Batasio

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Batasio
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Bagridae
Genus: Batasio
Blyth, 1860
Species

See text.

Batasio is a genus of catfish (order Siluriformes) of the family Bagridae. These small fish are found in fast-flowing hillstreams throughout South and mainland Southeast Asia.

Taxonomy[edit]

Batasio was first described by Edward Blyth in 1860 with Batasio buchanani (a needless renaming of Batasio batasio) designated as type.[1]

B. pakistanicus, described in 1989, is tentativelly placed in Batasio, but its generic placement is questionable.[2][3]

Distribution[edit]

Batasio species are generally found throughout South and mainland Southeast Asia.[2] B. affinis is found in Myanmar.[4] B. havmolleri is found in Ronpibun, Thailand.[5] B. tigrinus is also recorded from Thailand.[6] B. dayi originates from the Salween and Irrawaddy River drainages in Myanmar.[7] B. elongatus is found in southwestern Myanmar.[2] B. macronotus originates from eastern Nepal.[3] B. pakistanicus is found in the Indus River.[8]

B. niger is found in India.[9] B. batasio also originates from northern India where it shares its habitat with Mystus vittatus.[10] B. fasciolatus is known from the Tista River drainage, a tributary of the Brahmaputra River.[11] B. merianiensis is found in the Brahmaputra River drainage.[11] B. sharavatiensis originates from the Sharavati River in Uttara Kannada, Karnataka.[12] B. spilurus is known from the Brahmaputra River drainage in the vicinity of Dibrugarh.[11] B. tengana is known from the Ganges and the Brahmaputra River drainages; it is apparently restricted to upper reaches of larger rivers.[11] B. travancoria is distributed in the Chittar, Kallada and Pamba Rivers in southern Kerala and is considered a rare species.[12]

Appearance and anatomy[edit]

Batasio species typically have enlarged sensory pores on their head, laterally compressed heads and bodies, and at least 35 vertebrae.[11] B. tengana, B. pakistanicus and B. spilurus differ from other Batasio species in that their adipose fin is much shorter.[11] These fish are small catfish.[2] B. pakistanicus and B. spilurus are the smallest species, reaching only 35 millimetres (1.4 in) SL and 45 mm (1.8 in) SL respectively.[11] The other species range from 55–101 mm (2.2–4.0 in) SL.[11]

B. affinis, B. dayi, and B. havmolleri have bars or bands, spots or stripes, and are not plain-bodied.[12] B. pakistanicus has a black humeral spot with a dark streak on the dorsum.[12] B. batasio has a dark stripe along the lateral line and another above.[12] B. batasio does not exceed 10 centimetres (4 in).[10] B. fasciolatus and B. tigrinus are the only Batasio species in which the adult colouration consists of five or six vertical dark brown bars on a light brown body.[11] B. tengana has bands descending from the dorsal surface to the lateral line.[12] B. travancoria has a lateral stripe along the lateral line and a faint shoulder spot.[12]B. sharavatiensis is the only Batasio that has a completely plain and colourless body; it's adipose fin is almost confluent (continuous) with the caudal fin save for a small notch.[12]

Batasio, like most other bagrids, are easy to sex. The male has a visible genital papilla just fore of the anal fin.[10] Gravid female B. tengana (SE Asian form) are easy to identify because the pink eggs can be seen through their semi-transparent belly when they swim near light.[10]

Ecology[edit]

Batasio species generally are found in fast-flowing hillstreams.[2] B. havmolleri is found in rivers and streams with moderate to swift current and a predominantly rocky bottom, and is less often in slow-flowing streams with a muddy substrate.[5] B. tengana occurs in rivers and canals and is found in torrential streams.[13] P. travancoria ccurs in hill streams and rivers at the bases of hills.[14]

B. havmolleri hide among stones or submerged vegetation during the day and come out at night to feed.[5]

B. batasio appears to mimic Mystus vittatus, with which it inhabits the same habitat.[10]

In the aquarium[edit]

