Halecium cf. beanii (Johnston, 1838),

Galea, Horia R., 2010, Notes on a small collection of thecate hydroids (Cnidaria: Hydrozoa) from Tristan da Cunha, south Atlantic, Zootaxa 2336, pp. 1-18: 4-5

publication ID

http://doi.org/ 10.5281/zenodo.205235

persistent identifier

http://treatment.plazi.org/id/03E7237E-FFF0-4D55-FF77-1A80F61EFF44

treatment provided by

Plazi

scientific name

Halecium cf. beanii (Johnston, 1838)
status

 

Halecium cf. beanii (Johnston, 1838) 

( fig. 3View FIGURE 3 D)

Thoa beanii Johnston, 1838: 120  , pl. 7 figs 1–2View FIGURE 1View FIGURE 2.

Halecium beanii  – Schuchert, 2005: 615, figs 5View FIGURE 5 –6.

Material examined. Stn. T10, 15.ii.2005: one sterile colony, 5.5 cm high, with polysiphonic stem ( NHM 2009.17).

Remarks. The examined specimen is provisionally assigned to Johnston’s (1838) species on the account of its polysiphonic, irregularly branched stem. However, additional fertile female specimens are necessary to validate the present identification.

Millard (1975) observed both H. beanii  and H. halecinum (Linnaeus, 1758)  in South Africa, the closest location to Tristan da Cunha. She also warned about the impossibility of proper identification of these species in the absence of female gonothecae. On the other hand, Cornelius (1995a) showed that Linnaeus’ (1758) species always forms regularly pinnate colonies, while the stems of H. beanii  are “imperfectly pinnate, shrubby, varied in appearance”, a conclusion partly shared by Schuchert (2005), who showed several exceptions.

Although Millard (1975) did not discuss any morphological peculiarities in the female gonothecae of H. beanii  from South Africa, Schuchert (2005) showed several important differences (polygonal cross-section, 1. Torrey’s (1902) species has sessile primary hydrothecae, not terminal on branches, as illustrated by Jäderholm (1920).

increased number of eggs), rendering it distinct from the European population.

Distribution. Cosmopolitan, penetrating well into the Arctic Ocean and the coasts of Patagonia, but not into the Antarctic (Medel & Vervoort 2000). This is the first record of this species for Tristan da Cunha.

NHM

University of Nottingham

Kingdom

Animalia

Phylum

Cnidaria

Class

Hydrozoa

Order

Leptothecata

Family

Haleciidae

Genus

Halecium

Loc

Halecium cf. beanii (Johnston, 1838)

Galea, Horia R. 2010
2010
Loc

Thoa beanii

Johnston 1838: 120
1838