Dagonodum mojnum

Dagonodum mojnum was an extinct odontocete cetacean belonging to Ziphiidae, the group of beaked whales, known from fossils from the Late Miocene of Denmark. Its remains come from the Gram Formation, a Tortonian marine unit that records ancient coastal and shallow-water environments in northern Europe. Formally described by Benjamin Ramassamy in 2016, Dagonodum mojnum represents the first evidence of a fossil ziphiid in Denmark and provides relevant information on the early evolution of beaked whales, particularly regarding suction feeding, dental reduction, and the sexual dimorphism characteristic of many modern members of the group.

Unlike the more specialized living beaked whales, which usually have highly reduced dentitions and rely mainly on suction feeding in deep-water environments, Dagonodum mojnum retains a more basal combination of features. Its skull shows a very elongated rostrum, representing approximately 70% of the total condylobasal length, as well as a narrow and elongated mandible adapted to a more active type of prey capture. One of its most distinctive features is the presence of a relatively numerous dentition for a ziphiid, with multiple functional teeth and pairs of forward-projecting mandibular tusks. This dental pattern, together with the wear observed on the teeth, suggests that Dagonodum did not rely exclusively on suction feeding, but probably captured and held prey more directly.

The cranial anatomy of Dagonodum mojnum includes a marked premaxillary crest at the vertex of the skull, a characteristic feature of ziphiids, as well as ear and nasal-region features indicating a less specialized condition than that seen in many modern beaked whales. The combination of a long snout, abundant dentition, developed tusks, and a relatively mobile neck suggests an animal adapted to capturing small fish, cephalopods, or other firm-bodied prey in coastal marine environments. The presence of enlarged, worn tusks has also been interpreted as possible evidence of intraspecific interactions, perhaps related to competition, display, or combat, although this interpretation should be understood within the comparative framework of other fossil and living ziphiids.

Dagonodum mojnum inhabited a rich and diverse marine ecosystem during the Late Miocene, in a region where molluscs, crustaceans, sharks, other cetaceans, and marine vertebrates associated with the Gram Formation have been documented. This palaeoenvironmental context suggests relatively shallow and productive seas, very different from the deep-ocean habitats occupied by many modern beaked whales. Its phylogenetic position as a basal ziphiid, close to longirostrine forms such as Messapicetus, makes it a key species for understanding the evolutionary transition between odontocetes with functional dentitions and modern beaked whales, which are highly specialized for suction feeding.

This replica represents Dagonodum mojnum as a primitive beaked whale with an extremely elongated snout, a streamlined body, a narrow mandible, and visible functional dentition, integrating the known features of its cranial anatomy and ecological interpretation. Its reconstruction highlights the uniqueness of this Late Miocene Danish cetacean: a ziphiid still capable of capturing prey through direct dental contact, while already displaying several of the specializations that characterize beaked whales within odontocete evolution.

Approximate measurements of Dagonodum:

Scale 1:35 — Complete model
Length: 130 mm
Height: 43 mm
Width: 32 mm
Snout-to-tail length: 142 mm

Scale 1:20 — Complete model
Length: 227 mm
Height: 75 mm
Width: 55 mm
Snout-to-tail length: 250 mm