Robbea judithae

Pröts, Philipp, Novotny-Diermayr, Veronica & Ott, Jörg A., 2024, A novel three-part pharynx and its parallel evolution within symbiotic marine nematodes (Desmodoroidea, Stilbonematinae), Organisms Diversity & Evolution 24 (3), pp. 353-373 : 357

Robbea judithae , R. lotti and R. weberae

The corpus is an ellipsoid, only very slightly tapering towards the anterior end. The orientation of the myofilaments is similar in all three species, being directed forward at the anterior end, changing gradually to perpendicular at mid-length and backward directed at the posterior end ( Fig. 1d, e ; Fig. 4d; Fig. 5f ; Fig. 7h , Fig. 8a ). Myofilaments are displaced at several positions providing space for nuclei in all three species ( Figs. 4b, d, 5d–f , 7c, d , 8c, e , 9a , 10c ).

Figures

Fig. 1 Pharynx musculature of Stilbonematinae, CLSM optical sections. Anterior on the left side. a Eubostrichus topiarius, b Paralaxus cocos, c Catanema schiemeri, d Robbea lotti, e Robbea weberae, f Rob- bea judithae, g Cyathorobbea hypermnestra, h Cyathorob- bea ruetzleri, i Cyathorobbea agricola, j Laxus oneistus. Scalebars 20 μm. ap, anterior pharynx; b, bulbus; bd, buccal dilator muscle; c, corpus; da, dorsal ampulla; gd, gland duct; i, isthmus; sp, spiral muscle; spm, somato-pharyngeal mus- cle; sm, somatic muscle

Fig. 5 Dorsal and subventral gland ampullae. Anterior on the left side. a Catanema schiemeri, CLSM optical section, autofluorescence, corpus, b Catanema schiemeri, TEM micrograph, corpus c Catanema schiemeri, CLSM micrograph, isthmus, musculature in orange, nuclei in blue d Robbea lotti, CLSM optical section, musculature in orange, nuclei in blue, corpus e Robbea weberae, CLSM optical section, musculature in orange, nuclei in blue, corpus f Robbea judithae, CLSM optical section, musculature in orange, nuclei in blue, corpus g Cyathorobbea hypermnestra, CLSM optical section, musculature in orange, corpus h Cyathorobbea hypermnestra, TEM micrograph, corpus i Cyathorobbea hypermnestra TEM micrograph, anterior isthmus j Cyathorobbea ruetzleri, CLSM optical section, musculature

Fig. 7 Pharyngeal region, pharynx nuclei, CLSM opti- cal sections. Colors: a–c, e, f: musculature in red/orange, nuclei in blue; d: musculature in blue, nuclei in magenta; nuclei within the orange labelled area/ outline are pharynx nuclei. For some species the outline of the pharynx is further indicated with white dashed lines. a Catanema schiemeri, b Robbea judithae, c Robbea lotti, d Rob- bea weberae, e Cyathorobbea hypermnestra, f Cyathorobbea ruetzleri, g Cyathorobbea agri- cola, h Laxus oneistus. Dashed lines indicate the outline of the pharynx. Scalebars 20 μm. en, elongated nucleus inside the pharynx; n, nucleus inside the pharynx; ne, epidermal nuclei

Fig. 8 Pharyngeal region, CLSM optical sections, dorsal and subventral ampullae, musculature in orange, nuclei in blue a, b Robbea weberae, c, d Robbea lotti, e Robbea judithae. Scalebars a, b, d, e 20 μm; c 10 μm. c, corpus; da, dorsal ampulla; gd, gland duct; i, isth- mus; va, subventral ampulla

Fig.9 Pharyngeal region, subventral ampullae. Musculature in orange, nuclei in blue a Robbea lotti, CLSM optical section b Robbea judithae, volume rendering c Robbea weberae, CLSM optical section. Scalebars 20 μm. b, bulbus; c, corpus; gd, gland duct; i, isthmus; n, nucleus; sm, somatic muscle; sp, spiral muscle; va, subventral ampulla

Fig. 10 3D Reconstructions of corpus nuclei, anterior on the right a Catanema schiemeri, b Cyathorobbea hypermnestra, c, d Robbea judithae. Scalebars a 10 μm, b 15 μm, c 20 μm, d 10 μm. c, corpus