Flavio Mattavelli

Per la versione in italiano. This is an English version of the article:

Links to the Marginella glabella Complex,

especially regarding the “speciesMarginella pseudosebastiani Mattavelli, 2001 and Marginella (kl. ?) pseudoglabella Mattavelli, 2018, as well as the “varietiesMarginella irrorata (Menke, 1828) pseudoirrorata Mattavelli, 2017  and Marginella (kl.?) pseudoglabella lellae Mattavelli, 2017.


The biological categories of "species", "varieties" and "kleptons" are treated on the Species / klepton page.

This Links page was born before 2006, as a list of links to websites dealing with the new species M. pseudosebastiani = P.

In 2017 the discovery of M. (kl.?) pseudoglabella = L prevailed; the page became a concentrate of references mostly to L.

See the chapter New biological category (L) in the M. glabella Complex (Implications of P & S with G, inducing the morphology of L).

The existence of the unusually large morphs of M. (kl.?) pseudoglabella Mattavelli, 2018 upsets the structure of the Complex of G = M. glabella Linneus, 1758-1767, which is the type species of the Marginella Genus.


This Genus is often indicated with the abbreviation M., however often its "species / klepton" are indicated only in quotation marks, without indicating the Genus, thus contradicting a fundamental taxonomic rule, to the purpose of simplification, only for my internal use.

For a maximum abbreviation, I have even used and will use a synthetic writing with specific abbreviations (see forward the list).

To this purpose consider the normal capital letters in the same way as the capital letters in italics and / or in bold, while I have always tried to write in italics the extended names of the species / klepton.

To highlight the ambiguity of the new klepton category, sometimes I write the term "species", and the related terms, such as their "varieties", in quotation marks.


The original species of Linnaeus, always considered a "true glabella = G" type species, must be joined to a new separate biological category, ambiguous for science, that is, supported by either a new "sister" biological species, or a new klepton, "specific" category called "pseudoglabella", recognized as a true species in 2018.


Furthermore, the discussion could be expanded to a presumed further new "species" Marginella (kl.?) visayae Mattavelli, 2018, which, however, has not been recognized yet as a species or a klepton, but not even defined as a simple "variety" of an already known species / kleptons.

You can see my first hypothesis of klepton molluscs in the magazine Malacology World Exhibition, n ° 70, February 2011. I thank Messrs. Cossignani of the World Exhibition of Malacology - Cupra Marittima (http://www.malacologia.org or http: //www.malacologia.it ) for the publication concerning the supposed Marginella klepton pseudodesjardini (Le Béon 2008) Mattavelli 2011, today recognized as species M. pseudodesjardini Le Béon 2012.
For the hypotheses of klepton among the species M. pseudosebastiani, sebastiani, glabella, desjardini, pseudodesjardini & pseudoglabella see the page http://www.pseudospecie.it/Altriklepton.htm.
A summary was published in the MMM-Cupra Marittima magazine, n ° 74, February 2012, but this summary was revised in 2014 & 2017 on my above mentioned Internet page. The percentages, in the conclusion of the same Web article, must however be changed again for the introduction of the supposed M. (kl.?) visayae = V.


I have left out the fossil marginellas. I report the site of Maurizio Forli: http://www.dodoline.it/ .

This site does not deal in marginellas, but Forli is coauthor, together with Bruno Dell'Angelo, of Marginella misae, fossil species of Italian Pliocene, and not only (Bollettino Malacologico SIM, n° 36 (5-8), 2000, pages 93-98). 

M. misae is an ancestor of M. pseudosebastiani, pseudoglabella, etc.


Marginella pseudosebastiani links.

Marginella pseudosebastiani Mattavelli 2001, recto and verso, 64 mm length, largest sized sintype, in Mattavelli collection (picture by Eddie Hardy, of www.gastropods.com). The sintypes are partially in Mattavelli collection. 

The existence of the new species was perceived in 1995 and reported on line in 2000 in the SIM site (Società Italiana di Malacologia) and in CONCH-L ( http://listserv.uga.edu/cgi-bin/wa?A0=conch-l&D=0&F=&H=0&O=T&S=&T=1). In truth this first news remained unnoticed, but it is still in the correspective BBS archive (SIM 22/04/00) and mailing list (CONCH-L, September 2000).

In June 2001 I sent a "Comparative description" to www.seashell-collector.com (France), of David Touitou. This description and the picture of a sintype, 47,3 mm length, remained on his Web site for 2 years. 

