Oxytesta aborensis Godwin-Austen, 1918

Gurumayum, Shantabala Devi, 2022, A short note on rediscovering of two endemic ariophantid snails of the genus Oxytesta Zilch, 1956 after a gap of hundred years, Records of the Zoological Survey of India 122 (4), pp. 367-370 : 368

Oxytesta aborensis Godwin-Austen, 1918

1918. Oxytes aborensis Godwin-Austen, Rec. Indian Mus. , 8: 595, pl. 52.

figs 2, 2a, 2b.

Material Examined: ZSI/IV/ APRC /M-317, 1 ex. Ramsingh (28°14’05.7”N 95°13’05.1”E, 336 msl), Upper Siang district, Arunachal Pradesh, 27.10.2017, coll., G. Maheswaran, et al.,; ZSI/IV/ APRC /M-320, 5 ex. Ramsingh (28°38’41.0”N 94°59’54.0” E, 356 msl), Upper Siang district , Arunachal Pradesh, 01.12.2020.10.2017, coll., SD Gurumayum .

Shell measurements: Largest: 20mm (width), 8mm (axis); Smallest: 14mm (width), 6mm (axis)

Original type Description by Godwin-Austen: Oxytesta aborensis was described for the first time by Godwin-Austen, 1918 which was collected by Capt. Oakes during Abor expedition from between Silli and Dukku, Yamne Valley, 2000 ft.; Rotung, Shell very depressedly lenticular, more convex below than above, openly umbilicated, fragile, very sharply keeled; sculpture very finely and closely decussate, oblique to the whorl; colour rich ochraceous; spire very flatly conoid, apex flatly rounded; suture linear; whorls 6, regularly increasing; aperture oblique,semilunate,uppermarginsinuateanddescending; peristome thin; columellar margin subvertical.

Size: maj. diam. 31.25, minor 27.0, alt. axis

7.0 mm.

maj. diam. 24-0 minor 20.75 alt. axis

6-0 mm (small var. of 5 whorls).

This species (all immature) was also collected by Captain Oakes at the furthest point he reached on the Dihang R. (Siang of the Abors) near where the Siang R. joins it, and between Long. 94°55’ and 95°15’ and Lat. 29° and 29°15’. The keel is slightly compressed on both sides and the shell is duller in colour. Remarks: Oxytesta aborensis (Godwin-Austen, 1918)

is similar to O. blanfordi ( Theobald, 1859) from Darjiling, but differs by having much wider and open umbilicus and also having a finer sculpture in the Abor shells (Godwin-Austen 1918). In general form, O. aborensis is similar to O. pollux ( Theobald 1859) of the Khasi Hills but is easily distinguished from them by its open umbilicus. It is very close to O. shanensis ( Godwin-Austen, 1883) , but the shell of O. aborensis is more openly umbilicated, and sharper keeled and the sinuate margin of the peristome between suture and keel is very distinctive (Godwin-Austen, 1918; Sajan, et al., 2019). It differs from O. oxytes ( Benson, 1836) by its larger shell, less-keeled body whorl, shallow spire, and wide umbilicus.