Limax redii

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Limax redii
Systematics
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Family : Schnegel (Limacidae)
Subfamily : Limacinae
Genre : Limax
Type : Limax redii
Scientific name
Limax redii
Gerhardt , 1933

Limax redii is a species of nudibranch from the family of snails (Limacidae), which belongs to the land snails (Stylommatophora). It is an endemic species in a small area in the Southern Alps. With a length of up to 85 cm, it has one of the longest “ penes ” of all Limax speciesknown to date. It is not a penis in the strict sense of the word (as is the case with vertebrates, for example), but rather it is the transmitting and receiving organ for the sperm. The species is named after Francesco Redi , an Italian physician and naturalist who first described the extremely unusual copulation of this species (or more likely a closely related species) in 1684.

features

Limax redii is stretched out about 13 to 15 cm long, rarely up to 23 cm. The specimens are cream-colored, brownish-sand-colored to yellowish, occasionally with a slight bluish tint, with individual, irregularly distributed black dots, whereby the coat is usually less densely dotted. Single-colored specimens are also less common. The head and tentacles are gray. The sole of the foot is one color.

In the genital apparatus, the cylindrical penis is up to 85 cm long and strongly twisted. The penis retractor starts near the apical end, which is designed as a blind sac . The longitudinal folds ("combs") inside the penis start at the blind end. In the everted penis, they sit on the outside near the tip of the penis.

Similar species

Limax redii differs from the Black Schnegel ( Limax cinereoniger ), which is "only" about body length in this species, and by its copulation behavior. L. cinereoniger does not produce a tape of slime, L. redii a "slime sail" and the tiger nose ( L. maximus ) a thread of slime up to 40 cm long. In L. cinereoniger and L. maximus, the penes protrude very quickly in seconds, and in L. redii very slowly. In L. cinereoniger and L. maximus the penes are twisted spirally, in L. redii only initially, later they hang down parallel and are attached to one another by mucus. The entire copulation takes about 30 to 45 minutes for L. cinereoniger and L. maximus and up to 19 hours for L. redii .

Geographical distribution and habitat

The distribution area is limited to a small area in the southern Alps (Ticino and Lombardy west of Lake Como). In Switzerland it rises to around 900 m.

The species lives there in mixed deciduous forests with a lot of dead undergrowth on chalky soil. In winter, the animals crawl deep in the earth or between stones. They usually live deep in the leaf litter in summer.

Way of life

Little is known about the nutrition of this species in the biotope . In captivity, the species could be fed with cucumbers, carrots and lettuce without any problems. The mating takes place in the biotope in September and October in damp weather and warm temperatures. It takes about 12 to 19 hours. Ulrich Gerhardt described the pairing in detail, but under laboratory conditions. One animal starts chasing another animal. The persecutor repeatedly licks the tail tip of the persecuted. The movements are slower and more leisurely than with the Black Schnegel. The persecution ends with the persecuted person turning back to the right and forming a circle. This usually takes place at a height of more than one meter above the ground on vertical surfaces, for example walls, walls or trees. Then the front bodies lift off and wrap around themselves. The wrapping becomes increasingly tighter, the front bodies hang down, the tips of the tails up. The tips of the tail are now lifted lengthways halfway from the base; at the same time, a lot of mucus is secreted. This leads to the formation of a so-called "slime gel", two triangular slime surfaces with which the animals are attached to the surface. The penes are not initially everted. Only after the later copulation position has been taken do the penes begin to protrude. This can take over 20 minutes from the formation of the circle to the protuberance. The heads of the animals withdraw more and more under the coat shield, which protrudes downwards like a pointed hood. The following eversion of the penes takes place very slowly; it can take over an hour. The wrapping of the penes only begins when the penes have been everted about 2 cm (around 1 ¼ hours after the front body has been wrapped). During this phase, the so-called “blue zone” also develops in the penes. While the tips of the penes are leg-colored, blue body fluid ( hemolymph ) collects in the area above ; the bases of the penes are again whitish.

The actual mating that now follows can take over 12 hours. The wrapping of the penes is given up again with increasing protuberance (at 3 cm there are three turns). The two penes now hang parallel to each other and are attached to each other with slime except for the tips. In the phase of lengthening the penes, they are pulled in a little at irregular intervals and then lengthened again beyond the previous dimension. The tips move vigorously. If the penes are about 20 cm everted, the wheat-grain-sized sperm packets (also called spermatophores in the literature ) appear at the base of the penes , but usually not at the same time. Now the further lengthening is done quickly and the penes can reach a length of 85 cm in large specimens. The penes are not continuously everted, but an extension is followed by a smaller shortening and an extension beyond the previous dimension, etc. The combs are upright, they protrude from the "blue zone" by about four to five centimeters. The ends of the penis are thickened. The sperm packets now migrate through the penis tubes. Since they do not come out at the same time, a parcel of sperm reaches the tip of the penis first. Ulrich Gerhardt even observed in a copulatory couple that one sperm packet overtook the other, although it later leaked at the base of the penis. The first sperm package now stops about half a centimeter above the tip of the penis and remains in this position. The second sperm package finally also reaches the blue zone and now a kind of pumping activity begins. By shortening the penile tubes, blue liquid is pushed upwards over the spermatophores. During the subsequent elongation, the blue liquid is pushed downwards and the spermatophore advances a little. Eventually the spermatophore and also the blue liquid reach the tip of the penis and also color the combs blue, while the combs and tip of the other penis remain white and the blue zone is well above the tip.

Once the sperm packets have reached the tips with a slight horizontal rotation of the tips, the transfer of the sperm packets begins. If the sperm packet now appears at the tip of the penis, the comb opens into a pocket open at the top, picks up the semen packet, wraps around the partner's penis and attaches the semen packet. The same thing now happens with the other partner's sperm packet. This all happens very quickly in seconds. Then the last 10 cm become entangled and the drawing-in and turning-in begins. The sperm packets are absorbed into the penes. The penes can be drawn in in just a few minutes. The animals stretch their heads under the coat and begin to separate from each other. After about six minutes, the animals have separated from each other, the penes have retracted to within a few centimeters. However, it can then take another half an hour for the penes to be fully withdrawn. The mating ritual with copulation and separation of the animals can last up to 19 hours in total.

Taxonomy

The copulation of Limax redii (or more likely a closely related species) was first documented by Francesco Redi as early as 1684 . He made his observations in Tuscany, an area in which Limax redii does not occur according to current knowledge. The work of Francesco Redi was historically rated in 2012 by Andrea Benocci and Manganelli. Bernhard Peyer and Eduard Kuhn later described copulation again. However, they assumed that it was L. cinereoniger . Only Ulrich Gerhardt recognized the independence of the taxon and named it in honor of Francesco Redi Limax redii . The type material came from Serpiano (Canton Ticino, Switzerland). Manganelli et al. (1995) consider L. redii to be a more recent synonym of Limax punctulatus Sordelli, 1871, but without giving a reason for it. The anatomy and the copulation behavior of this species are not yet known (from the Typicus locus ). A population from Bulgaria was also established for this species. Their copulation has been documented by Ivaylo Dedov and differs fundamentally with the copulation behavior of L. redii . In the everted state, the penis is almost body-length and twisted in a spiral. The partners are attached to the base through the tips of their tails. This is comparable to the copulation behavior of the black snail ( Limax cinereoniger ). At least this Bulgarian population is definitely not identical to L. redii .

literature

Web links

Individual evidence

  1. ↑ A presumably new Limax species from the Montagnola Senese (northwest and west of Siena , northern Italy) has an even longer penis of 92.5 cm (Nitz, Barbara, Gerhard Falkner & Gerhard Haszprunar 2010: Inferring Multiple Corsican Limax (Pulmonata: Limacidae ) Radiations: A Combined Approach Using Morphology and Molecules. In: Glaubrecht, Matthias (Ed.): Evolution in Action-Case studies in Adaptive Radiation, Speciation and the Origin of Biodiversity, pp. 405-435, Springer Verlag, p. 414 ).
  2. ↑ a b Gerhardt (1933: p. 425 to p. 442)
  3. ↑ Redi, Francesco: Osservazioni intorno agli animali viventi che si trovono nelli animali viventi. Florence 1684 ( books.google.de ).
  4. ↑ Andrea Benocci, Giuseppe Manganelli: Early research on anatomy and mating of land slugs and snails: Francesco Redi's (1684) Osservazioni. In: Archives of natural history. Volume 39, No. 2, October 2012, pp. 270-280, doi: 10.3366 / anh.2012.0094 .
  5. ^ Bernhard Peyer, Eduard Kuhn: The copulation yon Limax cinereoniger Wolf. In: Quarterly publication of the Natural Research Society in Zurich. 73. pp. 485-488, Zurich 1928.
  6. ^ Giuseppe Manganelli, Marco Bodon, Leonardo Favilli, Folco Giusti: Fascicolo 16. Gastropoda Pulmonata. In: A. Minelli, S. Ruffo, S. La Posta: Checklist delle specie della fauna italiana. Calderini, Bologna 1995, pp. 1-60, here p. 28.
  7. ↑ A. Irikov, I. Mollov: Terrestrial gastropods (Mollusca: Gastropoda) of the western Rhodopes (Bulgaria). In: P. Beron: Biodiversity of Bulgaria. 3. Biodiversity of western Rhodopes (Bulgaria and Greece). 2006, pp. 753-832, ISBN 954-642-279-7 , ISBN 954-8828-04-9 .
  8. ↑ Ivaylo Dedov: Check-list of the Bulgarian terrestrial snails (Mollusca, Gastropoda). ( Page no longer available , search in web archives: idedov.wordpress.com )@1@ 2Template: Dead Link / idedov.wordpress.com