Monday, 3 March 2014

Promachoteuthis sulcus: The squid with the human like teeth

Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Teuthida
Family: Promachoteuthidae
Genus: Promachoteuthis
Species: Promachoteuthis sulcus
Conservation Status: Not Assessed
Common Names: Called the squid with the human-like teeth or something similar, it doesn't yet have an official common name

This weird, alien looking creature is scientifically known as Promachoteuthis sulcus. It is a rare, newly discovered deep-sea squid, best known for its seemingly human-like mouth. The species is only known by a single specimen that was caught in 2007, in the nets of the German research vessel "Walther Herwig", near the Tristan Da Cunha islands, at a depth of 1,750 to 2,000 m (5,740–6,560 ft).

Don't be frightened by its appearance as it's a mere inch long! As for the human like-teeth.. Well, sometimes appearances are deceptive. As explained down below, the human-like dentures are something totally different!

image showing the Walther Herwig research vessel
The Walther Herwig research vessel 

As aforementioned, the little knowledge we have for the species comes from a single, immature female, 25 mm  (~1 inch) long specimen.

P.sulcus ventrolateral view
Image of the P.sulcus specimen caught in 2007
Ventrolateral view 

It has eight arms, two large tentacles, and what is seemingly a mouth with human-like dentures. The species is distinguished from related taxa on the basis of numerous morphological features, including:
  • Nuchal fusion between the head and mantle 
  • Arm suckers are way larger compared to club suckers 
  • Greater width of tentacle base than arm base 
  • A recessed club base 
  • The presence of an aboral tentacle groove

P.sulcus dorsal and ventral view sketch
P.sulcus drawing -  dorsal and ventral view

For more extensive information and close up images of the various body accessories (head, arms, tentacles etc) please use the first link in the references section.

About the human like "mouth"
Squids often have tough, razor-sharp beaks that they use to chop and chew their prey. P. Sulcus is no exception and does have a small beak, lurking deep inside the mouth, although it is not visible on the photos.

As for the creepy teeth, they are actually circular, folded lips, with only the upper and lower portions visible.

A close up of the p. sulcus mouth
Mouth close-up 

Is it dangerous? 
Despite its hideous appearance, Promachoteuthis sulcus poses no threat two humans, for two reasons.

First, it is a deep sea squid. Seeing one in its natural habitat is highly unlikely. Secondly, the squid is very, very small. The 2007 specimen was barely an inch long, and scientists say they don't grow to be much bigger.

Interesting Facts about Promachoteuthis sulcus 
The creature has gained a small following as an internet meme, for obvious reasons. There was a time that social media were full of MEME images, like this one:

You may also like
  • Bigfin squids: Think Promachoteuthis sulcus is scary? Think again! Bigfin squids look a lot like the aliens from the Independence day film! Not to mention that they can get to be at least 7 meters long!

References & Further Reading
- Young, Richard E. and Michael Vecchione. 2007. Promachoteuthis sulcus Young, Vecchione and Roper, 2007. Version 15 November 2007. in The Tree of Life Web Project
- Young, R., Vecchione, M., & Roper, C. (2007). A new genus and three new species of decapodiform cephalopods (Mollusca: Cephalopoda) Reviews in Fish Biology and Fisheries, 17 (2-3), 353-365 DOI: 10.1007/s11160-007-9044-z

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