Endothyrella pinacis (Benson, 1859)

Pall-Gergely, Barna, Budha, Prem B., Naggs, Fred, Backeljau, Thierry & Asami, Takahiro, 2015, Review of the genus Endothyrella Zilch, 1960 with description of five new species (Gastropoda, Pulmonata, Plectopylidae), ZooKeys 529, pp. 1-70 : 36-37

Taxon classification Animalia Pulmonata Plectopylidae

Endothyrella pinacis (Benson, 1859) Figures 24 D–F

Endothyrella pinacis 1859 Helix pinacis Benson: The Annals and Magazine of Natural History, 3 (3): 268-269. ["Habitat raro in regione Sikkim in valle Rungun (4000 ped.), necnon prope Pankabari (1000 ped. alt.)"].

Endothyrella pinacis 1860 Helix (Plectopylis) pinacis , - Benson: The Annals and Magazine of Natural History, 3 (5): 243-247. ["Darjiling and the Khasia Hills"].

Endothyrella pinacis 1868 Helix pinacis , - Pfeiffer: Monographia Heliceorum Viventium …, 5: 417.

Endothyrella pinacis 1868 Helix (Corilla) pettos Martens: Malakozoologische Blätter, 15: 158.

Endothyrella pinacis 1869 Helix pettos , - Pfeiffer: Novitates conchologicae …: 462-463.

Endothyrella pinacis 1872 Helix pinacis , - Hanley & Theobald: Conchologia Indica …: 7, 36, Plate 13, fig. 5, Plate 84, figs 1-4. ["Sikkim (Rungun, and near Pankabari)"].

Endothyrella pinacis 1875 Plectopylis pettos , - Godwin-Austen: Proceedings of the Zoological Society of London, 612. [ “Himalaya?”].

Endothyrella pinacis 1875 Helix (Plectopylis) pinacis , - Godwin-Austen: Proceedings of the Zoological Society of London: 612, 613, plate 74, fig. 1. (1874, part IV, published in 1875; see Duncan 1937).

Endothyrella pinacis 1878 Helix (Plectopylis) pinacis , - Nevill: Hand list of Mollusca in the Indian Museum …: 71.

Endothyrella pinacis 1879b Helix (Plectopylis) pinacis , - Godwin-Austen: The Annals and Magazine of Natural History, 5 (4): 163.

Endothyrella pinacis 1887 Helix (Atopa) pettos , - Tryon: Manual of Conchology …, 2 (3): 156, Plate 34, figs 36-38.

Endothyrella pinacis 1887 Helix (Plectopylis) pinacis , - Tryon: Manual of Conchology …2(3)159– 160, Plate 34, figs 53-55.

Endothyrella pinacis 1894 Plectopylis pinacis , - Pilsbry: Manual of Conchology..., 2 (9): 144, 146.

Endothyrella pinacis 1894 Plectopylis pettos , - Pilsbry: Manual of Conchology..., 2 (9): 146.

Endothyrella pinacis 1895 Plectopylis pinacis , - Godwin-Austen: Journal of the Asiatic Society of Bengal, 64: 154, Plate 7, figs 2, 2a.

Endothyrella pinacis 1897a Plectopylis pinacis , - Gude: Science Gossip, 3: 206, figs 32 a–d.

Endothyrella pinacis 1897a Helix (Corilla) pettos = Plectopylis pinacis , - Gude: Science Gossip, 3: 206.

Endothyrella pinacis 1899c Plectopylis (Endothyra) pinacis , - Gude: Science Gossip, 6: 147, 148.

Endothyrella pinacis 1899c Plectopylis (Endothyra) pettos (under pinacis ), - Gude: Science Gossip, 6: 148.

Endothyrella pinacis 1899d Plectopylis (Endothyra) pinacis , - Gude: Science Gossip, 6: 175, 177.

Endothyrella pinacis 1899d pettos , - Gude: Science Gossip, 6: 177.

Endothyrella pinacis 1907 Plectopylis pinacis , - Godwin-Austen: Land and freshwater Mollusca of India …: 203-204.

Endothyrella pinacis 1914b Plectopylis (Endothyra) pinacis , - Gude: The Fauna of British India …, 72, 86-87, figs 35 a–d. ["Sikkim: Darjeeling", "Rungun, Pankabari", “Rungmaval”, “Damsang”].

