The redescription of Corynethrix obscura L. Koch, 1876 (Araneae: Thomisidae)—a crab spider of a monotypic genus from Australia

Corynethrix obscura L. Koch, 1876 from Peak Downs, Queensland, Australia is redescribed and fully illustrated. The representatives of this species are characterized by small size, a body covered with clavate and spatulate setae and a distinctive pattern on the dorsum of the opisthosoma. The paper includes taxonomic remarks on three genera within the subfamily Bominae. Szymkowiak, Pawel, and agnieSzka dymek, 2011. The redescription of Corynethrix obscura L. Koch, 1876 (Araneae: Thomisidae)—a crab spider of a monotypic genus from Australia. Records of the Australian Museum 63(1): 99–102. The crab spiders of Australia remain a taxon that has been insufficiently investigated. For the majority of Australian species there are no revisionary studies that would allow species identification. Most of the available descriptions originate from the end of the 19th century and, since then, no studies have analysed type material. As a consequence, available information is frequently incomplete and unreliable. Corynethrix obscura was described in 1876 by Ludwik Koch, on the basis of one female. A male is still unknown. The original description lacked many morphological details and was poorly illustrated. So vague is the description, that almost any species of the three known genera of the subfamily Bominae (Thomisidae) might be misidentified. Another species was described by Simon: Corynethrix tuberculata Simon, 1886. This species was subsequently excluded from the genus Corynethrix and made the type species of Boliscus Thorell, 1891 (Simon, 1895). Therefore Corynethrix Koch, 1876 is monotypic with C. obscura as the type species. Little is known of the biology and behaviour of this crab spider (Hawkeswood, 2003). Material and methods All measurements were performed using the Olympus SZX12 microscope with magnification of 11–144×. The photos were taken using an Artcam 500 MI camera and Quick Photo Camera 2.3 software. Black and white images were prepared using pencil and Rotring ink pens: 0.25 mm and 0.5 mm. The following abbreviations and symbols are used: AMS, Australian Museum, Sydney; AME, anterior median eye; ALE, anterior lateral eye; MOA, median ocular area delineated by anterior median eyes AME and posterior median eyes PME; PLE, posterior lateral eye; PME, posterior median eye; VTA, ventral tibial apophysis of male palp; x/y, ratio of the distance between PLE=PLE and distance between L–R (distance between left and right margins of cephalothorax on the line running through PLE); ZMH, Museum of Zoology, Hamburg, Germany. In order to obtain new specimens for taxonomic study, the coll ec tions of crab spiders of the Australian Museum, Sydney, and the Queensland Museum, Brisbane, were 100 Records of the Australian Museum (2011) Vol. 63 Figs. 1–5. Corynethrix obscura (1) habitus; (2) prosoma, front view; (3) right palp; (4) the seta of the left palp; (5) labium, maxillae and sternum. Scale bars for 1, 2 and 5 are 1000 μm; for 3 is 50 μm, and for 4 is 100 μm. studied. Most specimens identified as Corynethrix sp. were, in fact, a variety of Bomis species. The only available juvenile individual of C. obscura was immediately recognized because of a very characteristic abdominal pattern and the morphology of its prosoma. Schick (1965) described the morphology of the dorsum of the prosoma. Corynethrix obscura L. Koch, 1876