Flavio
Mattavelli
Italian
version.
Marginella glabella & sebastiani Complex Atlas
(ex Quick reference guide).
I have
developed my ideas regarding the Marginella
glabella Complex. Today I believe it is possible that there are some hybridogenic categories in
it, that is some kleptons.
Yet I have
left unchanged, as archives, some pages regarding the varieties previously
thought only as varieties of species, without reference to kleptons.
See many
pictures in the wide & exaustive article "La variabilità fatta specie"
(3 archives pages only in Italian), regarding the
variability of Marginella glabella, M. irrorata, M. pseudosebastiani,
without klepton concept.
The
starting page is about the basic distinction between Marginella
glabella = G & Marginella irrorata
= I.
The second
page introduces Marginella glabella mutabilis
Mattavelli 2005, hybridation subspecies GXI.
The third
page regards Marginella
glabella antinea & problematica.
By writing
"species" I mean a biological category which
may be either a true species or a true klepton.
O
= Marginella goodalli Sowerby, 1825, Senegal, specimens 35 mm and
28 mm length, true species.
Marginella goodalli is unmistakable, except for with some
"stocky & dark" forms of M. sebastiani.
S = Marginella sebastiani
Marche-Marchad & Rosso, 1979, true species. Different varieties:
S = mixed & elongate,
nearly typical “sebastiani",
further divisible in different sub varieties, not pictured.
It's shown a particular specimen,
Guinea, 52 mm.
These forms are confusable with M.
pseudosebastiani; to distinguish them, see "The
discriminating factor", mainly in M. sebastiani
note the absence of subsutural axial flames.
F = "sebastiani lellia" varieties,
in honour to my wife Lella.
There are 2
basic sub varieties of “lellia”,
represented specimens 40 and 40 mm length, vinated
body, toothed adult specimens, with large light spots on the livery:
left “lellia
tondapex”,
right “lellia
acutapex”.
There are also “stocky & dark” varieties, like as
the 2 next “sebastiani lellia acutapex”, 45 and
38 mm:
P
= Marginella pseudosebastiani Mattavelli 2001, the biggest specimen of
the sintypes, 64,4
mm length, typical form. Also see: the links page.
Clarification concerning M.
glabella atlantidis Buey Suarez, 1980.
This marginella
was then named M.
pseudosebastiani Mattavelli, 2001 new species.
Buey
Suarez (in an article of the magazine La Conchiglia,
Rome, n ° 138/139 September / October 1980, Evolver edizioni)
identified a form "glabella gigas" calling it "glabella atlantidis", without
separating it as a new species. Instead it is a very
different species from M. glabella.
Direct comparison between
Marginella sebastiani
& Marginella pseudosebastiani.
On the left Marginella pseudosebastiani Mattavelli 2001, 58,4 mm, sintype.
On the
right Marginella sebastiani Marche-Marchad
& Rosso 1979, 59,6 mm, "elongate" form.
G = Marginella glabella (Voluta glabella Linneus, 1758-1767; Genus Lamarck, 1799). True species, type of the Genus Marginella.
There are many
and very variable subspecific forms of Marginella glabella that can be confused with M. irrorata.
For the basic identification of these 2 species, I
refer to my article "The variability made species"
(only Italian language, 2005-2006), where, however, I did not suppose the
possible existence of klepton, nor of M. pseudoglabella
or of M. visayae yet.
In 2021 I analyzed different morphological forms
of glabella-like etc., looking for a more appropriate
classification. The livery of G is very variable, with shells
usually between 30 and 50 mm length. The distribution is generally West Africa,
from Morocco to Senegal, however it would be better to investigate the places
of origin and the bathymetry of all the individual
numerous varieties.
The
6 specimens depicted are almost typical of M. glabella,
2 more colored, 2 almost "albino" and 2 intermediate forms with
degrading liveries towards a light background. Personally
I consider the intermediate liveries to be typical, as the more colored ones
may, on the other hand, encroach on the burgundy typologies of the morphs of
some M. pseudoglabella,
which however are also more elongated and, in adults, larger in size (see Links
page and definition of “pseudoglabella”).
I remember the presence of some forms that
before were all G mutabilis
and G antinea, but now they should
instead converge in part mostly in M.
visayae and in a minimal residual part remain forms of G. Some morphs of M. glabella show notable tendencies of
morphological hybridization towards M. irrorata, to be assumed the
existence of a form M.
glabella mutabilis. The "mutabilis"
variety could perhaps even be a form of a possible hybridogenetic
klepton between M. glabella X M. irrorata. However, since
there is a clear biological separation between these 2
species, I think this klepton is unlikely, while the
identification of almost all "mutabilis" with "visayae" is highly probable.
