[Paleontology • 2022] Quadrupedal Water Launch Capability Demonstrated in Small Late Jurassic Pterosaurs

in Pittman, Kaye, Campos & Habib, 2022. 

DOI: 10.1038/s41598-022-10507-2

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Artwork by Julius T. Csotonyi

Abstract

Pterosaurs thrived in and around water for 160 + million years but their take-off from water is poorly understood. A purportedly low floating position and forward centre of gravity barred pterosaurs from a bird-like bipedal running launch. Quadrupedal water launch similar to extant water-feeding birds and bats has been proposed for the largest pterosaurs, such as Anhanguera and Quetzalcoatlus. However, quadrupedal water launch has never been demonstrated in smaller pterosaurs, including those living around the Tethys Sea in the Late Jurassic Solnhofen Lagoon. Using Laser-Stimulated Fluorescence, we singled out aurorazhdarchid specimen MB.R.3531 that alone preserved specific soft tissues among more than a dozen well-preserved Solnhofen pterosaur specimens. These soft tissues pertain to primary propulsive contact surfaces needed for quadrupedal water launch (pedal webbing and soft tissues from an articulated forelimb) that permit robust calculations of its dynamic feasibility without the need to make assumptions about contact areas. A first-principles-based dynamics model of MB.R.3531 reveals that quadrupedal water launch was theoretically feasible and that webbed feet significantly impacted launch performance. Three key factors limiting water launch performance in all pterosaurs are identified, providing a foundation for understanding water launch evolution: available propulsive contact area, forelimb extension range and forelimb extension power about the shoulder.

Skeleton and associated soft tissues of the aurorazhdarchid pterosaur specimen MB.R.3531a.
 (a) White light image of slab. Scale = 20 mm. (b) LSF image of slab.
Soft tissues visible under white light are clearer under LSF, whilst speculative soft tissues under white light are confirmed by the technique. Otherwise invisible soft tissues are also revealed under LSF.  

 

Michael Pittman, Thomas G. Kaye, Hebert B. Campos and Michael B. Habib. 2022. Quadrupedal Water Launch Capability Demonstrated in Small Late Jurassic Pterosaurs. Scientific Reports. 12: 6540. DOI: 10.1038/s41598-022-10507-2

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[Paleontology • 2017] The Taxonomy and Phylogeny of Diopecephalus kochi (Wagner, 1837) and ‘Germanodactylus rhamphastinus’ (Wagner, 1851)

Altmuehlopterus Vidovic & Martill, 2017

Altmuehlopterus rhamphastinus  (Wagner, 1851)

Fig. 2. ‘Germanodactylus rhamphastinus’ – photographs and interpretative drawings of the slabs (a) BSP AS I 745 b and (b) BSP AS I 745 a. Abbreviations: pc, premaxillary crest; st, sternum.

twitter.com/GeolSoc DOI:  10.1144/SP455.12

The Solnhofen pterosaurs Pterodactylus antiquus, Aerodactylus scolopaciceps, Diopecephalus kochi, Germanodactylus cristatus and Germanodactylus rhamphastinus all have complicated taxonomic histories. Species originally placed in the genus Pterodactylus, such as Aerodactylus scolopaciceps, Ardeadactylus longicollum, Cycnorhamphus suevicus and Germanodactylus cristatus possess apomorphies not observed in the type species of Pterodactylus, and consequently have been placed in new genera. The affinities of another Solnhofen pterosaur previously placed in Pterodactylus, Diopecephalus kochi, are less clear. It has been proposed that D. kochi is a juvenile specimen of Pterodactylus antiquus, or perhaps ‘Germanodactylus rhamphastinus’ specimens are mature examples of D. kochi. Furthermore, studies have suggested that ‘Germanodactylus rhamphastinus’ is not congeneric with the type species of Germanodactylus. Geometric morphometric analysis of prepubes and a cladistic analysis of the Pterosauria elucidate plesiomorphic and apomorphic conditions for basal Jurassic pterodactyloids. Germanodactylus is found to be a monotypic genus and Pterodactylus, Diopecephalus, and ‘G. rhamphastinus’ are found as distinct taxa belonging in individual genera, diagnosable using a combination of characters. Thus, Diopecephalus kochi is not demonstrated to be congeneric with Germanodactylus or Pterodactylus and is maintained as a valid taxon. ‘G. rhamphastinus’ is readily distinguishable from other Solnhofen pterosaur taxa, and a new genus is erected for its reception.

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Altmuehlopterus gen. nov.

Derivation of name. ‘Altmuehl’ refers to the Altmühl river that flows through Solnhofen (close to Mörnsheim), Eichstätt and joins the river Danube at Kelheim. ‘Pterus’ is a common suffix in pterosaur names referring to the wing. This name is presented as an alternative to the geographically significant name Daitingopterus (Maisch et al., 2004) which is a nomen nudum. 

Type species: Altmuehlopterus rhamphastinus (Wagner, 1851) 

Fig. 3. Germanodactylus cristatus – (a) a photograph of most of the skeleton on the slab and (b) a line drawing of the skull of the holotype BSP 1892 IV 1.

Fig. 10. Cranial characters and prepubes of Franconia laminated limestone pterosaurs plotted onto a pruned tree. The tree is plotted against the ‘fine scale’ dating criteria of the Franconia laminated limestones (Schweigert 2007).

Steven U. Vidovic and David M. Martill. 2017. The Taxonomy and Phylogeny of Diopecephalus kochi (Wagner, 1837) and ‘Germanodactylus rhamphastinus’ (Wagner, 1851). Geological Society, London. Special Publications. (2017); SP455.12. DOI: 10.1144/SP455.12

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