Anchialine podocopid Ostracoda of the Galapagos Islands

Water-filled fissures and lava tubes on Isla Santa Cruz and Isla Isabela provide anchialine habitats for 11 species of podocopid and platycopid Ostracoda, most with Atlantic and West Indian affinities. Their ancestors may have been carried to earlier islands in the Galapagos system by trans-Isthmian currents, on vegetation or larger animals, or by migrating waterfowl. None are derived from present-day Pacific coastal faunas of North, Central or South America. Two species of Cytheracea, a new species of Anchistrocheles (Bairdiacea), and one of Cytherella (Platycopida) are described.     

Revision of the family Pontocyprididae (Ostracoda), with new anchialine species and genera from Galapagos Islands

Iliffeoecia iliffei and Kareloecia woutersi are new argilloeciine and propontocyprididine genera and species from anchialine habitats in Galapagos Islands, whose specializations for interstitial or cryptic life show convergence with Comontocypris. Ekponlocypris, Schedopontocypris and the new genus Thomontocypris are removed from Propontocypris. Eighty-three living species of Pontocyprididae, for which the soft anatomy has been described, provide the basis for emended generic diagnoses and a revised classification.     

Anchialine Gyprididae (Ostracoda) from the Galapagos Islands, with a review of the subfamily Paracypridinae

The five species of Cyprididae collected from anchialine habitats of the Galapagos Islands include Paracypris crispa, previously described from marine caves and reefs on Bermuda, and the freshwater species Strandesia stocki, which is widely distributed in wells of the West Indies. Three new species, Dolerocypria ensigera, Mungava recta and Hansacypris galapagosensis, contribute to more precise understanding of these circumtropical genera. A review of known soft-anatomical characters for 68 species of Paracypridinae, five of which are transferred to different genera, reveals too many inconsistencies for a simple hypothesis. The current classification of Paracypridinae into three tribes and 18 genera may be overly subdivided, and elevation of Paracypridinae to family rank is not warranted.     

The grasses Urochloa multiculma and U. fusca (Poaceae) in the Galapagos archipelago

Abstract

Confusion has existed over the validity of the taxon Urochloa multiculma (Andersson) Morrone & Zuloaga, which was originally described from Galapagos, and over the presence in the islands of the closely related U. fusca (Sw.) B.F. Hansen & Wunderlin. An examination of 14 characters in 182 specimens leads to the conclusions that U. multiculma is a valid taxon endemic to Galapagos, and that U. fusca is probably a recent human‐mediated introduction to the archipelago, which may now be hybridising with multiculma. Leaf pubescence and spikelet structure are used to construct an identification key.     

Seals of the Galapagos Islands

The Galapagos archipelago has been colonized by two species of otariid, the fur seal, Arctocephalus galapagoensis , and the sea lion, Zalophus californianus wollebaeki. The former probably arrived from South America and the latter from North America, both by way of periodic incursions of colder water forming the east Pacific corridor. The terrestrial behaviour of both these otariids is affected by the high ambient temperatures in the Galapagos Patterns of breeding behaviour of otariids which lead to intense polygyny and sexual dimorphism appear to be modified. The habit of prolonging lactation, widespread in otariids, is carried to an extreme in the Galapagos fur seal. The reason for this is unclear.     

Termites (Isoptera: Kalotermitidae,Rhinotermitidae, Termitidae) of Ecuador

Termites are an abundant and diverse group in the Neotropics with about 500 species representing 83 genera. The paucity of the termite fauna recorded from Ecuador is due, in part, to a lack of deliberate surveys. We revise the termite fauna of Ecuador and raise the number of species from 25 species to 72 based on our recent termite surveys. Of the 72 species, 18 could not be conclusively identified and are likely new species. Given the limited area that has been covered in surveys of the Ecuadorian termite fauna, there are undoubtedly many more species to be recorded for Ecuador, primarily in the eastern lowland areas, cloud forests on both the eastern and western slopes of the Andes, and the Amazonian lowland forests.     

Presence of Chame Dormitator latifrom (Richardson, 1844) (Pisces: Eleotridae) in the Galapagos Islands, Ecuador

Six specimens of Dormitator latifrons caught in Laguna del Cementerio, Isabela Island, represent the first record of this species in the Galapagos Islands.     

Denitrification in Bahia Darwin (Galapagos Islands) an intermittent anoxic basin in the tropics

Changes in oxygen and nitrate in Bahia Darwin between July 1968 and March 1969 indicate that denitrification occurred in the deeper waters of this tropical, intermittently anoxic basin. Assuming constant rates of oxidation of organic matter in equally spaced depth intervals below the pycnocline depth, the rate of denitrification was estimated to be about 62.0 µg-atom NO₃-N/liter/year. This rate is attributable to denitrification in the water column because a smaller rate was estimated for strata closer to the sediment water interface.Contribution No. 3193 from the Woods Hole Oceanographic Institution. Woods Hole, Massachusetts 02543. This study was supported in part by the National Science Foundation Grants GA 29303 and GB 6870. Reprints should be requested from the second author.     

