Massinium

P. Mark O’Loughlin, Melanie Mackenzie & Didier Vandenspiegel, 2014, New dendrochirotid sea cucumbers from northern Australia (Echinodermata: Holothuroidea: Dendrochirotida), Memoirs of Museum Victoria 72, pp. 5-23 : 12

Key to the species of Massinium

1. Ossicles present in the mid-body wall 2

— Mid-body wall lacking ossicles 9

2. Mid-body wall with table ossicles of some form present 3

— Mid-body wall lacking any form of table ossicles 6

3. Mid-body wall ossicles tables only 4

— Mid-body wall ossicles tables and additional ossicle forms 5

4. Peri-oral table spires well developed, typically with long, splayed, pointed apical spines M. bonapartum sp. nov. (NW Australia)

— Peri-oral table spires frequently absent or reduced, few short apical spines M. keesingi sp. nov. (NW Australia)

5. Mid-body with rare but developed table ossicles; tentacles with table ossicles; up to 2 polian vesicles M. dissimilis (Madagascar)

— Mid-body with reduced table ossicles; tentacles with rosettes only; typically 4 polian vesicles M. magnum (Indonesia)

6. Mid-body wall with rosettes present 7

— Mid-body wall lacking rosettes 8

7. Introvert table discs irregular with predominantly 4 central perforations and single ring of smaller outer perforations; tentacles with rods and rosettes M. maculosum (South Africa)

— Introvert table discs irregular with predominantly 4 central perforations and up to 3 rings of smaller outer perforations; tentacles with elongate rod-rosettes M. albicans (New Caledonia)

8. Mid-body ossicles predominantly short, thick, irregular, rarely perforate, granuliform rods; tentacles with rosette ossicles only M. granulosum . (NE Australia)

— Mid-body ossicles predominantly U-shaped, distally perforate rods; tentacles with rod ossicles only M. arthroprocessum (South Africa)

9. Large and small tube feet uniformly distributed; 4 polian vesicles; peri-anal body wall with table ossicles Massinium melanieae (Great Australian Bight)

— Tube feet not uniformly distributed; fewer than 4 polian vesicles; peri-anal body wall lacking table ossicles 10

10. Tube feet scattered dorsally, more prominent ventrally; peri-oral table discs with up to 20 perforations; tentacles with rods and rare rosettes Massinium vimsi (Bass Strait, SE Australia)

— Tube feet more concentrated along longitudinal muscles; peri-oral table discs with up to 40 perforations; tentacles with rare fine rods, lacking rosettes Massinium watsonae (SE Tasmania, Australia)