A lectotype, 55 mm length, was deposited at Museum of Malacologia Mostra Mondiale of Cupra Marittima (Ascoli Piceno, Italy).

I thank Messrs. Cossignani of Malacologia Mostra Mondiale (http://www.malacologia.org/ or http://www.malacologia.it/) for publishing the description of the species P, in September 2001, n°34 magazine.  

The species "pseudosebastiani" is notified in the Zoological Record, based on ICZN, see ION (Index to Organism Names), and WoRMS (World register of marine species).

Basic description of "pseudosebastiani" in my Statements on the Complex, with particular reference to M. sebastiani.


Marginella pseudoglabella links.

The "species" L was defined in 2018 (MMM magazine n ° 99, April 1918, pages 29/30).

See the definitive and comparative study also on the Web, to which I warmly refer.

The signs of its existence date back to 2014, to the article Universo lumperia. For precise identification of "pseudoglabella" see the Notes regarding "lamarcki cf." of Conchology Inc. Web site, specimens which I have assumed as "pseudoglabella" sintypes.

As the discussion has dragged on since 2014, you will find some references to that year and 2017, but M. pseudoglabella, understood as a new species, should be exclusively referred to since April 2018.

In the article Nuovo sguardo ai mondi di Marginella glabella e pseudoglabella (New look at the worlds of Marginella glabella and pseudoglabella), dated 2017, I deepened further their correlations, also assuming that some bordeaux forms, considered in the past M. glabella forms, are instead forms of M. pseudoglabella, in most cases joung specimens.
The new
"pseudoglabella" category has not yet been recognized as an autonomous biological category (new species or klepton), yet "pseudoglabella" deserves  to be separated from the other species of the Marginella glabella Complex.

The morphs of adult and giant "pseudoglabella" are not common, but not very rare. They are quite different from each other, but they can be framed in the same "pseudoglabella" population, of which I own about a dozen specimens, precisely different from each other.

Photos of many other "pseudoglabella" specimens are spreaded across the many Dealer Web sites that deal with margin shells, but with incorrect identification names (sometimes as P, as S, as I and sometimes as G, symbols according to the synthetic writing proposed below).
To the general links of the websites recommended below, I added the incorrect names of the species given by the Dealers, by using the (*
synthetic abbreviation *), referred to photos that in my opinion are only of L (whenever L is erroneously indicated with the synthetic abbreviation enclosed in the asterisks).

Today some L could be even confused with V, but I have not considered that, because the identification of V is not very clear yet.

Besides the list of links dealing with L was updated in 2017 and at the time I did not think of V existence.

Therefore in this page I do not deal in detail with the numerous morphs of V = Marginella (kl.?) visayae Mattavelli, 2018; for which I refer to the additional page concerning T, E, V (only in Italian language).


Links regarding the margin species P, S, G, L & I, neglecting the possible new "species" V.

Sometimes there is a recall cfr.(or cf….) = to be compared with …(the name placed next to the reference).


P = Marginella pseudosebastiani Mattavelli, 2001

S = Marginella sebastiani Marche-Marchad & Rosso, 1979

G = Marginella glabella Linneus, 1758-1767

L = Marginella (kl.?) pseudoglabella Mattavelli, 2014? pseudoglabella will be published on the Web in 2017, and in paper in 2018.

L comprise the probablevariety E = M. pseudoglabella lellae Mattavelli, 2018

I  = Marginella irrorata Menke ,1828.

I comprise the probablevariety T = M. irrorata pseudoirrorata Mattavelli, 2017 


I notify some sites with an excellent list of general links & marginella pictures, although at present they could not contain pictures of all the specimens of P, S, G, L & I.

The identification of the marginellas is not always correct in the auctions on line, but they are very interesting.

http://www.shellauction.net/ (Italy), big site of Alessandro Petronzi e Claudio Pirazzini.

http://seashell-collector.com/links/page_internet-resources.html, of David Touitou.

http://www.shelldimension.com/ , Shell Directory, Sea Shell Guide of Fulvio Ferraiolo.

www.gastropods.com of Eddie Hardy. It is a big amateur site with beautiful pictures (in 2004 > 23930 taxa, 8634 illustrated, with 18779 images). It includes the picture of my 64 mm record sintype.

https://www.nmr-pics.nl , Rotterdam Natural History Museum.

