Morphological Variation and Speciation of Acavidae Family: A Case Study from Fossil and Living Species of Batadombalena Cave Pre-historic Site in Sri Lanka

Open access

Abstract

A sufficient knowledge on prehistoric culture and habitat of earliest Homo sapiens (Balangoda man) is available in Batadomba-lena cave, a noticeable rock shelter in lowland rainforest of southwestern Sri Lanka goes upto Pleistocene and Holocene eras. Late Pleistocene inhabitants of Batadombalena cave’s foraged for a broad spectrum of plant and mainly arboreal animal resources such as, monkeys, squirrels and rainforest snails etc. Archaeo-faunal evidence would help to describe the prehistoric man eating behavior as well as availability of nature pre-historic flora, fauna and environmental status. The family Acavidae is very sensitive to climatic variations, hence used as a bio-indicator to describe the variations of paleo-climatic nature. This study examined the morphological features of 20 samples of Acavidae family (living/fossil samples of Acavus superbus, and sub fossil samples of Oligospira waltoni) collected from soils by digger method in 2005 and compared with 20 samples from the same area at presently available. The shell characters of snails such as, height, width, diameter of mouth, thickness of lip, and angular of axis were measured and subjected to multivariate analysis to understand how climatic variability and nature of paleo-diet contribute survival of Acavidae species. Results showed that Acavus superbus living species had large shell characteristics than the sub fossils. Results of similar study in the same climatic status in 2000 showed that the shell measurements of Acavus superbus are relatively larger than both living and sub fossils in Batadobalena cave. Ordination diagram derived from species shell characteristics showed that Acavus superbus living species grouped as scattered /diffuse clusters, while sub fossil species grouped as a single cluster at the center of the ordination diagram. It is imply a trend of speciation /diversification of Acavus species from Pleistocene era to date. Multivariate analyses prove that, a strong positive correlation of species characteristics, such as height (r = 0.62), thickness of lip (r = 0.544) and angular of axis (r = 0.744), and a strong negative relationship (r = 0.832) for shell width for the species were observed. Our results are useful to compare with other fossil snails to see whether the climate change influence for changing body size. In conclusion, palaeo-environment, and present environment variation has been occurred in minimum way without much changes to observed Acavidae species compositions present and past.

REFERENCES

  • Bennington, J.B., and Bambach, R.K., (1996). Statistical testing for paleocommunity recurrence: Are similar fossil assemblages ever the same?: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 127, p. 107–133.

  • Behrensmeyer, A.K., and Hook R.W. (1992). Paleoenvironmental contexts and taphonomic models, in Behrensmeyer, A.K., Damuth, J.D., DiMichele, W.A., Potts, R., Sues, H.D., and Wing, S.L., eds., Terrestrial Ecosystems through Time: Evolutionary Paleoecology of Terrestrial Plants and Animals. University of Chicago Press, Chicago, p. 15–136.

  • Bernhard, H., and Perera, K.K. (2000). Revision of the genus Acavus from Sri Lanka (Gastropoda: Acavidae). Journal of Molluscan Studies 66.2: 217-231.

  • Brett, C.E., and Baird, G.C. (1986). Comparative taphonomy: A key to paleo environmental interpretation based on fossil preservation: PALAIOS, v. 1, p. 207–227.

  • Burnham, R.J., 1993, Reconstructing richness in the plant fossil record: PALAIOS, v. 8, p. 376–384.

  • Burnham, R.J., Johnson, K.R., and Ellis, B. (2005). Modern tropical forest taphonomy: Does high biodiversity affect paleoclimatic interpretations?: PALAIOS, v. 20, p. 439–451.

  • Connell, J.H. (1978). Diversity in tropical rainforest sand coral reefs. Science, 199: 1302-1310.

  • Connor, J.H. (1986). The role of Pleistocene forest refugia in the evolution and biogeography of tropical biotas. Trends in Ecol. and Evol. 1(6): 165-168.

  • Deraniyagala, S.U. (1992). The Prehistory of Sri Lanka: an ecological perspective. Memoir 8, 2nd ed. Archaeological Department, Colombo. 813 pp.

  • Deraniyagala, S.U. (2001). The Prehistory of Sri Lanka: an ecological perspective: Addendum1B. www.the-prehistory-of-sri-lanka.de, accessed 15 Feb.2005.

  • Deraniyagala, S.U. (2004). Prehistoric basis for the rise of civilization in Sri Lanka and Southern India. Sri Lanka Deputy High Commission in Chennai.28 pp.

  • Deraniyagala, P. E. P., (1958). The Pleistocene of Ceylon. Ceylon National Museums, Colombo. ix+164 pp., 58 pl.

  • Manamendra-Arachchi, K. R. Pethiyagoda, Dissanayake, R. & Meegaskumbura M. (2005). A second extinct big cat from the late quarternary of Sri Lanka.In:Yeo, D.C.J., K.L.Ng & R. pethiyagoda (eds.) Contribution to biodiversity exploration and research in Sri Lanka. The Raffles Bulletine of Zoology, 12: 423-434.

  • Kuruppuarachchi, K.A.J.M., Seneviratne, G. and Madurapperuma, B.D. (2016). Carbon sequestration in tropical forest stands: its control by plant, soil and climatic factors. Open Journal of Forestry, 6: 59-71.

  • Somaratne, S. and Dhanapala, A.H. (1996). Potential impacts of global climate change on forest distribution in Sri Lanka. Water, Air and Soil Pollution. 92: 129-135.

  • Sumanarathna, A.R., Pathmakumara, J., Abyewardanana, K., & Sudasinghe, A. (2015). Paleontological evidences of Pleistocene, interpret the coming of intelligence & harbor life of planet earth. International Journal of Advance Research in Science, Engineering & Technology, 2:11, 1063-1070

Journal Information

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 19 19 12
PDF Downloads 4 4 2