We analysed patterns of animal dispersal, vicariance and diversification in the Holarctic based on complete phylogenies of 57 extant non-marine taxa, together comprising 770 species, documenting biogeographic events from the Late Mesozoic to the present. Four major areas, each corresponding to a historically persistent landmass, were used in the analyses: eastern Nearctic (EN), western Nearctic (WN), eastern Palaeoarctic (EP) and western Palaeoarctic (WP). Parsimony-based tree fitting showed that there is no significantly supported general area cladogram for the dataset. Yet, distributions are strongly phylogenetically conserved, as revealed by dispersalvicariance analysis (DIVA). DIVA-based permutation tests were used to pinpoint phylogenetically determined biogeographic patterns. Consistent with expectations, continental dispersals (WP-EP and WN-EN) are significantly more common than palaeocontinental dispersals (WN-EP and EN-WP), which in turn are more common than disjunct dispersals (EN-EP and WN-WP). There is significant dispersal asymmetry both within the Nearctic (WN+EN more common than EN+WN) and the Palaeoarctic (EP+WP more common than WP-tEP). Cross-Beringian faunal connections have traditionally been emphasized but are not more important than cross-Atlantic connections in our data set. To analyse changes over time, we sorted biogeographic events into four major time periods using fossil, biogeographic and molecular evidence combined with a 'branching clock. These analyses show that trans-Atlantic distributions (EN-WP) were common in the Early-Mid Tertiary (70-20 Myr), whereas trans-Beringian distributions (WN-EP) were rare in that period. Most EN-EP disjunctions date back to the Early Tertiary (7045 Myr), suggesting that they resulted from division of cross-Atlantic rather than cross-Beringian distributions. Diversification in WN and W P increased in the Quaternary (< 3 Myr), whereas in E P and EN it decreased from a maximum in the Early-Mid Tertiary. 0 2001 The Linnean Society of London ADDITIONAL KEY WORDS: historical biogeographytrans-Atlantictrans-Beringiandisjunct.This incongruence is measured in abstract terms, such as items of error or amount of homoplasy. The incongruence can then be interpreted a posteriori in terms of biogeographic events, such as dispersal and extinction. The exact procedure for this a posteriori translation remains elusive. Furthermore, because no model is specified, it is difficult to predict the analytical behaviour of pattern-based methods and counter-intuitive results often occur (e.g. Ronquist, 1995Ronquist, , 1996.In contrast, event-based methods are explicitly derived from models of biogeographic processes. The relevant events are identified and associated with costs that are inversely related to the likelihood of t h e events. The analysis consists of a search for the reconstruction, which minimizes the total cost. This optimal reconstruction explicitly specifies the biogeographic events of interest, unlike pattern-based

A review of the postembryonic development of millipedes (Diplopoda) is given, based mainly on published information. Original observations are, however, also included. Millipedes hatching from the pupoid usually have three pairs of legs; during their postembryonic growth they acquire more segments and more legs. This process is known as anamorphosis. Three types of anamorphosis are recognized. In euanamorphosis, every moult is accompanied by addition of new segments, even after the attainment of sexual maturity. In hemianamorphosis, the addition of new segments goes on until a certain stadium, and further moults take place without addition of segments. In teloanamorphosis, the addition of segments stops at a certain stadium (the adult, and ultimate, stadium) after which no further moults occur. Available information on anamorphosis in each of the millipede orders is reviewed. General patterns are emphasized, but variations are also considered in detail. It is shown that the so‐called ‘law of anamorphosis’ is valid only for the ‘ring‐forming’ millipedes (Merocheta and Juliformia) in which tergites, pleurites, and sternites of each diplosegment are firmly fused into a complete ‘ring’, and for some other forms (Polyzoniida, Chordeumatida), where there is a constant relationship between rings and legs. The chapter on the order Julida is particularly detailed and includes discussions of patterns in the variation and a section on periodomorphosis. The general chapter on developmental patterns includes inter alia an interpretation of the variations in millipede anamorphosis in terms of the ‘biometabolic modi’ of Remane. The hypothetical ancestral millipede is shown to have developed by hemianamorphosis. Euanamorphosis was acquired by the ancestral species of Helminthomorpha. Within this clade, Chordeumatida and Merocheta have secondarily become teloanamorphic, whereas some Juliformia seem to have returned to hemianamorphosis. The contrasting principles of elongation and contraction, subject of much debate among diplopodologists, are shown both to have played a role in the course of millipede evolution.

Abstract. Nineteen areas in seven of the nine Azorean islands were evaluated for species diversity and rarity based on soil epigean arthropods. Fifteen out of the 19 study areas are managed as Natural Forest Reserves and the remaining four were included due to their importance as indigenous forest cover. Four of the 19 areas are not included in the European Conservation network, NATURA 2000. Two sampling replicates were run per study area, and a total of 191 species were collected; 43 of those species (23%) are endemic to the archipelago and 12 have yet to be described. To produce an unbiased multiple-criteria index (importance value for conservation, IV-C) incorporating diversity and rarity based indices, an iterative partial multiple regression analysis was performed. In addition, an irreplaceability index and the complementarity method (using both optimisation and heuristic methods) were used for priority-reserves analyses. It was concluded that at least one well-managed reserve per island is absolutely necessary to have a good fraction of the endemic arthropods preserved. We found that for presence/absence data the suboptimal complementarity algorithm provides solutions as good as the optimal algorithm. For abundance data, optimal solutions indicate that most reserves are needed if we want that at least 50% of endemic

Abstract. For each of the 593 species of the millipede order Julida known from Europe, available information on taxonomy, distribution and habitat is summarized, and the distribution in 50 × 50 km UTM squares is shown on a map.

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We review the state-of-the-art approaches currently applied in myriapod taxonomy, and we describe, for the first time, a new species of millipede (Ommatoiulus avatar n. sp., family Julidae) using high-resolution X-ray microtomography (microCT) as a substantive adjunct to traditional morphological examination. We present 3D models of the holotype and paratype specimens and discuss the potential of this non-destructive technique in documenting new species of millipedes and other organisms. The microCT data have been uploaded to an open repository (Dryad) to serve as the first actual millipede cybertypes to be published.

The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late.

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