Endothyrella minor (Godwin-Austen, 1879)

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 : 31-32

Taxon classification Animalia Pulmonata Plectopylidae

Endothyrella minor (Godwin-Austen, 1879) Figure 23 E–F

Endothyrella minor 1870 Helix (Plectopylis) macromphalus var. minor , - W. Blanford, Journal of the Asiatic Society of Bengal, 39 (2): 18. (no formal description presented) ["in valle Rungnu prope Darjiling in Sikkim"].

Endothyrella minor 1879b Helix (Plectopylis) minor Godwin-Austen: The Annals and Magazine of Natural History, 5 (4): 164.

Endothyrella minor 1895 Helix (Plectopylis) minor , - Godwin-Austen: Journal of the Asiatic Society of Bengal, 64: 154, Plate 7, figs 3, 3a.

Endothyrella minor 1897c Plectopylis minor , - Gude: Science gossip, 4: 11, figs 47 a–k.

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

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

Endothyrella minor 1914b Plectopylis (Endothyra) minor (partim), - Gude: The Fauna of British India …: 73, 75-77, figs 27 a–l. ["Sikkim: Darjeeling", "Rungun Valley", "India: Naga Hills", "Laisen Peak, Munipur" (this is the locality of Endothyrella robustistriata sp. n.)].

Endothyrella minor 2015 Endothyrella minor , - Budha et al., ZooKeys, 492: 18-19.

Types.

Darjiling, leg. Stoliczka, coll. Godwin-Austen, NHMUK 1903.07.01.768/10 syntypes. See also remarks.

Additional material examined.

Nepal, Lalitpur, Phulchowki Hill, 2308 m, 27.574557°N, 85.400842°E, leg. Budha, P., 04.05.2007., 21 shells (Figure 23F); Nepal, Kathmandu, Chisapani, Shivapuri-Nagarjun National Park, 2361 m, 27.804855°N, 85.436468°E, leg. Budha, P., 11.06.2007., 5 shells; Nepal, Golphubhanjyan, Langtang National Park, Rasuwa, 3340 m, 27.873931°N, 85.757744°E, leg. Budha, P., 10.06.2007., 1 shell; Nepal, Shivapuri-Nagarjun National Park, Deurali, Baghdwar, 2386 m, 27.798318°N, 85.385448°E, leg. Budha, P., 25.04.2008., 1 shell; Nepal, Shivapuri-Nagarjun National Park, Shivapuri Peak, 2707 m, 27.810987°N, 85.383763°E, leg. Budha, P., 24.04.2008., 1 shell; India, Darjiling, leg. Stoliczka, coll. Oberwimmer, NHMW 71640/O/6881 (4 shells); Darjeeling, coll. Rolle, NHMW 71770/R/11 (3 shells); Darjiling, coll. Dr. Stoliczka, 1880, NHMW 91587/20; Darjeeling, coll. Möllendorff, SMF 150112/2; Darjeeling, coll. Webb, SMF 150111/2; Khasi Hills, NHMUK 20150159/3; Sikhim, Rarhichu, NHMUK 20150158/6 (mixed sample with Endothyrella blanda ); India, Darjeeling, coll. Oldham, NHMUK 20150160/5; India, 1879.12.26.172-177/5; Sikhim, NHMUK 1906.2.2.361/3; Darjeeling, NHMUK 20150161/1 (there is a number “751” on the bottom); Sikkim, NHMUK 1888.12.4.1525(?) (1 specimen); Darjeeling, under stones, 7000', coll. Everest Expedition 9 and 18.03.1924, NHMUK 20150162/5; Khasi Berge, SMF 345110/3 (ex Endothyrella macromphalus , SMF 150102); Toruputu Pk., Dafla Hills, NHMUK 1903.07.01.769/4 (mixed sample with Endothyrella macromphalus ); Darjiling, coll. Hungerford ex coll. Nevill, NHMUK 1891.3.17.358-359 (Figure 23E).

Diagnosis.

Shell tiny, sinistral, with relatively narrow umbilicus, flat dorsal surface and four rows of hairs; callus strong; palatal plicae divided; lamella straight or slightly curved, with two denticles posteriorly, one above and one below; lower plica can be short and in some specimens reaching the peristome.

Measurements

(in mm): D: 4.9-5.3, H: 2.4-2.6 (n = 3, type series); D: 5-5.1, H: 2.4 (n = 3, SMF 345110); D: 4-5, H: 2-2.5, Wh: 5-5.5 (n = 12, Nepalese specimens).

Differential diagnosis.

Endothyrella minor is smaller and has weaker keeled body whorl than Endothyrella angulata sp. n. Moreover, the first and second rows of the periostracal folds are comparatively at larger distance from each other in Endothyrella minor than in Endothyrella angulata sp. n. Endothyrella blanda has more elevated spire and more hair rows than Endothyrella minor . Endothyrella robustistriata sp. n. has more elevate spire than Endothyrella minor and lacks the hairs on its ventral surface. Endothyrella macromphalus is hairless and larger than Endothyrella minor , it has a comparatively larger protoconch and a lower (or missing) parietal callus. Endothyrella minor is smaller and flatter than Endothyrella dolakhaensis sp. n. Moreover, it has a more elevated parietal callus, and has only four rows of hairs ( Endothyrella dolakhaensis sp. n. has five). See also under Endothyrella williamsoni and Table 5.

Distribution.

Originally the species was recorded from Darjeeling, Sikkim area. Very similar specimens were found from Central Nepal in the surroundings of Kathmandu (Shivapuri-Nagarjun National Park and Phulchowki hill) and Langtang National Park. Some literature records (Laisen Peak, Naga Hills) are based on misidentified specimens (see Figure 11 and 15).

Remarks.

W. Blanford (1870) described Helix (Plectopylis) macromphalus , and while giving information on its locality, he mentioned that "varietas minor" inhabits the Rungun valley near Darjeeling. No description or illustration of "varietas minor" was provided in the paper, therefore the name is not available. Later, Godwin-Austen (1879b) described Helix (Plectopylis) minor from "Darjiling hills" and mentioned those shell "no doubt are referable to Plectopylis macromphalus W. Blf., var. minor ". Blanford’s specimens labelled as macromphalus minor have not been found in the collection of the NHM, but the type sample examined and described by Godwin-Austen (NHMUK 1903.07.01.768) was found.

Recent fieldwork in Nepal yielded a few populations in the surroundings of Kathmandu which can be assigned to Endothyrella minor . “Typical” specimens of Endothyrella minor and Nepalese shells are very similar in terms of size, shell and aperture shape and the morphology of the plicae and lamellae. The only notable difference between these shells is the position of the hair rows on the body whorl. The first row is situated more upper in position (on the upper angle of the body whorl) in the Nepalese shells, whereas in typical shells the first row runs under the angle. Additionally, the distance between the third and fourth rows is smaller in the Nepalese populations.