Opisthocheiridae
Opisthocheiridae is a family of millipedes belonging to the order Chordeumatida. These millipedes range from 5 mm to 16 mm in length and are found from Belgium to Morocco. Adult millipedes in this family have 26 or 30 segments (counting the collum as the first segment and the telson as the last). This family includes the cave-dwelling species Opisthocheiron canayerensis, notable as one of few chordeumatidan species with only 26 segments. The adult female of this species has only 42 pairs of legs, and the adult male has only 40 leg pairs, as one would expect for adult chordeumatidans with four fewer segments than typically found in this order. Genera: Brachytropisoma Silvestri, 1898 Ceratosphys Ribaut, 1920 Fuentea Brölemann, 1920 Haplosphys Ribaut, 1920 Hispaniodesmus Verhoeff, 1910 Hispaniosoma Ribaut, 1913 Marquetia Ribaut, 1905 Marquetiella Jeekel, 1969 Opisthocheiron Ribaut, 1913 Proceratosphys Mauriès & Vicente, 1977 Sireuma Reboleira & Enghoff, 2014 References Chordeumatida