Chilean Darwin Wasps (Ichneumonidae): Biogeographic Relationships and Distribution Patterns

Ichneumonidae, or Chilean Darwin wasps, are an important component of South American hymenopteran diversity, but the taxonomic and distributional knowledge on this insect is still deficient. Taking advantage of recently updated taxonomic knowledge, we assessed biogeographic relationships at the genus level and biodiversity spatial patterns along the latitudinal gradient. The results show the presence of 264 species in Chile, arranged in 102 genera and 22 subfamilies. Biogeographic relationships are based on six elements (cosmopolitan (n = 50; 36%), endemic (n = 29; 21%), Neotropical (n = 22; 16%), Holarctic-Oriental (n = 19; 14%), south-temperate (n = 16; 11%) and Australasian) and composed of just three genera: Anacis, Labena, and Meringops. Species and genera show a bimodal distribution along the latitudinal gradient: around 34° and 38° S. From an ecoregional perspective, richness is concentrated in the Valdivian temperate forests, but when assessed at a 0.5 × 0.5 cell scale, several outstanding cells are in the contact zone between the temperate forests and the Chilean Matorral. On the other hand, the Atacama Desert shows little or no presence of Darwin wasps. The results agree with Charles Porter, who identified a northern province composed of Neotropical and cosmopolitan genera with their own representatives in the far north (11 genera), a distributional gap in the core of the Atacama Desert, and around 128 genera in Porter's Neantarctic realm, covering all of Chile from 25° S to Cape Horn, including the Juan Fernandez islands. These results reinforce knowledge gaps and the need for more sampling and studies of available collections. Due to sampling gaps at this stage, identifying a continued increase or decrease in richness towards higher latitudes is not possible. More taxonomic and distributional information is also needed to assess potential threats to endemic genera and species.

The distribution of biodiversity richness in the tropics

We compare the numbers of vascular plant species in the three major tropical areas. The Afrotropical Region (Africa south of the Sahara Desert plus Madagascar), roughly equal in size to the Latin American Region (Mexico southward), has only 56,451 recorded species (about 170 being added annually), as compared with 118,308 recorded species (about 750 being added annually) in Latin America. Southeast Asia, only a quarter the size of the other two tropical areas, has approximately 50,000 recorded species, with an average of 364 being added annually. Thus, Tropical Asia is likely to be proportionately richest in plant diversity, and for biodiversity in general, for its size. In the animal groups we reviewed, the patterns of species diversity were mostly similar except for mammals and butterflies. Judged from these relationships, Latin America may be home to at least a third of global biodiversity.

Barsine podbolotskayae sp. n. from Flores Island, Lesser Sunda Archipelago, Indonesia (Lepidoptera, Erebidae, Arctiinae)

Herein Barsinepodbolotskayaesp. n. (Lepidoptera: Erebidae: Arctiinae) is described from Flores Island, Lesser Sunda Archipelago, Indonesia. This local endemic species externally resembles Barsineexclusa Butler, 1877 from Sundaland and the Andaman Islands but differs by marking patterns and male genitalia structure.

The ant fauna of Timor and neighbouring islands: potential bridges between the disjunct faunas of South East Asia and Australia

This study examines the biogeography of the ant fauna of Timor and of stepping stone Nusa Tenggara islands to the north (Wetar, Atauro, Alor, Pantar and Lembata) that are geographically closer to continental South East Asia. Timor is of outstanding biogeographical significance because it is the second largest island within the Wallacean transitional zone between the closely approximated but geologically distinct Indo-Australasian and South East Asian continental plates. It represents a potential overlap zone between the otherwise disjunct ant faunas of Australia and South East Asia. A total of 154 ant species from 32 genera and six subfamilies were collected through a combination of systematic sampling in evergreen forest, dry forest, savanna and grassland at 23 locations in the Lautem district of Timor-Leste, and opportunistic collections at 29 sites elsewhere on Timor and on the neighbouring islands. The most species-rich genera were Camponotus and Polyrhachis (both 28 species), Tetramorium (14 species), Diacamma and Paratrechina (both 8 species). On Timor, 111 ant species were recorded, including 64 species in the Lautem district. The Timor ant fauna is dominated by taxa of South East Asian origin (76% of native species), and has only weak Australian affinities (18%). The latter figure is even smaller (14%) for the neighbouring islands, reflecting their closer proximity to South East Asia. In contrast to Australia, there was no clear disjunction between the ant faunas of contrasting tropical forest and savanna habitats sampled in Lautem district. This can be explained by the Timor ant fauna being dominated by South East Asian tropical forest taxa, with Australian savanna woodland taxa being poorly represented.

