Land Snails of Cape Breton - Integrative Science

Land Snails of Cape Breton - Integrative Science

Land Snails of Cape Breton BACKGROUND This key was produced from 1995 – present. It was written by Ryan Luedy and Jean MacMillan, two undergraduate b...

3MB Sizes 0 Downloads 8 Views

Recommend Documents

Land Snails
Oct 1, 2005 - GENERAL INFORMATION: The Hawaiian native land snail fauna is probably the most diverse in the world per un

Von Halifax nach Cape Breton Island - Canada.travel
Laut einer Legende der Mi'kmaq soll der Gott Glooscap angeblich die Bay of Fundy geformt haben, indem er Erdstücke ins W

THE PARADOX OF THE PERIPHERY Evolution of the Cape Breton
Chapter Seven Performing the Repertory - Contexts and Practices................ 224. 7.1 ..... the people were evicted f

land snails - UAE Interact
The UAE is home to seven native species of land snails representing five pulmonate families, as well as at least six int

Giant African land snails - rspca
Prior knowledge and preparation. Before acquiring a giant African land snail, it is crucial that any potential keeper fi

KE'ILAKNUTMA'TINEJ - Integrative Science
Apr 27, 2007 - He is a member of the National Working Group of Crisis Negotiators ... During 2005/06, at the request of

New Zealand land snails - DoC
New Zealand land snails. Powelliphanta. These meat-eating giants of the forest floor are true biological oddities, posse

land snails sicily - Biodiversity Journal
New and little known land snails from Sicily (Mollusca. Gastropoda). Fabio Liberto1, Salvatore Giglio2, Maria Stella Col

Land Snails of Leicestershire and Rutland - NatureSpot
There are 50 known species of land snail found in Leicestershire and Rutland (VC55) ... All our land snails are in the c

Land Snails of Cape Breton

BACKGROUND This key was produced from 1995 – present. It was written by Ryan Luedy and Jean MacMillan, two undergraduate biology students. All illustrations, unless otherwise noted, were created by Basma Kavanagh. Financial support was provided by Cape Breton University and the Natural Sciences and Engineering Research Council. Cape Breton Island makes up roughly onefourth of the Province of Nova Scotia. The Island is separated from the mainland by the Straight of Canso. Although a causeway has been constructed across the straight in the 1950’s, the two land masses have been separated from each other long enough to allow differences in fauna, including terrestrial mulluscs, to develop. Cape Breton contains species not found on the mainland and vice versa. There are a number of explanations for this. One reason is that species radiating from Western Canada were halted by the straight.

©msit 2005

Another reason is that extinctions may have occurred on Cape Breton Island but not on the mainland or vice versa. As well, species could have been introduced to Cape Breton Island via old settlements, like Louisburg, and not introduced to the mainland. Again, the opposite may have happened, species may have been introduced to the mainland and not Cape Breton. Although the number of mollusc species found on Cape Breton Island and in the rest of Nova Scotia is small when compared to other places in the world, there are significant numbers of species present to warrant study of them. That is why this key to the Land Snails and Slugs of Cape Breton has been constructed, to encourage people to study these unique creatures and become aware of their presence.

Land Snails of Cape Breton

INTRODUCTION Land snails are soft unsegmented animals that belong to the phylum Mollusca. As indicated in figure 1, land snails have a ventral foot, four tentacles: an upper pair that have eyes and a lower pair that lack eyes, and a mantle that contains the animal’s internal organs, and is usually enclosed in a calcareous shell. These animals are hermaphroditic, meaning there are no males or females; every individual has both male and female reproductive organs. However, two snails or two slugs of the same species must meet in order to lay eggs, they cannot self-fertilize. For these animals, this insures that when two animals meet, they can reproduce; they do not have to look for a mate of the proper sex. Land snails and slugs can be found almost anywhere, but especially in those areas that offer shelter, moisture, food,

©msit 2005

and for snails a source of calcium, usually in the form of limestone. Land snails can be found most easily on foggy / rainy days in the spring and summer. They tend to be on low green plants, tree trunk bottoms,and in the first few centimeters of soil. Therefore, snails can be collected in a couple of ways.

