When Dolphin Skulls Talk

Dolphin taxonomy - what the skulls tell us

Museums that house natural history collections such as marine mammals play a significant role in zoological research and dissemination of scientific results to society and in detecting  different patterns between  historical and current biodiversity. This is particularly valuable for cetacean collections in which skeletal or other remains of specimens are preserved  from specimens that have stranded or died as a result of accidental captures in fishing nets (bycatch). It is through these collections that we get to study different biological aspects of these animals such as their much discussed taxonomy, particularly in the smaller delphinids.

The skull is frequently the most available skeletal part for morphological studies in natural history collections. As a result, skull morphology has been one of the popular techniques used to study differences between and within populations. The skulls of animals are considered the most suitable skeletal material for morphological studies as they frequently show variation in size and shape depending on ontogeny, sex, and geographic location.

Bayworld has a longstanding stranding programme in which skulls and other samples are collected from dead cetacean strandings and thus houses one of the largest marine mammal collection in the world. By using skulls of common and bottlenose dolphins from Bayworld and Iziko South African Museums, differences between populations of common dolphins were revealed. Additionally, two morphologically distinct species of bottlenose dolphins were revealed. These cetaceans have been in contentious discussions regarding their taxonomy and it seems we still have lot to learn from them by incorporating modern techniques such as genetics.

ABOUT DR SIBU NGQULANA

Dr Sibu Ngqulana is the collections manager at Bayworld. She has a PhD in zoology and graduated from Nelson Mandela University. Before her current work, Sibu was a contract lecturer at the NMU zoology and botany departments.  She interned and volunteered at Bayworld while completing her PhD with Greg Hofmeyr as her supervisor. 

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