Palaina Semper, 1865

Hausdorf, Bernhard, 2017, Revision of the Diplommatinidae (Gastropoda: Cyclophoroidea) from Java, Zootaxa 4312 (2), pp. 201-245 : 235

Palaina Semper, 1865

Palaina Semper, 1865: 291 , 292. Type SpecieS (SubSequently deSignated by Iredale, 1944: 303): Diplommatina macgillivrayi Pfeiffer, 1854 .

Diagnosis. Palaina is characterized by the lack of palatal folds (rarely with a low radial plaque), a parietal lamella and a columellar lamella (rarely with a weakly developed columellar lamella), a lack of aperture distortion and a multispiral operculum with an arcuate ridge on the inner surface and usually with a spiral ridge on the outer surface.

Remarks. Palaina in the traditional sense proved to be paraphyletic in molecular phylogenies ( Rundell 2008; Webster et al. 2012). Yamazaki et al. (2013) redefined Palaina based on characters of the shell and the operculum. However, they confirmed that the traditional delimitation of this genus from Diplommatina based on the absence of a columellar lamella remains still useful in most cases except that a weakly developed columellar lamella may be visible in the aperture of some Palaina species. Yamazaki et al. (2013) stressed especially the presence of an arcuate ridge on the inner surface of the operculum. However, we found such a ridge not only in Palaina ( Fig. 6 ), but also in Diplommatina javana ( Fig. 4 ), which can hardly be classified in Palaina as currently delimited because of its prominent columellar lamella and the presence of palatal folds. A spiral ridge on the outer surface of the operculum is present in P. gedeana ( Fig. 6 ), but is hardly developed in P. nubigena ( Fig. 7 ).

Figures

FIGURES 4 – 8. Opercula of Diplommatinidae. 4. Diplommatina javana Möllendorff, 1897, outer and inner Surface of opercula, WeSt JaVa: Majalengka, Argamukti, Mt. Ciremai National Park (MZB 13261). 5. Diplommatina auriculata Möllendorff, 1897, inner Surface of operculum, WeSt JaVa: Majalengka, Argamukti, Mt. Ciremai National Park (MZB 13258). 6. Palaina gedeana Möllendorff, 1897, outer and inner Surface of opercula, WeSt JaVa: Majalengka, Argamukti, Mt. Ciremai National Park (MZB 13244). 7. Palaina nubigena Möllendorff, 1897, outer Surface of operculum, WeSt JaVa: Cianjur, Kandang Badak (ZMA 68468). 8. Arinia yanseni n. sp., inner Surface of operculum, EaSt JaVa: Rembang, Sumber PacuSen (MZB 18882). Scale bar = 0.07 mm for FigS 3 – 6, 0.1 mm for Fig. 7.