Diphasia digitalis ( Busk, 1852 )

Calder, Dale R., 2013, Some shallow-water hydroids (Cnidaria: Hydrozoa) from the central east coast of Florida, USA, Zootaxa 3648 (1), pp. 1-72 : 24-26

Diphasia digitalis ( Busk, 1852)

Fig. 8a

Sertularia digitalis Busk, 1852: 393 .

Type locality. Australia: Torres Strait , Prince of Wales Channel ( Busk 1852: 393) .

Voucher material. West Palm Beach, on reef seaward of the Breakers Hotel, 45 feet (13.7 m), together with Halopteris carinata , January 1991, SCUBA, one colony, 2.5 cm high, without gonophores, coll. P. Humann, ROMIZ B3964.

Remarks. Diphasia digitalis ( Busk, 1852) was first reported in the western Atlantic by Allman (1877) from Key West, Florida, although he assigned it to a new genus and species ( Desmoscyphus longitheca ). Soon after, Allman (1888) reported it from Bahia, Brazil, but described it as a new species ( Desmoscyphus acanthocarpus ). Nutting (1904) concluded that Desmoscyphus longitheca Allman, 1877 and D. acanthocarpus Allman, 1888 were identical after examining types of the two nominal species, and assigned both to the synonymy of Diphasia digitalis .

Bale (1884: 101) noted that colonies of this species appear “dark gray, almost black.” Others have described them as dark brown (e.g., Morri et al. 2009). The colouration is due to blackish pigment granules in epidermal layers of the coenosarc ( Schuchert 2003). Material examined here, in fair condition, had obvious black pigment granules in the coenosarc.

The known range of Diphasia digitalis in the western Atlantic is extended slightly to the north, having been reported earlier from the Florida Keys ( Fraser 1944) .

Reported distribution. Atlantic coast of Florida. First record.

Western Atlantic. West Palm Beach area, Florida (reported herein) to Brazil (Oliveira et al. submitted), and including the Gulf of Mexico ( Calder & Cairns 2009) and the Caribbean Sea ( Vervoort 1968).

Elsewhere. Circumglobal in tropical and subtropical waters ( Millard 1975; Schuchert 2003).

Figures

FIGURE 8. a, Diphasia digitalis: part of a hydrocladium with hydrothecal pairs, ROMIZ B3964, scale equals 0.25 mm. b, Dynamena crisioides: part of hydrocaulus with basal part of a hydrocladium and hydrothecae, ROMIZ B3965, scale equals 0.25 mm. c, Dynamena dalmasi: part of hydrocaulus with two hydrothecal pairs, ROMIZ B1081, scale equals 0.25 mm. d, Dynamena disticha: part of hydrocaulus with two hydrothecal pairs, ROMIZ B3966, scale equals 0.20 mm. e, Pasya quadridentata: part of hydrocaulus with three hydrothecal pairs, ROMIZ B1085, scale equals 0.25 mm. f, Pasya quadridentata: gonotheca, ROMIZ B1085, scale equals 0.25 mm. g, Salacia desmoides: part of hydrocaulus with two hydrothecal pairs, ROMIZ B3967, scale equals 0.25 mm. h, Sertularella areyi: part of hydrocaulus with two hydrothecae, ROMIZ B1135, scale equals 0.5 mm. i, Sertularella conica: part of hydrocaulus with three hydrothecae, ROMIZ B1087, scale equals 0.25 mm.