Cuticular hydrocarbons of grasshoppers from the Galapagos Islands, Ecuador

Cuticular lipids of adult Schistocerca literosa, Schistocerca melanocera and Halmenus robustus were analyzed. They have a similar range of hydrocarbons to those previously reported for other grasshoppers, but contain significant amounts of squalene which has not previously been reported from grasshopper cuticle. In Halmenus, squalene comprises 17% of the total hydrocarbons, while internally branched methylalkanes are present in much smaller quantities than in other grasshoppers. The results lend no support for a close taxonomic link between Halmenus and Schistocerca.     

Life history of the slipper lobster Scyllarides astori Holthuis 1960, in the Galapagos islands, Ecuador

Growth of the scyllarid lobster Scyllarides astori was estimated in the Galapagos Marine Reserve by use of tag-recapture data and analysis of length-frequency distributions. Asymptotic carapace lengths (CL_∞), obtained from Powell-Wetherall plots, were 17.53 cm for males and 16.38 cm for females. A ‘forced’ Gulland-Holt plot gave growth constants (K) of 0.153 yr^− 1 for males and 0.162 yr^− 1 for females. The narrow size distribution suggests that juveniles occupy a different spatial niche and that adult growth is either very slow or that there is a terminal moult. Currently mainly used for local consumption, there is pressure to allow exportation of S. astori on a large scale to continental Ecuador and abroad. However, its slow growth and low abundance point to the need for a cautious approach and the implementation of clear and enforceable regulations in order to ensure the biological and economical sustainability of the population.     

Past,current, and future trends of red spiny lobster based on PCA with MaxEnt model in Galapagos Islands,Ecuador

In order to enhance in terms of accuracy and predict the modeling of the potential distribution of species, the integration of using principal components of environmental variables as input of maximum entropy (MaxEnt) has been proposed in this study. Principal components selected previously from the principal component analysis results performed in ArcGIS in the environmental variables was used as an input data of MaxEnt instead of raw data to model the potential distribution of red spiny lobster from the year 1997 to 2015 and for three different future scenarios 2020, 2050, and 2070. One set of six original environmental variables pertaining to the years 1997–2015 and one set of four variables for future scenarios were transformed independently into a single multiband raster in ArcGIS in order to select the variables whose eigenvalues explains more than 5% of the total variance with the purpose to use in the modeling prediction in MaxEnt. The years 1997 and 1998 were chosen to compare the accuracy of the model, showing better results using principal components instead of raw data in terms of area under the curve and partial receiver operating characteristic as well as better predictions of suitable areas. Using principal components as input of MaxEnt enhances the prediction of good habitat suitability for red spiny lobster; however, future scenarios suggest an adequate management by researches to elaborate appropriate guidelines for the conservation of the habitat for this valuable specie with face to the climate change.     

Origin and dispersion pathways of guava in the Galapagos Islands inferred through genetics and historical records

Guava (Psidium guajava) is an aggressive invasive plant in the Galapagos Islands. Determining its provenance and genetic diversity could explain its adaptability and spread, and how this relates to past human activities. With this purpose, we analyzed 11 SSR markers in guava individuals from Isabela, Santa Cruz, San Cristobal, and Floreana islands in the Galapagos, as well as from mainland Ecuador. The mainland guava population appeared genetically differentiated from the Galapagos populations, with higher genetic diversity levels found in the former. We consistently found that the Central Highlands region of mainland Ecuador is one of the most likely origins of the Galapagos populations. Moreover, the guavas from Isabela and Floreana show a potential genetic input from southern mainland Ecuador, while the population from San Cristobal would be linked to the coastal mainland regions. Interestingly, the proposed origins for the Galapagos guava coincide with the first human settlings of the archipelago. Through approximate Bayesian computation, we propose a model where San Cristobal was the first island to be colonized by guava from the mainland, and then, it would have spread to Floreana and finally to Santa Cruz; Isabela would have been seeded from Floreana. An independent trajectory could also have contributed to the invasion of Floreana and Isabela. The pathway shown in our model agrees with the human colonization history of the different islands in the Galapagos. Our model, in conjunction with the clustering patterns of the individuals (based on genetic distances), suggests that guava introduction history in the Galapagos archipelago was driven by either a single event or a series of introduction events in rapid succession. We thus show that genetic analyses supported by historical sources can be used to track the arrival and spread of invasive species in novel habitats and the potential role of human activities in such processes.     

Human activity can influence the gut microbiota of Darwin's finches in the Galapagos Islands

The gut microbiota of animal hosts can be influenced by environmental factors, such as unnatural food items that are introduced by humans. Over the past 30 years, human presence has grown exponentially in the Galapagos Islands, which are home to endemic Darwin's finches. Consequently, humans have changed the environment and diet of Darwin's finches, which in turn, could affect their gut microbiota. In this study, we compared the gut microbiota of two species of Darwin's finches, small ground finches (Geospiza fuliginosa) and medium ground finches (Geospiza fortis), across sites with and without human presence, where finches prefer human‐processed and natural food, respectively. We predicted that: (a) finch microbiota would differ between sites with and without humans due to differences in diet, and (b) gut microbiota of each finch species would be most similar where finches have the highest niche overlap (areas with humans) compared to the lowest niche overlap (areas without humans). We found that gut bacterial community structure differed across sites and host species. Gut bacterial diversity was most distinct between the two species at the site with human presence compared to the site without human presence, which contradicted our predictions. Within host species, medium ground finches had lower bacterial diversity at the site with human presence compared to the site without human presence and bacterial diversity of small ground finches did not differ between sites. Our results show that the gut microbiota of Darwin's finches is affected differently across sites with varying human presence.     

