Dr. Rob Dillon, Coordinator

Tuesday, September 28, 2004

Goniobasis and Elimia

The freshwater ceritheacean family Pleuroceridae is generally reckoned to encompass seven North American genera. Although the names for six of these genera are widely agreed upon, the name of the largest genus has become controversial in the last 20 years. Here I review the history of the genus name Goniobasis and its recently resurrected synonym, Elimia. I conclude that Elimia should have been suppressed, but that at this juncture the loss of either name would result in more confusion than retaining both.
  1. The genus Elimia was proposed by H & A Adams (1854) without type designation. Since the 16 species contained in the genus were extremely diverse, including what today would be recognized as three different genera (Goniobasis, Pleurocera, and Lithasia), the genus was not accepted by contemporary workers. It was specifically rejected by Haldeman (1863).
  2. The genus Goniobasis was proposed by Lea in 1862 with a description sufficient to distinguish the group.
  3. The first monograph of the American Pleuroceridae ("Strepomatidae") was that of Tryon (1873). He recognized Goniobasis as a natural group. Regarding Elimia, he wrote: "We quote the full lists of species given by Messrs. Adams, in order that the insufficiency of their genera may become more apparent from the incongruous assemblage of shells of which they have composed them." (pg xii)
  4. Pilsbry & Rhoads (1896) revived Elimia, designating acutocarinata as type by virtue of its first listing in the alphabetical arrangement of H & A Adams. But Pilsbry used Goniobasis for the three species of that group covered in his 1896 paper, and in many subsequent papers (e.g., Pilsbry 1916). He himself never used the genus Elimia.
  5. Hannibal (1912) designated osculata (Lea 1862) as the type species of Goniobasis.
  6. The North American mollusks were reviewed by Walker (1918). Walker used Goniobasis, writing (Pg 149): "Dr. Pilsbry has more recently decided that Goniobasis should be restored to its former position as a generic term, on the ground that Elimia was a composite group."
  7. The family Pleuroceridae was next monographed by Goodrich, in a series of papers published from 1922 - 1944 (e.g., 1936, 1940, 1942). Goodrich used Goniobasis. Although the literature continued to contain occasional references to Oxytrema (Raf.) and rare uses of Elimia, almost all workers followed Goodrich through the next 50 years.
  8. The literature contains, I believe, about four or five instances of the genus Elimia between 1918 and 1978 in total. I would estimate the usage of Goniobasis during this 60-year period to be one or two per year. A review of the Zoological Record 1970 - 1979 shows 13 instances of Goniobasis, 3 of Oxytrema, and none of Elimia.
  9. Burch (1979) resurrected Elimia for his (1980, 1982) monograph "North American Freshwater Snails." He wrote (1982:271), "Elimia H & A Adams 1854 is used in place of its better known synonym Goniobasis Lea 1862." Burch (2001) subsequently added, "Since Elimia H. & A. Adams 1854 has clear priority over Goniobasis Lea 1862, an appeal could have been made by me (or someone else) to the International Commission on Zoological Nomenclature in an attempt to conserve the name Goniobasis. But having knowledge of - and in fact participating in - the long battle to get the genus name Pleurocera conserved to fit its common usage convinced me that such an endeavor to save the use of the junior synonym Goniobasis would be futile, and in any event would take an inordinate amount of time, and certainly try the patience of malacologists."
  10. No consensus has followed. The Zoological Record for the period 1980 - 1989 reported 29 uses of Goniobasis and 9 uses of Elimia, and for the period 1990 - 2000 reported 10 uses of Goniobasis and 37 uses of Elimia. The classification of Vaught (1989) used Goniobasis, and that of Turgeon et al. (1998) used Elimia. The U.S. Endangered species list uses Elimia.
As the clear choice of Haldeman, Tryon, Pilsbry, Walker, Goodrich, and almost every other professional malacologist for over 100 years, the nomen Goniobasis has been attached to a great and valuable literature. The nomen Elimia, which should have been suppressed 25 years ago, has nevertheless also become attached to a significant literature. The loss of either name at this point would be unconscionable. Thus it seems to me that both names ought to remain in currency, and that authors preferring Goniobasis should refer to "Elimia" in their text, while authors preferring Elimia also refer to "Goniobasis."

Those of us who are familiar with the English language have come to accept, in fact even expect, synonyms. If I ask for or request a soda or a pop with my hot dog or frank I will get or receive the same thing. Synonyms are a stable component of daily communication, and do not necessarily lead to confusion. So regarding Goniobasis or Elimia, as my daughter used to say, "Whatever!"


Adams, H. and A. Adams. 1853 - 58. The genera of recent Mollusca; arranged according to their organization ( 3 Vols.). John Van Voorst, London.
Burch, J. B. 1979. Genera and subgenera of Recent freshwater gastropods of North America (North of Mexico). Malacological Review 12:97-100.
Burch, J. B. 1982. North American freshwater snails: identification keys, generic synonymy, supplemental notes, glossary, references, index. Walkerana 4:1-365.
Burch, J. B. 2001. On the genus name Goniobasis (Elimia - Gastropoda: Pleuroceridae) and other recent nomenclatural inconsistencies. Walkerana 12:97-105.
Burch, J. B. and J. Tottenham. 1980. North American freshwater snails: species list, ranges, and illustrations. Walkerana 3:1-215.
Goodrich, C. 1936. Goniobasis of the Coosa River, Alabama. Misc. Publ. Mus. Zool. Univ. Mich. 31:1-60.
Goodrich, C. 1940. The Pleuroceridae of the Ohio River system. Occas. Pprs. Mus. Zool. Univ. Mich. 417:1-21.
Goodrich, C. 1942. The Pleuroceridae of the Atlantic coastal plain. Occas. Pprs. Mus. Zool. Univ. Mich. 456:1-6.
Haldeman, S. S. 1863. On Strepomatidae as a name for a family of fluviatile Mollusca, usually confounded with Melania. Proc. Acad. Nat. Sci. Phila. 15: 273 - 274.
Hannibal, H. 1912. A synopsis of the Recent and Tertiary freshwater Mollusca of the California Province, based upon an ontogenetic classification. Proc. Malacol. Soc. Lond. 10:112-211.
Lea, I. 1862. Description of a new genus (Goniobasis) of the family Melanidae and eighty-two new species. Proc. Acad. Nat. Sci. Phila. 14:262-272.
Pilsbry, H. 1916. Goniobasis in western Pennsylvania. Nautilus 30:4-5.
Pilsbry, H. and S. Rhoads. 1896. Contributions to the Zoology of Tennessee, Number 4, Mollusca. Proc. Acad. Nat. Sci. Phila. 1896:487-506.
Tryon, G. W., Jr. 1873. Land and Freshwater Shells of North America. Part IV, Strepomatidae. Smithsonian Miscellaneous Collections, vol. 253. Washington, DC.
Turgeon, D., J. et al. 1998. Common and Scientific Names of Aquatic Invertebrates from the United States and Canada: Mollusks. Special Publications, vol. 26. American Fisheries Society.
Vaught, K. 1989. A Classification of the Living Mollusca. American Malacologists, Melbourne, FL.
Walker, B. 1918. A Synopsis of the Classification of the Freshwater Mollusca of North America, North of Mexico. Misc. Pubs., vol. 6. University of Michigan Press, Ann Arbor.