taxonID	type	description	language	source
72141214A557FFACCE5AFD1DA741FCB9.taxon	description	(Figs 2, 22 – 24, 40 – 42) (1) A t r i u m a n d d i l a t e d o v i d u c t (Figs 2, 40) The upper, muscular atrium is smaller and not nearly as swollen and muscular as in A. ater s. l. Instead, the distal genitalia are dominated by a strong dilated oviduct. The thin oviduct connecting proximally to this muscular part is similar to that in A. ater s. l. (though usually shorter). Instead of the strong atrium retractor of A. rufus, a strong retractor inserts onto the distal part of the dilated oviduct. (2) I n s e r t i o n o f d u c t s (Figs 23, 40) Epiphallus and bursa-duct enter the upper atrium proximally, inserting onto a lateral bulge of the atrium just beside the insertion of the dilated oviduct. In a specimen opened as described above, these insertions are thus visible, posterior to the oviduct insertion, without having to detach any genital retractor muscle (although in mature specimens, the bursa and / or the spermoviduct may have to be pushed aside). In contrast to the triangular arrangement in A. rufus, the insertions of oviduct, epiphallus, and bursa-duct lie roughly along a straight line (in that order). (3) L i g u l a (Figs 2, 22 – 24, 41) The ligula is in the dilated oviduct. If the slug has been opened as described above, and no genital retractor cut, before we open the oviduct the ligula base is on the wall of the oviduct lying upwards, away from the body wall. A cut along the oviduct in line with the retractor muscle allows one to turn over the ligula (Figs 2, 41), which should then be fully visible and undamaged. The ligula is not bent and folded up as in A. ater s. l. but extended along the length of one side of the dilated oviduct; in comparison with A. ater s. l., one flank of the base is missing. The insertion of the thin oviduct is at the proximal end of the ligula base. The ligula takes the shape of a long boat with the ligula base corresponding to the bottom of the boat, the flange its sides. and the bow pointing towards the atrium (DAVIES 1987). Our illustrations (Figs 24, 41) show the distal end of the oviduct orientated downwards (Figs 24, 41), so we will refer to the flange on the left side of the boat as the right flange (we imply no homology with the left and right flank in A. ater s. l.). The width of the flange is asymmetric, though much less so than in A. ater s. l., and it is also generally narrower and varies less between specimens. The right flange is thicker and stronger than the left but forms only a bulge rather than the prominent flap in A. ater s. l. At the proximal end (the stern of the boat), the flange running closely around the opening of the thin oviduct is very narrow. The opening of the thin oviduct is directly underneath its insertion: there is no tunnel running through the ligula base. The most prominent ligula structure is the bow of the boat, where both longitudinal folds meet distally and project as a thick tongue into the atrium (Fig. 41); this tongue is attached only within the dilated oviduct. In a few individuals, a small single or double fold extends along the base, reminiscent of the two folds flanking the funnel-like structure on the right flank of the ligula in typical FR and BR. (4) Posterior lip and associated ridge (Figs 22, 23, 41) A ridge, generally less prominent in A. vulgaris than in A. ater s. l., leads to the opening of the bursa-duct, where it expands and forms a loop. This creates the spoon-shaped structure that ALLGAIER (2014) referred to as the posterior lip. The other end of the spoon continues as a small longitudinal fold towards the lower atrium. (5) E p i p h a l l u s (Fig. 42) The inner wall of the distal epiphallus contains longitudinal rows of big tubercles which are usually arranged in 5 – 6 well-ordered rows. Sometimes there are only 2 or 3 rows of big tubercles, and in this case there may be a few additional rows of smaller tubercles.	en	Reise, Heike, Schwarzer, Anne-Katrin, Hutchinson, John M. C., Schlitt, Bettina (2020): Genital morphology differentiates three subspecies of the terrestrial slug Arion ater (Linnæus, 1758) s. l. and reveals a continuum of intermediates with the invasive A. vulgaris Moquin-Tandon, 1855. Folia Malacologica 28 (1): 1-34, DOI: 10.12657/folmal.028.001, URL: http://dx.doi.org/10.12657/folmal.028.001
