comment on this calibration
Whippomorpha - Ruminantia
Lineage (NCBI):
root
» Eukaryota
» Opisthokonta
» Metazoa
» Eumetazoa
» Bilateria
» Coelomata
» Deuterostomia
» Chordata
» Craniata <chordata>
» Vertebrata <Metazoa>
» Gnathostomata <vertebrate>
» Euteleostomi
» Sarcopterygii
» Tetrapoda
» Amniota
» Mammalia
» Theria <Mammalia>
» Eutheria
» Laurasiatheria
» Cetartiodactyla
| node name Whippomorpha - Ruminantia Look for this name in NCBI Wikipedia Animal Diversity Web | ||
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recommended citations http://palaeo-electronica.org/content/fc-1 Benton et al. 2015 |
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node minimum age 52.4 Ma The cow-pig division is dated minimally by the record of Himalayacetus from the base of the Subathu Formation in Pakistan (Bajpai and Gingerich, 1998) where it co-occurs with Nummulites atacicus whose range correlates with nannoplankton zones 11-12, providing a minimum age of 52.4 Ma (Martín-Martín et al., 2001). The availability of this marine correlation for this fossil enables us to forego use of the corresponding marine stage (Ypresian). | ||
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node maximum age 66 Ma The absence of any crown cetartiodactyls during the Paleocene may point to a soft maximum constraint of 66.04 Ma ± 0.4 Myr = 66 Ma | ||
| primary fossil used to date this node | ||
RUSB 2003 | ||
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phylogenetic justification
Himalayacetus is known only from a partial dentary and two molars, but it was claimed that these show characterisics of Pakicetidae (Bajpaj and Gingerich, 1998), The phylogenetic placement within Cetacea is controversial, and a conservative phylogenetic analysis (O’Leary and Uhen, 1999) confirmed that Himalayacetus might be more closely related to ambulocetids than to pakicetids. Either way, Himalayacetus is a member of total-group Cetacea, and nested well within crown Whippomorpha. |
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phylogenetic reference(s)
O’Leary, M.A. and Uhen, M.D. 1999. The time of origin of whales and the role of behavioral changes in the terrestrial-aquatic transition. Paleobiology, 25:534–556.
Bajpai, S. and Gingerich, P.D. 1998. A new Eocene archaeocete (Mammalia, Cetacea) from India and the time of origin of whales. Proceedings of the National Academy of Sciences, USA, 95:15464-15468.
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