Pseudocolochirus axiologus (H. L. Clark, 1914 )

O’Loughlin, P. Mark, Harding 1, Caroline & Paulay, Gustav, 2016, The sea cucumbers of Camden Sound in northwest Australia, including four new species (Echinodermata: Holothuroidea), Memoirs of Museum Victoria 75, pp. 7-52 : 30

Pseudocolochirus axiologus (H. L. Clark, 1914)

Table 1 ; appendix 1; figures 15, 16

Colochirus axiologus H. L. Clark, 1914: 171–173 , pl. 25.— Ekman, 1918: 26–28, pl. 2 fig. 1, pl. 3 figs 16–19.

Pseudocolochirus axiologus (H. L. Clark, 1938) : 456–457.— 1946: 394.

Pseudocolochirus violaceus ( Théel, 1886) .— Cherbonnier, 1988: 174–177, figs 73, 74 (part; N Australia specimens are P. axiologus ).— Rowe (in Rowe & Gates), 1995: 280 (part; N Australia specimens are P. axiologus ).

Material examined. Northwest Western Australia, Kimberley Region , Camden Sound, WAMSI 1.1 .1, RV Solander , sled, site no LIN_35, WAM station no 23, barcode 10000760, from -15.363088 124.44389 37 m to -15.362756 124.443995 37 m, 17 Mar 2015, WAM Z89031 (1) ; RV Solander , sled, site no SOL_49, WAM station no 32, barcode 10002389, from -15.668951 124.357909 41 m to -15.669007 124.357529 42 m, 22 Mar 2015, WAM Z89032 (1).

WA, northwest shelf, -12.84 125.68 88-97 m, 2 Apr 1981, NMV F112187 (1); -12.90 125.58 84-88 m, 2 Feb 1981, NMV F112188 (2); -12.90 125.59 83 m, 2 Apr 1981, NMV F112189 (2); -12.83 125.7 91 m, 1 Apr 1981, NMV F112190 (1).

Northern Territory, Joseph Bonaparte Gulf, -11.54 129.82 60 m, 12 Sep 2009, NMV F202986 (1) (tissue code MOL AF 1512 ) ; -10.31 129.62 89 m, 1 Sep 2009, NMV F202987 (1) (tissue code MOL AF 1504 ) ; -11.01 129.79 55 m., 6 Sep 2009, NMV F202988 (2) (tissue code MOL AF 1507 ) .

Queensland, Gulf of Carpentaria, -11.37 141.42 35 m, 9 Sep 1982, NMV F95259 (1) (tissue code MoV 4627).

Remarks. H. L. Clark (1914) noted the following features for the type of his Colochirus axiologus :

1. 90 mm axial (horizontal) length;

2. tube feet confined to ventral ambulacra;

3. absence of ossicles in the body wall;

4. bright purple colour around the tentacle aperture;

5. body colour purplish-rose.

When describing additional specimens, H. L. Clark (1938) referred his species to Pseudocolochirus Pearson, 1910 , and confirmed the absence of tube feet other than on the ventral ambulacra, and the absence of ossicles in the body wall. H. L. Clark (1938) acknowledged that Ekman (1918) found and illustrated distinctive ossicles in the body wall of small specimens (41–49 mm long) of what he judged to be Colochirus axiologus , and Clark concluded that ossicles disappear with increase in size of specimens.

We examined a small specimen (40 mm axial preserved length) from Joseph Bonaparte Gulf (NMV F202988) that lacked ossicles in the mid-body wall but did have a few almost inconspicuous tube feet on the dorsal anterior radii (that H. L Clark 1938 had also noted on his specimens). We also found endplate support rod-plates in the ventral tube feet, and distinctive small thick plates in the nearby body wall with very small to no perforations. These ossicles were frequently dumbbell-shaped and lacked perforations, or had up to three very small ones. The plates varied in size from 40–90 µm long. We found similar small plates near the ventral tube feet in a larger specimen (100 mm axial preserved length) from Camden Sound (WAM Z89032). These buttons were larger, up to 200 µm long, and more irregular in form. There were a few anterior dorsal radial hard papillae in which we found multi-layered ossicles fragments, and large single-layered perforated plate fragments up to 440 µm long.

We judge that the specimens examined by H. L. Clark (1914, 1938), Ekman (1918) and us are conspecific and belong to Pseudocolochirus axiologus (H. L. Clark, 1914) . We acknowledge that this species is similar to Pseudocolochirus violaceus ( Théel, 1886) . We do not accept the synonymy of these two species by Cherbonnier (1988). Pseudocolochirus violaceus has the following differing characters:

1. the whole body, both radial and inter-radial, is covered with small papillae;

2. tube feet are clearly evident on the dorsal radii;

3. the distinctive plates are present in the mid-body wall;

4. prominent anterior and posterior papillae are more numerous.

We raise Pseudocolochrus axiologus (H. L. Clark, 1914) out of synonymy (by Cherbonnier 1988) with Pseudocolochirus violaceus ( Théel, 1886) . Rowe (in Rowe & Gates, 1995) followed Cherbonnier (1988) who considered all Pseudocolochirus species to be synonyms, with Pseudocolochirus violaceus the senior synonym. We judge that northern Australian specimens are Pseudocolochirus axiologus , not P. violaceus (see synonymy above).

Family Phyllophoridae Östergren, 1907 (sensu Pawson & Fell 1965)