New species of the genus Spio (Annelida, Spionidae) from the southern and western coasts of Korea Author Lee, Geon Hyeok Department of Biological Sciences, Inha University, Incheon 22212, Republic of Korea Author Meissner, Karin German Centre for Marine Biodiversity Research, Senckenberg am Meer, c / o Universitaet Hamburg, Martin-Luther-King-Platz 3, D- 20146, Hamburg, Germany Author Yoon, Seong Myeong Department of Biology, College of Natural Sciences, Chosun University, Gwangju 61452, Republic of Korea smyun@chosun.ac.kr Author Min, Gi-Sik Department of Biological Sciences, Inha University, Incheon 22212, Republic of Korea mingisik@inha.ac.kr text ZooKeys 2021 2021-11-15 1070 151 164 http://dx.doi.org/10.3897/zookeys.1070.73847 journal article http://dx.doi.org/10.3897/zookeys.1070.73847 1313-2970-1070-151 73661A23F5634D589A81E55AB3CFCF45 C48A6D44BB505B069CC80C986FD30EA2 Spio pigmentata sp. nov. Spio filicornis : Paik, 1975: 420, 1982: 808, 1989: 465, fig. 175. Spio sp. 2: Abe and Sato-Okoshi, 2021: 63, fig. 9L-N. Material examined. Type locality . Yellow Sea , Korea , 36°15'42.9"N , 126°32'47.9"E , intertidal sand. Holotype . Complete , without palps, formalin (NIBRIV0000888168) (Fig. 2 ), 21 Oct. 2020 . Paratypes . Four complete (NIBRIV0000888164-7), three complete ( SMF 30259 ), two complete (ZMH P-30424), formalin, Yellow Sea, Korea , 37°26'50.0"N 126°22'3.9"E , 13 Jan. 2021 , intertidal sand . Figure 2. Spio pigmentata sp. nov., holotype , palps removed, fixed in formalin, NIBRIV0000888168. Non-type materials . Yellow Sea , Korea , intertidal sand: 27 anterior fragments (af), formalin, 34°18'43"N , 126°1'59"E , 22 Aug. 2017 ; 1 complete (NIBRIV0000862794), 33 af, formalin, 34°41'22.5"N , 125°25'43.8"E , 16 May. 2018 ; 71 af, formalin, 35°40'45.2"N , 126°31'26.5"E , 18 Mar. 2018 ; 14 af, 95% ethanol, 35°38'03.4"N , 126°27'57.2"E , 17 May. 2018 ; 5 af, 95% ethanol, 35°39'16.4"N , 126°29'26.0"E , 19 Sep. 2020 ; 4 af, 95% ethanol, 35°35'44.6"N , 126°29'07.9"E , 18 Sep. 2020 , 5 complete, formalin, 4 af (NIBRIV0000888159-60), 95% ethanol, 35°35'44.6"N , 126°29'07.9"E , 19 Sep. 2020 ; 1 af, formalin, 35°40'44.2"N , 126°31'29.7"E , 21 Sep. 2020 ; 1 af, formalin, same locality as holotype, 21Oct. 2020 ; 9 complete, 1 af, formalin, same locality as paratypes , 15 Jan 2021 . Korea Strait , Korea : 10 af, formalin, 34°28'05.5"N , 127°28'16"E , 26 May. 2017 , intertidal sand; 3 complete, 22 af, formalin, 34°11'03.7"N , 126°54'37.5"E , 26 Jul. 2017 , intertidal sand; 2 af, 95% ethanol, 34°53'19.9"N , 128°26'41.2"E , 20 Jul 2020 , intertidal muddy sand; 5 af, formalin, 35°40'44.2"N , 126°31'29.7"E , 21 Sep. 2020 , intertidal sand; 1 af, formalin, 2 complete (NIBRIV0000888162-3), 95% ethanol, 34°55'37.7"N , 128°02'13.3"E , 23 Jun. 2020 , muddy sand between gravel and macrophytes; 8 complete, 2 af, formalin, 1 af (NIBRIV0000888161), 95% ethanol, 34°43'45.1"N , 127°57'09.7"E , intertidal sand; 1 af, formalin, 36°13'53.3"N , 126°31'47.2"E , 20 Oct. 2020 , intertidal sand; 1 af, formalin, 36°09'41.2"N , 126°31'11.1"E , 20 Oct. 2020 , intertidal sand . Diagnosis. Prostomium broadly rounded, slightly expanded at anterolateral margin, extending to chaetiger 1; nuchal organs with short median and long lateral ciliary bands, lateral bands extending up to transverse ciliated band (tcb) of chaetiger 3. Metameric dorsal ciliated organs double-paired, present from chaetiger 3. Branchiae from chaetiger 1 to almost end of body, length of first pair slightly shorter than that of second pair; branchiae mostly free from notopodial lamellae. White dots present from about chaetiger 3 to the end of the middle body region; three pairs of white dots per chaetiger. Neuropodial hooded hooks tridentate, present from chaetiger 11, uppermost tooth very inconspicuous. Pygidium with thin dorsolateral pair and stout but slightly longer ventral pair of anal cirri. Description. Holotype complete specimen with 67 chaetigers, about 15.7 mm in length and about 