INTRODUCTION
The identity of Pagodina bourguignati Coutagne, 1881 has remained unresolved since its original description from the Vallon de Rognac in the Bouches-du-Rhône, south-eastern France. After its publication, the name was initially accepted as a distinct taxon and was repeated in the French literature by Locard (1882, 1894, 1896) and later by Margier (1910). However, its status soon became unstable. Westerlund (1887) treated P. bourguignati as merely a juvenile of Pagodulina pagodula, thereby denying it specific validity. This interpretation was subsequently followed by Germain (1913), who explicitly placed the taxon in synonymy with P. pagodula. The question nevertheless remained open, because later authors did not accept this interpretation. Tryon & Pilsbry (1926) expressly rejected Westerlund’s (1887) view and stated that the shell could not be a young P. pagodula, suggesting instead that it might represent a vertiginid species. Germain (1930) likewise reconsidered the taxon: although he retained it only with doubt, he stated that it had never been rediscovered, that it was certainly not a juvenile P. pagodula, and that it probably did not belong to Pagodulina, perhaps corresponding instead to an undetermined form of Vertigo. Pilsbry (1934) further suggested that “Pagodina” bourguignati might in fact be related to Truncatellina, and Klemm (1939), after direct examination of a specimen, stated unambiguously that it had nothing to do with Pagodulina and should be removed from that genus as a Truncatellina. Despite these successive reinterpretations, no stable conclusion followed, and the name was never restored to practical use as a valid species. In later French checklists, the taxon was no longer maintained as distinct but was instead absorbed into the synonymy of Pagodulina austeniana by Pavon & Bertrand (2005) and in TAXREF (Gargominy 2022), whereas MolluscaBase (2026) still retained it under an unresolved status (“uncertain > unassessed”). In this sense, the taxon was not simply overlooked; rather, it remained historically unsettled, repeatedly cited, reinterpreted, or synonymised, but never critically reassessed based on the original specimen and associated archival evidence.
The taxonomic problem became more explicit after Truncatellina beckmanni Quintana Cardona, 2010, originally described from Menorca, was reported from the Bouches-du-Rhône as new to the French fauna by Dommergues & Gargominy (2024). This recent French record concerns the same regional context as Coutagne’s (1881) forgotten species and raises the question of whether P. bourguignati and T. beckmanni represent distinct taxa or the same species under different names. The comparison of the shell illustrated by Quintana Cardona (2010), the extant specimen preserved in the Coutagne collection, and the newly collected topotypic material from Rognac provides a direct way to test this hypothesis.
More broadly, taxonomic work on Truncatellina remains largely fragmented and regional. Important contributions have addressed particular insular or regional faunas, for example in Macaronesia (Hutterer & Groh 1991), Croatia (Štamol 1995), Greece (Triantis et al. 2004), the Iberian Peninsula and north-west Africa (Holyoak et al. 2012), and more recently through critical morphometric reassessments of problematic taxa (Kneubühler et al. 2020) or local molecular re-evaluations (Cucherat & Guiller 2021). In that context, the clarification of overlooked historical names remains necessary for nomenclatural stability and for accurate faunistic interpretation.
Accordingly, this paper re-examines the original material and archival evidence relating to Pagodina bourguignati Coutagne, 1881, documents newly collected topotypic material from its type locality, provides a morphometric comparison with T. beckmanni Quintana Cardona, 2010 and T. callicratis (Scacchi, 1833), determines the status of the type specimen, and evaluates whether P. bourguignati and T. beckmanni refer to the same species.
MATERIAL AND METHODS
The original material preserved in the Coutagne collection at the Musée des Confluences (Lyon) was examined from photographs and documentation supplied by the collection. The relevant specimen is catalogued as MDC.45030705 (Coutagne no. 834), labelled “Rognac, alluvions”, and attributable to Coutagne’s original gathering.
