On the Monacha species of Lebanon (Gastropoda, Hygromiidae)

Abstract In this paper, all seven hitherto known species of the hygromiid genus Monacha from Lebanon are briefly characterised and illustrated, and distribution maps are supplied (Monacha (Monacha) syriaca (Ehrenberg, 1831), Monacha (Monacha) nummus (Ehrenberg, 1831), Monacha (Monacha) obstructa (L. Pfeiffer, 1842), Monacha (Monacha) crispulata (Mousson, 1861), Monacha (Monacha) solitudinis (Bourguignat, 1852), Monacha (Monacha) bari Forcart 1981, and Monacha (Monacha) cf. compingtae (Pallary, 1929)). One species, Monacha (Monacha) bari Forcart, 1981, is recorded for the country for the first time, and its relationship to Monacha (Monacha) compingtae (Pallary, 1929) is discussed. Based on recently collected specimens, the genital organs of a long time ignored species, Helix solitudinis Bourguignat, 1852 could be investigated. It is here re-described as a Monacha species endemic for Lebanon.


Introduction
The malacofauna of Lebanon has been the focus of malacologists since quite early on. Among the earliest scientists collecting molluscs in this country, the famous German zoologists Friedrich Wilhem Hemprich and Christian Gottfried Ehrenberg from Berlin, who visited the area during their second voyage from 1821-1825, have to be mentioned. Their results were subsequently published by Ehrenberg (1828Ehrenberg ( -1833. Since then, the country has been the target of many expeditions where zoological and/or botanical objects were collected. Already at that time, Beirut served as "headquarters" for collectors, and thus, nearby and easily accessible places like Wadi Beyrouth or Wadi Nahr el Kelb became type localities of dozens of species. At the beginning of the 20 th century, a French expedition lead by Henri Gadeau de Kerville collected an enormous amount of continental molluscs from Syria in the wider sense, which were treated in two large volumes by Germain (1921). These specimens are housed in the MNHN in Paris. Later, the French malacologist Pallary, a keen connoisseur of the malacofauna of Northern Africa and home-based in Oran, Algeria, published some papers on the wider Palestinian area (Pallary 1929(Pallary , 1939. Finally, the famous Lebanese zoologists Henriette and George Thomé presented a small comprehensive volume covering the terrestrial malacofauna of Lebanon ( Thomé and Thomé 1988). Since then, no papers dealing exclusively with Lebanon have been published, and occurrences of continental molluscs have only been mentioned as by-products in papers having another scope. Quite recently, Bössneck (2011) reported on the results of his field trip to the country, where he (among others) mentioned two interesting species of Monacha from the Lebanon Mountains. These findings stimulated the present authors to amend these records with the results of their own research.
In Turkey, there is a large variety of species of the genus Monacha, where currently 54 species are known, with still several species remaining undescribed because of the low number of specimens available, or of lack of anatomical data (Hausdorf 2000). Nonetheless, the mountains stretching towards the south house a few more species of the genus, some of them are endemic, not well studied as of today, and have been only inadequately illustrated thus far. It is also our aim to raise awareness of this more or less ignored group of invertebrate animals living in Lebanon to local people, laymen as well as students.

Material and methods
This paper summarises data obtained during two excursions by the authors in Lebanon in 2008 and 2011, and others by Bariche during the last years. Specimens were collected by hand, and stored in the respective institutional collections. The section "specimens examined" contains only information that has been personally confirmed by the authors, i.e. none of the records have been retrieved from the literature. The records of Boessneck have been verified by Hausdorf (and a few by Neubert), and have been added to the distribution data. Finally, it also includes all data related to the Monacha species from Lebanon, its vouchers can be found in the Pallary collection housed at the AUBM. All specimens were checked by Neubert during his visit at the AUBM in October 2011. Unfortunately, the whereabouts of the Thomé's collection remains unclear. Inquiries at the MHNG, at the MNHN, and even personal contact of M. Bariche with the Thomés' yielded no clarification. Thus, the voucher specimens listed in the book by Thomé and Thomé (1988) are not available at the moment.
All measurements in mm.  Diagnosis. shell depressed, with two white spiral bands, malleate teleoconch sculpture, aperture reinforced by a strong white lip, apertural rim deep red, umbilicus closed by columellar callus.

