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Current Knowledge Concerning Distribution of Freshwater Planktonic, Littoral and Benthic Rotifera and Microcrustacea (Cladocera, Copepoda and Ostracoda) in Central America and the Caribbean. Free access until march 22 usign the following link: https://authors.elsevier.com/c/1gWF~HHE-jEhc
Abstract
Abstract
Central America and the Caribbean, at the northern limit of the Neotropical region, is made up of a narrow strip of land and numerous islands, with a complex geological history, represents an important biogeographic connection between North and South America and contains diverse freshwater environments, including high mountain and lowlands lakes and wetlands. We examined literature reports and databases for freshwater planktonic, benthic and littoral Rotifera and microcrustacea distribution in the area in order to update, unify and summarize disparate information that has accumulated since Collado et al.’s initial contribution in 1984 that listed 369 specific and infraspecific taxa. We used the most common databases and keywords to locate papers on Rotifera, Cladocera, Ostracoda and Copepoda and found 457 new records from more than 200 study sites that list 92 genera and 782 species, as well as over 30 infraspecific taxa, for the region. These included 84%, 53%, 37% and 21% respectively, of known neotropical species of these groups. Analysis using the Sorensen-Dice Similarity Index showed high heterogeneity in species composition for the area and hierarchical clustering suggests three groups for the Caribbean islands. Lack of resources has hindered the formal publication of research. We conclude that a collaborative effort is needed to produce scientists capable of combining taxonomic information with ecological studies to enhance understanding of anthropogenic impacts on water resources.
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2004) The natural diet of Apocyclops panamensis at a shrimp farm on the Pacific coast of Nicaragua. Zoological Studies 43(2): 344-349. Gut contents of 1150 adults of Apocyclops panamensis were examined to obtain information on its feeding habits in extensive shrimp ponds during a 16-week period (10 June ~ 5 Sept. 1999). Temporal changes in the relative abundance of ingested algae were studied and compared with the natural phytoplankton assemblage in the pond. The phytoplankton community was comprised of diatoms and blue-green and green algae; total abundance varied between 1.11 x 10 4 and 10.2 x 10 4 cells/ml, of which blue-green algae, such as Lyngbya limnetica, Spirulina nodosa, and Anabaenopsis sp., were the most abundant. During the study period, diatoms made up 89% of the algal cells consumed by A. panamensis. Among the diatoms, Nitzschia sp. was most important, while Navicula sp. and Amphora ovalis were also substantial. The green alga, Chlorella sp., accounted for 10.6%; blue-green algae were rarely consumed.
Geodiversity is recognized as one of the most important drivers of ecosystem characteristics and biodiversity globally. However, in the northern Neotropics, the contribution of highly diverse landscapes, environmental conditions, and geological history in structuring large-scale patterns of aquatic environments and aquatic species associations remains poorly understood. We evaluated the relationships among geodiversity, limnological conditions, and freshwater ostracodes from southern Mexico to Nicaragua. A cluster analysis (CA), based on geological, geochemical, mineralogical, and water-column physical and chemical characteristics of 76 aquatic ecosystems (karst, volcanic, tectonic) revealed two main limnological regions: (1) karst plateaus of the Yucatán Peninsula and northern Guatemala, and (2) volcanic terrains of the Guatemalan highlands, mid-elevation sites in El Salvador and Honduras, and the Nicaraguan lowlands. In addition, seven subregions were recognized, demonstrating a high heterogeneity of aquatic environments. Principal component analysis (PCA) identified water chemistry (ionic composition) and mineralogy as most influential for aquatic ecosystem classification. Multi-parametric analyses, based on biological data, revealed that ostracode species associations represent disjunct faunas. Five species associations, distributed according to limnological regions, were recognized. Structural equation modeling (SEM) revealed that geodiversity explains limnological patterns of the study area. Limnology further explained species composition, but not species richness. The influence of conductivity and elevation were individually evaluated in SEM and were statistically significant for ostracode species composition, though not for species richness. We conclude that geodiversity has a central influence on the limnological conditions of aquatic systems, which in turn influence ostracode species composition in lakes of the northern Neotropical region.