Archival documents associated with G. Coutagne’s collection were consulted, especially the collection notebooks 6J001 and 6J002, the letter dated 18 January 1881 to Bourguignat (6J053), and Coutagne’s manuscript drawing (6J016). These documents were used to assess whether Coutagne had one or several shells available, to verify the correspondence between the extant specimen and the published description, and to compare the archival dimensions with those given in the original description.
On 9 February 2026, an opportunistic field survey was conducted to confirm the presence of the species described by Coutagne (1881) as Pagodina bourguignati and litter was collected in the Vabre de Malaga, referring to the locality described by Coutagne as Vallon de Rognac, municipality of Rognac, near the Étang de Berre (Bouches-du-Rhône, Provence, south-eastern France). The sample was processed using a Winkler extractor in the field. Approximately 1 L of litter was collected from sheltered litter accumulations beneath vegetation. It was then dried at 37 °C for 24 h, sieved through a column of mesh sizes, and manually sorted under a stereomicroscope. Fourteen shells referable to the species treated here were recovered from this sample. No visibly living specimens were obtained, and therefore no molecular or anatomical analyses were attempted. A simple localisation map was prepared to show the position of the two French localities discussed in this study: Vabre de Malaga, Rognac, and the Parc national des Calanques locality reported by Dommergues & Gargominy (2024) (Fig. 1).
Fig. 1
Localisation of the French records of Truncatellina bourguignati (Coutagne, 1881) discussed in this study. (A) Position of the Bouches-du-Rhône department in southern France. (B) Detail of the Bouches-du-Rhône showing Vabre de Malaga, Rognac, corresponding to the type locality and newly sampled topotypic material, open circle, and the Parc national des Calanques locality reported as T. beckmanni by Dommergues & Gargominy (2024), filled circle.
Morphometric comparison was based on shell length and shell width (Fig. 2). Measurements of the French material were taken from calibrated photographs using ImageJ 1.54p. Shell length was measured as the maximum apical–basal dimension of the shell, and shell width as the maximum transverse diameter. These measurements were combined with the dimensions of the holotype of P. bourguignati recorded in Coutagne’s manuscript note, the holotype of T. beckmanni given by Quintana Cardona (2010), and individual published measurements of T. beckmanni and T. callicratis from Holyoak et al. (2012). The two specimens illustrated from the Calanques by Dommergues & Gargominy (2024) were also included in the comparison. Population means, ranges and standard deviations not assignable to individual specimens were excluded from Fig. 2.
Fig. 2
Morphometric comparison of shell length and shell width in Truncatellina beckmanni, T. bourguignati and T. callicratis. Shell length and shell width are expressed in millimetres. Circles correspond to specimens assigned to T. beckmanni, squares to T. bourguignati, and triangles to T. callicratis. Open black symbols indicate French specimens measured for the present study, whereas filled black symbols indicate comparative specimens taken from the literature. The red circle indicates the holotype of T. beckmanni Quintana Cardona, 2010, and the blue square indicates the holotype of T. bourguignati (Coutagne, 1881), based on Coutagne’s manuscript measurement
RESULTS
Recent litter sampling in the Vabre de Malaga (13340 Rognac, Bouches-du-Rhône; 43.48235, 5.24511) yielded 14 shells referable to the species treated here (Fig. 1). These shells match the morphology of the historical specimen preserved in the Coutagne collection and of the taxon here identified as Truncatellina bourguignati (Figs 3–10). The species is therefore confirmed to be still extant in its type locality.
