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False-eye Seahorse Hippocampus biocellatus Kuiter, 2001
[CAAB 37 282115]

Distribution Map see an interactive map here (new window)

The pair of "eye spots" or ocelli on the back of the False-eye Seahorse may protect he species by distracting predators.

Distribution, ecology and habitat:

Endemic to the Shark Bay region of Western Australia; benthic on algal reefs and seagrass beds in protected shallow bays from the intertidal zone to about 20 m.

Size:

Height to about 110 mm.

Food and feeding:

Like other seahorses, this species presumably preys on small crustaceans and other small invertebrates by sucking them in through the tubular snout.

Reproduction and early life history:

Reproduction: Sexes separate, reproduction a form of viviparity or ovoviviparity, whereby the males give birth to tiny independent young. The female uses an ovipositor to transfer her eggs into an elaborate enclosed pouch under the abdomen of the male. The male not only fertilizes the eggs inside the pouch and provides physical protection for the developing embryos, he also osmoregulates and aerates the embryos and may provide some nourishment until the offfspring are born.
Eggs: Not described.
Larvae: Not described.

Characteristics:

Meristics: D 22-23; P 16-18; A 4-5 (rays divided at base); trunk rings; tail rings 36-38; subdorsal rings 3 + 1-2.
Head and body: Head moderately long; snout moderately long; nasal ridge slightly raised, spine absent; a thick membranous keel of skin present along edge of ventral trunk ridge.
Spines: Spine above eyes moderately large, angled back and laterally outward; lateral head spine moderately large, recurved; spines behind and below eye small; upper shoulder-ring spine small to moderate, beside gill opening; central shoulder ring spine small, tubercle-like, lower shoulder ring spine moderate, directed laterally outward; subdorsal spines 4-5/0,0,1,1; superior trunk and tail ridges with broad thorn-like blunt spines, enlarged at regular intervals on some rings; superior tail ridge with tubercle-like spines of moderate size, angled  backward; trunk ridges and connecting tail ridges with spines and tubercles becoming gradually smaller posteriorly.
Coronet: Coronet slightly raised, apex with 5 blunt diverging spines.
Lateral line: Lateral line with distinct pores, on trunk rings just above lateral ridge, continuing onto 18^th-23^rd tail ring, each pore between raised papillae.

Colour:

In life, body with blotched pale cream-grey to pale brown patterns, and blackish scribbles and fine yellowish cream spots; head often with thin black lines around eye and over operculum; two distinct black ocelli surrounded with yellow laterally on upper sides of the trunk, situated on enlarged superior ridge spines of 4^th and 7^th rings. Dorsal fin with two thin longitudinal dark lines, one along fin margin, the other through centre of fin. In preservative - similar  to fresh material, with dark colours reddish-brown and black spots on back remaining distinct.

Similar species:

H. biocellatus is similar to H. planifrons, differing in colour pattern and in having a longer, more slender trunk and generally smaller spines, especially subdorsally.

Fisheries:

No known international trade for the aquarium industry.

Conservation Status:

International: Listed under Appendix II of the Convention on the International Trade in Endangered Species of Wild Flora and Fauna (CITES).
Australian legislation: Marine Listed under the Federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act 1999).

Remarks:

Males have a deep keel-like skin membrane on the ventral trunk ridge that may be used during courtship displays.

Other common names:

False-eyed Seahorse

Original citation:

Hippocampus biocellatus Kuiter 2001, Rec. Aust. Mus. 53: 311, fig. 15, Shark Bay, Western Australia.

Etymology:

Hippocampus is from the Greek, ippos = horse and kampe = curvature. The specific name biocellatus is from the Latin bi (two) and ocellus (eye) in reference to the eyelike spots on back.

References:

Hoese, D.F., D.J. Bray, J.R. Paxton & G.R. Allen. 2006. Fishes. In Beesley, P.L. & A. Wells. (eds.) Zoological catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia, 2178 pp.

Kuiter, R.H. 2000. Seahorses, Pipefishes and their Relatives. TMC Publishing, Chorleywood, UK, 240 pp.

Kuiter, R.H. 2001. Revision of the Australian Seahorse of the genus Hippocampus (Syngnathiformes: Syngnathidae) with descriptions of nine new species. Rec. Aust. Mus. 53: 293-340.

Pogonoski, J.J., D.A. Pollard & J.R. Paxton. 2002. Conservation Overview and Action Plan for Australian Threatened and Potentially Threatened Marine and Estuarine Fishes. Canberra, Environment Australia, 375 pp.