This paper presents a study of freshwater zooplankton biodiversity, deemed as a reliable indicator of water quality. The Guatemalan Lake Amatitlán, currently used as a water source, has shown signs of progressive eutrophication, with perceptible variations of the local zooplankton diversity. Biotic and abiotic parameters were determined at four sites of Lake Amatitlán (Este Centro, Oeste Centro, Bahía Playa de Oro, and Michatoya) in 2016 and 2017. The local composition, the species richness and abundance of zooplankton, and the system environmental parameters were analyzed during both years surveyed. Biological data suggesting eutrophication of this tropical system were obtained, including a high rotifer abundance (11 species: the rotifers Brachionushavanaensis (109 ind L−1) and Keratellaamericana (304 ind L−1) were the most abundant species in this lake). The presumably endemic diaptomid copepod species, Mastigodiaptomusamatitlanensis, was absent in our samples, but we report the unprecedented occurrence of two Asian cyclopoid copepods (i.e., Thermocyclopscrassus and Mesocyclops thermocyclopoides) for Lake Amatitlán and Guatemala. The presence of larger zooplankters like adults and immature copepods (i.e., Arctodiaptomusdorsalis) and cladocerans (Ceriodaphnia sp.) at site “Este Centro” indicates a relatively healthy zooplankton community and represents a focal point for managing the conservation of this lake.
The last 85,000 years were characterized by high climate and environmental variability on the Yucatán Peninsula. Heinrich stadials are examples of abrupt climate transitions that involved shifts in regional temperatures and moisture availability. Thus, they serve as natural experiments to evaluate the contrasting responses of aquatic and terrestrial ecosystems. We used ostracodes and pollen preserved in a 75.9-m-long sediment core (PI-6, ∼85 ka) recovered from Lake Petén Itzá, Guatemala, to assess the magnitude and velocity of community responses. Ostracodes are sensitive to changes in water temperature and conductivity. Vegetation responds to shifts in temperature and the ratio of evaporation to precipitation. Ostracodes display larger and more rapid community changes than does vegetation. Heinrich Stadial 5-1 (HS5-1) was cold and dry and is associated with lower ostracode and vegetation species richness and diversity. In contrast, the slightly warmer and dry conditions during HS6 and HS5a are reflected in higher ostracode species richness and diversity. Our paleoecological study revealed the greatest ecological turnover for ostracodes occurred from 62.5 to 51.0 ka; for pollen, it was at the Pleistocene/Holocene transition. Future studies should use various climate and environmental indicators from lake and marine sediment records to further explore late glacial paleoclimate causes and effects in the northern neotropics.
Detailed surveys on rarely examined aquatic ecosystems often lead to the discovery of new species of high conservation value. This study directed towards the recognition of a variety of aquatic environments in Costa Rica (40 habitats, including lakes, wetlands and small aquatic systems, e.g. ponds, ditches, puddles, tree holes and bromeliads) established the presence of 105 species of Monogononta representing 33 genera. In total, 91 species and 19 genera were found to be new for Costa Rica, including 29 species recorded for the first time in Central America (e.g. Ascomorpha klementi, Beauchampia crucigera, Brachionus mirabilis, Cephalodella panarista, Filinia saltator, Horaella brehmi, Lecane amazonica, Lecane pawlowskii, Lepadella lindaui and Mytilina acanthophora). The application of two estimates of total species richness allowed us predict that 70 new rotifer species may potentially be found in Costa Rica. Thus, we assume that only about 60% of the potential Costa Rican rotifer diversity was ascertained in our study. The most diverse genus was Lecane with 36 species. Among the most frequent rotifers there were some lecanid species, e.g. Lecane bulla, Lecane hamata, Lecane closterocerca and Lecane leontina, and also Colurella obtusa, Plationus patulus, Anuraeopsis fissa and Platyias quadricornis.
Long-term plankton studies in neotropical lakes are scarce. Here we studied plankton composition in Lake Cote, Costa Rica, twice per year from 2002 to 2018, to monitor changes after it was modified as a reservoir for hydroelectricity in 2003. Plankton variation was examined for a long-term trend and its relationship with basic limnological characteristics of the lake. Phytoplankton was sampled from the surface and with a depth-integrating sampler. Zooplankton was caught with vertical hauls, at the same station at the middle of the lake. A total of 138 taxa of microalgae occurred, most from Chlorophyta and Cyanobacteria, to which dominant species belonged; Aulacoseira granulata was also ubiquitous. A shift in dominance occurred, from Cosmarium asphaerosporum to Aphanothece cf. microscopica, and Aphanocapsa cf. delicatissima. Zooplankton included 23 species of Cladocera, Copepoda, Rotifera, and Chaoborus. Most abundant were Keratella americana, Eubosmina tubicen, and Cyclopoida; Daphnia laevis became abundant after 2007 while E. tubicen declined. There was little correspondence between both planktonic components. Plankton composition was typical of a mesotrophic to eutrophic shallow lake, but changes indicated an increase in stratification, and can be attributed to combined effects of recent warming and outflow management for hydropower production.
