FIGURE 1. Stratigraphic column and map showing the location of the Holothurian Bed locality near Llandrindod, Powys, Wales (inset map shows location within southern UK). Llanfawr Mudstones Lagerstätte refers to Botting et al. (2011), and the Llandegley Rocks Lagerstätte was described by Botting (2005). CMF: Camnant Mudstones Formation. The boundary between the Didymograptus murchisonii and Hustedograptus? teretiusculus biozones is not well constrained, except in the stream itself, where it is somewhat faulted (Sheldon 1987b).

FIGURE 2. Outcrop of the Holothurian Bed, in the upper part of the section; the interval described here overlies a thick tuff bed visible in the upper half of the view. Beds underlying the tuff are blue-grey mudstones with similar fauna to the non-exceptional components found above it. The tuff bed is 27 cm thick.

FIGURE 3. Trilobites from the Holothurian Bed, Bach-y-Graig. 1, Ogygiocarella? sp., recently moulted, wrinkled specimen NMW2011.2G.7, scale bar equals 5 mm. 2,Ogyginus corndensis, articulated moult NMW2011.2G.6, scale bar equals 1 mm. 3, Ogyginus corndensis meraspis, NMW2011.2G.31, scale bar equals 1 mm; 4, Cnemidopyge parva NMW2011.2G.28, scale bar equals 5 mm; 5, Protolloydolithus reticulatus NMW2011.2G.4, scale bar 5mm; 6, Microparia sp. NMW2011.2G.20, scale bar equals 1 mm; 7, Protolloydolithus reticulatus showing replacement of skeleton by pyrite NMW2011.2G.30, scale bar 1 mm; 8, Ogyginus corndensis NMW2011.2G.15, scale bar equals 1 mm; 9, Cluster of trilobite fragments NMW2011.2G.27, scale bar equals 1 mm.

FIGURE 4. Representative fossils from the Holothurian Bed, Bach-y-Graig. 1, undescribed bivalve NMW2011.2G.11, scale bar equals 1 mm; 2, fragment of undescribed hexactinellid sponge, showing typical preservation due to weathered pyrite, NMW2011.2G.14, scale bar equals 1 mm; 3, undescribed palaeoscolecidan worm with dark carbonaceous and/or phosphatic preservation of plates NMW2011.2G.26, scale bar equals 1 mm.

FIGURE 5. Echinoderms from the Holothurian Bed, Bach-y-Graig. 1, articulated mitrate (Anatifopsis?) NMW2011.2G.12, scale bar equals 1 mm; 2, undetermined carpoid(?) echinoderm NMW2011.2G.25, scale bar equals 1 mm; 3, undetermined "cystoid" with arachnoid plates, NMW2011.2G.34, scale bar equals 1 mm. See also Figure 9 for holothurian specimens.

FIGURE 6. Graptolites and brachiopods from the Holothurian Bed, Bach-y-Graig. 1, Cryptograptus tricornis showing typical preservation for graptolites NMW2011.2G.2, scale bar 2 mm; 2, Hustedograptus? teretiusculus with combination of carbonaceous and probably aluminosilicate preservation NMW2011.2G.3, scale bar equals 2 mm; 3, Dendrograptus sp. NMW2011.2G.1, scale bar equals 5 mm; 4, Palaeoglossa attenuata NMW2011.2G.19, scale bar equals 2 mm; 5, Schizotreta sp. encrusting a weakly preserved substrate, NMW2011.2G.9, scale bar equals 5 mm; 6, Small cluster of Apatobolus? micula (see also Figure 8.5) NMW2011.2G.37, scale bar equals 2 mm.

FIGURE 7. Species-abundance curve obtained from in situ sampling exercise over two days, excluding Apatobolus? micula. Note that the curve appears to level out at approximately 48 specimens, but we are aware of a minimum diversity of 52 species at the site, and the true diversity will be substantially higher.

FIGURE 8. Specimens from the Holothurian Bed, Bach-y-Graig showing ecological relationships. 1, organic matter with feeding ostracodes (three examples arrowed) NMW2011.2G.8, scale bar equals 1 mm; 2, Cluster of dissociated Anatifopsis? plates and trilobite sclerites interpreted as possible cephalopod midden, NMW2011.2G.16, scale bar equals 5 mm; 3, pellet composed of fibrous carbonaceous material NMW2011.2G.23, scale bar equals 1 mm; 4, pellet composed of crushed valves of Apatobolus? micula, NMW2011.2G.24, scale bar equals 1 mm; 5, Apatobolus? micula showing repair from probable attempted predation damage, NMW2011.2G.37, scale bar equals 1 mm.

FIGURE 9. Holothurian Oesolcucumaria eostre gen. et sp. nov. 1-3, holotype NHM EE8734; 1, overall view; 2, detail of part of calcareous ring and short ambulacrum; 3; camera lucida drawing of area illustrated in 3; 4, paratype NHM EE8736, large weathered specimen, near-complete; 5, paratype NHM EE8737, anterior part of holothurian showing weakly pyritised oral ring and possibly also ambulacral structures; 6, paratype NMW2011.2G.21, complete weathered specimen with poorly preserved fine detail; 7, paratype NHM EE8739, isolated calcareous ring. Scale bar equals 1 mm.