Pachylabra nevilliana Annandale & Prashad, 1921

Tripathy, Basudev, Sajan, Sheikh & Cowie, Robert H., 2019, Illustrated catalogue of types of Ampullariidae Gray, 1824 (Mollusca, Gastropoda) in the National Zoological Collection of the Zoological Survey of India, with lectotype designations, Zoosystematics and Evolution 96 (1), pp. 1-23 : 1

Pachylabra nevilliana Annandale & Prashad, 1921 Figs 9 , 15A

Pachylabra nevilliana Annandale & Prashad, 1921. Rec. Ind. Mus. 22 (1): 11-12.

Current taxonomic status.

Pila nevilliana (Annandale & Prashad, 1921), valid species.

Type locality.

"Tranquebar, which is on the east coast of Southern India" [= Tharangambadi, Nagapattinam district, Tamil Nadu, India]; Captain Lewis, leg. (Asiatic Society of Bengal collection).

Type material.

Holotype (original designation): NZSI M.11864/2 (registered 8 December 1920). Paratypes: NZSI M.25078/5 (registered 13 September 2001, 5 spms), 2 or 3 additional specimens noted by ( Nevill 1877: 5, 1885: 4), location unknown.

Shell dimensions.

Holotype: SH 36.1 mm, SW 34.3 mm, AH 27.9 mm, AW 19.6 mm, OH 25.6 mm, OW 16.0 mm. Paratypes: SH 28.5-37.1 mm, SW 26.3-33.5 mm, AH 22.3-28.5 mm, AW 17.3-22.6 mm, OH 20.5-25.5 mm, OW 11.9-15.0 mm

Remarks.

Annandale and Prashad (1921: 12) explicitly based their description on only the specimens noted by Nevill (1877: 5) as Var. B of Ampullaria nux Reeve, 1856. However, although Nevill (1877: 5) noted eight specimens and Nevill (1885: 4) noted nine, Annandale and Prashad (1921: 12) provided measurements for only three. Nonetheless, they probably saw all Nevill’s shells, as they noted that they had "extracted the radula from one of the shells examined by Nevill, which have been in Calcutta for at least 60 years, but still in several instances contain the dried animal"; the expression "several instances" suggests that they saw more than the three for which they provided measurements. The specimen figured by Annandale and Prashad (1921: fig. 2) as the “type-shell” (= holotype) is the specimen in NZSI M.11864/2; this specimen matches the illustrations in all regards, including, the erosion/corrosion of the apex, wear of the periostracum and appearance of the operculum. Its measurements are within the likely margin of error of those given by Annandale and Prashad (1920: 12, middle column). Annandale and Prashad (1920: 11) based their description only on Nevill’s shells, either eight ( Nevill 1877: 5) or nine ( Nevill 1885: 4). They gave only a single catalogue number (11864/2) for the “Type-specimens” (plural). This lot now contains only the holotype. An additional lot, NZSI M.25078/5, labelled as paratypes contains five shells. Cowie (2015: 43) considered these as only "possible paratypes". However, further study indicates that they can indeed be considered part of the type series because 1) the dimensions of at least two of them approximate the additional dimensions given by Annandale and Prashad; 2) “Tranquebar” is written on the shells; and 3) “type” is written in the original register alongside the entry for this lot.

Figures

Figure 9. Holotype of Pachylabra nevilliana Annandale & Prashad, 1921; NZSI M. 11864 / 2.

Figure 15. Collection labels. A. Pachylabra nevilliana Annandale & Prashad, 1921; NZSI M. 11864 / 2. B. Pila robsoni Prashad, 1925; NZSI M. 2414 (holotype), NZSI M. 21546 / 4 (paratypes).