81 photos - 47 species


Introduction


They are leaf-like creatures with often brightly coloured patterns.

They nestle their flat bodies close to the respective substrate

and glide over the coral with flowing movements.

They swim with wave movements.


Some of these flatworms have not yet been described,

i.e. there are no scientific or English designations


Acanthozoon sp

Acanthozoon sp

Maximum length: 80 mm

This worm is a predator that is active in the dark.

It kills snails and small hermits by enveloping them and sucking them in.

Photos 1 - 2 Johnny: Lembeh Strait North - Sulawesi


Cycloporus venetus ( Newman & Canon, 2002 )

Blue flatworm, Marineblue flatworm

Maximum length: 1.5 - 5 cm

Maximum depth: 15 m

This flatworm feeds on sea squirts ( Botryllus violaceus ),

which it eats with its mouth on the ventral side.

Light to dark blue back, often with a white line in the middle,

a thin yellow border and a darker spot in the middle of the head.

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Cycloporus sp.

No english designation

Not yet described, therefore no data to be found.

This one had a size of 3 - 4 cm and was in a depth of 12 m

Photos 1 - 2 Astrid: Bangka island North Sulawesi


Eurylepta sp

 Eurylepta sp

 Maximum length: 55 mm

The basic body colour of the swirl worm is intense yellow.

There are different nuances in the colour intensity of the large spots.

They range from brownish to black.

Eurylepta with the dark, almost black spots mimics the nudibranch Phyllidia polkadotsa

(a species of warty snail).

Both look confusingly similar.

Photo 1 Johnny: Bangka Island North - Sulawesi

Photo 2 Johnny: Lembeh Strait North - Sulawesi


Eurylepta sp

 Eurylepta sp

 Maximum length: ?

Exact ID not yet possible, as not yet described.

White body, with orange mantle edge with black border.

Photo 1 Johnny: Bangka Island North Sulawesi


Eurylepta sp

 Eurylepta sp

 Maximum length: ?

Exact ID not yet possible as not yet described.

Grey - cream body, with two broad black stripes edged with grey and yellow mantle edge.

Photo 1 Johnny: Bangka Island North Sulawesi


Maritigrella fuscopunctata

Darkspotted fatworm or Punctuated flatworm

 Maximum length: 22 mm

Maximum depth: 5 - 20 m

Mostly found singly or in pairs in coral reefs

and rocky reefs under sand and rubble.

By using tiny hairs on the ventral side like little feet,

the worm is able to move quite quickly.

This speed benefits the animal when catching prey,

as it pushes itself completely over its victims and then sucks them dry.

Photos 1 - 2 Johnny: Bangka Island North - Sulawesi


Nymphozoon orsaki

Orsak's flatworm

 Maximum length: 35 mm

Edge strongly wavy. They have 3 to 5 female and 2 male genital pores.

Photo 1 Johnny: Embudu Maldives


Pseudobiceros bedfordi

Persian carpet flatworm or Elegant flatworm

 Maximum length: 6 cm

This flatworm is known as the Persian carpet whirlpool worm,

which fits its pattern quite well.

Photo 1 Johnny: Bangka Island North Sulawesi


Pseudoceros ferrugineus

Fuchsia flatworm

 Maximum length: 80 mm

Maximum depth: up to 20 metres

A beautiful swirl worm, a strong yellow band runs around the outside of the body,

followed by a somewhat difficult to recognise red band,

before the beautiful fuchsia colour and the small white dots make up the rest of the body.

Photos 1 - 2 Astrid: Lembeh Strait North - Sulawesi

Photo 3 Johnny: Lembeh Strait North - Sulawesi


Pseudobiceros flavocanthus

Flatworm

Maximum length: 100 mm

This whirlpool worm has a brown body with a white and yellow border.

It feeds on colonial sea squirts.

Photos 1 - 2 Johnny: Lembeh Strait North - Sulawesi


Pseudobiceros flowersi

Flower's flatworm

 Maximum length: 80 mm

Maximum depth: 23 m

This very pretty whirlpool worm is widespread in the Indo-West Pacific

and lives there under rubble and sand in rocky reefs.

