Total Fauna Research Articles

Patterns of diversity, endemism and distribution of bees (Insecta: Hymenoptera: Anthophila) in southern Africa

Abstract For southern Africa, patterns of bee diversity and endemism were studied with a special focus on South Africa and the Cape Floral Kingdom. Based on distribution records of 645 species incorporated in the “Southern African Bee Database” (SouthABees), the pattern of bee diversity was analysed on a 2° × 2° grid. The resulting map shows a bicentric pattern, with highest species diversity located in the arid west and in the relatively moist east. The investigation of distribution patterns of 516 South African species identified twelve distribution types that largely coincide with patterns in the seasonality of precipitation: winter rainfall, early to mid summer rainfall, late to very late summer rainfall and rain all year. The largest number of bee species is associated with the winter rainfall area (46.3% of the fauna) and with the early to mid summer rainfall area (36.5% of the fauna). Consequently South Africa is a centre of bee diversity of global significance. The most important centres of endemism are the winter rainfall area in the west (27.3% of total fauna endemic) and the early to mid summer rainfall area (29.1% of total fauna endemic) in the east. The relationship between bee/plant diversity patterns and speciation is discussed.

Distribution patterns of free-living nematodes in differently degraded river reaches of the River Wien, Austria

AbstractFree-living nematode communities were investigated at four morphologically different reaches along the River Wien, Austria. A near natural (NN) reach, two impounded reaches of different size (small and large: SI, LI) and a restored reach (RR) were sampled in autumn, winter, spring and summer (2004-2005). A total of 4144 individuals were counted and comprised 78 species. Nematodes of the impounded sites contributed least (5% at SI) and most (60% at LI) to the total fauna. Mean site abundances (ind./10 cm2) were 68, 27, 10 and 1 at RR, NN, LI and SI, respectively. Species diversity ranged from 1.59 at LI to 2.16 at RR. Bacterivorous nematodes dominated all sites (>50%); only algivorous Chromadoridae represented a high percentage contribution (46%) at LI. Based on this high portion, the maturity index (MI 1-5) was highest at this site (2.61). The MI indicated status of good water quality for the NN (2.5). The relatively low MI (2.10) and the high portion of cp1 Secernentea (14%) reflect the status of critical pollution at the restored site. The patterns of average taxonomic distinctness (ATD) did not optimally reflect habitat quality; a better descriptor of degraded river habitats seems to be the variation of taxonomic distinctness (VTD) in this study. In conclusion, the MI seems to be a better descriptor of pollution and the VTD of morphological degradation.

Jurassic and Cretaceous Gastropods from Hydrocarbon Seeps in Forearc Basin and Accretionary Prism Settings, California

Fourteen gastropod species from 16 Mesozoic hydrocarbon seep carbonate deposits of the Great Valley Group and Franciscan Complex in California are described. Two genera are new: Bathypurpurinopsis has a fusiform shell with a siphonal fold, and variable Paskentana has turbiniform or littoriniform shells with spiral and/or scaly sculpture and convex or shouldered whorls. Due to the lack of data on shell microstructure and protoconch morphology, many of our taxonomic assignments have to remain tentative at present. Species that are described as new include: Hokkaidoconcha bilirata, H. morenoensis, H. tehamaensis (Hokkaidoconchidae). Abyssochrysos? giganteum (Abyssochrysidae?), Paskentana globosa, P. berryessaensis. and Bathypurpurinopsis stantoni (Abyssochrysoidea, family uncertain). The total fauna represents a mixed bag of taxa that were: (i) widely distributed during the late Mesozoic (Amberleya); (ii) restricted to late Mesozoic seep carbonates in California (Atresius, Bathypurpurinopsis, Paskentana); and (iii) members of seep/deep-sea groups with a long stratigraphic range (abyssochrysids, hokkaidoconchids).

