et al. 2006). Currently, there are no data about the population densities of D. antillarum in these or other areas of the country.
Other publications about the distribution and density of Venezuelan echinoids
have been mainly related with their association to seagrass, Thalassia testudinum.
Noriega et al. (2002) showed the relation between the density of L. variegatus and
several parameters of the seagrass (percent cover, density and length of the leaves,
density of the roots and total biomass) in Mochima National Park. Total biomass
was the most influential parameter on density (0.6–3.6 ind m
-2 ) and distribution of
the species. At Margarita Island, Gómez (2002, 2003) also found a significant
correlation between the abundance of L. variegatus and the density of T. testudinum,
reporting maximum densities from 38 to 52 ind m
-2 .
The association of ophiuroids to specific habitats like sponges, corals,
octocorals and algae has been described by some authors (Boffi 1972; Hendler and
Miller 1984; Hendler and Littman 1986). Ophiuroids have been reported from the
central-western region of Venezuela to the Orinoco River delta, with 52 identified
species. The Family Amphiuridae is the most diversified one, being found both on
the benthos of shallow and deep water (Borges 2006), while Ophiodermatidae and
Ophiocomidae inhabit primarily shallow water. Villamizar and Laughlin (1991),
studied the animal communities associated to two species of dominant sponges
(Aplysina archeri and A. lacunosa), characterized by different degrees of structural
complexity, in a coral reef of Los Roques Archipelago National Park. Mollusks
had the largest number of species in both sponges (76.51 %); crustaceans had the
largest percent in number of individuals (67.27 %), while fish and ophiuroids had
the largest percent in dry weight (50.45 and 42.68 %, respectively).
In Cubagua Island, Nueva Esparta state, Hernández (2010) reported 24 species
of ophiuroids associated primarily with hard bottom, seagrass, aggregations of the
bivalve Arca zebra and the macroalga Halimeda opuntia. In the Gulf of Cariaco,
revision of the echinoderms resulted in 50 species, 34 genera, 22 families and four
classes: nine species of asteroids, 17 species of ophiuroids, 12 species of echinoids
and 12 species of holothuroids (Amaro 2009).
Studies have been made on the trophic ecology of species of Asteroidea,
Echinoidea and Holothuroidea. Studies on asteroids have focused mainly on the
composition of the diet and trophic interactions. In Golfo Triste, Falcón state,
Bitter (1984) found that Astropecten marginatus is a non-selective consumer,
although it shows a clear preference for mollusks, especially bivalves (33 %) and
gastropods (50 %). Similar results were found by Penchaszadeh (1973) with the
asteroid Astropecten brasiliensis, in which mollusks represented 80 % of the
stomach contents of the studied individuals. In relation to the trophic ecology of
Astropecten brasiliensis riensis and A. articulatus, Bitter and Penchaszadeh (1983)
found the trophic niches of both species overlap, although competition would be
reduced by specialization on the size of the preferred prey. In both species the diet
was mainly mollusks, with gastropods as the most important prey item. The
gastropod Finella dubia accounted for 50 % of the diet of A. brasiliensis riensis
and the gastropod Olivella myrmecoon was 26.5 % of the diet of A. articulatus.
7 Echinoderms from Venezuela
241
Other publications about the distribution and density of Venezuelan echinoids
have been mainly related with their association to seagrass, Thalassia testudinum.
Noriega et al. (2002) showed the relation between the density of L. variegatus and
several parameters of the seagrass (percent cover, density and length of the leaves,
density of the roots and total biomass) in Mochima National Park. Total biomass
was the most influential parameter on density (0.6–3.6 ind m
-2 ) and distribution of
the species. At Margarita Island, Gómez (2002, 2003) also found a significant
correlation between the abundance of L. variegatus and the density of T. testudinum,
reporting maximum densities from 38 to 52 ind m
-2 .
The association of ophiuroids to specific habitats like sponges, corals,
octocorals and algae has been described by some authors (Boffi 1972; Hendler and
Miller 1984; Hendler and Littman 1986). Ophiuroids have been reported from the
central-western region of Venezuela to the Orinoco River delta, with 52 identified
species. The Family Amphiuridae is the most diversified one, being found both on
the benthos of shallow and deep water (Borges 2006), while Ophiodermatidae and
Ophiocomidae inhabit primarily shallow water. Villamizar and Laughlin (1991),
studied the animal communities associated to two species of dominant sponges
(Aplysina archeri and A. lacunosa), characterized by different degrees of structural
complexity, in a coral reef of Los Roques Archipelago National Park. Mollusks
had the largest number of species in both sponges (76.51 %); crustaceans had the
largest percent in number of individuals (67.27 %), while fish and ophiuroids had
the largest percent in dry weight (50.45 and 42.68 %, respectively).
In Cubagua Island, Nueva Esparta state, Hernández (2010) reported 24 species
of ophiuroids associated primarily with hard bottom, seagrass, aggregations of the
bivalve Arca zebra and the macroalga Halimeda opuntia. In the Gulf of Cariaco,
revision of the echinoderms resulted in 50 species, 34 genera, 22 families and four
classes: nine species of asteroids, 17 species of ophiuroids, 12 species of echinoids
and 12 species of holothuroids (Amaro 2009).
Studies have been made on the trophic ecology of species of Asteroidea,
Echinoidea and Holothuroidea. Studies on asteroids have focused mainly on the
composition of the diet and trophic interactions. In Golfo Triste, Falcón state,
Bitter (1984) found that Astropecten marginatus is a non-selective consumer,
although it shows a clear preference for mollusks, especially bivalves (33 %) and
gastropods (50 %). Similar results were found by Penchaszadeh (1973) with the
asteroid Astropecten brasiliensis, in which mollusks represented 80 % of the
stomach contents of the studied individuals. In relation to the trophic ecology of
Astropecten brasiliensis riensis and A. articulatus, Bitter and Penchaszadeh (1983)
found the trophic niches of both species overlap, although competition would be
reduced by specialization on the size of the preferred prey. In both species the diet
was mainly mollusks, with gastropods as the most important prey item. The
gastropod Finella dubia accounted for 50 % of the diet of A. brasiliensis riensis
and the gastropod Olivella myrmecoon was 26.5 % of the diet of A. articulatus.
7 Echinoderms from Venezuela
241