The launch of the Dutch Caribbean Species Register by Naturalis Biodiversity Center (2017)—https://www.dutchcaribbeanspecies.org/—raised the question of which branchiopods originate from this part of the Netherlands. To answer this question, surveys of literature and of the Naturalis collection were conducted. The additional samples (collected in 2003–2005 and 2008) were analyzed. We present an annotated checklist of the Branchiopoda of the Dutch Caribbean. The Kingdom of the Netherlands includes the Dutch mainland and six Caribbean islands. From the Caribbean part of the kingdom, an annotated list of all known species is given. Fifteen taxa and three genera have been encountered and the species are discussed. To date, six species of large branchiopods and nine species of cladocerans are known. Two more genera of cladocerans have been found. One species is endemic to Bonaire.
The male of Canthocamptus s.l. (Elaphoidella) striblingi, a new species of harpacticoid copepod from the Monteverde Cloud Forest Preserve, Costa Rica, is distinguished within its subgenus by the biarticular endopods of legs 1 and 4; the exopod of leg 5 and the endopod of leg 2 each having 4 setae; and the unmodified spines of the exopod of leg 4. The female is unknown.
We present an updated, subjective list of the extant, non-marine ostracod genera and species of the world, with their distributions in the major zoogeographical regions, as well as a list of the genera in their present hierarchical taxonomic positions. The list includes all taxa described and taxonomic alterations made up to 1 July 2018. Taxonomic changes include 17 new combinations, 5 new names, 1 emended specific name and 11 new synonymies (1 tribe, 4 genera, 6 species). Taking into account the recognized synonymies, there are presently 2330 subjective species of non-marine ostracods in 270 genera. The most diverse family in non-marine habitats is the Cyprididae, comprising 43.2% of all species, followed by the Candonidae (29.0%), Entocytheridae (9.1%) and the Limnocytheridae (7.0%). An additional 13 families comprise the remaining 11.8% of described species. The Palaearctic zoogeographical region has the greatest number of described species (799), followed by the Afrotropical region with 453 species and the Nearctic region with 439 species. The Australasian and Neotropical regions each have 328 and 333 recorded species, respectively, while the Oriental region has 271. The vast majority of non-marine ostracods (89.8%) are endemic to one zoogeographical region, while only six species are found in six or more regions. We also present an additional list with ‘uncertain species’, which have neither been redescribed nor re-assessed since 1912, and which are excluded from the main list; a list of taxonomic changes presented in the present paper; a table with the number of species and % per family; and a table with numbers of new species described in the 20-year period between 1998 and 2017 per zoogeographical region. Two figures visualize the total number of species and endemic species per zoogeographical region, and the numbers of new species descriptions per decade for all families and the three largest families since 1770, respectively.
Zooplankton in small tropical lakes has been little studied and its variation during the year may respond to different factors. In this study, the zooplankton of a small neotropical lake was studied at different times during one year and compared with changes in the lake conditions and in phytoplankton composition. The lake stratifies from March until September, and mixes during the hemispherical winter, from October until February. Besides the lake show a seasonal fluctuation in water level according to the seasonality of rains. Zooplankton was composed of at least 13 species, four Cladocerans, three Copepods, four Rotifers and other groups such as an Ostracod and the larvae of Chaoborus. The most abundant were Thermocyclops sp., Daphnia sp. and Keratella tropica. Their abundance fluctuated along the year, probably in response to changes in lake level and changes in hydrological conditions, increasing during dry season when the main outlet of the lake dried up. Changes in phytoplankton composition do not seem to be as relevant for zooplankton variation in this small lake. Rev. Biol. Trop. 66(Suppl. 1): S123-S131. Epub 2018 April 01.
Cerro Chato Lake was visited in April, May, and lune 1992. The lake is located within an intemlediate-�ti tude cratedn Costa Rica, Central America. It has steep sides and reaches a maximum depth of 18.8 m. The lake has no surface oullet, nevertheless, its water has a low concentration of solutes, possibly because of rain fal! and underground seepage. Water column stratification was observed in all visits with a cJinograde oxygen curve and anoxic conditions below 15 m. The Phytoplankton was composed mainly of small chlorophytes and other algae, with a total of 43 spe cies. The diversity was low due to strong dominance of Arthrodesmus bifidus, and the Zooplankton, dominated by Tro pocyclops prasinus prasinus, incJuded four species of Cladocera. Large filter feeders were not observed which may partially explain dominance of small algae.
