Author: (Bleeker, 1867)
Field Marks:
This squat, broad, anglerlike shark with profuse, highly branched dermal lobes on its head, a beard of similar lobes on its chin, and reticulated colour pattern of narrow dark lines and dark spots at their junctions on a light background is unmistakable; also, mouth in front of eyes, a symphyseal groove on chin, very broad pectoral and pelvic fins, two spineless dorsal fins and an anal fin, the first dorsal origin opposite the pelvic hindbases, the anal origin well behind the second dorsal origin.
Diagnostic Features:
Head and body very broad, without enlarged tubercles on body, except for those above eyes. Trunk width across pectoral insertions about equal to head length; precaudal tail rather short, distance from pelvic insertion to lower caudal origin about equal to head length. Head width slightly greater than its length from snout tip to fifth gill openings; chin with a bushy beard of highly branched dermal lobes; dermal lobes of sides and front of head highly branched and numerous, forming a virtually continuous fringe from snout tip to pectoral bases; nasal barbels branched, with complex multiple lobes. Dorsal fins high and short, height of first about equal to its base length, length of first dorsal base less than pelvic length from origin to free rear tip; origin of first dorsal fin opposite posterior fourth of pelvic bases; interspace between first and second dorsal fins longer than first dorsal inner margin and slightly more than half first dorsal base; pectoral and pelvic fins very large, distance from pectoral insertions to pelvic origins about equal to pectoral bases and less than pelvic bases from origins to free rear tips. Colour: dorsal surface with a reticular pattern of narrow dark lines on a light background, with scattered symmetrical enlarged dark dots at the junction of lines.
Geographical Distribution:
Western South Pacific: Indonesia (Waigeo, Aru, Irian, Jaya), Papua New Guinea, ? Malaysia, Australia (northern Queensland, Northern Territory, Western Australia).
Habitat and Biology:
A little-known inshore tropical bottom shark, present on coral reefs. Said to be a faster swimmer than other wobbegongs (Whitley and Pollard, 1980), but its more flattened shape and bushy beard of dermal flaps suggests the reverse, that it might be more sluggish than other wobbegongs. Probably ovoviviparous and probably feeding on bottom invertebrates and fishes. According to an informant quoted by Whitley (1940), this shark "...attacks and generally kills the natives" in Papua-New Guinea; this shark no doubt should be considered dangerous and to be treated with respect, but the fearsome reputation of this shark may be exaggerated. Divers have approached and photographed the tasselled wobbegong during the daytime, without inciting attacks, though probably stepping on or near this very well-camoflaged shark might cause it to bite at least in self-defense or by mistaking a human foot for its usual prey.
Size:
Maximum total length said to be 366 cm but this is uncertain. An adult male examined by the writer from New Guinea is 117 cm long; the 22 cm syntype is newborn or close to it.
Interest to Fisheries:
Uncertain, probably minimal; the tough skin with its handsome reticulated colour pattern is potentially valuable for leather.
Remarks:
The separation of the Australian Eucrossorhinus ogilbyi (Regan, 1909) from this species is unsatisfactory. Regan (1909) distinguished the two as follows:
Ogilbyi. Gill slits decreasing in size from first to fourth, last larger; last two closer together than rest. Dermal lobes on sides of head in three separate groups. Origin of first dorsal fin well behind middle of total length. Distance between origins of dorsals nearly half that from origin of second dorsal to end of tail.
Dasypogon. First gill slit slightly smaller than rest, which are of equal size and equidistant. Dermal lobes on head in two separate groups. Origin of first dorsal fin in the middle of total length. Distance between origins of dorsals slightly more than 1/3 that from origin of second dorsal end of tail.
The present writer was able to compare the syntype listed above with a larger specimen of putative E. ogilbyi from northern Queensland (BMNH 1911.4.1.43, 415 mm female), as well as a much larger specimen of E. dasypogon from Papua New Guinea (Australian Museum, Sydney, AMS 14783, 117 cm adult male). This indicated that the characters supposed to separate the two species do not hold.
All three specimens had the last two gill slits more closely spaced than the other three, though the larger ogilbyi and dasypogon had them slightly closer than the small syntype. All three specimens have the first four gill slits about equal length or with the first slightly smaller; the fifth is slightly smaller than the fourth in the small dasypogon, slightly larger in the large dasypogon, and about equal to it in the ogilbyi. In the small dasypogon and the ogilbyi the first dorsal origin is actually slightly ahead of the midlength, and slightly behind in the large dasypogon (an indicator of allometric increase in abdominal length with growth). The small dasypogon has the first dorsal to second dorsal origin 2.7 in the distance from the second dorsal origin to the caudal tip, the ogilbyi 2.6, and the large dasypogon 2.4.
None of the differences listed above suggest anything more than individual and ontogenetic variation in a single species. As the three specimens examined are otherwise strikingly similar in colour pattern and general morphology, and there is nothing in the literature to suggest any significant differences between Australian, Papua New Guinean and Indonesian Eucrossorhinus, I propose to synonymize E. ogilbyi with E. dasypogon.
Type material:
Syntypes: British Museum (Natural History), BMNH 1867.11.28.209, 215 mm immature male, one of two described by Bleeker from Waigiu (Waigeo). Type Locality: Waigiu and Aru, Indonesia.