Figs 3–10
Composite plate illustrating Truncatellina bourguignati (Coutagne, 1881): 3–4 – holotype by monotypy, MDC.45030705, Musée des Confluences, Coutagne collection, Vallon de Rognac; 5–6 – archival drawing attributable to G. Coutagne (MS 6J016), corresponding to the holotype; 7–8 – shell from the population of the Parc national des Calanques; 9 – in situ photograph of a shell from the same Calanques population; 10 – shell from Vabre de Malaga, Rognac. The scale bar equals 1 mm and applies to Figs 3, 4, 7, 8 and 10 only
Among the measured French shells, shell length ranged from 1.42 to 1.65 mm (mean 1.54 mm, SD = 0.06, n = 14) and shell width ranged from 0.82 to 0.97 mm (mean 0.90 mm, SD = 0.04, n = 14). The shell of the holotype of P. bourguignati measures 1.43 × 0.95 mm according to Coutagne’s manuscript note. The shell length/width comparison places the French material attributed here to T. bourguignati within, or close to, the morphometric space occupied by published specimens of T. beckmanni (Fig. 2). The holotype of T. bourguignati plots among the compact shells assigned to T. beckmanni. By contrast, the comparative T. callicratis specimens tend to show a more elongate shell for a similar or smaller shell width. This descriptive pattern supports the interpretation that the French topotypic material, the Coutagne holotype and the published concept of T. beckmanni refer to the same compact morphotype.
SYSTEMATICS
Truncatellina bourguignati (Coutagne, 1881), comb. nov., stat. rev. = Truncatellina beckmanni Quintana Cardona, 2010, junior subjective synonym, syn. nov.
Vernacular name. French name proposed: Maillotin trapu; English translation: “stout maillotin”. The adjective “trapu” refers to the short, broad and compact shell shape of the species compared with the more elongate shell of several other regional Truncatellina.
Protonym. Pagodina bourguignati Coutagne, 1881: 39–40.
Type locality. “Le vallon de Rognac”, Bouches-du-Rhône, southern France.
Type material. Holotype (by monotypy): France, Bouches-du-Rhône, Vallon de Rognac, “Rognac, alluvions”, collected between July and December 1880, G. Coutagne leg., one shell, Musée des Confluences, Coll. Coutagne, MDC.45030705 (Coutagne no. 834).
Additional material examined. France, Bouches-du-Rhône, Vabre de Malaga, 13340 Rognac, 43.48235, 5.24511, litter sample, 9 February 2026, L. Aureglia leg., collection no. LA1607, 14 shells; France, Bouches-du-Rhône, Parc national des Calanques, Vallon de la Gineste, 13009 Marseille, 43.2375, 5.48098, 26 September 2025, M. Marmier leg., 10 shells, one illustrated, shell height 1.5 mm, shell width 0.9 mm.
Type material of the junior synonym (from the original description). Holotype of Truncatellina beckmanni Quintana Cardona, 2010: shell deposited in the malacological collection of the Museu Diocesà de Menorca, registration number MDM-2703, from Lloc de Monges (Ciutadella de Menorca, Illes Balears); shell height 1.29 mm, shell width 0.79 mm.
Diagnosis. A very small, compact, strongly ribbed dentate species of Truncatellina, characterised by a short and broad shell, 5–6 strongly convex whorls, a deep suture, regular axial ribbing, a very narrow umbilicus, and a well-developed apertural dentition, notably with conspicuous parietal and palatal lamellae visible in frontal view. The species differs from T. callicratis by its more compact shell, lower height-to-diameter ratio, more strongly developed lamellae, especially the parietal and palatal lamellae, and more pronounced, regular ribbing. It differs from Pagodulina species historically associated with the name P. bourguignati by its truncatellinid shell shape and apertural barrier pattern.
Synonymy and nomenclatural history.
Isthmia – Coutagne, in litteris, 1881.
Pagodina bourguignati Coutagne, 1881: 30, 39–40, 51; original description and mention of the type locality.
Pagodina bourguignati – Locard 1882: 172.
Pupa pagodula – Westerlund 1887: 91, misidentification as a juvenile Pagodulina pagodula.
Pagodina bourguignati – Locard 1894: 327.
Pagodina bourguignati – Locard 1896: 215.
Pagodina bourguignati – Margier 1910: 44.
Pagodina pagodula – Germain 1913: 183, placed in synonymy.
