Ophiomusium Lyman, 1869

Stöhr, Sabine, 2011, New records and new species of Ophiuroidea (Echinodermata) from Lifou, Loyalty Islands, New Caledonia, Zootaxa 3089, pp. 1-50 : 45

Ophiomusium Lyman, 1869

Figure 21

Remarks. Ophiomusium is a moderately large genus with 72 described species ( Stöhr & O'Hara 2007), but many of them are morphologically similar and difficult to identify. They present a juvenile appearance with few disk plates, wide, block-like mouth papillae, absence of ventral and dorsal arm plates beyond a few proximal arm joints, and tentacle pores restricted to proximal joints or not obvious on the distal arm. The arm spines are usually few and shorter than an arm joint. The position of the second tentacle pore inside the mouth slit is however not a juvenile character. Four species, previously unknown from New Caledonia, have been identified from Lifou ( Table 2). Among them, O. relictum Koehler, 1904 has a conspicuously rough appearance, with tuberculous plates on disk and arms. Ophiomusium scalare Lyman, 1878 has numerous, tumid disk scales and arm plates. As Koehler (1922) remarked, O. morio Koehler, 1922 is similar to O. simplex Lyman, 1878 , but distinguished by fewer disk scales and lack of small plates between oral shield and the large ventral interradial plate.

Figures

FIGURE 21. SEM images of species of Ophiomusium. A – C, O. relictum, A, dorsal aspect, B, ventral aspect, C, arm in lateral view. D – F, O. luetkeni, D, dorsal aspect, E, ventral aspect, F, arm in lateral view. G – I, O. scalare, G, dorsal aspect, H, ventral aspect, I, arm in lateral view. Scale bars in millimetre.