Samlinger Lokaliteter TidstavleFaunalister Blin

Mesoplodon? sp.

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 Faktiske data om fund 
DK 895
Statens Naturhistorisk Museum
Zina Fihl
Bestemt af:
Benjamin Ramassamy
Gram Lergrav
Gram Formationen
Øvre Miocæn
Gram Ler


Foto ©:

 Beskrivelse:   af  Benjamin Ramassamy 
A 10 million year old fossil beaked whale from the Gram Formation represents a new species with unique adaptations related to feeding behavior. It consists in a subcomplete lower jaw, a tongue bone, several isolated teeth including a tusk, two periotic bones (one with the stapes) and the tympanic bulla, a humerus, and fragments of the cranium including the eroded nasals and part of the premaxillary sac fossa.
Based on the proportions of the jaw, the specimen is considered to be one of the largest fossil of beaked whales ever found, close in terms of size to the extant species Mesoplodon layardii.

The other species of beaked whale represented in the Gram claypit is Dagonodum mojnum, a basal species among the beaked whales. This smaller type of beaked whale is characterized by elongated jaws bearing numerous teeth. On the contrary, the new specimen of beaked whale is characterized by shorter jaws, a reduction of the teeth count and a thickened tongue bones where insert strong tongue muscles used to create powerful suction pressures.

The coexistence of the two types of beaked whales in the Gram claypit is an example of niche separation. Such cases are already known in extant beaked whales, where species of different sizes feed upon different prey types to avoid interspecific competition. While Dagonodum mojnum was feeding on small fish, this new beaked whale would favor larger prey, and perhaps feed on cephalopods , the favored prey type of extant beaked whales.

I recommend this fossil to the Danekræ comity for its high scientific value and its exhibition value due to the rarity of fossil beaked whales found in the Gram claypit.

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