Thriving in dry conditions: on the Neotropical spider genus Galapa (Araneae: Pholcidae).

The genus Galapa Huber, 2000 includes tiny spiders (body length <1.5 mm) restricted to semi-arid habitats. It has long been thought to be endemic to the Galapagos Islands until G. spiniphila Huber, 2020 was described from the Venezuelan Paraguan Peninsula. Here, we support this generic assignment with molecular (CO1) data and describe two new species from Colombia (G. gabito Huber sp. n.) and Costa Rica (G. murphyi Huber sp. n.), showing that the genus is actually widely distributed. Distribution modelling identifies several high suitability areas for Galapa, all of which are poorly sampled with respect to Pholcidae (ranging from Nicaragua to northern Peru and Guiana). Our results suggest a strong sampling bias against spiders restricted to dry tropical regions and habitats.

Notes on Chisosa (Araneae, Pholcidae), with the description of a new species from Mexico.

The genus Chisosa Huber, 2000 previously included only three species of small to tiny North American and Caribbean spiders that are rare in collections and poorly studied. Originally placed in the subfamily Ninetinae, Chisosa is currently considered a representative of Arteminae, close to the North American genus Physocyclus Simon, 1893. This placement has been suggested by molecular data, and it affects the interpretation of morphological characters that were originally thought to support the monophyly of Chisosa: they are shared with Physocyclus and thus plesiomorphic for Chisosa. Here we describe a new species from Mexico, C. calapa sp. nov., and restudy in detail the morphology (incl. ultrastructure) of the type species C. diluta (Gertsch & Mulaik, 1940) and of C. caquetio Huber, 2019, based on newly collected material. We document further similarities with Physocyclus but find only weak morphological support for the monophyly of Chisosa (body size reduction and short legs). In addition, we document surprisingly large genetic distances among C. caquetio specimens from Curaao (>14% CO1 K2P distances), possibly indicating species limits. Finally, we propose that the Dominican amber genus Serratochorus Wunderlich, 1988, based on a single male specimen, is also phylogenetically close to Chisosa and should be included in future studies on these enigmatic spiders.

A trait database and updated checklist for European subterranean spiders.

Species traits are an essential currency in ecology, evolution, biogeography, and conservation biology. However, trait databases are unavailable for most organisms, especially those living in difficult-to-access habitats such as caves and other subterranean ecosystems. We compiled an expert-curated trait database for subterranean spiders in Europe using both literature data (including grey literature published in many different languages) and direct morphological measurements whenever specimens were available to us. We started by updating the checklist of European subterranean spiders, now including 512 species across 20 families, of which at least 192 have been found uniquely in subterranean habitats. For each of these species, we compiled 64 traits. The trait database encompasses morphological measures, including several traits related to subterranean adaptation, and ecological traits referring to habitat preference, dispersal, and feeding strategies. By making these data freely available, we open up opportunities for exploring different research questions, from the quantification of functional dimensions of subterranean adaptation to the study of spatial patterns in functional diversity across European caves.

Evolutionary morphology of sperm in pholcid spiders (Pholcidae, Synspermiata).