Land Snails of Cape Breton

INTRODUCTION One way is to pick them up as you closely examine the ground vegetation on a damp/rainy day. Another way is to shake soil/leaf litter samples on a mesh screen (about .5 cm holes), collect the material that passes through, and then look through it under a microscope. This technique works very well for small species. Some snail shells can be smaller than 1mm, and nearly impossible to collect any other way. After snails have been collected, they can be kept live or can be preserved. To keep them alive, place them in a cool, moist place with some food. Be sure to contain them in a sealed container that allows air to enter. Fresh lettuce and carrot slices seem to keep them happy. Some wet woodchips, sand, or soil should be placed in the bottom of their home, to keep them moist. To preserve snails, one of two things can be done. They can be left to dry out. Small ones can be dried as is. After a period of

©msit 2005

time, the dried body can be removed from the shell or it can be left alone. For larger species, it is best to remove as much of the body as possible with forceps or a bent pin before drying. The second way to preserve snails, and the only way to preserve slugs, is to store them in vials of preservative.

Land Snails of Cape Breton

IDENTIFICATION In order to identify snails and slugs you must first become familiar with some important features of the animals. The following figures will illustrate the important features used in identification of land snails and slugs.

General external features of typical snail

©msit 2005

Method of counting whorls when snail is viewed from above

Land Snails of Cape Breton

IDENTIFICATION In order to identify snails and slugs you must first become familiar with some important features of the animals. The following figures will illustrate the important features used in identification of land snails and slugs.

A = Diameter/Width B = Height/Length

Method of Measuring a Shell

Shell Terminology

Method of measuring shell

Shell Terminology

Shell Textures ©msit 2005

Shell Showing Indented Radiating Lines

Land Snails of Cape Breton

IDENTIFICATION On order to identify snails and slugs you must first become familiar with some important features of the animals. The following figures will illustrate the important features used in identification of land snails and slugs.

Shell Lip Types A = reflected lip B = straight lip

Types of Shells (viewed from below)

©msit 2005

Land Snails of Cape Breton

IDENTIFICATION On order to identify snails and slugs you must first become familiar with some important features of the animals. The following figures will illustrate the important features used in identification of land snails and slugs.

Shell Periphery Types

©msit 2005

Shell Shapes

Shell Shapes Shell Periphery Types

External features of a typical land slug

Land Snails of Cape Breton

GLOSSARY Angular Periphery: See periphery types. Apex: The top or first whorl on the shell that is farthest away from the aperture. Body Whorl: the last outermost whorl of a snail shell. Breathing pore: An opening in the mantle edge that serves for air passage into the lung cavity. Columella: the edge on the inner side of the aperture. Foot: Located towards the back of the snail on the ventral surface. The foot is used mostly for locomotion as well as digging and grasping food.

©msit 2005

Growth Lines: A thin line on the surface of the shell indicating a period of rest in the growth cycle. Hirsute: covered with small hairlike projections. Imperforate: Lacking an umbilicus on the underside of shell. Keel: A sharp ridge down the dorsal surface of a slug, usually restricted to the posterior end. Lamella: A fold or raised tooth inside the aperture. Lip: the edge of the shell on the outside of the aperture.

Land Snails of Cape Breton

GLOSSARY Mantle: a soft outer covering of the visceral mass Radiating Indented Lines: Evenly of the mollusc; in snails it is under the shell. spaced, impressed lines of the shell of a snail that are perpendicular to the whorls. Moderately Unbilicate: see umbilicus Reproductive Pore: in snails the Narrowly Umbilicate: see umbilicus reproductive pore is located in the head region. In slugs the reproductive pore is Nuclear Whorl: The first two whorls of the snail located beside or below the breathing pore. shell. Reflected Lip: The shell is turned away Ovate: Oval shaped. from the snail at its end, the lip. Pedal Groove: a longitudinal groove in the side of the foot of a snail or slug that marks the boundary of foot sole and side. Periphery: the outer edge of the body whorl. Pigment Band: a longitudinal band or strip of colour found on the sides or dorsal surface of slugs.

©msit 2005

Ribs: Transverse projections on the outside of the snail shell, evenly spaced, and provided the shell is larger than a few millemetres, can be seen with the naked eye. Round Periphery: See periphery types.

Land Snails of Cape Breton

GLOSSARY Spiral Lirae: raised lines or ridges on the surface of the shell that run in the same direction as the whorls (spirally). Striae: faint lines within the structure on a snail’s shell. Subangular Periphery: See periphery types. Suture: the junction between two successive whorls.

