tachysurus remained ambiguous as an undetermined
siluriform’ until our designation of a neotype for T. sinensis (in passing, admitting
that we solved the problem). This is not exactly the case. Wheeler & Baddokwaya
(1981) addressed only the problem of whether T. sinensis was an ariid or not, and
having concluded that it was not, they did not bother to explore its actual identity.
With experience of the East Asian Siluriformes, they would have realised that the
figured fish can only belong to the Bagridae.
That T. sinensis was not recognised as a bagrid for a long period was probably
largely due to the lack of access to the figure in the original description. The figure
(reproduced by Wheeler & Baddokwaya, 1981), shows several features (e.g. colorpattern) clearly attributable to the bagrid catfish genus then recognised as Pseudobagrus.
Anyway, the name T. sinensis remained in limbo, variously listed as nomen
dubium or incertae sedis. Nomina dubia and incertae sedes are not meant to be
permanent statuses: their fate is to become valid or invalid. They remain potential
threats for younger valid names and for the sake of stability their identity must be
resolved, the sooner the better. In that aspect Tachysurus is a good example. Had the
identity of T. sinensis been clarified in 1923, it would quickly have reached general
usage. Nobody tried to resolve the taxonomic and nomenclatural status of T. sinensis
until our addressing the problem and solving it by a neotype designation (Ng &
Kottelat, 2007).
The general misapplication of the name has stopped since Wheeler & Baddokwaya’s
(1981) identification of T. sinensis as a catfish not of the family ARIIDAE. Although the
name Tachysurus is still occasionally and mistakenly applied to members of the
ARIIDAE, a search of the Zoological Records Online (conducted on 3 August 2009) for
the period 1981–2009 revealed that Tachysurus has been used for members of the
ARIIDAE only ten times within the last ten years, and always by fisheries scientists or
parasitologists from one country (India). Fisheries literature notoriously may ignore
taxonomic and nomenclatural changes for dozens of years. Should ill will, lack of
information or incompetence be used as a standard to decide on validity of names?
Given the small number of incidences and its restriction to users from a single
country, we feel that this is unlikely to lead to widespread confusion should
Tachysurus remain in use for East Asian bagrid catfishes.
The present generic nomenclature within the Bagridae dates from Jayaram (1968),
who organised East Asian bagrids in five genera (Bagroides, Coreobagrus, Leiocassis,
Pelteobagrus, and Pseudobagrus). Mo (1991) showed that the East Asian species that
Jayaram assigned to Bagroides and Leiocassis were not congeneric with those from
Southeast Asia and Mo assigned them to either Pelteobagrus or Pseudobagrus.
However, Chinese authors still persist in using Leiocassis for some East Asian species
(e.g. Zheng & Dai, 1999; Yu et al., 2009). The assignments of some species keep
shifting between Pseudobagrus, Pelteobagrus and Leiocassis. The notion of a stable
Pseudobagrus as presented by López et al. became so only when Ng & Freyhof (2007)
placed all of the East Asian taxa into a single genus (Pseudobagrus), citing previously
published morphological and molecular evidence. These facts greatly weaken the
argument that conservation of Pseudobagrus would save us from ‘taxonomic
confusion’.
López et al. contend that the usage of Pseudobagrus for the East Asian members
of the Bagridae is widespread, and cite usage in at least 135 papers in 50 years as an
example. This approximates to three papers a year, a very low rate for a genus within
a ‘group that . . . includes species of commercial significance’ and with a large body
of literature. The proposal by López et al. compares unfavorably with the change of
both the generic and specific names of the rainbow trout from Salmo gairdneri to
Oncorhynchus mykiss, which did not cause any significant problem to users and
became established very quickly. The usage of the binomen for the rainbow trout is
considerably more extensive, being cited each year in thousands of scientific,
technical, commercial and popular publications, and mentioned in national and
international legal instruments. The species is the object of a trade worth billions of
dollars annually.The list of 135 references that López et al. provide includes many publications in
Chinese journals, giving the impression of a common usage of the name Pseudobagrus.
The reality is somewhat different. Our experience with Chinese journals is
that binomens are used only in the title, introduction, and/or abstract (and sometimes
in tables and figure/table captions; the latter case only occurs when there are English
translations of the captions) and it is the Chinese name for the species that is used
throughout the text. It was not possible for us to verify if this is true for all of the
non-taxonomic papers in the listed Chinese journals simply because we could not
access them, but it is confirmed in those we could obtain. Also, we do not have the
luxury of investing days in what we consider a sterile diversion from more important
taxonomic research; we do understand, however, that others may not share our
priorities.
