Hauffiopteryx was first described by Michael W. Maisch on the basis of some specimens that previously referred to
Stenopterygius hauffianus. Maisch found that the lectotype of S. hauffianus can be determined as Stenopterygius cf. S. quadriscissus at best, and therefore this species should be considered a nomen dubium. He also found out that most specimens previously referred to S. hauffianus can be referred to S. quadriscissus, while the rest belongs to a highly distinctive new taxon that can't be referred to any valid species of Stenopterygius.[2]
Hauffiopteryx is known from the
SMNS 51552, SMNS 80225 and probably the poorly preserved SMNS 81965. They were collected from the Harpoceras semicelatum-elegantulum-exaratum ammonoid subzones (Lias ε II1-5, about 182.7-181.8 mya), Harpoceras tenuicostatum-falcifer zones, of the Posidonia Shale.[2]
Additional materials were described by Hannah Caine and
Michael J. Benton in 2011, from the early Toarcian of Strawberry Bank, Ilminster of England. The specimens are all juveniles or infants which preserved almost complete skeletons and some skulls. They include BRLSI M1399 (which was described earlier by Maisch), BRLSI M1400, BRLSI M1401, BRLSI M1403, BRLSI M1404 and BRLSI M1406.[3]
Etymology
Hauffiopteryx was originally recognized by
generic name honors the Hauff family from Holzmaden, for their generation-long work to increase the knowledge on the Posidonia Shale and its fauna, especially the ichthyosaurs, and pteryx (πτερυξ), Greek for "fin" or "wing". The specific name means typical.[2]H. altera comes from the Latin word meaning "different from" or "other" due to the differences between it and H. typicus.[1]
Description
Size comparison
Hauffiopteryx is a relatively small ichthyosaur, reaching 2–3 m (6.6–9.8 ft) in length.[1][3]
Skull
The snout of Hauffiopteryx is short, but also very thin, tapering to a point.
external nares (openings that housed the nostrils), in contrast to H. typicus, where the tallest points are instead located beneath these openings. Part of the borders of the external nares are formed by the prefrontals (paired bones situated on the upper edges of the eye sockets). In H. altera, this configuration blocks the lacrimals (paired bones in front of the eye sockets) from forming part of the external nares, whereas the lacrimals do reach the external nares in H. typicus. A further difference between the two species lies in the shape of their lacrimals; in H. typicus, they are triradiate, while those of H. altera are massive and triangular.[1]
basioccipital (braincase bone to which the vertebral column attaches) bears a considerable amount of surface which is not involved in the joint between the skull and the spine.[3]
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.[3] 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.[1]
The
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.[3][1] These digits closely approach each other towards the tip of the limb.[1]
Classification
Both the original description by Maisch and the redescription of the English specimens found that Hauffiopteryx might be either a
