Sidymella hirsuta (L. Koch, 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 : 294

publication ID

https://doi.org/ 10.1007/s13127-020-00472-x

persistent identifier

https://treatment.plazi.org/id/576D8791-FFE9-FFA9-FF7C-1D9EFAE5FDC6

treatment provided by

Felipe

scientific name

Sidymella hirsuta
status

 

“hirsuta View in CoL clade ”

The “ hirsuta clade” is formed by spiders that resemble Epicadinus by their “spiny” habitus, with long and needle-shaped setae covering their entire prosoma (Char. 11, state 0 and 2), opisthosoma (Char. 80, state 1; see Fig. 21h View Fig ) and legs. The group was supported by 10 homoplastic characters and one synapomorphy: RTAvbr spoon-shaped(Char. 106, state 3; see Fig. 19e View Fig ). Because of how the characters were treated in our analyses, this ambiguous feature was not shown along the branch on the working phylogenetic hypothesis. Nevertheless, the emergence of the genus by itself is held by strong branch supports ( Fig. 3 View Fig ) and good nodal stability ( Fig. 2 View Fig ). As observed in Stephanopis , the male palp architecture of species of the “ hirsuta clade” is characterized by the presence of a RTAvbr, well-developed CP, oval-shaped tegulum and filiform embolus meandering at its distal portion (whip-like). The arrangement and shape of copulatory structures of females, although slightly different from those of Stephanopis , also show some degree of resemblance. Females of the “ hirsuta clade” have flattened, narrowed and tubular copulatory ducts (Char. 86, state 0; Fig. 16e, g View Fig ) and spermathecae significantly longer than those of Stephanopis . Despite having an opisthosoma with a pair of “protruding corners” (dorsolateral projections), a feature considered by Koch (1874) to justify the original description of Si. hirsuta in Sidymella , other somatic characters (e.g. number and arrangement of tibial and metatarsal macrosetae; disposition of teeth of the tarsal claws) wildly differ from those of the species type of this genus. The relationship of the “ hirsuta clade” with the clade composed of the “ Epicadus group” and ( Coenypha + Sidymella ) was based on three highly homoplastic characters, each presenting numerous state reversals. Moreover, both Bremer indexes and symmetric resampling analyses presented low support values for this more inclusive clade ( Fig. 3 View Fig ) as well as sensitivity analyses showing weak nodal stability in this section of the topology ( Fig. 2 View Fig ). Such results, along with the unpredictable behaviour of the clade, suggest that the placement of the “ hirsuta clade” is particularly arguable. Similarities and shared characters between this group and Stephanopis , in addition to their coincident geographical distribution, must also be considered as evidence that the placement of the “ hirsuta clade” with most Neotropical stephanopine genera sampled in this study is questionable and most likely to be spurious.

Kingdom

Animalia

Phylum

Arthropoda

Class

Arachnida

Order

Araneae

Family

Thomisidae

Genus

Sidymella

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