Genetic analyzes of molluscs are needed to settle the
issue.
In the Canary
Islands M. glabella is
smaller, namely dwarf glabella, like as this other 6 specimens ,
from 25 to 30 mm length, Lanzarote Island, depth - 20 m, sand
soundings. The small “glabella” of
the Canary Is. can also be well confused with M. irrorata and M. velai,
especially if in “albino” forms.
The cases of "albinos" complicate the
Complex specific situation.
On the
left M. glabella albida, "albino",
35 mm, Mauritania, where “albida” constitute entire populations of so-called
"albinos", or better leucistic forms, if not different
species or klepton. If
they not are different species, or varieties of species, they could be kleptons.
In other species of the Complex I think "albinos" are rare, however
they may exhist. The "albinos" are mostly
in the species M. glabella & irrorata and
in their "hybrids". The exact biological category is to be
investigated.
The various similar "albida" forms
really could be in alternative or a form of the species M. irrorata or of the species M. glabella, or they
could be at a time a new species too, to be defined
genetically.
In the article Revisione di
glabella I considered the forms “irrorata albinea”, unclassifiable “tizianica” and M. mattavellii
Cossignani, 2021 new species.
I = Marginella irrorata Menke, 1828, true species.
I = Marginella
irrorata irrorata,
25 mm, "almost albino". Usually
M. irrorata is pink, see "La variabilità fatta specie".
By morphology it is very difficult to distinguish M.
irrorata from M. glabella. Generally M. irrorata is under 30 mm length. The mollusk
is different but the shell is similar. I think that most "irrorata gigas"
on sale with exceptional size (40 mm) are simply varieties of M. glabella, or more likely varieties of M. visayae.
T = Marginella
irrorata pseudoirrorata Mattavelli, 2017.
Specimen 21,5 mm, West Sahara,
strangerly amber-coloured.
Usually the background colour verges on amaranth.
The light
spots may be well located in M. irrorata variety
pseudoirrorata.
Some
consider “pseudoirrorata”
a separate species, above all due to the presence of decidedly “cheetah” dots
with a regular screen.
V = Marginella (kl.?) visayae Mattavelli, 2021. In October 2021 I
introduced M. visayae in MMM magazine, n °
113, p. 36/41, as a possible "sibling species" of G & I. Some
"G mutabilis"
and "G antinea",
varieties so called by me in 2005, then understood as intermediate
forms of M. glabella
towards M. irrorata
and M. pseudosebastiani,
are now considered M.
visayae.
Holotype of V, 41 mm length, deposited at the
Malacology Museum of the World Exhibition, Cupra
Marittima.
The holotype is characterized by an ultra-fine clear speckling, which is
best distinguishable with a magnifying glass.
Today I identify the majority of the
"antinea"
and "mutabilis"
morphs as varieties of the "visayae"
species, see article Revisione
di M. glabella, 2021, as
well as the definitive article on "visayae".
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There are also specimens with coarser dots, called M. visayae pseudovisayae. The one shown, 41.4 mm long, is part
of a syntypical series presented in an
introductory article by "visayae",
where in 2018 the specimen was declared "ex antinea".
Some other morphs of "antinea" or
"mutabilis"
could still be identified as klepton,
not well specified morphologically (GXP? Or GXI?), perhaps also converging
towards M. (kl.?)
pseudoglabella = L and/or towards M sebastiani =
S, in addition to the hypothetical supposed hybridizations GXP and GXI.
W = Marginella
velai Ahuir Galindo
& Tiziano Cossignani, 2020.
In July
2020, a new species, of which this specimen is almost typical, was introduced in issue 108 of the magazine MMM
(Malacology World Exhibition of Cupra Marittima).
Average length of the various paratypes about 30 mm,
place of origin Morocco. The species can be confused with some already known
species of the Marginella glabella Complex, intended to include Marginella irrorata Menke, 1828 and even Marginella lamarcki Boyer, 2004. Detailed
discussion in article 5 confusing glabella-like
and irrorata-like
marginellas.
L = Marginella
(kl.?)
pseudoglabella Mattavelli, 2018 new species.
The photo of the side specimen (n °
926624) is owned by Conchology Inc., a Web site where similar morphs were all
referred as "lamarcki cf.", that is
to compare with M. lamarcki, although the true
species Marginella lamarcki Boyer, 2004 is much smaller
and different, framable out of the M. glabella
Complex, and therefore here neglected.