Soil and litter fauna of cacao agroforestry systems in Bahia, Brazil

Agroforestry systems deposit great amounts of plant residues on soil and this leads to high levels of soil organic matter content and has increased soil biodiversity and improved its conservation. This study compares the distribution of meso and macrofaunal communities in soil and litter under cacao agroforestry systems and in a natural forest in the southern Bahia state of Brazil. Soil and litter samples were obtained in September 2003, February 2004, and August 2004 in five cacao agroforestry systems. The systems evaluated included: cacao renewed under Erythrina sp. (Erythrina poeppigiana) (CRE); cacao renewed under natural forest (Cabruca, CRF); an old cacao system under Erythrina sp. (OCE); an old cacao system under a natural forest system (Cabruca, OCF) and a cacao germplasm collection area (CGC). As a reference soil and litter under a natural forest (NF) was included. Organisms were collected over a 15-day period with a Berlese–Tullgren apparatus. The density and richness of total fauna varied distinctly according to sites, sampling time and material sampled (soil and litter). 16,409 of fauna were recovered from soil and litter samples and the density of total fauna was 2,094 individuals m−2 in the litter and 641 individuals m−2 in the soil. The richness was 11.8 in the litter and 7.5 in the soil. The cacao agroforestry systems adopted for growing cacao in the southern Bahia region of Brazil have beneficial effects on the soil and litter faunal communities, and such systems of cacao cultivation could be considered as a conservation system for soil fauna. The development of a litter layer resulted in higher abundance and diversity of soil fauna.

Mesofauna associated with the marine sponge Amphimedon viridis. Do its physical or chemical attributes provide a prospective refuge from fish predation?

Marine sponges often harbor an abundance of associated organisms. We characterized mesofauna associated with the common tropical sponge Amphimedon viridis, and then tested whether physical (spicules) or chemical (lipophilic or hydrophilic extracts) properties of this sponge provide a prospective refuge for mesofauna from fish predation. Sponge analyses revealed a moderately diverse and numerically rich community of sponge-associated mesofauna comprised primarily of mesocrustaceans (82% of total fauna). Eighty-nine percent of these were amphipods, but smaller numbers of tanaids, decapods , and isopods also occurred. Quantitative sampling of outer surfaces and interstices of fifteen A. viridis yielded a total mean ± 1 SD density of sponge–associated mesofauna of 53 ± 9.3 individuals per 100 cm 3 wet sponge tissue. Among the numerically dominant amphipods, 65% occurred on outer sponge surfaces where they are most vulnerable to fish predators. We evaluated whether A. viridis provides a prospective refuge from predation by assessing the palatability of this sponge to the sympatric generalist pinfish Lagodon rhomboides . When presented small (2 mm) bite-size pieces of whole sponge tissue, similar in size to what fish might incidentally ingest should they attempt to consume sponge-mesofaunal associates, pinfish displayed strong feeding deterrence. Alginate food pellets containing tissue-level concentrations of sponge spicules caused a weak but significant deterrent response. In contrast, alginate pellets containing tissue-level concentrations of either lipophilic or hydrophilic extracts of A. viridis were highly deterrent to pinfish. Thus, chemical, and to a considerably lesser degree, physical defenses (spicules) may contribute to this sponge serving as a protective refuge for associated mesofauana.

Can seamounts provide a good habitat for polychaete annelids? Example of the northeastern Atlantic seamounts