Pagodulina (?) bourguignati – Tryon & Pilsbry 1926: 179, considered possibly a vertiginid and explicitly not a juvenile P. pagodula.
Pagodulina pagodula ? var. bourguignati – Germain 1930: 421, retained with doubt and considered possibly closer to Vertigo.
“Pagodina” bourguignati – Pilsbry 1934: 108, considered possibly referable to Truncatellina.
Truncatellina – Klemm 1939: 256, explicitly removed from Pagodulina.
Pagodulina austeniana austeniana – Pavon & Bertrand 2005: 39, treated as a synonym.
Pagodulina austeniana austeniana – Gargominy 2022, treated as a synonym in TaxRef.
Truncatellina beckmanni Quintana Cardona 2010: 149–158, described from Menorca.
Truncatellina beckmanni – Dommergues & Gargominy 2024: 1–3, reported from the Bouches-du-Rhône as new for France.
Description. Shell light brown to yellowish, relatively short and broad, giving it a compact appearance (Figs 3–10). It consists of 5–6 fairly rounded whorls, with a marked, deep suture. The aperture is subquadrangular, with a rounded lower part and provided with three well-developed lamellae: palatal, columellar, and parietal. Only the characteristic palatal and parietal lamellae are visible in frontal view, the columellar lamella ending before the peristome. The white palatal lamella is well-developed inside the shell and also visible in dorsal view. The peristome is discontinuous in the parietal region and reflected. The umbilicus is very narrow and not covered by the columellar margin. The shell surface bears thick, regular growth lines forming a characteristic ribbing.
Dimensions. Measured French material: shell height 1.54 mm, range 1.42–1.65 mm, n = 14; shell width 0.90 mm, range 0.82–0.97 mm, n = 14. Holotype of P. bourguignati: 1.43 × 0.95 mm according to Coutagne’s manuscript note, consistent with the dimensions given in the original description, 1.4 × 0.95 mm.
Habitat and ecology. The species appears to be associated with Mediterranean calcareous habitats, especially rocky or karstic slopes with limestone outcrops, screes, and accumulations of litter in sheltered microhabitats. At Vabre de Malaga, it was recovered from litter beneath a vegetation mosaic dominated by Viburnum tinus, Pinus halepensis, Smilax aspera, Ruscus aculeatus, and a few Quercus ilex. In the Calanques, it was found in a thermo-xeric shrubland on limestone with abundant stones and rock outcrops, in vegetation including Quercus coccifera, Salvia rosmarinus, Smilax aspera, and Asparagus acutifolius. The type locality in Menorca is likewise situated on calcareous substrate and was described as a small woodland with oleaster, juniper, and mastic. French habitats are illustrated in Figs 11–12.
Figs 11–12
Habitats of Truncatellina bourguignati (Coutagne, 1881) in southern France: 11 – habitat at Vabre de Malaga, Rognac, corresponding to the type locality; 12 – habitat in the Parc national des Calanques, at the site where the species was collected and reported by Dommergues & Gargominy (2024)
Distribution. Western Mediterranean, with a still insufficiently documented distribution. Under the present taxonomic interpretation, the species is known from Menorca, the southern Iberian Peninsula, and southern France. Published records attributable to this taxon exist from the Spanish provinces of Córdoba and Málaga, and from Portugal in Algarve, Estremadura, Ribatejo, and Beira Litoral. In France, it is currently known only from the Bouches-du-Rhône, in the Parc national des Calanques and at Vabre de Malaga, Rognac.
Remarks. Although the original description does not explicitly state the number of specimens examined, the archival documentation associated with G. Coutagne suggests that only a single shell was available to him. His collection notebooks (6J001 and 6J002) refer to only one specimen. In a letter dated 18 January 1881 (6J053) addressed to Bourguignat, Coutagne transmitted the specimen under the name Isthmia, which already indicates that he had recognised its truncatellinid affinities before publishing it in Pagodina. A manuscript drawing by Coutagne (6J016) matches the extant shell and gives dimensions of 1.43 × 0.95 mm (Figs 5–6). The specimen must therefore be treated as the holotype by monotypy, not as a syntype or lectotype.
