Preliminary systematics and diversity patterns of cyclostome bryozoans from the Neogene of the Central American Isthmus

2001 ◽  
Vol 75 (3) ◽  
pp. 578-589 ◽  
Author(s):  
Paul D. Taylor
Keyword(s):  
Central American ◽  
Diversity Patterns ◽  
Number Of Species ◽  
Low Latitudes ◽  
Preliminary Study ◽  
The Caribbean ◽  
Central American Isthmus

Cyclostome bryozoans are present in 83 samples collected as part of the Panama Paleontology Project (PPP) and representing sediments deposited during the Miocene-Pleistocene in several basins on the Caribbean and Pacific sides of the Central American Isthmus. Preliminary study has resulted in the identification of 23 species. Most of these are left in open nomenclature and assigned questionably to genera, pending detailed study and comparison with cyclostomes previously described from this region and elsewhere. Maximum sample diversity is 13 species and median diversity two species. An equal number of species is present in the Caribbean and Pacific basins. The cumulative collection curve for the PPP cyclostome samples shows a flattening, implying that further sampling will not increase diversity substantially. About 11 percent of calcareous species in the PPP bryozoan fauna are cyclostomes, the remainder being cheilostomes. This relatively small value is consistent with anecdotal data for Recent bryozoans which suggest a decrease in the proportion of cyclostomes within bryozoan faunas from high to low latitudes. Species with erect colonies dominate among the cyclostomes, in contrast with the PPP cheilostomes in which encrusting species greatly outnumber erect species.

scholarly journals Graphic correlation of deep sea and shallow marine deposits from the Central American Isthmus region: implications for Late Neogene paleoclimatology

1992 ◽  
Vol 6 ◽  
pp. 88-88
Author(s):  
Harry J. Dowsett
Keyword(s):  
Costa Rica ◽  
High Resolution ◽  
Ocean Circulation ◽  
Deep Sea ◽  
Sea Surface ◽  
Central American ◽  
Major Barrier ◽  
Late Neogene ◽  
The Caribbean ◽  
Central American Isthmus

The stratigraphic record in Panama and Costa Rica preserves the biologic and climatic changes associated with the formation of a major barrier to marine migration and ocean circulation. Creating a high resolution temporal framework within which stratigraphic sections found on the Isthmus can be interpreted is fundamental to our understanding the history and importance of these units.The Isthmus contains rich marine macro- and microfaunas and floras on both the Pacific and Atlantic margins. Planktic foraminifers and calcareous nannofossils are common and often well preserved. Preliminary analysis of these fossils reveals a rich sedimentary record spanning the Late Miocene to Pleistocene. Multivariate statistical analyses of these assemblages provide environmental estimates. Unfortunately, traditional methods of biostratigraphy are limited in their ability to create a high resolution temporal framework for the region. For example, a majority of deposits analyzed can be placed in planktic foraminiferal zone N19 (early Pliocene). In order to answer paleobiologic and paleoclimatic questions one requires more precise correlations between sections and some indication of duration of sedimentation represented by various sections.In an attempt to overcome the shortcomings of traditional biostratigraphic methods, the Graphic Correlation method has been applied to selected sequences on the Central American Isthmus. Graphic correlation (GC) is a procedure by which two sequences can be compared and correlated using a wide variety of stratigraphic information simultaneously. A GC model of late Neogene planktic foraminifer, calcareous nannofossil, and paleomagnetic reversal events has been produced through compositing of more than 26 deep sea cores and ocean margin sequences. Following routine GC procedures the positions of all fossil first and last occurrences from a number of sections on the Caribbean and Pacific sides of the Central American Isthmus (Panama and Costa Rica) have been recorded. These sections have been correlated to the GC model and hence, to each other, providing a temporal framework for the Isthmus units.Selected sections were then correlated to other sequences such as near-by deep sea cores which have been analyzed for sea surface temperature and salinity to gain a better understanding of the overall paleoceanographic development of the region between 5 and 2 Ma. For example, correlation of units on the Caribbean side of the Isthmus with DSDP Site 502 indicates little to no change in sea surface temperatures during the entire time the Isthmus was reaching closure. Mid-to-high latitude sites exhibit amplification of warming with increasing latitude. The shoaling Isthmus, while having negligible effects on tropical marine temperatures, was responsible for increased meridional heat transport which resulted in a North Atlantic warming about 3 Ma. A general model for paleoceanographic changes during the time of closure will be discussed.

