The distribution, spatial clustering, and density of trapdoor spiders in two California coastal dune ecosystems

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  The distribution, spatial clustering, and density of trapdoor spiders in two California coastal dune ecosystems Abstract Coastal dune ecosystems support endemic trapdoor spiders, yet population data for these species are limited. We conducted the first coastal dune trapdoor spider population estimation surveys at Moss Landing State Beach (California) and for Aptostichus stephencolberti Bond 2008 at Sunset State Beach using randomly selected 1m 2 quadrats across ~26,000 m 2 per site. Burrow densities were similar between sites (Sunset: 0.287 burrows/m 2 ; Moss: 0.453 burrows/m 2 ), yielding estimated population sizes of ~35,206 and ~30,959 individuals, respectively. However, spatial analyses revealed contrasting patterns of burrow distribution. At Sunset State Beach, burrow presence was strongly associated with vegetation and occurred closer to plants, despite vegetation being randomly distributed. In contrast, no vegetation–burrow association was detected at Moss Landing, alth...

Phylogenetic classification of poorly known Crassignatha spiders (Araneae, Symphytognathidae), with descriptions of four new species

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Phylogenetic classification of poorly known Crassignatha spiders (Araneae, Symphytognathidae), with descriptions of four new species

Abstract

The genus Crassignatha Wunderlich, 1995, represents the second most species-rich lineage within the spider family Symphytognathidae. Members of the genus are predominantly distributed in southwestern China and Southeast Asia, with the exception of C.kishidai (Shinkai, 2009), which is recorded from Japan. Historically, the circumscription and diagnosis of Crassignatha have remained ambiguous, and its monophyly has not yet been rigorously tested. In this study, we conducted a molecular phylogenetic analysis based on sequence data from five genetic markers (16S, 18S, 28S, H3, and a fragment of COI) to evaluate the monophyletic status of the genus. Sequences were obtained from 21 species of Crassignatha (ingroup), along with two species of Kirinua Li & Lin, 2021, and one species of Patu Marples, 1951, as the outgroup. The results support the monophyly of Crassignatha and confirm the taxonomic validity of the 21 included species. Five species of Crassignatha belonging to Symphytognathidae are reported from the Yunnan–Guizhou Plateau, four of which are newly described: C. hekou Wu & Lin, sp. nov. (♂♀), C. qingxu Wu & Lin, sp. nov. (♂♀), C. liangdu Wu & Lin, sp. nov. (♂♀), and C. panlong Wu & Lin, sp. nov. (♂♀). Additionally, a new distribution record outside the type locality is provided for the previously known species C. shunani Lin & S. Q. Li, 2020 (♂♀). Detailed diagnoses, descriptions, and illustrations are provided for all newly described species. The geographic distribution of Crassignatha is also discussed.

Wu H, Lin Y (2026) Phylogenetic classification of poorly known Crassignatha spiders (Araneae, Symphytognathidae), with descriptions of four new species. Zoosystematics and Evolution 102(1): 159-179. https://doi.org/10.3897/zse.102.165834