Anais da Academia Brasileira de Ciências ISSN: 0001-3765 [email protected] Academia Brasileira de Ciências Brasil JACOBS, LOUIS L.; STRGANAC, CHRISTOPHER; SCOTESE, CHRISTOPHER Plate motions, Gondwana Dinosaurs, Noah's Arks, Beached Viking Funeral Ships, Ghost Ships, and Landspans Anais da Academia Brasileira de Ciências, vol. 83, núm. 1, marzo, 2011, pp. 3-22 Academia Brasileira de Ciências Rio de Janeiro, Brasil Available in: http://www.redalyc.org/articulo.oa?id=32717681002 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative “main” — 2011/2/10 — 12:16 — page 3 — #1 Anais da Academia Brasileira de Ciências (2011) 83(1): 3-22 (Annals of the Brazilian Academy of Sciences) Printed version ISSN 0001-3765 / Online version ISSN 1678-2690 www.scielo.br/aabc Plate Motions, Gondwana Dinosaurs, Noah’s Arks, Beached Viking Funeral Ships, Ghost Ships, and Landspans LOUIS L. JACOBS1, CHRISTOPHER STRGANAC1 and CHRISTOPHER SCOTESE2 1Roy M Huffington Department of Earth Sciences, Southern Methodist University, Dallas, TX, 75275, USA 2Department of Geology, University of Texas at Arlington, Arlington, TX, 76019, USA Manuscript received on November 10, 2009; accepted for publication on August 16, 2010 ABSTRACT Gondwana landmasses have served as large-scale biogeographic Noah’s Arks and Beached Viking Funeral Ships, as defined by McKenna. The latitudinal trajectories of selected Gondwana dinosaur localities were traced throughtime in order to evaluate their movement through climate zones relative to those in which they originally formed. The dispersal of fauna during the breakup of Gondwana may have been facilitated by the presence of offshelf islands forming landspans (sensu Iturralde-Vinent and MacPhee) in the Equatorial Atlantic Gateway and elsewhere. Key words: biogeography, dinosaur, Gondwana, latitude. INTRODUCTION Ark as a segment of continental crust with its biota, In 1973 Malcolm C. McKenna published a paper rifted and moved away from its continent of origin. He titled, “Sweepstakes, Filters, Corridors, Noah’s Arks, viewed Noah’s Arks as permitting one-way dispersal of and Beached Viking Funeral Ships in Palaeogeography”. a balanced biota during which “the transported biota His purpose was to reconcile the biogeographic princi- would evolve, and latitudinal components of motion ples elaborated by William Diller Matthew (e.g. Mat- would conceivably affect available ecospace via the ef- thew 1915, 1939) and George Gaylord Simpson (e.g. fects of climatic change” (McKenna 1973, p. 302). In Simpson 1940, 1943, 1946, 1947a, b, 1952, 1953), devel- the same paper, McKenna also defined biogeographic oped under a stable Earth perspective, with the then well Viking Funeral Ships as continental crust rifted away accepted framework of plate tectonics. His fundamen- from one landmass and travelled to an adjacent landmass, tal conclusion was that the dispersalist principles elabo- carrying fossils from the first area, where the popula- rated by Matthew and Simpson were still relevant with- tions had lived, to the second area where a Funeral Ship in certain mobilist caveats: sweepstakes routes are those beached and where the fossil biota had never lived. The in which odds of dispersal success are low, as in true formation of Noah’s Arks and Viking Funeral Ships are rafting; filters are those which allowed the dispersal of features of divergent plate boundaries. Docked Noah’s some but not other species, usually due to the adapta- Arks and Beached Viking Funeral Ships are features tions of the species involved and the environmental con- of convergent plate boundaries and accreted terranes. ditions of the route; and corridors are those in which Their effects on historical biogeography occur on the movement was the most free of all. spatial and temporal scales at which lithospheric plates McKenna (1973) defined a biogeographic Noah’s are created, subsumed, and move about. McKenna (1983) added more mobilist biogeo- Proceedings of the Third Gondwanan Dinosaur Symposium graphic concepts derived from his plate tectonics per- Correspondence to: Louis L. Jacobs E-mail: [email protected] spective. One was “Escalator Counterflow”, which en- An Acad Bras Cienc (2011) 83 (1) “main” — 2011/2/10 — 12:16 — page 4 — #2 4 LOUIS L. JACOBS, CHRISTOPHER STRGANAC and CHRISTOPHER SCOTESE visioned a rejuvenating volcanic pile at a spreading ever, if the concept of landspans is expanded to allow center without appreciable geographic displacement of subaerial connection punctuated by short water gaps be- the islands created, in which terrestrial organisms essen- tween off-shelf islands (i.e., those developed on oceanic tially moved “up the down