Sea cucumbers symmetry (Echinodermata: Holothuroidea)

  title={Sea cucumbers symmetry (Echinodermata: Holothuroidea)},
  author={Alexey V Smirnov},
  journal={Paleontological Journal},
  • A. Smirnov
  • Published 4 December 2014
  • Biology
  • Paleontological Journal
The types of symmetry that are characteristic for the class Holothuroidea and reflect different stages in the evolution of this group of echinoderms and the role of paedomorphosis in its origin are analyzed. A hypothesis is proposed to explain the distinctive structure of the water vessel (ambulacral) system of sea cucumbers and the origin of the class Holothuroidea. The development of holothurians was interrupted at the stage of five primary tentacles. It resulted in changing of the mode of… 
Parallelisms in the evolution of sea cucumbers (Echinodermata: Holothuroidea)
It is hypothesized that the concave cup-shaped sclerites with three to five rays occurring in the family Laetmogonidae (order Elasipodida) are of paedomorphic origin and correspond to the early growth stages of the laetmogsonid wheels.
Paedomorphosis and heterochrony in the origin and evolution of the class holothuroidea
The processes of paedomorphosis and heterochrony played an important role not only in the origin and formation of the class Holothuroidea, but also during its evolution of the order Synaptida.
Origin of the Class Holothuroidea
Among the specific characters of holothurians, the main ones are: the structure of the ambulacral (water vascular) system, the presence of oral (buccal) tentacles, the calcareous ring, and bilateral
Origin and significance of Lovén's Law in echinoderms
Abstract. Lovén's Law described the position of larger basicoronal ambulacral plates in echinoids. The smaller basicoronal plates form first in ontogeny. We restate Lovén's Law to describe the
Systematic Studies on Sea Cucumbers of the Family Stichopodidae (Echinodermata:Holothuroidea)
This dissertation presents a collection of some studies done on the systematics of the family Stichopodidae and proposes one new genus, one new species, two new species combinations, and one resurrected species name that are proposed in this dissertation.
Early Jurassic “worm holothurians” (Echinodermata) as faecal traces of a worm-like holothurian-eater reflecting the consumed species
Abstract“Worm holothurians” from a sequence of Early Liassic (Hettangian) shales at Göttingen (Germany) are string- and strip-shaped relics of faeces of a worm-like holothurian-eater. They consist of
Retinoic Acid Signaling Regulates the Metamorphosis of Feather Stars (Crinoidea, Echinodermata): Insight into the Evolution of the Animal Life Cycle
This work investigated the role of RA signaling during the metamorphosis of the feather star, Antedon serrata, and found that exogenous RA treatment on doliolaria larvae induced meetamorphosis, like in starfish.
Histologic Examination of a Sea Pig (Scotoplanes sp.) Using Bright Field Light Microscopy
Control histology for future investigations of sea pigs and related animals using bright field microscopy is provided, and a presumed protozoal cyst was identified in the aboral intestinal mucosa, and was histologically similar to previous reports of coccidians.
• Mike Reich — On the relationships of early holothurians and ophiocistioids: A question of wheels?
Meetings 2014 and communications on sea cucumbers 1) 47th North American Echinoderm Conference, University of West Florida, Pensacola, Florida, 1–6 June 2014 • Paulay Gustav, Scott Smiley, David L.
A Review on Knowledge and Research of Interstitial Sea Cucumber
Abstract The interstitial environment of sandy bottoms is an enigmatic habitat that forms unique ecosystems containing significant numbers of biodiversity. One of the lesser known marine invertebrate


Paedomorphosis and heterochrony in the origin and evolution of the class holothuroidea
The processes of paedomorphosis and heterochrony played an important role not only in the origin and formation of the class Holothuroidea, but also during its evolution of the order Synaptida.
  • S. Smiley
  • Biology, Medicine
    The Biological bulletin
  • 1986
Holothurian metamorphosis for a relatively unspecialized aspidochirote, Stichopus californicus, is described here and assignment of holothurians with echinoids to the subphylum Echinozoa is discussed.
From Vendian to Cambrian: the beginning of morphological disparity of modern metazoan phyla
  • S. Rozhnov
  • Biology, Medicine
    Russian Journal of Developmental Biology
  • 2010
It is shown that major features of a morphogenetic archetype could be retained from the time the taxon was formed, and probably, an expanded placozoan level of organization can be assumed for most Vendian animals.
Although invertebrate deuterostomes are believed to lack discrete excretory organs, an analysis of the metamorphosis of the larval nephridia suggests that adult echi...
Bi-penta-bi-decaradial symmetry: A review of evolutionary and developmental trends in holothuroidea (echinodermata)
  • Kerr, Kim
  • Biology, Medicine
    The Journal of experimental zoology
  • 1999
Holothuroidea, comprising the sea cucumbers, is the least studied class of extant echinoderms, yet this group possesses a wealth of features of potential interest to developmental and evolutionary biologists, and the morphological and molecular evidence suggests almost an inversion of the prevailing higher level classification.
Origin of the holothurians (Echinodermata) derived by constructional morphology
The present approach, which follows the principles of constructional morphology, supports former views that the holothurian predecessor must have been echinoid-like, and confirms the existence of respiratory trees by no later than the Middle Devonian.
A rays-as-appendages model for the origin of pentamerism in echinoderms
It is proposed that a duplication of the uniray occurred and resulted in the addition of a pair of rays that followed Bateson's rules of symmetry to form a three-rayed 0-1-2, -A-BA, construction.
System of the class Holothuroidea
Various interpretations of the holothurian system and phylogeny are critically reviewed and the main characters that form the basis of the existing systematics of this group are analyzed. A system of
The anteroposterior axis in echinoderms and displacement of the mouth in their phylogeny and ontogeny
Dislocation of Hox-genes in sea urchins is explained by the necessity to preserve the spatial and temporal colinearity in the course of the convergence of the starting and final stages of the mouth displacement process, similar to the elevation process in crinoids.
Deuterostomes in a twist: the origins of a radical new body plan
  • A. Smith
  • Biology, Medicine
    Evolution & development
  • 2008
Comparing echinoderm ontogeny and genetic developmental signalling patterns with those of their sister group, the hemichordates, suggests that an evolutionary switch from posterior facultative to anterior obligate larval attachment proved the critical trigger for this transformation.