Conspectus cobitidum - Raffles Museum of Biodiversity Research

Loaches, fishes of the suborder Cobitoidei, are small benthic
fishes known throughout Eurasia, with two named species
in Africa (Morocco and Ethiopia). Most of them inhabit rivers
and streams in hilly areas but they are also known from
streams in rainforest, in the black waters of peat swamp forests,
or in oases (in the Taklamakan Desert). Many of them
are specialised cave fishes, others inhabit rapids and waterfalls.
The fishes reported from the highest altitude in Asia
are loaches (Triplophysa stolickai at 5200 masl, in hot springs
near Lungmu Co [lake], Ngari County in western Tibet
[34°37'N 80°28'E]; Zhu, 1981: 1063); those reported from
the lowest altitude are also loaches (Triplophysa zhaoi in
swamps of the Lükqün oasis, about 50 m below sea level in
the Turpan depression, Xinjiang, China).
The suborder Cobitoidei derives its name from Cobitis, a
genus established by Linnaeus (1758). This name has an old
history. It first appears as κωβτις in Aristotle's Περ ζων
στοραζ for small fishes that bury in the bottom (Aristotle,
ca. 343 BC; first printed edition in 1476, Historia animalium,
Inquiries on animals, book VI, chapter XIV). Cobitis
means 'like the gudgeon' (κωβιζ). The word was first transcribed
in the Latin alphabet by Rondelet (1555) who used
it for three small fishes identifiable as today's Cobitis taenia,
Barbatula barbatula, and, apparently, Alburnus alburnus.
The name was then used by classical authors like Gesner,
Aldrovandi, Jonston and Willughby. Cobitis is the second
genus in Artedi's system (1738), who also added Misgurnus
fossilis. As Artedi's system was adopted by Linnaeus (1758),
Cobitis entered formal zoological nomenclature.
Work on this checklist began around 1980 when I became
interested in the taxonomy and ecology of Southeast Asian
loaches. On 10 November 2012 the superfamily includes
1043 valid species, out of 1499 nominal species (valid species
plus all their synonyms, emendations, nomina nuda and
some incorrect subsequent spelling occasionally used). They
are presently placed in 111 genera (out of 185 nominal genera).
I have examined the original description of all. About
1400 publications have been checked and about 1010 relevant
ones are listed.
By loaches I understand here the suborder Cobitoidei. Some
authors have considered the family Catostomidae as the sister-group
of all other Cobitoidei (e.g. Šlechtová et al., 2007).
THE RAFFLES BULLETIN OF ZOOLOGY 2012
INTRODUCTION
3
Μα χελιδν αρ ο ποιε
[One nucleotide does not a species make *]
Aristotle (384–322 BC)
[*apocryphal; usually translated as
"one swallow doest not a summer make"]
Other authors have found that Catostomidae are the sistergroup
of all other Cypriniformes (e.g. Mayden et al., 2009;
Chen et al., 2009 [labelled as part of Cobitoidea in their tree,
but clearly sister-group to all other Cypriniformes]); part of
these same authors had also found Catostomidae as sistergroup
of all other Cobitoidei (Tang et al., 2010) or as sistergroup
of Gyrinocheilidae, together being the sister-group to
Cyprinidae (He et al., 2008). In a morphological study, Conway
(2011) found that Catostomidae are the sister-group of
Gyrinocheilidae, these together are sister-group of the remaining
Cobitoidei, which is sister-group of Cyprinidae +
Psilorhynchidae.
In view of these conflicting conclusions (and awaiting the
next ones ....), I follow Šlechtová et al. (2007) and exclude
Catostomidae from Cobitoidei. Among the above analyses,
theirs is based on the largest number of genera and species
of Cobitoidei.
Content. — First, the following checklist is far from an ultimate
inventory of the loaches of the world: it merely presents
what is known today. Many discoveries are still ahead
of us and a great amount of work remains to be done before
we reach an acceptable level of knowledge. I am aware of
the existence of about 100 unnamed species which, hopefully,
should be described in the next few years, from throughout
the range of the superfamily.
This list deals with taxonomy and nomenclature. The two
topics are intimately related but should not be confused.
Taxonomy is about species (the animals) and studies their
distinctness, their morphology, their phylogeny and ultimately
organises them in a system, under scientific or philosophical
concepts that may vary among individual scientists. Nomenclature
is only about the names of animals; it is governed by
a set of rules (the International Code of Zoological Nomenclature;
ICZN, 1999; hereunder Code) intended to be applied
universally. Nomenclature is not concerned by scientific
conclusions and hypotheses, or philosophical concepts,
and leaves total taxonomic freedom to individual scientists;
it is concerned only with the names applied to an animal.
In using the checklist, attention should be paid so as to not
confuse taxonomic and nomenclatural discussions. Taxonomy
is a matter of hypotheses and open to discussion, while