Two seamount groups in the northeastern Atlantic were investigated during the 1980s and 1990s: the first was located along the Iberian and African coasts (Galicia, to the north of Portugal; and the Ampere, Gorringe, Josephine and Seine banks near the Madeira–Canary Islands) and the second was located offshore of the southern part of the Azores Islands, included the Atlantis, Hyeres, Irving, Meteor and Plato banks. Among the invertebrates, Annelida, specifically Polychaeta, were studied as surrogates for the biogeographical relationship between coastal and mid-oceanic seamounts in the northeastern Atlantic and the fauna in these areas. The dominant families were Onuphidae (27.46%), Syllidae (18.23%), Eunicidae (15.65%), Amphinomidae (11.45%) and Nereididae (5.61%), representing 78.4% of the total fauna. Data analyses clearly distinguished two seamount groups, one for coastal seamounts and the other offshore. Although the species distinguished and the family composition at the sampled sites were different (i.e., most diversified at the Josephine site and most impoverished at the Irving site), no coastal/offshore faunal impoverishment gradient could be identified. Thus, it seems that seamount environments do not favour any relationship between planktotrophic development and the direct development of polychaetes. Though the number of apparent endemic species was low (<7%), it remained in keeping with other invertebrate groups. Still, while seamounts may well encourage oceanic biodiversity in some zoological groups, this was clearly not the case for the polychaetes. We offer two explanations for this paradox: pelagic productivity and local environmental conditions.

A standardized sampling method to estimate mosquito richness and abundance for research and public health surveillance programmes

Programmes involving mosquito research and surveillance are normally focused on the study of aquatic larval stages, but sampling methods are varied and not systematized, which hinders the comparative analysis of ecological data. A standardized method for assessing the richness and abundance of mosquito larval populations of value for the analysis of mosquito diversity is presented. Based on the study of all the aquatic sites in a one hectare sample area with a proportional number of dips according to the size of the aquatic habitat, comparative data can be obtained on species richness and relative abundance of species found between pairs of sites or in the same area at different times. This technique provides information on the total mosquito fauna at each site, helps recognize species of medical importance and estimates the abundance of each species; parameters that are not estimated by the current entomological indexes used in surveillance programmes. The quality of the inventory is obtained by estimation of the efficiency effort. Procedures for calculating alpha, beta and gamma diversity are presented. The technique was validated in a natural and an urban zone at La Mancha, Veracruz, Mexico, over two years of sampling made during different climatic seasons.

Redefining the trophic importance of seagrasses for fauna in tropical Indo-Pacific meadows

Abstract Fauna species living in seagrass meadows depend on different food sources, with seagrasses often being marginally important for higher trophic levels. To determine the food web of a mixed-species tropical seagrass meadow in Sulawesi, Indonesia, we analyzed the stable isotope (δ13C and δ15N) signatures of primary producers, particulate organic matter (POM) and fauna species. In addition invertebrates, both infauna and macrobenthic, and fish densities were examined to identify the important species in the meadow. The aims of this study were to identify the main food sources of fauna species by comparing isotopic signatures of different primary producers and fauna, and to estimate qualitatively the importance of seagrass material in the food web. Phytoplankton and water column POM were the most depleted primary food sources for δ13C (range −23.1 to −19.6‰), but no fauna species depended only on these sources for carbon. Epiphytes and Sargassum sp. had intermediate δ13C values (−14.2 to −11.9‰). Sea urchins, gastropods and certain fish species were the main species assimilating this material. Seagrasses and sedimentary POM had the least depleted values (−11.5 to −5.7‰). Between the five seagrass species significant differences in δ13C were measured. The small species Halophila ovalis and Halodule uninervis were most depleted, the largest species Enhalus acoroides was least depleted, while Thalassia hemprichii and Cymodocea rotundata had intermediate values. Fourteen fauna species, accounting for ∼10% of the total fauna density, were shown to assimilate predominantly (>50%) seagrass material, either directly or indirectly by feeding on seagrass consumers. These species ranged from amphipods up to the benthic top predator Taeniura lymma. Besides these species, about half of the 55 fauna species analyzed had δ13C values higher than the least depleted non-seagrass source, indicating they depended at least partly for their food on seagrass material. This study shows that seagrass material is consumed by a large number of fauna species and is important for a large portion of the food web in tropical seagrass meadows.