©msit 2005

Umbilicus: a hole or opening in the center of the underside of the shell. The terms widely umbilicate, narrowly umbilicate and moderately umbilicate refer to the relative width of the umbilicus compared to the diameter of the shell. Those that are widely umbilicate have and umbilicus that is greater than 1/2 shell diameter. Narrowly umbilicate shells have an umbilicus that is less then 1/3 and moderately umbilicate shells fall in between. Widely Umbilicate: See umbilicus

Land Snails of Cape Breton

KEY

1A • External Shell Present

GO TO: 2A - 2B

©msit 2005

1B • External Shell Absent

GO TO: 7A - 7B

Land Snails of Cape Breton

KEY

2A • Shell distinctly wider than high

GO TO: 12A - 12B

©msit 2005

2B • Shell higher than wide, or as wide as it is high

GO TO: 3A - 3B

Land Snails of Cape Breton

KEY 3A • Shell as high as wide

GO TO: 21A - 21B

©msit 2005

3B • Shell distinctly higher than wide

GO TO: 4A - 4B

Land Snails of Cape Breton

KEY 4A • Aperature length more than half the shell length

GO TO: SPECIES FIG. #16

©msit 2005

4B • Aperature length less than one half the shell length

GO TO: 5A - 5B

Land Snails of Cape Breton

KEY 5A • Aperature without lamellae

GO TO: 6A - 6B

©msit 2005

5B • Aperature with lamellae

GO TO: SPECIES FIG. #17

Land Snails of Cape Breton

KEY 6A • Shell is spindle shaped, very glossy, tan and 5–7.5 mm in height

GO TO: SPECIES FIG. #18

©msit 2005

6B • Shell cylindrical shaped, tan with white streaks, and is 5–7.5 mm in height

GO TO: SPECIES FIG. #19

Land Snails of Cape Breton

KEY 7A • Mantle covers nearly entire animal

GO TO: 8A - 8B

©msit 2005

7B • Mantle covers only an anterior portion of the animal

GO TO: 9A - 9B

Land Snails of Cape Breton

KEY 8A • Slug is small, 15mm or less

GO TO: SPECIES FIG. #21

©msit 2005

8B • Slug is large, 50mm or greater

GO TO: SPECIES FIG. #20

Land Snails of Cape Breton

KEY 9A • Breathing pore located in anterior portion of mantle, back not keeled and posterior end of body rounded when viewed from above

GO TO: 23A - 23B

©msit 2005

9B • Breathing pore located in posterior portion of mantle, back keeled at posterior end of body when is pointed when viewed from above

GO TO: 10A - 10B

Land Snails of Cape Breton

KEY 10A • Slug 70mm or greater in length when extended

GO TO: SPECIES FIG. #22

©msit 2005

10B • Slug 50 mm or less in length when extended

GO TO: 11A - 11B

Land Snails of Cape Breton

KEY 11A • Slug 35-50mm in length, mantle situated near head, animal exudes milky slime when irritated

GO TO: SPECIES FIG. #23

©msit 2005

11B • Slug 15-30mm in length, mantle situated slightly back from head, animal exudes watery slime when irritated

