Aegirosaurus, Leptonectes, Hauffiopteryx, Suevoleviathan, Eurhinosaurus

Leptonectes tenuirostris (Conybeare 1822, Late Triassic to Early Jurassic) was a 'standard' ichthyosaur with a large skull and shorter fins. Notably the temporal bones wrapped around the back of the skull.

Hauffiopteryx typicus (von Huene, 1931 [originally Stenopterygius typicus], Maisch 2008, GPIT 1491/4; 1.93 m (6.3 ft); in length; early Toarcian, Early Jurassic) was a small ichthyosaur with a short, sharp snout. Eurhinosaurus is a sister taxon.

Aegirosaurus leptospondylus (Wagner 1853, Bardet and Fernandez 2000, originally Icthyosaurus leptospondylus, SM specimen, Late Jurassic, Solnhofen), is the neotype of a genus holotype destroyed in WW2. Here it nests with Hauffiopteryx not with Ophthalmosaurus. Note the enlarged prefrontals, as in Leptonectes, the reduced frontals and the crescent-shaped caudal fin preserving soft tissues.

Another specimen, JME-SOS-08369 mistakenly assigned by Delsett et al. 2022, nests with Mixosaurus.

Suevoleviathan disnteger (Originally Leptopterygius disinteger, Maish 1998; Lower Toarcian, Jurassic; SMNS 15390; 4m long). This specimen has jaws of equal length. The quadraotjugal was mislabeled in the drawing, corrected in the DGS tracing.

Suevoleviathan sp. (GPIT 328/4/5) nests with Suevoleviathan (above) despite the long rostrum/short mandible morphology here not shown in the type.

Eurhinosaurus longirostris (Abel 1909, Early Jurassic, Sinemurian - Toarcian, 6m) Derived from a sister to Leptonectes, Eurhinosaurus was larger, more gracile, had a smaller skull and larger tail and fins. The mandible was much smaller than the rostrum. The tooth length was patterned in three lengths.

Abel O. 1909. Cetaceenstudien. 1. Mitteilung: Das Skelett von Eurhinodelphis cocheteuxi
aus dem Obermiozän von Antwerpen. Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Klasse, 118:241–253.

Bardet N and Fernández M 2000. A new ichthyosaur from the Upper Jurassic lithographic limestones of Bavaria. Journal of Paleontology. 74(3): 503–511.

Conybeare WD 1822. Additional notes on the fossil genera Ichthyosaurus and Plesiosaurus. Transactions of the Geological Society of London (2)1:103-123.

Maisch MW 1998. A new ichthyosaur genus from the Posidonia Shale (Lower Toarcian, Jurassic) of Holzmaden, SW-Germany with comments on the phylogeny of post-Triassic ichthyosaurs. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 209: 47–78.

Maisch MW 2008. Revision der Gattung Stenopterygius Jaekel, 1904 emend. von Huene, 1922 (Reptilia: Ichthyosauria) aus dem unteren Jura Westeuropas. Palaeodiversity 1: 227–271.

wiki/Hauffiopteryx
wiki/Eurhinosaurus
wiki/Leptonectes
wiki/Suevoleviathan
wiki/Aegirosaurus