Zby

Zby is known solely from its holotype, a closely associated partial skeleton including a complete tooth with root, a fragment of cervical neural arch, an anterior chevron, and an almost complete right pectoral girdle and forelimb. It was discovered in 1996 in the Lourinhã Formation, Portugal by Octávio Mateus.

Zby was first described and named by Octávio Mateus, Philip D. Mannion and Paul Upchurch in 2014 and the type species is Zby atlanticus, although it was initially thought to be Turiasaurus riodevensis.

Zby is differentiated from other sauropods based on four autapomorphies, including a prominent posteriorly projecting ridge on the humerus at the level of the deltopectoral crest. Zby is suggested to be closely related to T. riodevensis from Spain and Portugal, based on its tooth morphology, extreme anteroposterior compression of the proximal end of the radius, and strong beveling of the lateral half of the distal end of the radius, while some other forelimb traits distinguish these two genera. Nearly all other anatomical features suggest that Zby is a non-neosauropod eusauropod, confirming its position as a turiasaurian. Zby is estimated to measure around 15 to 18 metres (49 to 59 ft) in length.