Centipedes and bristlestails

The largest extant centipede
is Scolopendra (Figs 1, 2). Centipedes are often lumped with millipedes in the clade Myriapoda.

No pointed telson is present in centipedes,
but Lewis 2008 indicates the rear-most body segment, posterior to the genital openings and bearing two anal valves, is the telson (red in figure 1).

Shear and Edgecomb 2010 wrote:
“We review issues of myriapod phylogeny, from the position of the Myriapoda amongst arthropods to the relationships of the orders of the classes Chilopoda and Diplopoda. The fossil record of each myriapod class is reviewed, with an emphasis on developments since 1997. Stem-group myriapods are unknown, but evidence suggests the group must have arisen in the Early Cambrian, with a major period of cladogenesis in the Late Ordovician and early Silurian. Large terrestrial myriapods were on land at least by mid-Silurian.”

Rehm et al. 2014 wrote:
“Myriapods had been considered closely allied to hexapods (insects and relatives). However, analyses of molecular sequence data have consistently placed Myriapoda either as a sister group of Pancrustacea, comprising crustaceans and hexapods, and thereby supporting the monophyly of Mandibulata, or retrieved Myriapoda as a sister group of Chelicerata (spiders, ticks, mites and allies).

In addition, the relationships among the four myriapod groups (Pauropoda, Symphyla, Diplopoda, Chilopoda) are unclear.

To resolve the phylogeny of myriapods and their relationship to other main arthropod groups, we collected transcriptome data… Bayesian analyses robustly recovered monophyletic Mandibulata, Pancrustacea and Myriapoda.

Molecular clock calculations suggest an early Cambrian emergence of Myriapoda ∼513 million years ago and a late Cambrian divergence of myriapod classes. This implies a marine origin of the myriapods and independent terrestrialization events during myriapod evolution.”

At this point it is appropriate to introduce the sea bristletail,
Petrobius maritimus (Fig. 2, 1.5cm), found along the perimeter of the British Isles. Perhaps this taxon is close to that marine origin and terrestrialization of myriapods, like the centipede, Scolopendra (Fig. 1).

As before,
all arthropod taxa with a telson appear to be derived from a previously omitted clade of trilobites with a telson. Following the tenets of monophyly, trilobites are not extinct.

References
Lewis JGE 2008. The Biology of Centipedes (Digitally printed 1st paperback version. ed.). Cambridge: Cambridge University Press.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Rehm P et al. 2014. Phylogenetic position of Myriapoda revealed by 454 transcriptome sequencing. Mol Phylogenet Evol 2014 Aug;77:25-33. doi: 10.1016/j.ympev.2014.04.007.
Shear WA and Edgecombe GD 2010. The geological record and phylogeny of the Myriapoda. Arthropod Struct Dev. 2010 Mar-May;39(2-3):174-90. doi: 10.1016/j.asd.2009.11.002. Epub 2009 Dec 6.

https://en.wikipedia.org/wiki/Myriapoda
https://en.wikipedia.org/wiki/Telson
https://www.nhm.ac.uk/discover/news/2019/september/centipedes-evolved-complex-venom-five-times.html
https://en.wikipedia.org/wiki/Scolopendra