Phyllophorella thyonoides (H. L. Clark, 1938 )

O’Loughlin, P. Mark, Barmos, Shari & VandenSpiegel, Didier, 2012, The phyllophorid sea cucumbers of southern Australia (Echinodermata: Holothuroidea: Dendrochirotida: Phyllophoridae), Memoirs of Museum Victoria 69, pp. 269-308 : 280-285

Phyllophorella thyonoides (H. L. Clark, 1938)

Figures 9 , 10 , 13f

Phyllophorus thyonoides H. L. Clark, 1938: 492–494 , fig. 48.—H. L. Clark, 1946: 409.

Phyllophorus ventripes Joshua and Creed, 1915: 19 , pl. 2 fig. 1, pl. 3 fig. 5. (part).

Lipotrapeza ventripes .—H. L. Clark, 1938: 495–496.—H. L. Clark, 1946: 412.— Heding and Panning, 1954: 175, fig. 83 (from Joshua and Creed 1915).— Smith, 1970: 94.— Rowe, 1982: 464.— Rowe and Gates, 1995: 311. (part).

Phyrella thyonoides .— Heding and Panning, 1954: 183–184, fig. 88 (from H. L. Clark 1938).— Rowe and Gates, 1995: 313–314.

Material examined. Phyllophorus ventripes Joshua and Creed, 1915 . Paratype. South Australia, J. C. Verco, SAM K1375 (1; earliest label “type material”; recent label “type”; judged here to be a paratype; determined as Phyrella thyonoides by F. W. E. Rowe 1977; confirmed here).

Other material. South Australia, J. C. Verco, SAM K2597 (1; determined as Phyllophorus (Phyllophorella) thyonoides by F. W. E. Rowe 1977; confirmed here).

Western Australia, Garden I., Careening Bay , intertidal sand flats, 26 Nov 1961, WAM Z31837 (1) ; sand flats, 20 Dec 1969, WAM Z31962 (1) ; Cockburn Sound, Woodman’s Point, seagrass bank, 1 Dec 1957, WAM Z31834 (2) ; 1 m, 18 Mar 1972, WAM Z31975 (1) ; 100 km S of Geraldton, Cliff Head , seagrass rhizomes, 2 m, 2 Sep 1985, WAM Z21214 (2) ; 3 Jun 1986, AM J21716 (4).

Diagnosis. Up to 60 mm long, up to 25 mm diameter (preserved, tentacles withdrawn), curved cylindrical body tapered to rounded upturned ends orally and anally, variably with ventral belly, thick firm body wall; external anal scales not detected; 20 tentacles, 15 variably large outer, 5 inner small; complete spaced cover of large and small tube feet, larger and more numerous ventrally, disc ends up to 0.7 mm diameter, smaller dorsally, orally, anally, radial to scattered tube feet cross introvert, spaced paired posterior radial series; calcareous ring with 10 posterior composite tapering projections arising from radial plates only (smaller specimens) or jointly from both radial and inter-radial plates (larger specimens), ring not tubular, posterior ends free tapering tails generally sub-equal with anterior plates and projections, spaces between posterior prolongations extending anteriorly to similar extents radially and inter-radially, form of plates and composite components variable; short stone canal, multi-lobed madreporite close to vascular ring; 1–3 polian vesicles; gonad tubules arise in series along gonoduct on each side of dorsal mesentery, tubules not branched.

Mid-body wall with scattered tables, discs regular to irregular in form, some with appearance of being incomplete, rounded quadrangular to oval, commonly 96 µ m long, frequently up to 112 µ m long, rarely up to 144 µ m long, margin lobed, lobes smooth or denticulate, commonly central and about 8 outer perforations, sometimes many perforations anally, spires frequently with 4 pillars up to 48 µ m high, rarely 3, 5, 6 pillars; tube foot ossicles endplates and endplate support ossicles only; endplates with denticulate margin, irregular perforations similar size, diameters up to 600 µ m; endplate support ossicles up to 184 µ m long, dumbbell-shaped rods with rounded ends with large and small perforations and denticulate margin, and narrow multi-perforate plates with denticulate margin; tentacles with rods and rosettes, larger rods dumbbell-shaped, widened and perforate distally with denticulate margin, up to 320 µ m long, rosettes up to 104 µ m long; introvert with some rosettes up to 48 µ m long; peri-oral region with tentacle-like rods and rosettes; anal ossicles tube foot endplates and support rods, tentacle-like rods, rosettes, 5 scales comprising base up to 320 µ m wide with digitiform column up to 360 µ m long, base and column comprising massed short branched rods.