B. tengana, though uncommon, is the most commonly encountered species of Batasio in the aquarium hobby.[10] B. tengana does well in captivity, and has been bred in captivity. The fish spawned in soft neutral water, but raising the fry, of which there were over 200, proved difficult.[10] The temperature for the Indian species should remain between 20–22°C (68–72°F; the Southeast Asian Batasio will tolerate slightly warmer waters. It appears that all Batasio need a lot of current and a high oxygen content.[10]

B. batasio is another species in the hobby, but can be easily confused with Mystus vittatus.[10] B. travancoria has only once been imported to the U.S.[10] In captivity, the experience of one aquarist is that specimens of B. travancoria show little interest in all foods offered and slowly lose weight over a span of a few months and perish.[10]

Species[edit]

There are currently 17 recognized species in this genus:[1]

References[edit]

  1. ^ a b Froese, Rainer, and Daniel Pauly, eds. (2011). Species of Batasio in FishBase. December 2011 version.
  2. ^ a b c d e f Ng, Heok Hee (March 2004). "Batasio elongatus, a new species of bagrid catfish from southwest Myanmar (Siluriformes: Bagridae)" (PDF). Ichthyol. Explor. Freshwaters 15 (1): 67–70. 
  3. ^ a b c Ng, Heok Hee; Edds, David R. (December 2004). "Batasio macronotus, a new species of bagrid catfish from Nepal (Teleostei: Bagridae)" (PDF). Ichthyol. Explor. Freshwaters 15 (4): 295–300. 
  4. ^ Froese, Rainer and Pauly, Daniel, eds. (2007). "Batasio affinis" in FishBase. June 2007 version.
  5. ^ a b c Froese, Rainer and Pauly, Daniel, eds. (2007). "Batasio havmolleri" in FishBase. June 2007 version.
  6. ^ Froese, Rainer and Pauly, Daniel, eds. (2007). "Batasio tigrinus" in FishBase. June 2007 version.
  7. ^ Froese, Rainer and Pauly, Daniel, eds. (2007). "Batasio dayi" in FishBase. June 2007 version.
  8. ^ Froese, Rainer and Pauly, Daniel, eds. (2007). "Batasio pakistanicus" in FishBase. June 2007 version.
  9. ^ Froese, Rainer and Pauly, Daniel, eds. (2007). "Batasio niger" in FishBase. June 2007 version.
  10. ^ a b c d e f g h i j k Linder, R. Shane (March 2000). "The Catfishes of Asia Family Bagridae part one" (PDF). Cat Chat 1 (1). 
  11. ^ a b c d e f g h i j k Ng, Heok Hee (2006). "The identity of Batasio tengana (Hamilton, 1822), with the description of two new species of Batasio from north-eastern India (Teleostei: Bagridae)" (PDF). Journal of Fish Biology 68 (Supplement A): 101–118. doi:10.1111/j.0022-1112.2006.001019.x. 
  12. ^ a b c d e f g h i Bhatt, Anuradha; Jayaram, K.C. (February 2004). "A New Species of the Genus Batasio Blyth (Siluriformes: Bagridae) from Sharavati River, Uttara Kannada, Karnataka" (PDF). Zoos' Print Journal 19 (2): 1339–1342. Archived from the original on 2009-10-26. 
  13. ^ Froese, Rainer and Pauly, Daniel, eds. (2007). "Batasio tengana" in FishBase. June 2007 version.
  14. ^ Froese, Rainer and Pauly, Daniel, eds. (2007). "Batasio travancoria" in FishBase. June 2007 version.
  15. ^ "Batasio convexirostrum, a new species of catfish (Teleostei: Bagridae) from Koladyne basin, India" (PDF). Zootaxa 2901: 52–58. 2011. 
  16. ^ Ng & Kottelat. "Batasio feruminatus, a new species of bagrid catfish from Myanmar (Siluriformes: Bagridae), with notes on the identity of B. affinis and B. fluviatilis.". Ichthyol. Explor. Freshwaters (PDF) 18: 289–300. 
  17. ^ Ng, Heok Hee (March 2008). "Batasio procerus, a new species of catfish from northern Myanmar (Siluriformes: Bagridae)". Ichthyological Exploration of Freshwaters 19 (1): 1–6.