The MACDIV project aimed to advance the fundamental knowledge of the factors responsible for existing diversity patterns using the Macaronesian Islands as model systems and spiders as model organisms (Malumbres‐Olarte et al. 2021). Focusing on local scales (plots 50 m x 50 m), MACDIV intended to dissect the taxonomic, functional and evolutionary basis of spatial heterogeneity in diversity, providing opportunities to understand some of the key processes that have led to the great diversification of life in Macaronesia.

The current manuscript is the third data paper contribution to the MACDIV project. The previous manuscripts focused on the spider species from the Azores (Malumbres-Olarte et al. 2019) and Madeira (Malumbres-Olarte et al. 2020) Archipelagos.

With the current contribution, we aim to provide the raw spider distribuition and abundance data for ten studied plots in Cabo Verde Islands and to respond to the Wallacean and Prestonian shortfalls. Respectively, the former hinders the knowledge of the distribution of species, while the latter hinders the knowledge of the abundance of species and both contribute to a great difficulty of establishment conservation priorities for invertebrates (Cardoso et al. 2011).

The general objectives of the MACDIV project were: i) To characterise cross-scale variations of Taxonomic Diversity (TD), Functional Diversity (FD) and Phylogenetic Diversity (PD) from plot to archipelago scales; ii) to identity the spatial, historical and environmental factors that may influence TD, FD and PD patterns at local scales; and iii) to determine resource-use differentiation between species to quantify the importance of ecological interactions within communities in driving local patterns.

Standardised inventories of spiders (Arachnida, Araneae) of dry habitats of Cabo Verde Archipelago (São Vicente and Santo Antão Islands)

The project was conceived and led by Paulo A.V. Borges, François Rigal and Pedro Cardoso.

Fieldwork (site selection and experimental setting): Maria Romeiras, Paulo A.V. Borges and Pedro Cardoso.

Fieldwork (authorisation): Direcção Nacional do Ambiente de Cabo Verde; INIDA – Instituto Nacional de Investigação e Desenvolvimento Agrário de Cabo Verde.

Fieldwork (spider sampling): Paulo A. V. Borges, Pedro Cardoso, Jagoba Malumbres-Olarte and Fernando Pereira (Fig. 1).

Parataxonomists: Alejandra Ros-Prieto and Paulo A. V. Borges.

Taxonomist: Luís Carlos Crespo.

Voucher specimen management was undertaken by Alejandra Ros Prieto and Paulo A. V. Borges.

Database management was undertaken by Alejandra Ros Prieto and Paulo A. V. Borges.

Darwin Core databases: Paulo A. V. Borges and Luís Carlos Crespo.

The Macaronesian Islands comprise four main archipelagos (Azores; Madeira and Selvagens; Canary Islands; Cabo Verde), with 40 islands larger than 1 km² covering a latitudinal range from 14.8°N to 39.7°N (Florencio et al. 2021).

Cabo Verde is an archipelago located in the central Atlantic Ocean composed of a group of volcanic islands and islets, ten main islands and several smaller islets and rocks. The islands are divided into three groups: northern (Santo Antão, São Vicente, Santa Luzia and São Nicolau), southern (Brava, Fogo and Santiago) and eastern (Maio, Boa Vista and Sal). The Archipelago is of volcanic origin and many of them still exhibit volcanic landscapes, including craters, lava flows and rugged terrain. The geography of Cabo Verde Islands is diverse. Some islands have lush, green landscapes with mountain ranges, while others are more arid and characterised by semi-desert conditions. Santo Antão, for example, is known for its dramatic mountainous terrain, while Boa Vista and Maio are flatter and have sand dunes. The Islands experience a tropical climate with distinct wet and dry seasons. The northern Islands receive more rainfall and tend to be greener, while the southern Islands are generally drier.