The specimen of the photo is from Senegal. It is 50.1 mm long and belongs to
the series of sintypes of the new "species"
M. (kl.?) pseudoglabella.
I refer to it as a new biological category of clear morphology, different from
the previous species, but of dubious biological nature, probable klepton of hybrid morphology GXS, with a tendency to PXS;
anyway with a different morphology both from G, S, P and I.
The other approximately 30 sintypes of Conchology Inc. range from 46 to 68.8 mm shell
length.
The topic was first discussed in the Universo lumperia
article and then on the Complex Links page.
For considerations that I hope will be conclusive, see the article New
look at the worlds of M. glabella & pseudoglabella,
finally Descrizione
comparativa della nuova “specie” Marginella (kl.?) pseudoglabella
Mattavelli, 2018.
E = Marginella
(kl.?)
pseudoglabella lellae
Mattavelli, 2018, perhaps a new "species", not common.
The specimen on the side is 52.5 mm
long.
It is characterized by a regular
dotting of the livery, analyzed in the article A leap into the "cheetah" shell nets.
Be careful not to confuse the name
with the forms M. sebastiani
lellia = F, analyzed in
the article Marginella
sebastiani in its 5 main varieties.
Morphologic "hybrids" of
GXP or GXS or PXS, or GXL or PXL or SXL. Note that the term "hybrid"
frequently is used only with a morphological purpose, but the introduction of
the klepton concept (hybridogenetic
hybrid) upsets any identification based only on the biological species concept,
or species varieties (and their sterile hybrids) concepts.
There may also be hybrids of M. visayae & irrorata, etc., but they are not
considered here for simplicity.
The Complex of the
"species" G, P, S, L is morphologically hybridable with difficult identification of some forms of
the single species or their "hybrids". The apparent hybrids are
mostly referable to a single one of the species, but in some cases that is
almost impossible.
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On the left example of doubtful
form, verso & recto 43 mm length, Nouadhibou,
Mauritania, 1,87 total stretch, juvenile specimen, because of the thin lip. If it is not probably a
specimen of M. pseudosebastiani, I think it is a klepton, maybe PXG, or PXS, or PXL.
An identification with only typical
L is not acceptable, because the mouth of the shell is too
lengthened.
However an identification is
possible with an atypical variety of M. (kl.?) pseudoglabella, or with
one of its "hybrids", among LXG, or LXS.
In other cases
there are also few morphological hybrids that can be estimated M. glabella X M. sebastiani
and it may seem easy to attribute them only to one or the other species. In
reality, this is not easy at all.
R= Marginella
pseudodesjardini Le Béon, 2012. It
is longer and more coloured than typical M. pseudosebastiani.
M. pseudodesjardini is coloured as M. sebastiani and on the contrary
it presents the subsutural axial flames.
Besides M.
pseudodesjardini is generally less elongate than M.
desjardini and with different pattern, with clear
spots in the clear bands around the shell.
typical form "pseudodesjardini", pictures from
the
"Synthese" of Roger Le Béon
2008.
The typical form appears as a
"hybrid" S X D; denomination ex and alias
synonymous of the form "incredibilis"
Mattavelli 2011.
form “giselica” Mattavelli 2013, Senegal, 73,5 mm length (Gisela's pictures).
It could be or a
variety of M. pseudosebastiani, but
more probably it is a variety of M. pseudodesjardini,
or less probably a true hybrid or a possible klepton
P X D or P X R. The adult form "giselica"
has the margin towards the shell mouth smooth, while "typical pseudodesjardini" has the same margin finely serrulated.
D = Marginella desjardini Marche-Marchad, 1957, Guinea, 59,6 mm length, true species.
Table of approximate
average total shell lengths and shell elongations (= stretches).
Observe that the average
lengths are not arithmetic, but the average is shifted
towards the maximum lengths for the specimens of the small species and towards
the minimum ones for the specimens of the large species. Tot. elongation = Tot. length
/ Maximum diameter including the expansion of the shell margin.
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Extended
Complex graph.
Being able to
easily separate the species M. goodalli
and M. desjardini and considering M. irrorata
biologically well different from M.
glabella (but non morphologically), in 2001 I proposed a Marginella glabella & sebastiani
Complex in the strict sense, by including in this Complex also the
species M. pseudosebastiani
for shell affinities, but excluding all other species which are also very close
to G, S, P.