Distribution and diversity of sipunculan fauna in high Arctic fjords (west Svalbard)

Sipuncula is a relatively species poor and generally rarely investigated phylum; nonetheless, it may play a considerable role in the ecosystem. During this study sipunculan species distribution patterns in four fjords of west Spitsbergen (Kongsfjorden, Hornsund, Isfjorden and van Mijenfjorden) were examined. Material was collected during ten cruises undertaken from 1997 to 2006. A total of 381 samples were taken at 132 stations located in the four fjords and, a total number of 920 sipunculans specimens were found in 114 of those samples. The highest sipunculan species richness was observed in Hornsund (six species), followed by Kongsfjorden and Isfjorden (Wve species in each fjord). Sipunculan fauna in all fjords was strongly dominated by GolWngia vulgaris (80% of all sipunculan individuals in Kongsfjorden), and GolWngia margaritacea (84% in van Mijenfjorden and 40% in Hornsund) or Nepha- soma diaphanes (54% in Isfjorden). Locally, sipunculans were found in high densities (max. 62 ind. 0.1 m i2 and up to 11% of macrobenthic densities) and biomass (max. 110.87 g 0.1 m i2 and up to 80% of total fauna biomass). At such sites, sipunculans may play an important role in bioturbation of sediments and as a food source for higher trophic levels. Sipunculans did not occur within close proximity of the gla- cier where they might be eliminated due to high sedimenta- tion rate and low amounts of organic matter. Because of their importance in benthic systems, a need to include sipunculans in routine macrobenthic surveys is emphasized.

Investigator Group Expedition 2006: Vertebrate Fauna

The vertebrate fauna of the Investigator Group includes 11 native (five now extinct) and four introduced mammals, 63 native and four introduced birds and 20 native reptiles. The determination of the total mammal fauna of Flinders Island was based on sub-fossil bone collections. The extinction of the Flinders Island form of the Tammar Wallaby between 1968 and 1974 is described. Australian Sea-lion and New Zealand Fur-seal breeding colonies and haul out sites on all the islands are documented. Sea-lion pup numbers on Ward Island greatly exceeded any previous reports.

Late Quaternary radiolarian assemblages as indicators of paleoceaonographic changes north of the subtropical front, offshore eastern New Zealand, southwest Pacific

Abundant and diverse polycystine radiolarian faunas from ODP Leg 181, Site 1123 (0-1.2 Ma at ~21 kyr resolution) and Site 1124 (0-0.6 Ma, ~5 kyr resolution, with a disconformity between 0.42-0.22 Ma) have been used to infer Pleistocene-Holocene paleoceanographic changes north of the Subtropical Front (STF), offshore eastern New Zealand, southwest Pacifi c. The abundance of warm-water taxa relative to cool-water taxa was used to determine a radiolarian paleotemperature index, the Subtropical (ST) Index. ST Index variations show strong covariance with benthic foraminifera oxygen isotope records from Site 1123 and exhibit similar patterns through Glacial-Interglacial (G-I) cycles of marine isotope stages (MIS)15-1. At Site 1123, warm-water taxa peak in abundance during Interglacials (reaching ~8% of the total fauna). Within Glacials cool-water taxa increase to ~15% (MIS2) of the fauna. Changes in radiolarian assemblages at Site 1124 indicate similar but much better resolved trends through MIS15-12 and 7-1. Pronounced increases in warm-water taxa occur at the onset of Interglacials (reaching ~15% of the fauna), whereas the abundance of cool-water taxa increases in Glacials peaking in MIS2 (~17% of the fauna). Overall warmer conditions at Site 1124 during the last 600 kyrs indicate sustained infl uence of the subtropical, warm East Cape Current (ECC). During Interglacials radiolarian assemblages suggest an increase in marine productivity at both sites which might be due to predominance of micronutrient-rich Subtropical Water. At Site 1123, an increased abundance of deep-dwelling taxa in MIS 13 and 9 suggests enhanced vertical mixing. During Glacials, reduced vigour of ECC fl ow combined with northward expansion of cool, micronutrient-poor Subantarctic Water occurs. Only at Site 1123 there is evidence of a longitudinal shift of the STF, reaching as far north as 41°S.