Endothyrella pinacis 1914b Plectopylis (Endothyra) pinacis , - Gude: The Fauna of British India …: 72, 86.

Endothyrella pinacis 1915 Plectopylis (Endothyra) pinacis , - Gude: Records of the Indian Museum, 8: 506, 508.

Types.

Sikkim, coll. Benson, UMZC 102755 (holotype of Helix pinacis , Figure 24D); Himalaya, ZMB/MOLL 17905 (holotype of Helix pettos , Figure 24E).

Additional material examined.

India, West Bengal, Darjeeling District, Lopchu + Ghum, coll. Topál, 21-22.04.1967, locality code: 869, HNHM 98848/2; Darjiling, coll. Dr. Stoliczka, 1880, NHMW 92590/7; Sikkim, coll. Möllendorff, SMF 150110/6 (3 of them juvenile); Darjeeling, coll. Bosch, ex coll. Rolle, SMF 172075/2; Darjiling, figured in Godwin-Austen (1874), coll. Godwin-Austen, NHMUK 1903.7.1.746/5; Darjiling, coll. W. Blanford, NHMUK 1860.6.27.14 (1 specimen); Kungna valy. (?) Sikm., NHMUK 20150163/2; Darjiling, NHMUK 1906.2.2.143/2 (Figure 24F); Damsang Peak, Daling Hills, coll. Godwin-Austen, NHMUK 20150164/26 (several of the juvenile); Sikkim, Rarhichu, NHMUK 20150165/5; Rechila Peak, coll. Godwin-Austen, NHMUK20150167/1; Darjiling, NHMUK 1888.12.4.1524/1; Darjeeling, 5000', coll. Everest Expedition 1924, NHMUK 20150168/1; Rarkichu, Sikkim, coll. Godwin-Austen, NHMUK 20150166/1.

Diagnosis.

Shell very small to small, sinistral, hairless, with wide umbilicus and slightly angulated body whorl; callus strong, palatal plicae short and oblique, lamella rather straight with anteriorly elongated upper and lower ends, and posteriorly elongated upper end; there are two denticles on the posterior side of the lamella, one above and one below, the lower one might be in contact with the lamella.

Measurements

(in mm): D: 13.6-14.1, H: 5.9-6.1 (n = 3, SMF 150110).

Differential diagnosis.

Endothyrella angulata sp. n. is usually smaller than Endothyrella pinacis , it has a stronger keel and has weaker spiral lines on the ventral side of the shell, which are clearly visible in Endothyrella pinacis . The most similar species is Endothyrella nepalica sp. n., which nevertheless has a higher spire and rounded whorls, whereas Endothyrella pinacis has shouldered whorls and nearly flat dorsal surface. The ventral surface of the two species is similar, but Endothyrella pinacis has slender hairs standing in 3 lines, which is missing in Endothyrella nepalica sp. n. According to previous studies ( Godwin-Austen 1889-1914, Schileyko 1999) Endothyrella pinacis has no diverticulum, but in all Endothyrella nepalica sp. n. we dissected that organ was present. Endothyrella oakesi is similar to Endothyrella pinacis , but has much more complicated palatal plicae, more descending aperture, differently shaped umbilicus and rounded body whorl. See also Table 5.

Anatomy.

The anatomy of Endothyrella pinacis was described by Godwin-Austen (1889-1914) and Schileyko (1999). According to these descriptions, only the gametolytic sac is present and the diverticulum is missing. The penial caecum seems to be missing, although none of these drawings show this part clearly. Other features of the genitalia (penis shape, internal wall of the penis, vagina) are similar to those of Endothyrella nepalica sp. n.

Radula.

Stoliczka (1871) mentioned that the central tooth is larger than that of Plectopylis achatina (= bensoni ), and that its shape is similar to that of the laterals. Godwin-Austen (1889-1914) gave an accurate description and drawings of the teeth. According to his drawings the morphology of the teeth of Endothyrella pinacis is typical for the genus Endothyrella , i.e. the central tooth is larger than the ectocones of the first laterals, and the marginals are tricuspid with deep incisions between the two innermost cusps.

Distribution.

All museum samples examined were collected from Sikkim. Benson’s (1860) locality in the Khasi Hills is probably incorrect (Figure 11).