taxonID	type	description	language	source
364787F1FFF66B593BC789BDFC149CB7.taxon	type_taxon	Type species. Euchonoides moeone n. sp., herein designated, by monotypy.	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF66B593BC789BDFC149CB7.taxon	diagnosis	Diagnosis. Body short with a reduced number of abdominal chaetigers (8 – 10). Three pairs of radioles. Radiolar skeleton present in branchial lobes, radioles and pinnules. Each radiolar skeleton with two longitudinal rows of cells from radiole base to third proximal pair of pinnules, remainder of each radiole and all pinnular skeletons with single rows of cells. Pinnules unpaired, alternating (snowflake arrangement). Basal membrane absent; radiolar flanges absent; radiolar eyes absent. Dorsal lips without radiolar appendage. Ventral lips absent. Dorsal pinnular appendages absent. Ventral pinnular appendages present. Parallel lamellae absent. Ventral sacs absent. Radiolar lobes fused along dorsal midline; without dorsal or ventral basal flanges. Anterior peristomial ring distinctive, but no visible annulation between anterior and posterior peristomial ring. Peristomial eyes present. Peristomial vascular loops absent. Posterior peristomial ring collar incised ventrally; separated dorsally by distinct gap. Collar chaetae fascicles protruding from a short lobe, narrowly hooded chaetae. Glandular ridge on thoracic chaetiger 2 present. Superior thoracic notochaetae elongate, narrowly hooded. Inferior thoracic notochaetae includes bayonet and broadly hooded chaetae. Thoracic neuropodial uncini acicular, handles long, hoods absent, a large tooth above the main fang followed by a series of small ones. Companion chaetae absent. Thoracic chaetiger 3 always enlarged (2 – 3 times longer than wide). Ventral thoracic shields not differentiated. Neuropodial abdominal fascicles with elongate, narrowly hooded chaetae. Anterior abdominal uncini with square breasts, handle absent, and rasp-shaped dentition. Belt (clitellum-like) on third abdominal chaetiger present. Pre-pygidial depression composed by three chaetigers, with lateral wings. Uncini from pre-pygidial depression similar to those from anterior abdomen. Pygidium without anal cirrus. Pygidial eyes absent.	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF66B593BC789BDFC149CB7.taxon	etymology	Etymology. The genus name is a free combination of Euchone and the Latin sufix - oides, in relation to the similarities between the new genus with the genus Euchone. Gender. Neuter. rina bicincta (Ozolinsh, 1988). & Rouse, 2007).	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF66B593BC789BDFC149CB7.taxon	discussion	Remarks. The new genus is proposed based on a combination of distinctive characters (see Table 2) but especially by the presence of an oblique, broad belt on the third abdominal chaetiger (Figs 1 A – B; 3 A) instead of the typical glandular ridges. This abdominal structure is not morphologically similar to the usual, glandular ridge on thoracic chaetiger 2 or to the glandular abdominal ridges in other Chone, “ Chiade ” or Dialychone species (Tovar-Hernández 2008). These typical glandular ridges are whitish and occupies only the external half of the epithelium; these are composed of strongly differentiated acidophil glandular cells, tubular-shaped with granulose secretions such as described by Tovar-Hernández & Sosa-Rodríguez (2006). The abdominal belt of E. moeone n. sp. is conspicuous (visible without staining), but histological sections show that it is not a differentiated epithe- lium from the rest, it is only a thicker epithelium as the clitellum of clitellates, with markedly basophil glands. Reproductive features associated to the abdominal segment 3 such as presence of modified chaetae, genital pores or markings were not found, but germ cells and oocytes in different phases of development were found in abdominal chaetigers 1 – 3. A similar abdominal belt was reported for Amphicorina bicincta (Ozolinsh, 1988) and on another undescribed Amphicorina species from Chukchi Sea (Leslie Harris pers. com.). These three species are similar and the differences are presented on remarks for the new species and on Table 1. In