http://homepage2.nifty.com/bigai (site Micro Shells BISYOGAI, Japan), of Mrs. Machiko Yamada, with exceptional pictures of Marginella pseudosebastiani .

www.eumed.net/malakos (MALAKOS, Andalucia, Spain), of Alfonso Pina, scientific site with complete list of the Marginellidae till now discovered

www.femorale.com.br  (FEMORALE) very good and wide Brazilian site, with a lot of specific photos. (*P*)

http://www.deepnreef.com/ (Deep'n Reef Shells, Portugal), of Paulo Granja, an expert and specialized site in shells of West Africa, with very fine pictures of all species of the Marginella glabella Complex, and not only (*cfr.P*)

www.atollseashells.com (ATOLSEASHELLS, Portugal) of Gonçalo Rosa, another expert and specialized site (*S, G, cfr.I*)

http://www.shellspassion.com/ (SHELLS PASSION, Mougins, France) of Philippe Quiquandon (*G*)

www.topseashells.com of Michel Jourdan, Philippines (*G*)

http://www.conchology.be/ of Guido & Philippe Poppe, Philippines. It contains the section Available Shells & Encyclopedia with a huge lot of pictures of marginellas. (*G, I, "lamarcki cfr."*)

www.jaxshells.org/reverse.htm (USA) in Harry G. Lee's section Reverse Coiled Gastropods, devoted to left-hand shells, contains the photo of intermediate specimens between S and P. Both specimens were called M. sebastiani. In my opinion instead both shells should be M. pseudosebastiani, but on the left the hybridation with S is more evident.

In the shell, with standard dextral worl, on the right of the picture, the features are completely of M. pseudosebastiani.

This specimen comes from Nouakchott, Mauritania, trawled 200-300 m.


You can see features more of S than of P in the shell on the left, with worl contrary to the standard.

I think that it could be a left-hand true hybrid P X S. The outline of the shells and the outside lips are characteristic of P, but the white spots are too big. Large spots are characteristic of S, but, considering the single feature, that is not discriminating. This left-hand specimen comes from Cayas (= Kayar?), Senegal, 80-100 m (meters) depth.


Data from Al Deynzer, Showcase Shells, and Harry Lee communication. It seems that the spots get smaller as the 2 shells move towards North Africa and move in depth, but the latitude and depth are not significative

In both cases, the axial white subsutural flames, which are characteristic of P, are present. This feature is the discriminating factor between P & S.

Also see in my photographic Quick reference guide other usable pictures for the distinction between P & S.


www.alboranshells.com (ALBORAN SHELLS, Malaga, Andalucia, Spain), of Marthe Bellocq and Franco Gubbioli, that in 2001 pubblished very significant photos of 2P +2S, shells with regard to the geographic distribution and the morphologic distinction between P & S. Moreover see forward the chapter Implications of P & S with G, inducing L morphology. (*G*)



Analysis of P versus S.

Left: Gubbioli referred 2 shells coming certainly and exclusively from "Mauritania" (see my Distribution). They are "no-typical" Marginella pseudosebastiani Mattavelli 2001, 40/50 mm length. I think the photo is more coloured than the coloration of “typical” P. The light dots on the back of the "typical" P shells are rarely aligned as in the two 40/50 mm specimens, which tend to cross the morphology of some "lumperias", while always they remain good P.



For the "typical pseudosebastiani”, see the photo below on the left (taken from ALBORAN SHELL too), of a specimen coming from Mauritania, 55mm length.

On its right, another interesting photo of ALBORAN SHELL declared "pseudosebastiani freak", from Mauritania, 42 mm.




Right: 2 shells  coming from  "Guinea" of

"nearly typical" Marginella sebastiani Marche-Marchad & Rosso 1979, 56/54 mm length.

The coloration could be typical of the sebastiani morphology, but there are also less coloured S.





In fact, on the bottom right, a photo of another almost typical ALBORAN SHELL specimen, Marginella sebastiani, 53 mm length, from Guinea.

M. sebastiani also has considerable variability (see Guide), while the primacy of variability belongs to M. glabella.

In the group S, P, G, L the intermediate forms are very numerous, but without assuming that the complex could be a single superspecies/superklepton.




In the previous 3 photos and in all the following ones, I have tried to keep the lengths of the shells in a ratio of scale, comparing one another.


New biological category (L) in the M. glabella Complex.

Implications of P & S with G, inducing the morphology of L.


