Taxonomic clarification of three taxa of Iberian geomitrids , Helix montserratensis Hidalgo , 1870 and subspecies ( Gastropoda , Pulmonata ) , based on morpho – anatomical data

espanolHelix montserratensis (actualmente Xerocrassa montserratensis) es un geomitrido iberico descrito por Hidalgo en 1870 en Montserrat (Barcelona, Espana). Sobre la base de varios caracteres conquiologicos, se describieron dos taxones muy similares, como variedades de este taxon: Helix montserratensis betulonensis y otro menos nombrado, Helix montserratensis delicatula. Estas variedades, sobre todo betulonensis, se han considerado subespecies de X. montserratensis, aunque algunos autores las consideran especies diferentes, basandose en los datos anatomicos del aparato reproductor obtenidos de escasos ejemplares. Hemos revisado el material tipo y otras muestras procedentes de localidades donde se considera que estan presentes los tres taxones tratados. Se han estudiado con detalle las caracteristicas morfo–anatomicas de la concha y el aparato reproductor de los ejemplares. Los resultados obtenidos nos permiten aclarar el estatus taxonomico de X. betulonensis y de X. m.delicatula, que corresponden en realidad a X. montserratensis, y que deben ser consideradas sinonimos posteriores de esta especie. Finalmente, se vuelve a describir la concha de X. montserratensis y se muestra el mapa de sudistribucion geografica. EnglishHelix montserratensis (currently Xerocrassa montserratensis) is an Iberian geomitrid described by Hidalgo in 1870 from Montserrat (Barcelona, Spain). Two very similar taxa were described as varieties of this taxon based only on conchological characters: Helix montserratensis betulonensis and a less known taxon, Helix montserratensis delicatula. These varieties, especially betulonensis, were considered for a long time as subspecies of X. montserratensis, although some authors upgraded them to the rank of species based on anatomical data of the reproductive system in a few specimens. We review the type specimens and other samples of the three taxa collected at several localities where the three referred taxa are considered present. The morpho–anatomical characteristics of the shell and the reproductive system were studied in detail. The results allow us to clarify the taxonomic status of X. betulonensis and X. m.delicatula as X. montserratensis, indicating they should be considered junior synonyms of this species. Finally, the shell is redescribed and a map is provided showing the geographical distribution of X. montserratensis.

Bofill & Haas (1920) and Bofill, Haas & Aguilar-Amat (1921) mentioned these taxa at various localities in the basins of the Llobregat and Besós rivers.Hesse (1934) studied the reproductive system of X. montserratensis and Ortiz de Zárate (1946) described in detail the genitalia and the radula of specimens collected in Montserrat.Altimira (1971) elevated the variety betulonensis to the rank of species based on anatomical data of the reproductive system, although on few specimens.Puente (1994) made a bibliographic compilation and studied the anatomy, also of few specimens, from Montserrat, Gallifa and the Serralada de Marina, keep� ing the nomenclature proposed by Altimira (1971) as a valid and distinct species.
The three taxa were attributed to the genus Xerocrassa Monterosato, 1892, mainly by the pres� ence of a stimulator apparatus with two rudimentary dart sacs, without darts inside and atrial appendage (Forcart, 1976;Gittenberger, 1993;Puente, 1994;Martínez-Ortí, 1999;Martínez-Ortí et al., 2000) (figs. 4, 7).The first description of the reproductive system of a specimen of X. montserratensis was made by Hesse (1934: fig. 57), with material of L. Pfeiffer.Ac� cording to Hesse (1934), the flagellum is tiny (sic), a characteristic that differs considerably from that which this species in fact presents.This author pointed out that he only studied a specimen preserved in ethanol and as he wanted to preserve the shell, the dissection was incomplete, an opinion shared by Ortiz de Zarate (1946: pp. 348-349).Because the animal was deeply retracted inside the shell, the flagellum was probably sectioned as a result of an incomplete dissection.The flagellum, long and with many kinks in its retracted state, can fracture easily during its extraction (au� thor's observation).The anatomical data provided by Ortiz de Zárate (1946) and Puente (1994) concluded that Helix montserratensis belonged to the genus Xerocrassa, resulting in the combination Xerocrassa montserratensis, which remains today.The study of the reproductive system was key to considering X. montserratensis and X. betulonensis as different,valid species (Altimira, 1971;Puente, 1994).
Despite the remarkable scientific and conservation interest, the taxa studied in the present work have been subject, over the years, to ambiguous and sometimes contradictory considerations regarding taxonomy and nomenclature, emphasizing the need to elucidate their taxonomic status.
The inclusion of this species in the Red List of Threa� tened Species published by the IUCN with the category 'endangered B1ab(iii) + 2ab(iii)' (Martínez-Ortí, 2013) is of note.The species has been mentioned in several recently published works that refer to the effects of different disturbances in their populations (Santos et al., 2009;Bros, 2011;Bros et al., 2011;Santos et al., 2012).The taxonomic status of X. betulonensis and X. m. delicatula, in relation to X. montserratensis, also merits clarification for conservation reasons.

