Bulletin of the Southern California Paleontological Society, vol. 3, no. 11, November 1971, p. 3-4

A DRAGONFLY NYMPH FROM THE MIOCENE OF SAN PEDRO, CALIFORNIA

by    Jack D. Mount¹

      In 1953 Bonnie C. Templeton of the Los Angeles County Museum of Natural History named and described a new species of fossil pine cone, Pinus paucisquamosa Templeton, based on a specimen that was collected along the beach between Cabrillo Beach and Point Fermin in San Pedro, California. During the summer of 1963 I visited the area of the type locality in an attempt to find additional pine cones. I was not successful, but I did collect a large silicified insect. Last month I showed it to Ken Frey who identified it as the nymph stage of a dragonfly. The specimen is now in the invertebrate paleontology collection of the Los Angeles County Museum of Natural History.

Location

      The slab of rock containing the insect was found as float material on the rocky beach below a high sea cliff about midway between Cabrillo Beach Museum and Lookout Point on Point Fermin.

Stratigraphy & Age

      The dragonfly is in cherty shale which, although found loose, is similar to rocks found in place in the cliffs. The geologic map in Woodring, Bramlette and Kew (1946) assignes the rocks of this area to the Altamira Shale Member of the Monterey Shale. On the basis of foraminifera, shale from this area is assigned to the Luisian Stage, Middle Miocene, by Kleinpell (in Woodring, Bramlette and Kew, 1946, p.24).

Order Odonata
Suborder Anisoptera
Family Libellulidae?

Fig. 1


Dragonfly Nymph
from San Pedro,
Calif. Miocene
Fig. 1
      The fossil dragonfly nymph is 23 mm long and 9 mm wide and is imperfectly preserved. It is questionably placed in the family shown above because of gross similarities to dragonfly nymphs found in the famous Calico nodules of Middle Miocene age from the Barstow Formation of San Bernardino County, California (Palmer, et al., 1957, p. 249-251). Dragonflies of this type are also found in the Miocene of Colorado and Oensingen, Switzerland.
      It is interesting to note that, although dragonfly nymphs live only in fresh water, this specimen and the pine cone were found in marine sediments. Other fossils reported from the Monterey Shale in the Cabrillo Beach-Point Fermin area include birds, fish, bones of whales and other sea mammals, leaves, and a few bivalves.

References Cited

Palmer, A. R., et al., 1957, Miocene arthropods from the Mojave Desert, California: U. S. Geol. Survey Prof. Paper 294-G, p. 237-280, 5 plates.

Templeton, B. C., 1953, A new record of pine cone for the Miocene Epoch: Bull. So. Calif. Acad. Sci., vol. 52, p. 64-66.

Woodring, W. P., Bramlette, M. N., and Kew, W. S. W., 1946, Geology and paleontology of Palos Verdes Hills, California: U. S. Geol. Survey Prof. Paper 207, 145 P.

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¹Southern California Paleontological Society. 1516 So. 5th St., Apt.H, Alhambra, CA 91803.


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