Boreostemma

Boreostemma is an extinct genus of glyptodonts from northern South America. Fossils assigned to the genus were first described as belonging to Asterostemma from southern South America, but have been placed in the new genus Boreostemma by Carlini et al. in 2008. The type species is B. pliocena. Fossils of Boreostemma have been found in the Honda Group of Colombia, in Peru and Venezuela.

Boreostemma
Tail of Boreostemma from the Honda Group
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cingulata
Family: Chlamyphoridae
Subfamily: †Glyptodontinae
Genus: †Boreostemma
Carlini et al. 2008
Type species
Boreostemma pliocena
Carlini et al. 2008
Species
  • B. acostae Villarroel 1983
  • B. gigantea Carlini et al. 1997
  • B. pliocena Carlini et al. 2008
  • B. venezolensis Simpson 1947

Etymology

The genus name Boreostemma is a combination of stemma, taken from Asterostemma, and boreo is derived from borealis, meaning "northern", to distinguish the northern South American genus from the southern Asterostemma.[1]

Species
Locations of Boreostemma and Asterostemma fossil finds in South America
Asterostemma
B. acostae & B. gigantea
B. pliocena (type)
B. venezolensis
Boreostemma sp.

Four species have been described in the genus Boreostemma.[2] Unspecified Boreostemma fossils were found in the Ipururo Formation of the department of Ucayali, Amazonian Peru.[3][4][5] Asterostemma contains the type species A. depressa and several nomina dubia. The genus has been found in the Early Miocene (Santacrucian in the SALMA classification) Santa Cruz Formation of the province of Santa Cruz, Argentina and in the Solimões Formation in the state of Acre, Amazonian Brazil.[6][7]

B. pliocena

The type species B. pliocena was described in 2008 by Carlini et al. based on 30 osteoderms palate fragment with M6-7 alveoli.[8] Fossils have been described from the type locality along the road to Tío Gregorio in the Codore Formation at the Lagerstätte of Urumaco.[9]

B. gigantea

B. gigantea was described as Asterostemma gigantea in 1997 by Carlini et al. based on a partial skeleton.[10] Fossils have been recovered at the Duke Localities 32, 108, 113, 114 and 121W in the La Victoria Formation of the Honda Group at the Konzentrat-Lagerstätte La Venta.[11][12][13][14][15]

B. acostae

B. acostae was described as Asterostemma acostae in 1983 by Carlos Villarroel based on a carapace fragment with 44 plates.[16] Fossils have been found in the Cerbatana Member, and the Chunchullo Sandstone of the La Victoria Formation, of the Honda Group at the Konzentrat-Lagerstätte La Venta.[17][18]

B. venezolensis

B. venezolensis was described as Asterostemma venezolensis in 1947 by George Gaylord Simpson,[19] based on most of the carapace and the anterior end of the lower jaw, including teeth.[20] Fossils have been uncovered from the Santa Inés Formation along the banks of the Güere River in the state of Anzoátegui in Venezuela.[21]

  • Carapace of Boreostemma
  • Reconstruction

See also

References
  1. Carlini et al. 2008, p. 142.
  2. Boreostemma at Fossilworks.org
  3. IN-DTC-28 at Fossilworks.org
  4. IN-DTC-32 at Fossilworks.org
  5. IN007 at Fossilworks.org
  6. Cañadón Jack, Yak-Harvey at Fossilworks.org
  7. Rio Acre at Fossilworks.org
  8. Boreostemma pliocena at Fossilworks.org
  9. Road to Tio Gregorio Locality at Fossilworks.org
  10. Boreostemma gigantea at Fossilworks.org
  11. Duke Locality 32 at Fossilworks.org
  12. Duke Locality 108 at Fossilworks.org
  13. Duke Locality 113 at Fossilworks.org
  14. Duke Locality 114 at Fossilworks.org
  15. Duke Locality 121W at Fossilworks.org
  16. Boreostemma acostae at Fossilworks.org
  17. Arcillas San Nicolas at Fossilworks.org
  18. Chunchullo Sandstone at Fossilworks.org
  19. Simpson, 1947, p.2
  20. Boreostemma venezolensis at Fossilworks.org
  21. Banks of the Güere River at Fossilworks.org

Bibliography
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