Metamastigophorophyllon
Metamastigophorophyllon is a genus of millipedes in the family Anthroleucosomatidae. This genus includes millipedes found in Azerbaijan, Iran, Russia, and Georgia. All five species in this genus have 31 segments in adults. This genus is notable for including the only species in the order Chordeumatida with 31 segments rather than the 30 segments usually observed in adults in this order.
Discovery and taxonomy
The Romanian zoologist Traian Ceuca first proposed Metamastigophorophyllon in 1976 as a subgenus within the genus Mastigophorophyllon in the family Mastigophorophyllidae. Ceuca proposed this monotypic subgenus to contain the species Mastigophorophyllon giljarovi, which was described by the Czech zoologist Jaroslav Lang in 1959 based on type material found near Krasnaya Polyana in Russia. Lang described this species as having 30 segments.In 1982, the French myriapodologist Jean-Paul Mauriès of the Muséum National d'Histoire Naturelle in Paris described the monotypic genus Persedicus and its type species Persedicus martensi based on specimens found in wet litter in dense forests in Mazandaran province in Iran. Mauriès placed this genus in the family Anthroleucosomatidae and described this genus and its type species as having 31 segments in adults of both sexes. This species was the first in the order Chordeumatida to be described with an odd number of segments in adults: Before the description of this species, adults in this order were known to have only 26, 28, 30, or 32 segments. This millipede remained the only chordeumatidan species described with 31 segments for more than three decades.
In 2016, the Serbian myriapodologists Dargan Ž. Antić and Slobodan E. Makarov of the University of Belgrade described three new species in the genus Metamastigophorophyllon, all with 31 segments in adults, and all found in the Caucasus: M. hamatum, M. lamellohirsutum, and M. torsivum. Furthermore, Antić and Makarov redescribed Metamastigophorophyllon giljarovi based on a large sample of specimens, finding that this species has 31 segments in adults and moving this species to the family Anthroleucosomatidae. Moreover, Antić and Makarov deemed Persedicus to be a junior synonym of Metamastigophorophyllon, and authorities now consider Metamastigophorophyllon martensi to be the valid name for the species described by Mauriès.
Description
Adults in this genus have 31 segments, one segment more than usually observed in adults in the order Chordeumatida. Accordingly, adult females in this genus have 52 pairs of legs, two more than usually found in chordeumatidans. In males, the eighth and ninth leg pairs become gonopods in adults, leaving adult males with 50 pairs of walking legs, excluding the gonopods.Males in this genus range from 10 mm to 15 mm in length, whereas females range from 11 mm to 19 mm in length. In males, the five leg pairs in front of the gonopods are enlarged. The anterior gonopods have an especially distinctive shape, with a medial part and two lateral branches, one inner branch and one outer branch. The inner branch is subdivided into an anterior part and a posterior part. The shape of these gonopods distinguish this genus from the other genera in the family Anthroleucosomatidae.