Figure 1

Ammonoid biostratigraphy of Spathian (Olenekian, Lower Triassic) ichthyopterygian and possible ichthyopterygian fossil localities. Ammonoid biostratigraphic data were compiled after Ji et al.⁷ for Chaohu (South China); Tongtherm et al.⁵ for Phatthalung (Thailand); Zakharov et al.^20,22 and Shigeta and Kumagae⁷³ for South Primorye (Russia); Bando and Shimoyama⁵⁹, Ehiro et al.⁶¹, Shigeta and Nakajima²⁹, and Shigeta⁶⁰ for Kitakami (Northeast Japan); Hurum et al.¹¹ and Hansen et al.¹² for Svalbard (Norway); Guex et al.⁵⁶ and Brayard et al.⁵⁵ for the Western United States; Tozer⁵⁷ for British Columbia (Canada). Ichthyopterygian horizons are also compiled after Ji et al.⁷ for Chaohu; Tongtherm et al.⁴ for Phatthalung; Shikama et al.³² for Kitakami; Maxwell and Kear¹⁰, Hurum et al.¹¹, Hansen et al.¹⁷, Engelschiøn et al.¹⁸, and Ekeheien et al.¹⁶ for Svalbard; Massare and Callaway¹⁴, Scheyer et al.², Kelley et al.¹⁵, Smith et al.³ for Western USA; Brinkman et al.³⁸ and Cuthbertson et al.^12,39 for British Columbia. Silhouettes indicate the occurrence of ichthyopterygian fossils. Possible source of materials without reliable ammonoid biostratigraphic information is indicated with a question mark. Taxonomic names are given in generic or higher rank with approximate body length when available. Asterisks indicate disputed taxa. The Grippia Niveau is likely from either Bajarunia euomphala or Parasibirites grambergi zone.