The geomorphological characteristics of our focal Islands of Santo Antão and São Vicente are marked by great ecological and edaphic diversity, similar to the other mountainous Islands of the Cabo Verde Archipelago (Santiago, Fogo, Brava and São Nicolau). The Island of Santo Antão has several volcanic cones, the highest point being Tope de Coroa (1980m). On the slopes facing the north-eastern trade winds, the erosion that has taken place over the course of the Island's evolution has been intense, shaping the landscape with several streams (e.g. Ribeira da Torre, Ribeira da Garça, Ribeira do Paúl, Ribeira da Janela) characterised by a sub-humid climate. Particularly, in the high-altitude valleys, a rich endemic flora can be found (e.g. Campylanthus glaber, Diplotaxis gorgadensis, Echium stenosiphon subsp. lindbergii, Phagnalon melanoleucum, Sonchus daltonii, Tolpis farinulosa, Umbilicus schmidtii). Other mountainous regions, such as Pico da Cruz (1585 m) and Planalto Leste (located in the Cova/Paul/Ribeira da Torre Natural Park), also show a great floristic diversity, including endemic plants together with exotic trees (e.g. Pinus canariensis, Eucalyptus and Cupressus) which constitute one of the most important forest resources of this Archipelago.

In the north-facing coastal cliffs of Santo Antão, characterised by temporary river valleys and escarpments, other endemic flora can still be found (e.g. Asparagus squarrosus, Cynanchum daltonii, Limonium braunii, Paronychia illecebroides, Polycarpaea gayi). On the southern, western and south-western slopes, the climate is more arid and the landscape is characterised by xerophytic species with sparse cover and a lack of endemic species (e.g. Abutilon pannosum, Calotropis procera, Cenchrus ciliaris and Cleome viscosa).

São Vicente Island is very arid, but above 400 m, the influence of the north-east trade winds in the main mountainous areas (i.e. Monte Verde - 750 m and Madeiral - 680 m) creates suitable ecological conditions for the survival of some endemic plant species (e.g. Aeonium gorgoneum, Diplotaxis vogelli, Echium stenosiphon subsp. stenosiphon, Limonium jovibarba, Lobularia canariensis subsp. spathulata). The lowland areas are covered by a very sparse herbaceous vegetation and the native vegetation is often heavily degraded and affected by overgrazing. Further, the high rate of invasion of the exotic tree - Prosopis juliflora (synonymous with Neltuma juliflora), has led to a reduction of other native trees, such as Tamarix senegalensis. On the north-eastern and eastern coastal areas of São Vicente Island, there are important plant communities, mainly associated with dunes and beach areas (e.g. Cistanche phelypaea, Patellifolia procumbens, Polycarpaea caboverdeana, Suaeda caboverdeana, Zygophyllum fontanesii) and salt marshes (e.g. Frankenia ericifolia subsp. caboverdeana, Patellifolia procumbens, Sesuvium portulacastrum and Zygophyllum gaetulum subsp. waterlotii).

Five sampling plots of 50 m x 50 m were installed in each of the two Islands (Santo Antão (Fig. 2) and São Vicente (Fig. 3)) at increasing distances from a reference plot (P1 at point 0, P2 at 0.1 km from P1, P3 at 1 km from P1, P4 at 5 km from P1 and P5 at 10 km from P1) in order to test beta-diversity models, as described in Malumbres‐Olarte et al. (2021) (Table 1).

All plots were located in areas where the habitat is arid and dominated by xerophytic community assemblages. In Santo Antão, the following plant species were present in the plots: Abutilon pannosum, Aristida adscensionis, Aristida funiculata, Asparagus squarrosus, Asteriscus daltonii subsp. vogelli, Blainvillea gayana, Calotropis procera, Campylanthus glaber subsp. spathulatus, Cenchrus ciliaris, Cleome viscosa, Commicarpus helenae, Crotalaria senegalensis, Cynanchum daltonii, Frankenia ericifolia subsp. ericifolia, Lavandula coronopifolia, Limonium braunii, Paronychia illecebroides, Polycarpaea gayi, Salvia aegyptiaca, Sesuvium portulacastrum, Trichodesma africanum and Zygophyllum creticum.

