Diacodexis
Name:
Diacodexis.
Phonetic: De-ah-cpe-dex-iss.
Named By: Edward Drinker Cope - 1882.
Synonyms: Gujaratia, Trigonolestes.
Classification: Chordata, Mammalia,
Artiodactyla, Dichobunidae.
Species: D. antunesi, D. gazini,
D. gracilis, D. ilicis, D. indicus, D. kelleyi, D.
metsiacus, D. minutus, D. pakistanensis, D. parvus, D.
primus, D. secans, D. woltonensis.
Diet: Herbivore.
Size: Up to 50 centimetres long.
Known locations: Across Eurasia and North America.
Time period: Ypresian to Lutetian (possibly
Bartonian) of the Eocene.
Fossil representation: Hundreds of specimens.
Diacodexis
is an early indicator of the forms that the ungulates (hoofed
mammals) evolved from, though Diacodexis may
not have been ‘the’
ancestor even though it was certainly related to them. The main clue
that Diacodexis is a candidate for being an
ancestral form of
artiodactyl is that while the feet still have five toes, the third
and fourth toes were slightly elongated. Through successive
generations over the course of millions of years, these two toes
would form the foundation of hooves while the other three toes would
reduce to the point of being vestigial.
In
life Diacodexis would have lived in a similar
manner to a small deer,
remaining hidden in dense undergrowth while browsing and only walking
out in the open when absolutely necessary. While its body shape and
proportions are indeed similar however, Diacodexis
had a much longer
tail. The long legs of Diacodexis are
proportioned like those of a
runner and it’s possible that if it could not stay hidden from
predators, it may have tried running through the undergrowth to
escape them. In such a scenario the long legs would also allow
Diacodexis to more easily clear ground obstacles
like exposed roots and
fallen branches than shorter legged pursuers.
Further reading
- Two new genera of Mammalia from the Wasatch Eocene. - American
Naturalist 16(12):1029. - E. D. Cope - 1882.
- Diagnoses de trois nouvelles especes de mammiferes du Sparnacien de
Provence. - Compte rendu sommaire des seances de la Societe geologique
de France 1978(6):286-288. - M. Godinot - 1978.
- Revision of the Eocene Wind River Faunas, Early Eocene of Central
Wyoming. Part 7. Revision of Diacodexis (Mammalian,
Artiodactyla). -
Annals of Carnegie Museum 54(14):413-486. - L. Krishtalka & R.
K. Stucky - 1985.
- Decouverte d'un nouveau Diacodexis (Artiocactyla, Mammalia) dans
l'Eoc�ne inf�rieur de Silveirinha, Portugal. Palaeovertebrata
19(1):29-44. - C. Estrav�s & D. E. Russell - 1989.
- New earliest Wasatchian mammalian fauna from the Eocene of
northwestern Wyoming: composition and diversity in a rarely sampled
high-floodplain assemblage. - University of Michigan Papers on
Paleontology 28:1-97. - P. D. Gingerich - 1989.
- Early Eocene land mammals from Vastan Lignite Mine, District Surat
(Gujarat), Western India. - Journal of the Palaeontological Society of
India 50(1):101-113. - S. Bajpai, V. V. Kapur, D. P. Das, B. N. Tiwari,
N. Saravanan & R. Sharma - 2005.
- The mammal fauna of the early Eocene Blackheath Formation of Abbey
Wood, London. - Monograph of the Palaeontographical Society 165:1-162.
- J. J. Hooker - 2010.
- Early Eocene artiodactyls (Mammalia) from western India. Journal of
Vertebrate Paleontology 30(4):1245-1274. - K. Kumar, K. D. Rose, R. S.
Rana, L. Singh, T. Smith & A. Sahni - 2010.
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