When and where did troidine butterflies (Lepidoptera : Papilionidae) evolve? Phylogenetic and biogeographic evidence suggests an origin in remnant Gondwana in the Late Cretaceous

The age, geographic origin and time of major radiation of the butterflies (Hesperioidea + Papilionoidea + Hedyloidea) are largely unknown. The general modern view is that butterflies arose during the Late Jurassic/Cretaceous in the southern hemisphere (southern Pangea/Gondwana before continental breakup), but this is not universally accepted, and is a best guess based largely on circumstantial evidence. The extreme paucity of fossils and lack of modern, higher-level phylogenies of extant monophyletic groups have been major impediments towards determining reliable estimates of either their age or geographic origin. Here we present a phylogenetic and historical biogeographic analysis of a higher butterfly taxon, the swallowtail tribe Troidini. We analysed molecular data for three protein-encoding genes, mitochondrial ND5 and COI–COII, and nuclear EF–1α, both separately and in combination using maximum parsimony (with and without character weighting and transition/transversion weighting), maximum likelihood and Bayesian methods. Our sample included representatives of all 10 genera of Troidini and distant ingroup taxa (Baroniinae, Parnassiinae, Graphiini, Papilionini), with Pieridae as outgroup. Analysis of the combined dataset (4326 bp; 1012 parsimony informative characters) recovered the Troidini as a well supported monophyletic group and the monophyly of its two subtribes, Battina and Troidina. The most parsimonious biogeographic hypothesis suggests a southern origin of the tribe in remnant Gondwana (Madagascar–Greater India–Australia–Antarctica–South America) sometime after the rifting and final separation of Africa in the Late Cretaceous (<90 Mya). Although an ancient vicariance pattern is proposed, at least four relatively recent dispersal/extinction events are needed to reconcile anomalies in distribution, most of which can be explained by geological and climatic events in South-east Asia and Australia during the late Tertiary. Application of a molecular clock based on a rate smoothing programme to estimate various divergence times based on vicariance events, revealed two peculiarities in our biogeographic vicariance model that do not strictly accord with current understanding of the temporal breakup of Gondwana: (1) the troidine fauna of Greater India did not become isolated from Gondwana (Antarctica) until the end of the Cretaceous (c. 65 Mya), well after Madagascar separated from Greater India (84 Mya); and (2) the faunas of Greater India, Australia and South America diverged simultaneously, also at the K/T boundary. A recent published estimate of the time (31 Mya) of divergence between Cressida Swainson (Australia) and Euryades Felder & Felder (South America) is shown to be in error.

Diversity and distribution of ferns in sub-Saharan Africa, Madagascar and some islands of the South Atlantic

Aim  This paper reports the diversity and endemism patterns of African ferns, and explores the potential role of diversity refuges and environmental and historical factors in the shaping of these patterns. Material and locations  The extant fern taxa occupying Africa south of the Sahara, Madagascar and some islands of the South Atlantic. Methods  The number of taxa in each area or operational geographical unit (OGU) was scored, and the correlation between this number and physical and climatic variables analysed by standard pairwise and stepwise multiple regression analysis (SPR and SMR). The effects of biological factors such as dispersal capacity, reproductive biology, genetic features and certain physiological adaptations were evaluated by comparing the number of species in each OGU. Floral affinities among OGUs were analysed using non-metric multi-dimensional scaling (NMS) and parsimonic analysis of dispersion (PAD), and compared with β-turnover and inter-OGU distances. Results  OGU area, elevation and the distance between refuges determined the composition of local floras, but only greater OGU area and the existence of higher maximum elevations increased species richness. The distance between refuges also affected the number of endemic species, especially on islands. The biological features studied only slightly influenced fern distribution. The main climatic predictor of species number was humidity. SPR and SMR revealed three main groups of ferns with different ecological trends. NMS and PAD analyses separated the four areas of highest diversity in Africa, three of which are inhabited by ferns with distinct ecological requirements. The fourth area was Madagascar, which shows an accumulation of endemic and relict diversity that is not easy to explain. Main conclusions  The distribution of ferns in Africa has been influenced by refuges. These probably allowed many species to recolonize the neighbouring areas after the extinctions of the Pleistocene. Three major components were detected in the African flora: Guinea-Congolian thermophilous, cold-tolerant Afro-montane, and Southern drought-tolerant elements. These are related to the three main refuge areas, i.e. the Gulf of Guinea area, the eastern tropical region, and the Cape region. Endemicity in ferns was found to be lower than that of seed plants due to the higher dispersability of fern spores. The distance between OGUs seems to be the main predictor of the number of endemic fern species these areas contain.