In São Vicente, the following plant species were present in the plots: Abutilon pannosum, Aerva javanica, Andrachne telephioides, Aristida adscensionis, Asparagus squarrosus, Cleome viscosa, Commicarpus helenae, Cynodon dactylon, Fagonia cretica, Zygophyllum creticum, Frankenia ericifolia subsp. ericifolia, Gymnocarpos sclerocephalus, Indigofera cordifólia, Limonium brunneri, Lotus alianus, Patellifolia procumbens, Polycarpaea gayi, Sesuvium portulacastrum, Suaeda caboverdeana, Tragus racemosus, Urochloa cabo-verdiana, Zygophyllum fontanesii and Zygophyllum simplex.

The sites in Santo Antão were located in a complex orographic terrain (Fig. 4a), often close to steep slopes (Fig. 4b), whereas the plots in São Vicente were mostly located in flat terrain (Fig. 5).

Fieldwork and initial research (2015-2018): FCT MACDIV (Macaronesian Islands as a testing ground to assess biodiversity drivers at multiple scales) was supported by Fundação para a Ciência e a Tecnologia – ref. FCT-PTDC/BIABIC/0054/2014.

Additional taxonomic work (2023): FCT-UIDB/00329/2020-2024 (Thematic Line 1 – integrated ecological assessment of environmental change on biodiversity).

To assess spider diversity, we employed the COBRA (Conservation Oriented Biodiversity Rapid Assessment) sampling protocol for habitats with no arboreal vegetation (Cardoso 2009). This protocol was later adapted to be the standard protocol to survey and monitor island communities (Borges et al. 2018). We employed the following sampling regime:

Vegetation sweeping (SW): We used a sweep-net with a 46 cm diameter opening for sweeping shrubs and tall herbaceous plants. A sweep-net sample consisted of one hour of sweeping, including the search for displaced spiders (Fig. 6a). The sampling protocol included four daytime (SWD) and four nighttime (SWN) samples, all performed at similar hours. We stored the specimens collected by this method in vials with 96% alcohol.

Night-time active aerial searching (AAS): Involved the systematic collection of spiders located above knee-level through manual, forceps, pooter or brush-assisted methods. We stored the specimens collected by this method as for the sweeping sampling. We did four samples of one hour per plot at similar hours.

Pitfall (PIT) Method: A total of 48 pitfall traps, which adhere to the European standard of 8 cm width at the top and a depth of approximately 12 cm (using 33 cl plastic cups), were strategically positioned just outside the boundary of each sampling plot. Traps were distributed evenly (around 4 m from each other), with 12 placed along each side of the square plot. They were 33% filled with 100% propylene glycol and left undisturbed in the field for a period of 14 days. To safeguard against predation, rainwater inundation and the capture of unwanted vertebrates (such as reptiles), plastic plates were positioned on stilts or rocks approximately 2 cm above the ground surface (Fig. 6b). In terms of data analyses, a group of four consecutive traps was considered as a single sample, totalling 12 samples per plot. However, in the current database, the individual 48 pitfall data are available (Note: pitfall samples missing in the event table are samples in which no spiders were collected).

In the laboratory, specimen sorting and spider identification followed standard procedures, using somatic and genitalic features for species identification, with literature available from the World Spider Catalogue (World Spider Catalogue 2023). Normally, juveniles are not identified to species level, but given the relative low number of species in insular faunas, more often than not we could match a juvenile to an adult, based on somatic resemblance. For this reason and to be consistent with previous publications (Malumbres-Olarte et al. 2019, Malumbres-Olarte et al. 2020), we considered juvenile specimens in abundance counts. A reference collection was made for all collected specimens (whether or not identified at the species level) by assigning them a morphospecies code number and deposited at the Dalberto Teixeira Pombo Insect Collection (DTP), University of Azores (Terceira Island, Portugal).

