Líffræðifélag Íslands
Líffræðiráðstefnan 2013
Erindi 14

Bones in motion: morphometrics of craniofacial development of Arctic charr sympatric morphs

Kalina H. Kapralova (1), Arnar Pálsson (1), Bjarni K. Kristjánsson (2), Soizic Le Deuff (2), Jannika Neeb (1), Sigríður Rut Franzdóttir (1), Zophonías O. Jónsson (1) og Sigurður S. Snorrason (1)

1) Háskóli Íslands
2) Háskólinn á Hólum

Kynnir: Kalina H. Kapralova
Tengiliður: Sigurður S. Snorrason (sigsnor@hi.is)

A central question in many many ecological and evolutionary studies is how different morphological phenotypes arise through variation in development. Icelandic Arctic charr  shows an extremely high level of phenotypic variation  among populations and many examples of polymorphism (i.e. sympatric morphs) have  been documented. The four morphs of Arctic charr, planctivorous (PL), piscivorous (PI) , small (SB) and large benthivorous (LB)  of Lake Thingvallavatn constitute an extreme example of local phenotypic diversity. These morphs differ largely in their craniofacial morphology (benthic morphs have a blunt snout and short lower jaw, whereas PL and PI have pointed snout and evenly protruding jaws. We studied the craniofacial development of three Arctic charr morphs from Thingvallavatn (SB, PL and LB) and in an outgroup, aquaculture charr (AC) from the Hólar breeding stock. We created pure crosses from each group and sampled  offspring groups at six time points during development, from hatching until start of feeding. We used geometric morphometrics  to address questions like: 1) What are the principal axes of variation in Arctic charr craniofacial development? 2) Are shape and size correlated? 3) Which axes of variation change during development? 4) What is the degree of modularity in the developing charr head? In addition we investigatied how development differs among morphs. Futhermore we evaluate the effect of hybridisation on head development by looking at reciprocal hybrids (SB and PL). The preliminary results show that the first 6 morphological axes account for 78% of the variation with the first 3 axes alone accounting for 65%. As expected developmental time contribute the most to the variation on the principal axes. However a significant proportion of the variation is explained by morph. Shape and size are corelated for all the samples under study.