Freshwater ostracodes from the Neotropical-Caribbean region are potentially excellent tools for evolutionary and paleoenvironmental studies but their use is limited, because integrated data in taxonomy, environmental, and geographical preferences of the species at large scale remain unknown. A total of 118 species were recorded in the Neotropical-Caribbean region based on existing literature and results from fieldwork. About 74% of the species are restricted to the region and most of them show limited distributional areas as a consequence of environmental heterogeneity. Based on Parsimony Analysis of Endemicity, five areas of endemism were identified: (1) southern Florida, (2) southern Mexico-northern Central America, (3) Cuba, (4) Lesser Antilles, and (5) northern Venezuela-Aruba-Curacao-Trinidad. The conservation status of these areas was revised and lake ecosystems with endemic taxa were proposed to be included in environmental protection initiatives. Biogeographical analysis showed a strong differentiation between the ostracode faunas of the Neotropical-Caribbean region and the Neotropical-Neogen region. Few exchanges of species were attributed to ecological and geographical barriers such as volcanism and irregular orography. Faunal affinities within the Neotropical-Caribbean region indicated closer relationship between southern Mexico, southern Florida and the Antilles suggesting a common biogeographical history. Middle Central America and Chiapas-Guatemala highlands were discriminated as isolated regions.
DNA barcoding, based on sequence diversity in the mitochondrial COI gene, has proven an excellent tool for identifying species in many animal groups. Here, we report the first barcode studies for freshwater zooplankton from Mexico and Guatemala and discuss the taxonomic and biological implications of this work. Our studies examined 61 species of Cla-docera and 21 of Copepoda, about 40% of the known fauna in this region. Sequence divergences among conspecific individuals of cladocerans and copepods averaged 0.82% and 0.79%, respectively, while sequence divergences among congeneric taxa were on average 15-20 times as high. Barcodes were successful in discriminating all species in our study, but sequences for Mexican Daphnia exilis overlapped with those of D. spinulata from Argentina. Our barcode data revealed evidence of many species overlooked by current classification systems -for example, based on COI genotypes the Diapahanosoma birgei group appears to include 5 species, while Ceriodaphnia cf. rigaudi, Moina cf. inicrura, Mastigodiaptomus albuquerquensis and Mastigodiaptomus reidae all include 2-3 taxa. The barcode results support recent taxonomic revisions, such as recognition of the genus Lebenis, and the presence of several species in the D. birgei and Chydorus sphaericus complexes. The present results indicate that DNA barcoding will provide powerful new insights into both the incidence of cryptic species and a better understanding of zooplankton distributions, aiding evaluation of the factors influencing competitive outcomes, and the colonization of aquatic environments.
Taxonomic analysis of the copepod specimens collected from 29 Cayman Island ponds revealed the presence of ten species including the nearly ubiquitous cyclopoid Apocyclopspanamensis. This species was widespread throughout the islands, being collected at 27 of the sampling sites. Another common calanoid, Mastigodiaptomus nesus, occurred at nine sites on Grand Cayman and one on Cayman Brac. A cyclopoid of Afro-Asian origin, Mesocyclops ogunnus, was collected at two nearly fresh water sites on Grand Cayman and was considered to be a recent introduction. Because of its known adaptability to fluctuating environmental conditions, it is likely that M. ogunnus will successfully compete with and probably displace some of the native species and may become a dominant zooplankter on Grand Cayman.
This article reviews modern statistical approaches to estimating species diversity and biotic similarity from empirical samples of species abundance or incidence. Key methods include rarefaction, extrapolation, and non-parametric estimation of the asymptote of species richness. Hill numbers are presented as unifying indices of species diversity that take into account the relative abundance of different species. Species richness estimators, Hill numbers, and measures of biotic similarity can be extended to account for phylogenetic, taxonomic, and functional diversity of biological assemblages. These statistical methods control for sampling effects in biodiversity data and can be applied to many important questions in ecology.
We analyzed modern ostracode species assemblages and water column physico-chemical characteristics in Lago Péten Itzá, Guatemala. Lake waters are dominated by sulfate, bicarbonate, calcium and magnesium and display a total ion concentration of ~11 meq L-1. Eleven extant ostracode species were identified. We found higher abundances of living ostracodes, as well as relatively higher species richness (eight species) and biodiversity (H of 1.6) between the littoral zone and a water depth of <20 m. At water depths >40 m, these variables all decreased. The thermocline is located at a water depth of ~20-40 m. Cluster analysis revealed three water depth ranges in the lake of importance to ostracode distribution: 1) littoral zone (0.1-3 m), 2) water depths from the base of the littoral zone to the base of the thermocline (3-40 m), and 3) water depths below the thermocline (40-160 m). The assemblage Darwinula-Heterocypris-Pseudocandona-Strandesia is characteristic of waters <15 m. The Cypridopsis-Cytheridella-Limnocythere assemblage characterizes waters <40 m and Physocypria indicates waters >40 m. Ostracode taxa from Lago Petén Itzá show specific ecological preferences related to water depth and associated physico-chemical characteristics, thus illustrating the potential of ostracodes as indicators of lake level changes and hydrodynamics.
