(Figs. 2–3)
Octopus tetricus, Joll et al. 1976, 1977, 1978; Roper et al. 1984: 209; Kirkman et al. 1991: 557; Stranks 1998: 541 (in part); Guerra et al. 2010: 1405 (in part); Acosta-Jofre et al. 2012 (in part); Reid & Wilson 2015 (in part); Greenwell et al. 2019.
Octopus cf. tetricus, Roper 1997; Norman & Reid 2000; Finn et al. (2005); Guzik et al. 2005; Norman & Hochberg 2005: 146; Amor et al. 2014; Norman et al. 2014: 58; Leporati & Hart 2015; Leporati et al. 2015; Hart et al. 2016; Reid 2016: 396; Amor et al. 2017; Sauer et al. 2020; Somaweera & Somaweera 2021.
Octopus aff. tetricus, Hart et al. 2019.
Type material. Seven type specimens were designated, including at least one male and one female from each sampled locality which encompasses most of the species’ distribution. Other material examined (a further 7 males and 11 females) are listed in Table 1 (n = 25). Raw morphological data are available in Tables S1–S 4. Holotype: AUSTRALIA: Western Australia: Esperance: Male, 138.6 mm ML (Fig. 3). Collected by M. Amor 10-Dec-2019 via non-baited trap, 7–9 m depth. Esperance Bay (-33.84, 121.91) (WAM S.89010). Paratypes: AUSTRALIA: Esperance: (i) Female, 163.4 mm ML. Collected by M. Amor 10-Dec-2019 via non-baited trap, 7–9 m depth. Esperance Bay (-33.84, 121.91) (WAM S.89009); Mandurah: (ii) Male, 163.4 mm ML. Collected by M. Amor 12-Dec-2019 via baited trap, 22–25 m depth (-32.77, 115.53) (WAM S.89021); (iii) Male, 177.0 ML. Collected by M. Amor 12-Dec-2019 via baited trap, 22–25 m depth (-32.75, 115.51) (WAM S.89022); (iv) Female, 124.3 mm ML. Collected by M. Amor 12-Dec-2019 via baited trap, 22–25 m depth (-32.78, 115.52) (WAM S.89018); Geraldton: (v) Male, 176.1 mm ML. Collected by M. Amor 2-Dec-2019 via baited trap, 16–30 m depth (-28.83, 114.55) (WAM S.89001); (vi) Female, 149.7 mm ML. Collected by M. Amor 2-Dec-2019 via baited trap, 16–30 m depth (-28.92, 114.57) (WAM S.89006).
Diagnosis. Medium to large (109–177 mm ML), muscular species. Ocelli absent. Long arms taper to narrow tips between 347–745 mm; 3.7–6 times longer than ML. All arms equal width (12.5-32.1 mm). Males right arm III hectocoltylised; shorter than opposite arm (ALR3 84–97% ALL3). Well-defined spermatophore groove ends at base of small calamus. Calamus approximates 31–49% of ligula. Small ligula (LL 1–1.6% ALR3). Biserial sucker arrangement; 182–283 suckers on non-hectocotylised arms, 169–196 hectocotlised arm suckers. Between 1–13 enlarged suckers present in both sexes; between 10 th to 23 rd proximal suckers on II and III arm pairs.
Description. Based on 11 mature males and 14 sub-mature females. Mantle broad, oval shaped and saccular. Web depth 18–31% of longest arm, formula highly variable. Funnel tube shaped; free length 45–85% of total funnel length (39–66 mm). Funnel organ ‘W’ shaped. 9–10 lamellae per gill demibranch. Ink sac, anal flaps present. One large papilla above each eye, 2–3 additional smaller papillae adjacent. Typical Octopus digestive tract (Fig. 4) comprising a large buccal mass connected to a pair of rounded anterior salivary glands. Posterior salivary glands curved and triangular. Narrow oesophagus leads to crop diverticulum then wide, triangular, stomach. Spiral caecum connected to large digestive glad; ink sac embedded within. Long intestine ending with muscular rectum, pair of anal flaps. Strong beak embedded within buccal mass (Fig. 5A & 5B). Radula comprises rows of seven teeth, two marginal plates. Rhachidian tooth, 2–3 cusps migrating laterally, and asymmetrically over four rows. Pattern offset by two rows (WAM S89017; Fig. 5C).
Spawned eggs 2.5 mm long, 1 mm wide. Larvae planktonic. Mature male testis, large (Fig. 6A), narrow vas deferens opens into a round mucilage gland, then long, curved spermatophore gland (Fig 6B & 6C). Spermatophore sac connected, 32–111 spermatophores within. Spermatophores long (to 50 mm), and narrow (0.6–0.7 mm). Terminal organ 13–24% of ML. Diverticulum elongate, oval-shaped (5–14 mm). Ovaries to 28 g (sub-mature). Short proximal oviducts, lead to spherical oviductal glands and distal oviducts (Fig. 6D).
Rough skin texture, distinct patches. Live specimens display mottled colour pattern, vary in colour from oceanic (reddish-brown/orange) to estuarine habitats (green/brown tint). Characteristic orange colouration along arm edge; often displayed while denned. Colour muted by preservation.
Distribution. Shark Bay (northernmost distribution; approx. -25.51, 112.87) to Cape Le Grand (southeast; approx. -33.94, 122.55), Western Australia (Fig. 1). Depth to 80 m. Mean sea surface temperatures from ~25–17 (Fig. S1; Huang et al. 2017).
Etymology. Octopus djinda, sp. nov, the star octopus, is distributed along the southwest coast of Australia. This distribution closely reflects the territory of the traditional custodians of this land, the Nyoongar people (‘a person of the southwest of Western Australia’). To recognise their connection to this land, a Nyoongar translation of ‘star’ (djinda), as described by Whitehurst (1997), was selected as a species name. This use of ‘star’ (luminous) reflects the shared recent ancestry with, and now-understood distinction from, O. tetricus (Latin: gloomy octopus). Consultation with the Aboriginal community regarding the use of ‘djinda’ as a species name was undertaken via the Western Australian Museum’s Aboriginal Advisory Committee (WAMAAC). Initial documentation, including the above etymology statement, was presented to the committee on Friday July 2, 2021. Support was provided on July 14, 2021.
Remarks. Greater, and non-overlapping, sucker numbers on hectocotylised arm delimit O. djinda, sp. nov. (169–196) from O. tetricus (122–150; Amor et al. 2017) and O. sinensis d’Orbigny, 1841 from Asia (119–152; Gleadall 2016), but not Kermadec Is. (178–185; Reid & Wilson, 2015). Disjunct distributions reflect species identity among O. djinda, O. tetricus and O. sinensis, which form a monophyletic clade within the O. vulgaris group (Amor et al. 2019). A 399 bp fragment of the COI gene was sequenced to complement visual identification. Sequence data from 16 individuals, that were of sufficient quality, were retained and represented a single haplotype. 349 bases overlapped with existing accessions for O. tetricus and O. cf. tetricus. 13 polymorphisms along 349 bp partial COI sequence (3.7% divergence) reliably distinguish O. djinda, sp. nov. from O. tetricus; interspecific variation nine times greater than intraspecific differences. Four characteristic large papillae form a diamond pattern on the dorsal mantle, typical for the O. vulgaris species-group. Funnel organ was difficult to see in most specimens.