The extant type specimen agrees closely with the shell morphology of Truncatellina beckmanni Quintana Cardona, 2010 and later documented by Holyoak et al. (2012), especially in its short and robust shell, its strong ribbing, its low height relative to diameter, and its marked apertural armature. The dimensions of the Coutagne shell (1.4 × 0.95 mm in the original description; 1.43 × 0.95 mm in the manuscript note) fall within the morphometric space occupied by specimens assigned to T. beckmanni in the present comparison (Fig. 2). Recent topotypic material collected in 2026 at Vabre de Malaga, corresponding to Coutagne’s historical Vallon de Rognac, matches the same taxon and confirms that the species is still extant at its type locality.
Because Pagodina bourguignati Coutagne, 1881 is the oldest available name applicable to this species, it has priority over Truncatellina beckmanni Quintana Cardona, 2010. The valid name is therefore Truncatellina bourguignati (Coutagne, 1881), and T. beckmanni is here treated as its junior subjective synonym, syn. nov.
DISCUSSION
This study resolves a long-standing taxonomic problem concerning a minute Mediterranean truncatellinid that had remained difficult to interpret for more than a century. Its main result is not the description of a new taxon, but the reassessment of an old available name through the combined use of historical material, archival documentation, newly collected topotypic shells and morphometric comparison with related material. The present results provide a direct link between the forgotten name Pagodina bourguignati Coutagne, 1881 and the species later described as Truncatellina beckmanni Quintana Cardona, 2010. The combined evidence from the extant historical specimen, Coutagne’s archival documentation, the manuscript drawing, and the newly collected topotypic material from the Vabre de Malaga (Vallon de Rognac) shows that a single, morphologically coherent taxon is involved. In particular, the archival documents remove any ambiguity concerning the type material by showing that Coutagne had only one shell at his disposal. The specimen preserved in the Musée des Confluences must therefore be regarded as the holotype by monotypy. Once this historical material is compared with the original concept of T. beckmanni as defined by Quintana Cardona (2010), the additional Iberian material documented by Holyoak et al. (2012), and the recent French material reported by Dommergues & Gargominy (2024), the treatment of T. beckmanni as a junior subjective synonym of T. bourguignati becomes the most parsimonious interpretation. The name introduced in 2010 therefore applies to the same species and must be treated as a junior subjective synonym of the senior name Truncatellina bourguignati (Coutagne 1881).
This conclusion is necessarily based on shell morphology. No molecular or anatomical analyses were conducted because the newly collected material consisted only of empty shells, with no visibly living specimens recovered from the litter sample. This is a limitation, especially in a genus where shell characters may show convergence or limited diagnostic resolution, but no shell character currently allows the French topotypic material, the Coutagne holotype and the published concept of T. beckmanni to be separated. This nomenclatural clarification has immediate consequences for the taxonomy and faunistics of the French malacofauna. First, it restores an overlooked nineteenth-century name to practical use and stabilises the nomenclature of this minute Mediterranean truncatellinid. Second, it shows that the French record published as Truncatellina beckmanni by Dommergues & Gargominy (2024) should now be referred to T. bourguignati (Fig. 1). The rediscovery of the species in 2026 in the Vabre de Malaga (Vallon de Rognac) is also noteworthy, as it confirms that the species is still extant in its type locality more than a century after its original description. The present paper is intentionally limited to this taxonomic and nomenclatural point. A broader revision of western Mediterranean Truncatellina, ideally combining detailed conchological comparison with molecular sampling, would nevertheless be valuable, especially given the recurrent problems of shell-based over-splitting and hidden synonymy documented in the genus (Holyoak et al. 2012, Kneubühler et al. 2020, Cucherat & Guiller 2021). Such a broader framework, however, is not required to establish the identity and priority of Coutagne’s name in the present case.
