''Hermadionella'' is a genus of marine

polychaete Polychaeta () is a paraphyletic class of generally marine Annelid, annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called c ...

worms belonging to the family

Polynoidae Polynoidae is a family (biology), family of marine Polychaete worms known as "scale worms" due to the scale-like elytron (Annelida), elytra on the dorsal surface. Almost 900 species are currently recognised belonging to 9 subfamilies and 167 gen ...

, the scaleworms. ''Hermadionella'' contains 3 species which are known from the north-west

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

and

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...

s from the

intertidal The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various sp ...

to depths of about 200 m.Bock G, Fiege D, Barnich R (2010) Revision of Hermadion Kinberg, 1856, with a redescription of Hermadion magalhaensi Kinberg, 1856, Adyte hyalina (G.O. Sars, 1873) n. comb. and Neopolynoe acanellae (Verrill, 1881) n. comb. (Polychaeta: Polynoidae). Zootaxa 2554: 45–61. https://doi.org/10.11646/zootaxa.2554.1.4.

Description

''Hermadionella'' are long-bodied scale worms with 50–60 or more segments and 15 pairs of

elytra An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometime ...

; the posterior-most 15–20 or more segments are thus not covered by elytra. The

prostomium The prostomium (From Ancient Greek, meaning "before the mouth"; : prostomia; sometimes also called the "acron") is the Cephalization, cephalized first body segment in an annelid worm's body at the anterior end. It is in front of (but does not in ...

is bilobed and rounded anteriorly, lacking acute cephalic peaks. The lateral antennae are inserted ventrally, beneath median antenna and the antennal styles are covered with slender papillae. The neuropodial lobe is elongate, tapering to a slightly rounded tip. The

notochaetae A chaeta or cheta (; ) is a chitinous bristle or seta found on annelid worms, although the term is also frequently used to describe similar structures in other invertebrates such as arthropods. Polychaete annelids (''polychaeta'' literally mean ...

have truncate tips and are distinctly thicker than the

neurochaetae A chaeta or cheta (; ) is a chitinous bristle or seta found on annelid worms, although the term is also frequently used to describe similar structures in other invertebrates such as arthropods. Polychaete annelids (''polychaeta'' literally mean ...

. Neurochaetae with simple or bidentate tips may both be present. ''Hermadionella'' is distinguished from the similar genus '' Hermadion'' by having a longer body (''Hermadion'' have fewer than 50 segments) and notochaetae with truncate tips, which are absent in ''Hermadion''.Uschakov, Pavel Vladimirovich. 1982. olychaetes of the Suborder Aphroditiformia of the Arctic Ocean and the Northwestern Part of the Pacific, Families Aphroditidae and Polynoidae 1-272. FAUNA SSSR, Mnogoshchetinkovyye chervi (Fauna of the USSR, Polychaeta). Moscow., available online at http://www.annelida.net/translation/transl.html

Species

As of October 2020, ''Hermadionella'' contains three species: * '' Hermadionella chayvoensis'' Alalykina, 2011 * '' Hermadionella nipponicus'' (Imajima & Hartman, 1964) * '' Hermadionella truncata'' (Moore, 1902)

References

{{Taxonbar, from=Q20639421 Phyllodocida Polychaete genera