Description:
There are three species in this genera: X. dorsalis,
X.
xiurenensis and X.
gigas. Dorsal soft rays (total): 8; Anal soft
rays: 12. Xiurenbagrus dorsalis can be diagnosed
from its congeners by the following combination of
characters: 7 dorsal-fin branched rays (vs. 6 in X.
xiurenensis and X. gigas); pelvic-fin
origin opposite base of fourth branched dorsal-fin
ray (pelvic-fin insertion posterior to dorsal-fin
base in X. xiurenensis and X. gigas);
serrations absent on the posterior edge of pectoral-fin
spine (vs. strong serrations present in X. xiurenensis
and X. gigas); adipose fin confluent with
caudal fin (vs. adipose fin posteriorly with a free
flap and not confluent with caudal fin in X. xiurenensis
and X. gigas); maxillary barbel longer than
head length and reaching posterior tip of pectoral-fin
(vs. maxillary barbel shorter than head length, reaching
or slightly exceed pectoral-fin insertion in X.
xiurenensis and X. gigas); eyes absent
(vs. small eyes present in X. xiurenensis
and X. gigas). Habitat:
Inhabits a very small underground stream with substrate
of small rocks. The stream flows across the bottom
of the well. A pump is connected to a 4 m depth well
with plastic piping. The type specimen emerged through
the water during pumping. Etymology:
The specific name dorsalis: dorsal, referring
to unique position of dorsal-fin origin (posterior
to vertical line at tip of pectoral fins) when compared
with its congeners. Remarks:
The description of X. dorsalis brings the
currently recognized diversity of this genus to three
species, all of which are distributed in the Pearl
River basin. There are many unique characters of Xiurenbagrus
dorsalis when compared with X. xiurenensis
and X. gigas as listed above. Though
Xiurenbagrus dorsalis is a blind catfish,
it is placed in Xiurenbagrus because of the
presence of two patches of vomerine teeth. This character
is not found in any other species of Amblycipitidae
except those of the genus Xiurenbagrus.
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