Three species of sailfin catfishes (Pterygoplichthys) native to South America, P. multiradiatus,
P. pardalis and P. disjunctivus, have been collected recently in several countries in southeastern Asia.
Pterygoplichthys multiradiatus is known to reproduce in Taiwan, and P. pardalis is presumed to be reproducing
in Singapore given the frequency of its collection and the range in size of specimens collected. The status
of the species elsewhere in southeastern Asia is less certain. These catfishes are common in the pet trade and
almost certainly were released by aquarists. It is likely that these fishes will become widely established in
southeastern Asia and will have negative environmental impacts, including alteration of food webs, in nonnative
areas.
sailfin catfishes found in
Indonesia as Pterygoplichthys pardalis. Specimens in the
Zoological Reference Collection, Raffles Museum of
Biodiversity Research (ZRC), and the Florida Museum of
Natural History (UF) document the presence of
Pterygoplichthys pardalis in Singapore, Peninsular Malaysia,
Java and Sumatra, and Pterygoplichthys disjunctivus in
Singapore, Java and Taiwan (see Material Examined).
With about 80 genera and 680 species (Reis et al., 2003),
Loricariidae is the largest family of catfishes (Siluriformes).
Loricariids are endemic to South America and Panama and
are characterized by having large bony plates and a ventral
mouth. Loricariids with 10 or more dorsal fin rays are
members of the genus Pterygoplichthys and are referred to
as sailfin catfishes. All specimens of Pterygoplichthys from
southeastern Asia lack an elevated supraoccipital process and
have the supraoccipital bone bordered posteriorly by three
scutes.
A group of four closely related species of
Pterygoplichthys share these traits (Weber, 1991, 1992): P.
multiradiatus, P. anisitsi, P. disjunctivus, and P. pardalis.
Among these species, only P. anisitsi has light spots on a
dark background, and only P. multiradiatus has a pattern of
uncoalesced dark spots on a light background.
Pterygoplichthys disjunctivus and P. pardalis possess a dorsal
pattern of coalesced dark spots on a light background.
Pterygoplichthys disjunctivus differs from P. pardalis in
having dark spots on the venter coalesced to form a
vermiculate pattern (Fig. 1); in P. pardalis the venter is
covered with discrete spots (Fig. 2). Specimens at ZRC and
UF are easily identified as P. pardalis and P. disjunctivus.
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