Shell characters
We examined the type material of the three taxa.The type series of H. montserratensis consists of a syntype that is deposited in the Muséum d'Histoire Naturelle, MNHN, of Paris with the accession number MNHN-23274.It is considered herein as lectotype (ICZN, 1999: Art. 74.1.1).The type locality corres� ponds to 'Montserrat' (province of Barcelona).Another syntype should be in the Hidalgo collection deposited in the Museo Nacional de Ciencias Naturales of Ma� drid, but it has not been found (Fischer-Piette, 1950;Templado et al., 1993: p. 285).
The type series of Helix montserratensis var.betulonensis includes a syntype which was designated as lectotype by Martínez-Ortí & Uribe (2008).It is deposited in the Bofill collection in the Museu de Ciències Naturals de Barcelona, with the code MZB 81-4808, its locus typicus being "En las inmediaciones del Besós, hacia Badalona, Santa Coloma" (around the Besós River, towards Badalona, Santa Coloma).

E T W BL W E L W
The type series of H. montserratensis var.delicatula includes five syntypes deposited in the Artur Bofill collection in the Museu de Ciències Naturals de Barcelona, MCNB with the code MZB 81-4766 [Martínez-Ortí et al., (in press)].The locus typicus is 'La Mata, San Llorenç del Munt', Barcelona pro� San Llorenç del Munt', Barcelona pro� vince (Bofill, 1898).This locality corresponds to the mountain of Montcau, close to la Mata ("al dirigirnos desde la Mata a la cumbre y pasando por la pudinga característica de la montaña")("…going towards the top of la Mata passing through the characteristic pudding stone" (Bofill, 1898: p. 335).
A lectotype of this variety has been designated by Martínez-Ortí et al. (in press) with the code MZB 81-4766-A, in parallel to four paralectotypes .
Various conchiological characters of 73 specimens (see annex) and the anatomy of the reproductive system of 17 specimens were studied.Three major shell characters were used by Bofill (1879Bofill ( , 1898) ) to differentiate H. montserratensis and its varieties betulonensis and delicatula: 1) the different size in shell diameter; 2) the regularity, dimensions and number of ribs on the surface of the shell; and 3) the spire being flatter in X. betulonensis than in X. montserratensis.
The number of ribs was estimated from three areas of 2.0 mm each in length and easy to locate (fig.1).
One of them is between the end of the third whorl and the beginning of the fourth whorl (ETW), another is at the begining of the last whorl from the peristoma (BLW), and the third is at the end of the last whorl (ELW).
The spire is considered the height of the shell between the apex and the begining of the last whorl.
The shell and the reproductive system were measu� red using stereomicroscopy with a trailer micrometer.Detailed studies of the protoconch and the ribs of the teleoconch were made in the MEB S-4100, at the S. C. S. I. E. of the University of Valencia.

