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Superfamily Rhytidoidea
Rhytida arnula,photo:Andrew Spurneon
Family Rhytididae

The snails in this family have small to large shells which are low spired.The shells are thin and fragile and often have close-set,axial riblets.The color is generally yellowish to greenish brown. Snails of the Rhytididae family can be found in the Seychelles,Australasia,and South-Africa.They are predators,feeding themselves with other snails,slugs,earthworms and any other invertebrate animal which happens to have the bad luck of crossing their path. They are well equipped with a radula that contains sharp teeth,also,in the genus Natalina,they have a pair of palps,somewhat resembling a moustache. Its highly likely these contain sensory cells which help to track a prey by following its trail. Smaller snails,smaller than 1 cm in shelldiameter,can be devoured in one bite,while the larger snails are eaten piece by piece.After the body has been consumed the snail will wrap the end of the foot around the empty shell and carry this around for awhile.The shell will slowly disolve giving the predator calcium for its own shell. Natalina even will save these empty shells in a special place to use in time of need. Despite this their shells are thin and fragile.New Zealand Rhytidids have a very thick periostracum. The english name of these group of snails is Cannibal snails,it is not uncommon for them to eat one of their own species. Mating seems to be a relatively short affair,about two hours,other snailspecies can take a whole day. In South-Africa two genera of Rhytididae can be found,Nata and Natalina.The genital opening in Nata lies just below the pneumostome,in Natalina this is behind the right tentacle. Also the sensory palps can not be found in Nata.

Genus Austrorhytida Genus Delos Genus Diplomphalus Genus Natalina Genus Nata Genus Ouagapia Genus Paryphanta Genus Rhytida Genus Schizoglossa Genus Victaphanta Family Acavidae Family Caryodidae Genus Anoglypta Genus Brazieresta Genus Caryodes Genus Hedleyella Genus Pedinogyra Family Macrocyclidae Genus Macrocyclus Family Chlamydephoridae Genus Chlamydephorus Family Haplotrematidae Family Plectopylididae Genus Plectopylis

Nata vernicosa Krauss,1848 Shell:Thin,whorls rounded and umbilicus wide,glossy,surface with fine,closely together axial riblets.Color transparant yellowish-brown,with sometimes darker,uneven, axial bands.Diameter seldom more than 20 mm. The animal has a pale to dark-bluish gray head and neck,with two longitudinal grooves running down the center.The tentacles are darker,sides of sole and sole pale. Habitat:Forests to open grasslands,gardens,to 2000 mtrs. Distribution:Very common in eastern South-Africa;Cape Town to Kruger National Park,Lesotho,Swaziland and the south of Mozambique.

Nata viridescens Melvill & Ponsonby,1891 Shell:Similar to N.vernicosa but more discoidal and lacks riblets. Diameter 5.0 mm. The animal has a dark grey head,neck and tentacles. Habitat:Like N.vernicosa. Distribution:Eastern South-Africa;Limpopo Province,Gauteng,Mpumalanga to Ithala Game reserve,and the KwaZulu-Natal Midlands.

Natalina cafra Ferussac,1821 Shell:Large,thin and fragile,with close-set axial riblets,upper part dull and base more glossy.Umbilicus narrow and aperture very large,oval. Color olive green,with darker and lighter axial bands. Diameter up to 75 mm. The animal is yellowish or cream,with the dorsal area of the head and neck brownish or grey. Habitat:In forests,montane grasslands,and gardens. Distribution:Eastern South-Africa;northern Pondoland to southern Zululand,to Drakensland,also in the Port Elizabeth-Grahamstown area.

Natalina wesseliana Kobelt,1876 Shell:Closely resembles N.cafra and used to be decribed as a form of that species. But lately it is looked upon as a real species.The aperture is significantly larger and more oblique.Diameter 70 mm. The animal has a more brown head and foot than N.cafra,with a rougher skin texture.The mantle has an orange tint. Habitat:Wooded areas,dune,coastal lowland. Distribution:Eastern South-Africa;central Zululand to south Mozambique.