Zootaxa 3630 (2): 270–290 www.mapress.com/zootaxa/ Article http://dx.doi.org/10.11646/zootaxa.3630.2.4 http://zoobank.org/urn:lsid:zoobank.org: Abstract Five different species of Copepoda were extracted from a leaf litter sample collected on the top (at 2000 m a.s.l.) of a cloud forested mountain in El Cusuco National Park, Honduras. Three of them, one Cyclopidae and two Canthocamptidae are new to science, and are described herein. Olmeccyclops hondo sp. nov. is the second representative thus far known of this New World genus. Moraria catracha sp. nov. and Moraria cusuca sp. nov. are the first formally described members of the genus occurring in Central America. The concept of a " Moraria-group " is considered to be an artificial grouping and is limited here to the genera Moraria and Morariopsis only. The distributional range of this group is essentially Holarctic, with the mountainous regions in Honduras, and probably in west Nicaragua, as the southernmost limits in the New World.
New records are listed for several continental species of free-living cyclopoid and harpacticoid copepods (Crustacea) from Mexico, Guatemala, and Colombia. Diacyclops hispidus n. sp. and Nitocra lacustris colombianus n. ssp. are described from Colombia. The setation formula of Elaphoidella suarezi is corrected.
Tropocyclops jamaicensis n. sp. is the most numerous copepod and frequently the most numerous metazoan of phytotelmata in leaf axils of terrestrial bromeliads of the Cockpit Country, Jamaica. Distinctive apomorphies of this species, particularly the naked pediger 5 and the 2 setae on leg 5, necessitate emending the diagnosis of the genus Tropocyclops. Tropocyclops jamaicensis occurred in 63% of bromeliads sampled, but the next most numerous copepod, Ectocyclops phaleratus, occurred in 17.5%. In colonization experiments, T. jamaicensis, along with ostracodes and chironomid and mosquito larvae, invaded some plants within 2 to 5 weeks. After 13 weeks, 8 of 10 plants harbored populations of this copepod.
The studies on marine copepods of Costa Rica started in the 1990's and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a mod-erate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the ZooKeys 457: 15–33 (2014)
The planktonic copepod crustacean Arctodiaptomus dorsalis (Marsh) was found in ponds at two warmwater-fish hatcheries in Virginia in the summer of 2006. Because no permanent population is known to exist north of Florida in the eastern United States, the Virginia populations are considered to be introduced. These discoveries provided the impetus for a review of the distribution of this species, based on previously published records, as well as unpublished records derived from museum collections and inquiries of colleagues. This review provided new evidence that the core range of A. dorsalis lies in tropical and subtropical lowlands bordering the Gulf of Mexico and Caribbean Sea, from the southern United States through Central America and northern South America, plus the Greater Antilles. There are outlying, published records from Arizona, California, Missouri, Oklahoma, South Carolina, Texas, and Virginia in the United States; the Central Highlands of Mexico; and the Colombian Highlands. Previously unpublished records from Arkansas, Florida, Indiana, Maryland, Michigan, Oklahoma, Texas, Puerto Rico, and Colombia are given herein. Several of the outlying populations were likely established through human agency, via transport of fish or aquatic plants; at least one population, in South Carolina, did not persist. The species has become established in the south-central Mississippi River basin, from Texas as far north as Missouri, and possibly also in Indiana and southern Michigan, primarily in eutrophic impoundments and fish hatcheries although it is not known whether all of the populations previously reported in the region have survived. The population in Indiana has apparently persisted since at least 1980. These observations suggest that Arctodiaptomus dorsalis has the potential to extend its range farther north and south, into suitable, eutrophic waterbodies, aided by inadvertent local introductions. Cases of intercontinental introductions of copepods are briefly reviewed.
From a series of biological samples collected from different freshwater environments in Costa Rica, Central America, the exotic Asian cyclopoid Mesocyclops thermocyclopoides Harada, 1931 was identified. We analyzed the morphology and appendage ornamentation of different Neotropical populations of this species, including specimens from Honduras, southeastern Mexico, and Costa Rica. We also examined Asian specimens from Taiwan, Indonesia, Vietnam, and Thailand, and performed a comparison of the Neotropical and Asian populations including a Principal Component Analysis (PCA). The Neotropical and Asian specimens show subtle morphological variations in the antennules, antennae, mandibles, swimming legs 1-4, and fifth legs. Some characters in the Neotropical group appear to diverge from the Asian pattern and the PCA indicated that intercontinental populations of M. thermocyclopoides are far from being homogeneous. These intra-specific differences are described to expand the known morphological range of this species and to provide the first comparative analysis of an exotic copepod in the Americas. Our analysis suggests that the geographic isolation of the American populations and the subtle morphological divergences with respect to the Asian patterns could be related to speciation processes in the Neotropical region, but also intra-Asian differences are reported. In the Neotropical region this species appears to be restricted to southeastern Mexico, Central America, and one Caribbean island; its potential as biological control of mosquito might enhance its spread in the region.
