Silk, especially spider and insect silk, is a highly versatile biomaterial with potential applications in biomedicine, materials science, and biomimetic engineering. The primary structure of silk proteins is the basis for the mechanical properties of silk fibers. Biotechnologies such as single-molecule sequencing have facilitated an increasing number of reports on new silk genes and assembled silk proteins. Therefore, this review aims to provide a comprehensive overview of the recent advances in representative spider and insect silk proteins, focusing on identification methods, sequence characteristics, and de novo design and assembly. The review discusses three identification methods for silk genes: polymerase chain reaction (PCR)-based sequencing, PCR-free cloning and sequencing, and whole-genome sequencing. Moreover, it reveals the main spider and insect silk proteins and their sequences. Subsequent de novo assembly of artificial silk is covered and future research directions in the field of silk proteins, including new silk genes, customizable artificial silk, and the expansion of silk production and applications are discussed. This review provides a basis for the genetic aspects of silk production and the potential applications of artificial silk in material science and biomedical engineering.

Photographs of the type specimens of nine spider species described by Barrion et al. (2013) from Hainan Island, China, considered as valid taxa in this study, are provided. Among them, three new combinations are proposed: Clubiona pandalira (Barrion-Dupo, Barrion & Heong, 2013) comb. nov. (ex Nusatidia Deeleman-Reinhold, 2001); Dictis edwardsi (Barrion, Barrion-Dupo & Heong, 2013) comb. nov. (ex Scytodes Latreille, 1804); and Nesioneta mingshengzhui (Barrion, Barrion-Dupo & Heong, 2013) comb. nov. (ex Meioneta Hull, 1920). Thirty-one new synonyms are proposed and three species are considered as nomina dubia.

The spider genus Echinax Deeleman-Reinhold, 2001 is reviewed in China. Two new species, E. breviducta sp. nov. () and E. wuzhishan sp. nov. (), are described and illustrated. The female of E. baisha Lu & Li, 2023 is reported for the first time, and three known species, E. anlongensis Yang, Song & Zhu, 2004, E. oxyopoides (Deeleman-Reinhold, 1995) and E. panache Deeleman-Reinhold, 2001, are illustrated.

The euophryine genus Chalcovietnamicus Marusik, 1991, a member of the Laufeia group of genera, is reviewed, and four new species from southern China and Southeast Asia are described with both sexes: Chalcovietnamicus logunovi Yu, Maddison & Zhang, sp. nov., C. marusiki Yu, Maddison & Zhang, sp. nov., C. terbakar Yu, Maddison & Zhang, sp. nov. and C. weihangi Yu & Zhang, sp. nov.. The monotypic genus Junxattus Prszyski & Deeleman-Reinhold, 2012 syn. nov. is considered as a junior synonym of Chalcovietnamicus Marusik, 1991, and Parvattus Zhang & Maddison, 2012 is revalidated and removed from synonymy with Chalcovietnamicus Marusik, 1991. The previously unknown female of C. vietnamensis (abka, 1985) is described based on specimens from Vietnam and Singapore. All species of Chalcovietnamicus are assigned to two species groups (daiqini-group and vietnamensis-group), except C. naga Logunov, 2020 that is herein considered as an incertae sedis.

The family Cyrtaucheniidae is seldom found in the Americas, only 10 species are known to occur. Herein we described fourteen new species for the family Cyrtaucheniidae, all belonging to the genus Bolostromus from Central America and South America: Bolostromus busu n. sp. (female); B. devriesi n. sp. (female); B. epiphyticus n. sp. (male, female); B. fonsecai n. sp. (male); B. hubeni n. sp. (male, female); B. italoi n. sp. (female); B. laheredia n. sp. (male); B. losrios n. sp. (male); B. nischki n. sp. (male); B. urku n. sp. (male), B. primus n. sp. (male); B. pristirana n. sp. (male); B. stridulator n. sp. (male), and B. valdivia n. sp. (female). Photographs of the type specimens of: Bolostromus fauna (male and female); Bolostromus gaujoni (male); B. holguinensis (female juvenile); B. insularis (female juvenile); B. pulchripes (female); B. riveti (male) and, B. venustus (female) are provided, as well as a distribution map of all species.

