Holothuroid Species Research Articles

STUDY ON THE HOLOTHUROID FAUNA (ECHINODERMATA: HOLOTHUROIDEA) INHABITING THE SHALLOW WATERS OF THE EGYPTIAN RED SEA

An intensive survey was carried out on the shallow water of the Egyptian coast and Islands of the Red Sea down to 22° N LaL including Gulfs of Aqaba and Suez to study the holothuroid fauna, A total number of 32 holothuroid species was collected belonging to 8 genera; 3 families and 2 orders. A taxonomio key to the species level was constructed to facilitate the identification of the collected species. Among the obtained species, Bohadschia mitsioensis, Bohadschia vitiensis, Holothuria (Fhymiosyeia) conusalba, Labidodemas rugosum, Holothuria (Platyperona) crosnieri, Holothuria (Mertensiotkuria) albofusca and Stichopus horrens were recorded for the first time from the entire Red Sea. Among the 32 species, 5 species (15.6 %) were cosmopolitan, 6 species (18.7 %) were widely distributed, 18 species (56.3 %) were restricted in their distribution to some places in the Indian Ocean and 3 species (9.4 %) were endemic to the Red Sea. Study on micro-habitat distribution showed that species of genera Actinopyga and Bohadschia were surf zo^e species,,, and most species of genus Holothuria were fugitive species, while species of subgenera Cystipus, theelothuria and Metriatyla were mainly fossorial species.

Size and energy content of eggs from echinoderms with pelagic lecithotrophic development

Mean egg energy content (J · egg −1) was significantly and positivelycorrelated with mean egg volume among seven species of holothuroid and asteroid echinoderms with pelagic lecithotrophic (non-feeding) larval development. However, there were not consistent intraspecific relationships between egg size and energy content. Mean egg energy concentration (J · μl −1) was variable but was not significantly correlated with egg volume, in contrast to the negative correlation reported for species with planktotrophic (feeding) larvae. Egg energy concentrations in species with pelagic lecithotrophic larvae are similar to those in species with benthic lecithotrophic development (brooding) and significantly greater than in species with pelagic planktotrophic larvae.

Toxicity of shallow-water Antarctic echinoderms

The toxicity of 23 species of shallow-water antarctic echinoderms from McMurdo Sound was investigated using Gambusia affinis (Vertebrata: Pisces) as a test organism. Ichthyotoxicity assays were conducted on the body wall tissues of thirteen species of asteroids and three species of holothuroids, the tests of three species of echinoids and the arms of three species of ophiuroids and one species of crinoid. Patterns of toxicity were class-specific, with varying degrees of toxicity occurring exclusively among the Asteroidea and Holothuroidea. Seven of the thirteen species of asteroids were mildly to highly toxic (54%), while one of the three holothuroids was mildly and one highly toxic. Toxicity was not related to the level of calcification of the body wall and energy level in asteroids. The only armored asteroid, Notasterias armata, was non-toxic. The occurrence of toxins in the body tissues of antarctic echinoderms is similar in pattern and frequency with that of temperate and tropical species.

The holothuroids, echinoids and asteroids (echinodermata) collected by the Snellius-II expedition

Together the holothuroids, echinoids and asteroids collected by the Snellius-II Expedition represent 144 different species (40 species of holothuroids, 45 species of echinoids and 59 species of asteroids). The collection includes 14 species new to science. Among the remaining 130 species there are five new records for the Austro-Malayan region and 13 new records for the Indonesian seas.

Biochemical composition of antarctic echinoderms

1. 1. The biochemical composition of the body components of 24 species of echinoderms from McMurdo Sound, Antarctica were ascertained. These included 14 species of asteroids, three species of ophiuroids, three species of echinoids, three species of holothuroids, and one species of crinoid. 2. 2. Levels of ash (% dry wt) were high, reflecting large amounts of skeletal material in the asteroid body wall (31.3–80.3%), the ophiuroid disc (48.7–71.7%) and arms (56.8–72.7%), the echinoid test (79.5–80.5%), spines (88.6%) and lantern (79.3%), the holothuroid body wall (31.5–36.2%) and the crinoid cirri (83%), calyx (79%) and arms (63.5%). 3. 3. Levels of insoluble and soluble protein and lipid were high in the nutrient storage organ (pyloric cecum) of the asteroids and the gut of the ophiuroids. 4. 4. Analyses of the biochemical composition of the gonads of 16 echinoderm species reveal high levels of lipid and soluble and insoluble protein. In 88% of the species levels of lipid were higher in ovaries when compared to testes. 5. 5. Levels of carbohydrate were low in all body components. 6. 6. The biochemical composition of antarctic echinoderms is similar to species from other latitudes. High levels of lipid in ovaries of most antarctic echinoderms appear to be related to the preponderance of lecithotrophy at high latitudes.

Papers from the Echinoderm Conference. 3. The reproduction of some echinoderms from Macquarie Island

Three species of starfish, Anasterias directa (Koehler), Anasterias mawsoni (Koehler), and Cycethra macquariensis Koehler, and one species of holothuroid, Pseudopsolus macquariensis (Dendy) were collected over a period of one year from rocky sub-littoral shores at Macquarie Island. Study of preserved collections showed that both Anasterias species and the holothuroid have a brooding mode of reproduction and distinct reproductive cycles. For Cycethra macquariensis no cyclic reproductive pattern was evident. Ovarian condition in Cycethra macquariensis suggested a non-pelagic development; however the mode of this development was not observed. In addition, examination of some specimens of Pseudocnus laevigatus (Verrill), Trachythyone macphersonae Pawson (holothuroids) and Pseudechinus novaezealandiae (Mortensen) (echinoid) showed a brooding habit in Pseudocnus and ovarian conditions that suggested non-pelagic larval development for Trachythyone and pelagic larval development for Pseudechinus.

Organic composition of tropical, polar and temperate-water echinoderms

1. 1. The organic composition (in % dry weight) was estimated for the body wall and pyloric caeca of 9 species of asteroids; the body wall of 17 species of holothuroids; the test, spines and lantern of 13 species of echinoids; and the disc and arms of 11 species of ophiuroids. 2. 2. Protein was the major organic class in the pyloric caeca of asteroids (66–78%); most of this was insoluble protein (42–49%). The pyloric caeca had high levels of lipid (13–19%) and low levels of ash (6.4–11%). 3. 3. Ash was the major constituent of all other body components, being 60–77% of the asteroid body wall; 53–79% of the ophiuroid disc and 74–87% of the arms; 82–93% of the echinoid test, 73–90% of the lantern, and 77–81% of the spines; and 14–81% of the holothuroid body wall. 4. 4. Levels of lipid exceeded levels of carbohydrate in all of these body components. 5. 5. There was no difference in proximate composition with individual body size or with geographical source.