her review of Oriopsis, Giangrande et al. (1999: 196) emphasized that A. bicincta probably belonged to a new genus. In addition to the belt on abdominal chaetiger 3; the pinnular arrangement (snowflake); the presence of three pairs of radioles and a pre-pygidial depression composed of three chaetigers, the new genus is established based also on a combination of unique features as supported above. Among these unique set of characters, the radiolar skeleton of Euchonoides n. gen. is similar to that present in Terebrasabella Fitzhugh & Rouse, 1999: each radiolar skeleton has two rows of cells from radiole base to third proximal pair of pinnules, and the remainder of each radiole with single rows of cells. The genera Terebrasabella, Caobangia Giard, 1893 and Amphiglena Claparède, 1864 also lack ventral lips. A low number of radioles have been reported in few sabellids. Terebrasabella has only two pairs of radioles whereas the presence of three pairs of radioles have been reported in Desdemona ornata Banse, 1957, some species of Amphicorina Claparède, 1864, Euchone incolor, E. scotiarum, E. trilobata, E. hanckocki and Euchone x sensu Cochrane and the new genus here described. The new genus is quite remarkable in having such a small number of abdominal chaetigers (8 – 10 chaetigers). In comparison, Terebrasabella present only three abdominal chaetigers, Amphiglena lindae Rouse & Gambi, 1997 has 26 abdominal chaetigers and Caobangia presents 25 – 40 abdominal chaetigers. Enlargement of some chaetigers (not depending of contraction) has been observed in Terebrasabella where posterior abdominal segments are notoriously longer than wide. In the new genus, thoracic chaetiger 3 is also markedly longer than remainder of body segments. Comparing with other sabellid genera having a pre-pygidial depression with lateral wings, radioles are free in Euchonoides n. gen., not joined by a basal membrane and lacks flanges (both, membrane and flanges present in Euchone restricted and Euchoneira). Arrangement of pinnules as snowflake (unpaired, alternating pinnules) is present in Euchonoides n. gen. (feather duster = paired pinnules in Euchone restricted and Euchoneira). Dorsal lips are digitiform without mid-rib support in Euchonoides n. gen. whereas lips are distally tapered with mid-rib in Euchone and broadly rounded without mid-rib in Euchoneira. In Euchonoides n. gen., the third thoracic chaetiger is always enlarged (versus not enlarged in Euchone and Euchoneira). Ventral shields are well differentiated, swollen in Euchone and Euchoneira, but not differentiated in Euchonoides n. gen. Dentition of thoracic uncini of Euchonoides n. gen. is characterized by uncini with a large tooth above the main fang in contrast to the small teeth of Euchone and Euchoneira. The number of abdominal uncini is reduced in Euchonoides n. gen. (8 – 10) but larger in Euchone (up to 29) and Euchoneira (30). See Table 2 for additional comparisons.	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF16B553BC78CD5FD399E1B.taxon	description	(Figs 1 – 6)	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF16B553BC78CD5FD399E1B.taxon	materials_examined	Material examined. Holotype: Mamala Bay, Oahu, Hawaii, Sta. HB 3 R 2, 21 ° 17 ’ 02.8 ’’ N, 158 ° 01 ’ 39.5 ’’ W, Jan / 2016, 70 m, sediment composed primarily of fine and medium grain sand (BPBM R- 3914). Paratypes: same locality, station and date as holotype (20, BPBM R- 3915; 10, UFBA 1582).	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF16B553BC78CD5FD399E1B.taxon	description	Description Body short, rounded in cross section (Fig. 1 A – B). Holotype total thorax-abdomen length 1.67 mm (radiolar crown 0.48 mm), maximum width 0.1 mm. Paratypes ranging from 1.8 – 2.1 mm long (radiolar crown 0.3 – 0.45), maximum width 0.1 mm. Three pairs of radioles (Figs 1 D; 2 D), each with 6 – 12 pinnules, with snowflake (unpaired, alternating pinnules) distribution; radiolar rachis slightly thicker than pinnules (Fig. 1 D). Basal pinnules short, then increasing abruptly in size towards last third of radiolar length, most of pinnules terminate at approximately same height distally (Figs 1 A – B, D; 2 D). Radiolar tips filiform, as