BACKGROUND: Pholcidae represent one of the largest and most diverse spider families and have been subject to various studies regarding behavior and reproductive biology. In contrast to the solid knowledge on phylogeny and general reproductive morphology, the primary male reproductive system is strongly understudied, as it has been addressed only for few species. Those studies however suggested a high diversity of sperm and seminal secretions across the family. To address this disparity and reconstruct the evolution of sperm traits, we investigate the primary male reproductive system of pholcid spiders by means of light, X-ray, and transmission electron microscopy using a comprehensive taxon sampling with 46 species from 33 genera, representing all five subfamilies. RESULTS: Our data show a high disparity of sperm morphology and seminal secretions within pholcids. We document several sperm characters that are unique for pholcids, such as a helical band (Pholcinae) or a lamellate posterior centriolar adjunct material (Modisiminae). Character mapping revealed several putative synapomorphies for individual taxa. With regard to sperm transfer forms, we found that synspermia occur only in the subfamily Ninetinae, whereas the other subfamilies have cleistospermia. In several species with cleistospermia, we demonstrate that spermatids remain fused until late stages of spermiogenesis before ultimately separating shortly before the coiling process. Additionally, we explored the previously hypothesized correlation between sperm size and minimum diameter of the spermophor in the male palpal organ. We show that synspermia differ strongly in size whereas cleistospermia are rather uniform, but neither transfer form is positively correlated with the diameter of the spermophor. CONCLUSIONS: Our data revealed a dynamic evolution of sperm characters, with convergences across all subfamilies and a high level of homoplasy. The present diversity can be related to subfamily level and allows for assignments of specific subtypes of spermatozoa. Our observations support the idea that Ninetinae are an ancestral clade within Pholcidae that have retained synspermia and that synspermia represent the ancestral sperm transfer form of Pholcidae.

Karyotype differentiation and male meiosis in European clades of the spider genus Pholcus (Araneae, Pholcidae).

Haplogyne araneomorphs are a diverse spider clade. Their karyotypes are usually predominated by biarmed (i.e., metacentric and submetacentric) chromosomes and have a specific sex chromosome system, X1X2Y. These features are probably ancestral for haplogynes. Nucleolus organizer regions (NORs) spread frequently from autosomes to sex chromosomes in these spiders. This study focuses on pholcids (Pholcidae), a highly diverse haplogyne family. Despite considerable recent progress in pholcid cytogenetics, knowledge on many clades remains insufficient including the most species-rich pholcid genus, Pholcus Walckenaer, 1805. To characterize the karyotype differentiation of Pholcus in Europe, we compared karyotypes, sex chromosomes, NORs, and male meiosis of seven species [P.alticeps Spassky, 1932; P.creticus Senglet, 1971; P.dentatus Wunderlich, 1995; P.fuerteventurensis Wunderlich, 1992; P.phalangioides (Fuesslin, 1775); P.opilionoides (Schrank, 1781); P.silvai Wunderlich, 1995] representing the dominant species groups in this region. The species studied show several features ancestral for Pholcus, namely the 2n♂ = 25, the X1X2Y system, and a karyotype predominated by biarmed chromosomes. Most taxa have a large acrocentric NOR-bearing pair, which evolved from a biarmed pair by a pericentric inversion. In some lineages, the acrocentric pair reverted to biarmed. Closely related species often differ in the morphology of some chromosome pairs, probably resulting from pericentric inversions and/or translocations. Such rearrangements have been implicated in the formation of reproductive barriers. While the X1 and Y chromosomes retain their ancestral metacentric morphology, the X2 chromosome shows a derived (acrocentric or subtelocentric) morphology. Pairing of this element is usually modified during male meiosis. NOR patterns are very diverse. The ancestral karyotype of Pholcus contained five or six terminal NORs including three X chromosome-linked loci. The number of NORs has been frequently reduced during evolution. In the Macaronesian clade, there is only a single NOR-bearing pair. Sex chromosome-linked NORs are lost in Madeiran species and in P.creticus. Our study revealed two cytotypes in the synanthropic species P.phalangioides (Madeiran and Czech), which differ by their NOR pattern and chromosome morphology. In the Czech cytotype, the large acrocentric pair was transformed into a biarmed pair by pericentric inversion.

Is it time to describe new species without diagnoses?A comment on Sharkey et al. (2021).

New methods in taxonomy and systematics can influence the overall practice of formally naming and describing biodiversity. DNA barcoding has been controversial since its emergence, but now, large scale species descriptions exclusively based on barcodes have created what can be called a 'new quality of performance. Its limitations are discussed from different perspectives: nomenclature, general pragmatism, and problems of DNA-based species delimitation in the light of the central aim of achieving a robust and stable nomenclature of organisms, essential for all applications of biodiversity research. This issue needs to be addressed to prevent restraining the progress of taxonomy and its ability to contribute to modern science.

