Echinoderes regina, Grzelak & Sørensen, 2022

Grzelak, Katarzyna & Sørensen, Martin V., 2022, Echinoderes galadrielae Grzelak & amp; Sørensen 2022, sp. nov., Zoological studies (Zool. Stud.) 55 (32), pp. 32-32 : 3-11

publication ID	https://doi.org/ 10.5281/zenodo.7225407
persistent identifier	https://treatment.plazi.org/id/7E3687A4-FFAA-D24E-FF15-2075FC54FEB8
treatment provided by	Valdenar
scientific name	Echinoderes regina
status	sp. nov.

Treatment

Echinoderes regina View in CoL sp. nov. Yamasaki urn:lsid:zoobank.org:act:0776C0CE-4E5E-458A-A350-3EDC96B979FF [New Japanese name: Jouou togekawa]

Material examined: All specimens collected 25 November 2014 at 10 m depth near Hon Mieu Island, Nha Trang, Vietnam (12°11.60'N, 109°13.96'E). Holotype: adult female (ZIHU-5045), mounted in Fluoromount G ®. Allotype: adult male (ZIHU-5046); mounted in Fluoromount G ®. Paratypes: four adult females and two adult males (ZIHU-5047-5052), mounted in Fluoromount G ®. Additional material: six specimens for SEM (two adult female, two adult males, and two adults gender undetermined), mounted on aluminum stubs.

Etymology: The species name regina is from Latin, meaning ‘queen’, referring to the species’ large trunk length, similar to that of Echinoderes rex Lundbye et al. (2011) ( rex , ‘king’ in Latin).

Diagnosis: Echinoderes with large trunk (451-503 m); with short acicular spine middorsally on segment 4 and sublaterally on segments 6 and 7; short tubules lateroventrally on segment 5 and sublaterally on segment 8; laterodorsal tubules on segment 10; large sieve plates on segment 9; primary pectinate fringe of segments 2-9 with conspicuously wider tips in middorsal to ventrolateral areas and thinner tips in ventromedial area; lateral terminal spines length 15-20% of trunk length.

Description: Adult with head, neck, and eleven trunk segments ( Figs. 2A, B View Fig , 3A View Fig , 4A View Fig ). See table 1 for measurements. Table 2 indicates the positions of cuticular structures (sensory spots, glandular cell outlets, spines, tubules, and sieve plates).

Head consists of retractable mouth cone and introvert ( Figs. 4 View Fig A-E, 5). Mouth cone with inner oral styles and nine outer oral styles. Exact number and arrangement of inner oral styles not examined. Each outer oral style consists of rectangular basal part and triangular distal part ( Fig. 4C View Fig ). Basal parts of outer oral styles alternating in size: five large in odd sectors of the introvert, and four small in even sectors ( Figs. 4B, C View Fig , 5 View Fig ). Three rows of filose structures present on posterior to basal parts of outer oral styles ( Fig. 4C View Fig ). Anteriormost row consists of three to five longer spinose processes for each outer oral style. Middle row consists of multiple, much shorter and thinner processes, seamlessly covering mouth cone. Posteriormost row consists of one to five cracked-tip spinose processes for each outer oral style. Introvert composed of seven rings of spinoscalids and one ring of trichoscalids ( Figs. 4B, D, E View Fig , 5 View Fig ). Ring 01 includes ten primary spinoscalids, each with basal sheath and smooth long end-piece ( Figs. 4D, E View Fig ). Each basal sheath with three overlapping fringes. Proximal fringe extends into three flat projections, like a trident, covering next fringe. Middle fringe with two lateral projections overlapping end-piece. Distal fringe with five threads projecting between two projections of middle fringe. End-piece of primary spinoscalids is longest unit. Rings 02 and 04 with 10 spinoscalids; rings 03 and 05 with 20 spinoscalids. Spinoscalids of rings 02-05 similar in length. Rings 06 and 07 not examined in detail, but ring 06 with at least five, and ring 07 with at least three relatively short spinoscalids ( Fig. 5 View Fig ). Six trichoscalids attached with trichoscalid plate in sectors 2, 4, 5, 7, 8, and 10.

Neck with 16 placids ( Figs. 2A, B View Fig , 3A View Fig , 5 View Fig ). Midventral placid broadest (ca. 18 m wide at base, ca. 12 m wide at tip). Remaining placids similar in size (ca. 11 m in basal width and ca. 5 m in tip width).

Position

MD segment PD SD LD ML SL LV VL VM 1 gco1 ss ss gco1 ss 2 gco1, ss gco2 ss, gco2, ss gco2, ss, gco1 3 gco1 ss ss gco2 gco1 4 ac gco1 gco2 gco2 gco1 5 gco1 ss gco2, tu gco1, ss 6 gco1 ss gco2, ss ac gco1, ss 7 gco1 ss gco2, ss ac gco1, ss 8 gco1 ss gco2 tu gco1, ss 9 gco1 ss, ss ss si ss gco1, ss 10 gco1, gco1 ss tu ss gco1 11 ss ltas (f), ps (m) lts ss (f)

Segment 1 consists of complete cuticular ring. This and following nine segments with thick pachycycli at anterior margin ( Figs. 2 View Fig A-D, 3A). Non-bracteate cuticular hairs densely cover entire segment ( Fig. 6A View Fig ), but perforation sites are not visible in posterior quarter of the segment ( Figs. 2A, B View Fig , 3A, B View Fig ). Rounded subdorsal and laterodorsal sensory spots located close to anterior margin of the segment ( Figs. 2A View Fig , 6A, D View Fig ). Rounded ventrolateral sensory spots located centrally between anterior and posterior segment margins ( Figs. 2B View Fig , 3A View Fig , 6B View Fig ). Type-1 glandular cell outlets situated anteriorly in middorsal and lateroventral positions ( Figs. 2A, B View Fig , 3A View Fig ). Posterior part of segment with primary pectinate fringe, with all fringe tips similar in length and width ( Figs. 2A, B View Fig , 6A, B View Fig ).

