Abstract The taxonomy of the Late Jurassic pterodactyloid pterosaur Pterodactylus scolopaciceps Meyer, 1860 from the Solnhofen Limestone Formation of Bavaria, Germany is reviewed. Its nomenclatural history is long and complex, having been synonymised with both P. kochi (Wagner, 1837), and P. antiquus (Sömmerring, 1812). The majority of pterosaur species from the Solnhofen Limestone, including P. scolopaciceps are represented by juveniles. Consequently, specimens can appear remarkably similar due to juvenile characteristics detracting from taxonomic differences that are exaggerated in later ontogeny. Previous morphological and morphometric analyses have failed to separate species or even genera due to this problem, and as a result many species have been subsumed into a single taxon. A hypodigm for P. scolopaciceps, comprising of the holotype (BSP AS V 29 a/b) and material Broili referred to the taxon is described. P. scolopaciceps is found to be a valid taxon, but placement within Pterodactylus is inappropriate. Consequently, the new genus Aerodactylus is erected to accommodate it. Aerodactylus can be diagnosed on account of a unique suite of characters including jaws containing 16 teeth per-jaw, per-side, which are more sparsely distributed caudally and terminate rostral to the nasoantorbital fenestra; dorsal surface of the skull is subtly depressed rostral of the cranial table; rostrum very elongate (RI = ∼7), terminating in a point; orbits correspondingly low and elongate; elongate cervical vertebrae (approximately three times the length of their width); wing-metacarpal elongate, but still shorter than the ulna and first wing-phalanx; and pteroid approximately 65% of the total length of the ulna, straight and extremely thin (less than one third the width of the ulna). A cladistic analysis demonstrates that Aerodactylus is distinct from Pterodactylus, but close to Cycnorhamphus Seeley, 1870, Ardeadactylus Bennett, 2013a and Aurorazhdarcho Frey, Meyer and Tischlinger, 2011, consequently we erect the inclusive taxon Aurorazhdarchidae for their reception.

Citation: Vidovic SU, Martill DM (2014) Pterodactylus scolopaciceps Meyer, 1860 (Pterosauria, Pterodactyloidea) from the Upper Jurassic of Bavaria, Germany: The Problem of Cryptic Pterosaur Taxa in Early Ontogeny. PLoS ONE 9(10): e110646. https://doi.org/10.1371/journal.pone.0110646 Editor: Peter Dodson, University of Pennsylvania, United States of America Received: April 14, 2014; Accepted: September 9, 2014; Published: October 22, 2014 Copyright: © 2014 Vidovic, Martill. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. All relevant data are within the paper and its Supporting Information files. Funding: SUV received a small grant to visit the natural history museum in Basel, in aid of this project. The funding was provided by the Systematics Association and Linnean Society, London, through the “Systematics Research Fund” http://www.systass.org/awards/srf11-12results.shtml. No funds were provided for publication costs. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist.

