Idiellana pristis ( Lamouroux, 1816 )

Gil, Marta & Ramil, Fran, 2025, Hydroids (Cnidaria, Hydrozoa) from Guinea Bissau, Zootaxa 5577 (1), pp. 1-89 : 51-52

Idiellana pristis ( Lamouroux, 1816)

( Fig. 8D–F )

Idia pristis Lamouroux, 1816: 199–200 , pl. 5 fig. 5. Idiellana pristis : Millard, 1975: 269–270, fig. 88A–E.— Vervoort, 1993: 188.— Hirohito, 1995: 178–180, fig. 58.— Migotto, 1996: 65–67, figs 12H–I.— Watson, 2000: 19–20, fig. 14A–E.— Schuchert, 2003: 175–176, fig. 32.

Material examined. BISSAU-0810, stn BS189, 10º19'32"– 10º18'42"N, 15º30'40"– 15º31'04"W, 22–28 m, 3-XI-2008: eight colonies with gonothecae, 46–80 mm high, unknown substrate.

BISSAU-0810, stn BS191, 10º18'25"– 10º19'20"N, 16º08'47"– 16º08'47"W, 24–25 m, 3-XI-2008: 1427 colonies (52 with gonothecae), 14–99 mm high, of which 112 growing on bryozoans, 18 on Diphasia digitalis , 10 on crustaceans, six on worm tubes, five on bivalves, one on Eudendrium capillare , one on Tridentata loculosa , one on Tridentata marginata , one on Tridentata turbinata and one on Thyroscyphus marginatus .

BISSAU-0810, stn BS192, 10º19'30"– 10º20'15"N, 16º10'27"– 16º10'59"W, 24 m, 3-XI-2008: 75 colonies (one with gonotheca), 17–100 mm high, of which two growing on bivalves, one on a worm tube and one on Diphasia digitalis .

BISSAU-0810, stn BS193, 10º21'13"– 10º21'51"N, 16º10'17"– 16º10'56"W, 20–21 m, 3-XI-2008: 15 colonies without gonothecae, 17–100 mm high, of which one growing on a bivalve and one on a bryozoan.

BISSAU-0810, stn BS194, 10º21'59"– 10º22'36"N, 16º13'23"– 16º14'03"W, 21–24 m, 3-XI-2008: 55 colonies (27 with gonothecae), 17–111 mm high, of which one growing on a worm tube and another one on a crustacean.

BISSAU-0810, stn BS195, 10º22'44"– 10º23'22"N, 16º15'37"– 16º16'18"W, 29 m, 3-XI-2008: 59 colonies (52 with gonothecae), 18–170 mm high, of which one growing on a crustacean.

BISSAU-0810, stn BS199, 10º16'49"– 10º17'29"N, 16º22'15"– 16º22'49"W, 65–70 m, 4-XI-2008: one colony without gonothecae, 27 mm high, unknown substrate.

Remarks. In one colony from station BS191 and two colonies from station BS194, we observed the phenomenon of auto-epizoism, as described by Millard (1973) in other hydroids. Idiellana pristis is a well-known species in West Africa, and needs no further discussion.

Biology. This species has been found growing on rocks ( Migotto 1996), dead coral and other invertebrates ( Vervoort 1993; Watson 2000). In the northern hemisphere, gonothecae were found in January, February, May and July–December, while in the southern hemisphere fertile colonies were found in February, April, May, July, August and November ( Gil & Ramil 2023b).

In our material, colonies were found growing on several hydroid species, bryozoans, bivalves, worm tubes and crustaceans. Gonothecae were found in November.

Distribution. Idiellana pristis is a circumtropical species ( Watson 2000; Schuchert 2003) in shallow waters, whose distribution in West Africa has been recently revised by Gil & Ramil (2023b). Its bathymetric distribution ranges from 0 (Millard 1975) to 150 m ( Vervoort 1993).

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

Genus Tridentata Stechow, 1920

Figures

FIGURE 8. A. Sertularella polyzonias (Linnaeus, 1758) (stn BS157), portion of colony. B. Sertularella undulitheca Vervoort, 1959 (stn BS192), portion of hydrocladium. C. Amphisbetia distans (Lamouroux, 1816) (stn BS192), portion of stem. D–F. Idiellana pristis (Lamouroux, 1816) (stn BS191); portion of hydrocladium (D); gonothecae (E–F). Scales: a–f, 0.5 mm.