Messageria sinica, Chen & Lin, 2021

Chen, Zhe-Yu & Lin, Li-Wen, 2021, Notes on the genus Messageria Bavay & Dautzenberg, 1904, with descriptions of a new speciesand anew subspecies (Gastropoda: Caenogastropoda: Cyclophoroidea Alycaeidae), Zootaxa 5067 (1), pp. 129-134 : 132

Messageria sinica Z.-Y. Chen & L.-W. Lin, n. sp.

Figures 1I–O , 2B

Holotype: HBUMM 10021 , Botanical Garden of Shishang Forest Scenic spot, Maolan National Nature Reserve , Maolan Town , Libo County, Buyi and Miao Autonomous Prefecture of QianNan , Guizhou. 2019.VI. 16. 780m. leg. Lu QIU . Paratype: HBUMM 10055 (one juvenile), Maolan National Nature Reserve, Maolan Town , Libo County, Buyi and Miao Autonomous Prefecture of QianNan , Guizhou. 2021. V. 21. 780m. leg. Yan SUN .

Etymology. This name commemorates the first discovery of this genus in China.

Description. Shell small (<5 mm), dextral, roundly conical, about 5.5 whorls. Shell translucent, relatively glossy, apical part light orange. Apex slightly convex, apical whorls depressed conical. Basal whorls ovoid. Protoconch oblique compared to shell axis, 1.25 whorls with matte surface. The next 0.5 whorl of the teleoconch with regularly spaced and equally high, weak ribs. The other whorls have well-spaced, high and thin main ribs, with a distinctly lower intermediate rib in between each pair of main ribs, ca. 9 (main and intermediate) ribs per 1 mm on body whorl. The intercostal distance increases with the whorls, and the strength (height) of the two kinds of ribs becomes same at umbilical area. Umbilicus deep.Aperture rounded, slightly oblique. Peristome double, with prominent outer peristome. Inner peristome protruding, with parietal callous thick; outer peristome expanded but not reflected. Operculum rounded, corneous, concave; outer surface with multispiral lamina; inner surface simple, glossy.

Measurements. H = 3.62 mm, W = 3.20 mm, D A = 1.95 mm (holotype).

Diagnosis. Compared to Messageria scalarioides , the new species is distinguished by the much more distinct lower intermediate ribs in between each pair of high ribs, particularly on the outer whorls of the shell. Additionally, M. scalarioides has moderately convex apex and nearly conical basal whorls, which are slightly convex and ovoid in the new species. The 1/8 whorl behind the aperture of M. sinica n. sp. grows evenly, while it is expanded in M. scalarioides (especially in M. scalarioides donghiana n. ssp.).

Vernacular name. 中华Ħfiḏ zhōng huá chóng lèi luó

Distribution. CHINA: Guizhou.

Figures

FIGURE 1. Species of Messageria (A–M) and Helicomorpha (P–S). A–D. Messageria scalarioides (syntype, MNHN-IM- 2000-32414). E–H. Messageria scalarioides donghiana n. ssp. (holotype, HBUMM 10058) I–O. Messageria sinica n. sp. I–L. (holotype, HBUMM 10021). M. (paratype, HBUMM 10055). N–O. Opercula, outer side (N) and inner side (O) (holotype, HBUMM 10021) P–S. Helicomorpha turricula (lectotype, SMF 105304). Photos: Barna Páll-Gergely (A–D), Zhe-Yu Chen (E–O) and Sigrid Hof (P–S).

FIGURE 2. Protoconch of Messageria Bavay & Dautzenberg, 1904. A. Messageria scalarioides donghiana n. ssp. (holotype, HBUMM 10058) B. Messageria sinica n. sp. (holotype, HBUMM 10021) Photos: Zhe-Yu Chen.