54 research outputs found

    Pterodactylus scolopaciceps Meyer, 1860 (Pterosauria, Pterodactyloidea) from the Upper Jurassic of Bavaria, Germany:the problem of Cryptic Pterosaur Taxa in early ontogeny

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    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

    The oldest Jurassic dinosaur:a Basal Neotheropod from the Hettangian of Great Britain

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    Approximately 40% of a skeleton including cranial and postcranial remains representing a new genus and species of basal neotheropod dinosaur is described. It was collected from fallen blocks from a sea cliff that exposes Late Triassic and Early Jurassic marine and quasi marine strata on the south Wales coast near the city of Cardiff. Matrix comparisons indicate that the specimen is from the lithological Jurassic part of the sequence, below the first occurrence of the index ammonite Psiloceras planorbis and above the last occurrence of the Rhaetian conodont Chirodella verecunda. Associated fauna of echinoderms and bivalves indicate that the specimen had drifted out to sea, presumably from the nearby Welsh Massif and associated islands (St David's Archipelago). Its occurrence close to the base of the Blue Lias Formation (Lower Jurassic, Hettangian) makes it the oldest known Jurassic dinosaur and it represents the first dinosaur skeleton from the Jurassic of Wales. A cladistic analysis indicates basal neotheropodan affinities, but the specimen retains plesiomorphic characters which it shares with Tawa and Daemonosaurus

    Vision, challenges and opportunities for a Plant Cell Atlas

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    With growing populations and pressing environmental problems, future economies will be increasingly plant-based. Now is the time to reimagine plant science as a critical component of fundamental science, agriculture, environmental stewardship, energy, technology and healthcare. This effort requires a conceptual and technological framework to identify and map all cell types, and to comprehensively annotate the localization and organization of molecules at cellular and tissue levels. This framework, called the Plant Cell Atlas (PCA), will be critical for understanding and engineering plant development, physiology and environmental responses. A workshop was convened to discuss the purpose and utility of such an initiative, resulting in a roadmap that acknowledges the current knowledge gaps and technical challenges, and underscores how the PCA initiative can help to overcome them.</jats:p

    Is open access tarnished?

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    As open access terms have split into colour-coded brands, not all allow totally unrestricted access and reuse. Among these, “bronze OA” stands out as a potentially damaging misnomer, writes Steven Vidovi

    The origins of major sessile cirripede groups; a revision of Cretaceous Brachylepadomorpha and Verrucomorpha

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    The taxonomy of Cretaceous cirripedes referred to the sessile orders Brachylepadomorpha and Verrucomorpha is revised. New taxa include the brachylepadid genera Crithmumlepas (type species C. hoensis sp. nov., C. aycliffensis sp. nov.) and Calvatilepas (type species C. recurvus sp. nov.). The family Pycnolepadidae nov. is established (constituent genera Pycnolepas, Faxelepas) and Pycnolepas batchelorum sp. nov. is described; a new eoverrucid species, E. barringtonensis sp. nov. is erected. Cladistic analysis of 48 characters of 18 operational taxonomic units, including 16 in-group sessile taxa yielded a consensus tree showing the strongly supported monophyly of Brachylepadomorpha + Verrucomorpha + Balanomorpha. It is recommended that the Order Brachylepadomorpha is abandoned, and its constituent families are identified as, respectively, stem group Verrucomorpha (Pycnolepadidae) and stem group Balanomorpha (Brachylepadidae). The sister-group relationship of Verrucomorpha and Balanomorpha, identified from many molecular studies, is confirmed from shell morphological data. The Neolepadoidea are shown to closely parallel the sessile adaptations of verrucomorphs and balanomorphs. The fossil record of key segments of cirripede evolution is demonstrated to be remarkably, and surprisingly, complete

    The taxonomy and phylogeny of <i>Diopecephalus kochi</i> (Wagner, 1837) and “<i>Germanodactylus rhamphastinus</i>” (Wagner, 1851): Taxonomy of <i>Diopecephalus</i> and <i>Germanodactylus</i>

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    The Solnhofen pterosaurs Pterodactylus antiquus, Aerodactylusscolopaciceps, 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

    A private specimen of <i>Aerodactylus</i> demonstrating the shoulder girdle morphology.

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    <p>A) A photograph of a private specimen, which plots onto all graphs on the regression line belonging to morphotype two, thus is identified as <i>Aerodactylus scolopaciceps</i> gen. nov. The area of the photograph illustrates the morphology of the coracoid and humerus. The humerus is more similar to that of <i>Aurorazhdarcho</i>, but the proportions of the wing metacarpal are similar to <i>Aerodactylus scolopaciceps</i> 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.</p

    Skull length <i>vs</i> skull depth.

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    <p>A graph demonstrating the spread of data between morphotype one (open circles), morphotype two (filled circles) and <i>Pterodactylus antiquus</i> (Open square) in respect to their skull length and skull depth. Solid black lines = regression lines for respective morphotypes; dashed grey lines = 95% confidence limits.</p
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