Discussion Linear measurements of specimens assigned to P. antiquus [2] were compared in a series of graphical analyses, to demonstrate how well supported two morphotypes contained within the hypodigm are. In these graphical analyses there is consistently strong support for the relationship between specimens referred to morphotype two. The taxonomic relationship among specimens of morphotype one was not as well supported as morphotype two, but the morphotype one assemblage is found to be distinct from morphotype two. There were some instances of strong support for a relationship among all specimens, but equally, the results frequently demonstrated no relationship for all the specimens collectively. From these analyses it is clear that morphotype two is a valid species, referable to “P. scolopaciceps”. Both morphotypes one and two share affinities with P. antiquus, but neither display consistent relationships with this taxon, therefore “P. scolopaciceps” is unlikely to be congeneric with Pterodactylus. The distinguishing features of “P. scolopaciceps”, as demonstrated by these analyses, are the shape and length of the skull, the elongation of the cervical vertebrae, and a relatively small pes when compared to other pterodactyloids of a similar size. These features are not restricted to one morphological unit, and suggest that “P. scolopaciceps” occupied a different ecological niche to P. antiquus and the specimens studied as morphotype one. We suggest that the elongate metacarpal is consistent with wading, whilst the long neck and rostrum are conducive to low level feeding. Therefore, “P. scolopaciceps” was possibly a wading pterosaur, occupying a similar ecological niche to the modern Snipe, although we consider it likely that ecological niches changed through ontogeny. Further examination of the taxonomic validity of “P. scolopaciceps” using cladistic methods confirms that it is not congeneric with P. antiquus. “P. scolopaciceps” and its sister taxon Gladocephaloideus are found at the base of a monophyletic clade also containing Cycnorhamphus, Aurorazhdarcho and Ardeadactylus, but not P. antiquus. “P. scolopaciceps” is distinguished from Gladocephaloideus and Cycnorhamphus by a more extensive dentition (skull length occupied by the dentition: Gladocephaloideus ∼20%; Cycnorhamphus ∼7%; “P. scolopaciceps” ∼45%) and a less depressed dorsal slope to the skull, which is more similar to that of Ardeadactylus. Indeed, ontogenetically variable features, such as the angle of the quadrate to the dental margin may be all that separates “P. scolopaciceps” from Ardeadactylus in our cladistic analysis. However, both Ardeadactylus and Aurorazhdarcho are distinct from “P. scolopaciceps” in the proportions of the wing metacarpal to other wing elements. In both Ardeadactylus and Aurorazhdarcho the wing metacarpal (MCIV) exceeds the ulna (ulna is 79% and 87% of MCIV length respectively), but is shorter than the first wing phalanx (WPh1) (MCIV is 83% and 79% of WPh1 length respectively). In “P. scolopaciceps” the wing metacarpal is shorter than the ulna and first wing phalanx (Fig. 2A), which is true of all size classes studied. Moreover the gradient of the regression line comparing these elements suggests that the wing metacarpal would never exceed the ulna in length. Furthermore specimens of “P. scolopaciceps” lack the small bony triangular headcrest present on Ardeadactylus, which is also referred to Aurorazhdarchidae fam. nov., although this could be ontogenetically variable. “P.” scolopaciceps also has a curved humeral shaft, and a narrow, spatulate prepubis that is similar to Pterodactylus, clearly distinguishing it from Cycnorhamphus, Ardeadactylus and Aurorazhdarcho. Aurorazhdarcho [6] is distinct from Ardeadactylus [2] in the extent of contact between the ischium and pubis, the sternal morphology and the gracility of its bones (ulna length/width quotient- Ardeadactylus = 14; Aurorazhdarcho = 21). In the very first cladistic analysis of the Pterosauria, Howse [43], using only characters from cervical vertebrae, found a polytomic grouping of taxa that approximates the Azdarchidae of Unwin [46]. He also found Pterodactylus kochi to form a polytomy with Pterodactylus elegans ( = Ctenochasma elegans) at the base of Pterodactyloidea, whereas P. antiquus fell into a polytomy with P. longicollum ( = Ardeadactylus) in a more crownward position (Fig. 14). Since then, Unwin [33] combined P. antiquus and P. kochi into a single taxonomic unit, which fell into a polytomy with Lonchodectidae and Ctenochamatidae. Concurrently Kellner [26] analysed P. antiquus and P. kochi as separate taxonomic units, and found that together they formed a