Introduction
Diaptomid copepods are prevalent throughout continental waters of the Neotropics, yet little is known about their biogeography. In this study we investigate the main biogeographical patterns among the neotropical freshwater diaptomid copepods using Parsimony Analysis of Endemicity (PAE) based on species records within ecoregions. In addition, we assess potential environmental correlates and limits for species richness.
Results
PAE was efficient in identifying general areas of endemism. Moreover, only ecoregion area showed a significant correlation with diaptomid species richness, although climatic factors were shown to provide possible upper limits to the species richness in a given ecoregion.
Conclusion
The main patterns of endemism in neotropical freshwater diaptomid copepods are highly congruent with other freshwater taxa, suggesting a strong historical signal in determining the distribution of the family in the Neotropics.
A biogeographic regionalisation of the Neotropical region is proposed as a hierarchical classification of sub-regions, dominions, provinces and districts. This regionalisation is based on biogeographic analyses of terrestrial plant and animal taxa, and seeks to provide universality, objectivity and stability, such that it can be applied when describing distributional
areas of particular taxa or comparing different biogeographic analyses. The Neotropical region is currently comprised of three sub-regions (Antillean, Brazilian and Chacoan), two transition zones (Mexican and South American), seven dominions (Mesoamerican, Pacific, Boreal Brazilian, Southwestern Amazonian, Southeastern Amazonian, Chacoan and Parana)
and 53 provinces. For some of the latter, sub-provinces and districts are recognized. Complete synonymies and brief descriptions of the areas are provided, as well as the endemic taxa that diagnose the different provinces.
A comprehensive, but simple-to-use software package for executing a range of standard numerical analysis and operations used in quantitative paleontology has been developed. The program, called PAST (PAleontological STatistics), runs on standard Windows computers and is available free of charge. PAST integrates spreadsheettype data entry with univariate and multivariate statistics, curve fitting, time-series analysis, data plotting, and simple phylogenetic analysis. Many of the functions are specific to paleontology and ecology, and these functions are not found in standard, more extensive, statistical packages. PAST also includes fourteen case studies (data files and exercises) illustrating use of the program for paleontological problems, making it a complete educational package for courses in quantitative methods.
Chironomids, diatoms and microcrustaceans that inhabit aquatic ecosystems of the Northern Neotropics are abundant and diverse. Some species are highly sensitive to changes in water chemical composition and trophic state. This study was undertaken as a first step in developing transfer functions to infer past environmental conditions in the Northern lowland Neotropics. Bioindicator species abundances were related to multiple environmental variables to exploit their use as environmental and paleoenvironmental indicators. We collected and analyzed water and surface sediment samples from 63 waterbodies located along a broad trophic state gradient and steep gradients of altitude (approximately 0-1 560 m.a.s.l.) and precipitation (approximately 400-3200 mm/y), from NW Yucatán Peninsula (Mexico) to southern Guatemala. We related 14 limnological variables to relative abundances of 282 diatom species, 66 chironomid morphospecies, 51 species of cladocerans, 29 non-marine ostracode species and six freshwater calanoid copepods. Multivariate statistics indicated that bicarbonate is the strongest driver of chironomid and copepod distribution. Trophic state is the second most important factor that determines chironomid distribution. Conductivity, which is related to the precipitation gradient and marine influence on the Yucatán Peninsula, is the main variable that shapes diatom, ostracode and cladoceran communities. Diatoms, chironomids and cladocerans displayed higher diversities (H = 2.4-2.6) than ostracodes and copepods (H = 0.7-1.8). Species richness and diversity were greater at lower elevations (< 450 m.a.s.l.) than at higher elevations in Guatemala. Distribution and diversity of bioindicators are influenced by multiple factors including altitude, precipitation, water chemistry, trophic state and human impact.