Diet: Snails, mussels and sea squirts. 

It is particularly striking due to its intensely wavy mantle edge.

The colour varies from a light olive green to dark brown to black.

A light-coloured longitudinal line is clearly visible in the centre.

Oval body with tapering towards the rear.

Photos 1 - 2 Johnny: Bangka Island North - Sulawesi


Pseudobiceros fulgor ( Newman & Cannon, 1994 )

Fine - lined flatworm, Lightning flatworm, Brilliant flatworm

Maximum length: 8 - 10 cm

Maximum depth: 12 m

Orange-brown colored body, on the surface is an intricate pattern of fine, light lines

Ruffled black mantle edge, plain pink underside.

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudobiceros gratus ( Kato, 1937 )

Pleasing flatworm

Maximum length: 5.5 cm

Maximum depth: 1.5 - 24 m

The species name gratus is Latin and means pleasant.

Basic body color: Varies from transparent white to light brown

with three or four parallel thick shagreen stripes.

Found in reefs, on rocky outcrops and in lagoons.

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudobiceros hancockanus ( Collingwood, 1876 )

Polyclad flatworm

Maximum length: 14 cm

Maximum depth: 3 - 14 m

Lives among coral fragments or stones in coral reefs in warm seas.

Dark brown with a yellow edge and a white edge on the outside.

The pseudotentacles are similarly colored.

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudobiceros kryptos

Cryptic flatworm

 Maximum length: 40 mm

Maximum depth: 2 - 25 m

As you can see from the pictures, this worm can be found on stony,

rocky grounds where the animal quickly finds sufficient protection from predators.

The colouration varies between a blotchy olive green

and a chalky greenish white with large irregular brown and olive green spots

on the edge and large irregular orange-brown and white spots scattered over its dorsal side.

The ventral side is light olive green. 

Photos 1 - 2 Johnny: Bangka Island North - Sulawesi


Pseudobiceros sp.

Pseudobiceros sp

 Maximum length: ?

Maximum depth ?

Unfortunately I couldn't find out anything about this species,

maybe it will be described sometime.

Photo 1 Johnny: Bangka Island North - Sulawesi


Pseudobiceros sp.

Pseudobiceros sp

Maximum size: 5 cm

Maximum depth: ?

Black body with a bright yellow centre line and radiating lines towards a yellow edge.

Found in shallow water in about 8 metres under a reef top.

Photo 1 Johnny: Bonaire Caribbean

Photo 2 Johnny: Bonaire Caribbean 


Pseudobiceros sp.

Pseudoceros sp

This as yet undescribed swirl worm has a dark,

burgundy-brown to black ground color,

with a network of white lines

as well as yellowish and dark roundish spots.

A somewhat difficult pattern to describe, but see for yourself in the pictures.

The edge of the mantle has white lines and is wavy.

The pseudotentacles are formed from the edge of the mantle, as with all whirlworm species.

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudobiceros sp.

Pseudoceros sp

An as yet undescribed species, therefore unfortunately no description

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudobiceros sp.

Pseudoceros sp

An as yet undescribed species, therefore unfortunately no description

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudoceros bicolor

Bicolored flatworm

 Maximum size: 4.5 cm

Maximum depth: 1 - 11 m

Not much is known about this species either.

Occasionally the white edge is coloured greenish yellow.

Photos 1 - 2 Johnny: Bonaire Caribbean


Pseudoceros bimarginatus

Flatworm

 Maximum length: 100 mm

Maximum depth: 2 - 20 m

Often found in shallow lagoons and shallow reefs.

The white to cream-coloured whirlpool worm has 3 characteristic edge bands

that run from the inside to the outside in yellow-green, black and orange.

Some of them have a thin white centre line.

It has pseudotentacles.

Photos 1 - 3 Johnny: Bangka Island North - Sulawesi


Pseudoceros dimidiatus

Divided flatworm or Tiger flatworm

 Maximum length: 80 mm

There are 2 variants of them, black with yellow stripes and yellow with black stripes,

unfortunately I have only seen this variant so far.

