Helminthomorpha, Pocock, 1887

Shelley, Rowland M. & Golovatch, Sergei I., 2011, Atlas of Myriapod Biogeography. I. Indigenous Ordinal and Supra-Ordinal Distributions in the Diplopoda: Perspectives on Taxon Origins and Ages, and a Hypothesis on the Origin and Early Evolution of the Class, Insecta Mundi 2011 (158), pp. 1-134 : 21

Infraclass Helminthomorpha (Fig. 2, 14)

The distribution of Helminthomorpha ( Fig. 14) is nearly identical to that of Chilognatha ( Fig. 5), to which readers are referred for details, as Pentazonia barely impact the latter’s range; the New World, Eurasian, sub-Saharan African, and oceanic occurrences are identical. The only difference, barely perceptible, is in coastal Western Australia, where Helminthomorpha do not extend quite as far eastward along the southern coast. Most helminthomorph occurrences are attributable to Eugnatha ( Fig. 24); Colobognatha ( Fig. 15) have minimal impact and are largely subsumed within the former’s area. Colobognatha extend Helminthomorpha westward in the Atlantic to encompass St. Helena and north of the Arctic Circle in Asian Russia; otherwise, helminthomorph distribution is attributable to Eugnatha alone.

Archidesmus macnioli Peach, 1887 , the earliest helminthomorph fossil ( Fig. 1, 5, 14, upright triangle), from Silurian deposits in Scotland, came from either Avalonia itself or Laurentia after it collided with Baltica+Avalonia. It is not definitely assignable to either a modern or an extinct order.