Halopteris alternata ( Nutting 1900 )

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, Zootaxa 4758 (1), pp. 127-140 : 131

Halopteris alternata ( Nutting 1900)

Fig. 2

Plumularia alternata Nutting, 1900: 62 , pl. 4, figs. 1, 2.

Halopteris alternata Schuchert 1997: 42 , fig. 14.

Type locality. Bahamas: Barracuda Rocks ( Nutting 1900: 62) .

Voucher material. 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.

Description. 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.

Reported distribution. 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 et al. 2001). Brazil ( Oliveira et al. 2016).

Figures

FIGURE 2. Halopteris alternata Hydrocaulus and hydrocladium fragments. A. Upper axillary nematotheca. B. Oblique internode. C. Intersegment medium nematotheca. D. First segment of the lateral apophyses. E. Male gonotheca. F. Hydrocladium with adcauline wall of hydrothecae. G. Hydrothecal margin. H. Abcauline wall of hydrothecae. I. Mobile lateral nematotheca. J. Medium intersegment nematotheca in the hydrocladium.