long as one quarter of radiolar length (Fig. 2 D). Dorsal lips digitiform, as long as ¼ of the radiolar crown length, without mid-rib (radiolar appendage) (Figs 1 D; 2 D). Ventral lips absent. A pair of ventral radiolar appendages as long as radiolar length (shorter in some paratypes) (Figs 1 D; 2 D). Inter-radiolar membrane and radiolar lateral flanges absent (Fig. 3 B – C). Each radiolar skeleton with two longitudinal rows of cells, in cross section, from radiole base to third proximal pair of pinnules, remainder of each radiole with single rows of cells (Fig. 5 B – C). Radiolar eyes absent. Anterior peristomial ring exposed partially on lateral sides (Fig. 3 B, D), fully exposed dorsally (Fig. 3 C). A pair of brown peristomial eyes (Figs 1 A – B; 2 C). Posterior peristomial ring collar well-developed with entire smooth margins (Figs 1 A – C; 3 C – D). Ventral margin of collar longer than dorsal, with deep mid-incision forming rounded ventral lappets (Figs 1 B – C; 3 D). Lateral collar margins diagonal (oblique) (Figs 1 A; 3 B, D). Dorsal collar margins fused to faecal groove, forming a narrow gap (Fig. 3 C). Collar chaetiger with 4 – 6 elongate, narrowly hooded chaetae of equal length (Fig. 3 C). Ventral shield of collar rectangular (Fig. 2 A), with a transverse patch of cilia (Figs 1 C; 3 D). Thorax composed of seven chaetigers in holotype (paratypes with 3 – 7 chaetigers). Glandular ridge homogeneously narrow on chaetiger 2 (Figs 1 C), light brown in color, when fixed. Thoracic segments increasing in length from chaetigers 1 – 3, chaetiger 3 always longest, 2 – 3 times longer than wide (Figs 1 A, B; 3 A). Ventral glandular shields not differentiated (Figs 1 A – B; 3 A). Notopodia: superior group of chaetae with a row of two elongate, narrowly hooded chaetae; inferior group with one row of two bayonet chaetae (Figs 1 E; 4 A), and one row of broadly hooded chaetae (Figs 1 F; 4 B). Neuropodia: acicular uncini numbering 3 – 4 per torus, handles longer than 5 times the length of crest, hoods absent (Fig. 1 G), a large tooth above the main fang (Fig. 4 C), followed by a series of small ones, dentition covers half of the main fang length (Fig. 4 C). Abdomen with nine chaetigers in holotype, posterior three forming pre-pygidial depression (8 – 10 chaetigers in paratypes, all paratypes with pre-pygidial depression composed of three segments). Third abdominal chaetiger (A 3) with unusual, broad belt (clitellum-like), readily distinct and present in all specimens (Figs 1 A – B; 3 A); dorsally entire, ventrally interrupted by faecal groove; composed of wide glandular, columnar epithelium (Fig. 5 A, E – H, J). Neuropodia with 3 – 6 elongated, narrowly hooded chaetae, slightly longer on posterior-end chaetigers. Anterior abdominal notopodia with 4 – 6 uncini per torus with square breasts, handle absent, and at least nine rows of small, equal sized teeth covering most than 3 / 4 of main fang length (rasp-shaped dentition) (Figs 1 H; 4 D). Pre-pygidial depression with raised membranous lateral flanges (Figs 1 B, J; 3 E; 6 D); tori shorter than anterior abdominal segments, and with decreasing number of uncini (4, 3, 2, respectively); uncini not distinct in shape than rest of anterior abdominal uncini (Fig. 1 I). Pygidium enlarged, bluntly rounded, lacking pygidial eyespots and pygidial cirrus (Figs 1 J, K; 3 E; 5 D). Body color and methyl green staining pattern: Preserved specimens lacking pigmentation. Ventral shields only distinct with staining (Fig. 2 A – B). Methyl green stained more intensely transverse glandular bands of thorax and anterior abdomen (Fig. 2 A – B); posterior abdomen staining lightly, pygidium staining more distinctly than pre- pygidial depression (Fig. 2 B); thoracic ventral region staining more intensely than respective dorsal region, especially ventral shields (Fig. 2 A – B). Tubes: Tube composed of fine and medium grain sand particles and shell fragments bound by mucus membrane and fine layer of silt. Reproduction: Several individuals with developing radiolar crowns and variable number of thoracic segments (3 – 7) were found within tubes of adults, indicating intratubular direct larval development. In