Plectopylis cyclaspis (Benson, 1859)

Páll-Gergely, Barna, 2018, Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae), European Journal of Taxonomy 455, pp. 1-114 : 91-94

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.3818828

persistent identifier

https://treatment.plazi.org/id/03CC87A0-6C76-8A7A-FDB9-FB6D4201FB47

treatment provided by

Valdenar

scientific name

Plectopylis cyclaspis (Benson, 1859)
status

 

Plectopylis cyclaspis (Benson, 1859) View in CoL

Figs 35I View Fig , 41E View Fig

Helix catinus Benson, 1859a: 185 [“prope Moulmein, provinciae Tenasserim”].

Helix cyclaspis Benson, 1859b: 273 (nom. nov. pro Helix catinus Benson, 1859 , non Helix catinus Pfeiffer, 1857: 64 ).

Helix revoluta Pfeiffer, 1867: 64 [“in insulis Andamanicis”].

Helix (Plectopylis) cyclaspis – Benson 1860: 245–246 [“Farm Caves near Moulmein”]. — Hanley & Theobald 1870: 7, pl. 13, fig. 10. — Godwin-Austen 1875b: 613, pl. 74, fig. 10. — Nevill 1878: 72. — Tryon 1887: 164–165, pl. 35, fig. 9.

Plectopylis cyclaspis View in CoL – Stoliczka 1871: 222–223, pl. 15, figs 4–6. — Gude 1897b: 244, fig. 34a–d.

Plectopylis (Plectopylis) cyclaspis View in CoL – Gude 1899d: 148; 1899e: 175; 1914b: 130–132, fig. 65a–d; 1920: 63.

Diagnosis

A medium-sized, sinistral species with brownish purple shell and very conspicuous, sharp keel.

Type material

Benson (1859a) wrote the following in the original description of Helix catinus : “The single specimen transmitted for examination is in such a corroded state, that the true nature of the sculpture can merely be guessed at.” In the type collection of the NHM there are three shells having an intact sculpture with the following data: Damalthat, NHMUK 1898.12.04.1520–22, 3 syntypes. These three shells surely do not represent type specimens of P. cyclaspis .

Material examined

MYANMAR: 3 shells, Burma, Moulmein, coll. Oldham, Pres. 1951 ( NHMUK); 2 shells, Moulmein ( NHMUK); 2 juv. shells, Moulmain, coll. Godwin-Austen ( NHMUK); 4 shells, Molmein ( NHMUK); 2 shells, Burma ( NHMUK 1871.9.23.48); 2 juv. shells, Moulmain, coll. Godwin-Austen ( NHMUK); 2 shells, Tenasserim, Moulmein, coll. Godwin-Austen, (“P.Z.S., 1874”) ( NHMUK); 4 shells, Moulmein ( NHMUK 1906.2.2.148); 2 shells, Burma, Moulmein, coll. J.S. Hawkins ( NHMUK 1954.6.2.270–271); 3 shells, Burmah, Moulmein, coll. Salisbury ex Beddome ( NHMUK).

Description

SHELL. Sinistral, strongly built, brownish purple, basal side lighter; protoconch consists of 2.75–3 whorls, matt, almost smooth or sometimes extremely finely granulated and roughly wrinkled; teleoconch irregularly wrinkled, without spiral lines; fresh shells with flat periostracal folds on keel; whorls 6.25– 6.5, strongly, sharply keeled, suture not conspicuous, an additional groove runs above suture; umbilicus narrow; aperture strongly facing downwards (in direction of ventral side); peristome conspicuously protruding in elongation of keel, which results in a concave bay between the parieto-palatal edge of peristome and the position of keel; peristome strongly thickened and reflected; parietal callus almost straight or very slightly S-shaped; apertural fold strong, free from parietal callus; umbilicus relatively narrow and deep.

Two opened shells were examined. Lambda-complex complete; left leg weak, right leg much stronger, has a very long anterior elongation; upper branch very long, parallel with upper suture; lower plica short, does not extend beyond lambda-complex; main plica absent. Palatal plicae typical of Plectopylis .

MEASUREMENTS (in mm). D = 18.9–19, H = 8.4–8.5 (NHMUK 148.06.2.2, n = 3).

CHARACTERS OF THE GENIAL STRUCTURE. Stoliczka (1871) published a description and drawings of the genitalia of this species.

RADULA. The characters of the radula of P. cyclaspis and P. bensoni (under the name achatina ) were described by Stoliczka (1871). According to him, the central tooth is very small, and the laterals have a large main cusp, and an ectocone with two or three cusps. This shape is unusual in the family Plectopylidae . Lateral teeth in all species of Plectopylis examined so far have a single large endocone, and a smaller ectocone with a single cusp. Therefore, the description of the radular teeth by Stoliczka (1871) is considered as inaccurate, probably due to insufficient instruments.

Differential diagnosis

Plectopylis cyclaspis cannot be confused with any other plectopylid species due to its conspicuous keeled whorls.

Distribution

All known samples were collected in the vicinity of Moulmein ( Myanmar). See also Remarks.

Remarks

Stoliczka (1871) claimed that the type locality of P. revoluta (Andaman Islands) is probably incorrect, because he received thousands of other shells from those islands, but none of them were plectopylids. Gude (1914b) concluded that Plectopylis revoluta ( Pfeiffer, 1867) is probably a synonym of P. cyclaspis . The species called P. revoluta in the recent literature is described here as P. malayana sp. nov.

NHMUK

Natural History Museum, London

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Stylommatophora

Family

Plectopylidae

Genus

Plectopylis

Loc

Plectopylis cyclaspis (Benson, 1859)

Páll-Gergely, Barna 2018
2018
Loc

Plectopylis (Plectopylis) cyclaspis

Gude G. K. 1914: 130
Gude G. K. 1899: 148
Gude G. K. 1899: 175
1899
Loc

Plectopylis cyclaspis

Gude G. K. 1897: 244
Stoliczka F. 1871: 222
1871
Loc

Helix revoluta

Pfeiffer L. 1867: 64
1867
Loc

Helix (Plectopylis) cyclaspis

Tryon G. W. 1887: 164
Nevill G. 1878: 72
Godwin-Austen H. H. 1875: 613
Hanley S. C. T. & Theobald W. 1870: 7
Benson W. H. 1860: 245
1860
Loc

Helix catinus

Benson W. H. 1859: 185
1859
Loc

Helix cyclaspis

Benson W. H. 1859: 273
Pfeiffer L. 1857: 64
1859
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