scholarly journals Sedimentary dynamics and structural control of Neogene tropical biofacies during the formation of the Central American Isthmus

1992 ◽  
Vol 6 ◽  
pp. 62-62 ◽  
Author(s):  
Anthony Coates ◽  
Jorge Obando ◽  
Herman Gonzalez
Keyword(s):  
Structural Control ◽  
Sedimentary Basins ◽  
Conclusive Evidence ◽  
Central American ◽  
The Pacific ◽  
Pacific Side ◽  
Late Neogene ◽  
The Caribbean ◽  
Final Closure ◽  
Central American Isthmus

The central evolutionary, ecological and paleoceanographic questions of the American tropical Neogene relate to how and during what time the Central American Isthmus formed. Geographically, closure was located between the southern edge of the Chortis Block in southern Nicaragua and the Atrato Valley in Colombia. In this region we describe, on the Caribbean side, five Neogene sedimentary basins. They are the Atrato, Chucunaque, Gatun, Bocas del Toro, and Limon Basins. On the Pacific side the Neogene sediments formed as part of the Central American Trench and are well exposed in a series of uplifted blocks on the Nicoya, Osa and Burica Peninsulas. Our analysis allows 1) a construction of the sequence of contrasting sedimentary environments which characterize the different basins, giving a composite geological history of the isthmus for the Late Neogene and 2) identifies the comparable biofacies from the different basins which allow and constrain the evolutionary and ecological questions to be posed concerning the effect of the isthmus as a biogeographic barrier. Temporally, from it's partial emergence in the Middle Miocene, the isthmus shallows by the Early Pliocene (3.5–3.4 Ma) to less than 50 m (Duque-Caro, 1990) when there is a marked differentiation of shelf marine macrobenthic species between the Caribbean and the Pacific. The evidence from reliably dated, large, diverse exchanges of North and South American vertebrates on land constrains the final closure date to not later than 2.8–2.5 Ma (Marshall, 1988). Given that no conclusive evidence for final closure can come exclusively from a study of sedimentary facies, when depths of less than 50 m are involved, the present window of almost 1 Ma, during which final closure must have occurred, will only be narrowed further by the detailed study of very shallow-water fossil clades and complementary molecular data. Present studies indicate that such clades are abundantly preserved.

Neogene paleoenvironments of the Bocas del Toro Basin, Panama

1993 ◽  
Vol 67 (5) ◽  
pp. 699-710 ◽  
Author(s):  
Laurel S. Collins
Keyword(s):  
Central American ◽  
Caribbean Region ◽  
Bocas Del Toro ◽  
Late Pliocene ◽  
East Pacific ◽  
Foraminiferal Species ◽  
Southern Central ◽  
The Caribbean ◽  
Middle Pliocene ◽  
Central American Isthmus

Outcrops of upper Miocene to upper Pliocene sediments in the Bocas del Toro Basin, Caribbean coast of western Panama, contain a record of the emergence of the southern Central American isthmus. Paleodepths and characteristics of past sedimentary regimes within the basin were determined from benthic foraminiferal species assemblages. The present Valiente Peninsula shallowed from upper bathyal depths of about 300–500 m to outer neritic depths of 150–200 m between latest Miocene (5.6–6.5 Ma) and middle Pliocene (3.5–3.6 Ma) times. Outer neritic assemblages from about 100–150 m paleodepth on the island of Escudo de Veraguas indicate negligible emergence through the late Pliocene, and their present sea-level altitude suggests rapid Quaternary shallowing. Middle neritic foraminiferal assemblages of Cayo Agua island shallowed from depths of about 40–80 m to 20–40 m between early (4.5–5.0 Ma) and middle (3.5–3.6 Ma) Pliocene times. Cayo Agua assemblages indicate establishment of a carbonate regime in the southwestern Caribbean region prior to complete closure of the Caribbean–East Pacific seaway around 3.5 Ma.

