Specimens of Halobia making up the “fossil staircase” at Princeton Castle, British Columbia, photographed by Joe Mabel.

Belongs within: Pteriomorphia.

Halobia was a genus of flat clams found worldwide during the Middle and Upper Triassic. Several species are useful index fossils for determining formation ages.

Characters (from Cox et al. 1969): Semicircular or ovate, with long hinge margin; rarely appreciably oblique; anterior wing clearly delimited on each valve, commonly by groove; ornament of closely and irregularly spaced narrow radial threads or grooves and of concentric folds, threads, which in many species are most developed on posterior side, increasing by bifurcation; ligament area striated longitudinally, but rarely observable.

    |--H. areataKI70
    |--H. arthaberiKI70
    |--H. austriacaKI70
    |--H. beyrichiKI70
    |--H. bosniacaKI70
    |--H. fallaxK79
    |--H. kwaluanaKI70
    |--H. landlensisKI70
    |--H. lenticularisKI70
    |--H. lepsiusiKI70
    |--H. marmoreaKI70
    |--H. noricaK79
    |--H. plicosaK79
    |--H. richthofeniKI70
    |--H. styriaca (Mojsisovics 1874) [=Daonella styriaca]KI70
    |--H. substyriaca Chen 1964KI70
    |--H. tobensis Kobayashi & Masatani 1968KI70
    |--H. yunnanensis Reed 1927 [=H. cassiana var. yunnanensis]KI70
    `--H. zitteliT81

*Type species of generic name indicated


Cox, L. R., N. D. Newell et al. 1969. Treatise on Invertebrate Paleontology pt N. Bivalvia vol. 1. The Geological Society of America, Inc. and The University of Kansas.

[KI70] Kobayashi, T., & T. Ishibashi. 1970. Halobia styriaca, Upper Triassic pelecypod, discovered in Okinawa-jima, the Ryukyu Islands. Trans. Proc. Palaeont. Soc. Japan, N. S. 77: 243–248.

[K79] Kummel, B. 1979. Triassic. In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A351–A389. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[T81] Tozer, E. T. 1981. Triassic Ammonoidea: geographic and stratigraphic distribution. In: House, M. R., & J. R. Senior (eds) The Ammonoidea: The evolution, classification, mode of life and geological usefulness of a major fossil group pp. 397–431. Academic Press.

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