Obelia longissima

Obelia longissima is a species of colonial hydroid, a type of invertebrate animal belonging to the phylum Cnidaria. It is commonly found in marine environments, often forming intricate and delicate colonies that can reach considerable lengths.

Description & Characteristics

Obelia longissima colonies consist of numerous individual polyps, each specialized for a specific function. The polyps are connected by a network of stolons, forming a branching structure known as a hydrorhiza. The colony exhibits a distinctive colonial structure, with polyps arising from a branching network of stolons. These colonies typically grow to considerable lengths, with individual polyps reaching up to a few millimeters in size. The polyps display a characteristic bell-shaped structure, equipped with tentacles that aid in capturing prey. The polyps are responsible for feeding, defense, and reproduction.

Habitat and Occurrence

Obelia longissima is primarily found in temperate marine waters, including the North Atlantic and North Pacific Oceans. Its preferred habitat includes rocky shores, tide pools, and kelp forests. This species can tolerate a range of depths, commonly found from the intertidal zone down to depths of several hundred meters. While it prefers a benthic lifestyle, clinging to hard substrates, it may also be found in open water, drifting as a part of plankton.

Taxonomy

Obelia longissima belongs to the Class Hydrozoa, an important class within the phylum Cnidaria. It is further classified within the Order Leptothecata, a group characterized by their polyp morphology and reproductive features. The species falls within the Family Campanulariidae, a family encompassing numerous colonial hydroids known for their bell-shaped polyps.

Feeding

Obelia longissima, like other hydroids, is a carnivorous organism. Its feeding strategy relies on capturing small invertebrates and plankton using its tentacles. Each polyp possesses specialized stinging cells called nematocysts, which are used to paralyze prey. Once captured, the prey is brought to the mouth of the polyp and digested. This feeding strategy allows Obelia longissima to thrive in its diverse marine environments, playing a vital role in the food web.