Caddisfly (Trichoptera) larvae of the Opa River basin, south-western Nigeria

Caddisflies in the streams of the Opa River catchment basin in Ile-Ife, south-western Nigeria, were surveyed, documenting nine genera in six families. Hydropsychidae is the most speciose family, with three genera, and has the highest number of individuals in the total fauna. Streams in the area with appreciable disturbance were devoid of caddisflies. This was attributed to the impact of human activities although other factors such as substrate availability and stream size could also apply. The large number of hydropsychid caddisflies at one sampling station was attributed to the presence of submerged beds of Fontinalis (Bryophyta) in that area, which is usually associated with the occurrence of that taxon. Efforts should be made to create favourable conditions in the streams and rivers of this catchment to avoid possible extermination of caddisflies and to foster an increase in species richness.

The Pennsylvanian (Moscovian) Izvarino Section, Donets Basin, Ukraine: A Multidisciplinary Study on Microfacies, Biostratigraphy (Conodonts, Foraminifers, and Ostracodes), and Paleoecology

The mid-Moscovian Izvarino section, Donets Basin, eastern Ukraine, exhibits a complete sedimentological record of siliciclastics (sandstones, siltstones, and calcareous shales) with limestone intercalations and, rarely, coal seams. A multidisciplinary study including microfacies analysis, systematic paleontology (conodonts, fusulinoideans, and ostracodes), biostratigraphy, and paleoecology was focused on the limestones, from limestone L4through limestone M1, and the adjacent marine shales. Based on sedimentology and fossil associations, the cyclic sediments of the Izvarino section were interpreted as entirely marine deposits of open- and shallow-marine, nearshore and offshore environments with variable terrigenous input.The well-preserved ostracode faunas are dominated by representatives of the families Amphissitidae, Hollinellidae, Healdiidae, Cavellinidae, and Paraparchitidae. The total fauna is 18 species, of which four are new:Hollinella (Hollinella) granulobaFohrer, n. sp.,Hollinella(Praehollinella)kamenkaFohrer, n. sp.,Jordanites krasnodonensisFohrer, n. sp., andAsturiella donbassicaFohrer, n. sp. The conodont fauna includes 21 species belonging to nine genera and includes one new species:Idiognathodus izvaricusNemyrovska, n. sp. The conodont faunas are dominated by idiognathodontids. Representatives ofDiplognathodusandNeognathodusplay a subordinate role. A total of 56 fusulinoidean species referable to 20 genera has been identified; one is new:Eostaffella brazhnikovaeUeno, n. sp.Conodont and fusulinoidean biostratigraphy led to surprising differences in the age assignment of the Izvarino section and its correlation with the nearby Moscow Basin, Russia. The interval studied is lower Kashirian (Tsninskaya) to middle Kashirian (Narskaya), according to conodonts. It extends to the base of the Podolskian, however, according to fusulinoideans. This discrepancy is possibly related to problems in correlation of the type sections in the Moscow Basin. It calls for reexamination of the mid-Moscovian boundary interval and shows the limits of interbasinal correlations based on a single fossil group.

An Analysis of the History of Marine Animal Diversity

Abstract According to when they attained high diversity, major taxa of marine animals have been clustered into three groups, the Cambrian, Paleozoic, and Modern Faunas. Because the Cambrian Fauna was a relatively minor component of the total fauna after mid-Ordovician time, the Phanerozoic history of marine animal diversity is largely a matter of the fates of the Paleozoic and Modern Faunas. The fact that most late Cenozoic genera belong to taxa that have been radiating for tens of millions of years indicates that the post-Paleozoic increase in diversity indicated by fossil data is real, rather than an artifact of improvement of the fossil record toward the present. Assuming that ecological crowding produced the so-called Paleozoic plateau for family diversity, various workers have used the logistic equation of ecology to model marine animal diversification as damped exponential increase. Several lines of evidence indicate that this procedure is inappropriate. A plot of the diversity of marine animal gene...

