OSSICLES

by

Claude MASSIN

PEET Workshop

Brussels 04-08 December 2006

OSSICLES

• First drawing: Strussenfelt, 1765• Identified as such Lesson, 1830 (anchor)• used for taxonomy since 1860 • Change with growth: increase in size,

diminish in size, disappear, become more spiny, change of shape

• Neopentadactyla mixta: tables with 2 pillars tables with 4 pillars

OSSICLES

• Change with growth: increase in size, diminish in size, disappear, become more spiny, change of shape

• Neopentadactyla mixta: tables with 2 pillars tables with 4 pillars

• Pearsonthuria graeffei

OSSICLES

• Change with growth: increase in size, diminish in size, disappear, become more spiny, change of shape

• Neopentadactyla mixta: tables with 2 pillars tables with 4 pillars

• Pearsonthuria graeffei

• Heterocucumis steineni

OSSICLES

• Change with growth: increase in size, diminish in size, disappear, become more spiny, change of shape

• Neopentadactyla mixta: tables with 2 pillars tables with 4 pillars

• Pearsonthuria graeffei• Heterocucumis steineni • Change between juveniles and sub-adults 1mm to 20-

30mm• Afrocucumis straki

Tables:1 pillar ending in one or several points; disc with many peripheralholes (Synallactid like)

or 1 pillar ending in several hooks, disk without peripheral holes(Molpadid like)

2 pillars ending each in one or several points or fused in a singlepoint, or forming a small crown of spines, disc circular orelongated and arched (Dendrochirotid like)

3 pillars ending in a crown of spine or not (synallactids,aspidochirotids, dendrochirotids)

Tables4 pillars ending in a crownof spines or not (dendrochirotids, aspidochirotids) with thefollowing subcategories:

- Disc rounded or cruciform (Synallactid like)- (H. kurti: 25-35 mm; H. altimensis: 7-9 mm)

- Edge of the disc smooth, knobbed or spiny- Disc without peripheral holes, with few

peripheral holes or with numerous peripheral holes- H/W of the table>>1; = 1; <1

- Pillars ending in a crown of spines narrower,equal or larger than the disc

Tables- Crown of spines with a large central opening, a small

central opening or several central openings- Crown of spines forming a circle or forming a Maltese

cross- Pillars fused, smooth and endingin a single point or spiny and endingin several points (Stichopus, Holothuria)

- Disc of the table reduced or absent(Halodeima) disc of the table welldeveloped

- 5 pillars or more (Holothuria (Metriatyla); Eostichopus)

- Table transformed in fenestrated sphere

Pseudo tables

Rocket like table ofPearsonothuria graeffei

Pseudo-tables ofThelenota spp

Pseudo-tables of Cladolabes

New names are to be found for these ossicles

Buttons2 -10 pairs of holes with samediameter on two rows; no single hole at the extremities (angleof growth 90°), with or without a median longitudinal ridge

Smooth, knobbed or transformed in ellipsoids

PseudobuttonsAs a button but with a single row of holes, a second row with 1-2 holes can bepresent; often irregular and twisted

Perforated plates

Rounded- Tube feet end plate madeof one piece or several pieces

- Table reduced to the disc- - Lenticular perforated plate with or without eccentric spire

Baskets: small (4 holes), more or less arched perforated plate with or without a cross beam, smooth or knobbed (dendrochirotids )

Perforated platesElongated- Derived from buttons(all the holes with same diameter)

or derived from perforated rods (central holes larger than peripheral holes), with or without a median longitudinal ridge

- Racket shape with handlesmooth (molpadids)

or spiny (dendrochirotids)

Derived from 2 dimensionalbranched rods (Stichopus, Thelenota)

Rods

- Simple, rarely bifurcated, spiny or smooth,straight or curved, without holes (cf tentaclerods of many aspidochirotids)

- - Two dimensional large branchedrods, spiny (Stichopus, Thelenota)- or three dimensional branched rods,smooth or spiny (most of the elasipodids)

- Perforated rods (at the extremities and or alongthe axes) (Holothuria) with or without amedian longitudinal ridge

Rods- Rods non perforated atthe extremities but withspiny lateral processesand/or a central perforatedprocess (Stichopus)

- Massive perforated rods(at the extremities and/oralong the edges) smooth or spiny(Selenkothuria)

- Small rods fromActinopyga sppand Bohaschia spp

RodsC-shape rods regular or irregular (irregular looklike rosettes)- from Stichopus

- from ApodidsChiridota(slender or thick)

- from Holothuria longitudinal muscle

- from Stichothuria

S-shape ossicles from Stichopus

GranulesSpherical or contorted, non perforatedmaximum 10 µm long (Thelenota)

Miliary granules- Spherical, ovoid or elongated ossicles made of tri-dimensional branched rodscovered by numerous granules(Dendrochirotids; apodids?)- U-shape ossicles with onerow of external granules (apodids)

GrainsSpherical or elongated ,non perforated ossicles minimum 15 µm across (Bohadschia)

Elongated or irregular with 1-3 holes

(Bohadschia)

RosettesSmall branched rods (angle of growth 120°) with rounded extremities more or less plump (Actinopya,Bohadschia,Stichopus, dendrochirotids)

Branches of the rods may fuse giving rise to smallperforated plate (4 holes: 2 large and 2 small atthe extremities)(Halodeima)

Pearsonothuria graeffei

Between grains, rosettes and rods all intermediary stages

Anchors, anchors plates, wheels , hooks or sigmoid rods

QUESTIONS

• What is a pseudo table?

• What is a rosette?

• What is a grain, granule, miliary granule?

• What is a C-shape rod?