Macrobrachium cavernicola (Kemp, 1924)

Kharkongor, Ilona Jacinta, Saikia, Uttam, Khynriam, Dimos & Saikia, Bhaskar, 2023, Current status of faunal diversity of Siju Cave, South Garo Hills, Meghalaya, Records of the Zoological Survey of India 123 (3), pp. 283-303 : 293

22. Macrobrachium cavernicola (Kemp, 1924)

1924. Palaemon cavernicola Kemp, Rec. Ind. Mus. XXVI , p. 42, pl. iii, Figs.1-4 .

Material examined: 6 ex. Siju Cave (~ 1000m inside the Cave), Siju village, South Garo Hills District , Meghalaya, 25 o 21.061’N, 90 o 41.006’E, 119m, 19.iii.2019, coll. Uttam Saikia & party, Reg. No. IV /CRU/ERS-533 ; 4 ex. Siju Cave (~ 1200-1500m inside the Cave), Siju village, South Garo Hills District , Meghalaya, 25 o 21.061’N, 90 o 41.006’E, 119m, 4.i.2020, coll. I. J. Kharkongor & party, Reg. No.IV / CRU/ERS-596 .

Remarks: Kemp (1924) remarked that the species occurs from 550ft to ‘ nearly three-quarters of a mile from the mouth ’ of Siju Cave. Besides the main cave passage, the specimens were “ found abundantly in small streams at depths of 2000 to 3600 ft. and in practically all the still pools in the section between 2200 and 3000 ft. Several were discovered in isolated pot-holes little more than 2 ½ ft. broad ”. During the resurvey of the Cave, we observed that the species can be found only in the deeper parts of the Cave (~ 1200m from the entrance and beyond) and their numbers have dwindled immensely from that reported in 1924. Macrobrachium cavernicola is an important component of the cavernicolous fauna of Meghalaya and is reported to be found in most of the river caves of the State. The species shows marked troglomorphism and is, so far, the only known troglobytic shrimp in India. The species is probably endemic to the karstic region of Meghalaya.

Figures

Figure 1. Map of Siju Cave showing the explored parts. (Courtesy: Meghalaya Adventurers’ Association, Shillong).

Figure 2. The cave entrance of Siju.