Sidymella lobata, Machado & Teixeira, 2021

Machado, Miguel & Teixeira, Renato Augusto, 2021, Phylogenetic relationships in Stephanopinae: systematics of Stephanopis and Sidymella based on morphological characters (Araneae: Thomisidae), Organisms Diversity & Evolution (New York, N. Y.) 21 (2), pp. 281-313 : 293

publication ID	https://doi.org/ 10.1007/s13127-020-00472-x
persistent identifier	https://treatment.plazi.org/id/576D8791-FFE8-FFA8-FF7C-1D54FAFFFC12
treatment provided by	Felipe
scientific name	Sidymella lobata
status

Treatment

Sidymella View in CoL

According to the diagnosis provided by Machado et al. (2019a), Sidymella and Coenypha have a series of similar characteristics related to the epigynum and the male palp. This view is correct if only the Neotropical species of Sidymella are being considered in such a comparison. The Australian representatives of the genus, although presenting some features common to the Neotropical species, such as the presence of spiniform macrosetae on the mesial surface of femora I (interpreted here as dorsolateral setiferous tubercles) (Char. 49, state 1; see Fig. 14a and b View Fig ) and epigynum with accessory glandular heads (Char. 90, state 1; see Fig. 8 View Fig (0)g), emerged in four different clades ( Fig. 2 View Fig ). The evidence obtain- ed through our data also suggest that the bifid opisthosoma, a character that was still being recently considered by Machado et al. (2019a) as valid way to recognize and distinguish Sidymella from other stephanopines, in fact appeared in 11 different groups. Thus, contrary to what previous taxonomic works have shown ( Lise 1973; Machado et al. 2019a), the presence of dorsolateral humps on the abdomen of these spiders seems to be insufficient to undoubtedly characterize the genus. Moreover, the composition of Sidymella as a natural group is implausible if we consider that this and other somatic characters shared between Neotropical and Australian species of Sidymella as the result of a possible adaptive convergence to support the same hunting behaviour. These spiders are commonly found on tree branches and plant stems with their forelegs close together and directed frontwards, camouflaging themselves as twigs (pers. obs.). The polyphyletic emergence of Sidymella , as currently circumscribed, is corroborated by molecular evidence presented by Wheeler et al. (2017). Similar to our results, the findings presented by these authors recover the Neotropical species of Sidymella as sister group to Coenypha ( Fig. 6 View Fig ) while Australian species are related to Stephanopis (here, represented by the emergence of St. barbipes + St. lobata comb. nov.) ( Fig. 7 View Fig ). Although visibly distinct regarding their somatic features, the palpal architecture of Sidymella species from the Australian region is similar to those of Stephanopis by presenting CP (Char. 116, state 1; see Fig. 18h View Fig ), filiform embolus (Char. 107, state 0; see Fig. 18h View Fig ) and the RTA acute (Char. 103, state 1; see Fig. 18h View Fig ) with grooved surface (Char. 104, state 1).

The group composed by Si. lucida and five other species of Sidymella recorded in the Neotropical region (World Spider Catalog 2020) was recovered with good stability ( Fig. 2 View Fig ). The clade also presented significant branch supports ( Fig. 3 View Fig ), being sustained by two synapomorphies that set them apart from Australian species: RTA with nodose texture (Char. 104, state 2; see Fig. 19b View Fig ) and tegulum with scaled surface (Char. 110, state 1; see Fig. 20d View Fig ). Thereby, although we call this group the “lucida clade” throughout the discussion, we anticipate that this is the only clade that should truly be considered as Sidymella (stricto sensu). Australian species currently attributed to this genus are hereinafter treated as “dissident” clades, which should be proposed as new genera in future taxonomic works ( Fig. 7 View Fig ).