Elisesione problematica
Creators: name: Jimi, Naoto
name: Eibye-Jacobsen, Danny
name: Salazar-Vallejo, Sergio I.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Phyllodocida
Hesionidae
Elisesione
Elisesione problematica

description: Elisesione problematica (Wesenberg-Lund, 1950)
(Figs 3-4)
Hesionella problematica Wesenberg-Lund, 1950: 14-15, fig. 15.
Wesenbergia problematica: Hartman 1955: 41.
Wesenbergia problematica: Pleijel 1998: 112-113, fig. 9.
Elisesione problematica: Salazar-Vallejo 2016: 3-5.
Description: Holotype about 50 mm long, 8 mm wide, 16 chaetigers. Body cylindrical, tapered in posterior region (Figs. 3A, B), brownish in ethanol, dorsal integument annulated, with 13- 15 transverse wrinkles per segment (Figs. 3A, B, C). Tentacular cirri, dorsal cirri and parapodial lobes whitish. Pigmentation of holotype unknown (specimens in ethanol for over 55 years before description; now darker).
© 2018 Academia Sinica, Taiwan
Prostomium wider than long, median line with a shallow depression, lateral margins rounded, wider medially (Fig. 3C). Eyes not seen. Palps and antennae present, damaged; palps ventral, slightly more lateral than antennae; left antenna present, tip damaged; right antenna missing (in the original illustration, palps and antennae tapered, of similar length). Tentacular cirri long, thick. Lateral cushions low, slightly projected laterally, divided in 2-3 parts (Figs. 3A, C).
Parapodia with chaetal lobes cylindrical, truncate, longer than wide (Fig. 4A); dorsal cirrophores cylindrical, smooth, about 4 / 5 times as long as wide (Fig. 4B). Ventral cirrophore cylindrical, smooth, as long as wide (Fig. 4C). Ventral cirri smooth, not reaching tip of neurochaetal lobe (as indicated in original illustration).
Acicula black, tapered; acicular lobe single, blunt, digitate. About 25 neurochaetae per bundle (Fig. 4D), shaft and blade pale brownish, blade 8-12 times as long as wide, with subdistal tooth as long as apical tooth, guard approaching apical tooth (Fig. 4E).
Posterior region tapered into a blunt cone; body wall macerated (Fig. 3B). Cirri of prepygydial segment broken; pygidium smooth, depressed; anus dorso-terminal, open, with two pairs of lateral anal cirri.
Pharynx smooth, partially everted, basal ring barely exposed, dorsal papilla not exposed, terminal papillae absent (Figs. 3A, C).
© 2018 Academia Sinica, Taiwan
Type material: Holotype (ZMUC-POL-480), sex unknown. Southwest off Iceland (555 m depth, 64°18'N, 27°00'W).
Distribution: Only known from the type locality, southwest off Iceland, 555 m depth.
Phylogenetic analysis
In the resulting tree, Elisesione, Hesione, and Leocrates are reciprocally monophyletic, with high support value (86% bootstrap support [BS]). Elisesione is sister to Leocrates, although they comprise a poorly supported clade (52% BS) (Fig. 5).
In a previous morphological study, Elisesione, Hesione, and Leocrates were monophyletic and regarded as tribe Hesionini (Pleijel 1998). Our results based on four genes also supported the tribe as monophyletic. In Pleijel’s paper, Elisesione is sister to Hesione; this is not in agreement with our results. However, the BS value of the clade is poor (52% BS); hence, additional study is needed to clarify the position of Elisesione in the clade Hesionini.
description: Published as part of Jimi, Naoto, Eibye-Jacobsen, Danny & Salazar-Vallejo, Sergio I., 2018, Description of Elisesione imajimai sp. nov. From Japan (Annelida: Hesionidae) and A Redescription of E. problematica (Wesenberg-Lund, 1950) and Its Confirmation Within Hesionini, pp. 1-9 in Zoological Studies 57 (8) on pages 6-8, DOI: 10.6620/ZS.2018.57-08, http://zenodo.org/record/8055762