Appendix on comparative morphology of Knebelia species.

This table shows all characters used in the description of the three recognized species of Knebelia Van Straelen, 1922: Knebelia bilobata (Münster, 1839), the type species; Knebelia schuberti (Meyer, 1836); Knebelia totoroi Audo, Schweigert & Charbonnier, in press. Data comes from samples preserved in collections of Bayerische Staatssammlung für Paläontologie und historische Geologie (Munich, Germany), Jura-Museum (Eichstätt, Germany), 2Staatliches Museum für Naturkunde (Stuttgart, Germany), Museum national d'Histoire naturelle (Paris, France), Natural History Museum (London, United Kingdom) and Sedgwick Museum of Earth Sciences - Cambridge University (Cambridge, United Kingdom)

Surface models of all specimens investigated herein.

<p><i>Peltogaster</i> spp. infesting different hermit crabs (A, C, F, H), <i>Sylon</i> spp. infesting <i>Pandalina brevirostris</i> (B, D, E, G, I). Color-markings: host = grey, rhizocephalan externa = blue, rhizocephalan interna = yellow, rhizocephalan eggs = turquoise, rhizocephalan visceral mass = green. Not to scale. (A) <i>P</i>. <i>boschmai</i> with detail of respective externa. (B) <i>S</i>. <i>hippolytes</i> specimen 2b with detail of respective externa. (C) <i>Peltogaster</i> sp. 1 with detail of respective externa. (D) <i>S</i>. <i>hippolytes</i> specimen 2a with detail of respective externa. (E) <i>S</i>. <i>hippolytes</i> specimen 1c with detail of respective externa. (F) <i>Peltogaster</i> sp. 2 with detail of respective externa. (G) <i>S</i>. <i>hippolytes</i> specimen 1a with detail of respective externa. (H) Externa of <i>P</i>. <i>curvata</i>. (I) <i>S</i>. <i>hippolytes</i> specimen 1b.</p

Ratio of the volumes of the surface models of the rhizocephalans externa, visceral mass, and the host.

<p>The following parameters are results for four individual specimen of <i>Peltogaster</i> and five individual specimen of <i>Sylon</i>, therefore, no error estimate is possible for each individual.</p

Macro-photograph, surface model and volume rendering of <i>Sylon hippolytes</i> infesting <i>Pandalina brevirostris</i> (specimen 1b).

<p>Color-markings: <i>P</i>. <i>brevirostris</i> = grey, nervous system (n) of <i>P</i>. <i>brevirostris</i> = pink, interna (i) of <i>S</i>. <i>hippolytes</i> = yellow, externa (e) of <i>S</i>. <i>hippolytes</i> = blue, eggs of <i>S</i>. <i>hippolytes</i> = turquoise, visceral mass of <i>S</i>. <i>hippolytes</i> = green. (A) Macro-photograph. Scale = 1 mm. (B) Surface model. (C) Detail of volume rendering. (D) Same as C with corresponding surface model.</p

Scatter plots with trend lines of correlations between volume measurements of different parts of the parasite and the host.

<p>x = <i>Sylon</i> spp., + = <i>Peltogaster</i> spp., au = artificial units, the trend lines were computed by least-square linear regression. (A) Volume of parasite’s externa and volume of host. (B) Volume of parasite’s egg mass and volume of host. (C) Volume of parasite’s egg mass and volume of parasite’s externa. (D) Volume of parasite’s visceral mass and volume of parasite’s externa. (E) Parasite’s estimated egg number and volume of parasite’s egg mass. (F) Volume of parasite’s visceral mass and volume of parasite’s egg mass.</p

Reconstructed relationship of Rhizocephala with outgroup Thoracica after [1, 5].

<p>Note the paraphyly of “Kentrogonida” with a monophyletic Akentrogonida. For further information, please follow the discussion in [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0179958#pone.0179958.ref001" target="_blank">1</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0179958#pone.0179958.ref005" target="_blank">5</a>].</p

Ratio of the volumes of the surface models of the rhizocephalan parasite, externa, interna and the host.

<p>The following parameters are results for one individual of each species, therefore, no error estimate is possible.</p