Papillifera papillaris, a common, but little known species

Hartmut Nordsieck (VI.2011, updated V.2021)

I. Introduction

The genus Papillifera Hartmann 1842 includes two species, P. papillaris (O. F. Müller 1774) and P. solida (Draparnaud 1805). Both originate from Italy; P. papillaris is widely distributed in the Mediterranean, P. solida has been found beyond Italy only in southern France (Provence). Both species differ mainly by the dark subsutural band of the shell, which is present in P. papillaris and in general absent in P. solida.
Though P. papillaris is known as a species since a long time, the knowledge of its intraspecific forms is poor. The wide distribution untypical for a clausiliid with its striking restriction to human settlements has not been explained so far. While 19^th century malacologists had achieved at least a basic knowledge of the forms of this species (see part II), modern malacologists, except for an unnecessary dispute on the correct species name, supplied almost no further information on its diversity and its distribution (see part III).
The results of the author’s own research of P. papillaris in Italy and other Mediterranean countries are summarized in parts IV and V.
In all probability, the name Turbo bidens Linné 1758 is a senior synonym of Helix papillaris O. F. Müller 1774 (see Nordsieck 2013a). Though the morphological statements, on which Kadolsky’s neotype designation for T. bidens (a specimen of Cochlodina incisa Küster 1876) is based, are incorrect and the designation thus arguably invalid (for arguments see 2013a), the International Commission on Zoological Nomenclature (2015) thought it appropriate to decline the setting aside of that neotype. Therefore, the species must be named P. papillaris.

II. History

P. papillaris has been diagnosed and figured by Rossmässler (1836: 12, pl. 12, figs. 169-170) under the name Clausilia papillaris. Additionally to the type form he described a variety C. p. var. virgata „Jan“ from „Oberitalien“ (: 12, fig. 170) with the following diagnosis: „testa costulato-striata, peristomate continuo; palato calloso; cervice basi in cristam compressa“. This diagnosis, with the exception of „palato calloso“, corresponds with the definition of P. p. affinis (= virgata), which resulted from my own research (see part IV).
Philippi (1836: 139, pl. 23, fig. 30) separated Clausilia affinis from C. papillaris with the diagnosis „sutura concolore et striis elevatis sublamellaribus“. Later on, the same author (1844: 116) united C. affinis and C. p. var. virgata to his C. papillaris var. β, for which he repeated Rossmässler’s diagnosis of C. p. var. virgata. C. affinis has priority over C. p. var. virgata, because it was published in 1836 somewhat earlier, like other names of Philippi competing with those of Rossmässler.
Pfeiffer (1848: 453-454) listed the species as C. bidens, with var. β with C. affinis and C. p. var. virgata treated as synonyms. His diagnosis corresponds with that of Rossmässler for C. p. var. virgata, without paying attention to the difference of the cervical keel.
Küster (1850: 52-54, pl. 5, figs. 28-37) also used the name C. bidens, with var. A instead of var. β. In his diagnosis: „Costulata, palato calloso; peristomate continuo, soluto“ the difference of the keel is not mentioned, too.
Schmidt (1868: 107-108) treated C. papillaris and C. virgata with reservation as independent species, because he had received mixed samples of both (indication of a possible syntopy). He distinguished the latter by „den breiter umgeschlagenen oben durchweg lostretenden Mundsaum, die flachen Umgänge, die stärkere Streifung“. But he also mentioned „Mittelformen“, for example that from Toulon in France.
Paulucci (1878: 13-14) listed for the species named C. bidens the varieties var. circinata, var. virgata = affinis and var. brevissima. The var. circinata was characterized as follows (: 39): „très légèrement strié, … largement pourvue du bourrelet“; so she assumed for this variety an intermediate position between the type form and the var. virgata. C. b. var. brevissima L. Pfeiffer is a small form from S. E. Sicily distributed under this name by Benoit. Further, she (: 39) described two ribbed species of the group from Calabria, C. transitans and C. deburghiae. With the latter, which is a form of P. solida, she wrongly united, in accordance with O. Boettger (: 14), the ribbed variety of P. papillaris, C. tinei Westerlund, from Sicily (see Nordsieck 2013b).
Boettger (1878: 51) subdivided the species, which he, too, named C. bidens, into three subspecies: subsp. bidens (among others with var. circinata), subsp. virgata (among others with var. affinis and the ribbed vars. transitans and deburghiae + tinei, in accordance with Paulucci) and subsp. brevissima. Furthermore, he gave accurate information on the range of the species. A widely ribbed form from Sicily was described by him as an independent species, C. rudicosta.
Westerlund (1901: 137-138) treated Boettger’s subspecies, as well as the ribbed forms of P. papillaris, as species and gave a list of all their varieties described so far.

