Carolina Loch S. Silva (PhD completed September 2013)

This page was last updated by Carolina while she conducted her PhD research at the Department of Geology, University of Otago. Find out what Carolina is doing now on our Alumni page.

Jaws and teeth of the False-killer-whale, Pseudorca crassidens (click on image to view full size (180KB)).

SEM of enamel prisms of the Pilot-whale, Globicephala sp. (click on image to view full size (1.2MB)).

Project Summary

Teeth are a valuable source of information in studies of mammalian biology, supplying data on the feeding habits, environmental influences, phylogenetic relationships among species and estimations of age. As teeth provide evidence of life history parameters of animals, such as cyclic and metabolic events throughout life, and are also more frequently preserved as fossils than other skeletal remains, they are an important tool for zoology and paleontology.
We propose a comparative analysis of modern and fossil cetacean dentitions, considering both macroscopic and microscopic approaches. Variations in tooth form and morphology will be evaluated in teeth samples of clades Delphinoidea and Platanistoidea, whose species are deposited both in New Zealand and overseas museums and scientific collections. Gross anatomy of teeth can reveal differences in size, shape and function of teeth between the two clades or among species which could have resulted in dietary or behavioral adaptations or even sexual dimorphism.

Microscopic analysis includes thin sectioning and evaluation of growth layers structure. The life-history of individual animals may be reflected in the incremental patterns of growth, represented by both the rate of change in tooth growth and by changes in chemical composition of each growth layer. As layers are presumed to remain metabolic inert after their formation, their isotopic composition encode a temporal record that may allow examinations of diet changes and trophic status. Ultra-structural approach may also reveal important aspects of life history of animals. Scanning electron microscopy of surface details and evaluation of microwear patterns and rates can help on the identification of striations and scratches related to dietary habits, the type and consistency of food or other morphological adaptations of teeth. Biomineral chemistry can also be an important source of information on cetacean dentitions. Stable isotopes analysis of carbon, nitrogen and oxygen provide evidence of food items consumed by cetaceans, as isotopic composition of hard tissues reflects nutritional sources.

Publications

• LOCH, C.; SWAIN, M.V.; JANSEN VAN VUUREN, L.; KIESER, J.A.; FORDYCE, R.E. 2013 Mechanical properties of dental tissues in dolphins (Cetacea: Delphinoidea and Inioidea). Archives of Oral Biology. doi:10.1016/j.archoralbio.2012.12.003
• LOCH, C. 2013. Return to the Sea: The Life and Evolutionary Times of Marine Mammals by Annalisa Berta. Marine Mammal Science 29(1): 236-237. doi:10.1111/j.1748-7692.2012.00619
• LOCH, C.; DUNCAN, W.; SIMÕES-LOPES, P.C.; KIESER, J.A.; FORDYCE, R.E. 2012. Ultrastructure of enamel and dentine in extant dolphins (Cetacea: Delphinoidea and Inioidea). Zoomorphology. doi:10.1007/s00435-012-0180-1
• LOCH, C.; SIMÕES-LOPES, P.C. 2012. Dental wear in dolphins (Cetacea: Delphinidae) from southern Brazil. Archives of Oral Biology.doi:10.1016/j.archoralbio.2012.08.002
• LOCH, C.; GRANDO, L.J.; SCHWASS, D.R.; KIESER, J.A.; FORDYCE, R.E.; SIMÕES-LOPES, P.C. 2012. Dental erosion in South Atlantic dolphins (Cetacea: Delphinidae): A macro and microscopic approach. Marine Mammal Science. doi:10.1111/j.1748-7692.2012.00562.x
• LOCH, C.; GRANDO, L.J.; KIESER, J.A.; SIMÕES-LOPES, P.C. 2011. Dental pathology in dolphins (Cetacea: Delphinidae) from the southern coast of Brazil. Diseases of Aquatic Organisms 94(3):225-234 doi:10.3354/dao02339
• LOCH,C.; SIMÕES-LOPES, P.C.; DREHMER, C.J. 2010. Numerical anomalies in the dentition of southern fur seals and sea lions. Zoologia, 27(3): 477-482. doi:10.1590/S1984-46702010005000001
• DREHMER, C.J.; J.E. DORNELLES; LOCH, C.2009. Variations on the dental formula of Otaria byronia de Blainville (Pinnipedia: Otariidae) in the Pacific Ocean: a new kind of dental anomaly. Neotropical Biology and Conservation, 4(1): 21-35 doi:10.4013/nbc.2009.41.04
• LOCH, C.; MARMONTEL, M.; SIMÕES-LOPES, P.C. 2009. Conflicts with fisheries and intentional killing of freshwater dolphins (Cetacea: Odontoceti) in the Western Brazilian Amazon. Biodiversity and Conservation, 18: 3979-3988. doi:10.1007/10531-009-9693-4