Cabo Verde Islands of Santo Antão and São Vicente.

16.76772 and 17.210328 Latitude; -25.38116 and -24.83459 Longitude.

All spiders (Arachnida, Araneae). The samples include 21 families.

The sampling occurred during a field expedition to the Islands of Santo Antão and São Vicente in October-November 2017. Sites were selected with the collaboration of local experts and the main fieldwork occurred between 30 October and 12 November. In the period between 14 and 23 November, pitfall traps were recovered.

Dalberto Teixeira Pombo insect collection at the University of Azores.

DTP

All specimens were preserved in 96% ethanol.

Dalberto Teixeira Pombo insect collection at the University of Azores (Curator: Paulo A. V. Borges).

Creative Commons Public Domain Waiver (CC-Zero)

Spiders from Macaronesia: Cabo Verde

https://doi.org/10.15468/p94j28

https://www.gbif.org/dataset/b8eeccd9-52dd-4e43-949e-818402577fa8; http://ipt.gbif.pt/ipt/resource?r=spiders_cabo_verde_2023

2

A total of 29 species were new records for Cabo Verde, being 15 new records for only Santo Antão, seven new records for only São Vicente and seven species were new records for both Islands. A total of 18 species were potentially new species to science or still undetermined members of previously-described taxa.

Given the abundance of new findings to the Cabo Verde Archipelago araneofauna, below we highlight the 29 cases of new records to the Archipelago, alongside the 18 unidentified species, for each commenting on their known distribution ranges, according to what is known from the WSC (World Spider Catalogue 2023).

Family Araneidae Clerck, 1757

Cyphalonotus CV89: This morphospecies comprises a likely undescribed species. It is not an Archipelago endemic, being also present on mainland Africa (Ghana), as identified by the first author from the collections at the Finnish Museum of Natural History. It was previously only known to us from undescribed males, with additional records here for the Archipelago from a male and 6 juveniles.

Neoscona quincasea Roberts, 1983: New record for the Archipelago. Widespread in the Afrotropics. Only two adult male specimens were newly collected, one in each Island.

Family Cheiracanthiidae Wagner, 1887

Cheiracanthium africanum Lessert, 1921: New record for the Archipelago and found from both adult males and females only in Santo Antão. Widespread in the Afrotropics.

Cheiracanthium CV6: We believe the genus Cheiracanthium needs to be revised carefully for the Cabo Verde Islands. The endemic species C. halophilum Schmidt & Piepho, 1994 is problematic as it might represent more than one species. It was described, based on females from Boa Vista Island (including the holotype) and males from both São Vicente and Maio Islands, plus subsequently an additional male from Santo Antão (Lotz 2007). The present morphospecies, Cheiracanthium CV6, was found exclusively in Santo Antão and, while the male matches with paratype males of C. halophilum, the female does not. A second endemic species of this genus, C. verdense Lotz, 2011 is known exclusively from males from São Vicente Island. We have found additional adult males and attribute several adult females collected alongside the males to it (the female remains undescribed).

Family Cithaeronidae Simon, 1893

Cithaeron reimoseri Platnick, 1991: This obscure species has a disjunct distribution with an original record from Eritrea, but later also from Brazil - where it is supposedly introduced, since the genus occurs naturally in Africa up to Asia. Its presence in Cabo Verde suggests this species might occur throughout the Afrotropics. New record for the Archipelago and found in São Vicente only.

Family Dictynidae O. Pickard-Cambridge, 1871

Dictyna CV4: This morphospecies comprises an unidentified species of uncertain genus, most likely Dictyna. Since there are no previous records of the genus Dictyna for Cabo Verde, this will be, at least, a new record for the Archipelago. The absence of revisionary works of Afrotropical Dictynidae limits the further identification of this morphospecies

Family Gnaphosidae Banks, 1892

Camillina cordifera (Tullgren, 1910): New record for the Archipelago and found only in Santo Antão. Widespread in the Afrotropics.