Reproductive system data
Thirteen specimens were measured, accounting for their reproductive system characters.Three of them correspond to X. m. montserratensis and come from two locatities: the locus typicus and 'Els Munts'.Two more specimens were measured to scale on the fi� gures provided by Ortiz de Zárate (1946) and Puente (1994).Two specimens came from the typical locality (Montcau) of X. m. delicatula and eight specimens of X. betulonensis came from another three localities: Santa Coloma de Gramanet (locus typicus), Sentme� nat, and Gallifa.Some of the anatomical data of the reproductive system of X. m. montserratensis and X. betulonensis should be considered approximate because they were obtained by measuring the organs to scale on the figures drawn by Puente (1994: plate XXII and plate XXIII, respectively) and Ortiz de Zárate (1946: fig.5) for X. montserratensis.
We performed the dissection of these specimens, drew some of the genitalia and measured several organs (figs.5, 7).
Among the anatomical characters of the repro� ductive system we paid special attention to those used by Ortiz de Zárate (1946), Altimira (1971) and Puente (1994) to differentiate X. betulonensis from X. m.montserratensis.We measured the penis according to Ortiz de Zárate (1946) and Altimira (1971), and also Puente (1994), who focused only on the more thicke� ned portion of this organ, i.e. the proximal penis (fig.6: Pep), not taking into account the less thickened and distal portion (Ped), which reaches the muscle retractor of the penis.The same occurs with the epiphallus, considered by these authors as the addition of the distal penis (Ped) and the epiphallus (Ep).
Given the difficulties in finding mature specimens in the field, one specimen of X. betulonensis from the locus typicus was kept in captivity for several months until it reached sexual maturity.

Results and discussion
Shell: conchological characters and morphometric data (figs. 2-3, 5-6, 8-9) Diameter measures obtained on 73 specimens are summarized in table 1. Figure 8 shows the relation� ship between height/diameter (H/D) from which we can deduce that the majority of these specimens keep a high similarity between the three taxa.These    comparisons demonstrate that the diameter of the shell and it H/D, relationship do not allow a proper taxonomic identification between these three taxa.
In addition, it is verified that the diameter of most shells of the three nominal taxa varies between 8.0 and 11.0 mm (annex).
Exceptionally, a specimen of X. betulonensis of Gallifa presented 33 ribs in the end of the third whorl, while the other nine studied shells of this locality reached 24 ribs, a number that matches the rest of taxa.These data indicate that rib number should not be considered valid to differentiate the three taxa.
The spire data are summarized in table 3.Only three examined of 20 X. montserratensis specimens studied exceeded 1.1 mm, corresponding to the maximum value obtained for X. betulonensis (annex).These data do not allow differentiation of the taxa, although the spire of X. montserratensis and X. m. delicatula can be a little higher than the spire of X. betulonensis in some cases (annex).

