Stephanopis cambridgei, Thorell, 1870
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publication ID |
https://doi.org/ 10.1007/s13127-020-00472-x |
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persistent identifier |
https://treatment.plazi.org/id/576D8791-FFEE-FFAF-FCC4-1EA2FE34FE60 |
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treatment provided by |
Felipe |
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scientific name |
Stephanopis cambridgei |
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“cambridgei View in CoL clade ”
Species previously assigned to the “ cambridgei group” by Machado et al. (2019b) were recovered as a stable clade with I. punctata nested within ( Fig. 5 View Fig ). The similarities with Isala include the longitudinal dual band on the prosoma (char. 13, state 1; see Fig. 15h View Fig ), the flattened cephalic area, five ventral macrosetae on tibiae I and II (char. 13, state 1; see Fig. 15h View Fig ) in females, and the presence of modified setae on these same leg segments for males (char. 62, state 1; see Fig. 13c View Fig ). This latter character was mentioned by Machado et al. (2019b), who described it as a set of long, thin and filiform barbs. All parsimony analysis using implied weighting schemes recovered this clade ( Fig. 2 View Fig ) with relatively high support ( Fig. 3 View Fig ), with its component species presenting the granular surfaced opisthosoma (char. 78, state 2; see Fig. 13f View Fig ) as the only unambiguous synapomorphy. This group was also recovered by the presence of barbed clavate setae on their opisthosoma ( Fig. 16b View Fig ), which according to Gawryszewski (2014) are positively related to the effectiveness of becoming camouflaged through debris retention. This author found three different types of setae in St. altifrons and St. cambridgei that seem to be specialized for retaining organic particles. While St. altifrons present all three types of elongated and branched setae (generalized here as “needle-shaped”), St. cambridgei have just one, which we coded as “clavate”, while Gawryszewski (2014) describes it as cuneiform, barbed and dorsally striated. We agree with Gawryszewski (2014) that this variation in setae morphology could be related to selection for retaining different types of debris, which might indicate niche partitioning. The paraphyletic relationship between these clades can also be observed through differences in sexual traits. While males of St. altifrons have a RTAvbr and females present a shallow epigynal plate with exposed copulatory openings (char. 91, state 0; see Machado et al. (2019b), Fig. 3c and e View Fig ), the “ cambridgei group” gathers males without RTAvbr and females with well-developed folds delimiting the atrium and covering the copulatory openings (see Machado et al. 2019b, Fig. 18c View Fig ). Therefore, the morphological distinctions listed above are seen as evidence indicating that the entire “ cambridge i clade” belongs to a genus other than Stephanopis . As the taxonomy of the entire clade was recently revised by Machado et al. (2019b), we suggest here the transference of all species of the “ cambridgei group” to Isala .
Benjamin (2011) recovered St. cambridgei nested in Sidymella , having a close relationship with Si. lucida , the type species of this genus. In our results, on the other hand, St. cambridgei and other Australian species belonging to the “ cambridgei clade” have emerged as sister of a small clade of Stephanopis species with distribution restricted to Central America ( Fig. 5 View Fig ). This dichotomy, though, was weakly supported as it was recovered by only five weighting schemes in our sensitivity analysis; thus, it is probably spurious ( Fig. 2 View Fig ). Three of the five homoplasies that recover the dichotomy between these clades are based on setae morphology and its microstructures ( Fig. 5 View Fig ); however, their component species are noticeably distinct with regard to their copulatory structures (such as the absence of RTA for Stephanopis sp. 1 ) and most of its somatic characters. Moreover, under 10 implied weighting schemes, the St. championi + Stephanopis sp. 1 clade emerged independently or somehow unrelated to the “ cambridgei clade” ( Fig. 2 View Fig ).
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