Abbreviations for institutions AUBM
Description. shell depressed, with an elevated broad conical spire, basic shell colour deep brown to yellowish brown, usually with a white subsutural band and a second white band at the shell's periphery; two protoconch whorls, smooth; teleoconch with a malleate sculpture (i.e. looks like markings of a small hammer) and very fine radial growth lines, surface with a glossy shine; last whorl rounded to slightly compressed forming a blunt shoulder; last whorl abruptly bent towards the aperture; aperture oval and depressed, reinforced by a strong white lip; apertural rim sharply bounded, usually deep red to brownish; umbilicus always closed by a small columellar callus.
Distribution. This species is found widespread along the coastal areas in Lebanon. It usually lives at lower altitudes, but can occasionally be found up to 1000 m in more sheltered areas such as in the bottom of deep valleys.
Remarks. This species cannot be mistaken for any other species in the area due to its characteristic colour pattern, teleoconch sculpture, and closed umbilicus. Diagnosis. shell large, biconvex, periphery with a sharply bounded keel, umbilicus narrowly opened, broad periomphalum.

Monacha
Description. shell large and flat, biconvex, shell colour grey to brown; protoconch consisting of two smooth whorls; teleoconch whorls with a dense pattern of white ribs, that extend to the glossy underside of the shell; suture marked by a white sutural thread; ca. six regularly increasing whorls, periphery with a sharply bounded crimped keel, sometimes spire stepped because of whorls attaching somewhat below the keel Diagnosis. shell small, cream white, aperture with thick white labial callus, umbilicus closed, forming a characteristic funnel-shaped "pseudo-umbilicus".
Description. shell medium sized, spire broadly conical and somewhat elevated; protoconch consisting of 1.5 smooth whorls; teleoconch cream white, with faint riblets and a malleate sculpture (compare to M. syriaca), and evenly rounded whorls; last whorl slightly bending towards the aperture; aperture broadly oval, reinforced by a thick white labial callus, well discernible from the outside as a thick white callosity; peristomial rim sharply bounded, red; umbilicus closed, but last whorl forming a characteristic funnel-shaped "pseudo-umbilicus".
Measurements (Fig. 9): H = 6.68; D = 11.83; PH = 4.2; PD = 5.85. Distribution. In Lebanon this species seems to be quite restricted, probably because it is confined to more arid or steppe-like areas like central Syria, where it is one of the most abundant snail species. These environmental conditions are not present in the western part of Lebanon with its humid and steep mountain slopes. However, it is the most widespread species within Monacha. Its distribution ranges from Egypt to Pakistan, and Turkey to Saudi Arabia (Neubert 1998), probably because it can be easily distributed by human activities.
Remarks. This species is unmistakable for its funnel-shaped "pseudo-umbilicus". Subadult shells can be differentiated from M. syriaca by the uniformity of its cream white shell. Description. shell small, spire slightly elevated; protoconch consists of 1.5 smooth whorls; teleoconch greyish to brownish, with strong axial ribs, whorls covered by a dense sculpture of small granules and very long, soft hairs; hair scars visible even in eroded shells; suture moderately deep; last whorl slightly bending towards the aperture; aperture broadly oval, reinforced by a white lip (discernible from the outside); Distribution. This seems to be a rare species in Lebanon. It has probably been overlooked because of its small size, or even misidentified, because its hairs can easily fall off, and the remaining shell is less characteristic. It is possible that this species is more widespread.

