Predation on Recent Terebrid Gastropods from the Indian Subcontinent and a Spatiotemporal Reappraisal Based on a Revised Global Database

ABSTRACT Predator-prey interaction, especially drilling and shell-breaking predation pressure, caused significant evolutionary changes within these predator-prey communities. Although temporal trends are well understood in prey assemblages, studies to trace such changes within taxonspecific clades up to Recent times have been rare. Here, we studied both the drilling and shell-breaking predation on Recent terebrid gastropods from the Indian subcontinent and compared the results with a newly updated, global database. The major part of our data came from a large collection reposited in the archive of the Zoological Survey of India in Kolkata for more than 100 years. Detailed analyses of this study based on a newly raised, global database revealed the following findings: (1) Drilling frequency (DF) of Indian terebrids was low, but consistent with the DF of only available but limited data provided by Vermeij et al. (1980). In comparison, peeling frequency (PF) in Indian terebrids appeared to be highest in the world; (2) DF showed latitudinal variation, that is, higher incidence of drilling occurred in higher latitudes; no such pattern emerged from the PF data; (3) drillholes were site-stereotyped, which suggested that Recent naticid drillers were escalated; (4) shell ornaments failed to protect against durophagy; (5) shell shape and thickness had different impact against different modes of predation. While slender and thicker shells were almost immune to drilling predation, no such relation existed for peeling predation; (6) on the other hand, body size appears to have evolved as anti-predatory traits in Recent terebrids. Larger species had low DF and high PF values; (7) temporally, DF showed fluctuating pattern, with modern values showing declining trend. This was perhaps due to increase in body size and behavioural change of the terebrid gastropods. Unfortunately, no peeling frequency data for this clade was available from the fossil record.