Tridentata turbinata ( Lamouroux, 1816 )

Castro Mendonça, Luana M., Parisotto Guimarães, Carmen R. & Haddad, Maria A., 2022, Taxonomy and diversity of hydroids (Cnidaria: Hydrozoa) of Sergipe, Northeast Brazil, Zoologia (e 21032) 39, pp. 1-65 : 55-56

Tridentata turbinata ( Lamouroux, 1816)

Fig. 22G–H

Synonyms available from: Calder (1991), Medel and Vervoort (1998) and Calder (2008).

Dynamena turbinata Lamouroux, 1816: 180 .

Sertularia turbinata – Migotto, 1996: 78, fig. 14F, G.

Geminella ceramensis – Vannucci Mendes, 1946: 570.

Description: Colonies erect, up to 15.2 mm high, unbranched, arising from a creeping hydrorhiza. Stem ahydrothecate at the base, internode separated by an oblique hinge, the others by slightly oblique nodes. Long internodes each with a pair of opposite hydrothecae. Hydrothecae short, 0.15–0.22 mm high, 0.13–0.15 mm maximum diameter, inflated at halfway their basal portion, adnate to the stem less than half their height, free portion curving outwards. Abcauline wall is almost straight at the half basal portion, and slightly concave at the curvature. Adcauline wall convex in the adnate portion and straight to perpendicular in the free portion. In some hydrothecae, it is possible to see a crossed line of perisarc at the curvature of the adcauline wall. A perisarc thickening horseshoe shape is visible at the curvature of the abcauline wall, projecting toward the center of the hydrothecae. Margin hydrothecal with three cusps, two wide laterals, and one small median adcauline. Operculum with two valves, one wide and one small. Nematocysts microbasic mastigophores? undischarged (8.2–10.1 × 2.4–3 µm), in hydranth and coenosarc.

Material examined: PCS – few infertile colonies from the rainy season. CZUFS CNI-00221.

Stations: PCS – 5, 12, 15.

Bottom: gravel and sand.

Distribution: The species has been recorded as Sertularia turbinata and Tridentata turbinata in Brazil. Brazil – Pernambuco ( Calder and Maÿal 1998), Fernando de Noronha ( Amaral et al. 2009), Espírito Santo ( Grohmann et al. 1997, 2003), Rio de Janeiro ( Nogueira et al. 1997, Grohmann et al. 2003), São Paulo ( Oliveira et al. 2006, Cunha and Jacobucci 2010, Oliveira and Marques 2011, Silveira and Morandini 2011, Marques et al. 2013), Paraná (Maria A. Haddad unpub. data), and Santa Catarina ( Miranda et al. 2011, Bouzon et al. 2012). World distribution – circumglobal from tropical to subtropical regions ( Millard 1975).

Taxonomic remarks: According to Calder (2019) this species has long been misassigned to a non-monophyletic genus Sertularia Linnaeus, 1758 instead of Tridentata Stechow, 1920 .

Remarks: All colonies were on algae.

Figures

Figure 22. (A) Salacia tetracythara: general view of a stem showing few hydrocladia and hydrothecae; (B) Tridentata loculosa: detail of the stem with two hydrocladia and few hydrothecae; (C-E) Tridentata marginata: (C) general view of a stem with two gonothecae (red arrows); (D) detail of a stem with few hydrocladia and hydrothecae; (E) detail of one gonotheca; (F, I) Tridentata rugosissima: (F) detail of one pair of hydrothecae; (I) general view of a stem with several hydrothecae; (G-H) Tridentata turbinata: (G) detail of one pair of hydrothecae; (H) detail of a stem with hydrothecae.