Above, note the mixed pitting of an "almost typical" M. glabella Linnaeus = G, West Sahara, 34 mm long (photo from the ALBORAN SHELLS website).

Note also the difference between the slopes of the shoulder, under the suture of the last turn: towards the apex the slope is greater than towards the head of the mollusc. The head is at the bottom in the photo.

The opening is elongated towards the head of the shell. The apex has a fairly open cusp angle, about 80 degrees.


The morphological differences are evident comparing G to the almost typical P & S, and it would seem so also for 4 other shells, proposed as G in ALBORAN SHELLS, see photo on the right, West Sahara, from 33 to 39 mm length.

G is such a variable species that it is very difficult to typify (the first 2 could be “almost typical G”; the third, at the left bottom, could be a leucistic form, definable G albida).


In the case of the fourth specimen, at the right bottom, I disagree with the ALBORAN SHELLS site. In the past, many varieties that I thought come together in G, now I believe that they could be separated, because of a real biological difference.


In July 2017 I had called only the fourth morpho in the lower right "pseudoglabella", morpho intended as a separate biological category, but unfortunately confusable with an atypical G, and also especially with P, less with S and with I (and perhaps confusable with V, or better with the true L, in variety E).

Today, due to the differently angled shoulder of the shell, more leaning towards the apex (as in true G), it would be better to define this specimen "pseudoglabella cfr.” (orE cfr.”? Or a true hybrid?), about 36 mm length.

The specimen of "pseudoglabella cfr." appears to me more elongated than the other G and with the edge of the mouth more elongated than that of the other 3 shells considered true G.





     My doubts will be confronted on the page “visayae”, Fig. 2.


Intuition of the existence of "pseudoglabella" = L


The Complex is apparently almost inextricable with regards to the biological belonging of the single morphs, while different morphological typologies can be distinguished, sometimes with difficulty, as for example "pseudoglabella cfr.".

For me "pseudoglabella" means a series of morphs difficult to typify, however belonging to a new and highly variable "species".

The light dots are mostly a little screened, as in the case of the specimen "pseudoglabella cfr." mentioned above, with the dots regularly all separated from each other, but in other specimens, which then I will declare syntypical, the dots are often knead, making the chaotic screening, see next Note regarding the "lamarcki cfr." of the Conchology Inc. Web site, then declared true L.


The average total shell stretches of L (mean stretch = 1.91) can become like that of P (= 1.96) & S (= 1.83), or rather we say that it is on average an intermediate stretch between S & P, with the mouth of L slightly more elongated than that of G, which has a shape with an average total stretch of 1.69.


The shell of L can sometimes be less elongated than S & P, so that it can be mistaken with M. glabella.

There are morphs of L that are often elongated as S and almost always have the shell shape of P, e.g. photo immediately below right, specimen 52.5 mm long, with morphological characteristics to deserve the qualification of E, which will then be understood as a variety of L on the "visayae" page.

Next we will see that the specimens ex "lamarcki cfr." of Conchology, Inc., which for me will be made typical of L, actually have the apical loop slightly more elongated than apical loop of the specimen 52.5 mm long.


The resemblance of L with G in the majority of cases is strong, but the pitting and sometimes the elongation can cross the morphology of P, without appearing exactly P (and not even appearing S, which instead it has much larger and less numerous light dots).


The typology of the L dots, precisely in the "variety" E, also recalls those of Marginella irrorata = I var. pseudoirrorata = T, as in the same photo immediately below right, specimen of 23.5 mm.

I would not exclude for L the possibility of multiple hybridization G, P, S, perhaps hybridogenetic (to say klepton).

There may even be links with the biology of Marginella irrorata pseudoirrorata.


Therefore the doubtful identification of L appears to me contradictory, and in fact sometimes L is indicated in some of the abovementioned links (and in other sources) with the wrong names of S or P or G or even M. irrorata gigas, apart the wrong identification with the "lamarcki cfr:" of the following Note regarding "lamarcki cfr." of the Conchology Inc. Web site.


Here are some photos, in addition to the numerous photos of "varieties" that are candidates to be L. These "varieties" had appeared in the discussion on the Universo lumperia page, starting from picture Fig. 00, in 2014 already supposed to be probable L.



Marginella glabella cfr. 38 mm, with separated dots.                   Marginella pseudoglabella cfr. (var. lellae = E), 52,5 mm.                  M. irrorata (var. pseudoirrorata = T) 23,5 mm.


