Postcranial skeleton In 2011, Caine and Benton stated that Hauffiopteryx has fewer than 46 vertebrae in front of its hips (presacral vertebrae) and typically over 34 but under 39 between its hips and the bend in its tail. Maxwell and Cortés in 2020 described the lectotype as having 45 or 46 presacral vertebrae and a total of 81 vertebrae before the bend in the tail (preflexural vertebrae), with this bend composed of three vertebrae followed by more than 55 postflexural vertebrae. The upper ends of the dorsal ribs (those in the trunk region) are strongly forked, making them double-headed. Gastralia (belly ribs) are present along the underside of the trunk. This series of elements reaches far back, all the way to the level of the 35th vertebra. The scapulae (shoulder blades) of Hauffiopteryx have wide lower ends due to their front margins extending forwards. The front edge of each coracoid (shoulder bones located below the scapulae) is concave. No space is enclosed between the humeri (upper arm bones) and the radii and ulnae (lower arm bones), being tightly packed together. This is also the case for the other bones in the upper parts of the limbs, forming a mosaic-like pattern. Each forelimb contains four main digits, and the front edge of the limb consists of some elements with indentations on their front edges. The lower pelvic bones (the pubic bones and ischia) are narrow and pillar-shaped. Unusually, the ends of these bones which form the hip socket are fused together, but the bones markedly diverge away from the socket. The thin femora (thighbones) each bear a strong site for the articulation of the fibula (rear shin bone). The fibulae are also much larger than the tibiae (front shin bones). While the front edges of the hindlimbs contain some notched elements like the forelimbs, there are only three main digits in each rear limb. These digits closely approach each other towards the tip of the limb. Classification Both the original description by Maisch and the redescription of the English specimens found that Hauffiopteryx might be either a basalmost member of Eurhinosauria or a basalmost member of Thunnosauria (which is an equivalent position to a basalmost member of Stenopterygiidae sensu Maisch [2008] with exclusion of Ichthyosaurus). References Early Jurassic ichthyosaurs Fossil taxa described in 2008 Ichthyosaurs of Europe Ichthyosauromorph genera