Memoirs of the Museum of Victoria 53(2): 267-308 (1992)
FOUR NEW OCTOPUS SPECIES OF THE OCTOPUS MACROFUS GROUP
(CEPHALOPODA: OCTOPOD1DAE) FROM THE GREAT BARRIER REEF, AUSTRALIA
By Mark D. Norman
Invertebrate Zoology. Museum of Victoria. 285 Russell Street, Melbourne, Victoria 3000, Australia
Norman, M.D., 1992. Four new octopus species of the Octopus macropus group (Cepha-
lopoda: Octopodidae) from the Great Barrier Reef, Australia. Memoirs of the Museum of
Victoria 53: 267-308.
Four new species of shallow-water octopuses are described from tropical waters of the
Great Barrier Reef, Australia. All four are members of the "Octopus macropus group" (Rob-
son. 1 929). characterised by arms of unequal length with the dorsal pair longest (AF 1 .2.3.4),
moderate to high gill lamellae counts (10-14 per demibranch) and a robust conical copu-
latorv organ. All are nocturnally active. Two species. O. alpheus and O. aspilosomatis spp.
nov occur in clear waters foraging predominantly on intcrtidal coral reefs and offshore
islands. O. dierylhraeus sp. nov. forages intertidally and subtidally on muddy substrates in
coastal waters. Octopus graptUS occurs in more open waters, on sandy and mud substrata in
the channels and flat bottoms between islands. Full morphological descriptions arc pro-
vided, along with details of known distributions, life history and commercial exploitation.
Delineation of each species from related taxa is discussed.
A number of workers have recognised the dis-
tinctive group of octopus species often referred
to as the "Octopus macropus group" (Robson,
1929; Adam, 1941; Taki, 1944, 1964; Voss.
1981). Members of this species group are found
in most tropical and temperate waters of the
world and are characterised primarily by
elongate arms with the dorsal pair longest (AF
1 .2.3.4), moderate to high gill counts (10-1 4 per
demibranch), a moderately large cylindrical
copulatory organ with deep grooved ligula. and
nocturnal activity patterns.
The species from which this group derives its
name. Octopus macropus Risso, 1826, was
described from the Mediterranean Sea. This
species appears limited to the Mediterranean
Sea and temperate eastern Atlantic (Hochberg,
Mangold and Norman, in prep.). A number of
species from Indo-West Pacific waters show
close morphological and behavioural similar-
ities with O. macropus. Asa consequence, many
of these species have regularly, and inappropri-
ately, been assigned the name O. macropus. both
within Australian waters [Girard, 1 890; Brazier.
1892;Odhncr, 1917;Nesis, 1982 (plate in 1987
abridged translation); Lu and Phillips, 1 985], as
well as elsewhere in the Indo-West Pacific region
(Joubin, 1894, 1898: Goodrich, 1896; Hoyle,
1904: Berry, 1912. 1914; Wiilker, 1913. 1920;
Massv, 1 91 6; Sasaki. 1920; Robson, 1926. 1929,
1932: Boone, 1938; Adam, 1939, 1942, 1946,
1954, 1959, 1960, 1973; Rces and Stuckey,
1954-Voss, 1963; Roper et al., 1984).
Sasaki ( 1 920) was the first to question the sup-
posed wide distribution of O. macropus, when
tentatively assigning the name to a Japanese
species: "(there is) much doubt whether the
species extends as far as the Japanese waters
from its home; that is, the Mediterranean Sea".
Significant physical and temperature bound-
aries separate the distribution of the Indo-West
Pacific species from that of O. macropus and
there is no doubt that the Indo-West Pacific
species are distinct taxa. A major review of the
Indo-West Pacific members of the O. macropus
group is required, including re-examination of
species names from these waters previously syn-
onymised under O. macropus (Robson, 1929;
Roper et al., 1984).
Recent research into the shallow-water octo-
puses of the Great Barrier Reef and northern
Australia has uncovered a surprisingly rich octo-
podan fauna (Norman, 1991, 1992a, 1992b, in
prep.). At least 25 species have been recognised
from these waters, of which only five can be
assigned to previously described taxa. Amongst
this rich fauna are five members of the O. macro-
pus group. Octopus ornatus Gould, 1852 is a
large species widely distributed throughout the
tropical Indo-West Pacific. Norman (in prep.)
describes the morphology of this species and its
occurrence in Australian waters. The remaining
four taxa are described here as new species: O.