title: Bones in motion: Ontogeny of craniofacial development in sympatric arctic charr morphs.
abstract: BACKGROUND
  The impressive diversity in the feeding apparatus often seen among related fish species clearly reflects differences in feeding modes and habitat utilization. Such variation can also be found within species. One example of such intraspecific diversity is the Arctic charr in Lake Thingvallavatn, where four distinct morphs coexist: two limnetic, with evenly protruding jaws, and two benthic, with subterminal lower jaws. We used these recently evolved morphs to study the role of ontogenetic variation in shaping craniofacial diversity.
  
  
  RESULTS
  The segmental development of the pharyngeal arches and the order of events in craniofacial development is the same as has been described for teleosts, emphasizing the conserved nature of this process. However, our morphometric analyses reveal differences between morphs. Hatching is accompanied by increase in size and allometric shape changes in Arctic charr. Ontogenetic trajectories of craniofacial shape also differ significantly between morphs.
  
  
  CONCLUSIONS
  The results point to hatching as a significant developmental event in Arctic charr and possibly other fishes. Also, the developmental origins of limnetic and benthic specializations in the craniofacial elements of Arctic charr may stem from events around hatching. This calls for investigations of the mechanisms and consequences of hatching, in the context of development and evolution. Developmental Dynamics 244:1168-1178, 2015. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Institute of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: Kalina H
authors.initials: KH
authors.lastname: Kapralova
authors.affiliation: Institute of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: Zophonías O
authors.initials: ZO
authors.lastname: Jónsson
authors.affiliation: Institute of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: Arnar
authors.initials: A
authors.lastname: Palsson
authors.affiliation: Institute of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: Sigrídur Rut
authors.initials: SR
authors.lastname: Franzdóttir
authors.affiliation: Holar University College, Saudarkrokur, Iceland.
authors.forename: Soizic
authors.initials: S
authors.lastname: le Deuff
authors.affiliation: Holar University College, Saudarkrokur, Iceland.
authors.forename: Bjarni Kristófer
authors.initials: BK
authors.lastname: Kristjánsson
authors.affiliation: Institute of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: Sigurður S
authors.initials: SS
authors.lastname: Snorrason
keywords: Arctic charr; geometric morphometrics; hatching; ontogenetic trajectories; trophic polymorphism