polytomy with Germanodactylus, noting that there is no synapomorphy to unite the two Pterodactylus species with each other relative to Germanodactylus. More recently, Wang et al. [41] found the same relationship as in Kellner [26]. However, Lü et al. [30] found that Pterodactylus formed a polytomy with Cycnorhamphus and Gnathosaurinae + Ctenochasmatinae in Ctenochasmatoidea. We suggest that the failure to resolve this polytomy may in part lie in the combining of two distinct taxa within Pterodactylus. In the cladistic analysis presented here we analysed the holotype specimens of Pterodactylus antiquus (BSP AS I 739); P. kochi (SMF R 404/BSP AS XIX) and “P. scolopaciceps” (BSP AS V 29 a/b). In addition we coded some characters for “P. scolopaciceps” from specimen BSP 1937 I 18 described by Broili [17] due to the poor preservation of the holotype. As a consequence of our analyses we place “P. scolopaciceps” in the new genus Aerodactylus gen. nov. urn:lsid:zoobank.org:act:D7B8AA15-6742-4BE3-B030-9CECA966086E. PPT PowerPoint slide

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larger image TIFF original image Download: Figure 14. Cladograms based on the results of a cladistic analysis by Howse Cladograms based on the results of a cladistic analysis by Howse [43] Pterodactylus elegans = Ctenochasma elegans; Pterodactylus micronyx = Aurorazhdarcho micronyx; Gallodactylus = Cycnorhamphus; Pterodactylus longicollum = Ardeadactylus longicollum; Doratorhynchus = Pterodactyloidea incertae sedis. (?azhdarchid?); Titanopteryx = Arambourgiana; Greensand long cervical vertebrae = no specimen number or reference given. https://doi.org/10.1371/journal.pone.0110646.g014

Systematic Palaeontology PTEROSAURIA Kaup, 1834 [47] MONOFENESTRATA Lü et al., 2010 [45] PTERODACTYLOIDEA Plieninger, 1901 [31] AURORAZHDARCHIDAE fam. nov. AERODACTYLUS gen. nov. Fig. 1 and Fig. 3F Type species Aerodactylus scolopaciceps (Meyer, 1860 [8]). Content The type species Aerodactylus scolopaciceps gen. nov. is the only species currently contained in Aerodactylus. Diagnosis As for type and only species. Etymology Aero = wind (Greek) + dactylus = finger (Greek), a common suffix in pterosaur names. The name derives from the Nintendo Pokémon Aerodactyl, a fantasy creature made up of a combination of different pterosaurian features. It seemed a pertinent name for a genus which has been synonymous with Pterodatylus for so long due to a combination of features. Synonymy 1850 Pterodactylus longirostris Meyer, p. 199 [48] When Meyer originally described the specimen he referred it to what is now known as Pterodactylus antiquus 1860 Pterodactylus scolopaciceps Meyer, p. 33 [8] 1883 Pterodactylus kochi (H. v. Meyer) Zittel p. 25 [14] 1901 Pterodactylus scolopaciceps von Meyer; Seeley p. 105 [49] 1938 Pterodactylus scolopaciceps H. v. Meyer; Broili p. 146 [17] 1970 Pterodactylus scolopaciceps H. v. Meyer, 1850; Wellnhofer p.22 [15] 1970 Pterodactylus kochi Wagner, 1837; Wellnhofer p. 22 [15] Holotype BSP AS V 29 a/b: part and counterpart, with a complete skeleton of a small juvenile. Referred material BSP 1883 XVI 1 (Fig. 2Bi, ii and 3D) and counterpart MCZ 1505: a complete skeleton of a large individual. BSP 1975 I 221: a complete skeleton on a slab, in left lateral view. BSP 1937 I 18 (Fig. 2A and 3E): a complete specimen with soft tissue, in dorsal and right lateral view. Example of Frey & Martill [20]: a complete specimen with soft tissue in right lateral view. NHMW 1975/1756: part and counterpart, a complete skeleton with soft tissue. Locality and horizon Solnhofen Limestone, Malm Zeta 2, Solnhofen, Bavaria, Germany. Diagnosis (None of the following are autapomorphies, but together form a unique combination of characters) A pterodactyloid pterosaur with elongate cervical vertebrae (approximately three times longer than they are wide at the mid-centrum corpus). The rostrum is very elongate (RI = ∼7), terminating in a point, making the upper and lower jaws superficially like the beak of a Eurasian Woodcock. The jaws contain 16 teeth per-jaw, per-side, which are more sparsely distributed caudally (tooth spacing is equal to adjacent tooth width mesially, and up to four times adjacent tooth width distally) and terminate rostral to the nasoantorbital fenestra. Dorsal surface of skull concave, subtly depressed rostral to the cranial table. Orbit low and elongate (more than one and a half times longer than it is deep). Wing-metacarpal elongate, but shorter than both ulna and first wing-phalanx. The pteroid is approximately 65% of the total length of the ulna, straight and extremely thin (length is greater than ten times its width, and it is less than one third the