Venomous snake
Belcher's sea snake ("Hydrophis belcheri"), which many times is mistakenly called the hook-nosed sea snake ("Enhydrina schistosa"), has been erroneously popularized as the most venomous snake in the world, due to the first edition of Ernst and book, "Snakes in Question: The Smithsonian Answer Book", published in 1996.
Prominent venom expert Associate Professor Bryan Grieg Fry has clarified the error: "The hook nosed myth was due to a fundamental error in a book called "Snakes in Question". In there, all the toxicity testing results were lumped in together, regardless of the mode of testing (e.g., subcutaneous vs. intramuscular vs. intravenous vs. intraperitoneal). As the mode can influence the relative number, venoms can only be compared within a mode. Otherwise, it's apples and rocks." Belcher's sea snake's actual LD (recorded only intramuscularly) is 0.24 mg/kg and 0.155 mg/kg. Studies on mice and human cardiac cell culture show that venom of the inland taipan, drop by drop, is the most toxic among all snakes.
Russell's viper
Russell's viper ("Daboia russelii") is a species of venomous snake in the family Viperidae. of venomous Old World vipers. The single member species, "D. russelii", is found in Asia throughout the Indian subcontinent, much of Southeast Asia, southern China and Taiwan. The species is named for Patrick Russell (1726–1805), a Scottish herpetologist who first described many of India's snakes, and the name of the genus is from the Urdu word meaning "that lies hid", or "the lurker". In Bengali this snake is called chandroborha (চন্দ্রবোড়া) since it carries lenticular or more precisely lunar marks all over its body. Apart from being a member of the big four snakes in India, "Daboia" is also one of the genera responsible for causing the most snakebite incidents and deaths among all venomous snakes on account of many factors, such as their wide distribution, generally aggressive demeanor, and frequent occurrence in highly populated areas.