Gelidium pusillum (Stackhouse) Le Jolis 1863

Publication Details
Gelidium pusillum (Stackhouse) Le Jolis 1863: 139

Published in: Le Jolis, A. (1863). Liste des algues marines de Cherbourg. Mémoires de la Société Impériale des Sciences Naturelles de Cherbourg 10: 5-168, pls I-VI [1-6].

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Type Species
The type species (holotype) of the genus Gelidium is Gelidium corneum (Hudson) J.V.Lamouroux.

Status of Name
This name is of an entity that is currently accepted taxonomically.

Basionym
Fucus pusillus Stackhouse

Type Information
Type locality: Sidmouth, Devon, England; (Dixon & Irvine 1977: 129) Lectotype (provisional): BM; (Dixon & Irvine 1977: 139)

Origin of Species Name
Adjective (Latin), very small (Stearn 1983).

General Environment
This is a marine species.

Description
Cartilaginous, purplish or blackish red, turf-forming, 2-10 mm high, arising from an extensive creeping base and incorporating shell debris and small molluscs. Erect fronds flattened and leaf-like and 0.5-2 mm broad.

Habitat
On rock in upper intertidal forming extensive mat-like growths below Pelvetia canaliculata, particularly on vertical or near-vertical surfaces. Sometimes associated with Catenella caespitosa and Rhodothamniella purpurea. Widely distributed, common.

Key Characteristics
Turf formation in the upper intertidal, blackish-red colour when slightly dry, and extensive rhizoids.

Similar Species
Catenella caespitosa also forms turf- or mat-like extensions but is softer has has the appearance of small cocktail sausages.

Created: 30 March 1996 by M.D. Guiry.

Last updated: 03 June 2021

Verification of Data
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Taxonomic notes
South & Skelton (2003) note that confusion probably occurs between G. pusillum and G. samoense (Santelices et al . 2003). John et al. (2004) cite Gelidium pusillum var. pulvinatum (C. Agardh) Feldmann, G. pulchellum (Turner) Kützing, G. pulvinatum (Kützing) Thuret ex Bornet and G. reptans (Suhr) Kylin as synonyms of this species, but see Fredriksen, Guiry & Rueness (1994) in relation to the separateness of G. pulchellum. - (11 May 2006) - G.M. Guiry
The occurrence of this upper intertidal species world-wide needs investigation. The name may only be applicable to upper-intertidal plants in damp crevices and under fucoids in the north-eastern Atlantic, and even then species limits are not clear. - (17 August 2006) - G.M. Guiry
Lipkin & Silva (2002: 9, 10) note that Gelidium crinale and G. pusillum are traditionally recognized as two distinct species (Feldmann & Hamel 1936: 107). They were merged by Dixon & Irvine (1977: 126), based on sequential field observations of marked plants in Britain and more detailed understanding of growth and behaviour. Lipkin & Silva (2002), while having no reason to doubt the validity of this conclusion, note that specimens of 'G. crinale' from the Red Sea and many other parts of the world (Indian Ocean, see Silva et al. 1996: 137) are not conspecific with G. pusillum and they follow traditional, albeit faulty, species concepts in dealing with Red Sea specimens. Womersley & Guiry(1994: 133) note that the type of G. crinale and Australian specimens appear to be distinct from the type of G. pusillum - (31 May 2010) - G.M. Guiry

Habitat note
Epilithic in the midlittoral, lower littoral and occasionally in the upper sublittoral (Dixon & Irvine 1977: 129). Cosmopolitan; on rock, ca. 1 m depth, on dendroid crustose coralline (Lipkin & Silva 2002: 10). - (31 May 2010) - G.M. Guiry

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Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 03 June 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 28 March 2025

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