The Belize Triangle: Relations with Britain, Guatemala and the United States

1990 ◽  
Vol 32 (1) ◽  
pp. 119-136 ◽  
Author(s):  
Anthony J. Payne
Keyword(s):  
United States ◽  
Central America ◽  
The United States ◽  
The Other ◽  
Central American ◽  
Democratic Change ◽  
Electoral Defeat ◽  
British Colonial ◽  
The Caribbean ◽  
Central American Isthmus

Within the international politics of the Caribbean Basin attention is only rarely paid to the position of Belize. This neglect is the more remarkable since Belize epitomizes — more precisely than any other territory of the region — the characteristic geopolitical problem of the Caribbean caught, as it were, uneasily between the United States, Latin America and Europe. Yet, despite being threatened by the Guatemalan claim to sovereignty over its territory, which delayed its independence until 1981, Belize has skillfully taken advantage of its British colonial past to carve out for itself a distinctive geopolitical space in Central America and the Caribbean. This has allowed it not only to remain relatively undisturbed by the conflicts which have riven the other states of the Central American isthmus, but also to display a commitment to democratic change strong enough to sustain the electoral defeat — in December 1984 — of a regime which had held power in the country for more than thirty years, as well as the defeat of its successor — in September 1989 — after just one term in office.

Tracer hydrology of the data-scarce and heterogeneous Central American Isthmus

2019 ◽  
Author(s):  
Ricardo Sánchez-Murillo
Keyword(s):  
Surface Water ◽  
Groundwater Recharge ◽  
Groundwater Resources ◽  
Central American ◽  
Seasonal Rainfall ◽  
Mountain Range ◽  
Summer Drought ◽  
Near Surface ◽  
The Caribbean ◽  
Central American Isthmus

Numerous socio-economic activities depend on the seasonal rainfall and groundwater recharge cycle across the Central American Isthmus. Population growth and unregulated land use changes resulted in extensive surface water pollution and a large dependency on groundwater resources. This chapter uses stable isotope variations in rainfall, surface water, and groundwater of Costa Rica, Nicaragua, El Salvador, and Honduras to develop a regionalized rainfall isoscape, isotopic lapse rates, spatial-temporal isotopic variations, and air mass back trajectories determining potential mean recharge elevations, moisture circulation patterns, and surface water-groundwater interactions. Intra-seasonal rainfall modes resulted in two isotopically depleted incursions (W-shaped isotopic pattern) during the wet season and two enriched pulses during the Mid-Summer Drought and the months of the strongest trade winds. Notable isotopic sub-cloud fractionation and near-surface secondary evaporation were identified as common denominators within the Central American Dry Corridor. Groundwater and surface water isotope ratios depicted the strong orographic separation into the Caribbean and Pacific domains, mainly induced by the governing moisture transport from the Caribbean Sea, complex rainfall producing systems across the N-S mountain range, and the subsequent mixing with local evapotranspiration, and, to a lesser degree, the eastern Pacific Ocean fluxes. Groundwater recharge was characterized by a) depleted recharge in highland areas (72.3%), b) rapid recharge via preferential flow paths (13.1%), and enriched recharge due to near-surface secondary fractionation (14.6%). Median recharge elevation ranged from 1,104 to 1,979 m a.s.l. These results are intended to enhance forest conservation practices, inform water protection regulations, and facilitate water security and sustainability planning in the Central American Isthmus.

Occurrence and biogeographic significance of Heliaster (Echinodermata: Asteroidea) from the Pliocene of southwest Florida

1988 ◽  
Vol 62 (01) ◽  
pp. 126-132 ◽  
Author(s):  
Douglas S. Jones ◽  
Roger W. Portell
Keyword(s):  
Central American ◽  
Eastern Pacific ◽  
Whole Body ◽  
Marine Fauna ◽  
Western Atlantic ◽  
Southwest Florida ◽  
Extant Species ◽  
Geologic Record ◽  
Central American Isthmus

Whole body asteroid fossils are rare in the geologic record and previously unreported from the Cenozoic of Florida. However, specimens of the extant species,Heliaster microbrachiusXantus, were recently discovered in upper Pliocene deposits. This marks the first reported fossil occurrence of the monogeneric Heliasteridae, a group today confined to the eastern Pacific. This discovery provides further non-molluscan evidence of the close similarities between the Neogene marine fauna of Florida and the modern fauna of the eastern Pacific. The extinction of the heliasters in the western Atlantic is consistent with the pattern of many other marine groups in the region which suffered impoverishment following uplift of the Central American isthmus.

