Hydroides cf. amri Sun, Wong, ten Hove, Hutchings, Williamson & Kupriyanova, 2015

(Figures 3, 11 A, Table 1)

Hydroides amri Sun, Wong, ten Hove, Hutchings, Williamson & Kupriyanova, 2015: 14 –20, Fig. 3 a–b, Fig. 4 a–h, Map 3. Type locality: South Bass Point, New South Wales, 34°36’12”S, 150°53’43”E, on rock.

Hydroides brachyacantha not Rioja, 1941a.— Dew 1959: 28 –29 (only in part, according to Sun et al. 2015); Straughan 1967: 222 (apparently only specimens from Jervis Bay, Sydney, according to Sun et al. 2015); Straughan 1969: 232 (Black Point, Oahu, Hawaii, sample from 1939); Bailey-Brock 1976: 77 –78 (Oahu Island, Hawaii, reef slope); Bailey-Brock 1987: 419 – 420, Fig. 3.II.189a–b (Hawaii).

Hydroides brachyacanthus not Rioja, 1941a.—Bastida-Zavala & ten Hove 2003: 75, Figs 3 L–M ( Oahu, Hawaii); Kupriyanova et al. 2006: 423, 430 (South Australia, DNA data); Kupriyanova et al. 2008: 428–431 (South Australia, DNA data). Eupomatus ralumianus not Augener, 1927.— Poore et al. 1975: 30 (Port Phillip Bay, Victoria, probably juvenile, according to Sun et al. 2015).

Material examined. 5 specimens.

Hawaii: LACM s.n., 5 spec. ( Oahu, Hawaii, five samples from 1972: X2-5, July 8; X3-2, July 9; X5-1, July 11; X14-3, July 17; coll. Dale Straughan).

Habitat. Intertidal to subtidal (20.5 m, Sun et al. 2015). Temperate waters, on natural substrates: rocks, sponges, weed & ascidians on boulders, Ecklonia radiata holdfasts, in mixed red algae, orange solitary corals, dead corals, bryozoan colonies, in calcareous algae and Idanthyrsus sabellariid tubes, platform rock with gullies, surf swept rock-flat and lagoon, under ledge, underneath boulders and in crevices in rock pools; on man-made substrates: woodchip berth, subtidal wharf pile, breakwater, and on hull of SS “Bonthorp” (Sun et al. 2015).

Distribution. Hydroides cf. amri is recorded only from Hawaii.

Remarks. Hydroides amri sensu stricto was collected in both natural and man-made substrates, including the hull of a ship (Sun et al. 2015); this species has potential to be introduced to other temperate and subtropical regions by ships.

Sun et al. (2015: 20) suggested that the specimens recorded from Hawaii as Hydroides cf. brachyacanthus by Bastida-Zavala & ten Hove (2003), probably correspond, morphologically, with H. amri, but also recommended additional studies to decide if Hydroides cf. brachyacantha from Hawaii is in fact H. amri . Re-examining the morphological data of the Hawaiian specimens, we can confirm that the characters of the opercula, mainly the three dorsal bigger spines, as well as the number of radioles, tube and thorax measurements, are more similar to H. amri than to H. brachyacantha sensu stricto (Table 1). Sun et al. (2016b) found that H. amri comprises two non-sister clades, and based on their genetic lineage described a new species from South Australia, Hydroides nikae Sun, Wong, Tovar-Hernández, Williamson & Kupriyanova, 2016b . The same may happen with H. cf. amri from Hawaii, but only a phylogenetic analysis could solve their identity, something that is out of the scope of this work.

Straughan (1969) mentioned “Smaller spines have a blunt tooth projecting from the outside of the curve”, a character that coincides with the description of Hydroides amri . Bailey-Brock (1976; 1987) recorded H. brachyacantha from the Hawaiian Islands and, at least in her work of 1987 (Fig. 3.II.189a–b) reproduces the figures of Dew (1959, Fig. 7) from Australia. In our opinion all historical records from Hawaii belong to H. cf. amri .

average: 0.99 1.45 2.55 0.87 2.83 12.70 11.04 4.06 0.84 28.55 7.38

......continued on the next page Tube Thorax Radiole Operculum

Internal External Number Number Peduncle Opercular Number Number

Species Length Width Length

diameter diameter left side right side length diameter of radii of spines minimum: 0.80 1.30 2.10 0.80 2.10 11.00 6.00 3.50 0.80 26 7