width of the ulna). The humeral shaft is slightly bowed, curving cranially, just anconal of the midsection. The plate of the prepubis gradually sweeps away from the scapus, the lateral extremity of the plate is angular (∼90°), and the distal edge is sub-rounded (as in P. antiquus). Taxonomic Remarks Although PTH 1962.148 demonstrates similar proportions and morphologies to Aerodactylus gen. nov. it possesses a straight humeral shaft and a bowed pteroid. It is possible that this example is a juvenile of Ardeadactylus. This suggestion is supported by the presence of a very small bony crest dorsal to the frontals and caudal to the parietals, perhaps an anchoring point for a more extensive soft tissue crest. The separation of the pubis and ischium suggests a possible affinity with Ardeadactylus (personal observations), although it is more likely due to early ontogeny. The wing metacarpal of PTH 1962.148 is short relative to its ulna, which is not consistent with Ardeadactylus. The “P. micronyx” specimens assigned to Aurorazhdarcho have long wing metacarpals, suggesting that the proportions of the ulna and wing metacarpal do not change significantly through ontogeny.

Anatomical Description Cranial skeleton The cranial anatomy of Aerodactylus scolopaciceps gen. nov. is typified by an elongate orbit and skull, with a subtle depression in the dorsal surface of the rostrum. The premaxilla is fused to the maxilla even in the smallest juvenile (BSP AS V 29a/b), making it difficult to tell where the maxilla starts. Dorsal to the nasoantorbital fenestra the premaxilla extends caudally to the caudal third of the orbit. The distal tip of the premaxilla has a convex profile, caudal of the first two teeth the rostrum is sub-parallel. The four most mesial teeth are tentatively identified as the premaxillary dentition, which consists of simple conical teeth. In the premaxilla of BSP 1937 I 18 the caudal two teeth exhibit a tumescence in the cervical region of the crown, however this may be a taphonomic feature caused by the expansion of infilling minerals in the pulp cavity. The teeth in the premaxilla and the mesial maxillary teeth are perpendicular to the jaw margin, but the shorter crowns of the distal most teeth are slightly procumbent, whereas all the teeth in the dentary are slightly procumbent. The majority of the dentition is nearly isodont, but the four distal teeth are up to two and a half times smaller than the larger teeth. In the mesial part of the jaw, the distance between teeth is approximately equal to the adjacent tooth width, but distally the gaps become much greater, up to four times the width of the adjacent tooth. Tooth spacing is approximately equal to the adjacent tooth width in the mesial part of the jaw, but distally the gaps become much greater. The dentition terminates immediately rostral to the nasoantorbital fenestra vacuity. The vacuity of the nasoantorbital fenestra is significantly less than a third of the total length of the premaxilla. Rostral to the nasoantorbital fenestra a thin sheet of maxillary bone occupies the space between the caudal process of the premaxilla and caudal, dentulous portion of the caudal process of the maxilla. The maxilla extends half the length of the nasoantorbital fenestra vacuity, contacting the ventral margin of the splint-like jugal maxillary process. The ventral margin of the maxilla is slightly concave with the distal procumbent teeth projecting into the void, but the ventral margin of the maxilla and premaxilla appears straight. The jugal is very elongate and slender, with the dorsal lacrimal process (DLPJ) displaced rostral, relative to the ventral apex. Compared to the rest of the jugal, the DLPJ is very broad at its base (approximately twice the breadth of the maxillary and caudal processes). The ventral apex of the jugal curves ventrally, to form a smooth sweeping curve with the quadratojugal, terminating at the articular process of the quadrate. The caudal process of the jugal extends to the caudal margin of the infratemporal fenestra, where it contacts the postorbital and possibly a postfrontal, which is unclear and poorly defined in all specimens. The quadratojugal is a short rectangular bone, located at the anteroventral margin of the infratemporal fenestra. Adjacent to the quadratojugal, the quadrate is slender and elongate, extending caudally to the occipital region of the skull, caudal to the orbit. The long axis of the quadrate lies at approximately 170 degrees to the dental plane of the upper jaw. The infratemporal fenestra is bounded on its ventral margin by the quadrate. The infratemporal fenestra lies entirely beneath the orbit, with a poorly defined mass