The family Camelidae had its origins in North America during the middle
Eocene, about 44 million years ago. Camels went extinct about 11,000 years
ago in North America, but are survived by the modern llamas in South America,
and camels in Africa and Asia. In the Anza-Borrego paleontological record,
camels are the second-most common group, second only to the Family Equidae,
horses. But their diversity is greater than that exhibited by the Equidae, with at
least eight different forms of camels known. These various members of the family
range from the oldest to the youngest Anza-Borrego deposits, from greater
than 5 to less than 0.5 million years.
The modern Anza-Borrego Desert is a treasure trove of camelid fossils
and is quite possibly the greatest for any site in North America. Although other
Pliocene and Pleistocene localities in California, such as Bautista Creek, Clark
Park, Irvington, Lake Manix, Rancho La Brea, San Timoteo, and Tehama yield
fossil camelid remains, none has the diversity of Anza-Borrego. Here, the paleofaunal
assemblages open a window into Plio-Pleistocene evolution of camelids
in North America. Camelid finds include both Tribes (subdivisions of Families)
of modern camelids: the Tribe Lamini, represented today by llamas of South
America, and the Tribe Camelini, today’s camels of the Old World. Together
these encompass five genera, including four Lamini and one Camelini.
Taxonomically, this constitutes the richest assemblage of Plio-Pleistocene
camelids known anywhere, and these finds have helped shape our knowledge of
camelid emergence and evolution in North America.
What tribes of Lamini are found in Anza-Borrego?
Three North American species are known: Hemiauchenia blancoensis,
H. macrocephala (Figure 17.5), and H. vera. H. vera, is temporally restricted to
the Hemphillian NALMA (earliest age in Anza-Borrego). It is represented by
only a few Anza-Borrego specimens recovered from the 5 million-year-old shallow
marine sandstones of the Latrania Formation, including a complete lower
jaw (Fossil Treasures Figure 17.4).
The presence of Hemiauchenia in the Anza-Borrego assemblages from
the Hueso Formation is based on long metapodials (Fossil Treasures Figure 17.3) and dental features.
Unfortunately, the diagnostic element that would most distinguish H.
blancoensis from H. macrocephala, the lower fourth premolar tooth, has not yet
been found in Anza-Borrego. Both H. blancoensis and H. macrocephala, owing
to their known geographic and temporal ranges, most likely occur in Anza-
Borrego. However, to further substantiate this, the discovery of more diagnostic
material is needed.
A fourth, yet undescribed, form of Hemiauchenia was recently recognized
in the Anza-Borrego Desert collection. This new animal is represented
by a very slender metapodial (Fossil Treasures Figure 17.3) and small phalanges, smaller than
either H. macrocephala or H. blancoensis. Features in the lower dentition,
although only slightly smaller than H. macrocephala, also distinguish it from
H. blancoensis, H. macrocephala, and H. vera.
What types of Camelini are found in Anza-Borrego?
The Camelini originated in the late Miocene of North America. Most
students of fossil Camelidae consider Procamelus to be the Miocene genus with
closest affinities to modern camels. Taxa assigned to this Tribe are generally
very large and tend to have longer rostra, Greek for snout or nose, and flatter
skulls than the Lamini. The four currently recognized genera, Megacamelus,
Megatylopus, Titanotylopus, and Gigantocamelus, are well known from the
Great Plains states, but also occur in the western U.S. Only the Gigantocamelus
occurs in Anza-Borrego.
How could so many types of camels live together in Anza-Borrego?
The Anza-Borrego Camelidae include at least eight species (Fossil Treasures Appendix,
Table 3), the richest assemblage of nearly modern camelids known anywhere.
The presence of a wide array of camels and llamas also is confirmed by their
extensive trackways in muddy deposits of the Anza-Borrego geological section
(Remeika, 2001, and this volume, Fossil Footprints of Anza-Borrego). This rich
and diverse record raises the question of how so many different types of camels
and llamas could have lived together within one area. A partial answer is, of
course, that these animals did not all live at exactly the same time. Not more
than four or five species lived within the same NALMA (Fossil Treasures Cassiliano, this
volume, Mammalian Biostratigraphy in the Vallecito Creek-Fish Creek Basin).