Species richness and complementarity of beetle faunas in a mediterranean-type biodiversity hotspot

Regions of mediterranean-type climate represent most extra-tropical biodi- versity hotspots, being both highly diverse and highly endangered. Though renowned for their plant richness, these regions' insects constitute the bulk of their alpha diversities. Data on insect distribution and rarity are generally lacking for such regions, and are often considered unattainable. Intensive field inventories combined with statistical extrapolation methods can provide a sufficient understanding of alpha, beta, and gamma diversity components for application to conservation planning. These are essential to assessing the adequacy of a regional reserve network for the conservation of insect diversity. Here the beetle faunas of three protected areas spanning three major ecoregions in the California Floristic Province were inventoried and analyzed for species richness, complementarity, and uniqueness. These surveys produced collectively nearly 1,200 species from all three sites, estimated to be about 80% of their total faunas. Diversity was highly partitioned among sites, no one site containing more than 60% of the species. Dissimilarity was moderate to high for all comparisons, and all sites contained >40% unique species. Comparison of these results with those based on species of co-occurring plants reveal incongruent species richness but congruent similarities among sites. These results provide quantitative support to the perception that mediterranean insect faunas show high spatial variability. Along with online specimen level data on distribution, rarity, and seasonality, these results will help speed the incorporation of insect data into serious conservation planning.

Spatial and temporal changes in interstitial meiofauna on a sandy ocean beach of South America

Spatial and temporal patterns of meiofauna community from a Brazilian sandy beach were investigated. The objective of this work was to analyze the meiofauna distribution using a statistical model that considers the biological data as variables, and granulometric characteristics, organic matter, and temperature as covariables.Four zones were sampled throughout one year in a Brazilian sandy beach and three sediment cores were taken monthly from each zone. The meiofauna was composed by 12 taxa, with tardigrades and nematodes comprising 92% of the total fauna. The meiofauna mean density varied from 1556.25 to 13125.25 ind.10 cm-2, with the highest densities in December. The results of multiple regression showed that the mean effects of zones, vertical layers, and months on the organisms were significantly correlated with the principal taxa of meiofauna. The retention zone and the 0-10 cm layer presented the highest densities. The temporal distribution showed different patterns and some taxa were more abundant in the dry season, and others in the rainy season. Sedimentological variables had strong and significant effects on the meiofauna taxa. According to the results, physical variables at the retention zone create optimal living conditions for the meiobentos, making this zone an area that favors the basic and applied ecological studies.

Postinoculation Protozoan Establishment and Association Patterns of Methanogenic Archaea in the Ovine Rumen

Association patterns between archaea and rumen protozoa were evaluated by analyzing archaeal 16S rRNA gene clone libraries from ovine rumen inoculated with different protozoa. Five protozoan inoculation treatments, fauna free (negative control), holotrich and cellulolytic protozoa, Isotricha and Dasytricha spp., Entodinium spp., and total fauna (type A) were tested. We used denaturing gradient gel electrophoresis, quantitative PCR, and phylogenetic analysis to evaluate the impact of the protozoan inoculants on the respective archaeal communities. Protozoan 18S ribosomal DNA clone libraries were also evaluated to monitor the protozoal population that was established by the inoculation. Phylogenetic analysis suggested that archaeal clones associated with the fauna-free, the Entodinium, and the type A inoculations clustered primarily with uncultured phylotypes. Polyplastron multivesiculatum was the predominant protozoan strain established by the holotrich and cellulolytic protozoan treatment, and this resulted predominantly in archaeal clones affiliated with uncultured and cultured methanogenic phylotypes (Methanosphaera stadtmanae, Methanobrevibacter ruminantium, and Methanobacterium bryantii). Furthermore, the Isotricha and Dasytricha inoculation treatment resulted primarily in archaeal clones affiliated with Methanobrevibacter smithii. This report provides the first assessment of the influence of protozoa on archaea within the rumen microbial community and provides evidence to suggest that different archaeal phylotypes associate with specific groups of protozoa. The observed patterns may be linked to the evolution of commensal and symbiotic relationships between archaea and protozoa in the ovine rumen environment. This report further underscores the prevalence and potential importance of a rather large group of uncultivated archaea in the ovine rumen, probably unrelated to known methanogens and undocumented in the bovine rumen.