1.0 mm in width (Fig. 2 ). Other specimens complete with 58-73 chaetigers, 12.0-17.0 mm in length and 0.9-1.2 mm in width. Prostomium entire and rounded anteriorly, slightly expanded at anterolateral margin, extending to chaetiger 1; prostomium with orange-brown pigmentation on anterior part, middle part of prostomium comparatively broad, posterior part with highly elevated papilla; two pairs of black eyes arranged in trapezoid; anterior pair larger, slightly crescent-shaped or oval, widely spaced; posterior pair smaller, rounded, closely spaced; weak transverse depression between anterior and middle part of prostomium (Figs 3A, B , 6A , 7A ). Peristomium separated from prostomium by a narrow furrow (Fig. 7A ). Peristomial palps reaching chaetigers 6-9 (Fig. 5A ). Figure 3. Spio pigmentata sp. nov. A-C holotype (NIBRIV0000888168) D-F paratype (NIBRIV0000888166) A anterior end, dorsal view B anterior end, lateral view C posterior end, dorsal view D ventral sabre chaeta from chaetiger 52 E anterior neurochaetae from chaetiger 22 F neuropodial hooded hook from chaetiger 22. Scale bars: A-C = 0.5 mm, D-F = 20.0 μm . Nuchal organs and metameric dorsal ciliated organs distinctly observed in well-preserved and live specimens; nuchal organs U-shaped due to posterior fusion of median and lateral ciliated bands, long and recurved on chaetiger 2, and reaching to first transverse ciliated band (tcb) on chaetiger 2 (Figs 3A , 6A , 7A ). Metameric dorsal ciliated organs double paired, present from between branchiae 3 and 4 (i.e., after second tcb), extending up to chaetiger 40 in holotype (38-47 in 62-73 chaetiger individuals) (Figs 3A , 5 , 6A , 7A ). White dots present from chaetiger 3 to chaetiger 50 in holotype (42-52 in 62-73 chaetiger individuals); three pairs of white dots per chaetiger; lateral two pairs closely spaced (Figs 5B , 6B, C , 7B ). Intersegmental transverse ciliation absent. Branchiae present from chaetiger 1 to almost end of body, absent only on last 2 or 3 (rarely 4) chaetigers (Fig. 2 ); length of first pair of branchiae two-thirds to four-fifths the length of second pair (Fig. 3A, B ); comparatively longest and widest branchiae on chaetigers 2-12, becoming thinner and shorter posteriorly; about last 10 branchiae distinctly shorter and thinner; branchiae with cilia on inner and furrow on outer side; branchiae mostly separated from postchaetal notopodial lamellae (Fig. 4 ). Notopodia on chaetiger 1 slightly shifted dorsally; notopodial postchaetal lamellae almost lanceolate (Fig. 4A ); from chaetiger 2 lamellae broadly rounded, slightly tapered superiorly (Fig. 4B-D ), becoming smaller in middle to posterior chaetigers (Fig. 4F ), and larger, subtriangular in about last 17 chaetigers (Fig. 4G ). Neuropodial postchaetal lamellae rounded in about first four chaetigers, becoming broader and larger in along anterior and middle chaetigers, largest in posteriormost chaetigers (Fig. 4 ). Figure 4. Spio pigmentata sp. nov., paratype (NIBRIV0000888166) A-G parapodium from chaetiger 1, 10, 21, 22nd last, 11th last, and 7th last, all anterior view. Scale bars: 0.2 mm. Notopodial chaetae all capillaries; notochaetae in anterior and middle chaetigers arranged in two rows; notochaetae of anterior row with stout sheath, heavily granulated, slightly shorter than chaetae of posterior row, granulation disappearing in middle chaetigers; notochaetae of posterior row thinner, with narrow sheath, non-granulated; additional fascicle of 6-9 very long, thin capillaries without granulations present at superior position, longest in first three chaetigers; notochaetae in posterior chaetigers thin and long, arranged in irregular rows. Neuropodial chaetae with granulated or non-granulated capillaries, hooded hooks, and inferior fascicle of capillaries; capillaries of anterior neuropodia arranged in two rows; neurochaetae of anterior row with distinct sheaths, stout, heavily granulated (Fig. 3E ); neurochaetae of posterior row non-granulated, less