Marinarozelotes lyonneti (Audouin, 1826): New record for the Archipelago and found in both Islands. Widespread across the Macaronesia, Mediterranean up to Central Asia and introduced in the New World.

Micaria ignea O. Pickard-Cambridge, 1872: New record for the Archipelago and found in both Islands, being particularly abundant. Widespread across the Mediterranean, this is the southernmost record so far.

Poecilochroa senilis (O. Pickard-Cambridge, 1872): New record for the Archipelago and found only in São Vicente. Widespread across the Mediterranean, this is the southernmost record so far.

Smionia lineatipes (Purcell, 1908): New record for the Archipelago and found only in Santo Antão. Known from three southern African countries. It probably occurs across the entire Afrotropics.

Synaphosus syntheticus (Chamberlin, 1924): New record for the Archipelago and found only in Santo Antão. Known from the southern Mediterranean and supposedly introduced in the New World. This is the southernmost record for this species.

Family Linyphiidae Blackwall, 1859

Agyneta fuscipalpa (C. L. Koch, 1836): New record for the Archipelago and found only in Santo Antão. Widespread from Macaronesia up to Central Asia.

Lepthyphantes CV69: We are unsure about this genus identification. It is probably not a Lepthyphantes sensu stricto, but a related genus of this rather diverse group of spiders that all share many morphological traits.

Metaleptyphantes perexiguus (Simon & Fage, 1922): New record for the Archipelago and found only in Santo Antão. Widespread in the Afrotropics.

Family Oecobiidae Blackwall, 1862

Oecobius marathaus Tikader, 1962: New record for the Archipelago and found only in São Vicente. Widespread in the Afrotropics and supposedly introduced in the New World and Asia.

Oecobius pasteuri Berland & Millot, 1940: New record for the Archipelago and found only in Santo Antão. It presents a west African distribution.

Oecobius similis Kulczynski, 1909: New record for the Archipelago and found in both Islands. It presents a Macaronesian distribution, also reaching St. Helena.

Family Oonopidae Simon, 1890

Oonopidae CV103: This morphospecies comprises adult male and female specimens and belongs to an undescribed genus also found in other Afrotropical locations, according to unpublished information gathered by the first author.

Oonopidae CV172: This morphospecies comprises a singleton adult female, which we could not place in any known genera. There are many undescribed oonopid genera in the Afrotropics.

Opopaea concolor (Blackwall, 1859): New record for the Archipelago and found only in Santo Antão. It is widespread in the Afrotropics.

Opopaea deserticola Simon, 1892: New record for the Archipelago and found on both Islands. This species has not been recorded yet in the Afrotropics, is supposedly native for Asia, but was also found as a supposed introduction in the New World and some Pacific islands.

Opopaea speciosa (Lawrence, 1952): New record for the Archipelago and found only in São Vicente. The present record along with its disjunct distribution, in South Africa and Yemen, suggest a wider presence across the Afrotropics.

Opopaea CV193: This morphospecies comprises an unidentified species of which only a singleton male was found, with genital characters which seem to differentiate it from the remaining species.

Orchestina CV9: O. pavesii (Simon, 1873) was previously cited for Cabo Verde. We found specimens very similar to it, but with small differences in the male genitalia. Other closely-related species to O. pavesii are elsewhere differentiated by such minor differences and we tentatively attribute these specimens to a new species.

Xestaspis parmata Thorell, 1890: New record for the Archipelago and found only in Santo Antão. This species is native to Asia and supposedly introduced in both the New World and the Afrotropics.

Family Philodromidae Thorell, 1869

Tibellus nigeriensis Millot, 1942: New record for the Archipelago and found only in Santo Antão. It is only the second known location for this species, which was only known from Mali.

