Taxacom: Calcisphaera Williamson, 1880 - microfossil incertae sedis (Calcitarcha) or charophyte?

[Tony Rees]

For completeness, Miller's designation of robusta as the type is available
here:
https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.biodiversitylibrary.org%2Fpage%2F53798805&data%7C02%7Ctaxacom%40lists.ku.edu%7Cc90e72eceeaa457ae63108dddbcb4f8f%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638908388470256559%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=O%2BVL4CKBXRg0eUiE7yCt%2B%2FWO161zgNxjiMFq3xjJpWU%3D&reserved=0

With hindsight (though probably of no nomenclatural significance) this
would seem possibly to be because robusta was the only species described
from North America (the scope of Miller's book); Williamson admitted this
species to his genus on being sent some material, at the end of his
description of the specimens he himself had collected, on which the
remainder of the genus was based, which were from Wales.

Williamson wrote:
"I would call attention to some specimens, myriads of which constitute
almost the mass of a ? Corniferous limestone? from the Devonian beds of
Kelly?s Island, U.S.A., for specimens of which I am indebted to Mr. Brady,
and which we both believe to be closely related to the Welsh organisms
... Occasionally these ridges may be seen pursuing an oblique direction
like the bands crossing the nucules of a Chara ... Though the sphere-wall
often exhibits a granular texture, I discover a radiating structure in a
sufficient number of the specimens to convince me that, in this respect,
they have closely resembled some of the Welsh objects. Since I cannot learn
that this American form has received a name, it may be designated
Calcisphaera robusta."

So the only one from North America, that also had some features of a
charophyte, became Miller's type, leaving the others potentially
misclassified...

- Tony


On Fri, 15 Aug 2025 at 15:51, Tony Rees via Taxacom <taxacom at lists.ku.edu>
wrote:

> I am seeking an answer as to whether the calcified microscopic fossil genus
> Calcisphaera Williamson, 1880 (treated mainly as a botanical form) should
> be treated as a microfossil incertae sedis (Calcitarcha) or assigned to
> charophyta (as representing a charophyte spore aka gyrogonite). Williamson,
> 1880 originally assigned 7 species to the genus but failed to designate a
> type; of these, C. laevis (and possibly all of the others but one) is today
> considered a calcisphere microfossil in the group Calcitarcha, while C.
> robusta is considered a charophyte spore. The correct assignment of the
> genus therefore turns on which species is considered the type.
>
> Andrews (1955 and 1970) in "Index of Generic Names of Fossil Plants" gives
> the type as C. laevis, however Index Nominum Genericorum gives the type as
> C. robusta following Miller, 1889 who designated that species as the
> lectotype. Apparently Andrews' designation (which was subsequently
> supported by Peck & Morales, 1966 and Grambast-Fessard et al., 1989)
> followed "Article PB. 4 of the [then current] International Code of
> Botanical Nomenclature" which states: "The type of a genus of fossil plants
> is the first described species which shows such characters as are necessary
> for distinguishing the genus from other taxa."" (that text from Peck &
> Morales, 1966), thus according to that logic, Miller's designation of C.
> robusta as the type was not only unnecessary but invalid.
>
> However subsequently Samoilova, 1985, in a proposal to Taxon, recognised
> Miller's designation of C. robusta as the type and treated Calcisphaera as
> a charophyte genus, with apparent priority over another genus, Trochiliscus
> Karpinsky, 1906, if the two genera are treated as synonymous. Bu in a
> response to that proposal, Grambast-Fessard et al., 1989 stated: "The taxon
> Calcisphaera has not been retained [in Charophyta] as it includes species
> belonging to distinct taxonomic units; the first one described, C. laevis,
> designated as the type species, is not a charophyte but belongs to the
> animal kingdom (Peck and Morales, 1966: 314)."
>
> Later, Versteegh et al., 2009, on formally proposing the group Calcitarcha,
> noted the earliest forms to be those described by Williamson, 1880
> as Calcisphaera, and included that genus name in their list of Calcitarcha
> genera without further comment regarding its typification.
>
> Currently AlgaeBase offers a confused statement: it recognises Calcisphaera
> as a charophyte, with C. robusta as type species, but references
> Grambast-Fessard et al., 1989 as the most recent treatment followed (in
> fact as stated above, those authors state the exact opposite).
>
> So the question arises, does the current (or perhaps even a former)
> botanical Code support Peck & Morales, 1966 assertion that in fossil plants
> where no type is selected, the first mentioned species automatically
> becomes the type? That statement appears to originate in the Paris Code
> (1956), probably also in the 1952 Code, which indeed states:
> "Article PB. 4. The type of a genus of fossil plants is the first described
> species which shows such characters as are necessary for distinguishing the
> genus from other taxa. The type of a species of fossil plants is the first
> described and figured specimen showing such characters as are necessary for
> distinguishing the species from other species." (
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.iapt-taxon.org%2Fhistoric%2F1956.htm&data%7C02%7Ctaxacom%40lists.ku.edu%7Cc90e72eceeaa457ae63108dddbcb4f8f%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638908388470293374%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=9omyZrT4mk43h993yOlkPZdONdIJX0QK6gkgZVGdqxo%3D&reserved=0)
>
> So Andrews in 1955 would (according to my reading) be correct in using C.
> laevis as the tye species and ignoring Miller's subsequent designation of
> C. robusta.
>
> However I am not sure that is the situation today; the current ICNafp does
> not seem to contain this Article or wording; the nearest I can find (which
> is not specifically dealing with fossil plants is:
> 10.5. The author who first designates (Art. 7.10, 7.11, and F.5.4) a type
> of a name of a genus or subdivision of a genus must be followed, but the
> choice may be superseded if the author used a largely mechanical method of
> selection (Art. 10.6). A type chosen using a largely mechanical method of
> selection is superseded by any later choice of a different type not made
> using such a method, unless, in the interval, the supersedable choice has
> been affirmed by its adoption in a publication that did not use a
> mechanical method of selection.
>
> (A "mechanical method of selection" appears to comprise taking the first
> species listed).
>
> So where does this leave us? Is C. laevis or C. robusta the correct type
> for this genus, and accordingly, is it to be treated as Calcitarcha or
> Charophyta? (If indeed it is to be placed as a charophyte, then C. laevis
> and other similar species would require a new generic name in order to be
> placed in the Calcitarcha).
>
> Your answers appreciated,
>
> Regards - Tony Rees, Interim Register of Marine and Nonmarine Genera
> https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.irmng.org%2F&data%7C02%7Ctaxacom%40lists.ku.edu%7Cc90e72eceeaa457ae63108dddbcb4f8f%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638908388470313783%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=Dg7tn6Mt6ApVxl5qD77eYpwLCH8Jp1m8TaGwPnYbNFs%3D&reserved=0
>
>
> References in chronological order:
>
> Williamson, W.C. (1880). On the organization of the fossil plants of the
> coal-measures.?Part X. Including an examination of the supposed
> radiolarians of the carboniferous rocks. Philosophical transactions of the
> Royal Society of London 171(2): 493-539, plates 14-21.
> Available at
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Froyalsocietypublishing.org%2Fdoi%2Fepdf%2F10.1098%2Frstl.1880.0014&data%7C02%7Ctaxacom%40lists.ku.edu%7Cc90e72eceeaa457ae63108dddbcb4f8f%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638908388470335123%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=%2BZ7XXCJziP6vvSe2vCJjATI98Mw6d%2BcyHz5NQWiH3sE%3D&reserved=0
>
> Miller, S.A. (1889). North American geology and palaeontology for the use
> of amateurs, students, and scientists. pp. 664, 1194 figures. Cincinnati:
> Western Methodist Book Concern.
>
> Andrews, H.N. (1955). Index of generic names of fossil plants, 1820?1950.
> U.S.. Geological Survey Bulletin 1013: 1?262
>
> Peck, R.E. and Morales, G.A. (1966). The Devonian and Lower Mississippian
> charophytes of North America. Micropaleontology, 12(3), pp.303-324.
> doi:10.2307/1484549
>
> R. B. Samoilova (1985). (781) Proposal to Conserve Trochiliscus against
> Calcisphaeria and Moellerina (Fossil, Trochiliscaceae). Taxon, 34(1),
> 157?158. doi:10.2307/1221585
>
> N. Grambast-Fessard, M. Feist and Z. Wang. (1989). Concerning Rejected
> Proposal 781 to Conserve Trochiliscus (Fossil Charophyta). Taxon, 38(4),
> 641?643. doi:10.2307/1222654
>
> Versteegh, G.J., Servais, T., Streng, M., Munnecke, A. and Vachard, D.
> (2009). A discussion and proposal concerning the use of the term
> calcispheres. *Palaeontology*, *52*(2), pp.343-348.
>  doi:10.1111/j.1475-4983.2009.00854.x
>
> AlgaeBase (2025). Calcisphaera W.C. Wiiliamson, 1880:
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.algaebase.org%2Fsearch%2Fgenus%2Fdetail%2F%3Fgenus_id%3D53072&data%7C02%7Ctaxacom%40lists.ku.edu%7Cc90e72eceeaa457ae63108dddbcb4f8f%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638908388470352981%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=yhM%2BemGrjfWewzJTOwUKAX%2BuHLllF18B9Pnikf8cRRs%3D&reserved=0
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