The "ideally typical pseudoglabella" could be placed in the middle between the left 38 mm and the central one 52.5 mm in shell length, however a typical L will be syntypicized in the ex "lamarcki cfr." of the Conchology Inc. site, therefore the 52.5 mm specimen (= E)  is a morph to be compared with L.

You can think that on the left (38 mm) there is yet another variety of G (which is probably exact, but note that I wrote G cfr.) and on its right there is a variety of P, or one of S with small and numerous dots, or still a large giant G. All these 3 identifications appear wrong to me, regarding the 52.5 mm specimen, which would instead deserve a specific separation as new “variety of species” = E, to be compared with a typical new “species” = L.

In the case of the large 52.5 mm shell, the subsutural flammules are not typical of P, the dots are too small and numerous to be of an S and its total elongation (1.78) is not from G, while the mouth elongation (1.28) falls oddly into the mouth elongations of the G.


The clear subsutural flammulas of a syntipic L (see forward ex "lamarcki cfr." of the Conchology Inc. site) are relatively scarce in number compared to those of P, but in the specimen called E (52.5 mm) some flammulas widen in speckles, as sometimes it happens in some rare cases of S, where however flammulas are usually almost always absent.

Note that the flammulas of this E are more enlarged than those of the "pseudoglabella cfr" 36 mm long, the fourth morph of the previous photo.

Incidentally, I know that the whitish flammules of a typical P are lean and slender, fairly dense in number, always present under the suture, in fact the subsutural flammules are a discriminating factor for the identification of the species P.

Indeed, the flammulas of L sometimes resemble those of G, where they are always present, but I would not say that they are always the same as those of G.

The presence of flammules is common to P, G & L, therefore alone it is not a clear element of distinction, except mostly for the distinction from the typical S, which however also presents a considerable variability.


Hybrids P X G X S?


       45 mm, Mauritania, perhaps PXS                                            47,8 mm, Mauritania, perhaps GXS                                          37,3 mm, Senegal, perhaps PXG #


# I remember that in 2005 I had called "antinea" some then believed varieties of G, but in 2011 I hypothesized that the "antinea" could actually be klepton PXG. The light dots of the livery of the 37.3 mm shell are more distinct than those of other "antinea", to the point that the 37.3 mm shell could be a "not antinea", neither variety 2005, nor klepton 2011, but be a variety of the new category L, better to say "L cfr.", or it could be an occasional hybrid.


The morphologies to be compared with L could form a new multiformed biological category, very dispersed in single varieties, or it could be a bunch of very atypical varieties each of the other species, if not a bunch of more or less hybridogenetic hybrids, even in multiple hybridation.


Could the 3 images above be of 3 different hybrids? or all of variable forms of the same "species" L?

Of course, the specimens are not typical forms of P, S or typical G. But they are neither certain forms of L.

All the 3 above specimens could be forms of a multiklepton P X G X S, with the parent species still to be identified by exclusively genetic analysis, as their morphology is confusing.


"pseudoglabella = L" with percentage numerical ratios.


The specimens that I know of the species/klepton L are not very homogeneous one another.

In other Web sites you can find photos of splendid dark forms declared varieties of G and forms declared varieties of S with numerous small dots, at the extreme limits of the variable morphologies of L.

I would instead consider these as extreme varieties belonging to L.

In particular for the dark forms of G it is necessary to distinguish:

• if they are precisely forms of the species G, as so far almost universally declared by the majority of the Web sites, or rather if they are forms of the new species L, which would thus enclose a specific slice of the morphology universally attributed entirely to G.

• if, on the other hand, they are precisely forms of L, since there are many intermediate varieties between L in relation to S and G, it is necessary to evaluate the presence of any possible klepton L X S and L X G.

In fact, if L is a species, it could hybridize with neighboring species, not excluding LX P too. In my photos above, the 52.5 mm long specimen may be a hybrid LX P? Morphologically we will never know for sure, however I suppose that it may be an unhybridized variety of L, for the existence of similar specimens.

Actually my assumptions are simply based on the sight of only about a dozen presumed L in my possession, plus about twenty specimens valued L, in photos from different sources (Web Dealers) and therefore presumably from different geographic origins.


Till now I did not consider a further thirty ex "lamarcki cfr." shells, proposed by Conchology, Inc. Web site, for which see the following Note regarding them.

