Subgenus Biannulata Samaai, Gibbons & Kelly, 2006

Type species. Latrunculia kaakaariki Alvarez, Bergquist and Battershill, 2002 .

Diagnosis. Latrunculia species in which the anisodiscorhabd microscleres have only two distinct whorls of projections around the shaft, the median and subsidiary whorls, between the undifferentiated manubrium and basal whorl, and the undifferentiated apical whorl and apex. The manubrium and basal whorl are indistinguishable, forming a cuff of irregularly distributed spines that are themselves lightly and irregularly spined. The apical whorl and apex are also indistinguishable, forming a tuft of irregularly distributed spines that are smooth or lightly and irregularly spined. The whorls are frequently composed of robust spines that are themselves lightly and irregularly spined, the primary spines are arranged horizontally around the shaft and may be grouped into sectors. The megascleres may be lightly and irregularly spined along the shaft (after Samaai et al. 2012).

Remarks. Fig 1 B illustrates the diagnostic microscleres that define subgenus Biannulata . Figure 16 Q–AF illustrate the diagnostic anisodiscorhabds for living species of the subgenus Latrunculia (Biannulata) .