Memoir 4: An Analysis of the History of Marine Animal Diversity

According to when they attained high diversity, major taxa of marine animals have been clustered into three groups, the Cambrian, Paleozoic, and Modern Faunas. Because the Cambrian Fauna was a relatively minor component of the total fauna after mid-Ordovician time, the Phanerozoic history of marine animal diversity is largely a matter of the fates of the Paleozoic and Modern Faunas. The fact that most late Cenozoic genera belong to taxa that have been radiating for tens of millions of years indicates that the post-Paleozoic increase in diversity indicated by fossil data is real, rather than an artifact of improvement of the fossil record toward the present.Assuming that ecological crowding produced the so-called Paleozoic plateau for family diversity, various workers have used the logistic equation of ecology to model marine animal diversification as damped exponential increase. Several lines of evidence indicate that this procedure is inappropriate. A plot of the diversity of marine animal genera through time provides better resolution than the plot for families and has a more jagged appearance. Generic diversity generally increased rapidly during the Paleozoic, except when set back by pulses of mass extinction. In fact, an analysis of the history of the Paleozoic Fauna during the Paleozoic Era reveals no general correlation between rate of increase for this fauna and total marine animal diversity. Furthermore, realistically scaled logistic simulations do not mimic the empirical pattern. In addition, it is difficult to imagine how some fixed limit for diversity could have persisted throughout the Paleozoic Era, when the ecological structure of the marine ecosystem was constantly changing. More fundamentally, the basic idea that competition can set a limit for marine animal diversity is incompatible with basic tenets of marine ecology: predation, disturbance, and vagaries of recruitment determine local population sizes for most marine species. Sparseness of predators probably played a larger role than weak competition in elevating rates of diversification during the initial (Ordovician) radiation of marine animals and during recoveries from mass extinctions. A plot of diversification against total diversity for these intervals yields a band of points above the one representing background intervals, and yet this band also displays no significant trend (if the two earliest intervals of the initial Ordovician are excluded as times of exceptional evolutionary innovation). Thus, a distinctive structure characterized the marine ecosystem during intervals of evolutionary radiation—one in which rates of diversification were exceptionally high and yet increases in diversity did not depress rates of diversification.Particular marine taxa exhibit background rates of origination and extinction that rank similarly when compared with those of other taxa. Rates are correlated in this way because certain heritable traits influence probability of speciation and probability of extinction in similar ways. Background rates of origination and extinction were depressed during the late Paleozoic ice age for all major marine invertebrate taxa, but remained correlated. Also, taxa with relatively high background rates of extinction experienced exceptionally heavy losses during biotic crises because background rates of extinction were intensified in a multiplicative manner; decimation of a large group of taxa of this kind in the two Permian mass extinctions established their collective identity as the Paleozoic Fauna.Characteristic rates of origination and extinction for major taxa persisted from Paleozoic into post-Paleozoic time. Because of the causal linkage between rates of origination and extinction, pulses of extinction tended to drag down overall rates of origination as well as overall rates of extinction by preferentially eliminating higher taxa having relatively high background rates of extinction. This extinction/origination ratchet depressed turnover rates for the residual Paleozoic Fauna during the Mesozoic Era. A decline of this fauna's extinction rate to approximately that of the Modern Fauna accounts for the nearly equal fractional losses experienced by the two faunas in the terminal Cretaceous mass extinction.Viewed arithmetically, the fossil record indicates slow diversification for the Modern Fauna during Paleozoic time, followed by much more rapid expansion during Mesozoic and Cenozoic time. When viewed more appropriately as depicting geometric—or exponential—increase, however, the empirical pattern exhibits no fundamental secular change: the background rate of increase for the Modern Fauna—the fauna that dominated post-Paleozoic marine diversity—simply persisted, reflecting the intrinsic origination and extinction rates of constituent taxa. Persistence of this overall background rate supports other evidence that the empirical record of diversification for marine animal life since Paleozoic time represents actual exponential increase. This enduring rate makes it unnecessary to invoke environmental change to explain the post-Paleozoic increase of marine diversity.Because of the resilience of intrinsic rates, an empirically based simulation that entails intervals of exponential increase for the Paleozoic and Modern Faunas, punctuated by mass extinctions, yields a pattern that is remarkably similar to the empirical pattern. It follows that marine animal genera and species will continue to diversify exponentially long into the future, barring disruption of the marine ecosystem by human-induced or natural environmental changes.

