LACM 149371
LACM 149371 (
LACM 149371 was described in 2004 by Francisco Goin and colleagues, who tentatively interpreted the tooth as a left last upper
Discovery and context
LACM 149371 was discovered in 1998 at the
The age of the Santa Rosa fauna remains highly uncertain, as the
Description
LACM 149371 is a poorly preserved
The crown of the tooth is triangular and contains six
For convenience, Goin and colleagues designated the six cusps as A through F: A on the front labial corner of the tooth; B on the labial face; C on the back corner; D on the lingual (inner) face; E on the front lingual corner; and F on the front face. The large front fossa is located between cusps A, B, D, E, and F; the smaller intermediate fossa is between cusps B and D; and the much smaller back fossa is just in front of cusp C.[9] All three are nearly round.[8] Cusp A, the largest cusp, is triangular in shape and is separated from the smaller, rounded B by a deep valley; a low crest connects the two cusps further lingually, separating the valley from the front fossa.[10] At its back, B connects to a long crest that reaches the back fossa and behind it the small cusp C, which has a groove on its labial side. A valley separates it from cusp D.[11] D itself is crest-shaped and forms the lingual wall of the intermediate fossa;[12] it is described as "very odd", and may in fact consist of two fused, triangular cusps.[13] A crest issuing from D separates the back from the intermediate fossa, and another, larger crest separates the front from the back fossa and nearly reaches cusp B. Cusp E is triangular and separated from cusps F and D by valleys, which are bordered internally by crests connecting the cusps. F is rounded. The microstructure of the tooth enamel is not clearly recognizable, evidently because the tooth is degraded, though structures resembling enamel prisms (bundles of hydroxyapatite crystals) and Hunter-Schreger bands are recognizable.[8]
Identity
Because of the complexity of the crown, Goin and colleagues identified the tooth as a mammal; although some non-mammalian groups, like
The tooth resembles
References
- ^ a b c Goin et al., 2004, p. 145
- ^ Campbell, 2004, pp. 156–159
- ^ Goin et al., 2004
- ^ Campbell, 2004, pp. 159–160
- ^ Vucetich et al., 2010, pp. 201–202
- ^ Campbell, 2004, p. 161
- ^ a b Goin et al., 2004, p. 146
- ^ a b c d e f Goin et al., 2004, p. 149
- ^ Goin et al., 2004, p. 146, fig. 2
- ^ Goin et al., 2004, p. 147
- ^ Goin et al., 2004, pp. 147–148
- ^ Goin et al., 2004, pp. 148–149
- ^ Goin et al., 2004, p. 148
- ^ a b Goin et al., 2004, p. 151
- ^ Goin et al., 2004, pp. 151–152
- ^ a b Goin et al., 2004, p. 152
Bibliography
- Campbell, K.E., Jr. 2004. The Santa Rosa local fauna: A summary. Science Series, Natural History Museum of Los Angeles County 40:155–163.
- Goin, F.J., Vieytes, E.C., Vucetich, M.G., Carlini, A.A. and Bond, M. 2004. Enigmatic mammal from the Paleogene of Perú. Science Series, Natural History Museum of Los Angeles County 40:145–153.
- Vucetich, M.G., Vieytes, E.C., Pérez, M.E. and Carloni, A.A. 2010. The rodents from La Cantera and the early evolution of caviomorphs in South America. pp. 193–205 in Madden, R.H., Carlini, A.A., Vucetich, M.G. and Kay, R.F. (eds.). The Paleontology of Gran Barranca: Evolution and Environmental Change Through the Middle Cenozoic of Patagonia. Cambridge University Press, 458 pp. ISBN 978-0-521-87241-6