Nemertesia simplex ( Allman, 1877 )

Calder, Dale R., 2013, Some shallow-water hydroids (Cnidaria: Hydrozoa) from the central east coast of Florida, USA, Zootaxa 3648 (1), pp. 1-72 : 36-37

Nemertesia simplex ( Allman, 1877)

Fig. 10b, c

Antennularia simplex Allman, 1877: 34 , pl. 21, figs. 1, 2.

Type locality. USA: Florida, off Alligator Reef , 86 fathoms (157 m) ( Allman 1877: 34) .

Voucher material. Hoskin Reef off Vero Beach, 27°41.4’N, 79°59.1’W, 65 m, 02.vi.1982, Johnson-Sea-Link I, JSL 1197, one colony, up to 9 cm high, without gonophores, 3.7 cm high, without gonothecae, coll. C. Hoskin, ROMIZ B1121 .— Off Sebastian Inlet, 27°47.2’N, 79°57.2’W, 110– 99 m, 28.vi.1978, 10- foot try net, one colony, up to 46 cm high, with gonophores, coll. J. Miller, ROMIZ B1122 .

Remarks. Nemertesia simplex ( Allman, 1877) is poorly known. The only original records of the species other than that of Allman (1877), from the Alligator Reef area in the Straits of Florida, are those of Nutting (1900). He reported N. simplex in collections taken off Cape Henry, Virginia, Cape Hatteras, North Carolina, and Havana, Cuba, during Albatross cruises, and from the Pourtalès Plateau (Straits of Florida) in material from the 1893 Bahamas Expedition of the State University of Iowa. Moreover, the only illustrations of the species prior to now are the two of Allman (1877). Nutting included a copy of Allman’s magnified figure of the species in his monograph on plumularioids but gave no illustrations of his own material. The present record from the east coast of Florida falls within the stated geographic and bathymetric range (48–373 fathoms = 88–682 m) of the species.

Characters differentiating N. simplex from its congeners were tabulated by Ramil & Vervoort (2006). They upheld opinions of Allman (1877) and Nutting (1900) that it has affinities with N. ramosa ( Lamarck, 1816) . Both have monomeric or mostly monomeric hydrocladia. Morphological differences distinguishing Nemertesia simplex from N. ramosa include the following: (1) the hydrocaulus is monosiphonic and unbranched or only slightly branched rather than polysiphonic and much branched; (2) hydrothecal margins tend to slope at an oblique angle to the axis of the hydrocladium rather than being perpendicular to it. Gonothecae, of the usual type in this genus ( Ramil & Vervoort 2006), are quite small, ovoid, and with an oblique aperture ( Nutting 1900). They arise from apophyses of the hydrocladia.

Reported distribution. Atlantic coast of Florida. First record.

Western Atlantic. Offshore waters of Virginia to the Gulf of Mexico ( Nutting 1900) .

Figures

FIGURE 10. a, Dentitheca dendritica: part of hydrocladium with two hydrothecae, ROMIZ B1130, scale equals 0.10 mm. b, Nemertesia simplex: apophysis and basal part of hydrocladium, ROMIZ B1121, scale equals 0.20 mm. c, Nemertesia simplex: part of hydrocladium with hydrotheca, ROMIZ B1121, scale equals 0.10 mm. d, Plumularia floridana: part of hydrocaulus with basal parts of two hydrocladia, and three hydrothecae, ROMIZ B1080, scale equals 0.25 mm. e, Plumularia setacea: part of hydrocaulus with basal parts of two hydrocladia, a female gonotheca, and a hydrotheca, ROMIZ B1111, scale equals 0.20 mm. f, Plumularia strictocarpa: part of hydrocaulus with basal parts of two hydrocladia, and three hydrothecae, ROMIZ B3971, scale equals 0.20 mm.