Morphological convergence in tendaguriid dorsal vertebrae and cephalopods

I’ve been away for two weeks with Fiona in Kefalonia, one of the Greek islands. While we were there, we ate this excellent meal:

Excellent Greek meal. Back row: grilled octopus; middle row (left to right): sardines, shrimp saganaki; front row: deep-fried calamari ” data-medium-file=”https://svpow.files.wordpress.com/2023/10/pxl_20231007_165101354.jpg?w=300″ data-large-file=”https://svpow.files.wordpress.com/2023/10/pxl_20231007_165101354.jpg?w=480″ class=”size-full wp-image-21335″ src=”https://svpow.files.wordpress.com/2023/10/pxl_20231007_165101354.jpg?w=480&h=360″ alt=”Excellent Greek meal. Back row: grilled octopus; middle row (left to right): sardines, shrimp saganaki; front row: deep-fried calamari” width=”480″ height=”360″ srcset=”https://svpow.files.wordpress.com/2023/10/pxl_20231007_165101354.jpg?w=480&h=360 480w, https://svpow.files.wordpress.com/2023/10/pxl_20231007_165101354.jpg?w=960&h=720 960w, https://svpow.files.wordpress.com/2023/10/pxl_20231007_165101354.jpg?w=150&h=113 150w, https://svpow.files.wordpress.com/2023/10/pxl_20231007_165101354.jpg?w=300&h=225 300w, https://svpow.files.wordpress.com/2023/10/pxl_20231007_165101354.jpg?w=768&h=576 768w” sizes=”(max-width: 480px) 100vw, 480px” />

Excellent Greek meal. Back row: grilled octopus; middle row (left to right): sardines, shrimp saganaki; front row: deep-fried calamari

As we made our way through the calamari, we noticed this chunk:

Take a closer look and I think you will be struck, as I was, by the resemblance to an anterior dorsal vertebra of a tendaguriid sauropod in posterior view:

Here for comparison is the more anterior of the two known dorsal vertebrae of the enigmatic sauropod Tendaguria:

Bonaparte, Heinrich and Wilde (1999:figure 11B): anterior dorsal vertebra of Tendaguria in posterior view ” data-medium-file=”https://svpow.files.wordpress.com/2023/10/bonaparteetal1999-figure-11b-tendaguria-dorsal.jpeg?w=300″ data-large-file=”https://svpow.files.wordpress.com/2023/10/bonaparteetal1999-figure-11b-tendaguria-dorsal.jpeg?w=480″ class=”size-full wp-image-21343″ src=”https://svpow.files.wordpress.com/2023/10/bonaparteetal1999-figure-11b-tendaguria-dorsal.jpeg?w=480&h=366″ alt=”Bonaparte, Heinrich and Wilde (1999:figure 11B): anterior dorsal vertebra of Tendaguria in posterior view” width=”480″ height=”366″ srcset=”https://svpow.files.wordpress.com/2023/10/bonaparteetal1999-figure-11b-tendaguria-dorsal.jpeg?w=480&h=366 480w, https://svpow.files.wordpress.com/2023/10/bonaparteetal1999-figure-11b-tendaguria-dorsal.jpeg?w=150&h=114 150w, https://svpow.files.wordpress.com/2023/10/bonaparteetal1999-figure-11b-tendaguria-dorsal.jpeg?w=300&h=228 300w, https://svpow.files.wordpress.com/2023/10/bonaparteetal1999-figure-11b-tendaguria-dorsal.jpeg 696w” sizes=”(max-width: 480px) 100vw, 480px” />

Bonaparte, Heinrich and Wilde (1999:figure 11B): anterior dorsal vertebra of Tendaguria in posterior view.

If you doubt me, take a look at this red-cyan anaglyph and appreciate the perfect 3D structure, with the diapophyseal wings stretching out laterally from a point some way anterior to the cotyle. (Evidently the neural arch has been destroyed by post-mortem damage):

What are we seeing here? An unprecendented example of horizontal gene transfer? Or simply convergance based on similarity of lifestyle?

References

• Bonaparte, Jose F., Wolf-Dieter Heinrich and R. Wild. 2000. Review of Janenschia WILD, with the description of a new sauropod from the Tendaguru beds of Tanzania and a discussion on the systematic value of procoelous caudal vertebrae in the sauropoda. Palaeontographica Abt. A 256(1-3):25-76.