Apsolidium falconerae, O’Loughlin, 2007

O’Loughlin, P. Mark, 2007, New cucumariid species from southern Australia (Echinodermata: Holothuroidea: Dendrochirotida: Cucumariidae), Memoirs of Museum Victoria 64, pp. 23-34 : 24

Apsolidium falconerae sp. nov.

Figures 1a , 2a , 3a–d , 4a

Material examined. Holotype: Australia, Victoria, Western Port, Phillip I., Cat Bay , shallow sublittoral, covered with detrital material (held by tube feet), attached to undersurface of rock, C. Handreck, 7 Mar 1995, NMV F109375 .

Description. Body length 34 mm, maximum width 15 mm (preserved; tentacles excluded, partly withdrawn); body rounded dorsally, flat ventral sole, tapering from wide high oral end to lower narrow anal end; wide dorso-anterior oral end; short dorso-posterior rounded blunt anal cone; dorsal and lateral body wall thin, densely calcareous, rough, small irregularly distributed scales evident, not overlapping; ventral body wall distinctly thin semi-trunslucent sole with ossicles evident, irregularly oval, tapering posteriorly, rounded not acute junction with ventro-lateral body wall, peripheral series of tube feet; 9 dendritic tentacles, 8 large, 1 small ventral; radial and interradial calcareous ring plates wide posteriorly with central deep notch, radially tapering anteriorly to blunt columnar projection, interadially to thick point, heights of plates subequal; small tube feet scattered closely over dorsal and lateral surfaces; large tube feet ventrally, continuous peripheral irregular series 5-wide, mid-ventral radial series 2–4 wide; single dorsal madreporite near vascular ring, irregular short-branched form, less than 1 mm long; single ventral polian vesicle; gonad tubules unbranched; longer respiratory tree branch extends half coelom length; longitudinal muscles thin, flat, retractor muscles branch off in mid-body.

Ossicles. Dorsal and lateral body wall and tube feet with multilayered ossicles (small scales), buttons, cups, tube foot endplates, tube foot perforated support plates: multilayered ossicles up to 896 μ m long; buttons irregular, thick, knobbed, perforated, 104–192 μ m long, most small, some with secondary layer developments, some intergrading with multilayered ossicles; complex bluntly spinous cups, basal cross, branching from rim to close over cup to varying extents, 112–144 μ m long; small endplates, up to 184 μ m diameter, smallest perforations centrally; tube foot support plates irregularly oval, perforated, denticulate on 1 margin, sometimes curved, typically 160 μ m long. Ventral tube feet with endplates, support plates, narrow plates: endplates up to 280 μ m diameter, small perforations centrally, large peripherally; support plates elongate, bent or curved, perforated, denticulate on 1 margin, typically 256 μ m long. Sole with plates and cups: plates perforated, thick, knobbed, single-layered, variably oval to narrowly elongate, up to 400 μ m long; cups rare, 80 μ m long, thin-walled, shallow, denticulate margin, denticulations slightly globose. Tentacles with rods, narrow plates, small plates, lacking rosettes: rods thick, straight or curved, large lateral perforations, small terminal perforations, up to 296 μ m long (intergrade with narrow plates); narrow plates bent or curved, thick, few central and distal perforations, margin thickly denticulate, up to 200 μ m long; small plates tentacle dendritic branch endplates, thin-walled, perforated, irregularly oval, cupped or curved, marginally finely denticulate, typically 56 μ m long.

Colour. Live: body white dorsally and ventrally; tentacle dendritic branches yellow (pers. comm. Clarrie Handreck). Preserved: body and tentacle dendritic branches white; tentacle trunks and oral disc with dark brown flecking.

Distribution. Victoria, Western Port, Phillip I., Cat Bay; 0– 1 m.

Etymology. Named for Audrey Falconer (Marine Research Group of Victoria), in appreciation of her dedication to marine invertebrate studies on the coast of Victoria, and especially for her contribution to photography in this work.

