Galapagos Species Database

Taxon category: Accepted

Note: Obelia alternata was often misidentified as O. dichotoma due to underestimation of species diversity. Distinctive features include geniculate stems and short, annulated hydrothecal pedicels. It is recognized as a valid species, known only from the Galapagos Islands, and was collected from Isla San Cristóbal (Calder, et al. 2021). Syn.: Campanularia brasiliensis Meyen, 1834, Campanularia caulini Delle Chiaje, 1841, Campanularia cavolinii Deshayes & Edwards, 1836, Campanularia cheloniae Allman, 1888, Campanularia dichotoma (Linnaeus, 1758), Campanularia maior Meyen, 1834, Campanularia obtusidens Jäderholm, 1904, Eucope articulata A. Agassiz, 1865, Eucope parasitica A. Agassiz, 1865, Gonothyraea integra Fraser, 1940, Laomedea dichotoma (Linnaeus, 1758), Laomedea divaricata McCrady, 1859, Laomedea gracilis Dana, 1846, Laomedea sargassi Broch, 1913, Obelia Adelungi Hartlaub, 1884, Obelia alternata Fraser, 1938, Obelia angulosa Bale, 1888, Obelia arruensis Marktanner-Turneretscher, 1890, Obelia articulata (Agassiz, 1865), Obelia australis von Lendenfeld, 1885, Obelia biserialis Fraser, 1948, Obelia borealis Nutting, 1901, Obelia braziliensis (Meyen, 1834) (misspelling), Obelia cheloniae (Allman, 1888), Obelia chinensis Marktanner-Turneretscher, 1890, Obelia commissuralis McCrady, 1859, Obelia congdoni Hargitt, 1909, Obelia coughtreyi Bale, 1924,Obelia dubia Nutting, 1901, Obelia equilateralis Fraser, 1938, Obelia everta Hargitt, 1927, Obelia fragilis Calkins, 1899,Obelia gracilis Calkins, 1899, Obelia griffini Calkins, 1899, Obelia helgolandica Hartlaub, 1884, Obelia nigrocaulus Hilgendorf, 1898, Obelia nodosa Bale, 1924, Obelia obtusidens (Jäderholm, 1904), Obelia plicata Hincks, 1868, Obelia pygmaea Coughtrey, 1876, Obelia racemosa Fraser, 1941, Obelia rhunicola Billard, 1901, Obelia sinuosa Leloup, 1935, Obelia solowetzkiana Schydlwsky, 1902, Obelia surcularis Calkins, 1899, Obelia tenuis Fraser, 1938a, Obelia undotheca Stechow, 1923, Schizocladium ramosum Allman, 1871,Sertularia dichotoma Linnaeus, 1758 (Horton et al., 2021).

Origin: Cryptogenic

IUCN Red List Category: Not evaluated

Map of specimen collection localities or observation records for this species in our collections database.

Distribution: (O. tenuis) Galapagos Island in Isabela (Fraser, 1938). Santa Elena Bay, Cerros Islands and Galapagos Islands in Isabela I (Calder et al., 2003; Fraser, 1938; Fraser, 1948). North of Gogona Island and Galapagos Island in Isabela (Fraser, 1938). Galapagos Island in Fernandina, Española, Floreana, Isabela and Baltra (Calder et., 2003). Galapagos Island (Calder et al., 2021)

• Appeltans, W. Bouchet, P., Boxshall, G.A., Fauchald, K., Gordon, D.P., Hoeksema, B.W., Poore, G.C.B., van Soest, R.W.M., Stöhr, S., Walter, T.C., Costello, M.J. (eds.) (2010) World Register of Marine Species (WoRMS). Available online at http://www.marinespecies.org.
• Banks, S. Vera, M. & Chiriboga, A. (2009) Establishing Reference Points to Assess Long-Term Change in Zooxanthellate Coral Communities of the Northern Galapagos Coral Reefs. J. Sci. Conserv. in the Galapagos Islands, p. 43-64.
• Calder, D.R. Carlton, J. T., Larson, K., Mallinson, J. J., Choong, H. H. C., Keith, I., & Ruiz, G. M (2019) Hydroids (Cnidaria, Hydrozoa) from marine fouling assemblages in the Galápagos Islands, Ecuador Aquatic Invasions (2019) Volume 14, Issue 1: 21–58
• Calder, D.R. Mallinson, J.J., Collins, K. & Hickman, C.P. (2003) Additions to the Hydroids (Cnidaria) of the Galapagos, with a List of Species Reported from the Islands. J. Nat. Hist. 37:1173-1218.
• Calder, D.R. Carlton, J. T., Keith, I., Larson, K., McCann, L., Geller, J., Wheelock, M., Choong, H. H. C., & Ruiz, G. M. (2021) Additions to the hydroids (Cnidaria, hydrozoa) of marine fouling communities on the mainland of ecuador and in the galapagos islands Aquatic Invasions, 16(2), 208–252. https://doi.org/10.3391/ai.2021.16.2.02
• Carlton, J. T. Keith, I., & Ruiz, G. M. (2019) Assessing marine bioinvasions in the Galápagos islands: Implications for conservation biology and marine protected areas. Aquatic Invasions, 14(1), 1–20. https://doi.org/10.3391/ai.2019.14.1.01
• Fraser, C. M. (1938) Hydroids of the 1932, 1933, 1935 and 1938 Allan Hancock Pacific Expeditions In Allan Hancock Pacific Expeditions (pp. 1–152)
• Fraser, C.M. (1939) Distribution of the hydroids in the collections of the Allan Hancock Expeditions. Fraser, M. (1939). Distribution of the hydroids in the collections of the Allan Hancock Expeditions. In Allan Hancock Pacific Expeditions. (Vol. 4, pp. 155–178).
• Freaser, McLean (1948) Hydroids of the Allan Hancock Pacific Expeditions since March, 1938. Fraser, M. (1948). Hydroids of the Allan Hancock Pacific Expeditions since March, 1938. In Allan Hancock Pacific Expeditions. (5th ed., pp. 179–334).
• Hickman, C.P. Jr. (2008) A field guide to corals and other radiates of Galápagos. Sugar Spring Press, Lexington, Virginia, 162 pp.
• Horton, T. Horton, T., Kroh, A., Ahyong, S., Bailly, N., Boyko, C. B., Brandão, S. N., Gofas, S., Hooper, J. N. A., Hernandez, F., Holovachov, O., Mees, J., Molodtsova, T. N., Paulay, G., Decock, W., Dekeyzer, S., Poffyn, G., Vandepitte, L., Vanhoorne, B., Adlard, R., ... Zhao, Z. (2021) World Register of Marine Species. Available from https://www.marinespecies.org at VLIZ.