Browsing by Author "Iturralde-Vinent, Manuel."
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Item Domo de Zaza, an early Miocene vertebrate locality in south-central Cuba : with notes on the tectonic evolution of Puerto Rico and the Mona Passage. American Museum novitates ; no.3394(New York, NY : American Museum of Natural History, 2003) MacPhee, R. D. E.; Iturralde-Vinent, Manuel.; Gaffney, Eugene S.This report summarizes the results of paleontological and geological investigations carried out during the 1990s at Domo de Zaza, a late early Miocene vertebrate locality in south-central Cuba. Paleontologically, the most important result of fieldwork at Zaza was the first discovery of terrestrial mammals of Tertiary age in Cuba. Three terrestrial mammal taxa are now known from this locality--a megalonychid sloth (Imagocnus zazae), an isolobodontine capromyid rodent (Zazamys veronicae), and a platyrrhine primate (Paralouatta marianae, new species). In addition to these finds, a number of selachian, chelonian, crocodylian, cetacean, and sirenian remains have been recovered. Domo de Zaza is a low hill transected by a large artificial channel, the Canal de Zaza, whose walls provide an extensive exposure of Miocene sediments attributable to the Lagunitas Formation (Fm). This formation is laterally and vertically complex, showing evidence of at least four different depositional regimes. However, the sedimentary sequence indicates that all depositional phases took place within a broader episode of transgression. Estimated Burdigalian age (16.1-21.5 Ma) for Lagunitas Fm is based on the presence of marine invertebrate taxa corresponding to the late early Miocene Miogypsina-Soritiidae zone. The overall transgressive aspect of Lagunitas suggests rising sea level, possibly in correlation with a global onlap event. Within Burdigalian time, the most likely correlate is the eustatic rise centered on 17.5-18.5 Ma. Most of the vertebrate fossils were recovered from lagoonal and alluvial beds; those from lagoonal beds are exceptionally well preserved. The terrestrial facies displays evidence of paleosol formation, subaerial erosion, and plant life in the form of grass and palm pollen. Other evidence indicates that most of the present-day highlands of Cuba, including the Cordillera del Escambray near Zaza, have been continuously subaerial since the latter part of the late Eocene. Although no land vertebrate fossils of this age are known from Cuba, recent discoveries elsewhere in the Greater Antilles indicate that land vertebrates could have colonized landmasses in the Caribbean Basin as early as 33-36 Ma. Recently, marine geological data have been interpreted as showing that (1) the Mona Passage began to form in the early Oligocene, and (2) the Puerto Rico/Virgin Island block was entirely transgressed by shallow marine environments during the period between the late Oligocene and the early Pliocene. However, the seismic reflection profile evidence for an early Oligocene opening of the passage is ambiguous. Even if the separation of Puerto Rico and eastern Hispaniola occurred relatively early, it remains more probable than not that this happened in the medial Oligocene or even somewhat later (i.e., ≤30 Ma). On the other hand, the evidence is not at all ambiguous concerning the hypothesized mid-Cenozoic inundation of Puerto Rico: it did not happen. When available land and marine indicators are adequately compared, apparent contradictions in datasets can be evaluated and resolved. When examined in this way, the preponderance of evidence supports the contention that Puerto Rico has been an emergent landmass and has supported terrestrial environments continuously since the latest Eocene.Item First Tertiary land mammal from Greater Antilles : an early Miocene sloth (Xenarthra, Megalonychidae) from Cuba. American Museum novitates ; no. 3094(New York, N.Y. : American Museum of Natural History, 1994) MacPhee, R. D. E.; Iturralde-Vinent, Manuel.Item Origin of the Greater Antillean land mammal fauna. 