The free-living continental copepod fauna of the Yucatan Peninsula has been studied for decades; recent intensive surveys suggest that its biodiversity is higher than formerly realized. An updated, revised checklist of the Yucatan copepods is provided herein. This new list includes 59 species, more a than 30% increase from the most recent previous account. The Yucatan Peninsula has long been considered to have faunistic affinities with Central and Southern Mexico and with South America. A similarity analysis was performed using regional records of Copepoda and including two taxa, the orders Calanoida and Cyclopoida. Results from both groups suggest that the Yucatan copepod fauna diverges from that of Central Mexico. Central Mexico itself seems to be closest to the upper Central American fauna, an affinity explained by a longer geological connection. Overall, the Yucatan copepod fauna appears to have more biogeographic ties with Cuba and the insular Caribbean than with Central America or the rest of Mexico. The occurrence of nearctic diaptomids such as Arctodiaptomus and Leptodiaptomus in the Yucatan seems to be related to a general invasion of these calanoids that reached Central America and intermittently spread into the Yucatan Peninsula. With two endemic species in the Yucatan, Mastigodiaptomus appears to have become diversified in the peninsula, derived from other neotropical forms. The local high proportion of endemic forms of Copepoda and the particular geological history of the Yucatan make this karstic area a peculiar, separate entity within the neotropical region that should be studied in more detail.
Cryptic species are organisms that look identical but represent distinct evolutionary lineages. They are an emerging trend in organismal biology across all groups, from flatworms, insects, amphibians, and primates, to vascular plants. This book critically evaluates the phenomenon of cryptic species and demonstrates how they can play a valuable role in improving our understanding of evolution, in particular of morphological stasis. It also explores how the recognition of cryptic species is intrinsically linked to the so-called species problem, the lack of a unifying species concept in biology, and suggests alternative approaches. Bringing together a range of perspectives from practising taxonomists, the book presents case studies of cryptic species across a range of animal and plant groups. It will be an invaluable text for all biologists interested in species and their delimitation, definition, and purpose, including undergraduate and graduate students and researchers.
Elpidium ostracods are known by their very particular niche (water accumulated in tank-bromeliads), their relatively low dispersal ability and their dependency on amphibians for dispersal and colonization of new bromeliads. All these characteristics make the genus an interesting group for evolutionary, ecological and even taxonomic studies. However, the diversity of the group remains poorly studied. Here, we describe three new species of Elpidium, Elpidium littlei n. sp., Elpidium heberti n. sp. and Elpidium wolfi n. sp., and re-describe Elpidium laesslei, all from Jamaica. These species are characterized by a copulatory process with separated ejaculatory duct and distal glans, a feature so far unique within the genus. Each species can, in turn, be diagnosed by soft part and carapace morphology, most notably comparing hemipenis, valve ornamentation and degree of sexual dimorphism. The observed morphological diversity of Elpidium is discussed in relation to previous genetic estimates that suggested an even higher diversity in Jamaica. We point to intraspecific variation and lack of complete morphological descriptions as possible explanations. We also reaffirm the need of multidisciplinary studies in order to do more objective and secure taxonomic classifications in future studies.
Previous studies of plankton from Guatemala lakes, by Meek (1908); Clark (1908); and Tilden (1908); have been purely qualitative in nature. Juday's (19,16) limnological study of Lake Amatitlan, however, included a single series of quantitative plankton collections at various depths. The present paper is a report on a series of quantitative collections taken from Lake AmatitIan over an eight-week period during the summer of 1951. General description of the lake.-Lake Amatitlan is of volcanic origin and is situated at 90030' west longitude and 14025' north latitude in the Republic of Guatemala. It is eight miles long, 21/2 miles wide and with a surface of 3870 feet above sea level. A crossing of the International Railways of Central America divides the lake into two basins. Mountains, 4670-5170 feet above sea level, surround the lake; those of the northwest are composed of granite; the others are principally of volcanic ash, pumice, and other loose materials which are easily eroded. The mountains to the north and northwest show evidence of erosion in the form of huge cuts which are visible for several miles. Entering the lake on the north side is the Villalobos (Lobos) River, which is the main affluent stream during the dry season. The single outlet is the Michatoya River which drains the northwest basin from the south. The greater part of the lake shore is steep, especially to the east and southeast. Half or more of the north and northeast shores consist of a broad, low plain which 'has been built up by the LoSos River and temporary streams which enter the lake from the north and northwest during the rainy season (MayNovember).
For more than a century, the two largest bodies of water in Nicaragua, Lake Nicaragua and its smaller companion, Managua, have engaged naturalists from several disciplines. Perhaps their appeal has been as curiosities because of the occurrence of fish with marine affinities in the larger lake, especially a dangerous shark. The charm has been in Nicaragua or Cocibolca, rather than Managua, properly called Xolotlán. Even though the latter is saltier, it has no elasmobranchs or tarpons. The lakes, and specifically the larger, cover the greatest expanse of any body of water between Lake Titicaca, Bolivia-Peru, and the Laurentian Great Lakes 35° farther north. Despite this, very little limnologic work has been published concerning them.
