• xarcharhinus obscurus,
• varcharhinus obscurus,
• farcharhinus obscurus,
• darcharhinus obscurus,
• czrcharhinus obscurus,
• csrcharhinus obscurus,
• cwrcharhinus obscurus,
• cqrcharhinus obscurus,
• caecharhinus obscurus,
• cadcharhinus obscurus,
• cafcharhinus obscurus,
• catcharhinus obscurus,
• ca5charhinus obscurus,
• ca4charhinus obscurus,
• carxharhinus obscurus,
• carvharhinus obscurus,
• carfharhinus obscurus,
• cardharhinus obscurus,
• carcgarhinus obscurus,
• carcbarhinus obscurus

The adjective form of the term "carcharhinus obscurus" is "carcharhinus obscurus". No change is needed for the adjective form as it retains the same spelling as the noun form.

The plural form of "Carcharhinus obscurus" is "Carcharhinus obscurus." The word remains the same in its plural form as it is a scientific name.

The singular form of the word "Carcharhinus Obscurus" is "Carcharhinus Obscurus". It is already singular and refers to a specific species of shark commonly known as the dusky shark.