Upon publication of this article, it was suggested that some of the entries of the two web-type matrices required revision. We have amended the web data and performed the relevant analyses in order to assess whether such changes overturn any of the web evolution inferences of the study. Seventy-nine out of a total of 1,085 entries were revised with new scores (7.28%) as follows: Twentynine of the entries were conservatively changed to ''?'' to reflect absence of published data on their webs; the remaining 50 entries correct errors or provide new web coding interpretations. State 8 in the matrix for the taxa with transcriptomes has been reworded as ''non-foraging silk-lined burrows.'' After revising the scoring for web building behavior and web architecture, we repeated the relevant comparative analyses using the same methodological approaches described in the original article to reconstruct the evolution of these traits in spiders. Analyses of both the ten-and the three-character-state datasets were carried out with R packages ape [1] and phytools [2], and both revised datasets have been deposited in the Harvard Dataverse repository (https://doi.org/10.7910/ DVN/EJOMZP). Re-analyses of the revised data do not alter our previous conclusions in any significant way. Figures 3 and S2 have been corrected in the article online, and the corrected Figures 3 and S2 are also shown below. The authors apologize to the readers for any inconvenience that this revision may have caused and thank the colleagues that kindly suggested changes.

Spiders of the recently described linyphiid genus Orsonwelles (Araneae, Linyphiidae) are one of the most conspicuous groups of terrestrial arthropods of Hawaiian native forests. There are 13 known Orsonwelles species, and all are single- island endemics. This radiation provides an excellent example of insular gigantism. We reconstructed the cladistic relationships of Orsonwelles species using a combination of morphological and molecular characters (both mitochondrial and nuclear sequences) within a parsimony framework. We explored and quantified the contribution of different character partitions and their sensitivity to changes in the traditional parameters (gap, transition, and transversion costs). The character data show a strong phylogenetic signal, robust to parameter changes. The monophyly of the genus Orsonwelles is strongly supported. The parsimony analysis of all character evidence combined recovered a clade with of all the non-Kauai Orsonwelles species; the species from Kauai form a paraphyletic assemblage with respect to the latter former clade. The biogeographic pattern of the Hawaiian Orsonwelles species is consistent with colonization by island progression, but alternative explanations for our data exist. Although the geographic origin of the radiation remains unknown, it appears that the ancestral colonizing species arrived first on Kauai (or an older island). The ambiguity in the area cladogram (i.e., post-Oahu colonization) is not derived from conflicting or unresolved phylogenetic signal among Orsonwelles species but rather from the number of taxa on the youngest islands. Speciation in Orsonwelles occurred more often within islands (8 of the 12 cladogenic events) than between islands. A molecular clock was rejected for the sequence data. Divergence times were estimated by using the nonparametric rate smoothing method of Sanderson (1997, Mol. Biol. Evol. 14:1218-1231) and the available geological data for calibration. The results suggest that the oldest divergences of Orsonwelles spiders (on Kauai) go back about 4 million years.

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Living fossils are lineages that have retained plesiomorphic traits through long time periods. It is expected that such lineages have both originated and diversified long ago. Such expectations have recently been challenged in some textbook examples of living fossils, notably in extant cycads and coelacanths. Using a phylogenetic approach, we tested the patterns of the origin and diversification of liphistiid spiders, a clade of spiders considered to be living fossils due to their retention of arachnid plesiomorphies and their exclusive grouping in Mesothelae, an ancient clade sister to all modern spiders. Facilitated by original sampling throughout their Asian range, we here provide the phylogenetic framework necessary for reconstructing liphistiid biogeographic history. All phylogenetic analyses support the monophyly of Liphistiidae and of eight genera. As the fossil evidence supports a Carboniferous Euramerican origin of Mesothelae, our dating analyses postulate a long eastward over-land dispersal towards the Asian origin of Liphistiidae during the Palaeogene (39-58 Ma). Contrary to expectations, diversification within extant liphistiid genera is relatively recent, in the Neogene and Late Palaeogene (4-24 Ma). While no over-water dispersal events are needed to explain their evolutionary history, the history of liphistiid spiders has the potential to play prominently in vicariant biogeographic studies.