The fringe is orange.

It lives in sheltered lagoons and bays.

Photo 1 Johnny: Lembeh Strait North - Sulawesi

Photos 2 - 3 Johnny: Hurghada Egypt


Pseudoceros fuscomaculatus

Ascidian flatworm

Maximum length: 2 cm

Maximum depth: 10 m

This whirlpool worm lives exclusively on the green sea squirt Didemnu molle

and also feeds on it.

Top and underside semi-transparent, white speckled.

About 20 short round papillae cover the entire dorsal surface.

Photo 1 Johnny: Bangka island North Sulawesi


  Pseudoceros indicus

Blue-dotted flatworm or Indian flatworm

 Maximum length: 60 mm

The white whirlpool worm with its distinctive blue spots can be found

between mangrove roots, but also near the coast in muddy intertidal areas,

under stones and dead oysters.

As a food specialist, it feeds on white and yellow colonial sea squirts.

The name ‘indicus’ is derived from the Latin word meaning ‘blue ink’.

Photo 1 Johnny: Lembeh Strait North - Sulawesi


Pseudoceros lindae

Linda's flatworm or Polyclad faltworm

 Maximum length: 80 mm

Maximum depth: 27 metres

As this worm has a warning colouration ( aposematism ),

which signals that it is inedible, it can be active on the reef during the day,

although with its size of up to 80 mm it could make a good snack for predators.

Diet: Sea squirts, the poison of which it stores in its own body.

Burgundy base colour, with large, irregularly distributed, oval to round,

golden-yellow spots.

Blue mantle edge.

Widely distributed in the Indo-Pacific and, like snails, a hermaphrodite,

i.e. two flatworms are able to fertilise each other,

as each animal has both a penis and a vagina.

Photos 1 - 2 Johnny: Bangka Island North - Sulawesi


 Pseudoceros liparus

Racing-stripes flatworm

Maximum length: 60 mm

Blue body with a white centre stripe and dark edge lines

There is an orange spot on the front of the stripe.

Photos 1 - 2 Johnny: Lembeh Strait North - Sulawesi


Pseudoceros paralaticlavus

Goldrim flatworm

 Maximum length: 50 mm

Maximum depth: 2 - 23 m

Only becomes active at nightfall, then goes in search of food.

Its body is cream-coloured, followed by a broad black stripe

and then a thinner yellow stripe.

Photos 1 - 2 Bangka Island North - Sulawesi 


Pseudoceros rubronanus ( Newman & Cannon, 1998 )

Red dwarf flatworm

Maximum length: 0.8 - 2 cm

Maximum depth: 10 m

The body is oval with a few marginal ruffles and bright red.

The pseudotentacles have small bumps.

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudoceros scintillatus

Brilliant flatworm or Sparkling flatworm

Maximum length: 60 mm

Maximum depth: 2 - 15 m

Diet: colonial sea squirts.

Basic body colour black, with a distinctive yellow to orange edge and large,

irregular yellow-green spots.

There is a whole range of colour variants with different patterns.

Photo 1 Johnny: Bangka Island North - Sulawesi


Pseudoceros scriptus

Script flatworm

 Maximum length: 5 cm

White body with orange margin and irregular black spots. 

Photo 1 Johnny: Bangka Island North Sulawesi


Pseudoceros sp.

Pseudoceros sp

 Maximum length: 3.5 cm

White body with yellow mantle, yellow stripe in the centre

and 2 black stripes on each side.

Probably warning colours for predators.

Photo 1 Johnny: Bangka Island North Sulawesi


Pseudoceros sp.

 Pseudoceros sp

Maximum length:65 mm

The swirl worm has a light blue marginal stripe, a pink body with white dots.

In the centre there is a yellow longitudinal stripe with a wine-red border.

Photos 1 - 3 Johnny: Lembeh Strait North - Sulawesi


Pseudoceros sp.

Pseudoceros sp

This as yet undescribed whirlpool worm is orange-brown in color

with a thin black longitudinal line.