Long-term dynamics (1990 to 2004) of the polychaete fauna from the sublittoral soft-bottoms off Punta Coloso (Antofagasta), northern Chile

Long-term monitoring (1990 to 2004) at four stations (50 to 60 m depth) off Punta Coloso, Antofagasta, northern Chile, has allowed us to study temporal changes in the sublittoral macrobenthic polychaete infauna composition and abundance. The numerical contribution of the polychaete fraction to the total fauna was high (65 to 93%), whereas biomass was smaller and variable (20 to 85%). The number of invertebrate species collected per cruise was relatively low (40 to 90 species) and the number of polychaete species ranged from 18 to 37 per cruise (mean = 29.9), with a cumulative number of 56 polychaete species. The most abundant species collected included the small-sized Aricidea pigmentata Carrasco (26.5%), Magelona phyllisae Jones (22.7%), Paraprionospio pinnata (Ehlers) (13.5%), Tharyx longisetosa Hartmann-Schroder (12.1%), and Prionospio peruana Hartmann-Schroder (11.8%). Clear general patterns or tendencies are not seen in temporal variations of polychaete fauna nor when analyzing the seasons individually. P. pinnata was the only dominant species to show a general tendency in abundance fluctuations. Although the study period included two El Nino events (1991-1992 and 1997-1998), a clear dynamic was not seen in either abundance or dominant species. The analyzed data validate or corroborate high stability or persistence over time that has been suggested for polychaete fauna in the study area. Such stability or persistence exists in spite of high seasonal variability and interannual fluctuations in the region’s oceanographic conditions.

Habitat preferences and seasonal activity of the Microstigmatidae from Ngome State Forest, South Africa (Arachnida: Araneae)

As part of the South African National Survey of Arachnida (SANSA) inventories are underway to determine the arachnid biodiversity of various biomes. Asurvey of groundliving spiders was conducted over a year period (1992-1993) at Ngome State Forest, KwaZulu-Natal, South Africa. Spiders were collected with 180 pitfall traps from five different habitat types ranging from indigenous forest to a pine plantation and grassland. A total of 186 specimens of the rare Mygalomorphae family Microstigmatidae were sampled, representing 2 % of the total spider fauna collected during the study. Two species, Microstigmata longipes (Lawrence) and M. zuluensis (Lawrence), occur sympatrically. Both species were more active in the indigenous forest, and were absent or present in low numbers in the open grass and pine plantation. Microstigmata zuluensis was slightly more abundant (59 % of total) and was recorded from three of the five habitats, while M. longipes (41 %) was found in four of the habitat types. Both species were active throughout the year with the lowest numbers recorded in winter (June to August). The males of M. longipes peaked in November while those of M. zuluensis peaked in April.