Dear Simon,

What a problem you have here!

Petit (2009: 72) cites the first usage of Macroschisma to be of Gray
[in G.B. Sowerby I (1835: 80)], who included only Fissurella
macroschisma "Humphrey," making that taxon the type by monotypy.
Petit goes on to state that Patella macroschisma Lightfoot, 1786 is
the first validation of the binomen.Lightfoot (1786: 71)* described
the Dutchess of Portland's lot no. 1601: "An extremely fine pair of a
species of perforated Patella, the only two that are known, named
Macroschisma, Humphreys's Conch. Plate 7, fig.. 3."  Rehder (1967:
14) discussed this taxon at some length, concluding that "Humphrey"
[actually this anonymous work is properly attributed to E M. da Costa
(1770-1772)] indication, which lacked text, and the Lightfoot
description were insufficient to make Patella macroschisma of either
da Costa or Lightfoot available, and he deemed it a nomen dubium.
Thus Macroschisma Gray in G.B. Sowerby I is currently unavailable. To
add another twist, Rehder added: "Not Patella macroschisma Holten,
1802, nor Dillwyn, 1817 (= Macroschisma maxima A. Ad., 1850)."

That's as much as I can handle at the moment, but clearly this will
be a long and convoluted analysis.

Best wishes in your quest,
Harry

*Lady Margaret Cavendish Bentinck, Duchess of Portland, died in 1785
leaving extensive and valuable collections, not the least of which
was of shells. The Rev. John Lightfoot (1735-1788), her librarian and
chaplain, compiled and annotated a list of her curios.   This 194
page, 4156 lot inventory was printed early the next year and served
as the catalog at the auction of her collections from late that May
to June 18 (Lightfoot, 1786;  Dance, 1966;  Kay,
1965;  Rehder,1967).  Allison Kay (1965; p. 10) gave convincing
evidence that Daniel Solander, a pupil of Carl Linnaeus, a naturalist
who curated material in the duchess's collection, first penned many
of the names employed by Lightfoot, but only in manuscript
form.  Until 1965 most attributions for the "Portland Catalogue"
nomina were to Solander, but, after Kay's report, the consensus among
malacologists is that Lightfoot is the proper authority.

Although a substantial number of zoological names were validly
proposed by Lightfoot in this "Portland Catalogue," only a handful of
workers in the 18th and 19th centuries put them to use, often without
proper acknowledgement. Even the work of Sherborn (1902; later
corrected), which purported to list all the zoological names
introduced from 1758 to 1800, listed none of these names.   Tom
Iredale was the first to specifically wrest the names from near
oblivion. William Healy Dall (1921) investigated the "Portland
Catalogue" mollusks and presented selections of the Lightfoot text,
which was always brief, but often cited an illustration in an earlier
work or two.


At 05:24 PM 11/11/2009, you wrote:
>Dear Conch-lers
>
>Can anyone help me on a point of detail?
>
>Is the correct name of the Fissurellid genus Macroschisma or
>Macrochisma or something else entirely?
>
>The Treatise on Invertebrate Palaeontology gives seniority to
>Macroschisma Sowerby, 1839, the type species being Patella
>macroschisma Solander, 1786 and lists Macrochisma Gray, 1840 as a
>junior synonym.
>
>Wilson, 1993 agrees with Macroschisma Sowerby, 1839, noting some
>confusion behind the origin of Sowerby's naming of the genus but
>retaining it all the same, in favour of the genera Foralepas and
>Dolichoschisma, both Iredale, 1940, which some consider as genera,
>some as subgenera and others, like Wilson, relegate to synonymy.
>Wilson doesn't mention Macrochisma at all.
>
>However, I am a little confused by Vaught, 1989 (Classification of
>Living Mollusca) who gives seniority to Macrochisma Sowerby, 1839
>and lists Macroschisma Agassiz, 1846 as a synonym. (Vaught goes on
>to treat Dolichoschisma Iredale, 1940 an erroneous spelling of
>Dolichischisma Iredale, 1940).
>
>Any thoughts would be welcomed.
>
>Simon Taylor
>United Kingdom

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