A broad black band runs around the body of this swirl worm,

followed by an even wider white ruffled band.

The pseudotencae are blue.

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudoceros sp.

Pseudoceros sp

This as yet undescribed swirl worm has a reddish-brown base color,

with many white random speckles.

A dark spot can be seen just before its pseudotentacles.

The color of its pseudotentacles corresponds to the appearance of the body.

Photo 1 Johnny: Bangka island North Sulawesi


Pseudoceros sp.

Pseudoceros sp

This as yet undescribed swirl worm has a cream base color,

with a black, somewhat net-like, but irregular pattern.

The matt orange mantle edge also runs around the pseudotentacles folded out of the mantle

Photo 1 Johnny: Bangka island North Sulawesi


Pseudoceros sp.

Pseudoceros sp

This as yet undescribed swirl worm has an orange-brown base color,

with numerous thin, white criss-cross lines.

The edge of the mantle is decorated with white and black spots.

The rather inconspicuous pseudotentacles are folded out of the mantle

and have the same color pattern as the body.

Photo 1 Johnny: Bangka island North Sulawesi


Pseudoceros sp.

Pseudoceros sp

This as yet undescribed swirl worm has a reddish-brown base color,

with numerous, different, intense cream and yellowish speckles.

The inner edge of the mantle is solid reddish brown, corresponding to the ground color,

but free of speckles.

There is a broad white edge on the outside.

The inconspicuous, rather short pseudotentacles are folded out of the body margin

and have the same coloration as the body itself.

Photos 1 - 2 Johnny: Bangka island North Sulawesi


Pseudoceros sp.

Pseudoceros sp

This as yet undescribed swirl worm has a white, finely granulated ground color.

A black line runs down the center of the body, with a black elongated mark to the left and right of it.

black elongated markings to the left and right.

The margin consists of a broad, yellow band,

the entire body, including the pseudotentacles folded out of the mantle,

pseudotentacles folded out of the mantle.

This whirlpool worm imitates the appearance of a poisonous nudibranch

of the genus Chromodoris to protect itself from predators.

Photo 1 Johnny: Bangka island North Sulawesi


Pseudoceros susanae

Susan's flatworm

 Maximum length: 45 mm

I cannot describe this species,

I have only found out its name so far

Photos 1 - 2 Johnny: Embudu Maldives


Thysanozoon nigropapillosum

Yellow papillae flatworm or Gold-speckled flatworm

 Maximum length: 80 mm

Velvety black body surface framed by a white margin.

Yellow - orange coloured papillae on the body.

Photos 1 - 2 Johnny: Lembeh Strait North - Sulawesi

Photo 3 Johnny: Bangka Island North - Sulawesi


Thysanozoon flavotuberculatum

Yellowspot flatworm

 Maximum length: 50 mm

Golden yellow papillae on a black background with a white margin.

Two pseudotentacles on the margin. Lives on rubble

and sand in lagoons and outer reefs.

Photo 1 Johnny: Lembeh Strait North - Sulawesi


Undescribed

Unfortunately I cannot report anything about this species

because it is undescribed.

White to yellowish body with black mantle edge. 

The animal was about 3 - 4 cm long.

Photo 1 Johnny: Bangka Island North Sulawesi


Undescribed

 Unfortunately I cannot report anything about this species

because it is undescribed.

Brown body with orange mantle edge, the orange is edged with black. 

A whitish spot can be seen approximately in the centre of the body. 

The animal was about 1 - 2 cm long.

Photo 1 Johnny: Bangka Island North Sulawesi


Undescribed

 Unfortunately I cannot report anything about this species

because it is undescribed.

Cream-coloured body with blue mantle edge. 

In the centre of the body is a blue straight band.

The animal was about 3 - 4 cm long.

Photos 1 - 2 Johnny: Bangka Island North Sulawesi


Undescribed

 Unfortunately I cannot report anything about this species

because it is undescribed.

Blue-black body without further characteristics 

The animal was about 4 - 5 cm long.

Photo 1 Johnny: Bangka Island North Sulawesi