Monacha
Diagnosis. shell medium sized, with a white spiral band at the periphery of the last whorl, aperture subrectangular, umbilicus open, cylindrical, penial papilla large and stout, flagellum longer than epiphallus.
Re-description. shell medium sized, spire depressed; protoconch consists of 2 smooth whorls; shell colour light brown to yellowish brown with a white spiral band at the periphery of the last whorl; teleoconch with a malleate sculpture and fine axial riblets; suture deep, simple; teleoconch with up to seven densely coiled whorls; last whorl slightly bending towards the aperture; aperture broadly subrectangular, reinforced by a small white lip; peristomial rim sharply bounded, simple; umbilicus open, cylindrical, a triangular columellar callus is indicated.
Genital organs (Figs 12a, b): The only specimen that could be investigated was quite strongly contracted; it is a species of Monacha sensu str., because the genitalia show an appendicula, but the penial retractor muscle is missing. Penis very short (0.8 mm), penial papilla large, stout with a central perforation completely filling the atrial lumen (preservation artefact?), basis of the papilla with a strong collar (Fig. 12b); epiphallus a thick-walled tube, its lumen filled with several finely crenulated pilasters (1.9 mm); flagellum short (2.1 mm), but surmounting the length of the epiphallus; appendicula (4.9 mm) branching off the atrium, subdivided in a thicker basal part, and a shorter part with a narrower lumen; two glandulae mucosae poorly ramified, inserting in the middle of the vagina; vesicle of bursa copulatrix large, hammer-like, pedunculus quite long (4.7 mm); atrial lumen with two pilasters, one of them large, knob-like, the other narrow and elongate; right ommatophoran retractor passes left to the genital organs.
Measurements Distribution. This species has only been recorded from two localities in Lebanon so far. The type locality Baalbek is not too far away and they were probably collected  on the way towards Baalbek. Both new localities are in the central chain of Mt. Lebanon at high altitudes. The habitats are characterised by coarse limestone boulders with interspersed subalpine grassland vegetation and is covered by snow during winter. In October 2011, two living animals were found actively crawling over the rocks (ca. 10°C and heavy rainfall), while in August 2008, only dead shells were encountered.
Differential diagnosis. This species differs from all other species in the Levante area by the shape of its umbilicus, which is cylindrical like a borehole. All other Monacha species with an open umbilicus deeply differ by either having a keeled (M. nummus) or a smaller and hairy shell (M. crispulata). Monacha bari and M. compingtae are conchologically similar to M. solitudinis, but these species have a narrow and almost closed umbilicus (refer to the discussion of M. bari). Information on the genital organs of the two latter species is scarce, only Hausdorf (2000: 84) reported on a subadult specimen of M. compingtae from southern Turkey. In this species, the penial papilla is short (large but stout in M. solitudinis), the epiphallus is longer than the flagellum (vice versa in M. solitudinis), and the appendicula is much shorter than in M. solitudinis. The specimen figured by Boessneck (2011) was re-investigated here; it matches the type specimen from Baalbek quite well, it is somewhat larger than the specimens from Falougha.
Remark. The correct generic affiliation of this species remained unclear until now. In his original description, Bourguignat compared it to his Helix camelina, which is a species of the Oxychilidae; this text was uncritically copied by Pfeiffer (1859). Gude (1902) was the first to list it under the genus Monacha, but without any justification for doing so. Germain (1921), who remarked that this affiliation needs to be corroborated by an investigation of the genital organs, shared this point of view. Later, Pallary (1939)  Diagnosis. shell small, spire slightly elevated, teleoconch has a faint white spiral band and fine axial riblets, umbilicus narrow closed by columellar callus.
Description. shell small, spire conical, slightly elevated; protoconch consists of 1.5 smooth whorls; shell colour light brown to reddish brown, sometimes with a faint white spiral band at the periphery of the last whorl; teleoconch with fine axial riblets and a pattern of fine spiral threads (only visible under higher magnification); suture deep, simple; teleoconch with up to seven tightly coiled whorls; last whorl slightly bending towards the aperture; aperture broadly oval, reinforced by a white lip; peristomial rim sharply bounded, simple; umbilicus narrow, closed by a triangular columellar callus.
Distribution. This species is here recorded for the first time for Lebanon. It seems to be restricted to higher altitudes up to the alpine region of the highest mountains in the Eastmediterranean. Remarks. The coordinates of the type locality of M. bari given by Forcart are erroneous, in fact they should be approximately at 33.3088°N, 35.7596°E. After careful examination of the paratypes of M. bari from the collection of Forcart (housed in the Natural History Museum in Basel, Switzerland), the recently collected specimens from Lebanon are here identified with this species. It is not possible to find any shell character that could justify a separation of the populations on specific level.  (Pallary, 1929). We were able to check the specimen figured by Boessneck (2011, Fig. 5a) from Aammiq in order to compare it to the species we finally identified as M. bari. Both species differ by the possession of a white subsutural spiral band in Monacha cf. compingtae (not seen in any specimen of M. bari), and the teleoconch sculpture, which is almost malleate in Monacha cf. compingtae, while M. bari shows axial riblets combined with spiral threads.

Monacha
Monacha compingtae was described from Tartus and Safita, both localities from the coastal area in southern Syria. Later, Pallary (1939) extended the distribution area of M. compingtae with more records from Syria ("kilomètre 139 de la route de Lattaquié à Alep" = probably somewhere NE of Idlib), "Koubba Cheikh Mokbel", "entre Lattaquié et Kerdaha" and "Slenfé (Nahib Younès" = Slinfah 35.583°N, 36."°E)). Hausdorf (2000: 84) reported this species from the Hatay area in southern Turkey, which constitutes the northern part of the eastmediterranean mountain ridge. In fact, this species is conchologically very similar to M. compingtae, the two white spiral bands are already mentioned by Pallary in the original description. However, he also mentions a transversal striation on the shell, which is not seen on the specimen from Aammiq. It might well be that this taxon from Lebanon represents another yet undescribed species.