Rivista Italiana di Paleontologia e Stratigrafia (Research in Paleontology and Stratigraphy) vol. 127(2): 427-452. July 2021 A REVISION OF THE ANATOMY OF THE TRIASSIC PTEROSAUR AUSTRIADRACO DALLAVECCHIAI KELLNER, 2015 AND OF ITS DIAGNOSIS FABIO MARCO DALLA VECCHIA Institut Català de Paleontologia (ICP), Edifici ICP, Campus de la Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain. E-mail: [email protected] To cite this article: Dalla Vecchia F.M. (2021) - A revision of the anatomy of the Triassic pterosaur Austriadraco dallavecchiai Kellner, 2015 and of its diagnosis. Riv. It. Paleontol. Strat., 127(2): 427-452. Keywords: Pterosauria; anatomy; systematics; Alps; Norian. Abstract. Several skeletal elements preserved in the holotype and only specimen of the pterosaur Austriadraco dallavecchiai Kellner, 2015 (uppermost Triassic, Austria) have not been identified or have remained undescribed in previous works. They include important elements for the systematic and phylogenetic studies such as the femur, premaxillae and maxillary teeth. The broad bone initially considered the sternal plate is plausibly formed by the fused frontals, as already suggested by some authors. The diagnosis of Austriadraco dallavecchiai is amended on the basis of new information. The close relationship of Austriadraco dallavecchiai to Seazzadactylus venieri from the uppermost Trias- sic of Friuli (north-eastern Italy) is further supported by the morphological similarity between the two taxa (e.g. they share similar postorbital process of the jugal and dorsal process of the surangular). INTRODUCTION (Wellnhofer 2003). The specimen was first reported by Wellnhofer (2001, 2003), who noticed the pres- Pterosaurs are extinct archosaur reptiles of ence of the following skeletal elements: “isolated the Mesozoic and were the first vertebrates to evol- skull elements, both mandibular rami (incomplete) ve powered flight. Late Triassic (Norian, about 215 with teeth, a few isolated teeth, cervical, dorsal and million years ago) pterosaurs are the oldest ptero- caudal vertebrae, haemapophyses, ribs, gastralia, saurs found to date, and are represented by only a sternum, both scapulocoracoids, humeri, manual handful of specimens mainly found in the Alpine claws, a first wing phalanx, one half of the pelvis, region of Europe (Dalla Vecchia 2013). ?femur, tibia/fibula, ?metatarsals, pedal phalanges The early pterosaur Austriadraco dallavecchiai and many bone fragments of uncertain identity” Kellner, 2015 is based on a single specimen (BSP (Wellnhofer 2003: 8). Wellnhofer (2003) described 1994 I 51) found in 1994 in the middle-late Norian and figured the jugal (Wellnhofer 2003: fig. 3A); an Seefeld Formation along the western flank of the isolated “pseudo-unicuspid” tooth (fig. 4A) tenta- Karwendel Mountains in the Northern Calcare- tively identified as a mid-maxillary tooth or alterna- ous Alps near the town of Seefeld in Tyrol, Austria tively as a mandibular tooth 3; an isolated unicuspid tooth tentatively identified as a rostral premaxillary tooth (fig. 4B); two partial mandibular rami with Received: March 16, 2021; accepted: June 07, 2021 teeth (figs 5-8); cervical vertebrae (fig. 9); dorsal ribs 428 Dalla Vecchia F.M. and vertebrae (fig. 9A); a sternal plate (figs 9A and (preserved as an impression), the distal part of the 11A); some caudal vertebrae and haemapophyses left tibiotarsus, six metapodials tentatively referred (figs 9B and 10); the scapulocoracoids (figs 9A and as metatarsals, two small phalanges and an ungual 12); the left humerus (figs 9A, 13 and 14B); the right phalanx were described (Dalla Vecchia 2014: 90) wing phalanx 1 (fig. 15A); the right tibia (actually, a but not figured. The presence of a postorbital, part tibiotarsus) and fibula (fig. 15B); and a hemipelvis of the basicranium, two sclerotic ring elements, and (identified as the left one because of the purported a tarsal bone was also mentioned; however, these exposure of the acetabulum; fig. 16). A pedal un- elements were not figured nor described in detail, gual phalanx (see fig. 9B) is mentioned in the cap- because the declared intent of the author was to tion of his figure 9, but it is not described in the describe in detail specimen BSP 1994 I 51and name text. The whole specimen, preserved on “blocks a new taxon based on it in a different paper then I-V” (Wellnhofer 2003: 8), was also figured with an in progress (Dalla Vecchia 2014: 82-83). Dalla Vec- interpretive drawing (Wellnhofer 2003: fig. 2), but chia (2014: 82) referred specimen BSP 1994 I 51 as the small size of the image prevents the identifica- “genus and species to be named”, as it had already tion of the individual elements. The right humerus been done by Dalla Vecchia (2009a). (preserved as an impression only; Wellnhofer 2003: Based on BSP 1994 I 51, Kellner (2015) 15) and two incomplete wing phalanges tentatively erected the new genus and species Austriadraco dal- identified as wing phalanges 3 and 4 (Wellnhofer lavecchiai and created for it the monospecific Family 