Remarks. The genus Apsolidium O’Loughlin and O’Hara, 1992 was described for 3 southern Australian species: A. alvei , A. densum , A. handrecki . Apsolidium falconerae sp. nov. shares the distinctive diagnostic characters of the genus. The body form and cup ossicle form distinguish A. falconerae from the other 3 species. None of the other 3 species has a body form that tapers distinctly from anterior to posterior, or has dorsal and lateral body wall cups with an extensively developed rim that creates variably closed cups. A. falconerae also lacks the tentacle rosette ossicles of each of the other 3 species. It is assumed here that the single small ventral tentacle of A. falconerae is exceptional and would normally be a pair.

Figures

Figure 1. a, Apsolidium falconerae sp. nov., holotype, from Phillip I., NMV F109375, preserved, 34 mm long, lateral view showing thick calcareous dorsal and lateral body, thin-walled sole, mid-ventral radial tube feet; insert with radial (left) and interradial (right) plates of calcareous ring. b, Neoamphicyclus mutans (Joshua, 1914), live colour, collected by Mark O’Loughlin from Flinders ocean platforms on 13 February 2007, 60 mm long, lateral view, NMV F123862. c, Neoamphicyclus altoffi sp. nov., holotype, from Fremantle, WAM Z279-92, preserved, 33 mm long, dorso-lateral view; insert with radial (left) and interradial (right) plates of calcareous ring. d, Neoamphicyclus altoffi sp. nov., tentacles showing white calcareous band of ossicles at base, NMV F132704. e, Neoamphicyclus materiae sp. nov., holotype, from Flinders, NMV F132722, preserved, 35 mm long, ventral view; insert with radial (left) and interradial (right) plates of calcareous ring. f, Neocucumella turnerae sp. nov., holotype, from Derwent estuary, TM H3295, preserved, 46 mm long; insert with radial (left) and interradial (right) plates of calcareous ring.

Figure 2. Body wall mounts. a, Apsolidium falconerae sp. nov., holotype, NMV F109375, knobbed plates in ventral body wall. b, Neocucumella turnerae sp. nov., paratype, TM H3296, endplate in ventral body wall; absence of other ossicles. c, Neoamphicyclus altoffi sp. nov., holotype, WAM Z279-92, table discs in body wall; insert with lateral view of table showing spire, NMV F132704. d, Neoamphicyclus mutans (Joshua, 1914), NMV F109315, table discs in body wall; insert showing table spire. e, Neoamphicyclus materiae sp. nov., paratype NMV F76360, table discs in body wall; inserts with lateral view of tables showing spires, paratype, NMV F76364. f, Neoamphicyclus lividus Hickman, 1962, table discs in body wall, NMV F58698.

Figure 3. Apsolidium falconerae sp. nov., ossicles, holotype, NMV F109375. a, scale (multilayered ossicle) from dorsal body wall. b, dorsal body wall; knobbed button and cup (top right); 4 perforated tube foot support plates. c, partially “closed” cups from dorsal body wall; 2 views of cross at base of cups (left); view of partially closed top of cup (upper right); lateral view of cup (lower right). d, ventral body wall (sole); elongate knobbed plate (upper); 4 tube foot support plates (lower).

Figure 4. Tentacle ossicles. a, Apsolidium falconerae sp. nov., holotype, NMV F109375, perforated plates and rods. b, Neoamphicyclus altoffi sp. nov., rosettes from lower tentacle (base), NMV F132704. c, Neoamphicyclus altoffi sp. nov., rods from upper tentacle, NMV F132704. d, Neoamphicyclus materiae sp. nov., paratype, NMV F76364, rods. e, Neoamphicyclus mutans (Joshua,1914), NMV F109315, rosettes from upper tentacle. f, Neocucumella turnerae sp. nov., paratype, TM H3296; rosettes from disc and oral papillae (left); rods from tentacles (right).