these offspring, radioles are rudimentary (as small, rounded protuberances or short, digitiform radioles without pinnules) and thorax is not completely formed (few chaetigers are present and the first three thoracic segments are narrower and shorter than rest of the body). Ripe males or hermaphrodites were not found in the hundreds of examined specimens, but packages of germ cells were observed in abdominal segments A 1 – A 3 (Fig. 5 A, G). Oogenesis was observed only in abdominal segments A 1 – A 3. Oocytes measured 37 – 50 μm in diameter, and few oocytes (three per specimen) were found in abdominal segments A 1 – A 3 (Fig. 5 G, I).	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF16B553BC78CD5FD399E1B.taxon	discussion	Remarks. Cochrane (2003) recognized a group of small-sized Euchone species with snowflake pinnular arrangement and the presence of three chaetigers in the pre-pygidial depression named by her as ‘ Chiade’. This clade is composed of E. trilobata (Banse, 1957) from the Falkland Islands, E. incolor Hartman, 1965 from off New England, E. hancocki Banse, 1970 from southern California, E. scotiarum Hartman, 1978 from Antarctica, and Euchone x sensu Cochrane, 2000 from the North Sea and the Norwegian Sea. These species of ‘ Chiade’ differ in the number of abdominal segments anterior to pre-pygidial depression and on the presence of glandular ridges similar to that in thoracic chaetiger 2, but also present in some abdominal chaetigers. Abdominal glandular ridges are present in E. incolor (pre-chaetal on third abdominal chaetiger), E. hancocki (post-chaetal on first abdominal chaetiger) and Euchone x (pre-chaetal on third abdominal chaetiger). Euchone trilobata do not have abdominal glandular ridges and these were not described or corroborated in E. scotiarium (Banse 1957). However, specimens from Hawaii here studied are unique among all the species of ‘ Chiade’ by the presence of an oblique, broad belt on third abdominal chaetiger. A similar abdominal belt was reported for Amphicorina bicincta (Ozolinsh, 1988) and an undescribed species of Amphicorina from Chukchi Sea (Leslie Harris pers. com.). In their review of Oriopsis, Giangrande et al. (1999: 196) emphasized that A. bicincta probably belongs to a new genus. Amphicorina bicincta and E. moeone n. sp. are similar in relation to the presence and shape of the oblique abdominal belt on third abdominal chaetiger and presence of three pairs of radioles but these are readily distinguished by the presence of a broad glandular ridge on thoracic chaetiger 2 in A. bicincta (narrow in E. moeone n. sp.) (see Table 1 for a detailed comparison). Terebrasabella heterouncinata Fitzhugh & Rouse, 1999 has one pair of densely ciliated sperm ducts present along the posterior margin of thoracic chaetiger 8. These ducts are located ventro-laterally, just posterior to neuropodial uncini, extending dorsally and sometimes slightly anteriorly as low ridges; these ducts terminate at the lateral margins of faecal grove (Fitzhugh & Rouse 1999). Reviewing SEM images by Fitzhugh & Rouse (1999: fig. 5), there is a great external similarity between sperm ducts of Terebrasabella and the belt of the new genus located on abdominal segment 3. Both are low ridges and terminate on lateral margins of the faecal groove. To date, spermatozoa have not been observed in the new Hawaiian genus.	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF16B553BC78CD5FD399E1B.taxon	etymology	Etymology. The new species epithet derives from the Hawaiian language and the implied meaning of moeone in Hawaiian is ‘ small worm that hides in the sand’.	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
364787F1FFF16B553BC78CD5FD399E1B.taxon	distribution	Distribution. The type locality is Mamala Bay, Oahu, Hawaii at the vicinity of Barbers Point sewage outfall at 70 m. This species has also been collected at Ala Wai Canal, Kailua Bay, and Waianae on Oahu from shallow subtidal to up to 100 m in fine and medium sand.	en	Magalhães, Wagner F., Bailey-Brock, Julie H., Tovar-Hernández, María Ana (2020): An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii. Zootaxa 4763 (1): 85-98, DOI: 10.11646/zootaxa.4763.1.7
