Monobrachium parasitum Mereschkowsky 1877
- Dataset
- First record of Monobrachium parasitum Mereschkowsky, 1877 (Cnidaria: Hydrozoa) from Brazil, in the tropical southwestern Atlantic, and its implication for bipolarity concepts
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Cnidaria
- class
- Hydrozoa
- order
- Limnomedusae
- family
- Monobrachiidae
- genus
- Monobrachium
- species
- Monobrachium parasitum
description
Description Colonies reptant, consisting of many zooids arising from a network of stolons adhering to valves of host bivalve shell (Figures 2 A, 3 A) and extending from surface to margin, with a number of free ends projecting beyond it by means of typical dactylozooids (see Figures 2 A, 3 A); polyps cylindrical, rising directly from stolons, terminating in a large mouth, bearing nematocysts over entire length (Figure 2 C), each polyp provided with a long and vigorous tentacle having large nematocysts (microbasic euryteles) scattered over its full length (Figure 2 D). One colony fertile, with a single globular gonophore rising from the stolon by means of a small peduncle, resembling a reduced medusoid, gonophore with a thick periderm capsule filled with masses of (probable) female generative cells placed along the radial canals (Figure 2 A).
distribution
Distribution Most previous records of M. parasitum are from the northern hemisphere. Its original description is from the White Sea by Mereschkowsky (1877). Other records include those of Stafford (1912 apud Fraser 1944), in the Gaspé region (Atlantic coast of Canada); Fraser (1918), from Vancouver Island, British Columbia (Pacific coast of Canada); Hand (1957), in shallow waters of California and Baja California; Naumov (1969), in the southernmost part of the Sea of Okhotsk, Russia; Ramil (1988), Besteiro et al. (1990), and Altuna (2007), in Galicia, Iberian Peninsula; Medel and Lòpez-González (1996), in the Mediterranean; and a doubtful record from the Sea of Yûbetsu, Hokkaido, Japan, by Kubota (1991). Its distribution, as given by Naumov (1969), extends from the “ White, Barents, Kara, and Chukchi seas, seas of Okhotsk and Japan; coasts of Spitsbergen and western Greenland; Atlantic and Pacific coasts of Canada; coast of California. ” In the southern hemisphere, records of M. parasitum are from the South Orkney Islands, Elephant Island, and the region on the west side of the Antarctic Peninsula (Stepanjants et al. 1997; Jarms and Mühlenhardt-Siegel 1998).
materials_examined
Type locality Bay of Onega, White Sea, 9 m depth, on the pelecypod Macoma calcarea (= Tellina calcarea).