Hydromedusa

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Related to hydromedusae: scyphistoma

Hydromedusa

 

(1) A genus of the Rhynchocephalia family of snake-necked tortoises. It is characterized by a very long neck (which exceeds the length of the dorsal shell) and by the presence of four claws on each of the front legs. The length of the carapace does not exceed 30 cm. There are two species, both freshwater and native to South America. Hy-dromedusa lays its eggs on the shores of inland bodies of water.

(2) Medusoid individuals of certain coelenterates of class Hydrozoa.

References in periodicals archive ?
An explanation for the strong regenerative powers of hydromedusae is their multipotent stem cells, the I-cells, "wandering" between the epidermal and gastrodermal cells.
Coordinated contractions of all four tentacles, with inhibition of swimming, produce a protective response called crumpling (Berger, 1900; Yatsu, 1917), which is similar, at least in function, to the crumple reflex of hydromedusae (Hyman, 1940).
A total of 27 species of jellyfish were identified: 25 hydromedusae and 2 scyphomedusae.
Should network density impact physiological characteristics of the network, such as conduction velocity and facilitation rate, the frenula might play a key role in shaping the velarium for directional fluid ejection and turning, much like exumbrellar radial muscle in the velum of hydromedusae (Gladfelter, 1973; Satterlie et al., 2005).
Key words: Hydromedusae, Blackfordia virginica, morphological variations, Chiapas, Mexico.
Hydromedusae (Cnidaria) of the Chilean Southern channels (from the Corcovado Gulf to the Pulluche-Chacabuco channels).
Hydromedusae exhibit a broad morphological and functional diversity that enables them to occupy a variety of trophic roles (Mills, 1981; Colin and Costello, 2002; Colin et al., 2003, 2006).
Modern trends in the systematics, ecology, and evolution of hydroids and hydromedusae. Claredon, Oxford.
Hydromedusae (Cnidaria, Hydrozoa) can be transported through ballast water, but if the species has a meroplanktonic life cycle, their benthic stage can also be introduced as a part of the ship's fouling fauna (Rees & Gershwin, 2000; Genzano et al., 2006; Miglietta & Lessios, 2009).
Hydromedusae (Cnidaria: Hydrozoa) of Bahia de la Ascension, Caribbean coast of Mexico: a seasonal survey.
Nine macromedusae species were recorded within the captures being the most abundant the hydromedusae Rhacostoma atlanticum (RA) and the joint occurrence of Olindias sambaquiensis (OS) and R.
Electrical activities of a type of electroretinogram recorded from the ocellus of a jellyfish, Polyorchis petzicillatus (Hydromedusae).