The probability of other creatures organically dying blue

[rhecht]

What is the probability of other sea creatures organically dyeing blue besides the trunculus snail?

[yepstein]

Don't forget about Brandaris & others

[David H.]

This history of textile dyeing is well-documented (everyone wore clothing and everyone was looking for colorfast dye sources to color them with).

Natural dyes were very few and animal-derived dyes even fewer.
Nothing sea-dwelling other than Murex family and cuttlefish.
So, those who posit that Murex was not the chilazon would also be positing (without evidence) the existence of a sea-dwelling dye source unknown to science, archaeology, and literature.

https://en.wikipedia.org/wiki/Natural_d ... al-derived dyes[edit]

• Cochineal insect (red)
• Cow urine (Indian yellow)
• Lac insect (red, violet)
• Murex snail (purple, indigo blue)
• Octopus/Cuttlefish (sepia brown)

Plant-derived dyes[edit]

• Catechu or Cutch tree (brown)
• Gamboge tree resin (dark mustard yellow)
• Chestnut hulls (peach to brown)
• Himalayan rhubarb root (bronze, yellow)
• Indigofera leaves (blue)
• Kamala seed pods (yellow)
• Madder root (red, pink, orange)
• Mangosteen peel (green, brown, dark brown, purple, crimson)[6]
• Myrobalan fruit (yellow, green, black, source of tannin)
• Pomegranate rind (yellow)
• Teak leaf (crimson to maroon)[7]
• Weld herb (yellow)
• Juglans Nigra or Black Walnut hulls (brown, black, source of tannin)
• Rhus typhina or Staghorn Sumac tree (brown, source of tannin)

[Mr. Genugshoin]

The Medrash says that it was nignaz- this is also brought down by the Gra lehalacha.
It is not improbable that a creature went extinct and is unknown to science.