GO TO: SPECIES FIG. #24

Land Snails of Cape Breton

KEY 12A • Shell is 15mm or greater in width

GO TO: SPECIES FIG. #25

©msit 2005

12B • Shell is less than 15mm in width

GO TO: 13A - 13B

Land Snails of Cape Breton

KEY 13A • Shell with raised spiral lirae

GO TO: SPECIES FIG. #26

©msit 2005

13B • Shell without raised spiral lirae

GO TO: 14A - 14B

Land Snails of Cape Breton

KEY 14A • Shell with ribs and without a reflected lip

GO TO: SPECIES FIG. #27

©msit 2005

14B • Shell without ribs

GO TO: 15A - 15B

Land Snails of Cape Breton

KEY 15A • Shell without a reflected lip

15B • Shell with a reflected lip

GO TO: 16A - 16B

GO TO: SPECIES FIG. #28

©msit 2005

Land Snails of Cape Breton

KEY 16A • Shell white in colour

GO TO: SPECIES FIG. #29

©msit 2005

16B • Shell not white in colour

GO TO: 17A - 17B

Land Snails of Cape Breton

KEY 17A • Snail without pedal grooves and 7–9mm in width

GO TO: SPECIES FIG. #30

©msit 2005

17B • Snail with pedal groove and less than 6mm in width

GO TO: 18A - 18B

Land Snails of Cape Breton

KEY 18A • Snail with radiating indented lines

GO TO: SPECIES FIG. #31

©msit 2005

18B • Snail without radiating indented lines

GO TO: 19A - 19B

Land Snails of Cape Breton

KEY 19A • Shell from 4.5–5.6mm in diamter, faint yellow or brownish

GO TO: 20A - 20B

©msit 2005

19B • Shell 2.2mm in diameter, nearly colourless

GO TO: SPECIES FIG. #32

Land Snails of Cape Breton

KEY 20A • Shell with whorls slowly increasing in width, aperature small

GO TO: SPECIES FIG. #33

©msit 2005

20B • Shell with whorls rapidly increasing in width, aperature relatively large

GO TO: SPECIES FIG. #34

Land Snails of Cape Breton

KEY 21A • Shell with ribs

GO TO: 22A - 22B

©msit 2005

21B • Shell without ribs

GO TO: SPECIES FIG. #35

Land Snails of Cape Breton

KEY 22A • Shell with reflected lip and lamellae in aperature

GO TO: SPECIES FIG. #36

©msit 2005

22B • Shell without reflected lip and without lamellae in aperature

GO TO: SPECIES FIG. #37

Land Snails of Cape Breton

KEY 23A • Breathing pore located below right mantle pigment band

GO TO: SPECIES FIG. #38

©msit 2005

23B • Breathing pore located in right mantle pigment band

GO TO: 24A - 24B

Land Snails of Cape Breton

KEY 24A • Slug 20-40mm in length, sole of foot yellow and animal almost black in colour

GO TO: SPECIES FIG. #39

©msit 2005

24B • Slug 60-80mm in length, sole of foot pale yellow and animal yellowish brown

GO TO: SPECIES FIG. #40

Land Snails of Cape Breton

KEY 16 • Succinea spp. Length: 7.2mm; (N=4) (x=6.4mm) Shell with 2.5 whorls, very thin, pale yellow, aperture ovate, lip sharp. Note: species identification is not well known and therefore only genus is given.

©msit 2005

Land Snails of Cape Breton

KEY 17 • Vertigo pygmaea (Draparaund) Length: 2.0mm; (N=2) (x=2.0mm) Shell with 5 whorls, chestnut-brown, lip reflected, containing lamellae.

©msit 2005

Land Snails of Cape Breton

KEY 18 • Cochlicopa lubrica (Müller) Length: 5.0 -5.6mm; (N=6) (x=5.1mm) Shell with about 5–5.5 whorls, light tan, very glossy, lip not reflected by thickened within, columell slightly sinuate.

©msit 2005

Land Snails of Cape Breton

KEY 19 • Columella edentula (Draparnaud) Length: 1.75–2.5mm; (N=4) (x=1.8mm) Shell with about 5.5–6.5 whorls, cylindrical, perforate, cinnamon, thin, smooth but with irregular growth lines. Shell length given is for adults, but smaller juveniles are more commonly found.

©msit 2005

Land Snails of Cape Breton

KEY 20 • Philomycus fluxuolaris (Rafinesque) Length: 50mm; (N=4) (x=45mm) Slug is dark brown with lighter flecks, faint darker bands down sides, foot fringe has reddish tinge, mantle covers nearly entire body.

©msit 2005

Land Snails of Cape Breton

KEY 21• Pallifera dorsalis (Binney) Length: 6.5 -15mm; (N=2) (x=unknown) Slug is usually gray or bluish-gray with darker coloured sections, foot sole white, may have a dark line along dorsal surface of mantle.

©msit 2005

Land Snails of Cape Breton

KEY 22• Limax maximus (Linné) Length: 82-120mm; (N=7) (x=118mm) Slug is light to dark brown, black spots on both mantle and body, body not banded, mucus colourless.

©msit 2005

Land Snails of Cape Breton

KEY 23• Deroceras reticulatum (Müller) Length: 16-28mm; (N=14) (x=24.3) Slug is light coloured, darker inconspicuous markings on entire body, commonly called the Grey Garden Slug.

©msit 2005

Land Snails of Cape Breton

KEY 24• Deroceras laeve (Müller) Length extended: 9-24mm; (N=4) (x=15.2) Slug usually solid coloured, dark brown to black, similar to Deroceras reticulatum but smaller and more uniform in colour.

©msit 2005

Land Snails of Cape Breton

KEY 25 • Cepaea hortensis (Müller) Diameter: 13.7–19.5 mm; (N=25) (x=16.9mm) Shell with 4–4.5 whorls, banana yellow, may have 1–5 brown bands on each whorl, may be translucent or opaque, aperture lip reflected and white when viewed from inside, commonly called the white-lipped garden snail.

