Tridentata marginata ( Kirchenpauer, 1864 )

Gil, Marta & Ramil, Fran, 2025, Hydroids (Cnidaria, Hydrozoa) from Guinea Bissau, Zootaxa 5577 (1), pp. 1-89 : 54-55

Tridentata marginata ( Kirchenpauer, 1864)

( Fig. 9B–D )

Dynamena marginata Kirchenpauer, 1864: 13 , fig. 8.

Tridentata marginata : Calder, 1991: 107–109, figs 56, 57.— Calder, 2013: 31–33 , fig. 9E–F.

Sertularia marginata : Leloup, 1939: 422, fig. 4.— Buchanan, 1957: 367.—Millard, 1975: 311–312, fig. 99A–D.— Migotto, 1996: 73–75, fig. 14A–C.— Medel & Vervoort, 1998: 66–70, figs 20C, 22.—Galea, 2015: 12, fig. 3Q–R.

Sertularia versluysi : Ritchie, 1907: 505–507, text–fig. 144, pl. XXIV figs 2–6.

Material examined. BISSAU-0810, stn BS191, 10º18'25"– 10º19'20"N, 16º08'47"– 16º08'47"W, 24–25 m, 3-XI-2008: 85 colonies without gonothecae, 8–107 mm high, of which six growing on Diphasia digitalis , two on Idiellana pristis , two on worm tubes, two on a bryozoan and one on a bivalve.

BISSAU-0810, stn BS192, 10º19'30"– 10º20'15"N, 16º10'27"– 16º10'59"W, 24 m, 3-XI-2008: five colonies without gonothecae, 40–155 mm high, substrate unknown.

BISSAU-0810, stn BS193, 10º21'13"– 10º21'51"N, 16º10'17"– 16º10'56"W, 20–21 m, 3-XI-2008: one colony without gonothecae, 96 mm high, substrate unknown.

BISSAU-0810, stn BS194, 10º21'59"– 10º22'36"N, 16º13'23"– 16º14'03"W, 21–24 m, 3-XI-2008: four colonies without gonothecae, 55–75 mm high, substrate unknown.

BISSAU-0810, stn BS195, 10º22'44"– 10º23'22"N, 16º15'37"– 16º16'18"W, 29 m, 3-XI-2008: six colonies (five with gonothecae), 27–130 mm high, substrate unknown.

BISSAU-0810, stn BS199, 10º16'49"– 10º17'29"N, 16º22'15"– 16º22'49"W, 65–70 m, 4-XI-2008: one colony without gonothecae, 81 mm high, substrate unknown.

Remarks. Differences between T. marginata and Tridentata turbinata ( Lamouroux, 1816) were pointed out by Calder (2013), and also discussed by Gil & Ramil (2023b).

Our finding represents the first record of this species for Guinea-Bissau.

Biology. This species has been found growing on algae and rocks ( Migotto 1996), stranded Thalassia sp. , shipwrecks ( Calder 1991), Zostera leaves ( Medel & Vervoort 1998) and stranded Sargassum sp. ( Calder 2013). In the northern hemisphere, fertile colonies were found in May, June, July, October and November ( Medel & Vervoort 1998; Calder 2013), while in the southern hemisphere gonothecae have been found throughout the year ( Migotto 1998).

In our material colonies were found growing on hydroids, polychaetes, bryozoans and bivalves. Gonothecae were found in November.

Distribution. Tridentata marginata is a circumtropical species ( Migotto 1996; Vervoort & Watson 2003). In West Africa, it has been recorded from Morocco ( Medel & Vervoort 1998), Mauritania ( Billard 1906a, as S. versluysi ; Medel & Vervoort 1998), the Cape Verde Islands ( Ritchie 1907, as S. versluysi ; Medel & Vervoort 1998), Ghana ( Buchanan 1957) and Congo ( Leloup 1939). Its bathymetric distribution ranges from 0 (Millard 1975) to 90 m ( Grohmann et al. 2003).

Our material was collected at depths between 20–70 m.

Figures

FIGURE 9.A. Tridentata loculosa (Busk, 1852) (stn BS199), portion of stem. B–D. Tridentata marginata (Kirchenpauer, 1864) (stn BS195); portion of colony (B); gonothecae (C–D). E. Tridentata rugosissima (Thornely, 1904) (stn BS193), portion of stem. F. Tridentata turbinata (Lamouroux, 1816) (stn BS191), portion of stem. Scales: a–f, 0.5 mm.