III. Modern work

By their work 19^th  century malacologists provided a foundation for the subdivision of P. papillaris, on which modern researchers could have based their work. But this did not happen. In the following papers of 20^th century no attempt was made to work out a subdivision of  P. papillaris, which reflects its actual diversity.
Forcart (1965: 122-123), after examination of the samples of P. papillaris available for him from southern Italy, stated: P. papillaris „ist ausserordentlich variabel. Zahlreiche Populationen weisen Schaleneigenheiten auf und wurden mit besonderen Namen belegt. Vermutlich beziehen sich die von Westerlund (1901: 137-138) unter den Namen … angeführten Formen auf Populationen oder auch individuelle Varianten von P. papillaris„.
Alzona (1971: 94-95) listed all varieties which, as far as he knew, had been described from Italy, as subspecies of P. bidens and P. affinis without review. In a footnote one of the editors of his paper (: 94, as I assume, Toffoletto) stated: P. affinis „non è probabilmente altro che un insieme di popolazioni, con nicchio robusto, ispessito, e costulatura talora molto evidente, del ciclo variabilissimo di P. bidens, …“
Giusti (1973: 240-246) regarded all taxa described so far as synonyms of P. papillaris, which he did not divide into subspecies with the following explanation (: 245): „ho potuto constatare come alcune „specie“ altro non fossero che forme di passaggio tra una forma e l’altra o tra una forma e le semplice P. papillaris (Müller)“. „Ho potuto … constatare … la variabilità delle popolazioni ed il loro mutare in rapporto alla esposizione, alla freschezza o aridità del biotopo“. And concerning the forms from Sicily and Calabria the following (: 246): „Si tratta indiscutibilmente di demi locali, casualmente distribuiti ed inframezzati da altri demi a loro volta più o meno differenziati, certamente in rapporto solo con determinati fattori ambientali“.  Neither the intermediate forms were specified, nor the assertion that the differing forms from Sicily and Calabria were simple modifications has been founded. On the other hand, Giusti (: 237, fig. 28 A, C ) was the first, who gave an accurate figure of the genital organs of the species (from Isola Salina).
Manganelli et al. (1995: 25) in the Checklist delle specie della fauna italiana listed P. papillaris without subspecies, with the addition (= affinis = circinata = transitans = virgata).
Giusti et al. (1995: 375-379, figs. 421-427) determined the species from the Maltese Islands as P. papillaris without assigning it to a subspecies and stated (: 379), that „the Maltese populations correspond to the typical morph“ (this is only based on the sculpture, see part IV). They repeated that C. p. var. virgata and C. affinis should be regarded as „local demes“. And: „However, some authors still refer to them as true subspecies, ignoring evidence to the contrary in the literature“. This „evidence“, however, cannot be found in the literature.
The statements of Giusti and co-workers on the intraspecific diversity of P. papillaris were not confirmed by my research (see part IV).

Figs. 1-2. Papillifera papillaris subspecies.
Frontal und body whorl dorsal. Scale 10 mm.
Fig. 1. P. p. papillaris, mainland Italy (different localities), ex N.
Fig. 2. P. p. affinis, Sicily (different localities), ex N.