Their story began 500 million years ago, but we only started to get to know them in 1746, when Linné described the first ostracod species. Vividly portraying the freshwater ostracods, this comprehensive reference work gathers the knowledge gained during some 250 years, but which to date has remained scattered throughout the literature. It starts with an introduction to the class Ostracoda with a special focus on freshwater ostracods and highlights practical methods in their study. The systematic part includes an introduction to all families; identification keys for all subfamilies, genera and species; diagnoses for each subfamily and genus; and lists of synonyms and distribution of species. The text is richly illustrated with distribution maps, line drawings of key generic characteristics, and numerous SEM photographs. Serving as an excellent starting point for all further research on freshwater ostracods, it can be widely used not only by ostracodologists, but also by crustaceologists, evolutionists and ecologists. © Springer-Verlag Berlin Heidelberg 2012. All rights are reserved.
CRUSTACEANS A N D ROTIFERS O F T H E "LAGUNA DEL TESORO" (CUBA) I n this paper a listof aquaticCrustacea and Rotatoria recorded during a visit to "Laguna del Tesoro" in Jannuary of 1983 is presented. The lagoon is situated in [he North-Easr of the "Cienaga de Zapata". The waters are fresh chloride-alkaline and cover on area of 700 Ha. The Rotifera and Crustacea's community is very rich in species; 13 Rotatoria, 20 Entomostraca and a Amphipoda have been identified. Thecommunity is divided into two very clear subcommunities: a planktonicand a heleoplanktonicone. The he!eoplanktonic community is found in the abundant macrophytic vegetation, and is particularly interesting due to its complexity and especies. The biology of some of these species as CycLertheria hislopi, Chydorus cilzatus and Microcyclops ceibaenrir, is not well known.
Over the past decade, the availability of DNA sequence data from rotifers and the development of statistical and analytical tools linked to phylogenetic reconstructions allowed researchers to deepen our knowledge of patterns and processes in rotifer diversity. Here, I review the recent rotifer literature regarding: (i) the position of rotifers in the animal kingdom, with the wide consensus being within Spiralia, in a clade called Platyzoa together with Acanthocephalans, Gastrotricha, Gnathostomulida, Micrognathozoa, and Platyhelminthes; (ii) the still unresolved phylogenetic relationships within rotifers and the disputed position of Acanthocephala; (iii) the discovery of extensive hidden diversity through DNA taxonomy; (iv) phylogeography; and (v) the phylogenetic structure of rotifer communities. In order to facilitate the further discovery of hidden diversity in rotifers, I provide a simple tutorial on the currently available methods in DNA taxonomy from single locus data using a previously published rotifer dataset as an example. Moreover, I outline a brief perspective on the potentiality of the use of phylogenetic approaches in future rotifer studies.
Gut contents of 1150 adults of Apocyclops panamensis were examined to obtain information on its feeding habits in extensive shrimp ponds during a 16-week period (10 June-5 Sept. 1999). Temporal changes in the relative abundance of ingested algae were studied and compared with the natural phytoplankton assemblage in the pond. The phytoplankton community was comprised of diatoms and blue-green and green algae; total abundance varied between 1.11 × 104 and 10.2 × 104 cells/ml, of which blue-green algae, such as Lyngbya limnetica, Spirulina nodosa, and Anabaenopsis sp., were the most abundant. During the study period, diatoms made up 89% of the algal cells consumed by A. panamensis. Among the diatoms, Nitzschia sp. was most important, while Navicula sp. and Amphora ovalis were also substantial. The green alga, Chlorella sp., accounted for 10.6%; blue-green algae were rarely consumed.
Lakes Nicaragua and Managua are large, rather shallow, fresh-water bodies that lie in a late Tertiary and Quaternary graben in western Nicaragua. The bottom sediments comprise highly organic diatomaceous volcanic silts and clays in which quartz plagioclase feldspar, dioctahedral montmorillonite and volcanic glass are the principal constituents. Organic nitrogen content of the lake sediments ranges from 0.3-1.2 percent, about the same range as in eutrophic lakes of higher latitudes. Bitumen content is rather low, much like that of oligotrophic lakes. Hydrocarbon fractions of bitumens are similar in amount to an alkaline lake of western U. S. Non-hydrocarbon bitumens are high in proportion to hydrocarbons. Carbohydrates and amino acids sre similar in amount to those of eutrophic lake sediments. Chlorinoid pigments are similar to but flavinoid pigments are less than the typical pigments in eutrophic lake sediments. Studies of the pH, Eh, inorganic composition and organic chemical and fossil residues of the lake sediments indicate that they are moderately productive, early eutrophic or mesotrophic lakes. Despite the presence of elasmobranches and of several marine or brackish-water types of invertebrates, no definite evidence of former marine connection has been found in the sediments. It is suggested that the lakes have been fresh-water for all or nearly all of their history and may be a little more highly mineralized now than formerly.