Ordovician geography and faunal provinces deduced from trilobite distribution

Lists of families and genera of trilobites from the stratigraphical series of the Ordovician have been compiled, using information considered adequate from various areas in the world. Dissimilarities between these faunas have been assessed at both generic and family level, using Simpson’s index. These indices have been analysed by a non-metric multidimensional scaling technique, and the groupings revealed are interpreted as indicating faunal provinces. Four provinces are recognized in the Lower Ordovician, the faunal characteristics and geographical extent of three of them (the Bathyurid, Asaphid and Selenopeltis provinces) being as previously described. A fourth province, here named the Asaphopsis province, is proposed for South American and Australian faunas in the Arenig and Llanvirn; the affinities of faunas from southeast Asia are indeterminate. In the Caradoc, faunas from areas occupied earlier by Bathyurid, Asaphid and Asaphopsis faunas, together with trilobites from south-east Asia, constitute a single province, here named the Remopleuridid. The Selenopeltis province persists in southern Europe and North Africa. These two provinces are recognizable only by a generic analysis in the Ashgill, and the latest faunas of that series are world-wide. It is assumed that a faunal province originally extended over parts of a single continental mass (cf. Wilson 1966), and that migration between provinces is inhibited by width of seas or temperature differences. An assemblage of continental masses consistent with these assumptions, and with palaeomagnetic data, is proposed to give four palaeogeographical maps for the Ordovician period. The position of the proto-Atlantic ocean proposed by Wilson (1966), and Gondwanaland of McElhinney & Luck (1970), are accepted; the remainder of Eurasia is divided into four blocks. The maps suggest relative movements between continental blocks that may have removed barriers to migration and resulted in progressive merging of the faunal provinces. They are models to be tested against distributions of other animal groups, new palaeomagnetic and palaeoclimatic evidence, and theories on lithosphere plates. The geographical reconstructions imply that the faunas of South America, southern Europe and North Africa inhabited cool waters, those of North America, northern Europe, north-east Asia, south-east Asia and Australia, warm waters. Cooler water faunas appear to have been less diverse. Decreasing provinciality of faunas during the Ordovician appears to have been accompanied by a reduction in total diversity; supposed climatic deterioration does not seem to have resulted in increased diversity. The differences between contemporaneous faunas within the Bathyurid and Remopleuridid provinces are investigated, and are shown to reflect differences in environment and evolution and diversification of groups of trilobites which took place in these environments.

Selecting indicator taxa for the quantitative assessment of biodiversity

Introducing greater objectivity to selection of indicator taxa produces results that are likely to reduce uncertainty, be more efficiently obtained and more clearly communicated. Seven criteria are presented that can be used to objectively test the claim that a given taxon is an ideal indicator: (i) well known and stable taxonomy; (ii) well known natural history; (iii) readily surveyed and manipulated; (iv) higher taxa broadly distributed geographically and over a breadth of habitat types; (v) lower taxa specialized and sensitive to habitat changes; (vi) patterns of biodiversity reflected in other related and unrelated taxa; and (vii) potential economic importance. These criteria have different priorities depending on which of two general categories of biodiversity the indicator taxon is to be used. Monitoring places an emphasis on sensitivity to habitat change, and inventory places an emphasis on systematics. An index is suggested by which the results of selecting an indicator taxon can be more accurately communicated. This index is based on the number of criteria that are successfully tested for the proposed indicator and their priority.