Stephanopis ditissima (Nicolet, 1874)

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 : 292-293

“ditissima clade ”

The relationship between Stephanopis species from the Andean region and Coenypha was well supported by molecular evidence (Wheeler et al. 2017) and corroborated by morphologic studies ( Machado et al. 2017). Although preliminary, the insights and results obtained by Machado et al. (2017) regarding the topology of the clade remained consistent in comparison to what we found in the present work ( Fig. 2 ). According to Machado et al. (2017), the coincident geographical distribution and several similarities regarding the morphology of copulatory structures of these species could indicate possible synonymies or new combinations between the two genera. The inclusion of two more species of Stephanopis from the Andean region in our data matrix aimed to test if those previous hypotheses could be corroborated through broader morphological comparisons. The disposition and shape of copulatory structures in Coenypha , such as the wide median septum, exposed copulatory ducts, acute RTA, laminar embolus and abdominal projections laterally disposed, are remarkably similar to what are observed in S. ditissima , Stephanopis nodosa (Nicolet, 1849) and St. antennata Tullgren, 1902 . The node gathering these “Andean Stephanopis ” in a clade with Coenypha is shown to be stable, being recovered under all weighting schemes and Bayesian analysis ( Fig. 2 ), and here called “ ditissima clade”. The group with four species presented significant branch supports ( Fig. 3 ), being recovered by five homoplastic characters ( Fig. 6 ) and corroborating previous evidences based on morphological ( Machado et al. 2017) and molecular data (Wheeler et al. 2017). Therefore, consider that the Stephanopis species belonging to the “ ditissima clade” should be transferred to Coenypha ( Fig. 6 ).

The close relationship between Coenypha and the “Neotropical Sidymella ” was similarly obtained in Wheeler et al. (2017). Additionally, our findings show these two sister clades being related to the entire “ Epicadus group”. The Coenypha + “Neotropical Sidymella ” relationship was recovered not only by the presence of membranous and hyaline copulatory ducts of the female genitalia (Char. 88, state 1) but also by males bearing a flattened and laminar embolus (Char. 107, state 1; see Fig. 8 (3)f) resting on tegulum (Char. 112, state 1).

Figures

Fig. 2 Hypothetical reconstruction of the relationships of Stephanopis and Sidymella based on the strict consensus of the most congruent tree (K = 17.89) obtained after implied weighted analysis. Nodal stability is represented by the “Navajo rugs” along the branches (analysis recovering

Fig. 3 Clade supports obtained by relative Bremer index (above the branches) and symmetric resampling analysis (below the branches). A colour scheme is applied to represent the geographical distribution of the clades represented on the working phylogenetic hypothesis

Fig. 6 Character transformations, detailed topology of the relationships between “ditissima clade” (blue) and Sidymella (stricto sensu); emergence of the “pentacantha clade” (purple) as part of the “Epicadus group”

Fig. 8 Characters relative to dorsal habitus and prosoma of specimens sampled in the present analysis: a Stephanopis lata, frontal view. b Sidymella excavata, frontal view. c Stephanopis pentacanha, carapace. d Epicadinus trispinosus, carapace. e Tmarus polyandrus, carapace. f Isala arenata comb. nov., dorsal habitus. g Epicadus granulatus, sternum. h Borboropactus nyerere, sternum