Family Pholcidae C. L. Koch, 1850

Modisimus culicinus (Simon, 1893): New record for the Archipelago and found only in Santo Antão. Native from South America, it is an introduction in many other locations, from Europe, Africa, Asia and Australia to the Pacific Islands.

Family Prodidomidae Simon, 1884

Eleleis luderitz Rodrigues & Rheims 2020: New record for the Archipelago and found only in São Vicente. Only known from Namibia.

Prodidomus CV34: This morphospecies comprises a single, non-identified male from the Island of Santo Antão. African species of Prodidomus do not have recent revisions available.

Prodidomus CV134: This morphospecies comprises several females from the Island of São Vicente. We could tentatively assign them to the previous male, but the possibility of both being sibling endemics makes it more reasonable to leave them as separate species for now.

Family Salticidae Blackwall, 1841

Langona CV158: This morphospecies comprises a single unidentified female from São Vicente. Langona is widespread across the Afrotropics and the Sahel with 45 species (World Spider Catalogue 2023), but the non-revised status of many species hinders the identification of single females.

Langona CV194: Same as above.

Phlegra CV195: This morphospecies comprises a single unidentified female from São Vicente. Although initially identified as P. bifurcata, it is probably another species.

Wesolowskana CV190: This morphospecies comprises a single female from the Island of Santo Antão, showing great resemblance to the two known species of this endemic genus of Cabo Verde. We believe this can be an additional third species of this genus.

Family Scytodidae Blackwall, 1864

Scytodes univittata Simon, 1882: New record for the Archipelago and found only in Santo Antão. Native to eastern Mediterranean up to India, it is an introduction in the New World and also Canary Islands.

Family Tetrablemmidae O. Pickard-Cambridge, 1873

Tetrablemma CV31: This morphospecies comprises an unidentified species. This is the first record of a tetrablemmid for Cabo Verde, collected in both the Islands of Santo Antão and São Vicente. This family of minute spiders is not revised in the Afrotropical Region.

Family Theridiidae Sundevall, 1833

Enoplognatha diversa (Blackwall, 1859): New record for the Archipelago and found only in Santo Antão. Native to the Mediterranean.

Euryopis episinoides (Walckenaer, 1847): New record for the Archipelago and found only in São Vicente. Native to the Mediterranean, it is also an introduction in South Africa, Reunion, India and China.

Eurypoena tuberosa (Wunderlich, 1987): New record for the Archipelago found on both Islands. Previously described from the Canary Islands.

Lasaeola CV64: An unidentified species of this genus of tiny spiders, which are present from the New World to Asia.

Steatoda erigoniformis (O. Pickard-Cambridge, 1872): New record for the Archipelago and found only in São Vicente. Native to the eastern Mediterranean up to Japan, it is an introduction in the New World and South Africa.

Theridion CV39: This morphospecies comprises an unidentified species of this very large genus. Males and females were collected from the Island of Santo Antão.

Theridion CV178: This morphospecies comprises an unidentified species of this very large genus. Only a single female was collected from the Island of São Vicente.

Theridion melanostictum O. Pickard-Cambridge, 1876: New record for the Archipelago and found only in Santo Antão. A widespread species, with a distribution from the Mediterranean up to Japan, it is an introduction in several places in the New World.

Family Thomisidae Sundevall, 1833

Runcinia flavida (Simon, 1881): New record for the Archipelago and found only in Santo Antão. Widespread in Africa.

Family Uloboridae Thorell, 1869

Uloborus walckenaerius Latreille, 1806: New record for the Archipelago found on both Islands. An endemic species, Uloborus rufus Schmidt & Krause, 1995 is also known for the Archipelago. After reviewing the female genitalic characters of U. rufus from published information, but without checking any type material, we suspect it may be a synonymy to other species. U. walckenaerius has a distribution ranging from Macaronesia to Asia, also found, possibly introduced, in a coastal forest reserve in Ghana (collections of the Finnish Museum of Natural History) and in South Africa (Dippenaar-Schoeman et al. 2020).