A new specimen of Palvennia hoybergeti : implications for cranial and pectoral girdle anatomy in ophthalmosaurid ichthyosaurs

• Published in: PeerJ (San Francisco, CA) Vol. 6; p. e5776
• Main Authors: Delsett, Lene Liebe, Druckenmiller, Patrick Scott, Roberts, Aubrey Jane, Hurum, Jørn Harald
• Format: Journal Article
• Language: English
• Published: United States PeerJ. Ltd 12.10.2018; PeerJ, Inc; PeerJ Inc
• Subjects: Evolutionary Studies; Geology; Ichthyosauria; Ichthyosaurs; Late Jurassic; Marine Biology; Museums; Ophthalmosauridae; Paleontology; Pectoral girdle; Phylogeny; Physiological aspects; Principal components analysis; Reptiles & amphibians; Shoulder girdle; Skull; Spitsbergen; Stratigraphy; Taxonomy; Vertebrates; Zoology; United States > US; Norway; Spitsbergen; Ichthyosauria; Pectoral girdle; Skull; Ophthalmosauridae; Late Jurassic; PCA; Palvennia hoybergeti
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.5776

The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marine reptiles, including four named taxa of ophthalmosaurid ichthyosaurs. One of these, , is based on the single holotype specimen (SVB 1451) with an incomplete skull. A newly discovered specimen (PMO 222.669) with a disarticulated but largely complete skull and anterior postcranium is described, which considerably expands our knowledge of this taxon. Two additional new ophthalmosaurid specimens with pectoral girdles from the same member are described. The taxonomic utility of the ophthalmosaurid pectoral girdle is contentious, and an assessment of seven pectoral girdles from the Slottsmøya Member provides a basis for addressing this question via a 2D landmark principal component analysis of baracromian coracoids. The analysis reveals a taxonomic signal in the coracoids but also highlights the degree of individual variation. Commonly used phylogenetic characters do not fully encapsulate the degree of variation seen in coracoids and in some cases combine analogous features.