First Northwest African species of the spider genus Artema, from caves in Morocco, with notes on body size in pholcid spiders (Araneae: Pholcidae).

The genus Artema Walckenaer, 1837 includes some of the largest pholcid spiders and is geographically largely restricted to Central Asia, the Middle East, the Arabian Peninsula, and the eastern Mediterranean. One species has previously been known from West Africa. The first known Moroccan species, A. martensi sp. n., extends the known distribution of the genus to the northwestern limit of the African continent. The species is described from two caves in the western Anti-Atlas, but it is not troglomorphic. A comparative analysis of male carapace width in 1632 pholcid species shows that A. martensi sp. n. is the largest known pholcid with respect to this character. Plots of mean carapace sizes of newly described species on periods of time (50 years, 20 years) show that the mean sizes of newly described species have been constantly decreasing.

Evolutionary pattern of karyotypes and meiosis in pholcid spiders (Araneae: Pholcidae): implications for reconstructing chromosome evolution of araneomorph spiders.

BACKGROUND: Despite progress in genomic analysis of spiders, their chromosome evolution is not satisfactorily understood. Most information on spider chromosomes concerns the most diversified clade, entelegyne araneomorphs. Other clades are far less studied. Our study focused on haplogyne araneomorphs, which are remarkable for their unusual sex chromosome systems and for the co-evolution of sex chromosomes and nucleolus organizer regions (NORs); some haplogynes exhibit holokinetic chromosomes. To trace the karyotype evolution of haplogynes on the family level, we analysed the number and morphology of chromosomes, sex chromosomes, NORs, and meiosis in pholcids, which are among the most diverse haplogyne families. The evolution of spider NORs is largely unknown. RESULTS: Our study is based on an extensive set of species representing all major pholcid clades. Pholcids exhibit a low 2n and predominance of biarmed chromosomes, which are typical haplogyne features. Sex chromosomes and NOR patterns of pholcids are diversified. We revealed six sex chromosome systems in pholcids (X0, XY, X1X20, X1X2X30, X1X2Y, and X1X2X3X4Y). The number of NOR loci ranges from one to nine. In some clades, NORs are also found on sex chromosomes. CONCLUSIONS: The evolution of cytogenetic characters was largely derived from character mapping on a recently published molecular phylogeny of the family. Based on an extensive set of species and mapping of their characters, numerous conclusions regarding the karyotype evolution of pholcids and spiders can be drawn. Our results suggest frequent autosome-autosome and autosome-sex chromosome rearrangements during pholcid evolution. Such events have previously been attributed to the reproductive isolation of species. The peculiar X1X2Y system is probably ancestral for haplogynes. Chromosomes of the X1X2Y system differ considerably in their pattern of evolution. In some pholcid clades, the X1X2Y system has transformed into the X1X20 or XY systems, and subsequently into the X0 system. The X1X2X30 system of Smeringopus pallidus probably arose from the X1X20 system by an X chromosome fission. The X1X2X3X4Y system of Kambiwa probably evolved from the X1X2Y system by integration of a chromosome pair. Nucleolus organizer regions have frequently expanded on sex chromosomes, most probably by ectopic recombination. Our data suggest the involvement of sex chromosome-linked NORs in achiasmatic pairing.

Revision of the spider genus Hoplopholcus Kulczynski (Araneae, Pholcidae).

Hoplopholcus Kulczynski, 1908 is a genus of relatively large pholcid spiders, ranging from eastern Central Europe to Crete, the Levant, and Georgia. Species in this genus are often difficult to distinguish from each other, and the reexamination of previously published material revealed many misidentifications. The present study provides redescriptions of the ten previously described species and descriptions of six new species, all based on males and females: Hoplopholcus suluin sp. n., H. konya sp. n., H. atik sp. n., and H. bursa sp. n. from Turkey, H. gazipasa sp. n. from Turkey and Greece, and H. dim sp. n. from Turkey and Cyprus. The main conclusion is that several species need further investigation, based on focused sampling and ideally including molecular data. Some species seem to include morphologically distinct epigean and hypogean populations; others may eventually need to be split into two or more species. Further undescribed species are most likely to occur in Turkey.