Evolution and adaptations of Galapagos sea-birds

With two endemic genera, 26% endemism at the specific, and 58% endemism at the subspecific level, the Galapagos sea-bird fauna is more highly endemic than that of any other archipelago. Of the four most distinct, hence probably oldest, endemics, three are probably of north Pacific origin and the fourth may be. The next most distinct group is of Humboldt Current origin, and the remainder, which are very little differentiated, are of Pacific or Caribbean origin. Special adaptations to Galapagos conditions include the loss of flight by a cormorant and the evolution of nocturnal habits by a gull, the latter probably as a result of kleptoparasitism or nest-predation by frigatebirds. As a group the Galapagos sea-birds show varied adaptive responses to the relatively ascasonal and highly unpredictable marine environment. Opportunistic and non-annual breeding regimes predominate. Unlike the Galapagos land-birds, the study of Galapagos sea-birds has thrown light not on speciation processes but on the consequences of natural selection acting on breeding ecology and associated behaviour.     

Distribution patterns of freshwater Ostracoda (Crustacea) in the Canary Islands with regards to habitat use and biogeography

In this study biogeographic patterns and habitatrelationships of freshwater Ostracoda wereinvestigated in the Canary Island archipelago. Mostdata were collected from published studies, thoughalso new data from Gran Canaria are presented. In all,22 freshwater species are presently known to theCanaries. Six species, viz. Ilyocypris bradyi,Cypris bispinosa, C. pubera, Herpetocypris chevreuxi, Heterocyprisincongruens, and Sarscypridopsis lanzarotensisare new to Gran Canaria, the first two also being newto the Canaries in general. Testing the influence ofa number of variables on faunal richness indicatedonly a weak association with island area. Distancesbetween islands also proved not significant, and sodid other properties of islands, including age,altitude and precipitation. This was in contrast to acomparison set of data comprising aquatic beetles.Like beetles, however, ostracods did not show a nestedpattern, i.e. faunas of species-poor islands were notsubsets of species-rich island faunas. By having lowendemicity (endemic species lacking in the Canaries),the ostracod fauna resembled island fern floras. Bothgroups of organisms have tiny diaspores (diameter<0.1 mm) and are extensively parthenogeneticsuggesting similar dispersal and founder mechanisms.We identified a pattern (with one exception), wherethose species with distributions extending acrossseveral islands also had wider within-islanddistributions. Many species showed affinities todifferent habitats depending on conductivity of water,altitude and habitat types: whether they werepermanent or temporary, hypogean or epigean, orcharacterized by running or stagnant waters.     

Marine Ostracoda from Pitcairn, Oeno and Henderson Islands

All of the samples yielded podocopid ostracods. Most of the faunas from Pitcairn and Oeno were poorly preserved and sparse; those from Henderson were much more abundant, more diverse and better preserved. Only 33 species are recorded from the joint fauna and this may reflect the limited number of environments sampled or the remote geographical situation of the islands. At least 20 species (and a new genus) are restricted to the islands. Other species are known from the Solomon Islands, Australia and Indonesia. Of a considerable number of Indo-Pacific pandemic species, only three Kotoracythere inconspicua (Brady), Tenedocythere transoceanica (Teeter) and Triebelina sertata (Triebel) have been identified to date. The fauna is not, however, nearly so endemic as that of Easter Island on which the two authors are currently working.     

Relationships of the Galapagos flora

Joseph Dalton Hooker's pioneer 1847 paper on Galapagos plants and their relationships is a classic in the field of phytogeography. It was the first study of its kind to be published, comparing the islands' flora with island and continental floras elsewhere, hypothesizing on the dispersal mechanisms of the plants, and pointing out anomalies in the inter-island distributions of the native species. These are still three of the primary concerns of contemporary phytogeographers, and the present paper contrasts Hooker's findings with those of today. Despite the accumulation of a large amount of data since his time, many of Hooker's conclusions regarding Galapagos phytogeography remain valid.     

First record of a spawning aggregation for the tropical eastern Pacific endemic grouper Mycteroperca olfax in the Galapagos Marine Reserve

This study provides direct and indirect evidence of temporally and spatially consistent spawning aggregations for the grouper Mycteroperca olfax. Recently reported declines in population numbers, probably related to the direct targeting of aggregations by artisanal fishermen, highlight the urgent need for species‐specific management actions in the Galapagos Marine Reserve, such as minimum and maximum landing sizes, and the importance of protecting key aggregation sites with the declaration of no‐take areas and the establishment of total fishing bans during the reproductive season.