mm
The shells of the population of Els Munts assigned by Altimiras et al. (2005) to X. montserratensis show a more globose shape than the rest of the populations, with a range of height/diameter ratio (n = 10) between 0.614 and 0.701 (figs.2J-2L; table 1), while for the examined population coming from the locus typicus (Sant Jeroni) it varies between 0.512 and 0.694 The carinate periphery of the shells of Els Munts population is little marked, unlike what is seen in X. montserratensis and X. betulonensis, where it is more evident.However, we do not consider these  differences sufficiently relevant to differentiate them taxonomically from other known populations of X. montserratensis.About X. m. delicatula, we examined 15 specimens from two locatities [La Mata (locus typicus) and Montcau] obtaining values (H/D) ranging between 0.504 and 0.618.Finally, for X. betulonensis, we examined 37 specimens, and the range was bet� ween 0.489 and 0.666, from three localities (annex).
Reproductive system: morphometric data (figs.4, 7) Tables 4 and 5 show the measures of different genital organs of 13 specimens.One of our specimens of Gallifa was aphalic (fig.7B).
We carried out measurements following two criteria: for the penis and the set of its two anatomical parts   Ortiz de Zárate (1946) considered that in X. m. montserratensis the flagellum is equal to or slightly higher than the epiphallus in X. betulonensis, consi� dering also as part of the epiphallus the thin and distal portion of the penis (EpPed).This criterion is not met in all cases, finding flagela in X. m. montserratensis, that are shorter than the older measures of the epiphallus obtained in X. betulonensis (tables 4-5).Therefore, we do not consider that this criterion is valid to diffe� rentiate the two taxa.
Later, Altimira (1971) differentiated X. betulonensis from X. m. montserratensis by the epiphallus being shorter than the flagellum and also presenting two     trifid mucous glands, while X. m. montserratensis has a longer epiphallus than the flagellum, and does not present trifid mucous glands.Puente (1994) found bifid mucous gland trunks in two examined specimens of X. betulonensis and also saw specimens with the epiphallus shorter than the flagellum but longer in the other specimen [epiphallus sensu Altimira (1971) and Ortiz de Zárate (1946)].These results of Puente (1994) questioned the use of these two morpho-ana� tomical characters to discriminate these two taxa.
In our specimens of X. betulonensis, the mucous glands generally present 3 or 4 bifid trunks, not finding any trifid, as in X. m. montserratensis, as already noted Puente (1994); this corroborates our criterium not to consider it as an anatomical feature with taxonomic value.
As regards the second character, as also already noted by Puente (1994), we found great variability in the lengths of the two organs for both taxa.Conse� quently, we neither consider this character as valid to differentiate these taxa.We also measured the last taxonomic character taking into account the penis in that allow us to use this measurement to differentiate these taxa (tables 4-5).However, Puente (1994), with only two specimens, found differences in four anatomical characters of the reproductive system to differentiate X. m. montserratensis from X. betulonensis: 1) the ratio of flagellum/length of the complex penis+epiphallus (F/Pe + Ep); 2) the length of the epiphallus (Ep) and its ratio with the penis (Pe); 3) the ratio between the diameter of the dart sacs and of the mucous glands; and 4) the length and thickness of the vagina.For the ratio of the flagellum/length of the complex penis + epiphallus (F/Pe + Ep), Puente (1994) indicated that it was greater in X. betulonensis (0.5-0.9) than in X. montserratensis (0.5).Our results for X. montserratensis vary between 0.52 and 0.78, clearly exceeding the value given to this species by Puente (1994).For X. betulonensis, the value of the F/Pe + Ep varies between 0.61 of a specimen of Gallifa and 1.63 of a specimen from the type locality (table 5).For X. m. delicatula this value varies between 0.64 and 0.74.The dispersion of values obtained in this study allows us to consider this as a non-valid character to discriminate the taxa.
Regarding the epiphallus (in the sense of Altimira and Ortiz de Zárate, Ep + Ped), it has been alleged that it is 3-4 times longer than the penis (Pep) in X. betulonensis, while in X. m. montserratensis it is 5 times longer (Puente, 1994).
In our three specimens of X. m.montserratensis the results vary between 2.85 and 3.75 times, for 2 speci� mens of X. m. delicatula between 2.11 to 3.02 times, and for 7 specimens of X. betulonensis varies between 2.16 and 5.6 times.Again, these results do not allow us to consider this criterion valid to differentiate these three nominal taxa, which do not conform to the values proposed by Puente (1994, tables 2-3).Nevertheless, we made the same calculation for the ratio Ep/Pe, with the penis being up to the retractor muscle, and the results vary for X. m. montserratensis between 1.57 and 2.61, for X. betulonensis between 1.41 and 3.59 times, and for X. m. delicatula between 1.04 and 1.39  Altimira (1971).(Para las otras abreviaturas, véase tabla 4.) X. betulonensis Puente (1994) LT ( 1) LT ( 2) S ( 1) S ( 2) Between the diameter of the dart sacs and that of the mucous glands, Puente (1994) indicates that the ratio tends to be 1 in X. betulonensis and smaller in X. montserratensis.
We obtained values for 2 specimens of X. m. montserratensis that vary between 0.62 and 0.77 mm, and between 0.55 and 1.2 mm for 8 specimens of X. betulonensis.Two specimens of X. m. delicatula varied from 0.71 to 1.14 mm (tables 4-5).The data confirm that neither is this character sufficiently valid to differentiate the studied taxa.
Finally, Puente (1994) indicates that the vagina is long and thin in X. montserratensis, but shorter and thicker in X. betulonensis and X. betulonensis.Data from our study are summarized in table 6.Only one specimen of X. montserratensis presented notable dimensions, 0.6 x 3.8 mm.In some specimens of X. betulonensis, the vagina is longer and thinner although in other specimens it is shorter and thicker, indicating intra-population variability.These data, like the rest of the characters proposed by Puente (1994), show that this relationship does not clearly differentiate some of the taxa studied.The remaining anatomical characters, such as the length of the free oviduct, the atrium, the length of the dart sacs, the penis, the penis diameter, and the bursa copulatrix' duct and its dimensions, do not allow us to discriminate any of the taxa treated (tables 4-5).
An exception was found with an aphallic specimen of Gallifa (table 5: specimen nº 4; fig.7B).In the same specimen a metacercariae of a digenean tre� matode of the family Brachylaimidae Joeux et Foley, 1930, was found lodged in the kidney, an organ that is usually next to the hepatopancreas, pericardial cavity and pedal gland in land snails (Manga, 1983;Bargues, 1986).Its relevance stems from the fact that is the first record of a brachylaimid trematod in metacercariae stage in X. montserratensis, a parasite of small mammals, using this species as an intermediate host.

