New Loach Species in Meghalaya

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Context

• A new species of loach, named Schistura sonarengaensis, has been identified in Meghalaya’s South Garo Hills district, close to the Bangladesh border.
• This freshwater bottom-dwelling fish was discovered in Sonarenga, Nakama, and Chiabol caves within the district.

 Species Description

• Schistura sonarengaensis is described as a new species of nemacheilid loach from three cave-dwelling populations in the South Garo Hills district.
• This species is noted for its prominent eyes and distinctive pattern: 13-26 vertically elongated to circular black blotches on a grayish-black mid-lateral stripe over a dull white or pale-beige body.

 Unique Characteristics

• Unlike typical subterranean species, Schistura sonarengaensis does not have the complete loss of eyes or pigmentation.
• However, it does exhibit reduced pigmentation compared to surface-dwelling relatives. Genetic molecular analysis has confirmed its distinction from other known species in the region.

 Distinction from Related Species

• Although somewhat pale, the new species retains prominent eyes and is not blind like other cave species found in Jaintia and Khasi Hills.
• It is distinct from other Schistura species in the Barak-Surma-Meghna and adjacent river drainages of northeast India, except for Schistura syngkai.

 Loaches

• Loaches are fish belonging to the superfamily Cobitoidea.
• These freshwater, bottom-dwelling fish are found in rivers and creeks throughout Eurasia and northern Africa.
• The group is highly diverse, with 1,249 known species distributed across approximately 107 genera and 9 families.

Description

Morphological Diversity

• Loaches exhibit a wide range of morphologies, making them challenging to characterize as a whole.
• They vary in size from the 23 mm (1 in) miniature eel-loach, Pangio longimanus, to the 50 cm (20 in) imperial flower loach, Leptobotia elongata, which can weigh up to 3 kg (6.6 lbs).
• Most loaches are small, narrow-bodied, and elongate, featuring minute cycloid scales often embedded under the skin, and three or more pairs of whisker-like barbels at the mouth.

 Body Shape and Pigmentation

• While the type species of the family Cobitidae, Cobitis taenia, exhibits a typical body shape and pigment pattern for Cobitoidea, many loaches have eel-like or stout-bodied forms.
• Some balitorids also have large, visible scales. Notably, loaches from the families Cobitidae, Botiidae, and Serpenticobitidae possess a bifid, protrusible spine below the eye or between the eye and the snout tip.

 Habitat and Distribution

• Loaches inhabit a variety of environments across Europe, northern Africa, and central and Southeast Asia.
• While many species are found in rocky mountain streams at high elevations, others live in lowland areas.
• Several families include blind, cave-dwelling species adapted to subterranean life.

 Relationship with Humans

Economic Importance

• Loaches are significant in the food industry, particularly in East and Southeast Asia, where they are commonly found in markets.

 Aquarium Trade

• Loaches are popular in the aquarium trade. Notable examples include the clown loach (Chromobotia macracanthus), kuhli loach (Pangio kuhlii), and dwarf chain loach (Ambastaia sidthimunki). Botiid and gastromyzontid loaches are also occasionally traded.

 Invasive Species

• Although loaches are native to the Old World, the oriental weatherfish (Misgurnus anguillicaudatus), also known as the dojo loach, has been introduced to parts of the United States.
  

 SOURCE: THE PRINT