IV. Subspecies division

Until now my research of the intraspecific diversity of P. papillaris was restricted to shell characters. The material examined is deposited in the collection of the Forschungsinstitut Senckenberg (SMF) and in my own collection (deposited mainly in the Staatliches Museum für Naturkunde Stuttgart). It comes from 182 localities altogether, most samples from Italy, which is assumed to be the centre of origin of the species. The sample numbers from the different regions are the following: Mainland Italy 72, Sicily 39, Malta 4, Tunisia 7, western Mediterranean countries (Sardinia, Corsica, Balearic Islands, S. France, Catalonia) 22, eastern Mediterranean countries (Dinaric countries, Greece, Turkey) 38. 52 samples of P. papillaris from mainland Italy, Sicily and Malta were subjected to a more thorough analysis (if available, of 10 specimens per sample).
The G-type closing apparatus = CA of the species (Nordsieck 2007: 91-93; see Figs. 3-4) is nearly invariable. Therefore only the following characters could be used:
1. White surface layer;
2. sculpture;
3. cervix of body whorl with basal keel;
4. peristome;
5. parallel lamella and spiralis rudiment (with this term not the lamella fulcrans is meant, but the rudiment of the spiral lamella running from the fulcrans outwards);
6. inferior lamella;
7. subcolumellar lamella;
8. palatal callus and anterior palatal plicae (proceeding from the palatal callus inwards).
It resulted that only the characters 2., 3., 4., 7. and 8. were suited for the definition of intraspecific taxa.
The most important character is the development of the peristome. By this character, two large subunits are defined: major subspecies P. p. papillaris from mainland Italy south to N. Calabria and major subspecies P. p. affinis from Sicily, S. Calabria, Malta and Tunisia (Nordsieck 2013b: 8; Figs. 1-2). In P. p. papillaris, the peristome is always or mostly attached, in P. p. affinis it is detached. These two major subspecies can also be identified in the material from the remaining Mediterranean countries which makes possible the reconstruction of the distribution of the species from Italy into these regions (see map Fig. 5).
As a result of this distribution, intermediate forms have originated by secondary contact. An intermediate form, which has already been recognized by A. Schmidt (1868: 107), occurs in Toulon, S. France. I could find a further one, as far as known, restricted to the Penisola Sorrentina and the island of Capri, Campania; it is, simply said, a P. p. papillaris with the detached peristome of P. p. affinis. Also the form from Malta (Fig. 4) is intermediate between P. p. affinis and P. p. papillaris, because its peristome is attached or detached.
Further differences between the major subspecies are the following: P. p. affinis differs from the nominate subspecies by a more strongly developed basal keel (see Fig. 2) and a more frequently emerging subcolumellar lamella (in P. p. papillaris not visible in front view in about 1/4 of the examined specimens, in P. p. affinis only in about 1/20). A further differential character, which was unknown until now, is the presence of a complete rudiment of principal plica. In a part of the specimens of P. p. papillaris an anterior upper palatal plica, proceeding inwards from the palatal callus, is continued by a weak, but well-visible fold, which reaches the principalis rudiment above the lunella (see Fig. 3); it is thus recognized as the rudimentary principal plica. In P. p. affinis, such a principal plica could not be observed.
As to the sculpture, most samples of P. p. affinis are more strongly rib-striated (rib number on 2 mm of the penultimate whorl = R₂ means 10-14.5) than those of P. p. papillaris (R₂ means 13-19).
However, there are exceptions, e. g., the form of P. p. affinis from Siracusa, S. E. Sicily, with a sculpture corresponding to that of P. p. papillaris (R₂ mean 17). This form was described by Paulucci (1878: 39) as var. circinata, but in this variety she included also P. p. papillaris from southern mainland Italy. Herewith it is restricted to the form from Siracusa (syntypes SMF 137478).
From this region also Clausilia brevissima L. Pfeiffer 1859 (coming from Benoit) has been described. The examination of originals (SMF) showed that it is more strongly sculptured than var. circinata (R₂ 12.2). A similar form from Lentini is transitional to the latter (R₂ 14.5). After a recent revision both are now separated as subspecies from S. E. Sicily.
The form from Malta (Fig. 4) is weakly sculptured like var. circinata, but its peristome is attached or detached (see above).
P. p. affinis from S. Calabria has different sculptures (Nordsieck 2013b: range of P. papillaris in Calabria fig. 8). The form from lower altitudes near Stilo is weakly sculptured (R₂ 16.5), that from Monte Consolino and Monte Stella more strongly (R₂ 9.5-15). The latter has been described as P. p. transitans (Paulucci 1878). The affiliation of P. p. transitans with P. solida, which I proposed in a former paper (Nordsieck 2002: 36), was wrong.
In S. Sicily more strongly sculptured (ribbed) forms of P. p. affinis have been found (R₂ means 7.5-8.5). Though they occur in close vicinity of normally sculptured P. p. affinis (e.g., near Sciacca, Ribera, Palazzo Adriano, Agrigento, Modica) and have possibly originated more than once, they are provisionally united in a subspecies, which has to bear the oldest name P. p. tinei (Westerlund 1878) (type locality Palazzo Adriano).
A more coarsely ribbed subspecies, P. p. rudicosta (O. Boettger 1878), was described from Muglia near Centuripe, S. E. Sicily (types R₂ 5.6).
The question arises whether P. p. affinis occurring in N. Tunisia is autochthonous or the product of a more recent spread from Sicily (see map Fig. 5). From Ustica also a ribbed form (P. p. punica Bourguignat 1868, R₂ ~ 9) is recorded. This is unique for P. papillaris outside of Italy and speaks for an occurrence in Tunisia since a longer time.
P. p. papillaris occurs in mainland Italy, but the question remains where it is really autochthonous. Giusti & Mazzini (1971: 296) stated that P. papillaris „e‘ specie frequentissima lungo le coste e nell’interno (alle basse quote) di tutta la penisola italiana e nelle isole.“ From this statement one could think that P. p. papillaris has a natural distribution all over the Italian Peninsula. But this is not the case. Nearly all samples of the species which I have collected on the Italian Peninsula came from human settlements, while in the natural environs the species was absent. Thus I infer that in the greater part of the peninsula the species was introduced by man. Only in several localities in Apulia east of Ofanto river and some in Basilicata (surroundings of Balvano) I have collected P. p. papillaris in natural habitats (in my judgement not much affected by human activities). Further investigations are necessary to find out, if these regions are the centre of origin of P. p. papillaris.