72141214A544FFA0CDCCFED1A590FD59.taxon	discussion	LINNAEUS (1758: 652) described both A. ater and A. rufus. If we consider these taxa as conspecific, which name has priority depends on the first reviser. Already MÜLLER (1774: 2) treated ater as having priority, but he did not mention the name rufus (he used the earlier name subrufus for what LINNAEUS (1758) called rufus), so cannot count as a reviser. At latest, FLEMING (1822: 572) explicitly treated A. rufus as a variety of A. ater, and this is the priority consistently followed by others who consider the taxa conspecific.	en	Reise, Heike, Schwarzer, Anne-Katrin, Hutchinson, John M. C., Schlitt, Bettina (2020): Genital morphology differentiates three subspecies of the terrestrial slug Arion ater (Linnæus, 1758) s. l. and reveals a continuum of intermediates with the invasive A. vulgaris Moquin-Tandon, 1855. Folia Malacologica 28 (1): 1-34, DOI: 10.12657/folmal.028.001, URL: http://dx.doi.org/10.12657/folmal.028.001
72141214A544FFA0CDCCFED1A590FD59.taxon	discussion	The nominotypical	en	Reise, Heike, Schwarzer, Anne-Katrin, Hutchinson, John M. C., Schlitt, Bettina (2020): Genital morphology differentiates three subspecies of the terrestrial slug Arion ater (Linnæus, 1758) s. l. and reveals a continuum of intermediates with the invasive A. vulgaris Moquin-Tandon, 1855. Folia Malacologica 28 (1): 1-34, DOI: 10.12657/folmal.028.001, URL: http://dx.doi.org/10.12657/folmal.028.001
72141214A544FFA0CDCCFED1A590FD59.taxon	discussion	is our AR morphotype,	en	Reise, Heike, Schwarzer, Anne-Katrin, Hutchinson, John M. C., Schlitt, Bettina (2020): Genital morphology differentiates three subspecies of the terrestrial slug Arion ater (Linnæus, 1758) s. l. and reveals a continuum of intermediates with the invasive A. vulgaris Moquin-Tandon, 1855. Folia Malacologica 28 (1): 1-34, DOI: 10.12657/folmal.028.001, URL: http://dx.doi.org/10.12657/folmal.028.001
72141214A544FFA0CE23FBB1A0A9F919.taxon	discussion	To find the appropriate name for the FR morphotype, we sought post- 1758 descriptions of rufus - like slugs from continental Europe. We believe the name having priority is Limax ruber Garsault, 1764, which GARSAULT (1767: 376) described as a red brown slug, larger than Helix pomatia. His illustration (GARSAULT 1764: pl. 644; https: // gdz. sub. uni-goettingen. de / id / PPN 496755056) is recognisably an Arion species on account of the position of the pneumostome. Judging from other illustrations, the pale lateral band in this illustration is merely the artist’s device to indicate the round form. No locality was given, but the neighbourhood of Paris, where Garsault worked (WELTER-SCHULTES et al. 2008) is the most reasonable assumption. This would be compatible with occurrences of fr in that area (ZEMANOVA et al. 2016). However, it would be desirable to designate a neotype to remove all doubt about the correspondence of ruber with the FR morphotype, as is our future intention. The name of the FR morphotype becomes	en	Reise, Heike, Schwarzer, Anne-Katrin, Hutchinson, John M. C., Schlitt, Bettina (2020): Genital morphology differentiates three subspecies of the terrestrial slug Arion ater (Linnæus, 1758) s. l. and reveals a continuum of intermediates with the invasive A. vulgaris Moquin-Tandon, 1855. Folia Malacologica 28 (1): 1-34, DOI: 10.12657/folmal.028.001, URL: http://dx.doi.org/10.12657/folmal.028.001
72141214A544FFA0CCCEFD3EA182FBF9.taxon	discussion	but should	en	Reise, Heike, Schwarzer, Anne-Katrin, Hutchinson, John M. C., Schlitt, Bettina (2020): Genital morphology differentiates three subspecies of the terrestrial slug Arion ater (Linnæus, 1758) s. l. and reveals a continuum of intermediates with the invasive A. vulgaris Moquin-Tandon, 1855. Folia Malacologica 28 (1): 1-34, DOI: 10.12657/folmal.028.001, URL: http://dx.doi.org/10.12657/folmal.028.001
72141214A544FFA0CCCEFD3EA182FBF9.taxon	discussion	be applied to the BR or to the FR morphotype? As detailed by VAN REGTEREN ALTENA (1963), LINNAEUS’ (1758) description of rufus referred to his book on the Swedish fauna (LINNAEUS 1746; but the implied Swedish occurrence must almost certainly have been Arion fuscus: ODHNER 1951, VON PROSCHWITZ 1985), to German material described by ALDROVANDI (1644), and to the work of LISTER (1685), who described both British and French specimens. Because both BR and FR forms occur on the Continent, but FR or fr are almost unknown in Britain (CHEVALLIER 1974, ROWSON et al. 2014 a), greater certainty is achieved by selecting a British specimen as the lectotype. Also this choice follows Recommendation 74 A of the Code (ICZN 1999) in ensuring compatibility with the nomenclature of CHEVALLIER (1972, 1974) and ROWSON et al. (2014 a, b). Hereby we designate as the lectotype of Limax rufus Linnaeus, 1758 a now non-existing specimen amongst those described by LISTER (1685: 7) from “ Amberry ” in Yorkshire. Amberry is Almondbury, south of Huddersfield, which may still be pronounced as Lister wrote it and appears with spellings similar to Lister’s in contemporary documents (SMITH 1961, TAYLOR 1975). The illustration of “ Limax rufus ” (LISTER 1685: fig. 1 on tabula 2), to which LINNAEUS (1758) also refers (he originally indicated “ p. 1 ” but in the 12 th edition — LINNÉ 1767: 1081 — corrected this to “ t. 2. f. 1 ”), is plausibly of an individual from this population, since foreign localities, but not British ones, are consistently included in the captions to others of LISTER’ s (1685) figures, and Amberry is the single British locality for the species mentioned in the main text. In any case, since the illustration does not reveal anatomical characters, it is better to associate the lectotype with the named locality, from which fresh specimens can be collected, than to designate an illustrated specimen of uncertain origin. (Recommendation 74 E of the Code (ICZN 1999) trumps Recommendation 74 B, which applies only “ other things being equal ”.) It is unlikely that any of LISTER’ s (1685) specimens of this species survive. In 1683 he deposited a collection of specimens illustrated in LISTER (1678) in the Ashmolean Museum, and an accompanying letter promised more; so perhaps the specimens described in LISTER (1685), the appendix to LISTER (1678), followed them. Nothing of this collection is known to have survived (MACGREGOR 2001).	en	Reise, Heike, Schwarzer, Anne-Katrin, Hutchinson, John M. C., Schlitt, Bettina (2020): Genital morphology differentiates three subspecies of the terrestrial slug Arion ater (Linnæus, 1758) s. l. and reveals a continuum of intermediates with the invasive A. vulgaris Moquin-Tandon, 1855. Folia Malacologica 28 (1): 1-34, DOI: 10.12657/folmal.028.001, URL: http://dx.doi.org/10.12657/folmal.028.001
72141214A544FFA0CCCEFD3EA182FBF9.taxon	discussion	We associate our BR morphotype with A. ater rufus because in Britain the br haplogroup is widespread (combining information from COI and 16 S sequences) whereas the fr haplogroup is known from only a single locality (ROWSON et al. 2014 a). Furthermore, all reddish specimens of A. ater s. l. from Britain that we have dissected are BR, which agrees with the results of CHEVALLIER (1974). Moreover, we have recently found the BR morphotype occurring commonly in Almondbury, now the type locality. In theory LISTER’ s (1685) red slugs might instead have been hybrids between BR and A. ater ater, or improbably early occurrences of presumably non-native species such as A. vulgaris or A. flagellus. These possibilities could be made irrelevant to the issue of taxonomy with the designation of an appropriate neotype, as is our future intention. Our Arion ater rufus (Linnaeus, 1758)	en	Reise, Heike, Schwarzer, Anne-Katrin, Hutchinson, John M. C., Schlitt, Bettina (2020): Genital morphology differentiates three subspecies of the terrestrial slug Arion ater (Linnæus, 1758) s. l. and reveals a continuum of intermediates with the invasive A. vulgaris Moquin-Tandon, 1855. Folia Malacologica 28 (1): 1-34, DOI: 10.12657/folmal.028.001, URL: http://dx.doi.org/10.12657/folmal.028.001