There is absolutely no connection between the real species Marginella lamarcki Boyer, 2004 and L.

Do not call "lamarcki cfr." those morphs that seem to be "L cfr. = pseudoglabella cfr.". Any reference of L to "lamarcki" Boyer is misleading. However I will have to use the name of lamarcki cfr.”, to correct it, when referred to L.


Similar considerations can be made in the estimable cases L X I, in particular E X T, including the 23.5 mm long specimen T photographed above, morphologically considered as a syntype, together with the 21.5 mm specimen, of the "pseudoirrorata" variety of the species M. irrorata.


Let's consider the number of specimens, which can be merged into a single group, in order to classify it with respect to the total number of all specimens of other similar groups of the whole Complex, that is with respect to all those specimens recognized as belonging to different species of the same Complex. The aim is to obtain frequency percentages of the single species, as already considered in the article "Other kleptons in the Marginella glabella Complex?".

In this article 2017, thinking of L = (G X S), indeed mixed with (G X P) "not antinea", adding the dark forms ex G, considered L and having also included the ex "lamarcki cfr.", which can be linked by colouring to the dark forms, I wrote (in magenta at the bottom of that page) a presence of L in about 8% of the total Complex. In 2020, I believe that 8% could be an estimate that is a little overwhelming, but still plausible.


A much lower percentage (<2 %?) in general would push towards the hypothesis of possible sterile hybridizations, or alternatively, and in particular in the "specific" case of L, to the hypothesis of a new very rare category. I discard as a further alternative the belonging of the various dissimilar specimens of L each to already known species of the Complex, in different atypical varieties.


These are all inferences to be verified through a greater number of specimens, and better with genetic analyzes, which, however, could even lead to a general biological unification of the whole Complex, which is highly questionable.

From a purely collecting point of view, L remained a very rare "species" for me, until I discovered the former "lamarcki cfr." of Conchology Inc. Web site. Their existence lowers the level of rarity, but L is still a fairly rare "species".


Note regarding "lamarcki cfr." of the Conchology Inc. Web site.


The same site subsequently recognized the new "pseudoglabella" species and so has now changed the names of the "lamarcki cfr.", which however are still referred to below as such, being the original text written in 2017 (and in 2020 left substantially almost unchanged).


The site Conchology, Inc. called "Marginella lamarcki cf." some shells from Senegal (about thirty, as the photo beside) which seemed to me to be very long L, since the real rare M. lamarcki Boyer, 2004 is considerably smaller and it is not relevant to L.
The case is stunning for several reasons:

1) the lamarcky cfr.” of Conchology Inc. are almost like my L, as introduced in 2014/2017.

2) in the case of elongated forms of L, the presence of L in Senegal is confirmed in a considerable number of specimens. The number of specimens of suppositories L known to me previously was about twenty, therefore the total would rise to about 50, a significant number, which would make the hypothesis of possible sterile hybrids discarded. The new "species" L remains however quite rare, compared to the frequency of the species G, I, P, S.

3) if these are not L forms, they are almost thirty specimens very different from the comparable species already known of the Complex, to suspect the presence of a new biological category (klepton or species), excluding the hypothesis of occasional hybrids and excluding that the specimens in question are hypothetical atypical varieties of already known species.

4) the length of the shells from Conchology, Inc. varies from about 46 mm, up to 68.8 mm of the photographed specimen beside. On average they are between 51/60 mm long, a considerable length for the Complex, to be positioned among the largest species.

5) unlike my specimens previously considered L, the light dots in their livery are sometimes mixed, and the elongation of the profile of the Conchology Inc. shells is also more acute than that of my specimens.


In summary, it is probable that these are very elongated varieties of L.

I have assumed the thirty homogeneous specimens of the photos of Conchology, Inc. as syntypes of L, intended as a new species L. Some "pseudoglabella" I proposed in my previous photos could actually be hybrids between this new M. pseudoglabella and some other nearby species (P, G, S, I), or simply atypical varieties of M. pseudoglabella new “species”.

For details, please refer to the article  Nuovo sguardo ai mondi di Marginella glabella e pseudoglabella, 2017 or Descrizione comparativa di Marginella (Kl.?) pseudoglabella Mattavelli, 2018 nuova "specie" (articles only in Italian).


Having transferred the same name L = Marginella (kl.?) pseudoglabella Mattavelli 2014 to all thirty specimens photographed by Conchology Inc., in 2017 I invalidated the year of my 2014 declaration, made on the Universo lumperia page.

