Spirostreptidae Brandt, 1833

Enghoff, Henrik, 2023, A new distinct, disjunct giant millipede of the genus Spirostreptus Brandt, 1833, from Tanzania, and a solution for orphaned Spirostreptus species (Diplopoda, Spirostreptida, Spirostreptidae), Zootaxa 5389 (2), pp. 275-287 : 276

Family Spirostreptidae Brandt, 1833

Although the family Spirostreptidae as such is quite well-defined and morphologically coherent, dividing it into subfamilies and/or tribes has always been challenging. Traditionally, three subfamilies/tribes have been recognized:

- Spirostreptinae/-ini Brandt, 1833

- Trachystreptinae/-ini Cook in Cook & Collins, 1895

- Triaenostreptinae/-ini Attems, 1914

Hoffman (1980) in his classification of Diplopoda discussed the problems with this subdivision and simply listed all spirostreptid genera alphabetically.

Independently of this, Krabbe (1982) added:

- Metriostreptini Krabbe, 1982

- Orthogoneptini Chamberlin, 1941

When Hoffman et al. (2001) synonymized Triaenostreptus Attems, 1914 under Spirostreptus, Triaenostreptinae /-ini became a synonym of Spirostreptinae/-ini which left the genera until then classified in Spirostreptinae/-ini “homeless”. The oldest available family-group name based on one of these genera is Perustreptinae Verhoeff, 1941 (see Jeekel 1970). Considering the blatant paucity of phylogenetic studies on Spirostreptidae , in particular studies involving molecular data ( Nielsen et al. 2022), it makes no sense to distinguish between the subfamily and tribe levels for the time being, and I suggest a preliminary subdivision of Spirostreptidae into five co-ordinate taxa, here (arbitrarily) listed as tribes in alphabetical order:

- Metriostreptini Krabbe, 1982 (two African genera)

- Orthogoneptini Chamberlin, 1941 (two American genera)

- Perustreptini Verhoeff, 1941 , syn. Spiropstretini sensu auctorum, nec Brandt, 1833 (many African and most American genera)

- Spirostreptini Brandt, 1833 , syn. Triaenostreptini , Attems, 1914 (several African genera)

- Trachystreptini Cook, 1895 (several African genera)

With the probable exception of Spirostreptinae (see below), and the possible exceptions of the small taxa Metriostreptinae and Orthogoneptinae, the monophyly of the tribes is more than dubious. The status of Trachystreptini has been quite extensively debated, most recently by Enghoff et al. (in press), and this taxon will almost certainly not “survive” a molecular phylogenetic analysis. It also appears quite possible that one or more of the preliminary tribes will turn out to occupy subordinate position within Perustreptini as here delimited.