Conference Presentations

• LOCH, C.; KIESER, J.A.; FORDYCE, R.E. 2012. Phylogenetic vs. functional constraints in the evolution of odontocete enamel. In: 15th Meeting of Specialists in Aquatic Mammals from South America and 8th Congress of the Latin American Society of Specialists in Aquatic Mammals, Puerto Madryn, Argentina.
• DREHMER, C.J.; SANFELICE, D.; LOCH, C. 2012. Dental anomalies in pinnipeds (Carnivora: Otariidae and Phocidae) from the Southern Hemiphere. In: 15th Meeting of Specialists in Aquatic Mammals from South America and 8th Congress of the Latin American Society of Specialists in Aquatic Mammals, Puerto Madryn, Argentina.
• LOCH, C.; SCHWASS, D.; KIESER, J.A.; FORDYCE, E. 2011. Use of Micro-Computed Tomography for dental studies in modern and fossil odontocetes In: 19th Biennial Conference on the Biology of Marine Mammals, Tampa, USA.
• LOCH, C.; GRANDO, L. J., KIESER, J.E., FORDYCE, E., SIMOES-LOPES, P. C. 2010. Dental erosion in Delphinidae from southern Brazil: pathological aetiology or environmental influence? In: 14th Meetingof Specialists in Aquatic Mammals from South America and 7thCongress of the Latin American Society of Specialists in AquaticMammals, Florianópolis, Brazil.
• LOCH, C.; DUNCAN, W., KIESER, J.E., FORDYCE, E. 2010. Enamel ultrastructure in teeth of Globicephala (Delphinidae). In: 14th Meetingof Specialists in Aquatic Mammals from South America and 7thCongress of the Latin American Society of Specialists in AquaticMammals, Florianópolis, Brazil.
• COSTA, A.P.B, LOCH, C.; KOLESNIKOVAS,C., SIMOES-LOPES, P. C. 2010. Anthropic interactions as the cause of death of Pinnipeds in the Southern coast of Brazil. In: 14th Meetingof Specialists in Aquatic Mammals from South America and 7thCongress of the Latin American Society of Specialists in AquaticMammals, Florianópolis, Brazil.
• LOCH, C., LIMA, D.S., CALERA, B., MARMONTEL, M., MORATO, S.A.A. 2010. Monitoring of aquatic mammals populations in a mining area in the
  Sapucuá Lake (Oriximiná, PA, Brazil). In: 14th Meetingof Specialists in Aquatic Mammals from South America and 7thCongress of the Latin American Society of Specialists in AquaticMammals, Florianópolis, Brazil.
• LOCH, C.; GRANDO, L. J., KIESER, J.E., FORDYCE, E., SIMOES-LOPES, P. C. 2010. Dental erosion in South Atlantic Dolphins. In: 4th Biomouth Symposium, Christchurch, New Zealand.
• LOCH, C.; GRANDO, L. J., DREHMER, C. J., SIMOES-LOPES, P. C. 2008. Dental Pathologies in Delphinidae from Southern Brazil. In: 13rd Meetingof Specialists in Aquatic Mammals from South America and 6thCongress of Latin American Society of Specialists in AquaticMammals, Montevideo, Uruguay.
• LOCH, C.; GRANDO, L. J., FERNANDES, A., MEURER, M.I., ZASTROW, M.D., DREHMER, C. J., SIMOES-LOPES, P. C. 2008. Use of radiographs as a tool to evaluate dental anomalies in Delphinidae. In: 13rd Meeting of Specialists in Aquatic Mammals from SouthAmerica and 6th Congress of Latin American Society of Specialistsin Aquatic Mammals, Montevideo, Uruguay.
• LOCH, C.; SIMOES-LOPES, P. C., DREHMER, C. J. 2008. Dental anomalies in Pontoporia blainvillei (Cetacea: Pontoporiidae) from Santa Catarina coast. In: XXVII Brazilian Congress of Zoology - Curitiba, PR Brazil.
• LOCH, C.; SIMOES-LOPES, P. C., DREHMER, C. J. 2006. Pathologies and developmental alterations in teeth of small cetaceans from Southern Brazil. In: First International Meeting in Aquatic Mammals Research SOMEMMA-SOLAMAC - Mérida, México.
• LOCH, C.; MARMONTEL, M., SIMOES-LOPES, P. C. 2006. Cases of aggression and intentional killing of Inia geoffrensis and Sotalia fluviatilis in Western Brazilian Amazonia. In: First International Meeting about Aquatic Mammals Research SOMEMMA-SOLAMAC - Mérida, México.
• LOCH, C.; MARMONTEL, M., SIMOES-LOPES, P. C., DREHMER, C. J. 2006. Preliminary report of dental anomalies in Amazonian dolphins Inia geoffrensis and Sotalia fluviatilis from middle Solimões and Japurá region. In: 58th Reunion of Brazilian Society for Sciences Progress – Florianópolis SC, Brazil.
• LOCH, C.; MARMONTEL, M. 2006. Utilization of bone artifacts of the Amazonian manatee Trichechus inunguis by RDS Amanã (AM) local villagers. In:XXVI Brazilian Congress of Zoology - Londrina, PR Brazil.
• LOCH, C.; MARMONTEL, M. 2005. Environmental education and integration with local communities as a tool for recovering of biological samples of aquatic mammals on the RDS Amanã, AM, Northern Brazil. In:III Brazillian Congress of Mastozoology - Aracruz ES Brazil.
• LOCH, C.; DREHMER, C. J., SIMOES-LOPES, P. C. 2005. Dental anomalies in the sincranium of pinnipeds (Carnivora, Pinnipedia, Otariidae) from the coast of Santa Catarina and Rio Grande do Sul states, Southern Brazil. In:III Brazillian Congress of Mastozoology - Aracruz ES Brazil.
• LOCH, C.; DREHMER, C. J., SIMOES-LOPES, P. C. 2004. Dental wear in Tursiops truncatus and Sotalia guianensis (Cetecea: Odontoceti) In: 11th Meeting of Specialists in Aquatic Mammals from South America and 5th Congress of Latin America Society of Specialists in Aquatic Mammals - Quito, Ecuador.
• CASTILHO, P. V., LOCH, C.; SIMOES-LOPES, P. C. 2004. Twenty years of marine mammal strandings in Santa Catarina coast: review of patterns and seasonality. In:XXVBrazilian Congress of Zoology - Brasília, DF Brazil.