Taxonomical clarification
Results obtained according to morpho-anatomical characters and measures from both the shell and reproductive system show that taxonomical criteria used so far to discriminate the three studied taxa should not be considered.The results show the scarce variability in the measures obtained from the shells and from the different organs of the repro� ductive system which have been traditionally used to discriminate these three taxa.This allows us to establish the correct taxonomic status of the three taxa, X. m. montserratensis, X. m. delicatula and X. betulonensis, that actually correspond to a unique species, X. montserratensis.Thus X. betulonensis and X. m. delicatula are junior synonyms of Xerocrassa montserratensis (Hidalgo, 1870) because they were described subsequently.
Redescription of the shell de Xerocrassa montserratensis (Hidalgo, 1870) Redescription based on the study of 73 shells of three taxa: X. m. montserratensis (n = 21), X. m. delicatula (n = 15) and X. betulonensis (n = 37) (figs.1-3, 5-6; annex): shell from 4 to 5¾ whorls, of regular growth, below convex and above flattened, light brown, grey and sometimes whitish.The dimensions vary between 6.1 and 14.0 mm in diameter and between 4.1 and 7.0 in height.The shape varies according to the locality of origin: it can be conically depressed, with a highly convex base, more globose in some places.The protoconch shows up to 1⅝ whorls, with a 1.25 mm maximum diameter and surface with spiral ornamen� tation.The apical area, and sometimes the umbilicus, presents a dense and regular pattern, costulated or ribbed, with between 11 and 33 ribs in the area of greater density, at the begining of the third whorl.In the last whorl it presents a marked peripheral carinate that is more subtle in some localities.The umbilicus goes from slightly wide to narrow, varying between 1.35 mm and 3.1 mm.The aperture is rounded-oval, sometimes slightly angled.The peristome is acute, with patent thickening inside of whitish colour in adult specimens.

Geographical distribution
Xerocrassa montserratensis is currently distributed in the province of Barcelona (fig.9): the 'Serralada Prelitoral Catalana' (Montserrat, Sant Llorenç del Munt, Serra de l'Obac, Gallifa, Puig de la Creu, El Farell and Guilleries), Serralada de Marina, Collse� rola and surroundings.About the populations on this species in the province of Girona, in Viladrau, region of Osona (Altimiras et al., 2005), we visited the area and we only found very old, damaged shells that do not confirm their current presence.In the province of Tarragona in Altafulla and Roda de Berà (Altimira, 1971), as shown later, we have no definitive data that corroborate its current presence.
After having prospected many specimens in the present study, we only found living specimens in the studied localities and its surroundings.We are unaware of evidence that living individuals have been found in recent times in the mountains of Collserola (Bros, 2004(Bros, , 2009;;Torre et al., 2014).
For biogeographical purposes, we have included bi� bliographic references that mention this species found in sediments of riverbanks in quaternary deposits; it is not always specified whether the samples correspond to live specimens or only shells or subfossils.
One sample of X. montserratensis deposited in the malacological collection at the Natural Sciences Museum of Barcelona is linked to locations far from the aforementioned distribution area.Two labels inside the sample convey incoherent information about the geographic origin of this record: Roda de Berà and Altafulla, two locations separated by some 10 km between them (both in Tarragona province).We visited the area and thoroughly sampled suitable habitats for X. montserratensis but we did not find any specimen attributable to this taxon.We conse� quently reject this information.

Fig. 1 .
Fig. 1.Shell of Xerocrassa montserratensis showing the three studied areas on its surface: BLW.Beginning of the last whorl from the peristoma; ELW.End of the last whorl; ETW.End of the third whorl and beginning of the four whorl).

Table 1 .
Measurements of the shell diameter of specimens of the three taxa in mm: Min.Minimal value; Max.Maximum value; x̄.Mean; SD.Standard deviation; n.Number of specimens.

Table 2 .
Number of ribs for each sampled zone in specimens of the three taxa.(For abbreviations see table 1.)

Table 3 .
Measurements of spire of the specimens of the three taxa in mm.(For abbreviations see table 1.)

Table 6
Measurements of the vagina in mm.Abbreviations: VgD.Diameter of vagina; VgL.Length of vagina; n.Number of specimens.