A targeted search for echinoderms
in a similar stratigraphic context should yield more well-preserved echinoderms
and new taxa that required rapid burial for preservation.
Studies of larval forms intermediate between feeding and nonfeeding development suggest that the traits characteristic of feeding larvae of echinoderms
can be lost one at a time (Emlet 1986; Olson et al.
Although the astral microtubule signaling hypothesis for furrow specification is well supported by a number of studies using echinoderm
embryos, it has been interpreted as running counter to the large body of evidence in other experimental systems showing that signals derived from the chromosomes and the central spindle are responsible for Rho activation and subsequent cytokinesis (reviewed in Glotzer, 2009; Green et al.
The occurrence of echinoderm
and bryozoan holdfasts indicates that a surface of calcareous sandstone within the Pakri Formation was lithified before encrustation.
represent an important group of invertebrates and a major component of marine communities that may be vulnerable to a variety of environmental pathogens.
Relationships among development, ecology, and morphology in the evolution of Echinoderm
larvae and life cycles.
The 'Saku facies', later formalized as the Saku Member (Roomusoks 1970), was first recognized in the northeastern edge of the outcrop area of the Vasalemma Formation near the Saku settlement and interpreted as a lateral continuation of the echinoderm
grainstone facies (Polma et al.
vitellaria with a bilateral larval skeleton: Evidence for the evolution of ophiurid vitellariae from ophioplutei.
Various types of polyembryony have been described in arthropods, bryozoans, chordates, cnidarians, echinoderms
, and platyhelminthes.
Faunas of the Bromide Formation (Middle Ordovician) of Oklahoma (Sprinkle, J.
The researchers later paired their carbon estimates with population density and mortality data for the different echinoderm
classes worldwide to determine how much calcium carbonate full-sized animals store in their bodies and how quickly that carbon was buried by sediment after the animals die.
(Emlet 1986), four gastropods (Perron 1981; Kempf and Hadfield 1985; Kempf and Todd 1989), a bivalve (Alatalo et al.
In thin sections the AMB 1 facies display a packstone depositional fabric in which the bioclstic components are dominated by the fusulinid forams (24%), brachiopod (14%), bryozoan (10%), bivalve (1%) and echinoderm
For example, crab claws and legs, pieces of echinoderm
test and spines, and pieces of barnacles were often seen in stomach contents.
exigua, may shine light on the evolution of yolk proteins in the echinoderm