von notho2 am 21.04.2022, 16:51 ISSN 0738-9388
Bertia setzeri, a New Species of Land Snail from Vietnam(Gastropoda: Stylommatophora: Dyakiidae)
Author
Nguyen Ngoc Thach
Ex-Research Associate, Oceanographic Institute, Nha Trang, Vietnam
Figure 1. Images1-4: Bertia sertzeri n.sp., Khánh Hòa, Vietnam, Holotype 78.6 mm wide, Image No. 4 shows sculpture at penultimate whorl with many granules, ANSP; Images 5-8: Bertia cambojiensis, Syntype at NHMUK for comparison; Images 9-12: Bertia pergrandis, Syntype at NHMUK for comparison; Images 13-16: Bertia brookei for comparison, Image Nos. 13, 14 and 16 by
Bernard Dupont, Image No. 15 by Reeve; Images 17-20: Bertia sertzeri n.sp., Paratype, 75mm wide, with animal when alive, Image No. 19 shows internal organs of the snail, NNT
ABSTRACT
A new species of genus Bertia Ancey, 1887 is described from Khánh Hòa, Central Vietnam and compared to three species of this genus: Bertia cambojiensis (Reeve, 1860), Bertia pergrandis (Smith, 1893) and Bertia brookei (Adams & Reeve, 1848).
INTRODUCTION
Bertia is a genus of the family Dyakiidae. At the end of 2014, an unknown land snail was found that was not included in the works by Schileyko (2011). It belongs to the genus Bertia and is described herein.
Abbreviations
ANSP = Academy of Natural Sciences, Philadelphia, USA NHMUK = National Museum of Natural History, London, England NNT = Collection N.N.Thach
SYSTEMATICS
Class Gastropoda Cuvier, 1797
Order Stylomatophora Schmidt, 1855
Family: Dyakiidae Gude & Woodward, 1921
Genus: Bertia Ancey, 1887
Type species: Helix cambojiensis Reeve, 1860
Bertia setzeri n. sp.
Figure 1, Images 1-4 and 17-20
Diagnosis
The new species is characterized by completely black base with the shell width much larger than its height.
Description
Shell large (70-75 mm in average adult size, reaching 78.6 mm in width) heliciform sinistral much wider than high with 5.5 whorls. Spire low and inflated, sutures deep. Body whorl swollen, periphery rounded with a moderately strong spiral rib. Sculpture consists of many broad radial ribs at body whorl (each rib is a series of 3-4 riblets) and numerous small granules formed by intersections of fine radial and spiral ribs at penultimate whorl. Aperture wide obliquely ovate and and bluish at upper
part with external pattern visible within and darker at lower part, outer lip wide thin and not angulated. Base inflated, strongly convex and sculptured with numerous radial ribs. Umbilicus broad open and deep, periostracum thin and straw-colored. Color red-brown at dorsal side and completely black at ventral side. Illustrated
holotype was damaged at periphery.
Type material
Holotype 78.6 mm wide in ANSP (Fig.1, Images 1-4). Paratype 1: 75 mm wide in NNT (Fig. 1, Images 17-20). Paratype 2: 73.8 mm wide and Paratype 3: 76.2 mm wide in Ex-NNT (not illustrated).
Type locality
At the border of Khánh Vĩnh District and Nha Trang outskirts, Khánh Hòa Province, Central Vietnam.
