Paracucumidae Pawson and Fell, 1965

O’Loughlin, P. Mark, Mackenzie, Melanie, Paulay, Gustav & VandenSpiegel, Didier, 2014, Four new species and a new genus of Antarctic sea cucumbers with taxonomic reviews of Cladodactyla, Pseudocnus, Paracucumidae and Parathyonidium (Echinodermata: Holothuroidea: Dendrochirotida), Memoirs of Museum Victoria 72, pp. 31-61 : 51

Family Paracucumidae Pawson and Fell, 1965

Key 2; figure 12

Diagnosis. Body cylindrical, posterior taper; body wall thin; tube feet distributed around body; 10–15 dendritic or sub-digitiform tentacles, ventral pair usually small; mid-body wall ossicles perforated plates, some with knobs, some with secondary layer developments from one or a few layers to dome-like stacks or spines, sometimes in cross form.

Included genera. Paracucumis Mortensen, 1925b ; Crucella Gutt, 1990

Remarks. Gutt (1990) referred his new genus Crucella to the Paracucumidae , and O’Loughlin (2002) and O’Loughlin et al. (2009b) maintained this referral. O’Loughlin et al. (2009b) discussed Crucella , judged that Caespitugo citriformis Gutt, 1990 is a junior synonym of Thyone scotiae Vaney, 1906 and referred Thyone scotiae to Crucella . Currently the family has three recognized species: Paracucumis turricata ( Vaney, 1906) (junior synonym Paracucumis antarctica Mortensen, 1925b by O’Loughlin 2002), Crucella scotiae ( Vaney, 1906) , and Crucella hystrix Gutt, 1990 . We add a fourth species Crucella susannae O’Loughlin sp. nov. Phylogenetic analysis based on CO1 sequence data recovers a monophyletic Paracucumidae among 200 species of dendrochirotids sequenced to date, but shows Crucella , as currently defined, to be paraphyletic ( Fig. 12 ), with C. scotiae sister to the new species C. susannae and P. turricata sister to these two species. However P. turricata has what we judge to be two significant morphological characters (up to 15 tentacles and body wall plates imbricating or contiguous) that are not shared with C. scotiae and C. susannae . We acknowledge this anomaly for generic assignment, but on primarily morphological grounds maintain Thyone scotiae in Crucella and maintain Paracucumis as a monotypic genus. CO1 data indicate further cryptic, geographical divergence within C. hystrix and C. scotiae as previously indicated by O’Loughlin et. al. (2010). We note in relation to the 2010 paper and relevant tree (page 8) that the South Shetland specimen (green) of C. scotiae is re-identified here as our new species C. susannae .

Figures

Figure 12. Maximum likelihood tree for Paracucumidae, based on COI sequences, GTR+G model, 100 bootstrap replicates, Psolidium tenue as outgroup. Filled circles>0.95 bootstrap support.