Pseudostegodera Wu & Chen, 2021

Chen, Zhe-Yu, Lyu, Zhi-Tong & Wu, Min, 2021, Systematic revision of Stegodera Martens, 1876 (Gastropoda, Stylommatophora, Camaenidae), with description of a new genus, ZooKeys 1059, pp. 1-21 : 1

Pseudostegodera Wu & Chen gen. nov.

Type species.

Pseudostegodera qiului gen. et sp. nov.

Diagnosis.

Shell sinistral. Apical whorls with dense fine ribs gradually becoming granules. The last 1/8 to 1/4 body whorl compressed, only partly covering penultimate whorl. Umbilicus broad. Head wart absent. Each side of mantle edge with a leaf-shaped appendage. Penis sheath present. Penis externally simple. Epiphallic papilla absent. Flagellum present. Dart sac apparatus absent.

Remarks.

Conchologically the new genus can be distinguished from Stegodera by the detached body whorl and penultimate whorl. The new genus is supported to be the closest relative of a clade containing Stegodera + Nesiohelix as based on the Maximum Likelihood/Baysian Inference phylogeny shown in Fig. 1A . However, when the Australian camaenids were included in the analysis, the relationships between the new genus, Stegodera + Nesiohelix , and all remaining taxa except Satsuma remained unresolved (Fig. 1B ). The new genus is conchologically similar to Stegodera , however, it differs in certain reproductive characters (see above). We consider that the genital anatomy is more informative than shell features in helicoid systematics (e.g., Criscione and Köhler 2013). In addition, the loss of the dart sac apparatus in Bradybaeninae and/or Camaeninae is not a frequent event during the evolution of Camaenidae (Fig. 1B ). Based on these two considerations, we consider it is reasonable to distinguish this new camaenid taxon as a monotypic genus represented by the new species described below.

Figures

Figure 1. Bayesian Inferences of camaenids (representatives of genera in Table 1) based on partial mitochondrial 16 S and CO 1 sequences. Numbers near nodes indicate Bayesian posterior probabilities. The squares on the right of each taxon name indicate its character states. Abbreviations: PS: penial sheath; EpP: epiphallic papilla; PC: penial caecum; Fl: flagellum; DS: dart sac apparatus A phylogram without Australian camaenids B the results of ancestral states (tagged on branch in red, blue, or black) reconstruction mapping on the phylogram with some Australian camaenid genera added. Orange part: the topologies supported by the results respectively by using both Bayesian Inference and Maximum Likelihood methods. Character states are from Schileyko (2003) and Wu (2019). Scale bars for substitutions per site.