Ankalagon

Taxobox
name = "Ankalagon"
fossil_range = Early Paleocene


image_caption = "Ankalagon saurognathus"
image_width = 250px
regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = †Mesonychia
familia = †Mesonychidae
genus = †"Ankalagon"
genus_authority = Van Valen, 1980
species = †"A. saurognathus"
binomial = †"Ankalagon saurognathus"
binomial_authority = (Wortman, in Matthew, 1897)
synonyms = "Dissacus saurognathus"

"Ankalagon saurognathus" is an extinct mesonychid mammal known from the Paleocene of New Mexico. "Ankalagon" is the largest mesonychid known from the Paleocene of North America, and it provides the best evidence for sexual dimorphism in mesonychids.cite journal | author = O'Leary, M.A., S.G. Lucas, and T.E. Williamson | year = 2000 | title = A new specimen of "Ankalagon" (Mammalia, Mesonychia) and evidence of sexual dimorphism in mesonychians | journal = Journal of Vertebrate Paleontology | volume = 20 | issue = 2 | pages = 387–393 | doi = 10.1671/0272-4634(2000)020 [0387:ANSOAM] 2.0.CO;2 | doilabel = 10.1671/0272-4634(2000)020[0387:ANSOAM]2.0.CO;2]

Description

The main feature that distinguishes "A. saurognathus" from the ancestral "Dissacus" species is its size: "Ankalagon" grew to be as large as a bear [Paleocene mammals of the world "Carnivores, creodonts and carnivorous ungulates: Mammals become predators" [http://www.paleocene-mammals.de/predators.htm] ] , as compared to the coyote or jackal-sized species of "Dissacus". In fact, the only North American mesonychids that surpassed "Ankalagon" in size were the larger species of the Early Eocene genus, "Pachyaena", such as "P. gigantea" and "P. ossifraga", which, too, grew to the size of bears [Paleocene mammals of the world "Carnivores, creodonts and carnivorous ungulates: Mammals become predators" [http://www.paleocene-mammals.de/predators.htm] ] .

Evidence of sexual dimorphism comes from the fact that some jawbones were larger, and had more massive molar teeth better suited to crushing bones than other jawbones, suggesting that the males crushed bones.cite journal | author = O'Leary, M.A., S.G. Lucas, and T.E. Williamson | year = 2000 | title = A new specimen of "Ankalagon" (Mammalia, Mesonychia) and evidence of sexual dimorphism in mesonychians | journal = Journal of Vertebrate Paleontology | volume = 20 | issue = 2 | pages = 387–393 | doi = 10.1671/0272-4634(2000)020 [0387:ANSOAM] 2.0.CO;2 | doilabel = 10.1671/0272-4634(2000)020[0387:ANSOAM]2.0.CO;2]

Ecology

The strong jaws, sharp, hooked canines and triangular molars that form a shearing edge typical of other mesonychids suggest that "A. saurognathus" was a hypercarnivorous apex predator. The massive molars of the males suggest that the males were also scavengers that ate bones.

Etymology

The generic name refers to the dragon Ancalagon, who was mentioned in the Silmarillion by J.R.R. Tolkien. In the Silmarillion, Ancalagon was described as being one of the more powerful servants of the malevolent being, Morgoth, having been bred to be the fiercest, mightiest, and largest dragon in all of Middle Earth. According to Tolkien, "Ancalagon" translates from Sindarin as being "anc" 'jaw', "alag" 'impetuous' [ME-ref|LROW|"The Etymologies", pp. 348, 362] .

Leigh Van Valen studied the New Mexico mesonychid "Dissacus saurognathus" and eventually came to the conclusion that "D. saurognathus" differed enough from the sympatric "D. navajovius", and from other members of the genus to merit its own genus. Van Valen intended to erect the genus "Ancalagon"," but found that it was already occupied by a Middle Cambrian priapulid described by Simon Conway Morris, "Ancalagon minor", a possible ancestor of the parasitic acanthocephalids [Williams, H. H., Jones, A. 1994. Parasitic Worms of Fish CRC Press. p 284] .

The species name, "saurognathus," translates as "lizard jaw."

References