1, New Tertiary fossils from Cuba and Puerto Rico. American Museum novitates ; no. 3141(New York, N.Y. : American Museum of Natural History, 1995) MacPhee, R. D. E.; Iturralde-Vinent, Manuel.Item Paleogeography of the Caribbean region : implications for Cenozoic biogeography. Bulletin of the AMNH : no. 238([New York] : American Museum of Natural History, 1999) Iturralde-Vinent, Manuel.; MacPhee, R. D. E."This paper presents a series of detailed paleogeographical analyses of the Caribbean region, beginning with the opening of the Caribbean basin in the Middle Jurassic and running to the end of the Middle Miocene. Three intervals within the Cenozoic are given special treatment: Eocene-Oligocene transition (35-33 Ma), Late Oligocene (27-25 Ma), and early Middle Miocene (16-14 Ma). While land mammals and other terrestrial vertebrates may have occupied landmasses in the Caribbean basin at any time, according to the interpretation presented here the existing Greater Antillean islands, as islands, are no older than Middle Eocene. Earlier islands must have existed, but it is not likely that they remained as such (i.e., as subaerial entities) due to repeated transgressions, subsidence, and (not incidentally) the K/T bolide impact and associated mega-tsunamis. Accordingly, we infer that the on-island lineages forming the existing (i.e., Quaternary) Antillean fauna must all be younger than Middle Eocene. The fossil record, although still very poor, is consistent with the observation that most land mammals lineages entered the Greater Antilles around the Eocene-Oligocene transition. Western Laurasia (North America) and western Gondwana (South America) were physically connected as continental areas until the mid-Jurassic, ca. 170 Ma. Terrestrial connections between these continental areas since then can only have occurred via landbridges. In the Cretaceous, three major uplift events, recorded as regional unconformities, may have produced intercontinental landbridges involving the Cretaceous Antillean island arc. The Late Campanian/Early Maastrichtian uplift event is the one most likely to have resulted in a landbridge, as it would have been coeval with uplift of the dying Cretaceous arc. However, evidence is too limited for any certainty on this point. The existing landbridge (Panamanian Isthmus) was completed in the Pliocene; evidence for a precursor bridge late in the Middle Miocene is ambiguous. We marshal extensive geological evidence to show that, during the Eocene-Oligocene transition, the developing northern Greater Antilles and northwestern South America were briefly connected by a "landspan" (i.e., a subaerial connection between a continent and one or more offshelf islands) centered on the emergent Aves Ridge. This structure (Greater Antilles + Aves Ridge) is dubbed GAARlandia. The massive uplift event that apparently permitted these connections was spent by 32 Ma; a general subsidence followed, ending the GAARlandia landspan phase. Thereafter, Caribbean neotectonism resulted in the subdivision of existing land areas. The GAARlandia hypothesis has great significance for understanding the history of the Antillean biota. Typically, the historical biogeography of the Greater Antilles is discussed in terms of whether the fauna was largely shaped by strict dispersal or strict continent-island vicariance. The GAARlandia hypothesis involves elements of both. Continent-island vicariance sensu Rosen appears to be excludable for any time period since the mid-Jurassic. Even if vicariance occurred at that time, its relevance for understanding the origin of the modern Antillean biota is minimal. Hedges and co-workers have strongly espoused over-water dispersal as the major and perhaps only method of vertebrate faunal formation in the Caribbean region. However, surface-current dispersal of propagules is inadequate as an explanation of observed distribution patterns of terrestrial faunas in the Greater Antilles. Even though there is a general tendency for Caribbean surface currents to flow northward with respect to the South American coastline, experimental evidence indicates that the final depositional sites of passively floating objects is highly unpredictable. Crucially, prior to the Pliocene, regional paleoceanography was such that current-flow patterns from major rivers would have delivered South American waifs to the Central American coast, not to the Greater or Lesser Antilles. Since at least three (capromyid rodents, pitheciine primates, and megalonychid sloths) and possibly four (nesophontid insectivores) lineages of Antillean mammals were already on one or more of the Greater Antilles by the Early Miocene, Hedges' inference as to the primacy of over-water dispersal appears to be at odds with the facts. By contrast, the landspan model is consistent with most aspects of Antillean land-mammal biogeography as currently known; whether it is consistent with the biogeography of other groups remains to be seen"--P. 3.Item Synopsis of Late Jurassic marine reptiles from Cuba. American Museum novitates ; no. 3164(New York, N.Y. : American Museum of Natural History, 1996) Iturralde-Vinent, Manuel.; Norell, Mark.