of bone comprising the postorbital and squamosal behind it. The supratemporal fenestra is located caudal to the infratemporal fenestra in the ventral portion of the skull. The squamosals, parietals and frontals form a smooth, rounded cranium, meeting the premaxilla and nasals above the orbit. The nasals underlie the premaxilla and extend approximately half way into the nasoantorbital fenestra vacuity. The descending process of the nasal descends steeply and is long, but does not reach the maxilla. In BSP 1937 I 18 elements of the palate have been displaced into the nasoantorbital fenestra and orbit, tentatively identified here as the pterygoids and ectopterygoids. The lacrimal meets the dorsal process of the jugal, separating the orbit and nasoantorbital fenestra. The dorsal half of the lacrimal is as broad as the ventral part of the DLPJ, but there is a distinctive step making it considerably thinner ventrally (a quarter of the width of the dorsal portion). Due to the step in the lacrimal the orbit is low and long, with a length just over one and a half times its depth. The lower jaw is similar in morphology to the anterior portion of the rostrum, becoming gradually more robust caudally (three and a half times deeper than the anterior part). The mandible is approximately straight along almost its entire length, only curving ventrally immediately rostral to the retroarticular process. The retroarticular process is short, broad (equal length and depth), wedge-like and in line with the sweep of the jaw. There is no intramandibular ridge of the splenial preserved in the specimens studied, but it is suggested to have been present to some extent considering its extensive presence in both Ardeadactylus and Cycnorhamphus [50] which share a close common ancestor to Aerodactylus gen. nov. Postcranial skeleton Axial skeleton. The axial skeleton is typified by a long cervical series, consisting of elongate cervical vertebrae (cervical vertebra five, three times the length of its width), followed by a comparitively short PCRW and a short tail (for a pterodactylioid). There are 7–8 cervical vertebrae. The eighth ?cervical vertebra is half the length of the seventh and located between the scapulae, but it has a similar morphology to the other cervical vertebrae. However, the first dorsal rib is not clearly preserved, leaving some ambiguity over the identification of an eighth cervical vertebra. The cervical vertebrae are typically procoelous and lack cervical ribs. The neural spines of the cervical vertebrae are very low and long (at least ten times longer than they are tall), and the neural spine of the axis is indistinct. The cervical centra are constricted slightly caudal to the craniocaudal centre when seen in dorsal view, from this point the pre-exapophyses and postexapophyses project cranio/caudolaterally from the centrum corpus. The pre-exapophyses are more elongate than the postexapophyses. The dorsal vertebrae are 1.5–2 times longer than wide. The neural spines are taller than they are long and perpendicular to the centrum. The specimens lack a notarium, and lack fusion between vertebral centra, although this could be due to the juvenile condition of the specimens studied. The thoracic ribs are poorly preserved and it is difficult to distinguish the articular ends proximal to the vertebrae. There are four sacral vertebrae with transverse processes fused to the iliac blade. Caudal of the sacral vertebrae there are 15 small caudal vertebrae which together are approximately two thirds the length of the femur, and ∼15% of the total vertebral column length. Appendicular skeleton. The sternum is not well preserved in any specimens that can be confidently assigned to Aerodactylus gen. nov. (PTH 1962.148 has a similar sternum morphology to P.antiquus). The scapula and coracoid are unfused, possibly due to the specimens studied not being fully mature. The scapula extends caudally, and is elongate, spatulate with a deflection proximal to the glenoid fossa. The coracoid is very broad proximal to the glenoid (Fig. 15), as in Cycnorhamphus, Aurorazhdarcho and Ardeadactylus. The humeral shaft is slightly bowed cranially (it is straight in Cycnorhamphus, Ardeadactylus and Aurorazhdarcho), the deltopectoral crest continuously sweeps from the shaft towards the humeral head. The deltopectoral crest is approximately equal in width to the humeral head, and is rounded at its cranial end. The caudal margin of the humerus is somewhat sigmoidal along its length due to a slightly flared humeral head proximally and an exaggerated flexure of the distal condyles in the opposite direction. The medial and lateral epicondyles of the humerus are approximately equal in size. PPT PowerPoint slide

