Invasion History
First Galapagos Record: 2018General Invasion History:
The hydroid of Egmundella humilis was described by Fraser (1936) from Sagami Bay, Japan. It has also been reported from Martinique, Seychelles, and Mauritania (Millard and Bouillon 1975; Vervoort 2006; Galea 2013; Calder et al. 2021). This hydroid is inconspicuous, and its global distribution and taxonomy is unclear.
Invasion History in the Galapagos:
In 2018, one colony was collected from Tiburon Matillo, San Cristobal Island, in the Galapagos archipelago. So far, it is the only record of this species from the Eastern Pacific. Its establishment in the Galapagos is unknown (Calder et al. 2021).
Invasion history elsewhere in the world:
Invasion history for Elsewhere in the World has not been summarized for this species.
Description
Egmundella humilis Fraser 1936 is a hydrozoan described from Japan. The hydroid was described from Sagami Bay, Japan. The medusa has not been described. Calder et al. (2021), lists the family as 'incerta sedis' (unknown), but WoRMS (2021) places it in Campanulariidae. The hydroid is inconspicuous and is roughly 0.3 to 1.0 mm tall (Galea 2013). This hydroid grows as small stolonal colonies with hydrothecae borne on wrinkled pedicels of varying lengths. The hydrothecae are tubular, 0.2–0.3 mm tall and are closed by opercules composed of multiple triangular flaps. Nematocysts are within nemathecae; bulbous structures budding from the stolons (Galea 2013; Calder et al. 2021).
Taxonomy
Taxonomic Tree
| Kingdom: | Animalia | |
| Phylum: | Cnidaria | |
| Class: | Hydrozoa | |
| Subclass: | Hydroidolina | |
| Order: | Leptothecata | |
| Family: | Campanulariidae | |
| Genus: | Egmundella | |
| Species: | humilis |
Synonyms
Potentially Misidentified Species
None
Ecology
General:
Egmundella humilis polyps grow from a creeping stolon attached to a hard substrate. The stolons presumably asexually produce gonophores, which then produce planula larvae. However, the gonophores have not been described (Calder et al. 2019). The planulae settle on suitable substrates and develop into a hydroid (Barnes 1983).
Food:
Zooplankton, small epibenthos
Consumers:
Competitors:
Trophic Status:
SusFed, CarnHabitats
| General Habitat | Rocky | None |
| General Habitat | Marinas & Docks | None |
| Tidal Range | Subtidal | None |
| Vertical Habitat | Epibenthic | None |
Life History
Tolerances and Life History Parameters
| Broad Temperature Range | 0 | Subtropical-Tropical |
| Broad Salinity Range | 0 | Polyhaline, Euhaline |
General Impacts
No impacts are known for native or introduced populations of Egmundella humilis.
Regional Distribution Map
| Bioregion | Region Name | Year | Invasion Status | Population Status |
|---|---|---|---|---|
| SEP-Z | 2018 | Def | Unk |
Occurrence Map
| OCC_ID | Author | Year | Date | Locality | Status | Latitude | Longitude |
|---|
References
Barnes, Robert D. (1983) Invertebrate Zoology, Saunders, Philadelphia. Pp. 883Calder, Dale R. and 8 authors (2021) Additions to the hydroids (Cnidaria, Hydrozoa) of marine fouling communities on the mainland of Ecuador and in the Galapagos Islands, Aquatic Invasions 16: 208-252
Fraser. C. McClean (1936) Some Japanese hydroids: Mostly new, Transactions of the Royal Society of Canada- Section V Biological Sciences 30: 49-53
Galea, Horia R. (2013) New additions to the shallow-water hydroids (Cnidaria: Hydrozoa) of the French Lesser Antilles: Martinique, Zootaxa 386(1): Published online
Millard, N. A. H.; Bouillon. J. (1975) Additional hydroids from the Seychelles, Annals of the South African Museum 69: 1-15
Vervoort, W. (2006) Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, The Netherlands [Anthoathecata, various families of Leptothecata and addenda]., Zoologische Mededelingen 80-1(11): 181-318
WoRMS Editorial Board (2021). 2021 World Register of Marine Species. https://www.marinespecies.org/