Evidence of large terrestrial seymouriamorphs in the lowermost Permian of the Czech Republic

Abstract

Lower Permian strata of the Boskovice Basin in the Czech Republic have yielded hundreds of largely complete seymouriamorph individuals, some of which are exceptionally preserved and have noticeable soft tissues, such as external gills and eye structures. The vast majority of these finds are referable to Discosauriscus austriacus, and almost exclusively represent larvae and juveniles tied to aquatic environments. Only one of the specimens discovered to date has been interpreted as an early adult, although late juvenile and early sub‐adult stages have been proposed for it as well. Regardless, no other seymouriamorph adults have been reported from the Boskovice Basin so far. Here we present the first comprehensive assessment of seymouriamorph tracks and a trackway from the Asselian (lowermost Permian) of the Boskovice Basin. The morphology of the tracks is congruent with that of the ichnotaxon Amphisauropus and indicates an attribution to Discosauriscidae or that they belong to as yet unrecognized large seymouriamorphs. All tracks were made by individuals much larger than the largest discosauriscid known from bodily preserved material and are interpreted as those of adults tied to terrestrial environments, thus apparently documenting a habitat shift that occurred relatively late in the ontogenetic development of these seymouriamorphs. Furthermore, the largest track is preserved in extraordinary detail and includes soft part impressions such as digital, palmar and plantar flexion creases, making the specimen one of the best preserved seymouriamorph tracks described to date. Finally, one of the tracks originates from the lowermost Asselian and is therefore among the oldest known records of seymouriamorphs worldwide.

Synapsid tracks with skin impressions illuminate the terrestrial tetrapod diversity in the earliest Permian of equatorial Pangea

“…The terrestrial faunal components of Permian age of the Boskovice Basin are essentially unknown. However, recent fieldwork conducted in the Asselian strata at various localities situated within the basin has yielded diverse assemblage of tetrapod tracks and trackways that have been made by terrestrial tetrapods 5,16,17 .Here we report a new assemblage of tracks of varying degrees of preservation originating from three localities of the Letovice and Padochov formations, which can be attributed to the ichnotaxon Dimetropus. The specimens…”

“…It is worth noting that other lower Permian material from the Lubě Horizon has been discovered with wellpreserved soft part impressions as well; this material has been attributed to the seymouriamorph ichnotaxon Amphisauropus and shows digital, palmar, and plantar flexion creases (see Ref. 5 ).…”

“…Discosauriscids have been unearthed from several horizons within the basin (e.g., Ref. 5 , Fig. 2 ).…”

“…The terrestrial faunal components of Permian age of the Boskovice Basin are essentially unknown. However, recent fieldwork conducted in the Asselian strata at various localities situated within the basin has yielded diverse assemblage of tetrapod tracks and trackways that have been made by terrestrial tetrapods 5 , 16 , 17 .…”

Corrigendum

“…In the referenced article, Calábková et al . (2022), figure 1 was published with two areas erroneously indicated as ice:

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