3.4. Morphological analysis
The appearance of this species is characteristic: large, robust body, ovate or ellipsoidal. Usually, it is not compressed laterally. Specimens analysed were all sexually mature, and varied between 5.8 cm and 17.3 cm of length, and 4.1 cm and 9.6 cm of width. Siphons were located in the anterior part of the body; from 25 specimens only eight had siphons with different height. Ten specimens had a basal disc. The test, although hard, is usually quite thin and somewhat soft and flexible, of orange colour, brown or yellow in live specimens. In fixed specimens, the tunic was yellowish, brown or grey. Cnemidocarpa verrucosa is characterized by the presence of warts in the tunic. In this study, some specimens showed rounded and smooth warts, others presented conic with multiple spine-like ends warts, and some showed both types distributed in diverse ways on the tunic with no clear pattern, within the analysed specimens we found both types of warts. Internal characteristics represented the intraspecific variation previously described for this species: branchial sac had four folds in each side of the body, the number of longitudinal vessels in folds of the branchial sac ranged from 7 to 21, the number of longitudinal vessels between the folds of the branchial sac ranged from 1 to 5. The oral tentacles are filiform, alternating in size (short and long), the number ranged from 22 to 38. The intestine was located on the middle-ventral left side of the body, there are from 19 to 30 stomach folds. The gonads were tubular, with an enclosing membrane, and were on the mantle. Specimens showed, in general, two gonads at each side of the body, nevertheless, specimens cv12 and cv16 presented two on the right side and one on the left side, cv23 showed one gonad on each side and cv25 two gonads in the right side. The distal end with gonoducts was directed toward the atrial siphon (raw data in https://doi.org/10.1594/PANGAEA.909707).
The NMDS showed two groups among samples (Supplemental information, Fig. S1). The two groups identified in the NMDS coincided with the specimens genetically identified as group A and B in the genetic analyses. PERMANOVA revealed significant differences between the groups conformed in NMDS analysis (F = 17.17; p = 0.0001). All specimens from group B showed basal disc, while none of the specimens from group A did. Almost all individuals from genetic group A had a single type of wart, while the majority of the individuals from genetic group B had both types of warts (conical and smooth). None of the other morphological characters analysed in this study appeared to be phylogenetically informative.