escalator” through geologic crust) and two adjacent continents, then the concept of time. Another was “Hopscotch on the Escalator” result- landspans becomes relevant when considering the dis- ing from colonization of progressively younger islands persal of Gondwana dinosaurs, and elaborates the mo- along a hotspot trace, as exemplified by the Hawaiian bilist concepts presaged by McKenna. Islands and Emperor Seamounts. The older islands We have two purposes in this paper. The first is to move with the plate away from the hotspot, erode, and trace the latitudinal drift of selected Gondwana dinosaur subside below sea level. The biota skips from the older localities (Fig. 1, Table I) through time from the Trias- eroding and subsiding island to newly formed islands sic (220 Ma, Carnian), when continents were united in at the intraplate hotspot. Some of the plants of Iceland, Pangea, until the present day. This is useful for compar- which have a fossil record going back to the Miocene ing where fossil localities were formed to where they origin of the islands (Grímsson et al. 2007), provide a are now in terms of the climate zones they traversed possible example of Escalator Counterflow. The Gala- because, to repeat again McKenna’s words, “latitudinal pagos biota (Christie et al. 1992, Grehan 2001) is possi- components of motion would conceivably affect avail- bly an example of Hopskotch on the Escalator. Another able ecospace via the effects of climatic change”. Gen- example might be living coelacanths on the slopes of eral Circulation Models (GCMs) consistently indicate underwater volcanoes near the Comoro Islands (Fricke high global temperatures and low latitudinal tempera- and Hissman 1990). The volcanos formed much later ture gradients during the Mesozoic (Sellwood and Valdes than the clade. Green sea turtles that breed on islands of 2006). Nevertheless, GCMs are tested by the rock and the Mid-Atlantic Ridge (Carr and Coleman 1974, Bowen fossil records, so unless otherwise determined, the first et al. 1989) may also represent hopscotch. However, order causes of climate zonation should have been ap- neither concept has seen much application to non-avian plicable in the Mesozoic as they are now, modified by dinosaurs. higher order climatic influences included in the models. More recently, historical biogeography of islands Non-avian dinosaur localities, Gondwana dinosaur was revitalized with the introduction of landspans, de- localities in particular, are ideal for this sort of review fined by Iturralde-Vinent and MacPhee (1999, p. 52)as because they reflect the breakup of Gondwana into its “a subaerial connection (whether continuous or punctu- constituent components and their dispersal to their pres- ated by short water gaps) between a continent and an ent positions on the globe. The breakup of Gondwana off-shelf island (or island arc)”. This stands opposed brought about first-order biogeographic change for all to land bridges, which Iturralde-Vinent and Macphee its component terrestrial biota. Africa, South America, (1999, p. 52) restricted to mean “land linkages between Madagascar, India, Australia, and Antarctica were, in continental regions”. A significant difference between effect, very large-scale Noah’s Arks. The tectonic drift the two is the dispersal of organisms between lands on of these arks through latitudinal climate zones was the oceanic and continental crust in the former, and lands on first-order cause of environmental changes to which the continental crust only in the latter. Iturralde-Vinent and biota living on the drifting Gondwana fragments was MacPhee (1999) applied the concept of the GAARlan- subjected. Each fragment of Gondwana moved through dia landspan, which is defined as a landmass comprising climatic zones at different rates and crossed climatic the conjoined Greater Antilles and Aves Ridge islands, boundaries at times specific to the place. and then examined dispersal mechanisms in the light Our second, more speculative purpose is to iden- of sea-level change, tectonic evolution, and vicariance tify where and when landspans may have most greatly of the Carribean fauna (Iturralde-Vinent and MacPhee affected Gondwana dinosaur dispersal in the context 1999). The purpose of Iturralde-Vinent and MacPhee of continental movements. The relationships of land- (1999) was to explain the biota of the Antilles; how- masses in close proximity to each other as they converge An Acad Bras Cienc (2011) 83 (1) “main” — 2011/2/10 — 12:16 — page 5 — #3 GONDWANA LATITUDINAL BIOGEOGRAPHY 5 or diverge in tectonically active terranes deserve atten- 2003), from modeling (Sellwood and Valdes 2006, Hay-