Salacia tetracythara Lamouroux 1816

Salacia tetracythara Lamouroux, 1816

Fig. 9h, i

Salacia tetracythara Lamouroux, 1816: 214, pl. 6 fig. 3a, B, C [correct original spelling].

Salacia tetracyttara Lamouroux, 1816: 553 [incorrect original spelling].

Thuiaria fenestrata.— Nutting, 1905: 950.

Type locality. Australasia? (Lamouroux 1816).

Voucher material. Lisianski Island, 01.x.2002, two colonies, to 3.4 cm high, one with gonothecae, coll. A. Faucci, ROMIZ B5429.— Pearl & Hermes Atoll, 28.ix.2002, three colonies, to 5.5 cm high, without gonothecae, coll. A. Faucci, ROMIZ B5430.— Laysan Island, 18.ix.2002, one colony, 1.5 cm high, without gonothecae, coll. A. Faucci, ROMIZ B5431.— Kure Atoll, detached, 25.ix.2002, one colony, 2.3 cm high, without gonothecae, coll. A. Faucci, ROMIZ B5432.— Laysan Island, 17.ix.2002, two colonies, to 5.2 cm high, without gonothecae, coll. A. Faucci, ROMIZ B5433.

Remarks. As shown in the synonymy list above, the specific name of this species was spelled two different ways (as tetracythara and tetracyttara) in the original work by Lamouroux (1816). Rees & Vervoort (1987: 103), Acting as First Revisers (ICZN 1999, Art. 24.2.3), selected tetracythara as correct. Cornelius (1975: 381) noted that Salacia tetracythara Lamouroux, 1816 is the type species, by monotypy, of the genus Salacia Lamouroux, 1816. He provided a historical account of the synonymy of the genus and species, and noted that its type was destroyed during World War II. Billard (1909b) had earlier examined the type and found that it corresponded well with Thuiaria fenestrata Bale, 1884 from Australia. The two are now widely considered conspecific, and the account of Bale (1884) facilitates identification of the species. Also taken to be a synonym is Calyptothujaria opposita von Campenhausen, 1896 from Ternate, Indonesia.

Salacia and Thuiaria Fleming, 1828 have at times been regarded as congeners (Stechow 1922, 1923c; Rees & Thursfield 1965; Cornelius 1979), although they are currently held to be distinct (Cornelius 1995b; Hirohito 1995; Bouillon et al. 2006; Song 2019). A key difference in terms of morphology is the presence of an abcauline diverticulum or caecum (Millard 1975, fig. 81A) in Thuiaria and its absence in Salacia. A molecular analysis of S. tetracythara, needed to clarify relationships of Salacia, have yet to be undertaken. Sertularia desmoides Torrey 1902, subjectively assigned at present to the same genus, has been shown to be genetically distant from Thuiaria thuja (Moura et al. 2011; Maronna et al. 2016; Song 2019), the type species of Thuiaria.

Salacia tetracythara is widely distributed across the tropical and subtropical Indo-Pacific region (Rees & Vervoort 1987), and it has recently been reported from Brazil in the Atlantic Ocean (Mendonça et al. 2021). The hydranth and modified tentacles of this hydroid were studied and described by Gravier-Bonnet (2008).

Reported Distribution. Hawaiian archipelago. Laysan Island: north of the island, 20 fathoms (37 m) (Nutting 1905, as Thuiaria fenestrata).—Maui: NE of the island, 14 fathoms (26 m) (Nutting 1905, as T. fenestrata ).

Elsewhere. Tropical and subtropical Indo-Pacific, from the Mozambique Channel and the Gulf of Aden to Hawaii (Lamouroux 1816; Billard 1909b, as Thuiaria tetracythara; Pennycuik 1959; Mammen 1965; Rees & Vervoort 1987; Gibbons & Ryland 1989; Hirohito 1995; Watson 2000; Schuchert 2003; Gravier-Bonnet 2007, 2008; Di Camillo et al. 2008; Gravier-Bonnet & Bourmaud 2012; Preker & Lawn 2012; Song 2019).—Atlantic Ocean, Brazil (Mendonça et al. 2021).