Hydroides dianthus (Verrill, 1873)

Serpula dianthus Verrill, 1873: 620 . Type locality: New Haven (Connecticut). Also collected from Great Egg Harbor (New Jersey) and Cape Cod (Massachusetts) , United States; intertidal to 15 m.

Eupomatus dianthus .— Holguín-Quiñones 1994: 234 (Socorro Island, Revillagigedo Archipelago, Mexican Pacific; indeterminable record).

Hydroides dianthus .— Bastida-Zavala & Salazar-Vallejo 2000b: 845, fig. 1m – u (southern Gulf of Mexico and Mexican Caribbean); Sun & Yang 2000: 120–121, fig. 2e–k (China); Bastida-Zavala & ten Hove 2002: 143–147, Figs 23A–M, 24A–k, 28 (east coast of United States, Gulf of Mexico and Mexican Caribbean; 0–28 m); Link et al. 2009: 1–6, Figs 1 a– g, 2 (Tokyo Bay, Japan, as NIS; 0.8 m, on PVC plates); Otani & Yamanishi 2010: 63–64, Figs 3 a–g (Osaka Bay, Japan, as NIS, seasonal change in densities; intertidal to 4 m, salinity 26.5–32.3‰, temperature 17.7–19.1°C, on concrete blocks); Ben-Eliahu & ten Hove 2011: 14–16 (Cyprus, 0.3 m, from ship propeller); Boltachova et al. 2011: 34–38 (Crimea, Black Sea); Sun et al. 2016a: poster (discussion as global invader or a complex of species).

Habitat. Intertidal to subtidal (28 m), on oysters, wooden pier and rocks (Bastida-Zavala & ten Hove 2002).

Distribution. East Coast of United States, Bermuda, Gulf of Mexico, Mexican Caribbean, Mediterranean, European Atlantic, Senegal (western Africa), Japan (Zibrowius 1971; Bastida-Zavala & ten Hove 2002; Link et al. 2009; Otani & Yamanishi 2010), China, Brazil and Black Sea (Sun & Yang 2000; Boltachova et al. 2011; Sun et al. 2016a). Holguín-Quiñones (1994: 234) recorded the species in an oceanic island in the Mexican Pacific, but their record is indeterminable (see remarks). Hydroides dianthus was long regarded as native to the tropical Western Atlantic; recently its American origin has been questioned and its status as a species complex, consisting of two cryptic species with high invasive potential, was evaluated, concluding that the recent invasions to Brazil and China were from Florida population, while the invasion to Crimea came from Mediterranean population (Sun et al. 2016a).

Remarks. The record of Hydroides dianthus by Holguín-Quiñones (1994) from Socorro Island (Mexican Pacific) is indeterminable because it lacks a description, figures, and the specimens were not deposited in a collection (Holguín-Quiñones, pers. comm. 2011). The species was not found in this study, but see Records not confirmed, below.