no recruitment during this period. The high density (35 ind m
-2 ) and the trophic
range suggest a potential role in the hard bottom community (Meretta et al.
2009b).
Stomach contents of Astropecten brasiliensis and Luidia ludwigi scotti have
been analyzed by Brogger and Penchaszadeh (2008) at Puerto Quequén coast
(38°37
0 S, 58°50
0 W) between 40 and 60 m depth. Astropecten brasiliensis was the
most abundant sea star sampled and showed the most diversified diet, with a total
of *28 different items. Bivalves and gastropods were dominant. In contrast,
L. ludwigi scotti was found in lower numbers and preyed upon eight species.
Bivalves, foraminiferans and ophiuroids were the most common prey. There were
differences not only in items eaten by the two species, but also in the size of the
common prey. This suggests that differences in diet may allow the coexistence of
the two predators. Penchaszadeh (1973) also observed mollusks as main prey items
for A. brasiliensis off Mar del Plata.
The sea star Cosmasterias lurida (Fig. 11.3a) shows a continuous distribution
from the Argentine shelf (38°S, 57°W) to the Chilean coastline (29°S, 78°W)
(Bremec et al. 2000). It is usually found on subtidal coarse bottoms from 0 to
650 m depth (Clark and Downey 1992) in very low densities (Bremec et al. 2000).
Reproduction has been studied on pier piles of Almirante Storni in NG (Pastor de
Ward et al. 2006). This highly modified habitat had an unusually supply of mussels
and large aggregations of sea stars. Gametogenesis takes place from June to
January, sexual maturity occurs during the summer, and spawning in April. The
gonadal index and pyloric caecum index tended to have an inverse relationship,
but this was statistically significant only in males. However, biochemical analyses
indicated no transfer of nutrients between pyloric caeca and gonads in either sex.
Pastor de Ward et al. (2006) suggested that the high availability of trophic
resources in the study area could be the clue to the high allocation of nutrients, the
absence of nutrient transfer from the pyloric caeca to the gonads during proliferation and the continuous proliferation of oocytes in C. lurida at the Almirante
Storni pier.
The brooding sea star Ctenodiscus australis is distributed along the east coast of
South America, from southern Brazil (23°00
0 S, 41°40
0 W) to TF and the Malvinas
Islands, between 70 and 700 m depth. It is usually found on sand bottoms,
occasionally on coarse sand or sand with stones (Clark and Downey 1992). This is
a conspicuous species in the community associated with the shelf-break front
(Bremec and Lasta 2002). While brooding, the young (at different stages of
development) are hidden under the paxillae, mainly at the base of the arms near the
interradius. The youngest stages were entirely hidden by the paxillae. In advanced
stages, parts of their bodies protruded between the spines and are easily seen. The
youngest stages show a larva typical of an abbreviated development (e.g. a yolky,
nonfeeding larva) (Lieberkind 1926). The larvae lack arms and ciliated bands.
Nothing is known about internal morphology of the larvae, but they are probably
yolky, or has a direct-development mesogen (McEdward and Miner 2001).
The pterasterid Diplopteraster clarki has a continuous distribution along the
coast of Argentina, from RP to waters off SJOG, between 82 and 600 m depth
11 Echinoderms from Argentina
373
-2 ) and the trophic
range suggest a potential role in the hard bottom community (Meretta et al.
2009b).
Stomach contents of Astropecten brasiliensis and Luidia ludwigi scotti have
been analyzed by Brogger and Penchaszadeh (2008) at Puerto Quequén coast
(38°37
0 S, 58°50
0 W) between 40 and 60 m depth. Astropecten brasiliensis was the
most abundant sea star sampled and showed the most diversified diet, with a total
of *28 different items. Bivalves and gastropods were dominant. In contrast,
L. ludwigi scotti was found in lower numbers and preyed upon eight species.
Bivalves, foraminiferans and ophiuroids were the most common prey. There were
differences not only in items eaten by the two species, but also in the size of the
common prey. This suggests that differences in diet may allow the coexistence of
the two predators. Penchaszadeh (1973) also observed mollusks as main prey items
for A. brasiliensis off Mar del Plata.
The sea star Cosmasterias lurida (Fig. 11.3a) shows a continuous distribution
from the Argentine shelf (38°S, 57°W) to the Chilean coastline (29°S, 78°W)
(Bremec et al. 2000). It is usually found on subtidal coarse bottoms from 0 to
650 m depth (Clark and Downey 1992) in very low densities (Bremec et al. 2000).
Reproduction has been studied on pier piles of Almirante Storni in NG (Pastor de
Ward et al. 2006). This highly modified habitat had an unusually supply of mussels
and large aggregations of sea stars. Gametogenesis takes place from June to
January, sexual maturity occurs during the summer, and spawning in April. The
gonadal index and pyloric caecum index tended to have an inverse relationship,
but this was statistically significant only in males. However, biochemical analyses
indicated no transfer of nutrients between pyloric caeca and gonads in either sex.
Pastor de Ward et al. (2006) suggested that the high availability of trophic
resources in the study area could be the clue to the high allocation of nutrients, the
absence of nutrient transfer from the pyloric caeca to the gonads during proliferation and the continuous proliferation of oocytes in C. lurida at the Almirante
Storni pier.
The brooding sea star Ctenodiscus australis is distributed along the east coast of
South America, from southern Brazil (23°00
0 S, 41°40
0 W) to TF and the Malvinas
Islands, between 70 and 700 m depth. It is usually found on sand bottoms,
occasionally on coarse sand or sand with stones (Clark and Downey 1992). This is
a conspicuous species in the community associated with the shelf-break front
(Bremec and Lasta 2002). While brooding, the young (at different stages of
development) are hidden under the paxillae, mainly at the base of the arms near the
interradius. The youngest stages were entirely hidden by the paxillae. In advanced
stages, parts of their bodies protruded between the spines and are easily seen. The
youngest stages show a larva typical of an abbreviated development (e.g. a yolky,
nonfeeding larva) (Lieberkind 1926). The larvae lack arms and ciliated bands.
Nothing is known about internal morphology of the larvae, but they are probably
yolky, or has a direct-development mesogen (McEdward and Miner 2001).
The pterasterid Diplopteraster clarki has a continuous distribution along the
coast of Argentina, from RP to waters off SJOG, between 82 and 600 m depth
11 Echinoderms from Argentina
373