Cryptotermes camelus (Isoptera: Kalotermitidae), a new drywood termite species from the Bolivian Chaco

Zootaxa ◽  
2021 ◽  
Vol 4938 (1) ◽  
pp. 145-147
Author(s):  
RUDOLF H. SCHEFFRAHN
Keyword(s):  
Exotic Species ◽  
New World ◽  
Caribbean Basin ◽  
Termite Species ◽  
The Third ◽  
Number Of Species ◽  
Asian Species ◽  
The Caribbean

Cryptotermes Banks, 1906 is the third most diverse kalotermitid genus worldwide after Glyptotermes Froggatt, 1897 and Neotermes Holmgren, 1911, with its greatest diversity found in the Neotropics (Krishna et al. 2013a). Furthermore, the greatest number of species of Cryptotermes are known from the Caribbean Basin (Scheffrahn & Křeček 1999, Casala et al. 2016, Scheffrahn 2019). Although Araujo (1977) and Bacchus (1987) list Cryptotermes domesticus (Haviland, 1898) from Trinidad (treated as mainland) and Panama, respectively, Scheffrahn & Křeček (1999) and Scheffrahn et al. (2009) doubt the existence of this Asian species in the New World. Without C. domesticus, the total extant Neotropical diversity of Cryptotermes is 29 endemic and three exotic species (Constantino 2020). 

Identification of Tropical Cyclones’ Critical Positions Associated with Extreme Precipitation Events in Central America

2021 ◽  
Author(s):  
Hugo G. Hidalgo ◽  
Eric J. Alfaro ◽  
Franklin Hernández-Castro ◽  
Paula M. Pérez-Briceño
Keyword(s):  
Central America ◽  
Tropical Cyclones ◽  
Critical Path ◽  
Central American ◽  
Pacific Basin ◽  
Extreme Precipitation Events ◽  
The Pacific ◽  
The Caribbean ◽  
Indirect Impacts ◽  
Precipitation Events

<p>Tropical cyclones are one of the most important causes of disasters in Central America. Using historical (1970–2010) tracks of cyclones in the Caribbean and Pacific basin, we identify critical path locations where these low-pressure systems cause the highest number of floods in a set of 88 precipitation stations in the region. Results show that tropical cyclones from the Caribbean and Pacific basin produce a large number of indirect impacts on the Pacific slope of the Central American isthmus. Although the direct impact of a tropical cyclone usually results in devastation in the affected region, the indirect effects are more common and sometimes equally severe. In fact, the storm does not need to be an intense hurricane to cause considerable impacts and damage. The location of even a lower intensity storm in critical positions of the oceanic basin can result in destructive indirect impacts in Central America. The identification of critical positions can be used for emergency agencies in the region to issue alerts of possible flooding and catastrophic events.</p>

A Different Perspective for the Financial Crisis in Latin America and the Caribbean

1985 ◽  
Vol 27 (4) ◽  
pp. 9-20 ◽  
Author(s):  
João Clemente Baena Soares
Keyword(s):  
Financial Crisis ◽  
Latin American ◽  
External Debt ◽  
Central American ◽  
South American ◽  
External Financing ◽  
Entire Region ◽  
Goods And Services ◽  
The Caribbean ◽  
Interest Payments

The Latin American and Caribbean countries are facing a serious financial crisis. External debt in the region is over $360 billion, and seven South American countries are among the ten largest debtors in the world. Interest payments alone required, in the years of 1982, 1983, and 1984, more than 35% of total regional exports of goods and services, a percentage which reached the extreme level of over 50% for one country. To be sure, this problem mostly affects the largest economies, since most of the Central American and Caribbean countries apply to interest payments less than 20% of their exports. The debt problem is a reality for the entire region, and it makes it difficult for all the countries to obtain new external financing.

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