Acta Arachnologica

Original Articles

Description and genome sequencing of Olios ishikawatodaorum n. sp. (Arachnida: Araneae: Sparassidae) from Aichi, Japan

Kazuharu Arakawa, Nobuo Kato, Akio Tanikawa

2025Volume 74Issue 1 Pages 1-8
Published: August 13, 2025
Released on J-STAGE: August 20, 2025

DOIhttps://doi.org/10.2476/asjaa.74.1

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A new species of Olios, O. ishikawatodaorum n. sp. (♀♂) is described from Aichi Prefecture, Japan, with its annotated genome sequence. The assembled genome spans 3.7Gbp with contig N50 length of 413.4kbp. BUSCO 5 analysis indicates high completeness of the genome (93.8% complete + 3.5% partial = 97.3%), and 22,984 genes have been predicted using RNA-Seq data as evidence. The genome sheds light on neglected RTA clade spider genomics, and reveals a number of expanded gene families in this species. Full length or near-full-length spidroin sequences obtained from the genome showed the conservation of MaSp2 which is typically lost in the RTA clade, but whose presence may explain the unusually high supercontraction and strain at break in Sparassidae spiders.

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A new species of jumping spider of the genus Noegus Simon 1900 (Araneae: Salticidae: Amycini) from Colombia

Leiner A. Suárez-Martínez, Edwin Bedoya-Roqueme, Jorge A. Quirós-Rodrí ...

2025Volume 74Issue 1 Pages 9-18
Published: August 13, 2025
Released on J-STAGE: August 20, 2025

DOIhttps://doi.org/10.2476/asjaa.74.9

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A new salticid species of the genus Noegus Simon 1900 is described herein as N. sombrerovueltiao sp. nov. (♂♀), found in the dry forest of the Córdoba department in northwestern Colombia. Photographs and illustrations of the diagnostic characters for males and females and ecological comments are provided. Distribution maps and habitat photographs are also included.

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Description of a new species of Ditha (Pseudoscorpiones: Chthoniidae) from Japan

Makoto Akiyama, Rei Ueshima

2025Volume 74Issue 1 Pages 19-25
Published: August 13, 2025
Released on J-STAGE: August 20, 2025

DOIhttps://doi.org/10.2476/asjaa.74.19

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We describe a new species of Ditha Chamberlin 1929, from Okinawa, Japan, as Ditha okinawensis n. sp. This species differs from other Ditha species in the number and position of setae at the cheliceral hand, carapace, rallum and male sternite II. Ditha ogasawarensis Sato 1981 is redescribed based on the re-examination of the type specimens and is transferred from the subgenus Ditha to Paraditha.

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Two new species of the genus Cladothela (Araneae: Gnaphosidae) from Nansei Islands, southwest Japan, with the description of the true female of C. auster

Takahide Kamura

2025Volume 74Issue 1 Pages 27-38
Published: August 13, 2025
Released on J-STAGE: August 20, 2025

DOIhttps://doi.org/10.2476/asjaa.74.27

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Examinations of spiders of the gnaphosid genus Cladothela collected from Nansei Islands, Japan revealed that two undescribed species of the genus occur in the area, and that in C. auster Kamura 1997, the previous understanding of the combination of male and female is incorrect. Two new species, Cladothela notus n. sp. and C. sakishima n. sp., and the true female of C. auster are described.

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On two species of Padillothorax Simon 1901 from Vietnam with description of the previously unknown female of its type species (Araneae: Salticidae)

Pham Thi Phuong, Tran Thi Thanh Thao, Le Thi Thu Sa, Quang Duy Hoang

2025Volume 74Issue 1 Pages 39-43
Published: August 13, 2025
Released on J-STAGE: August 20, 2025

DOIhttps://doi.org/10.2476/asjaa.74.39

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The genus Padillothorax Simon 1901 is newly recorded from Vietnam, including its type species, P. semiostrinus Simon 1901 and P. exilis (Cao & Li 2016). Additionally, P. semiostrinus is redescribed based on specimens from Vietnam and its previously unknown female is described for the first time in this study.

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A new species of the genus Cicurina Menge, 1871 (Araneae: Cicurinidae) from Hachijojima Island, Tokyo, with notes on the congeners in Japan and China

Ken-ichi Okumura, Hirotsugu Ono

2025Volume 74Issue 1 Pages 45-49
Published: August 13, 2025
Released on J-STAGE: August 20, 2025

DOIhttps://doi.org/10.2476/asjaa.74.45

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A new species of Cicurina, C. auster sp. nov. is described from Hachijojima Island, Tokyo, Japan. The morphology of the copulatory organs of the new species is similar to those of some Cicurina species known in China, while it is clearly different from all the known species from Japan. The results of a comparative examination between the new species and congeners from Japan and China are presented. A presumption about a possibility of the human introduction of the new species from the Ryukyu Islands is mentioned.

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Notoagelena silvicola, a new genus and species of the spider family Agelenidae

Akio Tanikawa, Thanakron Into, Booppa Petcharad

2025Volume 74Issue 1 Pages 51-54
Published: August 13, 2025
Released on J-STAGE: August 20, 2025

DOIhttps://doi.org/10.2476/asjaa.74.51

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Both sexes of Notoagelena silvicola new genus and species of Agelenidae are described from Western Thailand.

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