Unearthing the diversity of Japanese Magelona (Annelida: Magelonidae); three species new to science, and a redescription of Magelona japonica Author Taylor, Abbie Department of Natural Sciences, Amgueddfa Cymru - Museum Wales, Cathays Park, Cardiff CF 10 3 NP, Wales, U. K. & School of Biosciences, Cardiff University, Cardiff CF 10 3 AX, Wales, U. K. Author Mortimer, Kate 0000-0002-3430-1659 Department of Natural Sciences, Amgueddfa Cymru - Museum Wales, Cathays Park, Cardiff CF 10 3 NP, Wales, U. K. & Katie. Mortimer @ museumwales. ac. uk; https: // orcid. org / 0000 - 0002 - 3430 - 1659 ortimer@museumwales.ac.uk Author Jimi, Naoto Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Toba, Japan & Centre for Marine & Coastal Studies, Universiti Sains Malaysia 11800 USM, Penang, Malaysia text Zootaxa 2022 2022-10-21 5196 4 451 491 journal article 171433 10.11646/zootaxa.5196.4.1 5981d91b-b1c3-4599-b241-58cd7f3937b6 1175-5326 7235610 D11B689F-70DF-4B27-959D-63A520D125E2

TABLE 2. Morphological characters of five observed Japanese magelonid species (Magelona agoensis is in need of redescription, type material lost and no fresh material available, thus not included).

Species/Character	M. alba sp. nov.	M. armatis sp. nov.	M. boninensis sp. nov.	M. cf. cornuta	M. japonica
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Size/Dimensions	Slender	Stout, armoured appearance	Moderate	Moderate	Stout
Prostomium
L:W ratio	L>W	L<W	L>W	L<W	L<W
Horns	Rudimentary	Rudimentary	Distinct	Distinct	Distinct
Shape	Rounded	Rounded triangular	Spatulate	Rounded	Triangular
Anterior margin	Triangular	Straight, squared	Triangular, minutely crenulated (high magnification)	Small crenulations	Triangular
Pairs of ridges	Two	Two	Two	Two	Two
Prostomial markings	Oblong	Distinct, arched lines	Oblong and small circular	Oblong	Light to none
Thorax
No. of chaetigers	Nine	Nine	Nine	Nine	Nine
Pigment band	None	None	None	None	Distinct, dark red, 5–9
Notopodial lamellae 1–7	Slender triangular, postchaetal to subchaetal	Foliaceous	Spatulate to foliaceous, upper margins slightly crenulated	Large, foliaceous	Slender triangular
Neuropodial lamellae 1–7	Slender triangular, ventral becoming prechaetal	Large, spatulate with postchaetal expansion, prechaetal on 1, ventral 2–7	Triangular, ventral, Slight postchaetal expansion from ~5	Slender, cirriform, ventral with slight postchaetal expansion	Scoop-shaped 1–4, digitiform from 5, ventral 1–6, postchaetal from 7
Superior Dorsal Lobes (SDL)	Chaetigers 1–8	Chaetigers 1–9	Chaetigers 1–8	Chaetigers 1–8	Absent
Ventral swellings	Chaetigers 6–8, paired, reniform	Distinct, oval	Chaetigers 6–9, paired, reniform	Chaetigers 6–8, very light, paired, reniform	Absent
Chaetiger Eight
Notopodial lamellae	Slender triangular, subchaetal	Foliaceous	Foliaceous, upper margins slightly crenulated	Large, foliaceous	Slender triangular
Neuropodial lamellae	Digitiform, prechaetal, slight postchaetal expansion	Digitiform ventral, triangular postchaetal	Digitiform prechaetal, triangular postchaetal	Short, cirriform prechaetal, triangular postchaetal	Slender triangular, postchaetal
Chaetae 1–8	Smooth, unilimbate	Smooth, unilimbate	Smooth, bilimbate	Smooth, unilimbate	Smooth, unilimbate
Chaetiger Nine
Notopodial lamellae	Low, triangular	Triangular	Rounded postchaetal, expanded as cirriform processes	Triangular, rounded tips	Triangular
Neuropodial lamellae	Digitiform prechaetal, slender triangular postchaetal	Broad, triangular, postchaetal, small triangular prechaetal	Digitiform prechaetal, triangular postchaetal	Cirriform, prechaetal, triangular postchaetal	Triangular, postchaetal
Chaetae	Unilimbate, slightly pennoned	Unilimbate, slightly thicker	Slightly irregular blades, bilimbate, tips slightly bent	Smooth, unilimbate	Smooth, unilimbate
Abdomen
Lamellae	Foliaceous, basally	Large, rounded to	Rounded triangular	Large, rounded	Triangular,
	constricted	oblong, basally	to spatulate, basally	spatulate, distally	pointed tips,
		constricted	constricted	pointed, basally	not basally
				constricted	constricted
Postchaetal	None	Small, anterior	Triangular	Triangular	None
expansion		abdomen only
Triangular	Digitiform, fairly	Triangular, sporadic	Triangular, long	Long, triangular	Minute to
Processes (DML,	long				sporadic,
VML)					triangular
Hook orientation	vis-à-vis	vis-à-vis	vis-à-vis	vis-à-vis	vis-à-vis
Hook dentition	Tridentate	Tridentate	Tridentate	Tridentate	Tridentate
Aciculae chaetae	None observed	None observed	Present	Present	None observed
Pouches	None observed*	None observed*	Paired, posteriorly	None observed*	None observed
			open, medially split,
			from ~ 32–50
Pygidium	Unknown	Unknown	Rounded triangular	Unknown	Conical
Anus/anal cirri	Unknown	Unknown	Small, rounded,	Unknown	Small, ventral/
			ventral/long, digitiform		anal cirri
			anal cirri		unknown
Colour	White in alcohol	Cream in alcohol	Cream in alcohol	Cream-white in	Pale-yellow,
				alcohol	reddish-brown
					pigment band
Staining Pattern	Staining absent in	Stain persists around	Speckled in abdomen,	Inconspicuous,	No clear pattern,
(MG)	posterior thorax	mid-thorax	posterior thorax, and	light speckling	some speckling
			papillae
Tube Building	Unknown	Unknown	Unknown	Unknown	Yes
Type/Locality	Hokkaido, Japan	Kanagawa, Japan	Bonin Islands, Japan	N/A	Incheon, Korean
					Archipelago;
					Onagawa,
					Miyagi
					Prefecture
Habitat/Ecology	Currently only	Currently only known	Currently only known	Current record	Soft, muddy
	known from 5 m in	between 3–5 m in	from intertidal sandy	31 m in sandy	and sandy
	sandy sediments	sandy sediments	sediments	sediments	sediments,
					generally <30
					m (Choi & Koh
					1986; Baek et
					al. 2007; Yoo et
					al. 2011)
Distribution	Temperate	Temperate Northern	Temperate Northern	Temperate	Temperate
	Northern Pacific	Pacific	Pacific	Northern Pacific/	Northern Pacific
				Central Indo-	(see remarks)
				Pacific(?)
Species/Character	M. alba sp. nov.	M. armatis sp. nov.	M. boninensis sp. nov.	M. cf. cornuta	M. japonica