Chersaecia brachyplecta ( Benson, 1863 ), 2018

Páll-Gergely, Barna, 2018, Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae), European Journal of Taxonomy 455, pp. 1-114 : 17-18

publication ID	https://doi.org/10.5852/ejt.2018.455
publication LSID	lsid:zoobank.org:pub:C445E95B-446A-4601-AAA3-C1CCBAB627F9
DOI	https://doi.org/10.5281/zenodo.3818746
persistent identifier	https://treatment.plazi.org/id/03CC87A0-6C3C-8A36-FE1B-FECB4492FAF0
treatment provided by	Valdenar (2020-05-08 18:45:36, last updated 2025-02-20 12:21:53)
scientific name	Chersaecia brachyplecta ( Benson, 1863 )
status	comb. nov.

Treatment

Chersaecia brachyplecta ( Benson, 1863) View in CoL comb. nov.

Figs 6 View Fig C–D, 7I–J

Helix (Plectopylis) brachyplecta Benson, 1863: 319 [“ad ripas fluvii Attaran prope Moulmein”].

Helix brachyplecta – Pfeiffer 1868: 396–397.

Helix (Plectopylis) brachyplecta – Hanley & Theobald 1872: 26, pl. 57, figs 7, 10. — Godwin-Austen 1875b: 613, pl. 74, fig. 8–8a. — Nevill 1878: 72. — Tryon 1887: 163, pl. 35, figs 76–77, 82–83.

Plectopylis brachyplecta View in CoL – Gude 1897b: 246, fig. 37a–f.

Plectopylis (Endoplon) brachyplecta View in CoL – Gude 1899d: 148; 1899e: 175; 1914b: 117–119, fig. 57a–f; 1920: 62.

Diagnosis

A large, dextral, robust, flat species (protoconch elevated) with two lamellae and a long main plica extending to the parietal callus.

Material examined

Syntype MYANMAR: 1 shell, “Ad ripas fluvii Attaran prope Moulmein”, coll. Benson ( NHMUK 1954.6.2.282).

Additional material MYANMAR: 1 shell, Moulmein ( NHMUK); 2 shells (figured in Godwin-Austen 1875b), Moulmein, Tenasserim, coll. Godwin-Austen ( NHMUK 1903.7.1.749).

Description

SHELL. Dextral, robust, flat, brownish, although the available specimens are largely eroded; protoconch large, consists of 3.5 whorls, matt, finely, densely, irregularly wrinkled; whorls 6–6.25 (n = 2), separated by deep suture; teleoconch finely, irregularly wrinkled; dorsal side with some reticulated sculpture, ventral surface smoother; aperture with widened sinulus; peristome strongly thickened and slightly reflected; parietal callus low, blunt, slightly S-shaped; apertural fold very long, connected to parietal callus.

One opened shell was observed. Parietal wall with two lamellae, upper end of anterior lamella curves anteriorly, whereas lower end slightly elongated in both anterior and posterior directions; posterior lamella slightly reversed S-shaped. The shell fragment having the palatal plicae was attached to the shell, but was somewhat damaged, therefore only 5 plicae were visible; all middle plicae oblique and depressed Z-shaped, or wavy; the last plica horizontal, straight.

MEASUREMENTS (in mm). D = 21.5–21.7, H = 7.6–7.8 (n = 2, type series).

Differential diagnosis

Chersaecia smithiana is larger, has a shallower umbilicus, a stronger and sharper parietal callus and, most importantly, only a single lamella.

Distribution

Chersaecia brachyplecta is known from the type locality only.

References

Benson W. H. 1860. Notes on Plectopylis, a group a Helicidae distinguished by several internal plicate Ephiphragms; with the Characters of a new Species. The Annals and Magazine of Natural History 3 (5): 243 - 247. Available from https: // biodiversitylibrary. org / page / 18658580 [accessed 30 Jul. 2018].

Benson W. H. 1863. Characters of new Land-Shells from the Andaman Islands, Burmah, and Ceylon, and of the Animal of Sophina. The Annals and Magazine of Natural History 3 (11): 318 - 323. Available from https: // biodiversitylibrary. org / page / 22221772 [accessed 30 Jul. 2018].

Godwin-Austen H. H. 1875 b. Descriptions of five new Species of Helicidae of the Subgenus Plectopylis, with remarks on all the other known forms. Proceedings of the Zoological Society of London 1874: 608 - 613. Available from https: // biodiversitylibrary. org / page / 28502797 [accessed 30 Jul. 2018].

Gude G. K. 1897 b. Armature of Helicoid landshells. Science Gossip 3 (33): 244 - 246. Available from https: // biodiversitylibrary. org / page / 33878864 [accessed 30 Jul. 2018].

Gude G. K. 1899 d. Armature of Helicoid landshells and new sections of Plectopylis. Science Gossip 6 (65): 147 - 149. Available from https: // biodiversitylibrary. org / page / 34012981 [accessed 30 Jul. 2018].

Gude G. K. 1899 e. Armature of Helicoid landshells. Science Gossip 6 (66): 174 - 177. Available from https: // biodiversitylibrary. org / page / 34123273 [accessed 30 Jul. 2018].

Gude G. K. 1914 b. The Fauna of British India including Ceylon and Burma. Mollusca. ‾ II. (Trochomorphidae- - Janellidae). Taylor & Francis, London. Available from https: // biodiversitylibrary. org / page / 12910698 [accessed 30 Jul. 2018].

Nevill G. 1878. Hand list of Mollusca in the Indian Museum, Calcutta. Part I. Gastropoda. Pulmonata and Prosobranchia-Neurobranchia. Order of the Trustees, Calcutta. Available from https: // biodiversitylibrary. org / page / 19872326 [accessed 30 Jul. 2018].

Pfeiffer L. 1868. Monographia Heliceorum Viventium: Sistens Descriptiones Systematicas et Criticas Omnium Huius Familiae Generum et Specierum Hodie Cognitarum. Brockhaus, Leipzig. Available from https: // biodiversitylibrary. org / page / 12932069 [accessed 30 Jul. 2018].

Tryon G. W. 1887. Manual of Conchology; Structural and Systematic. With Illustrations of the Species. Ser. 2, vol. 3. Helicidae, Volume I. Published by the Author, Philadelphia. Available from https: // biodiversitylibrary. org / page / 1287540 [accessed 30 Jul. 2018].

Figures

Fig. 6. Shells and protoconchs of Chersaecia Gude, 1899. A–B. C. austeni (Gude, 1899), lectotype (NHMUK 1903.06.01.1014.1). C–D. C. brachyplecta (Benson, 1863) comb. nov., syntype (NHMUK 1954.6.2.282). E–F. C. smithiana (Gude, 1897) comb. nov., syntype (NHMUK 1888.12.4.1555). Scale bars: A, C, E = 10 mm; B, D, F = 2 mm. All photos: H. Taylor.