In addition, as the paper description was made in April 2018, MMM magazine n° 99, the year 2017 is invalidated too.


The new "species" could be roughly divided into 2 subspecies or subkleptons, of which the specimens of Conchology, Inc. would represent the subspecies or a subklepton typical of Senegal, and some of my specimens of L (some of which may perhaps be hybrids) could represent an atypical subspecies or an atypical subklepton of Mauritania.


However, there is Marginella (kl.?) pseudoglabella new biological category, distributed from Mauritania to Senegal, with greater frequency and liveliness in Senegal. I do not exclude that the geographical range could be wider, perhaps with further local subspecies or subkleptons in other geographical areas of West Africa, even if not adjacent to Senegal and / or Mauritania.


For the new category L I think that the hypothesis klepton is more probable, rather than the hypothesis species, given the reinvigoration of the large specimens of Conchology, Inc. and the rather low percentage of presence of L, in relation to the percentages of the other true species of the Complex.


Deepening on the homogeneity of the characteristics of L.

My Ls, apart from the ex "lamarcki cfr." above, are not all homogeneous as the P or S or G or "typical" I, which appear well grouped individually and precisely they form homogeneous groups of similar individuals. These can be subdivided into subgroups (atypical varieties ) of individuals also similar to each other, but slightly less similar to the nucleus of the "typical" subgroup, however varieties comparable in similarity to a well homogeneous "typical" nucleus.

Within the group of my L there is no clear homogeneity of nucleus and all individuals appear each with its own individuality, scarcely similar to the other individualities of the group, except for some ideally typical morphological characteristics, which could agglomerate all individuals in L. However these characteristics can scarcely be found all exactly and simultaneously in the same individual.

Instead the thirty specimens of ex "lamarcki cfr." of Conchology, Inc. are largely all homogeneous: this is the reason making me choose a possible L holotype among those specimens. Among my L, the specimen most similar to those of Conchology, Inc. is the one photographed above 52.5 mm, coming from Senegal, Gorée bay, depth about 10 m. I propose that as a future lectotype, if a holotype is not designated among those syntypes. In fact, I believe that the majority of the Conchology, Inc. syntypes (= L) were only photographed on their website (Shell Encyclopedia), but they are no longer materially available, since they are scattered among various collectors.


I recall below the ideal characteristics of my first idea of ​​L, found partly in this lectotype:

·         small and variable dots from retiform to chaotic, always separated one another (what is questionable for the syntypes of the group ex "lamarcki cfr."); dots sometimes larger (e.g. LXS cases),

·         total elongation (mean stretch = 1.91) variable from the typical stretch of S to that of P; average mouth stretch variable slightly beyond the typical elongation of G (but below average in the lectotype, where the mouth stretch is like in the majority of G),

·         subsutural flammulas from those typical of G to those of P, generally scarcer in number (but the whitish flammules can sometimes be better distinguished, since they can appear in spare, short and wide spots, as in some gerontic S, although the flammules of L are usually thin and slightly slender, precisely between G & P),

·         usually brick background color such as S, average dimensions between those of giant G and those of the largest P, denticulation of the margin variable from poor (as in the lectotype) sometimes medium (like that of some adult G).

Some ideal characteristics of L must be corrected by the knowledge of the aforementioned specimens of the ex "lamarcki cfr.", syntipic of L: very large dimensions in Senegal (even larger than the average dimensions of P), light dots sometimes mixed, that is, not always separated one another; average mouth stretch of L almost always about 1.36, compared to about 1.31 average mouth stretch of G.


The dots, sometimes mixed, are the most dubious morphological characteristic, perhaps useful for a sub specific distinction between the specimens of Senegal (where the GXS hybridogenesis could prevail, with dots sometimes mixed towards G and sometimes distinct towards S), and the specimens of the Mauritania (where it could be GXP, with dots sometimes mixed towards G and sometimes distinct towards P). On the border between Mauritania and Senegal, there could be an SXP hybridogenesis or there could be real sterile hybrids (with dots sometimes separated or sometimes kneaded, according to the hybridizing couple). I consider the kneading as a prevalent characteristic of a hypothetical tendency to G, if L is understood as klepton, or the kneading as a variable characteristic of L, if instead L is understood as an authentic biological species.


