Halopteris alternata

Abstract

<i>Halopteris alternata</i> (Nutting 1900) <p>Fig. 2</p> <p> <i>Plumularia alternata</i> Nutting, 1900: 62, pl. 4, figs. 1, 2.</p> <p> <i>Halopteris alternata</i> Schuchert 1997: 42, fig. 14.</p> <p> <b>Type locality.</b> Bahamas: Barracuda Rocks (Nutting 1900: 62).</p> <p> <b>Voucher material.</b> Reef patches of Santa Marta, Magdalena, Colombia. 53 feet (16 m), October 2015, SCUBA. Apical fragment of a colony 2 cm high, without hydrorhiza and with a male gonotheca.</p> <p> <b>Description.</b> Segmented obliquely monosiphonic hydrocaulus with alternating hydrocladium, each of the main segments of the hydrocaulus and hydrocladium presents a main hydrothecae and three or four nematothecas: two laterals, one inferior and one upper axillary to the hydrothecae present in the distal part of the colony. The intersegments have a nematotheca in the middle part. Each hydrocladium has lateral apophyses with a first short, square segment devoid of nematothecas, the second segment is elongated, and with a nematotheca in the middle zone, the rest of the hydrocladium has homomerous segmentation. As in the hydrocaulus, the intersegments have a nematotheca in the middle part. The hydrothecae has a cup shape, the adcauline and abcauline wall are straight laterally, and it joins the hydrocaulus from half to three quarters of the adcauline wall. The middle-lower nematotheca is immobile and the margin does not exceed the base of the hydrothecae, the lateral nematotheca is cone-shaped and emerges from a short and mobile pedicel, the margin is smooth and is not everted. The nematothecas of the intersegments are similar to the mid-lower, but are mobile and have a longer adcauline wall. The axillary nematotheca is the same as the rest of nematothecas. All the nematothecas present two cameras (bitalamic). The male gonotheca emerges from the hydrocaulus through a pedicel of a segment and presents an oblong shape.</p> <p> <b>Reported distribution.</b> The Gulf of Mexico (Calder & Cairns 2009). Unites States in Florida (Calder 2013). The Caribbean Sea (Galea 2008; Calder & Kirkendale 2005). Eastern Atlantic (Ansín Agís <i>et al.</i> 2001). Brazil (Oliveira <i>et al.</i> 2016).</p>Published as part of <i>Torres-Rodríguez, Javier, Ortiz-Oyola, Daniel, Puentes-Sayo, Alejandra, Lecompte, Orlando P. & Jauregui, Aminta, 2020, Genetic and morphologic identities of hydrozoans (Cnidaria, Hydrozoa) from reef patches of Santa Marta, Colombian Caribbean, pp. 127-140 in Zootaxa 4758 (1)</i> on page 131, DOI: 10.11646/zootaxa.4758.1.5, <a href="http://zenodo.org/record/3731737">http://zenodo.org/record/3731737</a&gt