Millipede phylogeny revisited in the light of the enigmatic order Siphoniulida

Abstract

The discovery of six specimens of the enigmatic order Siphoniulida, including for the first time males, prompted a modern re‐analysis of current phylogenetic schemes for the class Diplopoda derived from traditional morphological and developmental characters. The data matrix was constructed and analysed using paup. The resulting phylogenetic hypotheses corroborated the longest standing, traditional classification, but also demonstrated clearly that more characters must be included to reach a better resolution. Recent alternative phylogenetic hypotheses and classifications are discussed in the light of the current analysis. The validity of a putative helminthomorph synapomorphy, the location of male gonopods on the 7th body ring, is discussed. Scanning electron microscopy corroborated morphological characters already described for the Siphoniulida: modified anterior legs, an apparently legless 3rd body ring, pyriform head, antennae with clavate setae, and absence of ozopores. The highly modified gonopods of the Siphoniulida are described for the first time; only the anterior legs of the 7th ring are modified into gonopods, the posterior legs of this ring are developed as normal walking legs. The gnathochilarium differs from the Colobognatha and consists of well‐developed stipites with palps, elongated lingual plates with palps and a narrow central sclerite, most likely the mentum. Structures on the epiproct may possibly be spinnerets. Despite the discovery of adult males, the Siphoniulida are still considered Helminthomorpha incertae sedis .

Complete mitochondrial genomes of two flat-backed millipedes by next-generation sequencing (Diplopoda, Polydesmida)

“…Polydesmida also unite the Nematophora (including Stemmiulida, Callipodida and Chordeumatida) as sister group for the shared presence of preanal spinnerets (Enghoff 1984; Sierwald et al 2003; Shear 2008; Blanke and Wesener 2014). The Polydesmida allied with Platydesmida (basal representatives of the subclass Colobognatha) as a clade in our phylogenetic analyses.…”

Arthropod Phylogenetics in Light of Three Novel Millipede (Myriapoda: Diplopoda) Mitochondrial Genomes with Comments on the Appropriateness of Mitochondrial Genome Sequence Data for Inferring Deep Level Relationships

“…Sierwald and Bond [6] represents the first attempt to reconstruct diplopod ordinal relationships using a total evidence approach by combining the molecular dataset of Regier and Shultz [17], [18] with a morphological matrix from Sierwald et al . [19]. Pitz and Sierwald [13] investigated the familial relationships within the order Spirobolida.…”

Exploring phylogenomic relationships within Myriapoda: should high matrix occupancy be the goal?

“…Colobognatha and Eugnatha were originally proposed in the classical era of myriapod systematics (Attems 1926;Verhoeff 1928), but were discarded in the influential millipede classification by Hoffman (1980), who considered that the characteristic reduced mouthparts of Colobognatha were prone to convergence. They have, however, consistently been endorsed in cladistic analyses (Enghoff 1984;Sierwald et al 2003;Blanke and Wesener 2014). As likewise found by Brewer and Bond (2013), Eugnatha includes two groups that have a long history of usage in morphologybased systematics.…”

“…Both of these conflict with the weak morphological support for Spirobolida and Julida as closest relatives (Blanke and Wesener 2014), but have been found in other molecular studies. A Julida + Spirostreptida clade was supported by three nuclear protein-coding genes (Miyazawa et al 2014), whereas nuclear ribosomal genes (Cong et al 2009) and mitochondrial gene rearrangements and amino acid sequences (Woo et al 2007 (Enghoff et al 1993) or as sister group to a putative clade named Nematophora (Sierwald et al 2003;Blanke and Wesener 2014). The latter group, named for the shared presence of preanal spinnerets, traditionally includes Stemmiulida, Callipodida and Chordeumatida (Enghoff 1984;Sierwald et al 2003).…”