stout, replaced by 7-9 hooded hooks from chaetiger 11 (rarely 12); neuropodial hooded hooks tridentate, main fang well developed, uppermost tooth inconspicuous (Fig. 3F ); inferior fascicle of 2-5 long, thin, non-granulated capillaries from chaetiger 1, replaced by 2-4 (usually 3) stout granulated, ventral sabre chaetae in inferiormost position from about chaetigers 16-19 (rarely 13-15) (Fig. 3D ). Pygidium with two pairs of anal cirri; dorsolateral pair shorter and thinner, comparatively widely spaced, and ventral pair longer, very stout, conical with rounded tip and closely spaced (Fig. 3C ). Pigmentation. Highly variable but conspicuous in live or well-preserved specimens (some specimens without pigmentation). Palps in live specimens with variable pigmentation, about 6-15 light to dark brown spots or black ringed appearance (Fig. 5A, B ); pigmentation fades in formalin- and ethanol-fixed specimens, but light brown pigmentation along the food groove remains. Well-preserved specimens with orange-brown and black pigmentation as follows: medial part of prostomium with orange-brown pigmentation, often faded in formalin- and ethanol-fixed specimens; prostomium with black pigmentation on the anterior to transverse depression margin of the prostomium, dorsal side of the peristomium next to the prostomium; black pigmented patches in front of, and in particular, behind tcb dorsolaterally in about the first six chaetigers in holotype (Fig. 6A ), and some specimens with distinct patches (Fig. 5B ). If black pigmented patches are distinct on the ventral side, white dots (pores of ventral glands) are clearly visible (Figs 5D , 6B ). Figure 5. Spio pigmentata sp. nov., live specimens in seawater A specimens with palps, black-ringed (left) and dark brown (right), dorsal view B middle body, double-paired dorsal ciliated organs (left) and ventral white dots (right) views. Scale bars: 0.5 mm. Methyl green staining pattern (MGSP). The anterior part of the prostomium and peristomium, margins of branchiae and postchaetal lamellae, and anal cirri were intensively stained. Transfer of stained specimens to distilled water for approximately 10 min, resulted in white dots being visible against the bluish background on the ventral side (Fig. 6C ). Three pairs of dots were visible on chaetiger 3 to end of middle body region; lateral two pairs closely spaced, easily confused as one pair. Figure 6. Spio pigmentata sp. nov. A, B holotype (NIBRIV0000888168), fixed in formalin C, D paratype (NIBRIV0000888167), fixed in formalin A anterior end, dorsal view B anterior end, ventral view C methyl green staining pattern of anterior end, ventral view, white dots (arrows) D neuropodial hooded hooks from chaetiger 15, inconspicuous uppermost tooth (arrow). Scale bars: 0.5 mm (A-C) ; 20.0 μm D . Biology. In the present study, the specimens were found mostly in intertidal zones of fine sand, rarely muddy sand, and sometimes a mixture of gravel and macrophytes ( Zostera marina ). According to Abe and Sato-Okoshi (2021) , planktonic larvae of Spio sp. 2 with two rows of black melanophore spots on each side of the dorsum from chaetiger 1 onward, linked by band-shaped medial black pigmentation from chaetiger 4 or 5 are found in Sasuhama and Onagawa Bay between April and August (see cited publication for further details). Adult specimens were collected from muddy sand sediments of shallow waters in Sasuhama, Japan ( Abe and Sato-Okoshi 2021 ). Etymology. The specific name, Spio pigmentata , originates from the Latin word pigmentum, meaning "pigment" This name refers to the new species having conspicuous black pigmentation on the body. Distribution. Along the southern and western coasts of Korea; Sasuhama and Onagawa Bay, north-eastern Japan. Figure 7. Spio pigmentata sp. nov., paratype (NIBRIV0000888165). A anterior end, dorsal view, palps removed B right half of middle chaetiger, ventral surface, gland openings (arrows). wScale bars: 0.2 mm A ; 40.0 μm B .