Filling the gaps: descriptions of unnamed species included in the latest molecular phylogeny of Pholcidae (Araneae).

This paper provides formal descriptions of some of the unnamed taxa that were included in the most recent molecular phylogeny of pholcid spiders (Eberle et al. 2018, BMC Evolutionary Biology, 18, 141). The focus is on new genera and on species that belong to recently revised genera. Eight new genera and 25 new species are formally described. In Arteminae, three new species are described in Artema Walckenaer, 1837: A. bahla sp. n., A. ghubrat sp. n., and A. dhofar sp. n. (all from Oman); five new species in Arnapa gen. n. (eastern Indonesia and New Guinea): A. arfak sp. n., A. tinoor sp. n., A. manokwari sp. n., A. meja sp. n., A. tolire sp. n.; and one new species in Chisosa Huber, 2000: C. caquetio sp. n. (Netherlands Antilles). In Ninetinae, three new monotypic genera are described: Pemona gen. n., with the type species P. sapo sp. n. (Venezuela); Pinocchio gen. n., with the type species P. barauna sp. n. (Brazil); and Magana gen. n., with the type species M. velox sp. n. (Oman). In Modisiminae, three new species are described in Chibchea Huber, 2000 (all from Brazil): C. amapa sp. n., C. santosi sp. n., and C. hamadae sp. n.; one new species in Psilochorus Simon, 1893: P. bromelicolus sp. n. (Brazil); and three new monotypic genera, all from Brazil: Arenita gen. n., with the type species A. fazendinha sp. n.; Kairona gen. n., with the type species K. selva sp. n.; and Saciperere gen. n., with the type species S. catuaba sp. n. In Pholcinae, a new monotypic genus is described: Giloloa gen. n., with the type species G. sofifi sp. n. (Indonesia); three new species in the genus Aetana Huber, 2005 (all from Indonesia): A. ternate sp. n.; A. mokwam sp. n.; A. ondawamei sp. n.; and two new species in the genus Panjange Deeleman-Reinhold Deeleman, 1983 (both from Indonesia): P. thomi sp. n., and P. togutil sp. n.        Artema ghubrat is a cave-dwelling species and the only (slightly) troglomorphic representative of Arteminae; A. dhofar is presumably the closest known relative of the pantropical and synanthropic A. atlanta. The new genus Arnapa is probably species rich in eastern Indonesia and New Guinea but poorly collected; its morphological delimitation from other Australasian Arteminae (Wugigarra Huber, 2001; Holocneminus Berland, 1942; Trichocyclus Simon, 1908) needs further study. Arnapa nigromaculatus (Kulczynski, 1911) comb. n. is newly transferred from Psilochorus. Pemona sapo is the first representative of Ninetinae from Venezuela. The genus Chibchea, previously known from the Andes only, is for the first time recorded from Brazil/lowland Amazonia. Arenita fazendinha is among the few species in Pholcidae with extremely reduced procursus and barely modified male chelicerae. Kairona selva is unique among Pholcidae for its brush of strong hairs on a median horn anteriorly on the ocular area. Saciperere catuaba is one of only four pholcid species currently known to occur both in the Amazon and in the Atlantic Forest; however, variation indicates that more than one species might be included. It is among the few spiders known to have asymmetric genitalia (antisymmetric female internal genitalia). The Brazilian Psilochorus bromelicolus is the first South American Psilochorus of which both sexes are adequately described; however, the assignment to Psilochorus is tentative. Aetana ternate has extremely elongated procursi and accordingly elongated female internal genitalia. Aetana ondawamei and A. mokwam have almost identical male pedipalps and chelicerae (except for size) but differ clearly in the female genitalia.

