In my previous blog while comparing two cladograms of Octopoda, Octopus bimaculoides and Hapalochlaena muculosa were shown as sister taxa in both relationships. A sister taxon relationship based on shared trait of ink sac and two sucker rows.There is an African proverb that embodies the importance of this blog,it states that “show me your friend and I’ll show you your character”.
Fig 1-Blue-ringed octopus, Hapalochlaena muculosa Marcello Di Francesco/courtesy of University of Miami
It is befitting to feature Hapalochlaena muculosa as organism of todays’ blog.Commonly known as the Blue-ringed octopus, it has numerous blue eyespots on its mantle as compared to the California two-spot octopus with only one blue eye spots below each eye.(Fig 1) (Lydia M. et al (2012)
Hapalochlaena sp. is also a small sized octopus but normally found along the southern coastal regions of Australia unlike O. bimaculoides found on the southern coast of California Santa Barbara stretching to San Quintin, Mexico. (Tranter, D.J.et al ,1973)
Hapalochlaena sp. is venomous and displays its numerous vibrant blue rings on mantle when disturbed. This creates an effective conspicuous warning display. The venom contains primarily tetradotoxin, is used to kill or paralyze its prey i.e. crabs and crayfish. (Sheumack et al,1978) Hapalochlaena muculosa was the first species with venom contain primarily tetrodotoxin unlike others that occurs as a poison in the skin, liver, muscle, eggs or ovaries. Tetradotoxin is a very potent neurotoxin that can paralyze and even kill humans.
Fun fact
Copulation in Hapalochlaena sp. is more vigorous than seen in other octopus and it lasts for about an hour. The male mounts and grasps the female securely and after a brief struggle the female subdues. Finally, the male deposits its sperm in the female’s oviduct using his hectocotylus.(Tranter, D.J.et al ,1973)
Joke of the day
I hope I’m not poisonous, says the first blue-ringed octopus
“Why?” asks the second blue-ringed octopus
“Because I just bit my lip.” said the first.
Reference
1.Lydia M. et al (2012) How does the blue-ringed octopus (Hapalochlaena lunulata) flash its blue rings? Journal of Experimental Biology 2012, 215: 3752-3757; doi: 10.1242/jeb.076869. Accessed on 4/10/2018 at http://jeb.biologists.org/content/215/21/3752.figures-only
2.Sheumack, D. D et al (1978). Maculotoxin: a neurotoxin from the venom glands of the octopus Hapalochlaena maculosa identified as tetrodotoxin. Science 199, 188-189. Accessed on 4/10/2018 at http://science.sciencemag.org/content/199/4325/188/tab-pdf
3.Tranter, D.J. & Augustine, O. (1973) Observations on the life history of the blue-ringed octopus Hapalochlaena maculosa. Marine Biology January 1973, Volume 18, issue 2 pp 115–128. Accessed on 4/10/2018 at https://doi.org/10.1007/BF00348686