Fig. 3. P. p. papillaris, mainland Italy, ex N.
Shell height 12.7 mm.
left: body whorl dorsal, view on lunellar;
right: body whorl frontal, view into aperture, rudimentary principal plica visible.

Fig. 4. P. p. affinis, Malta, ex N.
Shell height 15.5 mm.
Body whorl opened, to show inner lamellae endings and clausilium plate.

Abbreviations: aup = anterior upper palatal plica, cp = clausilium plate, ful = lamella fulcrans, il = inferior lamella, lu = lunella; pal = parallel lamella, plpp = posterior lower palatal plica; pr = principal plica or principalis rudiment; sc = subcolumellar lamella, sut = sutural plica(e).

The result of the research is summarized by the following systematical list:
P. papillaris (O. F. Müller 1774)
Major subspecies P. p. papillaris:
p. papillaris (Fig. 1).
Major subspecies P. p. affinis:
p. affinis (Philippi 1836) (= virgata Rossmässler 1836, = mamertina Benoit 1840, = tabarkana Pallary 1927 (Fig. 2);
p. brevissima (L. Pfeiffer 1859) (= p. circinata Paulucci 1878);
ribbed subspecies:
p. transitans (Paulucci 1878);
p. tinei (Westerlund 1878) (= lanceolata Benoit 1882, = agrigentina Westerlund 1890);
p. rudicosta (Boettger 1878);
p. punica (Bourguignat 1868).
An iconography of Papillifera has been published by Margelli (2014). The subdivision of P. papillaris proposed in this chapter is supported by the numerous figures of the species given in that paper.

V. Distribution in other Mediterranean countries

The work on the material of P. papillaris, which was available from the Mediterranean countries out of  Italy (except of Malta and Tunisia) (see part IV), was restricted to the determination of the major subspecies.
The result of this determination is the following:
Sardinia: P. p. affinis (= sulcitana Charpentier 1852);
Corsica: P. p. papillaris;
France (Provence, Languedoc): P. p. papillaris, in Toulon P. p. affinis x p. papillaris;
Balearic Islands: P. p. affinis;
Catalonia: in and near Barcelona P. p. affinis (= catalonica Fagot 1884 = barcinensis Westerlund 1893), in Tarragona P. p. papillaris;
Dinaric coastal regions and islands from Istria to S. Albania: P. p. papillaris;
Ionian Islands and coast of W. Greece as far as Gulf of Patras and Messinia: P. p. papillaris;
Greece (Korinthos, Islands of Rodos and Naxos): P. p. affinis, in Korinthos P. p. affinis x p. papillaris;
Turkey (Istanbul, Bursa): P. p. papillaris.
From this distribution I conclude that both major subspecies spread from their centres of origin over the regions of western and eastern Mediterranean (see map Fig. 5). Because in all these regions P. papillaris is restricted to anthropogenic habitats near to the coast, it is assumed that it has been distributed by man and his shipping traffic. In some coastal regions, where P. papillaris does not occur or is rare, it is replaced by related species, which possibly have also been distributed by man, P. solida in S. France and Siciliaria (Gibbularia) gibbula (Rossmässler 1836) in northern Adriatic regions.

Fig. 5. Map: Spreading of the two major subspecies of P. papillaris over the Mediterranean, reconstructed from the occurrences of both subspecies outside of Italy (see text).

References

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