Austromegabalanus nigrescens ( Lamarck, 1818 )

Hosie, Andrew & Ahyong, Shane T., 2008, First records of the giant barnacles, Austromegabalanus nigrescens (Lamarck, 1818) and A. psittacus (Molina, 1782) (Cirripedia: Balanidae) from New Zealand, with a key to New Zealand Balanidae, Zootaxa 1674, pp. 59-64 : 60

Austromegabalanus nigrescens ( Lamarck, 1818)

( Fig. 1 , 2A–E )

Material examined. NIWA 34687–34714, 69 specimens, 4 ovigerous, Taharoa Ironsands Terminal, New Zealand, 38°10.53'S 174°41.35’E, 0–7 m, coll. C. Middelton et al., 23–24 May 2006. Australian Museum P21732, North West Cape, Western Austtralia, near Garden Island, coll. L Marsh.

Remarks. The series of A. nigrescens comprises 69 specimens collected from the Taharoa Ironsands Terminal, North Island, New Zealand. Taharoa Ironsands Terminal is an export port for iron sands extracted from coastal sand dunes in Taharoa, south of Kawhia Harbour. The sand is piped to a mooring situated in approximately 30 m of water almost 3 km from shore (38°10’32”S, 174°41’21”E) ( Figure 1 ). The specimens were collected from 27 sites, attached to the mooring and anchor lines, at 0–7 m depth. The specimens range from 4.5 mm to 68.3 mm basal diameter and 2.5 mm to 70.0 mm rostral height ( Figure 2A–E ), and accord well with published descriptions ( Pope 1945; Jones 1990). The Taharoa specimens are from an established population: at least three generations are present and four individuals were ovigerous. This species was most likely introduced via shipping at Taharoa.

Austromegabalanus nigrescens is native to open rocky shores of southern Australia, ranging from North West Cape (~ 21°47’S) in Western Australia (this study), to Southern Tasmania (~43° S) (Jones, 1990; Jones et al. 1990), and is a known biofouler, having been recorded from Copenhagen on vessel hulls ( Krüger 1927) and possibly the Ivory Coast (Gruvel 1903). The endemic Notomegabalanus decorus ( Darwin, 1854) , is also present, but relatively uncommon, at Taharoa terminal. The range of A. nigrescens within New Zealand is currently unknown but based on New Zealand’s latitudinal range, could be expected to include most of the New Zealand coastline. Notomegabalanus decorus and A. nigrescens occupy a similar habitat and encrusted individuals of the two species could be mistaken for each other by the casual observer.

Figures

FIGURE 1. Native distribution of Austromegabalanus nigrescens (grey) and A. psittacus (black). Inset: Known New

FIGURE 2. A – E, Austromegabalanus nigrescens, Taharoa Terminal, NIWA 34692. A. psittacus, Wellington Harbour, NIWA 25576. F – J, A, F, overall cluster. B, G, tergum, internal aspect. C, H, tergum, external aspect. D, I, scutum, internal aspect. E, J, scutum, external aspect. Scale A – E = 10 mm, F – J = 5 mm.