Figure 8.9 This male pycnogonid Of the species Boreonymphon robustum is covered with his offspring, whom he is carrying.

A cephalothorax and much smaller abdomen make up the extremely reduced body of the pycnogonid, which has up to two pairs of dorsally located simple eyes on its non-calcareous exoskeleton, though sometimes the eyes can be missing, especially among species living in the deep oceans.

All pycnogonid species have separate sexes except for one species that is hermaphroditic.

Other marine fauna, such as actinostolid sea anemones (family Actinostolidae), crabs in the genus Kiwa, and the pycnogonid arthropod or "sea spider" cf. Sericosura, can be found living together with this species.