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larger image TIFF original image Download: Figure 15. A private specimen of Aerodactylus demonstrating the shoulder girdle morphology. A) A photograph of a private specimen, which plots onto all graphs on the regression line belonging to morphotype two, thus is identified as Aerodactylus scolopaciceps gen. nov. The area of the photograph illustrates the morphology of the coracoid and humerus. The humerus is more similar to that of Aurorazhdarcho, but the proportions of the wing metacarpal are similar to Aerodactylus scolopaciceps gen. nov. B) Interpretive line diagram: co, coracoid; cv, cervical vertebra; hu, humerus; pt, pteroid; ra, radius; sc, scapula; ul, ulna; wph1, wing-phalanx one; wph2, wing-phalanx two. Scale bar = 10 mm. https://doi.org/10.1371/journal.pone.0110646.g015 The ulna and radius are almost equal in width, and approximately three times the length of the humerus. There are no detectable muscle scars, proximal tubercle of the radius, or olecranon process of the ulna. The pteroid is approximately 65% of the total length of the ulna and extremely thin, lacking the proximal curvature seen in Pterodactylus antiquus. The pteroid length is an autapomorphy of Aurorazhdarchidae fam. nov. with Aerodactylus gen. nov., Cycnorhamphus and Aurorazhdarcho sharing a straight pteroid, compared to the sigmoidal pteroid of Ardeadactylus. The wing metacarpal is elongate, but does not exceed the length of the ulna, and the growth allometry of the sampled specimens suggests that adult specimens would maintain this condition. The first wing phalanx is ∼20% longer than the wing metacarpal but fractionally (1–2%) shorter than the ulna. The second wing phalanx is approximately the same length, or slightly (∼1%) shorter than the first, the third is 85% of the total length of wing phalanx one, and the fourth is 70% the total length of wing phalanx one. The first three wing phalanges are straight, while the fourth phalanx has a slight caudal curvature. The manus compares favourably with that of Pterodatylus, but not with Aurorazhdarcho. The pelvis is poorly preserved in the majority of specimens. The preacetabular process is a straight, elongate semicircle. The postacetabular process is a short, posterodorsally directed process. It is not possible to tell if the pubis is completely fused to the ischium as in Aurorazhdarcho, or if it is a largely distinct process as in Ardeadactylus. The prepubis consists of an elongate scapus, smoothly sweeping out to a broadly symmetrical plate. The prepubic plate is angular at its lateral margin and rounded on its distal margin. The femur is slightly bowed caudally and is approximately 65% of the total tibia length. The tibia is long and straight. The fibula has not been detected. It is also hard to distinguish the tarsals, due mainly to crushing and calcite crystal mineralization on the distal end of the tibia. The middle phalanges of pedal digit four are square, and the proximal phalanx exceeds the length of the distal phalanx. The pedal unguals are significantly (40%) smaller than those of the manus. The fifth pedal digit consists of a single small phalanx, less than half the size of the robust fifth metatarsal. Soft tissue. Soft tissues are preserved in several pterosaur specimens from the Solnhofen Limestone Formation, and have been detected in both Pterodactyloidea and Rhamphorhynchidae [12], [13], [14], [15], [16]. These include wing membranes, integument and integumentary structures and soft tissue head crests (Fig. 2). For a detailed description of the soft tissue of Aerodactylus scolopaciceps gen. nov. refer to Wellnhofer [16] and Frey et al. [13], [20]. All pterosaurs from the Solnhofen Limestone with a soft tissue cone-like head crest can be referred to Aerodactylus gen. nov. The preserved integument of BSP 1937 I 18 demonstrates a gular pouch, propatagium, tenopatagium, brachiopatagium and uropatagium. The gular pouch extends from the mandible, directly below the descending process of the nasal, to the caudal end of the fourth cervical vertebra. Close to the cranial end of the sixth cervical vertebra the integument sweeps towards the shoulders and continues to the pteroid to form the propatagium. The wing membrane is broad close to the body, but is narrow along the spar of the wing finger. The uropatagium is attached approximately a third of the way up the tibia, proximal to the ankle, and broadly sweeps to the hip, resulting in two independent membranes [15], [17], [51]. There is also evidence for pycnofibres on the neck of Aerodactylus gen. nov.[20], as in Gladocephaloideus [45].