👉 Read Fossil Treasures (searchable PDF)
Eocene, about 44 million years ago. Camels went extinct about 11,000 years
ago in North America, but are survived by the modern llamas in South America,
and camels in Africa and Asia. In the Anza-Borrego paleontological record,
camels are the second-most common group, second only to the Family Equidae,
horses. But their diversity is greater than that exhibited by the Equidae, with at
least eight different forms of camels known. These various members of the family
range from the oldest to the youngest Anza-Borrego deposits, from greater
than 5 to less than 0.5 million years.
The modern Anza-Borrego Desert is a treasure trove of camelid fossils
and is quite possibly the greatest for any site in North America. Although other
Pliocene and Pleistocene localities in California, such as Bautista Creek, Clark
Park, Irvington, Lake Manix, Rancho La Brea, San Timoteo, and Tehama yield
fossil camelid remains, none has the diversity of Anza-Borrego. Here, the paleofaunal
assemblages open a window into Plio-Pleistocene evolution of camelids
in North America. Camelid finds include both Tribes (subdivisions of Families)
of modern camelids: the Tribe Lamini, represented today by llamas of South
America, and the Tribe Camelini, today’s camels of the Old World. Together
these encompass five genera, including four Lamini and one Camelini.
Taxonomically, this constitutes the richest assemblage of Plio-Pleistocene
camelids known anywhere, and these finds have helped shape our knowledge of
camelid emergence and evolution in North America.
What tribes of Lamini are found in Anza-Borrego?
Three North American species are known: Hemiauchenia blancoensis,
H. macrocephala (Figure 17.5), and H. vera. H. vera, is temporally restricted to
the Hemphillian NALMA (earliest age in Anza-Borrego). It is represented by
only a few Anza-Borrego specimens recovered from the 5 million-year-old shallow
marine sandstones of the Latrania Formation, including a complete lower
jaw (Fossil Treasures Figure 17.4).
The presence of Hemiauchenia in the Anza-Borrego assemblages from
the Hueso Formation is based on long metapodials (Fossil Treasures Figure 17.3) and dental features.
Unfortunately, the diagnostic element that would most distinguish H.
blancoensis from H. macrocephala, the lower fourth premolar tooth, has not yet
been found in Anza-Borrego. Both H. blancoensis and H. macrocephala, owing
to their known geographic and temporal ranges, most likely occur in Anza-
Borrego. However, to further substantiate this, the discovery of more diagnostic
material is needed.
A fourth, yet undescribed, form of Hemiauchenia was recently recognized
in the Anza-Borrego Desert collection. This new animal is represented
by a very slender metapodial (Fossil Treasures Figure 17.3) and small phalanges, smaller than
either H. macrocephala or H. blancoensis. Features in the lower dentition,
although only slightly smaller than H. macrocephala, also distinguish it from
H. blancoensis, H. macrocephala, and H. vera.
What types of Camelini are found in Anza-Borrego?
The Camelini originated in the late Miocene of North America. Most
students of fossil Camelidae consider Procamelus to be the Miocene genus with
closest affinities to modern camels. Taxa assigned to this Tribe are generally
very large and tend to have longer rostra, Greek for snout or nose, and flatter
skulls than the Lamini. The four currently recognized genera, Megacamelus,
Megatylopus, Titanotylopus, and Gigantocamelus, are well known from the
Great Plains states, but also occur in the western U.S. Only the Gigantocamelus
occurs in Anza-Borrego.
How could so many types of camels live together in Anza-Borrego?
The Anza-Borrego Camelidae include at least eight species (Fossil Treasures Appendix,
Table 3), the richest assemblage of nearly modern camelids known anywhere.
The presence of a wide array of camels and llamas also is confirmed by their
extensive trackways in muddy deposits of the Anza-Borrego geological section
(Remeika, 2001, and this volume, Fossil Footprints of Anza-Borrego). This rich
and diverse record raises the question of how so many different types of camels
and llamas could have lived together within one area. A partial answer is, of
course, that these animals did not all live at exactly the same time. Not more
than four or five species lived within the same NALMA (Fossil Treasures Cassiliano, this
volume, Mammalian Biostratigraphy in the Vallecito Creek-Fish Creek Basin).
👉 Read Fossil Treasures (searchable PDF)