As explained in our paper (Ng & Kottelat, 2007), we have been aware of the
nomenclatural problems surrounding Tachysurus for a long time. That the problem
has been mentioned in publications published between Wheeler & Baddokwaya’s
(1981) study and our neotype designation (e.g. Kailola, 2004) indicates that other
ichthyologists are also aware of it. The resolution of the identity of T. sinensis was
made necessary by a checklist of freshwater fishes of southeastern Asia being
prepared by one of us (MK). This led to the discovery of (and need to make decisions
on) about 25 cases of genera of uncertain identity and/or presenting priority conflicts
leading to name changes. It was recognised that most of these name changes would
be annoying but could be avoided only by applications to the Commission. That so
many nomenclatural problems subsist at the genus level, even in taxonomic literature,
indicates how far we are from a stable nomenclature in the covered group and area.
Besides, these are changes for strictly nomenclatural reasons, not reflecting taxonomic
problems; we expect that many more changes at genus level will result from
future taxonomic research. It was decided that submitting about 25 applications
(about equal to the number of applications published in the 2009 volume of BZN!)
would make less sense than submitting applications only for cases of great complexity
or ones in which family group names were involved. (e.g. the Mystus case, which
would have meant changing the names of two families; see BZN 64: 100–102 and
Opinion 2209, BZN 65: 237–238).
Regardless of the consequences, the Tachysurus case is quite trivial. There were two
possible solutions: (1) designation of a neotype or (2) suppression of the names under
the plenary power of the Commission. Our decision to designate a neotype for T.
sinensis was taken after consultations with colleagues. The neotype designation
allows an immediate decision without involving the Commission and the resulting
delays, printing costs, work load, etc.; this is the solution we chose. We regret that the
application by López et al. has now postponed a stabilisation of the names for this
genus by several years and generated expense and work. Our decision was bolstered
by the relative unimportance of the case, as discussed above.
We wish to comment on one of López et al.’s concluding sentences that ‘the
original description of T. sinensis . . . is unlikely ever to yield a satisfactory
association with a recognised group’. That an original description be deficient is not
a problem in itself. The association of a name to a taxon is made by the type, not by
the description, and this was exactly the purpose of the neotype designation that we
made.In conclusion, we suggest that the Commission should not use its plenary power
for this relatively minor case, which has been unambiguously cleared by the simple
application of the Code.
Additional references
Eigenmann, C.H. & Eigenmann, R.S. 1888. Preliminary notes on South American Nematognathi.
I. Proceedings of the California Academy of Sciences (Series 2), 1: 119–172.
Inger, R.F. & Chin, P.K. 1962. The fresh-water fishes of North Borneo. Fieldiana Zoology, 45:
1–268.
Jayaram, K.C. 1968. Contributions to the study of bagrid fishes (Siluroidea: Bagridae). 3. A
systematic account of the Japanese, Chinese, Malayan and Indonesian genera. Treubia,
27: 287–386.
Jordan, D. S. 1923. A classification of fishes including families and genera as far as known.
Stanford University Publications, University Series, Biological Sciences, 3: 77–243, i–x.
Kailola, P.J. 2004. A phylogenetic exploration of the catfish family Ariidae (Otophysi:
Siluriformes). The Beagle, Records of the Museums and Art Galleries of the Northern
Territory, 20: 87–166.
Kottelat, M. & Ng, H.H. 2007. Case 3382. Mystus Scopoli, 1777 (Osteichthyes, Siluriformes):
proposed conservation of usage by designation of Bagrus halepensis Valenciennes in
Cuvier & Valenciennes, 1840 as the type species. Bulletin of Zoological Nomenclature, 64:
100–102.
Mo, T.-P. 1991. Anatomy, relationships and systematics of the Bagridae (Teleostei: Siluroidei)
with a hypothesis of siluroid phylogeny. Theses Zoologicae, 17: 1–216.
Ng, H.H. & Freyhof, J. 2007. Pseudobagrus nubilosus, a new species of catfish from central
Vietnam (Teleostei: Bagridae), with notes on the validity of Pelteobagrus and Pseudobagrus.
Ichthyological Exploration of Freshwaters, 18: 9–16.
Smith, H.M. 1945. The fresh-water fishes of Siam, or Thailand. Bulletin of the United States
National Museum, 188: i–xi, 1–622.
Yu, Y.-Y., Xiao, M.-S., Chen, L. & Yang, G. 2009. Isolation and characterization of
microsatellite loci in the longsnout catfish (Leiocassis longirostris). Aquaculture Research,
40: 246–248.
Zheng, B.-S. & Dai, D.-Y. 1999. Bagridae. Pp. 35–74 in Chu, X.-L., Zheng, B.-S. Dai, D.-Y.
et al. (Eds.), Fauna Sinica. Osteichthyes. Siluriformes. Science Press, Beijing.

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