Step 1: Understanding the Concept:
Vernacular or common English names of fishes often describe key morphological features (like lips, scales, or patterns) or their geographic distribution.
Associating these common names with their respective scientific names is standard practice in inland fisheries and aquaculture.
Step 2: Detailed Explanation:
Let us analyze the species of the genus Labeo listed in the options:
Labeo kontius is commonly known as the Cauvery carp.
Labeo dyocheilus is commonly known as the Brahmaputra carp or Kali-rohu.
Labeo dussumieri is commonly known as the Malabar carp or grass carp of Kerala.
Labeo fimbriatus is a medium carp endemic to the rivers of peninsular India.
The word "fimbriatus" refers to the fringed or fringed-lip structure of its mouth.
Consequently, its standard common English name is the "fringed-lipped peninsula carp".
It has a mouth that is inferior, transverse, and carries a distinct, fimbriated lower lip, which is an adaptation for feeding on detritus, algae, and benthic organisms.
Therefore, the scientific name of the fringed-lipped peninsula carp is Labeo fimbriatus.
The question contains a slight translation/printing error by using the word "vernacular name" instead of "scientific name" in the prompt, but the taxonomic choices point exclusively to identifying Labeo fimbriatus.
Step 3: Final Answer:
The scientific name of the fringed-lipped peninsula carp is Labeo fimbriatus.