Natalina beyrichi Martens,1890 Shell:Similar to N.cafra but umblicus wider and spire less elevated. Diameter 60 mm. Animal more brownish,edge of sole and mantle orange,the neck more brown. Habitat:Coastal forests. Distribution:Eastern South-Africa;Mkambati Nature Reserve to Dwesa Nature Reserve. Critically endangered.

Natalina quekettiana Melvill & Ponsonby,1893 Shell:The smallest Natalina species,spire low and whorls rounded,upper half of shell dull with close-set axial riblets,lower half glossy and smooth. Color olive-brown going to olive-greene below. Diameter to 30 mm. The animal has a dark-grey head and foot,paler towards the foot. Habitat:Forests in leaflitter. Distribution:Eastern South-Africa;in the Pietermaritzburg area,other localities unsure.

Family Chlamydephoridae Chlamydephorus burnupi Smith,1892 Description:A very notable slug for its distinctive keels running over the body.The posterior end has a large flat pad.The pneumostome is located in the center of this. The body is widest at this point and then slowly tapers towards the head. The lower keels are not as strong as the upper ones.Colouring bright orange to dark brown. The sides have sometimes grey markings.Length up to 80 mm. Habitat:Montane Podocarpus forest under rocks,tree trunks in grass and bracken. Distribution:Eastern South-Africa;in the foothills of the Drakensberg in KwaZulu- Natal to Port St Johns in Transkei.

Chlamydephorus sexangulus Watson,1915 Description:A large slug somewhat similar to C.burnupi but more slender and it doesn't have the flat pad. The upper keels come together behind the pneumostome and form a single short keel. Colouring orange-brown,with sometimes greyish-brown mottling,to dark brown or blackish. The sole is cream to pale yellow.Length 100 mm sometimes up to 170 mm. Habitat:Dune,coastal,lowland and Podocarpus forest under stones,logs and in leaf litter. Distribution:Eastern South-Africa;Zululand to the eastern Cape.

Chlamydephorus lawrencei Forcart,1963 Description:Like C.sexangulus but with 6-8 ridges which are rounded;first upper pair run until the pneumostome,second pair runs to the end of the body,third pair stops just before the end of the body.A fourth pair might be present:this start some distance from the head and ends some distance from the end of the body. Colouring chocolate brown to blackish,sole cream.Length 70 mm. Habitat:Wooded mountain slopes or savanna. Distribution:Eastern South-Africa;Barberton area,Vryheid Nature Reserve and Phinda Game Reserve,only three specimens are found so far.

Chlamydephorus dimidius Watson,1915 Description:A slug without keels and somewhat rounded in appearance.Colouring: head until just behind the pneumostome paler than the sides,buff to brown,normally with a central part which is darker.The pale area is bordered by a blackish band on each side.Sometimes broken up in fragments.The sides are brown to dark brown,towards the sole becoming paler. The sole itself is grey-brown with small dark spots.Skin texture looks a bit like snakeskin. Length 55 mm. Habitat:Coastal lowland and scarp forest in leaflitter and under logs. Distribution:Eastern South-Africa;KwaZulu-Natal.

Chlamydephorus gibbonsi Binney,1879 Description:A slug with a cylindrical body which tapers towards the head,lacks keels but has coarse reticulated skin.Two grooves in the middle of the back. Colouring orange with brown markings to dark brown with a pale brown dorsal line. Sole yellow to orangish-yellow.Length up to 110 mm. Habitat:Forest to open thornveld under stones and logs,in leaf litter,often living beneath the surface. Distribution:Eastern South-Africa;Zululand to East London and Transkei,inland to Pietermaritzburg and Colenso.

Source:Field guide to the land snails and slugs of eastern South Africa by Dai Herbert and Dick Kilburn
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