The pholcid spiders of Sri Lanka (Araneae: Pholcidae).

As part of the Western Ghats-Sri Lanka biodiversity hotspot, Sri Lanka harbors a rich and diverse fauna, especially in the perhumid southwestern part of the island. However, many invertebrate groups such as spiders continue to be poorly studied. The present paper reviews our knowledge about Pholcidae, a family of spiders that is well represented in Sri Lanka, both by numerous (10) introduced species and by a rich native fauna in five genera (described native Sri Lankan species in parentheses): Belisana Thorell, 1898 (6), Leptopholcus Simon, 1893 (1), Pholcus Walckenaer, 1805 (4), Tissahamia Huber, 2018 (4), and Wanniyala Huber Benjamin, 2005 (9). Fourteen species are newly described: Belisana minneriya sp. n., B. badulla sp. n., B. gowindahela sp. n.; Pholcus metta sp. n., P. puranappui sp. n., P. uva sp. n.; Tissahamia karuna sp. n.; Wanniyala mudita sp. n., W. orientalis sp. n., W. upekkha sp. n., W. ohiya sp. n., W. viharekele sp. n., W. mapalena sp. n., and W. labugama sp. n.. All new species are described from males and females. New Sri Lankan records are given for 16 previously described species. Distribution data suggest that most or all of the 24 native species might be endemic to Sri Lanka, but the Indian pholcid fauna remains almost entirely unknown.

The phylogeny of pholcid spiders: a critical evaluation of relationships suggested by molecular data (Araneae, Pholcidae).

With almost 600 species, the latest molecular phylogeny of pholcid spiders (Eberle et al. 2018, BMC Evolutionary Biology) more than triples the largest previously available molecular phylogeny of the family. At the level of genera, the coverage is high (86%, i.e., 75 of the 87 named genera), and at the level of subfamilies it is complete. The present paper is an effort to critically evaluate the implications of this phylogeny for pholcid systematics. The analyses largely support the division of Pholcidae into five subfamilies: Ninetinae, Arteminae, Modisiminae, Smeringopinae, and Pholcinae. Their compositions are largely unchanged except that Chisosa Huber, 2000 is moved from Ninetinae to Arteminae. The positions of Artema Walckenaer, 1837 and Priscula Simon, 1893 in this system remain dubious. Relationships among subfamilies remain weakly supported, except for the sister group relationship between Smeringopinae and Pholcinae. Several major clades within subfamilies are separated from each other along geographical boundaries; for example within Modisiminae a South American clade and a Central + North American + Caribbean clade, and within Smeringopinae a Sub-Saharan clade and a clade ranging from the Mediterranean to Central Asia. Central + North American + Caribbean clades in both Ninetinae and Modisiminae may originate from South American ancestors. Many taxonomic changes are suggested by the data, some of which are formally implemented herein. Two new genera result from the splitting of Calapnita Simon, 1892 and Panjange Deeleman-Reinhold & Deeleman, 1983, respectively: Nipisa Huber, gen. n.; and Apokayana Huber, gen. n. Nine new genera result from splitting of Pholcus: Cantikus Huber, gen. n.; Kelabita Huber, gen. n.; Kintaqa Huber, gen. n.; Muruta Huber, gen. n.; Meraha Huber, gen. n.; Paiwana Huber, gen. n.; Pribumia Huber, gen. n.; Teranga Huber, gen. n.; and Tissahamia Huber, gen. n. Two genera are newly synonymized: Platnicknia Özdikmen & Demir, 2009 is synonymized with Modisimus Simon, 1893; Sihala Huber, 2011 is synonymized with Pholcus Walckenaer, 1805. Pholcusagadir Huber, 2011 is moved to Micropholcus Deeleman-Reinhold & Prinsen, 1987, resulting in the new combination Micropholcusagadir (Huber, 2011).