©msit 2005

Land Snails of Cape Breton

KEY 26 • Helicodiscus parallelus (Say) Diameter: 3.2–3.5mm; (N=1) (x=3.2mm) Shell with 4–4.5 whorls, pale green, spiral lirae poorly developed on first one or two whorls.

©msit 2005

Land Snails of Cape Breton

KEY 27 • Discus catskillensis (Pilsbry) Diameter: 3.7–4.2mm; (N=16) (x=4.1mm) Shell with 4 whorls, pale brown, angular periphery, wide umbilicus.

©msit 2005

Land Snails of Cape Breton

KEY 28 • Vallonia pulchella (Müller) Length: 2.2mm; (N=4) (x=2.1mm) Shell with about 3 whorls, whitish, faint growth lines, moderately umbilicate.

©msit 2005

Land Snails of Cape Breton

KEY 29 • Hawaiia minuscula (A. Binney) Length: 2–2.8mm; (N=1) (x=2.1mm) Shell with about 3.5–4.5 whorls, pale whitish, distinct growth wrinckles, umbilicus about 1/3 shell diameter.

©msit 2005

Land Snails of Cape Breton

KEY 30 • Trichia (Trichia) hispida (Linne) Length: 6.1–8.5mm; (N=21) (x=7.3mm) Shell with 5–6 whorls, pale cinnamon-brown, rounded whorls, hirsute shell condition remaining in adults.

©msit 2005

Land Snails of Cape Breton

KEY 31 • Glyphyalinia indentata (Say) Diameter: 4.7–7.1mm; (N=7) (x=3.9mm) Shell with 4.5–5 whorls, tan, translucent, radiating indented lines evenly spaced, faint growth lines and stiae also visible.

©msit 2005

Land Snails of Cape Breton

KEY 32 • Nesovitrea binneyana (Say) Length: 3.5 -5.3mm; (N=3) (x=3.1mm) Shell with 3.5–4 whorls, almost colourless, faint green, very similar to Nesovitrea electina.

©msit 2005

Land Snails of Cape Breton

KEY 33 • Zonitoides arboreus (Say) Diameter: 5-6mm; (N=34) (x=3.8mm) Shell with 4.5 -5 whorls, brownish in colour, faint spiral striae.

©msit 2005

Land Snails of Cape Breton

KEY 34 • Nesovitrea electina (Gould) Diameter: 4.6 -5.2mm; (N=4) (x=4.8mm) Shell with 3.5 whorls, pale green to brown, moderately umbilicate.

©msit 2005

Land Snails of Cape Breton

KEY 35 • Euconulus fulvus (Müller) Diameter: 2.6mm; (N=1) (x=2.6mm) Shell with 4.5–6 whorls, tan, conical spire, lip thin, periphery rounded or sub angular.

©msit 2005

Land Snails of Cape Breton

KEY 36 • Strobilops labryinthica (Say) Diameter: 2.3 -2.5mm; (N=4) (x=2.2mm) Shell with 5.5 whorls, light brown, ribs absent on the inderside of shell, spire conically shaped, narrowly perforate.

©msit 2005

Land Snails of Cape Breton

KEY 37 • Zoögenetes harpa (Say) Diameter: 1.5 -2.5mm; (N=9) (x=2.1mm) Shell with 4 whorls, olive-brown, last two whorls sculptured with ribs, first few smooth, lip thin, not reflected.

©msit 2005

Land Snails of Cape Breton

KEY 38• Arion fasciatus (Nilsson) Length extended: 20-46mm; (N=16) (x=34.3) Slug pale gray to black with a porcelain white foot, muscus clear. Reproductive pore located in front of breathing pore, breathing pore below right pigment band. Sides of body have dark longitudinal bands.

©msit 2005

Land Snails of Cape Breton

KEY 39• Arion hortensis (Ferussac) Length extended: 20-40mm; (N=3) (x=30) Slug dark gray to black, posterior end rounded when viewed from above, right mantle pigment band thick, dark and covering breathing pore.

©msit 2005

Land Snails of Cape Breton

KEY 40• Arion subfuscus (Draparnaud) Length: 60-80mm; (N=11) (x=64) Slug yellowish, mantle pigment band faint, foot pale yellow, breathing pore within pigment band. When killed in salt water or deoxygenated water, it balloons out a reproductive pore, located just below the breathing pore on the right side.

©msit 2005