Envenomation caused by venomous animals may trigger significant local complications such as pain, edema, localized hemorrhage, and tissue necrosis, in addition to complications such as dermonecrosis, myonecrosis, and even amputations. This systematic review aims to evaluate scientific evidence on therapies used to target local effects caused by envenomation. The PubMed, MEDLINE, and LILACS databases were used to perform a literature search on the topic. The review was based on studies that cited procedures performed on local injuries following envenomation with the aim of being an adjuvant therapeutic strategy. The literature regarding local treatments used following envenomation reports the use of several alternative methods and/or therapies. The venomous animals found in the search were snakes (82.05%), insects (2.56%), spiders (2.56%), scorpions (2.56%), and others (jellyfish, centipede, sea urchin-10.26%). In regard to the treatments, the use of tourniquets, corticosteroids, antihistamines, and cryotherapy is questionable, as well as the use of plants and oils. Low-intensity lasers stand out as a possible therapeutic tool for these injuries. Local complications can progress to serious conditions and may result in physical disabilities and sequelae. This study compiled information on adjuvant therapeutic measures and underscores the importance of more robust scientific evidence for recommendations that act on local effects together with the antivenom.

The gnaphosid spider genus Sidydrassus Esyunin & Tuneva, 2002 is currently known to contain only three species: S. shumakovi (Spassky, 1934) (♂♀, the type species), S. tianschanicus (Hu & Wu, 1989) (♂♀) and S. rogue Tuneva, 2004 (♂). A revision of new material has revealed one more species, S. saiynovi sp. n. (♂) from Kazakhstan. Furthermore, the previously unknown female of S. rogue is described. The redescriptions and new faunistic records of S. shumakovi and S. tianschanicus are provided as well, and the known distribution of the genus is mapped. The defining key to Sidydrassus species is provided and possible relationships within the genus are briefly discussed.

We revise the Portuguese spiders of the genus Harpactea Bristowe, 1939 (Araneae: Dysderidae). The following seven new species are described: H. adicensis sp. nov., H. crespoi sp. nov., H. dolanskyi sp. nov., H. henriquesi sp. nov., H. korenkoi sp. nov., H. krejcii sp. nov. and H. pekari sp. nov. In three species, H. algarvensis Ferrández, 1990, H. minoccii Ferrández, 1982 and H. tavirensis Wunderlich, 2020 the females are described for the first time. The Portuguese Harpactea spiders belong to two species groups, namely the hombergi group and the corticalis group (sensu Deeleman-Reinhold 1993). The majority of the Portuguese representatives of the corticalis group probably constitute a monophyletic group endemic for the Iberian peninsula, the minoccii subgroup Ferrández, 1990. The synapomorphy of this clade is the unique position of partners during copulation: the male grasps one of the female\'s chelicerae between his chelicerae. The males\' chelicerae are morphologically adapted for this behaviour. Due to this unusual position during copulation the female genitalia are more distant from the male than in other Harpactea species. Therefore, the pedipalps are more elongated . Furthermore, the males of this subgroup possess larger basal part of male copulatory organ (the tegulum), where the ejaculate is stored before copulation. We observed that the males of this subgroup invest significantly more time into single copulation than the other representatives of the corticalis group with smaller tegulum. Therefore, enlargement of the tegulum might reflect different sperm competition strategy, in which males invest more ejaculate in each copulation. In Portugal, Harpactea spiders are frequently found under woody plants that produce slowly decomposing leaf litter, usually Quercus spp., or introduced Eucalyptus sp. These spiders require slightly humid substratum.

Three new species of the agelenid spider genus Bifidocoelotes Wang, 2002 are described from the mainland of China: Bifidocoelotes elongatus sp. nov. (♀; Guangxi, south China), B. mammiformis sp. nov. (♀, ♂; Guangdong, south China) and B. quadratus sp. nov. (♀; Guangxi, south China). The generic diagnosis is revised, and with the discovery of the three new species, the number of species in Bifidocoelotes doubles to six. Descriptions and illustrations of the three new species, a key to all the six species, and a distribution map for the genus are provided.

The formation of extraembryonic membranes (EEMs) contributes to the proper development of many animals. In arthropods, the formation and function of EEMs have been studied best in insects. Regarding the development of extraembryonic tissue in chelicerates (spiders and relatives), most information is available for spiders (Araneae). Especially two populations of cells have been considered to represent EEMs in spiders. The first of these potential EEMs develops shortly after egg deposition, opposite to a radially symmetrical germ disc that forms in one hemisphere of the egg and encloses the yolk. The second tissue, which has been described as being extraembryonic is the so-called dorsal field, which is required to cover the dorsal part of the developing spider germ rudiment before proper dorsal closure. In this review, we summarize the current knowledge regarding the formation of potential extraembryonic structures in the Chelicerata. We describe the early embryogenesis of spiders and other chelicerates, with a special focus on the formation of the potential extraembryonic tissues. This article is part of the theme issue \'Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom\'.