Microhabitat change drives diversification in pholcid spiders.

BACKGROUND: Microhabitat changes are thought to be among the main drivers of diversification. However, this conclusion is mostly based on studies on vertebrates. Here, we investigate the influence of microhabitat on diversification rates in pholcid spiders (Araneae, Pholcidae). Diversification analyses were conducted in the framework of the largest molecular phylogeny of pholcid spiders to date based on three nuclear and three mitochondrial loci from 600 species representing more than 85% of the currently described pholcid genera. RESULTS: Assessments of ancestral microhabitat revealed frequent evolutionary change. In particular, within the largest subfamily Pholcinae, numerous changes from near-ground habitats towards leaves and back were found. In general, taxa occupying leaves and large sheltered spaces had higher diversification rates than ground-dwelling taxa. Shifts in speciation rate were found in leaf- and space-dwelling taxa. CONCLUSIONS: Our analyses result in one of the most comprehensive phylogenies available for a major spider family and provide a framework for any subsequent studies of pholcid spider biology. Diversification analyses strongly suggest that microhabitat is an important factor influencing diversification patterns in pholcid spiders.

The South American spider genera Mesabolivar and Carapoia (Araneae, Pholcidae): new species and a framework for redrawing generic limits.

The South American genera Mesabolivar González-Sponga, 1998 and Carapoia González-Sponga, 1998 are among the most species-rich pholcid genera in the Neotropics. Representatives of both genera occupy a wide range of microhabitats from the leaf litter to high among the vegetation, resulting in a morphological and behavioral diversity that complicates not only identification in the field but also the establishment of generic limits. The present paper is primarily an effort to improve the foundation for future work on these genera by describing new species and unknown sexes, by redescribing poorly known species, and by adding distribution data for known species. In order to provide some structure for the 72 species treated herein, the genera are divided into operational species groups, based in part on previous morphological and molecular phylogenetic analyses, in part on similarity. The following 47 species are newly described. In Mesabolivar: M. acrensis, M. amadoi, M. amanaye, M. amazonicus, M. baianus, M. bico, M. bicuspis, M. borgesi, M. buraquinho, M. camacan, M. catarinensis, M. chapeco, M. claricae, M. constrictus, M. guaycolec, M. inmanis, M. itajai, M. jamari, M. kaingang, M. madalena, M. macushi, M. maraba, M. mimoso, M. murici, M. niteroi, M. pallens, M. saci, M. sepitus, M. serrapelada, M. similis, M. tabatinga, M. tapajos, M. turvo, M. yucuma. In Carapoia: C. agilis, C. bispina, C. djavani, C. exigua, C. kaxinawa, C. maculata, C. munduruku, C. pulchra, C. rubra, C. suassunai, C. tapajos, C. tenuis, C. utinga. Three poorly known species are redescribed in detail: M. spinosus (González-Sponga, 2005), M. anseriformis (González-Sponga, 2011), and M. azureus (Badcock, 1932). The previously unknown females are described for M. anseriformis and M. rudilapsi Machado et al., 2007; the previously unknown male is described for M. argentinensis (Mello-Leitão, 1938). The monotypic genus Teuia Huber, 2000 is newly synonymized with Mesabolivar, resulting in the new combination Mesabolivar beckeri (Huber, 2000). Psilochorus fluminensis Mello-Leitão, 1918 and Blechroscelis aurantia Mello-Leitão, 1940 are newly synonymized with Mesabolivar togatus (Keyserling, 1891). Three species are formally transferred from Mesabolivar to Carapoia: C. cambridgei (Mello-Leitão, 1947), C. lutea (Keyserling, 1891), and C. levii (Huber, 2000).

New species of Idris Förster (Hymenoptera, Platygastroidea) from southeast Asia, parasitoids of the eggs of pholcid spiders (Araneae, Pholcidae).