2003: 16) were summarily described but not fig- Austriadraconidae. Kellner (2015) did not identify ured. Some other elements were mentioned but or describe further skeletal elements or further fea- not described. They include “several fragments tures in the specimen BSP 1994 I 51 beyond those of skull bones” that are “only partly preserved, as described and figured by Wellnhofer (2003). Kell- impressions” on “blocks IV and V” and “are too ner’s only contribution to the osteology of BSP fragmentary for reliable identification” (p. 8); and 1994 I 51 was to identify as the fused frontals the fragmentary long bones on “block IV” that “are element that Wellnhofer (2003) had referred to a probably those of radius and ulna” (p. 15). The sternal plate (although this element is still reported gastralia, manual claws, ?femur, ?metatarsals, and as a sternum in Kellner 2015: fig. 2). However, the pedal phalanges listed on p. 8 are not mentioned identification as the fused frontals by Kellner was elsewhere in the text. Wellnhofer (2003: 7) referred based on Kellner’s personal observation as well as specimen BSP 1994 I 51 to Eudimorphodon cf. ranzii on the reference to the same identification made by Zambelli 1973. Bennett (2015: 801) (i.e. “Bennett in press”, Kell- In his monograph dedicated to the Triassic ner 2015: 676). The paper by Bennett (2015), which pterosaurs, Dalla Vecchia (2014) reported all of the had been submitted for publication before Kellner bones described by Wellnhofer (2003) and figured (2015) and still reported the specimen as ‘Eudimor- them (figs 4.1.32-45). The unicuspid isolated tooth phodon’ cf. ranzii, focused on the partial mandibular was identified as a one of the first and unicuspid rami of BSP 1994 I 51, confirming the previous mandibular teeth or a premaxillary tooth; the other identification by Nesbitt & Hone (2010) of the isolated tooth described by Wellnhofer (2003) was more complete ramus as a right element bearing a identified as a maxillary tooth but from a more me- lateral mandibular fenestra. Bennett (2015) identi- sial position with respect to that hypothesized by fied the “sternum” as the fused frontals in the gen- Wellnhofer (2003). A cervical vertebra, identified eral description of the specimen. by Wellnhofer (2003: 12) as a cervical 3 or 4, was Because of the publication by Kellner (2015), figured in detail (Dalla Vecchia 2014: fig. 4.1.37) Dalla Vecchia did not publish his in progress paper and reidentified as cervical 8. Five dorsal vertebrae mentioned in Dalla Vecchia (2014). Later, Dalla were reported (two more than in the description Vecchia (2018: fig. 3B) figured the postorbital and by Wellnhofer). The identification of the broad two sclerotic ring elements of BSP 1994 I 51. Fi- triangular bone as the sternal plate by Wellnhofer nally, Dalla Vecchia (2019: fig. 9C) figured the -ba (2003) was provisionally accepted, but the possibil- sicranium of BSP 1994 I 51 and highlighted the ity that it may actually be another skeletal element strict relationships between Austriadraco dallavecchiai was considered (Dalla Vecchia 2014: 88). A femur and the new taxon Seazzadactylus venieri. Revision of the pterosaur Austriadraco dallavecchiai 429 Comparison with the latter taxon now al- tologie und Geologie, Munich (Germany); BYU, Museum of Pale- lows the identification of some skeletal elements ontology, Brigham Young University, Provo (USA); MCSNB, Museo Civico di Scienze Naturali di Bergamo “E. Caffi”, Bergamo (Italy); of BSP 1994 I 51 that had remained indeterminate MFSN, Museo Friulano di Storia Naturale, Udine (Italy); MGUH, and permits us to revise the identification of some Geologisk Museum - Statens Naturhistoriske Museum, Københavns further elements. Universitet, Copenhagen (Denmark); MPUM, Museo Paleontologico Here, the skeletal elements of BSP 1994 I 51 del Dipartimento di Scienze della Terra, Università di Milano (Italy); SMNS, Staatliches Museum für Naturkunde Stuttgart (Germany). that have not been identified by Wellnhofer (2003) or Kellner (2015) nor have they been described and figured by these authors and by Dalla Vecchia SYSTEMATIC PALAEONTOLOGY (2014) are described and discussed. Furthermore, a revised diagnosis of Austriadraco dallavecchiai is pro- Diapsida Osborn, 1903 vided. Pterosauria Kaup, 1834 Unnamed clade in Dalla Vecchia, 2019 Austriadraco Kellner, 2015 MATERIALS, TERmiNOLOGY AND METHODS The holotype of Austriadraco dallavecchiai BSP 1994 I 51 is Austriadraco dallavecchiai Kellner, 2015 preserved on a limestone block that was broken into five fragments Figs 1-7A-D, 8-12 and 14B (numbered I to V, corresponding to blocks I-V of Wellnhofer 2003) and the counterslab of fragment IV. Fragment I contains only a small 2001 Eudimorphodon cf. ranzii - Wellnhofer, p. 100, figure at p. 100. piece of bone and is not shown in Figure 1. 2002 Eudimorphodon - Dalla Vecchia, p. 47. The specimen BSP 1994 I 51 was studied at the BSP using a 2003 Eudimorphodon cf. ranzii - Wellnhofer, p. 7, pp. 5-22, figs 2-3A, 4-11A, 12-14B, and 15-16, tab.