Undoubtedly we must also take into account the neighboring species, better meaning a Marginella
glabella & sebastiani Complex extended to
all known species morphologically similar to G, S, P, including the latest
"discoveries", but I neglected
M. visayae, which has an amoeboid
morphology.
Besides in the next graph I neglected the small sp. M. aurantia, lamarcki, mattavellii, velai, etc. mentioned in the Appendix regarding M. sebastiani
with my synthetic symbology.
Some species and some of their
varieties have been set in the drawing by comparing the size of the shell and
the distribution of the livery dotting. The most evasive species as to
morphological identification is in the bottom left (M. irrorata), while, increasing the
coordinates, the identification of the varieties appears facilitated by the
size and livery of the shells.
Note: the
size of the dots and the size of the shells are chosen
as Cartesian coordinates, but some other morphological characteristics could be
chosen. For example we could choose on the abscissa the total stretch = maximum
length / last round diameter, or the mouth stretch = shell length / maximum
mouth width, and on the ordinate the subsutural flammulation,
or the profiling of the shell or of the single loop.
They are evanescent topics, but
partially quantifiable with one of the previous stretches, adding other treacherous
concepts, such as the curvature of the loop and the last turn, and
mathematicising the curvatures with the introduction of the measures of the
various angular determinants, identifiable in the profile of the shells, which
is practically impossible.
By changing the reference
coordinates, the mutual positions of the species and their varieties in the
design could change, however they would always remain in conditions of relative
proximity between the species and their most similar varieties.
Flavio Mattavelli
Update 25/09/22. Non-profit
reproduction authorized only citing the sources and names of the respective
Authors of the images. If necessary, I recommend printing with minimum margins
(9 sheets A4).
Home. Italian
version of this article.
The site is divided into 4 Sections
(Shells,
Machines,
Aeromodelling,
Gorgonzola),
for a total of 51 pages in 2022. The individual
sectional pages are accessible by linking the Homes of the individual Sections.
All pages are also accessible from
the general
index.
Green
in English, a list of
24 sectional pages (including this one), regarding Shells Section only.
- Introduction
(only in Italian language)
- Specie/klepton Concepts, 2016 update.
- Marginella pseudosebastiani Mattavelli, 2001, versus M. sebastiani & glabella Complex, 2006 archives
- Atlante
delle specie attuali del Marginella glabella Complex e di alcuni loro ibridi
morfologici, 2022.
- Marginella glabella & sebastiani Complex Atlas (present page, ex Quick reference guide). 2022.
- Analysis of 5 confondibili marginelle simil-glabella. Release 18/02/2021.
- “La variabilità fatta specie”
article, part 1, to be revised, regarding M. glabella & irrorata.
- “La variabilità fatta specie” article, part 2, to be revised, regarding M. glabella mutabilis.
- “La variabilità fatta specie” article, part 3, to be revised, regarding M. glabella antinea.
- Other kleptons in the Marginella
glabella Complex? With photografic table. 2017 update.
- Marginella pseudodesjardini Le Béon, 2012 new species. Notes on the different "pseudodesjardini giselica" Mattavelli, 2013 form.
- Universo lumperia. Morphologic hybrids SXP and SXG. Possibility of the new M. (kl.?) pseudoglabella Mattavelli, 2014 hypothesis.
- “pseudoirrorata” 2017, variety of Marginella irrorata.
- Complex links. 2020 remake. Hypothesis of “pseudoglabella”, 2018 new species.
- Links solo in italiano con postilla “La bocca della verità”. Release 2020.
- Nuovo sguardo ai mondi di M. glabella e M. (kl.?) pseudoglabella, this is supposed new species or klepton in 2017
- Descrizione comparativa di Marginella (kl.?) pseudoglabella Mattavelli, 2018 nuova "specie"
- Marginella (Kl.?)
visayae Mattavelli, 2018, supposed new “species” or klepton, with description of the “varieties” M. pseudoglabella lellae
& M. irrorata pseudoirrorata.
- Marginella (kl.?) visayae Mattavelli, 2021 new species, “sibling species”
of M. glabella & M. irrorata.
- M. glabella Revision, with proposals of my new denominations of its varieties (M. glabella glabella & M. glabella neoglabella)
- "Albinism"
of the species similar to M.
glabella & M. irrorata, with hypotheses, only on
Internet, of 2 new "albino species" (M. albida & M. tizianica)
- "Albinism"
in general, even for species not belonging to the M. glabella & sebastiani Complex.
- Un salto nei retini conchigliari “ghepardici”.
- Marginella sebastiani nelle sue 5 varietà principali.