Conclusions The taxonomy of Pterodactylus is complex due to a suite of plesiomorphic characters that are retained in early ontogeny. Recently, Bennett [2] referred “Pterodactylus longicollum” to the new genus; Ardeadactylus, and synonymised P. kochi with the type and (in our opinion) only species P. antiquus. This synonymy is likely to be erroneous considering that the focussed statistical analyses and a cladistics analysis presented here have demonstrated that “P. kochi” includes at least one other taxon. One such taxon within ‘P. kochi’ is “Pterodactylus scolopaciceps” Meyer 1860 [8]. “Pterodactylus scolopaciceps” is demonstrated to differ from Pterodactylus antiquus in the morphology of its skull and pteroid. Our statistical analysis finds that the two differ in the proportions of the orbit, humerus and pes, and so Aerodactylus gen. nov. is erected for the reception of “P. scolopaciceps”. Remaining specimens of P. kochi are found to have only a few proportions in common with P. antiquus. Notably, the cervical vertebrae of P. kochi are much shorter (nearly half the length when scaled to the same breadth) than those of P. antiquus, and thus we reject Jouve’s [24] and Bennett’s [2] synonymy. Further examination of the remaining specimens contained within P. kochi is required but our analysis suggests that it is generically distinct, and thus validates Diopecephalus Seeley, 1871 [52] (Vidovic and Martill in prep.). Furthermore “Germanodactylus rhamphastinus” is distinct from G. cristatus and requires further taxonomic evaluation. It is probable that “G. rhamphastinus” also belongs in Diopecephalus, as it has a straight dorsal rostrum, teeth beneath the nasoantorbital fenestra and short cervical vertebrae (Vidovic and Martill in prep.).

Acknowledgments Oliver Rauhut, Marcus Moser (Munich), Lorna Steel (London), Paul Jeffrey, Eliza Howlett (Oxford), Loic Costeur, Christian Meyer (Basel), Rainer Brocke (Frankfurt) and Rainer Schoch (Stuttgart) are thanked for access to specimens in their care. We would also like to thank Bob Loveridge for allowing us access to a specimen in his collection. Bob Loveridge, John Vidovic, Emma Lawlor and Sven Tränkner are thanked for providing photographs. We especially thank Chris Bennett (Fort Hayes), David Hone (London), Dino Frey (Karlsruhe) for the useful comments made during the project, Michael O’Sullivan, Richard Hing and Nick Minter (Portsmouth) for making comments on the manuscript, and Luke Hauser and Nathan Barling (Portsmouth) for helping with the new genus name. DMM would like to thank Helmut Tischlinger for access to his personal library. Finally, we thank the Linnaean Society and the Systematics Association for a grant to support museum visits.

Author Contributions Conceived and designed the experiments: SUV. Performed the experiments: SUV. Analyzed the data: SUV DMM. Contributed reagents/materials/analysis tools: SUV. Contributed to the writing of the manuscript: SUV DMM.