Batasio
Encyclopedia
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
.
in 1860 with Batasio buchanani (a needless renaming of Batasio batasio) designated as type
.
B. pakistanicus, described in 1989, is tentativelly placed in Batasio, but its generic placement is questionable.
and mainland Southeast Asia
. B. affinis is found in Myanmar
. B. havmolleri is found in Ronpibun, Thailand
. B. tigrinus is also recorded from Thailand. B. dayi originates from the Salween
and Irrawaddy River drainages in Myanmar. B. elongatus is found in southwestern Myanmar
. B. macronotus originates from eastern Nepal
. B. pakistanicus is found in the Indus River
.
B. niger is found in India
. B. batasio also originates from northern India
where it shares its habitat with Mystus vittatus. B. fasciolatus is known from the Tista River drainage, a tributary of the Brahmaputra River
. B. merianiensis is found in the Brahmaputra River drainage. B. sharavatiensis originates from the Sharavati River in Uttara Kannada
, Karnataka
. B. spilurus is known from the Brahmaputra River drainage in the vicinity of Dibrugarh
. B. tengana is known from the Ganges
and the Brahmaputra River drainages; it is apparently restricted to upper reaches of larger rivers. B. travancoria is distributed in the Chittar
, Kallada
and Pamba River
s in southern Kerala
and is considered a rare species.
and 45 mm (1.8 in) SL respectively. The other species range from 55–101 mm (2.2–4.0 in) SL.
B. affinis, B. dayi, and B. havmolleri have bars or bands, spots or stripes, and are not plain-bodied. B. pakistanicus has a black humeral
spot with a dark streak on the dorsum
. B. batasio has a dark stripe along the lateral line
and another above. B. batasio does not exceed 10 centimetres (4 in). 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. B. tengana has bands descending from the dorsal surface to the lateral line. B. travancoria has a lateral stripe along the lateral line and a faint shoulder spot.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.
Batasio, like most other bagrids, are easy to sex. The male has a visible genital papilla
just fore of the anal fin. 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.
B. havmolleri hide among stones or submerged vegetation during the day and come out at night to feed.
B. batasio appears to mimic
Mystus vittatus, with which it inhabits the same habitat.
hobby. 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. 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.
B. batasio is another species in the hobby, but can be easily confused with Mystus vittatus. B. travancoria has only once been imported to the U.S. 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.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
(order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Bagridae
Bagridae
Bagridae are a family of catfish that originate from Africa and Asia from Japan to Borneo. These fish are commonly known as naked catfishes or bagrid catfishes.Large Bagrids are important as food fish. Some species are kept as aquarium fishes....
. These small fish are found in fast-flowing hillstreams throughout South
South Asia
South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...
and mainland Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
.
Taxonomy
Batasio was first described by Edward BlythEdward Blyth
Edward Blyth was an English zoologist and pharmacist. He was one of the founders of zoology in India....
in 1860 with Batasio buchanani (a needless renaming of Batasio batasio) designated as type
Biological type
In biology, a type is one particular specimen of an organism to which the scientific name of that organism is formally attached...
.
B. pakistanicus, described in 1989, is tentativelly placed in Batasio, but its generic placement is questionable.
Distribution
Batasio species are generally found throughout SouthSouth Asia
South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...
and mainland Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
. B. affinis is found in Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
. B. havmolleri is found in Ronpibun, Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
. B. tigrinus is also recorded from Thailand. B. dayi originates from the Salween
Salween River
The Salween is a river, about long, that flows from the Tibetan Plateau into the Andaman Sea in Southeast Asia. It drains a narrow and mountainous watershed of that extends into the countries China, Burma and Thailand. Steep canyon walls line the swift, powerful and undammed Salween, one of the...
and Irrawaddy River drainages in Myanmar. B. elongatus is found in southwestern Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
. B. macronotus originates from eastern Nepal
Nepal
Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...
. B. pakistanicus is found in the Indus River
Indus River
The Indus River is a major river which flows through Pakistan. It also has courses through China and India.Originating in the Tibetan plateau of western China in the vicinity of Lake Mansarovar in Tibet Autonomous Region, the river runs a course through the Ladakh district of Jammu and Kashmir and...
.
B. niger is found in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. B. batasio also originates from northern India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
where it shares its habitat with Mystus vittatus. B. fasciolatus is known from the Tista River drainage, a tributary of the Brahmaputra River
Brahmaputra River
The Brahmaputra , also called Tsangpo-Brahmaputra, is a trans-boundary river and one of the major rivers of Asia. It is the only Indian river that is attributed the masculine gender and thus referred to as a in Indo-Aryan languages and languages with Indo-Aryan influence...
. B. merianiensis is found in the Brahmaputra River drainage. B. sharavatiensis originates from the Sharavati River in Uttara Kannada
Uttara Kannada
Uttara Kannada also known as North Canara or North Kanara, is a district in the southern Indian state of Karnataka. It is bordered by the state of Goa and Belgaum District to the north, Dharwad District and Haveri District to the east, Shimoga District and Udupi District to the south and the...
, Karnataka
Karnataka
Karnataka , the land of the Kannadigas, is a state in South West India. It was created on 1 November 1956, with the passing of the States Reorganisation Act and this day is annually celebrated as Karnataka Rajyotsava...
