Chersaecia magna (Gude, 1897) Páll-Gergely, Barna, 2018

Páll-Gergely, Barna, 2018, Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae), European Journal of Taxonomy 455, pp. 1-114 : 42-44

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.3818778

persistent identifier

https://treatment.plazi.org/id/03CC87A0-6C05-8A0C-FDEB-FA8F4430FACC

treatment provided by

Valdenar

scientific name

Chersaecia magna (Gude, 1897)
status

comb. nov.

Chersaecia magna (Gude, 1897) View in CoL comb. nov.

Figs 5 View Fig E–F, 20A–B, 21A–D

Plectopylis magna Gude, 1897 View in CoL h: 70, fig. 52a–f [“ Burma ”].

Plectopylis lissochlamys Gude, 1897 View in CoL h: 70–71, fig. 53a–f [“ Burma ”]. Syn. nov.

Plectopylis magna View in CoL – Gude 1898h: 9–11, fig. 7a–f; 1900b: 91.

Plectopylis lissochlamys View in CoL – Gude 1898h: 11–13, fig. 8a–f.

Plectopylis (Plectopylis) magna View in CoL – Gude 1899d: 148; 1899e: 175; 1914b: 122–124, fig. 60a–f. Plectopylis (Plectopylis) lissochlamys View in CoL – Gude 1899d: 148; 1899e: 175; 1914b: 121–122, fig. 59a–f.

Diagnosis

A medium-sized to large, flat species with two lamellae on the parietal wall, and a main plica free from the apertural fold; palatal wall with typical Plectopylis -like plicae.

Material examined

Types

MYANMAR: 1 shell, holotype of lissochlamys (D = 19 mm), Burma ( NHMUK 1922.8.29.38); 1 shell, holotype of magna (D = 25.4 mm), Burma ( NHMUK 1922.8.29.37).

Additional material

MYANMAR: 1 shell (“ magna ”), Burma, Mergui, coll. Bosch ex Rolle ( SMF 172064); 2 shells (“ lissochlamys ”), Moulmein, coll. Möllendorff ( SMF 150098); 1 shell (“ lissochlamys ”), Burma ( NHMUK 1899.4.22.77); 2 shells (“ magna ”), Tuonghoo, coll. Godwin-Austen ex Blanford ( NHMUK 1923.2.15.5); 2 shells (“ magna ”), Burma, Tonghu, Theobald leg., coll. Blanford ( NHMUK 1906.1.1.731); 1 shell (“ magna ”), Burma ( NHMUK 1899.4.22.78).

LOCALITY UNKNOWN: 2 shells, coll. H.E.J. Biggs, Acc. no. 2258 ( NHMUK).

Description

SHELL. Sinistral, large, thick, pale greyish-yellowish to brown, flat, only protoconch protruding slightly above dorsal surface; protoconch consists of 2.5–2.75 whorls, extremely finely granular and rather regularly, roughly ribbed, rib strength and density increases towards the end of protoconch; suture of protoconch shallow; whorls 7.25–7.5, teleoconch whorls separated by deep suture; teleoconch with rather irregular, dense, fine ribs and only fine striation; body whorl has a much weaker sculpture, ventral side nearly smooth, glossy; body whorl rounded; aperture oval; peristome whitish, expanded and reflected; parietal callus as strongly developed as peristome, rather sharp, slightly S-shaped; apertural fold free from parietal callus, very long, its end visible in oblique view into aperture; umbilicus wide, shallow, funnel-shaped.

The holotypes of Plectopylis magna and P. lissochlamys had been opened. Parietal wall with two lamellae; posterior lamella longer, slender, both ends elongated posteriorly; anterior lamella wider, slightly oblique to shell axis; lower end equally elongated both anteriorly and posteriorly, upper end elongated slightly in posterior direction, with a slightly longer elongation (= short main plica) anteriorly; lower plica slender, reaches peristome. Palatal wall with six main plicae; first situated close to upper suture, long, slightly curved; second plica strongly elongated anteriorly, straight; third short, curved; fourth and fifth join to form a vertical plate; sixth curved, of normal length, situated near lower suture; small denticles visible at posterior ends of all plicae; holotype of P. magna with an additional short horizontal plica between first and second plica.

MEASUREMENTS (in mm). D = 22.1–25.4, H = 7.9–8.9 (holotype of magna , and two other shells); D = 16, H = 6.7 (holotype of lissochlamys ).

Differential diagnosis

Chersaecia leucochila is smaller, has a more elevated spire, a deeper and narrower umbilicus, and its main plica is in contact with the apertural fold. See also under C. feddeni .

Distribution

This species is known from the country of Myanmar only, although the exact type locality is unknown.

Remarks

The holotype of Plectopylis magna differs from that of P. lissochlamys by the larger size, the longer anteriorly elongated lower part of the anterior lamella and the stronger lower plica, which is clearly visible only under the lamellae in P. lissochlamys , but continues only as a slight indication until the peristome in P. magna . All of these characters could be interpreted as intraspecific variability. Therefore, P. lissochlamys is assigned as a synonym of P. magna .

NHMUK

Natural History Museum, London

SMF

Forschungsinstitut und Natur-Museum Senckenberg

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Stylommatophora

Family

Plectopylidae

Genus

Chersaecia

Loc

Chersaecia magna (Gude, 1897)

Páll-Gergely, Barna 2018
2018
Loc

Plectopylis (Plectopylis) magna

Gude G. K. 1914: 122
Gude G. K. 1914: 121
Gude G. K. 1899: 148
Gude G. K. 1899: 175
Gude G. K. 1899: 148
Gude G. K. 1899: 175
1899
Loc

Plectopylis magna

Gude G. K. 1898: 9
1898
Loc

Plectopylis lissochlamys

Gude G. K. 1898: 11
1898
Loc

Plectopylis magna

Plectopylis magna Gude, 1897 h: 70
Loc

Plectopylis lissochlamys

Plectopylis lissochlamys Gude, 1897 h: 70–71
GBIF Dataset (for parent article) Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF