Arion rufus (Linnaeus, 1758) is a large species of slug. It has an interesting defensive behiour: when irritated it can contract to hemispehrical shape.

Some authors consider Arion rufus as a subspecies of Arion ater (Linnaeus, 1758) or as the same species as Arion ater. Arion ater has the same defensive behaviour. Other Arion species can contact their body a little, but they can not contract their body so much. If you are unsure in determination, you can distinguish Arion rufus from Arion vulgaris (Moquin–Tandon, 1855) according to this defensive behaviour.

References:

(in Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. 2010: Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]. – Malacologica Bohemoslovaca, Suppl. 1: 1-37.

Taylor, J. W. (1907). Monograph of the land and freshwater Mollusca of the British Isles. Testacellidae. Limacidae. Arionidae. pt 8–14. Leeds: Taylor brothers. page 168, plate XVIII.

Ampullariidae (apple snails) is a family of freshwater snails. Members of this family are the largest extant freshwater snails.

When searching for gastropods in tropical collection conservatories of Flora Olomouc I have found also these four large shells of apple snails. They are used as hanging flower pots for tropical plants.

References:

Ghesquiere S. 2012: http://www.applesnail.net/ accessed 25 May 2012

 

Planorbarius corneus (Linnaeus, 1758) is a freshwater snail from the family Planorbidae. All Planorbidae have hemoglobin in its respiratory system - in its blood. It is the same respiratory protein that transport oxygen in human's blood. Albino specimen are quite popular in aquaria, but albinos occur in nature sometimes too. When a planorbid snail is an albino snail, then the color of its hemoglobin is clearly visible and the whole snail is in bright red color.

Photo of albino Planorbarius corneus on human hand:

References:

Baker F. C. 1945: The molluscan family Planorbidae. The University of Illinois Press, Urbana. page 13.

Helisoma anceps, synonym: Planorbella anceps, is a freshwater snail from family Planorbidae. It is native to North America. It is sometimes kept in aquaria in Europe.

Planorbidae are breathing free air and their breathing pore is called pneumostome (it is the same as in land snails). The pneumostome is on the right side of the body, but it is close to the median line (= to the center).

The very large pneumostome is visible on this photo of juvenile Helisoma anceps:

Additionally Planorbidae have another breathing organ, that is used for breathing underwater. It is called pseudobranch and it is placed on the left side of the body. It evolved by extending of the anal region and therefore anus is always close to the pseudobranch. The pad-like pseudobranch of an adult Helisoma anceps is about 2 mm wide and 1 mm high. You can see the pseudobranch easily, if you will watch to the left side of your planorbid snails crawling in the water.

The following two photos shows the extended pseudobranch of the same specimen of juvenile Helisoma anceps:

References:

Baker F. C. 1945: The molluscan family Planorbidae. The University of Illinois Press, Urbana. page 3 and page 126. Plate 23, figure 4.

There are 8 species of Deroceras slugs in the Czech Republic (all of them has been recorded in Slovakia too, but the presence of Deroceras invadens has been confirmed in greenhouses only in Slovakia). Note, that Deroceras invadens was formally redescribed in 2011:

Deroceras agreste (Linné, 1758)
Deroceras laeve (O. F. Müller, 1774)
Deroceras invadens Reise, Hutchinson, Schunack & Schlitt, 2011 - [This species was formerly considered as Deroceras panormitanum (Lessona & Pollonera, 1882) in the Central Europe.]
Deroceras praecox Wiktor, 1966
Deroceras reticulatum (O. F. Müller, 1774)
Deroceras rodnae s. lat. Grossu et Lupu, 1965
Deroceras sturanyi (Simroth, 1894)
Deroceras turcicum (Simroth, 1894)

According to the Hutchinson & Reise (2009) the Deroceras rodnae s. lat. has been splitted to the western population: Deroceras juranum Wüthrich, 1993; and to the eastern population: Deroceras rodnae sensu stricto Grossu et Lupu, 1965. The population in Veľká Fatra mountains in Slovakia previously named Deroceras fatrense Mácha, 1981 could be named Deroceras rodnae fatrense Mácha, 1981. That would count as 9 species of Deroceras in the Czech Republic.

Unfortunatelly the only 100% sure identification of these species can be done with the dissection. I will try to summarize to what level such photos of Deroceras can identified, when they were neither collected nor dissected. I have sorted them to groups for this my purpose.

GROUP 1)
Deroceras with one dark color include:
Deroceras laeve + Deroceras invadens + Deroceras sturanyi
But when the slug is dark brown, it is probably Deroceras laeve, especially when they occur in very wet habitats near water.

According to size:
Deroceras laeve - 30 mm
Deroceras invadens - 20-35 (40) mm
Deroceras sturanyi - 35 mm

GROUP 2)
Deroceras with one light brown color:
Deroceras invadens + Deroceras sturanyi

GROUP 3)
Light color with some dark spots:
Deroceras praecox + Deroceras reticulatum + Deroceras rodnae + Deroceras turcicum

Deroceras praecox - 45 mm
Deroceras reticulatum - 60 mm
Deroceras rodnae - 45 mm
Deroceras turcicum - 45 mm

It seems that the only one to be properly identified according to the photo could be Deroceras reticulatum, if it will have typical spots and if it will live on cultivated areas.

GROUP 4)
Deroceras agreste - 40 mm
creamy white
I need to improve my own experience if it is or isn't possible to identify it according to a photo only.

GROUP 5)
violet Deroceras slugs:
Deroceras rodnae s. lat. + Deroceras turcicum

Some of my photos of undissected slugs. All of them are from various localities in Moravia, the Czech Republic:

It is from group 3), it has typical reticulate pattern and it lives on synantrophic locality: on the cargo train station in Olomouc. I think, that it must be Deroceras reticulatum.

 

It is from group 1), although it looks like Deroceras leave, its locality is not wet. The locality is more dry than wet. It is in Olomouc city. It is one of these three species (Deroceras laeve + Deroceras invadens + Deroceras sturanyi), but I do not know which one.

 

Another Deroceras from group 3). Locality: near Pateřín village, between fields, close to the creek.

 

Some Deroceras from group 2). Locality: near Pateřín village, between fields, close to the creek. It is either Deroceras invadens or Deroceras sturanyi.

References:

(in Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. 2010: Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]. – Malacologica Bohemoslovaca, Suppl. 1: 1–37.

Hutchinson J.M.C. & Reise H. 2009: Mating behaviour clarifies the taxonomy of slug species defined by genital anatomy: the Deroceras rodnae complex in the Sächsische Schweiz and elsewhere. – Mollusca 27(2): 183–200.

Reise H., Hutchinson J.M.C., Schunack S. & Schlitt B. 2011: Deroceras panormitanum and congeners from Malta and Sicily, with a redescription of the widespread pest slug as Deroceras invadens n. sp.. – Folia Malacologica 19(4): 201–233. Download from official page requires free registration. (PDF copy on authors website.)

Videos to the the Reise H. et al. (2011) article.

Slugs (Deroceras reticulatum) know what is good for them. Broccoli is full of nutrients and vitamins.

I have taken few photos while a juvenile land snail Trochulus hispidus has been crawling through a very small water pool. Land snails are vulnerable to hyperhydration. But it has spent only about two minutes in the water. Maybe it did not affect its regulation of water much. Hydration is much less known in gastropods than dehydration. Maybe it did it for contact rehydration ("drinking" though the body wall) on that sunny summer day or maybe it has just overcome the pool because it just wanted to go that way. Nobody knows.

I wish you happy and successful new year 2012. I wish you to overcome all difficulties and much more understanding from others.

References:
Barker G. M. (ed.) (2001) The biology of terrestrial molluscs. pages 159-163 and 467-468.

Xerolenta obvia is a hygromiid land snail. As its distribution area is referred Pontic region, but it occurs from Asia Minor to the Baltic Sea and to eastern France.

It lives in open dry grassy habitats. It is xerophilic (drought-resistant) and thermophilic species (lives in relatively high temperatures). This species hibernates in winter and it aestivates during summer for few months.

Aestivating Xerolenta obvia:

A group of aestivating Xerolenta obvia:

Epiphragm of Xerolenta obvia:

It is a hermaphrodite land snail. It means, that one snail specimen has both sexes. Snails tranfer its sperm during mating. Later cross-fertilization occur. After some time later it lays separated 7-95 uncalcified eggs in a single clutch.

They reach sexual maturity in one year or later. For example in one area in Greece they reach maturity in 8 months after egg was layed (7 months after hatching), but they die after egg laying in the age about 1 year. In another area of Greece they reach sexual maturity in 1.5 years after egg was layed (= 18 months) and they have lived 2 years. Other source refer to longevity 2-3 years.

In Mediterranean they are mating and egg laying in autumn only. In Central Europe they are mating and egg laying from late spring to to early summer. It is mating in October (in Greece) after the aestivation in only few days.

I have found photos of mating of this species neither in the literature nor on the internet. I have taken 5 snails from the locality shown above to home at 3rd August 2011 and the later day I have recored the mating of them. Photos are in chronological order, but they are showing the same position all the time:

4th August 2011 06:25

6:29
6:32
Video of mating of Xerolenta obvia (30 seconds at 06:32):

06:39

06:40
Video of the last six minutes of mating:

References:

Irikov A. & Mollov I. (2006). Terrestrial gastropods (Mollusca: Gastropoda) of the western Rhodopes (Bulgaria). pp. 753-832. In: Beron P.: Biodiversity of Bulgaria. 3. Biodiversity of western Rhodopes (Bulgaria and Greece) I.

Falkner G., Obrdlík P., Castella E. & Speight M. C. D. (2001). Shelled Gastropoda of Western Europe. München: Friedrich-Held-Gesellschaft, 267 pp.

Lazaridou M. & Chatziioannou M. (2005). Differences in the life histories of Xerolenta obvia (Menke, 1828) (Hygromiidae) in a coastal and a mountainous area of northern Greece. Journal of Molluscan Studies 71(3): 247-252. doi:10.1093/mollus/eyi032 abstract

(in Slovak) Lisický M. J. (1991). Mollusca Slovenska [The Slovak molluscs]. VEDA vydavateľstvo Slovenskej akadémie vied, Bratislava, 344 pp.

"Species summary for Xerolenta obvia". AnimalBase, last modified 22 March 2011, accessed 5 December 2011.

Arion vulgaris is an important pest in agriculture and it is quite a big slug. It can reach up to 12 cm. It is widely distributed through the Europe. I think, it could be more widely used as a model organism at least in education about basal anatomy of slugs. Despite that, I found no many photos of its anatomy. It is probably because of this species is not usually necessary to be dissected for identification. When some anatomy photos are available, then they are depicting only a part of the reproductive system dissected from the body of the slug and/or they are black-and-white only.

I have briefly dissected the slug: I have removed the body wall (with ovotestis (=glandula hemaphroditica) and with a part of hepatopancreas also accidentally removed) and I have kept the head undissected in detail. This specimen comes from Olomouc, the Czech Republic and I have collected and dissected it on the 11th August 2011.

There are visible the following structures of the reproductive system:

atrium. Atrium is short in comparison of Arion rufus.

epiphallus

bursa copulatrix

oviductus. There should be a ligula within the oviductus that is an identification character of this species, but the ligula is not visible on the photo here, because I did not cut the wall of oviductus.

spermoviductus

glandula albuminalis

ductus hermaphroditicus (white thin meandering like tube)

glandula hemaphroditica and hepatopancreas. Part of hepatopancreas and probably the whole glandula hemaphroditica is accidentally removed from this dissected slug.

There is also visible tube like digestive system and glandulae mucosae:

oesophagus comes from the frontal part and is contected to the hepatopancreas

intestine comes from hepatancreas back to frontal part and it ends with anus, that is not visible here.

References and further reading:

(in Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. 2010: Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]. – Malacologica Bohemoslovaca, Suppl. 1: 1–37.

(in Russian) ГУРАЛЬ-СВЕРЛОВА Н. В. & ГУРАЛЬ Р. И. [Gural-Sverlova N. V. & Gural R. I.] 2011: Морфологические, анатомические и поведенческие особенности слизней из комплекса Arion lusitanicus (Arionidae) на западе Украины. [Morphological, anatomical and behavioural peculiarities of the slugs from the Arion lusitanicus complex in Western Ukraine]. – Ruthenica. 21(2): 97-111.

(in Polish) Riedel A. & Wiktor A. 1974: Arionacea. Ślimaki krążałkowate i ślinikowate: Gastropoda, Stylommatophora. Fauna Polski 2, Warszawa. 141 pp.

Boettgerilla pallens is actively moving through the soil. Juveniles are very agile and the pattern of its moves seems to be nearly incredible sometimes.