. B. spilurus is known from the Brahmaputra River drainage in the vicinity of Dibrugarh
Dibrugarh
Dibrugarh is the headquarters of Dibrugarh district, Assam, India, and is the second largest city in Assam after Guwahati. It is situated on the banks of the Brahmaputra River, about north-east of Guwahati. It is the gateway to the three tea-producing districts of Tinsukia, Dibrugarh, and Sibsagar...
. B. tengana is known from the Ganges
Ganges River
The Ganges or Ganga, , is a trans-boundary river of India and Bangladesh. The river rises in the western Himalayas in the Indian state of Uttarakhand, and flows south and east through the Gangetic Plain of North India into Bangladesh, where it empties into the Bay of Bengal. By discharge it...
and the Brahmaputra River drainages; it is apparently restricted to upper reaches of larger rivers. B. travancoria is distributed in the Chittar
Chittar River
Chittar River and its five tributaries and numerous other contributing streams originate in the Courtallam hills of Tirunelveli District in the state of Tamil Nadu in southern India...
, Kallada
Kallada River
The Kallada River is one of two major rivers that flow through the Kollam District of Kerala, India. It originates on the Kulathupuzha hills near Ponmudi and travels for 121 km, flowing through Punalur, Pathanapuram, Kunnathur, Kottarakkara and Kollam before ending at Ashtamudi Lake...
and Pamba River
Pamba River
Pamba River is the third longest river in the South Indian state of Kerala after Periyar and Bharathappuzha and the longest river in the erstwhile princely state of Travancore...
s in southern Kerala
Kerala
or Keralam is an Indian state located on the Malabar coast of south-west India. It was created on 1 November 1956 by the States Reorganisation Act by combining various Malayalam speaking regions....
and is considered a rare species.
Appearance and anatomy
Batasio species typically have enlarged sensory pores on their head, laterally compressed heads and bodies, and at least 35 vertebrae. B. tengana, B. pakistanicus and B. spilurus differ from other Batasio species in that their adipose fin is much shorter. These fish are small catfish. B. pakistanicus and B. spilurus are the smallest species, reaching only 35 millimetres (1.4 in) SLFish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
and 45 mm (1.8 in) SL respectively. The other species range from 55–101 mm (2.2–4.0 in) SL.
B. affinis, B. dayi, and B. havmolleri have bars or bands, spots or stripes, and are not plain-bodied. B. pakistanicus has a black humeral
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
spot with a dark streak on the dorsum
Dorsum (anatomy)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
. B. batasio has a dark stripe along the lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
and another above. B. batasio does not exceed 10 centimetres (4 in). 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. B. tengana has bands descending from the dorsal surface to the lateral line. B. travancoria has a lateral stripe along the lateral line and a faint shoulder spot.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.
Batasio, like most other bagrids, are easy to sex. The male has a visible genital papilla
Genital papilla
The genital papilla is a part of female external genitalia not present in humans, which appears as a small, fleshy flab of tissue. The papilla covers the opening of the vagina....
just fore of the anal fin. 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.
Ecology
Batasio species generally are found in fast-flowing hillstreams. 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. B. tengana occurs in rivers and canals and is found in torrential streams. P. travancoria ccurs in hill streams and rivers at the bases of hills.B. havmolleri hide among stones or submerged vegetation during the day and come out at night to feed.
B. batasio appears to mimic
Mimic
In evolutionary biology, mimicry is the similarity of one species to another which protects one or both. This similarity can be in appearance, behaviour, sound, scent and even location, with the mimics found in similar places to their models....
Mystus vittatus, with which it inhabits the same habitat.
In the aquarium
B. tengana, though uncommon, is the most commonly encountered species of Batasio in the aquariumAquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
hobby. 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. 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.
B. batasio is another species in the hobby, but can be easily confused with Mystus vittatus. B. travancoria has only once been imported to the U.S. 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.
Species
- Batasio affinis BlythEdward BlythEdward Blyth was an English zoologist and pharmacist. He was one of the founders of zoology in India....
, 1860 - Batasio batasio (HamiltonFrancis Buchanan-HamiltonDr Francis Buchanan, later known as Francis Hamilton but often referred to as Francis Buchanan-Hamilton was a Scottish physician who made significant contributions as a geographer, zoologist, and botanist while living in India.The standard botanical author abbreviation Buch.-Ham. is applied to...
, 1822) - Batasio convexirostrum Darshan, Anganthoibi & Vishwanath, 2011
- Batasio dayi (Vinciguerra, 1890)
- Batasio elongatus Ng, 2004
- Batasio fasciolatus Ng, 2006
- Batasio feruminatus Ng & Kottelat, 2007
- Batasio havmolleri (Smith, 1931)
- Batasio macronotus Ng & Edds, 2004
- Batasio merianiensis (Chaudhuri, 1913)
- Batasio niger Vishwanath & Darshan, 2006
- Batasio pakistanicus Mirza & Jan, 1989
- Batasio procerus Ng, 2008
- Batasio sharavatiensis Bhatt & Jayaram, 2004
- Batasio spilurus Ng, 2006
- Batasio tengana (Hamilton, 1822)
- Batasio tigrinus Ng & Kottelat, 2001
- Batasio travancoria Hora & Law, 1941