Four new species of the genus Idris Förster (Hymenoptera: Platygastroidea), reared from the eggs of pholcid spiders (Araneae: Pholcidae) in southeast Asia are described on the basis of external morphology and the barcode region of the mitochondrial COI gene. The new species and their hosts are: I.badius Johnson & Chen, sp. n. (ex Nipisaphyllicola (Deeleman-Reinhold), Panjangehamiguitan Huber), I.balteus Johnson & Chen, sp. n. (ex Panjangecamiguin Huber), I.curtus Johnson & Chen, sp. n. (ex Calapnitanunezae Huber, Panjangecamiguin Huber, Tissahamiabukittimah (Huber), Uthinaluzonica Simon), and I.fusciceps (ex Belisanakhaosok Huber).

Revision of the Venezuelan spider genus Stenosfemuraia González-Sponga, with new generic and specific synonymies (Araneae, Pholcidae).

The Venezuelan genus Stenosfemuraia González-Sponga, 1998 is revised, with redescriptions of its three named species: S. parva González-Sponga, 1998 (type species); S. cuadrata González-Sponga, 2005; and S. pilosa (González-Sponga, 2005) n. comb. The latter species was originally described as Codazziella pilosa, and six years later again as Chichiriviche costanero González-Sponga, 2011 (n. syn.). The monotypic genera Codazziella González-Sponga, 2005 and Chichiriviche González-Sponga, 2011 are thus newly synonymized with Stenosfemuraia. The genus appears restricted to the Cordillera de la Costa region where the spiders occupy near-ground microhabitats in medium to high elevation forests.

Revision and cladistic analysis of the Southeast Asian leaf-dwelling spider genus Calapnita Simon (Araneae, Pholcidae).

The Southeast Asian pholcid genus Calapnita Simon, 1892 is revised, with descriptions of 17 new species, five of them in the phyllicola group (Borneo: C. lehi, C. kubah, C. bidayuh, C. bankirai; Malay Peninsula, Sumatra, Java: C. anai), 12 in the vermiformis group (Borneo: C. bario, C. bariengi, C. magaseng, C. dayak, C. lawangan, C. loksado; Sulawesi: C. bugis; Philippines: C. bohol, C. dinagat, C. mae, C. nunezae, C. maragusan). New records are listed for six of the eight previously described species. A morphological cladistic analysis supports the monophyly of Calapnita and of its two previously proposed species groups and presents several new phylogenetically informative characters. New data are presented about ultrastructure and natural history (web, egg-sac, egg parasitism).

Spider diversity and endemism in a South American hotspot: 20 new species of Carapoia (Araneae: Pholcidae) from Brazil's Atlantic Forest.

The Atlantic Forest along the eastern South American coast is widely recognized as a hotspot with extreme levels of diversity, endemism, and threat. A megatransect study (2003-2015) focusing on pholcid spiders and covering 48 localities across a large part of the Brazilian Atlantic Forest resulted in 132 morphospecies, of which 81% were new to science. The present paper deals with the species of Carapoia González-Sponga, 1998 collected during this campaign. The endemism level is 100%, i.e. all 26 species of Carapoia in the Atlantic Forest are not known from (and not likely to occur) anywhere else. While few species (all of them with non-overlapping ranges) occur in the most southern and northern regions, the central region (between Rio Doce and Rio Paraguaçu; largely equivalent to what has been called the 'Bahia refuge') is characterized by high diversity and up to five species per locality. The following species are newly described (from South to North): C. voltavelha (Santa Catarina); C. macacu, C. divisa (Rio de Janeiro); C. nairae, C. capixaba, C. mirim, C. patafina (Espírito Santo); C. pau, C. gracilis, C. zumbii, C. dandarae, C. marceloi, C. viridis, C. jiboia, C. carvalhoi, C. carybei (Bahia); C. alagoas (Alagoas); C. saltinho, C. abdita (Pernambuco); C. septentrionalis (Pernambuco to Rio Grande do Norte). New records and amendments are given for most previously described Atlantic Forest species.