The volcanic archipelago of the Canary Islands, 100 km colonized by dysderids from the continent. The present study provides a phylogenetic framework for an excep-off the northwestern coast of Africa, harbors 43 endemic species of the mostly circum-Mediterranean spider genus tional case of insular species radiation, an essential tool for unraveling the factors that have promoted this amaz-Dysdera (Araneae, Dysderidae). This amounts to approximately one-fourth of all known Dysdera species in an ing diversification. Species radiations in oceanic archipelagoes are excellent models for the study of speciation area that represents 0.1% of the range of the genus. In order to address the origin of this extraordinary number processes. ᭧ 2001 The Willi Hennig Society of endemic species, the phylogenetic relationships among all the endemic taxa and a sample of 27 continental species were reconstructed. A simultaneous cladistic analysis was performed on 66 morphological characters, 471 bp of the cytochrome oxidase I and 424 bp of the

Research in Macaronesia has led to substantial advances in ecology, evolution and conservation biology. We review the scientific developments achieved in this region, and outline promising research avenues enhancing conservation. Some of these discoveries indicate that the Macaronesian flora and fauna are composed of rather young lineages, not Tertiary relicts, predominantly of European origin. Macaronesia also seems to be an important source region for back-colonisation of continental fringe regions on both sides of the Atlantic. This group of archipelagos (Azores, Madeira, Selvagens, Canary Islands, and Cabo Verde) has been crucial to learn about the particularities of macroecological patterns and interaction networks on islands, providing evidence for the development of the General Dynamic Model of oceanic island biogeography and subsequent updates. However, in addition to exceptionally high richness of endemic species, Macaronesia is also home to a growing number of threatened species, along with invasive alien plants and animals. Several innovative conservation and management actions are in place to protect its biodiversity from these and other drivers of global change. The Macaronesian Islands are a well-suited field of study for island ecology and evolution research, mostly due to its special geological layout with 40 islands grouped within five archipelagos differing in geological age, climate and isolation. A large amount of data is now available for several groups of organisms on and around many of these islands. However, continued efforts should be made toward compiling new information on their biodiversity, to pursue various fruitful research avenues and develop appropriate conservation management tools.

Asexual reproduction by fissiparity is a frequent mode of reproduction in freshwater planarians (Turbellaria, Tricladida, Paludicola). Asexual populations pose a main taxonomical problem: to assign them to particular sexual species. We review here two case studies of asexual populations of freshwater triclads belonging to the genera Schmidtea and Dugesia. We show that karyotypes and morphology of the reproductive system of rare ex-fissiparous specimens led to identifing as Schmidtea mediterranea the few asexual populations of this genus. Instead, morphology and karyology were unable to deal with the frequent asexual populations of Dugesia. We used the internal transcribed spacer region (ITS-1) of ribosomal DNA to study 20 populations, sexual and asexual, of this genus. The pattern of sequence variation enabled the unambiguous assignment of all asexual populations to particular sexual species. The origin of asexual populations is briefly discussed.

The circum-Mediterranean spider genus Dysdera has undergone an outsanding species radiation in the volcanic archipelago of the Canary Islands. The present study deals with the endemic species that inhabit the older and ecologically distinct islands of Fuerteventura, Lanzarote and their nearby islets. A new species, Dysdera sanborondon, is described. The male of D. spinidorsum Wunderlich 1991, is described for the first time. Five species are redescribed: D. alegranzaensis Wunderlich 1991; D. Iancerotensis Simon 1907; D. longa Wunderlich 1991; D. nesiotes Simon 1907, and D. spinidorsum Wunderlich 1991. The species D. liostethus Simon 1907 is proposed to be a senior synonym of D. clavisetae Wunderlich 1991 and its presence in the eastern islands is considered to be doubtful. A neotype is designated for D. nesiotes. The distribution of D. alegranzaensis is extended to Lanzarote and the other northern islets. Dysdera nesiotes is reported for the first time in the eastern Canaries. Morphological affinities and distribution patterns are discussed. The remarkably lower number of endemic species harbored by the eastern islands, when compared with other Canarian islands similar in size but younger in age, is proposed to be the result of a major extinction event in the eastern Canaries due to climatic change.