Despite the inhomogeneity of some individuals of L, in my opinion, they, individually considered, cannot be morphologically assigned to any of the nearby already known species of the Complex (P, S, G, I): that makes me opt for the probable existence of L as a new multiform biological category, due to the relatively high number of found specimens (apart from the hypothesis of possible sterile occasional hybridizations for very rare specimens).


L is a bit like the Comacchio bridge, with branches in several directions: in the case of L there are the directions P, S, G, I with attraction and at the same time repulsion to and from the adjacent nuclei of the species.

You can also think of directions not lying in the same plane, in a spatial view of the whole: L can be placed in the center of an imaginary tetrahedron.

It is as if the virtual nucleus of L was quartered according to the 4 morphological directions mentioned. I do not know if that happens in the pulverization phase of a large original compact nucleus or in the aggregation phase towards a new biological category; I don't want to discuss biological evolutionism.

Perhaps L is widely dispersed geographically from West Sahara to southern Guinea. I could be more precise about biology if I knew a greater number of specimens and all the places of origin of the various L, but unfortunately L is quite rare on the collector's market. This does not mean that L subforms are rare in nature, somewhere in West Africa. Indeed I believe that somewhere they are temporarily almost common (eg Senegal for the ex "lamarcky cfr." of Conchology Inc.).

Flavio Mattavelli      


Links page release, limited to links references only to Marginella pseudosebastiani, preceding the 2006.

Integration with news on "pseudoglabella" and announcement of Marginella (kl.?) pseudoglabella new species, update September 2017 (mixed page English / Italian).

Remake of this page, July 2020:

Page top only in English language.

Same page only in Italian language.


Home page of the 4 Sections (41 pages in 2020) and the Shells Section start page.

Shell Section is composed of total 16 pages, here’s the remaining 14 pages:


Article “La variabilità fatta specie” in 3 pages (only in Italian language):

starting page , for the distinction between M. glabella & M. irrorata, photographic wide guide, 2005. 

second page Marginella glabella Marginella irrorata morphologic hybrids, M. g. mutabilis Mattavelli 2005 new hybridation subspecies and its variety M. g. mutabilis elongata as subvarieties of the species M. glabella, if not all varieties of a single klepton: "mutabilis" . To be revised.

Enclosure (3° page) concernig Marginella glabella antinea & problematicaanalyzed as new varieties in 2005, morphologic hybrids between M. glabella M. pseudosebastianibut which could be varieties of an "antinea" klepton instead. To be revised.

Marginella pseudosebastiani Mattavelli, 2001. Statements on the M. glabella Complex (2006 article, English only)

Marginella pseudodesjardini Le Béon, 2012, today studied as a true species, but which could be a remarkable klepton instead, ex et alias variety of "(klepton?) incredibilis Mattavelli, 2011. Notes on the different "pseudodesjardini giselica" Mattavelli, 2013 form. (Italian only)

Update 2014, November, article Universo lumperia, ambiguous forms not yet classified, morphologic hybrids SXP and SXG = possibility of the new Marginella kl.? pseudoglabella Mattavelli 2014 (Italian only)

Specie/klepton Concepts. 2015 February Update (Italian only)

"Other kleptons in the Marginella glabella Complex?" With photografic table of the hybrids & basic species. 2017 Update (Italian only)

"pseudoglabella supposed new species", 2017 (Italian only)

"pseudoglabella settled new species", 2018 (Italian only)

"pseudoirrorata new variety", 2017 (Italian only)

Italian Atlante ex Guida di identificazione fotografica regarding all current species of the Marginella glabella Complex & their morphologic hybrids, with shell spots resumptive drawing & notes (Italian only)

Atlas ex Quick reference English guide. Pictures of Marginella sebastiani, desjardini, pseudosebastiani, pseudodesjardini, goodalli, glabella, irrorata, pseudoglabella & some morphologic hybrids

Marginella (Kl.?) visayae Mattavelli, 2018, supposed new “species” or klepton G X I (Italian only)


Other Sections pages, accessible from the home pages of the single other 3 Sections:

Model Aircraft Section (16 pages only in Italian: aeromodellismo).

Machinery Section (7 pages, some in English) with references to the machines built by the Cavalleri Mattavelli Sas company.

Gorgonzola Section (2 pages, only in Italian). Long monograph on "My Gorgonzola after 1990", miscellany with origins of the city and the homonymous cheese, supplemented by some chatter from a conchologist.