Description:
They are diagnosed (together with Chandramara)
from other members of the Bagridae in possessing large
sensory pores on the head, a narrow mental region,
the transversely elongated, bar-like entopterygoid,
and the close contact of the metapterygoid with the
quadrate (Mo, 1991). Batasio is distinguished
from Chandramara by the absence (vs. presence)
of a pair of prominent posterior processes on the
anterior part of the vomer. Dorsal spines (total):
1 - 1; Dorsal soft rays (total): 7-7; Anal spines:
4 -5; Anal soft rays: 8 -9. dorsal spine length
10.7-12.4% SL; length of adipose-fin base 30- 33.3%
SL; body depth at anus 18.7-21.1% SL; snout length
38.3-41.5% HL; eye diameter 18.2-23.5% HL; interorbital
distance 25.9-28.6% HL. Habitat:
Batasio species are small, laterally compressed
bagrid catfishes generally found in fast-flowing hill
streams throughout South Asia, Myanmar, the Salween
and Mae Khlong drainages of Thailand and the northern
Malay Peninsula. Occurs in rivers and streams with
moderate to swift current and a predominantly rocky
bottom; less often in slow-flowing streams
with a muddy substrate. Hides among stones or submerged
vegetation during the day and comes out at night to
feed. Colouration: Body with dark
brown predorsal oblique bar and a dark brown spot
on the side below the adipose fin. Etymology:
The genus name Batasio:
from the local (Bengali) name of the fish (batasio
or batashi). The
specific name fluviatilis:
of a river, presumably referring to the type locality,
described as a “stream”.
Asia:
Malay Peninsula, south of isthmus of Kra and north
of Perak River basin and Terengganu River. Type
locality: Klong Thalerng near Ronpibun, Peninsular
Siam.
Batasio
fluviatilis Adult with young-note the juvenile
body pattern
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