Bulbaspis

Bulbaspis ("bulb shield") is a late Ordovician genus of asaphid trilobites of the family Raphiophoridae found primarily in upper Ordovician-aged deepwater marine strata of Kazakhstan, China, and possibly Tasmania. Species of Bulbaspis are similar to other raphiophorids such as Ampyx and Raphiophorus, save that the long spine that emanates from the glabella of the latter two genera has been modified into a knob-like or bulb-like structure in Bulbaspis that developed incrementally in the animal's growth.[1] The function of the bulb is as yet unknown: one hypothesis suggests sexual selection may have had a role in its evolution in the genus.[2]

Individuals of B. brevis, demonstrating development of the bulb

Bulbaspis Temporal range: Late Ordovician PreꞒ Ꞓ O S D C P T J K Pg N
B. mirabilis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	†Trilobita
Order:	†Asaphida
Family:	†Raphiophoridae
Genus:	†Bulbaspis Chugaeva, 1956
Type species
Ampyx bulbifer Weber, 1932
Species groups[1]
See text

Species

• ovulum group
  • B. lageniformis Zhou et al. 1982
  • B. ovulum Weber 1948
  • B. ordosensis Lu et al. 1976
• bulbifer group
  • B. brevis Zhou & Zhou, 2006
  • B. bulbifer (Weber, 1932)
  • B. korlaensis Zhang, 1981
  • B. mirabilis Chugaeva, 1958
  • B. sphaerornatus Chugaeva, 1958

See also

• List of trilobites

References

1. Zhiqiang, Zhou, and Zhou Zhiyi. "Late Ordovician trilobites from the Zhusilenghaierhan area, Ejin Banner, western Inner Mongolia, China."MEMOIR-ASSOCIATION OF AUSTRALASIAN PALAEONTOLOGISTS 32 (2006): 383. "Archived copy" (PDF). Archived from the original (PDF) on 2016-05-13. Retrieved 2016-01-12.CS1 maint: archived copy as title (link)
2. Knell, Robert J., and Richard A. Fortey. "Trilobite spines and beetle horns: sexual selection in the Palaeozoic?." Biology letters 1.2 (2005): 196-199.