Millotauropus

Millotauropus is a genus of pauropods in the monotypic family Millotauropodidae in the monotypic order Hexamerocerata. The order Hexamerocerata includes only eight species and was created in 1950 to contain the newly discovered genus Millotauropus, which was found to have so many distinctive features as to warrant placement in a separate order. Before the discovery of Millotauropus, for example, pauropods were thought to have no more than ten leg pairs, but adults in the order Hexamerocerata have eleven pairs of legs.

Description
Pauropods in the order Hexamerocerata are characterized by telescopic antennae with six stalk segments, unlike all other pauropods (those comprising the larger order Tetramerocerata), which have antennae that are not telescopic and have only four stalk segments as adults. Adults in the order Hexamerocerata also feature a trunk with twelve entire tergites, whereas all other adult pauropods have trunks with six (entire or divided) tergites. Adults in the order Hexamerocerata have eleven pairs of legs, whereas other adult pauropods have eight to ten leg pairs. Furthermore, pauropods in the order Hexamerocerata have tracheae on the bases of their first pair of legs, a feature absent in all other pauropods.

Development
Pauropods in the order Hexamerocerata go through a process of post-embryonic development that differs from that of most pauropods. Like most pauropods, those in this order go through five stages from the first instar to the adult. Juveniles in this order, however, begin with six pairs of legs, nine trunk segments, and eight tergites and then become adults with eleven leg pairs, eleven trunk segments, and twelve tergites. Species in this order have six pairs of legs in the first stage, then eight pairs in the second, nine pairs in the third, ten pairs in the fourth, and finally eleven pairs in the fifth (adult) stage. Most other juvenile pauropods instead begin with three pairs of legs, seven trunk segments, and three tergites, then become adults with nine leg pairs, twelve trunk segments and six tergites, going through stages with three, five, six, eight, and nine pairs of legs.

Distribution
The order Hexamerocerata has a mainly tropical distribution, with species found in Brazil, tropical continental Africa, Madagascar, and Seychelles, but this order has also been found in Japan.

Species
The order Hexamerocerata includes the following species:


 * Millotauropus acostae Scheller, 1997
 * Millotauropus angustiramosus Remy, 1955
 * Millotauropus frustatorius Remy, 1959
 * Millotauropus hebetisetosus Remy, 1953
 * Millotauropus latiramosus Remy, 1953
 * Millotauropus machadoi Remy, 1953
 * Millotauropus silvestrii Remy, 1953
 * Millotauropus temporalis (Hüther, 1968)