Cybella, Judson, Mark L. I., 2017

Judson, Mark L. I., 2017, A new subfamily of Feaellidae (Arachnida, Chelonethi, Feaelloidea) from Southeast Asia, Zootaxa 4258 (1), pp. 1-33 : 5

Cybella n. gen.

Diagnosis. As for the subfamily (monogeneric).

Etymology. Feminine diminutive, derived from Cybele, Greek goddess of mountains, caves and wild animals, who was often depicted with a turret-like crown on her head.

Type species. Cybella deharvengi n. sp.

Distribution. Southeast Asia: limestone hills of southern Cambodia and southern Vietnam.

Remarks. Cybella shows most of the derived features that characterize the family Feaellidae , including the raptorial form of the palps, the unusual trichobothriotaxy, the separation of the chelal teeth into more than one row, the presence of two anteromedian projections on the carapace, the modified form of the articulation between the carapace and tergite I, and the presence of thickened chemosensory setae on the movable chelal finger. At the same time, it shares some plesiomorphic features with Pseudogarypidae , such as the absence of well defined pleural plates, the presence of two blades in the rallum, the tubular form of the spinneret, and the apodens of each chelal finger still recognizable (as opposed to being in a terminal cluster of indistinguishable teeth). Cybella can therefore be considered the sister-group of all other extant Feaellidae . To emphasize the differences between the two groups, Cybella is here placed in its own subfamily, Cybellinae, while Feaella and Iporangella are placed in Feaellinae. Monophyly of Feaellinae is supported by the synapomorphic reduction of the rallum to one blade or none, a bladeshaped spinneret, the presence of well-defined plural plates bearing lyrifissures and the clustering of teeth at the end of the movable finger, amongst which the apodens can no longer be easily recognized.

The poor development of the pleural plates in Cybellinae is of particular interest. In Feaellinae, there are two rows of plates—one dorsal and one ventral—running along the pleural membranes on each side of the opisthosoma. These plates are fully sclerotized, with a reticulate sculpturing, and bear setae, gland pores and lyrifissures. They therefore resemble miniature versions of the tergites and sternites. Although setae, gland pores and lyrifissures are all present on the dorsal and ventral folds of the pleurum of Cybellinae, they are not grouped together in the same way. As discussed below, the absence of pleural plates in Cybellinae is considered to be plesiomorphic.