Specimen 4 mm long with radial tube feet; cucumariid ring lacking posterior prolongations; mid-body ossicles typical solid 4-pillared tables, some margins closely denticulate, rare larger irregular tables with discs up to 120 µ m wide.

Colour (preserved). Body off-white with close grey-brown/ black flecking creating dark grey/black appearance, body sometime red-brown to orange, not darker orally and anally; tube feet off-white, sometimes red; tentacle branches dark brown, white lumps (rosette ossicle clusters) on trunks.

Distribution. St. Vincent Gulf (South Australia) to Cliff Head (100 km S of Geraldton) (Western Australia), intertidal and offshore sediments, seagrass beds, 0– 2 m.

Remarks. Specimen SAM K1374 is judged here (and so reported by Rowe and Gates 1995) to be the holotype for Phyllophorus ventripes Joshua and Creed, 1915 . Thus specimens of Phyllophorus ventripes SAM K1375 (labelled “type material”) and NMV F45143 (3 specimens labelled “ syntypes ”, and so reported by Smith 1970) are judged here to be paratypes. Rowe and Gates 1995 listed four paratype specimens of Phyllophorus ventripes in lot SAM K1375. We found only one specimen in this lot. The three missing specimens may be those registered as syntypes ( NMV F45143). We examined these SAM and NMV type specimens. The holotype of Phyllophorus ventripes Joshua and Creed, 1915 and the three NMV paratypes are conspecific with Thyone vercoi Joshua and Creed, 1915 , described in the same paper and based on a single specimen (see below under Phyllostauros vercoi ). The remaining SAM K1375 paratype of Phyllophorus ventripes is conspecific with Phyllophorus thyonoides H. L. Clark, 1938 .

There are no labels or other records of where and when Dr. J. C. Verco collected the specimens for which Thyone vercoi and Phyllophorus ventripes were erected as new species. However H. L. Clark 1938 records Le Fevre Peninsula (sandy shallows 15 km NW of Adelaide in Gulf St. Vincent) as the precise locality for the collection of two loan specimens of Thyone vercoi (information presumably pers. comm.). Apart from the original specimens collected by Dr. Verco there are no other SAM specimens of either of these two species. WAM specimens of P. thyonoides collected from sea grass beds and the sandy Le Fevre Peninsula provide evidence of the econiche for both P. thyonoides and P. vercoi .

The drawing of the calcareous ring for Phyllophorus ventripes Joshua and Creed, 1915 ( P. thyonoides and P. vercoi here) is somewhat misleading as it shows posterior prolongations arising from the radial plates only, whereas in many specimens they arise jointly from radial and inter-radial plates. H. L. Clark 1938 noted for Phyllophorus thyonoides “obviously the lines of division between radial and inter-radial pieces of the calcareous ring are indefinite and arbitrary”. We agree. We noted that in one specimen of Phyllophorella thyonoides ( WAM Z31975, illustrated in fig. 13f) the posterior prolongations of the calcareous ring are joined as in genus Massinium Samyn and Thandar, 2003 species (see below).

The dorsal tube feet are deeply buried in pits for Phyllophorus ventripes paratype SAM K1375 ( P. thyonoides here), and this presumably led the original authors to describe the species as lacking tube feet dorsally.

Figures

Figure 9. Photos of preserved specimens of Phyllophorella thyonoides (H. L. Clark, 1938). a, specimen from Western Australia (AM J21716); b, calcareous ring with posterior prolongations from radial plate only (AM J21716); c, specimen from South Australia (SAM K2597); d, calcareous ring with posterior prolongations jointly from radial and inter-radial plates (paratype of Phyllophorus ventripes Joshua and Creed, 1915, SAM K1375).

Figure 10. SEM images of ossicles from specimen of Phyllophorella thyonoides (H. L. Clark, 1938) (AM J21716). Tentacle rods, some dumbbellshaped, and rosettes (top); mid-body wall tables and tube foot endplate and support plate ossicle (bottom).

Figure 13. Photos of preserved specimens. a, Massinium melanieae O’Loughlin sp. nov. (holotype NMV F174897); b, Massinium vimsi O’Loughlin sp. nov. (holotype, NMV F76629) (insert: form of the calcareous ring plates); c, Massinium watsonae O’Loughlin sp. nov. (holotype, NMV F97435); d, calcareous ring, stone canal (along alimentary canal) and madreporite, and 2 polian vesicles (top left corner) of Massinium watsonae (TMAG H1988); e, colour morph of Massinium watsonae (NMV F174899) (insert: form of the calcareous ring plates); f, exceptional calcareous ring from specimen of Phyllophorella thyonoides (H. L. Clark, 1938) with posterior prolongations joined as in Massinium species (WAM Z31975) (insert: form of the calcareous ring plates).