The bug guide
An identification and information guide for Moreton Bay and Balmain bugs Key di˜erences between Moreton Bay bugs and Balmain bugs
The key di˜erences between Moreton Bay bugs and Balmain bugs In addition, Moreton Bay bugs have no postero-lateral teeth on relate to eye position and the presence (or absence) of postero- the head, while Balmain bugs have 6–8 individual teeth on each lateral teeth on the ‘head’. side of the head (Figure 1). Moreton Bay bugs have their eyes positioned laterally on the outer edge of the carapace, while Balmain bugs have eyes positioned centrally on the dorsal surface of the carapace (Figure 1).
Eyes positioned laterally on the outer edge of the carapace Eyes positioned centrally on the carapace surface
Lack of segmentation Presence of (postero-lateral teeth) segmentation on the body (postero-lateral teeth) on the body
Moreton Bay bug Balmain bug
Figure 1. Distinguishing features of Moreton Bay and Balmain bugs (dorsal view) Bug classification key
Position of eyes
Eyes positioned laterally on Eyes positioned centrally the outer edge of the carapace on top of the carapace
Moreton Bay bug Balmain bug Minimum size limit 7.5 cm Possession of berried Possession of berried females females not permitted permitted above this size
• Cervical incision • Cervical incision gap is narrow gap is wide • Dorsal surface is covered with soft • Speckled legs • 6–7 postero-lateral • 7–8 postero-lateral hairs that have a • Striped legs teeth teeth • Red/brown colouration ‘velvety’ feel • Multiple incisions • No incisions • Tail is white/pale running across the running across the in colour mouthparts mouthparts
Ibacus chacei Ibacus brucei Ibacus alticrenatus Thenus australiensis Thenus parindicus (‘Garlic bug’) (‘Honey bug’) (‘Velvet bug’) (‘Reef bug’) (‘Mud bug’) Minimum size Minimum size Minimum size limit 10.5 cm limit 7.5 c m limit 7.5 c m Moreton Bay bugs
Moreton Bay bugs live in muddy or sandy bottoms up to a depth Thenus parindicus of 100 m. They belong to the genus Thenus of which there are two (Mud bug) main species—reef bugs (Thenus australiensis) and mud bugs The mud bug di˜ers from the reef bug by the presence of stripes on (T. parindicus). its walking legs (Figure 2). Mud bugs live on muddy substrates in depths of 10–50 m. While Thenus australiensis mud bugs have a similar distribution to reef bugs, they are more (Reef bug) commonly associated with commercial catches of tiger, banana The reef bug is distinguished by its reddish-brown colour and the and endeavour prawns. presence of speckling on its walking legs (Figure 2). Reef bugs live on sandy substrates in o˜shore waters in depths of Legal size: Minimum carapace width 7.5 cm. The possession of 30–100 m and are associated with scallop and redspot king prawn berried (egg-bearing) females above this size is permitted. fisheries. They are distributed from northern Australian coastal waters from northern New South Wales to Shark Bay in Western Australia.
Legal size: Minimum carapace width 7.5 cm. The possession of
berried (egg-bearing) females above this size is permitted. Moreton Bay bugs Figure 2. 2. Figure bug) (Reef australiensis Thenus colour Reddish-brown Dist on walk on S peckling or spots spots or peckling inguish g legs ing legs
Distinguishing features of Moreton Bay bug s bug Bay Moreton of features Distinguishing
ing Moreton Bay bug features cies ( pecies rsal view) view) dorsal Thenus parin Thenus Stripes on walking legs legs walking on Stripes (Mud bug) bug) (Mud cus dicus
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lour. Distinguishing Balmain bug features (head and body)
Gap between the head and the body Gap between the head and the body (cervical incision) is narrow (cervical incision) is wide
6–7 segments 7–8 segments (postero-lateral teeth) (postero-lateral teeth) on the body on the body
Ibacus chacei Ibacus brucei (Garlic bug—referred to in legislation as smooth bug) (Honey bug—referred to in legislation as shovel-nosed lobster)
Figure 3. Distinguishing features (head and body) of Balmain bug species (dorsal view) Balmain bugs Distinguishing Balmain bug features (mouthparts)
Dorsal surface covered with soft hairs Ibacus chacei (giving it a ‘velvety’ feel) (Garlic bug) Multiple incisions running across the mouthparts
Ibacus brucei (Honey bug) No incisions running across the Tail sometimes white mouthparts or pale in colour
Ibacus alticrenatus (Velvet bug—referred to in legislation as deepwater bug) Figure 3 (cont.). Distinguishing features (head and body) of Balmain bug species (dorsal view) Figure 4. Distinguishing features (mouthparts) of Balmain bug species Balmain bugs