Evolution and escalation, an ecological history of life

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Predation in the marine fossil record: Studies, data, recognition, environmental factors, and behavior

http://www.iiserkol.ac.in/~devapriya/Chattopadhyay%20%26%20Dutta,%202013.pdf

Prey selection by drilling predators: A case study from Miocene of Kutch, India

Naticid drilling predation on gastropod assemblages across the K–T boundary in Rajahmundry, India: New evidence for escalation hypothesis

Predation is an important process in modern oceans and in the evolutionary history of marine ecosystems. Consequently, it has been hypothesized that shelled prey modified their ornamentation in response to predation. However, bivalve ornamentation has also been argued to be important in maintaining a stable life position in the sediment and in burrowing. To test whether concentric ribs were effective against drilling by carnivorous gastropods, we examined drill hole position and completeness for four Cenozoic bivalve species that differ in rib strength (Astarte radiata, A. goldfussi, Lirophora glyptocyma, and L. latilirata). The percentage of drill holes located between the ribs increases with increasing rib strength, whereas the percentage of drill holes on top of ribs decreases. This result suggests that gastropods select the drill hole site more effectively as rib strength increases, thereby saving time and energy, and that natural selection favors gastropods that select drill hole sites betwe...

/pdf/shell-ornamentation-as-a-likely-exaptation-evidence-from-1qa0x21era.pdf

Shell ornamentation as a likely exaptation: evidence from predatory drilling on Cenozoic bivalves

Fossilized shell assemblages are often the result of postmortem transportation. It is therefore crucial to identify biases introduced due to differences in the hydrodynamic properties of shells to ensure the validity of ecological interpretations. In a flow tank study with the bivalve Donax scortum Linnaeus, 1758, we found that shell size, shape, and ornamentation played an important role in dictating the hydrodynamic properties of shells. This study demonstrates that threshold current velocity for the entrainment of a convex-up shell is generally determined by its size, a result corroborating previous findings. We found that a smaller shell is mobilized with a lower velocity compared to a larger one. Additionally, we found ornamentation of a shell also played a significant role in transportation. Unlike previous studies, we have demonstrated that altered smooth shells require a higher velocity for transportation compared to fresh shells with pronounced ornamentation. The movement trajectory of a shell depends on its asymmetry. The right and left valves of a single individual are deflected in distinctly different directions. This study shows that the extent of such deflection is dependent on the size of the valve and the velocity of the flow. Using a simulation based on our experimental data, we have also demonstrated the effect that transportation bias can have in modifying a shell assemblage. The results of this study underscore the concept that the final distribution of shells following a transportation event may yield a bivalve population significantly different from the original one.

http://www.iiserkol.ac.in/~devapriya/Chattopadhyay%20et%20al,%202013.pdf

The effect of morphology on postmortem transportation of bivalves and its taphonomic implications

Traces of predation by drilling gastropods and peeling crabs provide important insights about predator-prey interaction in ecological as well as evolutionary times. Predation on turritelline gastropods, in this context, has been frequently discussed in literature. Here, we have estimated the intensity of predation (both drilling and peeling) on Recent turritelline gastropods from the Indian subcontinent, which has been underrepresented in previous studies. Our samples include our own collections from several Indian coasts as well as a vast collection which was locked in the archive of the Zoological Survey of India (ZSI) in Kolkata for the past 150 years. It includes samples from different parts of the Indian subcontinent as well as from many other countries. Drilling frequency (DF) of Indian turritelline species is low compared to average values of global data. We suggest that this is mainly because most of the Indian species are larger (> 4 cm) than species living elsewhere. Smaller species show higher DF and lower values of peeling frequency. Size selectivity of drill holes shows both intra- and interspecific variation. Shell thickness and ornamentation appear to be antipredatory in nature.We have compared our results with a revised global database. Distribution of intensity of predation shows latitudinal variation where both drilling and peeling frequencies increase towards the tropics.

https://bioone.org/journals/malacologia/volume-56/issue-1&2/040.056.0211/Predation-on-Recent-Turritelline-Gastropods-from-the-Indian-Subcontinent-and/10.4002/040.056.0211.pdf

Predation on Recent Turritelline Gastropods from the Indian Subcontinent and Comparison with a Revised Global Database

Although common, confamilial naticid predation intensity was not very high in the geological record. Here, we gathered modern confamilial predation data from the Indian coasts and showed that confamilial naticid predation on a naticid species, Natica gualteriana, is exceptionally high at Chandipur, one of our studied areas. We studied the different aspects of confamilial predation from the Indian coasts and showed that the predators in Chandipur were highly efficient as evident from high drilling frequency (DF), site stereotypy and low prey effectiveness. Unusually high DF on N. gualteriana may be attributed to its new arrival in Chandipur where it faced competitive elimination through predation by sympatric naticid predators. Reports of failed invasion are rare. Natica gualteriana is a small invader and therefore its invasion success is threatened by resident populations of large species that extensively drill on young individuals of N. gualteriana just to break the bottleneck of their own offspring from...

A note on exceptionally high confamilial naticid drilling frequency on Natica gualteriana from the Indian subcontinent

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 ...

https://bioone.org/journals/malacologia/volume-59/issue-2/040.059.0207/Predation-on-Recent-Terebrid-Gastropods-from-the-Indian-Subcontinent-and/10.4002/040.059.0207.pdf

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

A review of the secondary literature on the way nationalist thought in colonial India conceived ‘woman’ shows three broad strands. One is the perspective of the history of art, which studies the genealogy of the iconic symbolisation of women. The remaining stands have similar objects of knowledge (the nationalist representation of women in terms of the debi) but differ in their foci of attention. The first is concerned with the (role of the) woman in nationalist thought and how ‘real’ women had responded to that construction. The other focuses on the processes of nation building in the colony to reach its gendered aspects. We finally make a case for a synthesis of these through a few instances.

Anirban Das

Papers

The effect of morphology on postmortem transportation of bivalves and its taphonomic implications

Predation on Recent Turritelline Gastropods from the Indian Subcontinent and Comparison with a Revised Global Database

A note on exceptionally high confamilial naticid drilling frequency on Natica gualteriana from the Indian subcontinent

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

The Desired ‘One’: Thinking the Woman in the Nation