Segment 2 with complete cuticular ring, like segment 1 ( Figs. 2A, B View Fig ). Bracteate cuticular hairs densely covering whole area. One dropletshaped sensory spot in middorsal position, two pairs in laterodorsal position, and one pair in ventromedial position ( Figs. 2A, B View Fig , 3A, B View Fig , 6 View Fig A-C, E). All sensory spots central in position. Type-1 glandular cell outlets of segment 2 and following eight segments situated in anterior part of segment in ventromedial position ( Figs. 2B View Fig , 3A, B View Fig ). Type-1 glandular cell outlet situated anteriorly in middorsal position ( Fig. 2A View Fig ). Paired type-2 glandular cell outlets in paradorsal, laterodorsal, and ventromedial positions ( Figs. 2A, B View Fig , 3A, B View Fig , 6 View Fig AC, E). All type-2 glandular cell outlets of segment 2 and following six segments situated centrally on segment. Posterior margin of segment ends as primary pectinate fringe showing tips similar to those of the preceding segment in ventrolateral to middorsal position, and smaller and thinner tips in ventromedial position ( Figs. 2A, B View Fig , 6A, B View Fig ).

Segment 3 and following eight segments consist of one tergal and two sternal plates ( Figs 2A, B View Fig ). This and following seven segments entirely covered with bracteate cuticular hairs except for anterior area. Paired sensory spots in subdorsal and midlateral positions ( Figs. 2A, B View Fig , 3A View Fig ). Type-1 glandular cell outlet situated anteriorly in middorsal position ( Fig. 2A View Fig ). Pair of type-2 glandular cell outlets in lateroventral position ( Figs. 2B View Fig , 3A, B View Fig ). Pectinate fringe on segment 3 and following six segments as on segment 2 ( Figs. 2A, B View Fig ).

Segment 4 with short middorsal acicular spine ( Figs. 2A View Fig , 3C View Fig , 6F View Fig ), and without sensory spots. Pair of type-1 glandular cell outlets on segment 4 and following five segments, situated in anterior part of segment in paradorsal position ( Fig. 2A View Fig ). Type-2 glandular cell outlets in subdorsal and laterodorsal positions ( Figs. 2A, B View Fig , 3A, C View Fig , 6F View Fig , 7A View Fig ).

Segment 5 with lateroventral tubules ( Figs. 2B View Fig , 7B View Fig ). Sensory spots in laterodorsal and ventromedial positions ( Figs. 2A, B View Fig , 3A View Fig , 7A, B View Fig ). Paired type-2 glandular cell outlets anteriorly in lateroventral position ( Fig. 2B View Fig ).

Segment 6 with short sublateral acicular spine ( Figs. 2A, B View Fig , 3D View Fig , 7B, D View Fig ), and subdorsal, midlateral, and ventromedial paired sensory spots ( Figs. 2A, B View Fig , 3A, D View Fig , 7B View Fig ). Paired type-2 glandular cell outlets in midlateral position ( Figs. 2A, B View Fig , 3A, D View Fig , 7B View Fig ).

Segment 7 similar to segment 6 ( Figs. 2A, B View Fig , 3A View Fig , 7B View Fig ).

Segment 8 with sublateral tubules ( Figs. 2A, B View Fig , 3E View Fig , 7C View Fig ). Paired sensory spots in subdorsal and ventromedial positions ( Figs. 2A, B View Fig , 3A View Fig , 7C View Fig ). Paired type-2 glandular cell outlets in laterodorsal position ( Figs. 2A, B View Fig , 3E View Fig ).

Segment 9 with two pairs of subdorsal sensory spots and one pair each of laterodorsal, ventrolateral, and ventromedial sensory spots ( Figs. 2 View Fig A-D, 3A, 7C). Pair of sieve plates with oval-shaped sieve area and single posterior pore situated in midlateral position ( Figs. 2 View Fig A-D, 3A, F).

Segment 10 with laterodorsal tubules ( Figs. 2A, C View Fig , 3G View Fig , 7E, F View Fig ). Laterodorsal tubules in males about twice as long as in females ( Table 1). Paired subdorsal and ventrolateral sensory spots present ( Figs. 2B, D View Fig , 3A View Fig , 7E, F View Fig ). Two type-1 glandular cell outlets present in middorsal position. Posterior margin ends as primary pectinate fringe with short, thin tips.

Segment 11 with lateral terminal spines ( Figs. 2 View Fig A-D, 3A, G, 4A, 7E, F). Short, thin lateral terminal accessory spines present only in females ( Figs. 2A, B View Fig , 3G View Fig , 7E View Fig ), and three pairs of penile spines only in males ( Figs. 2C, D View Fig , 7F View Fig ). Cuticular hairs absent. Paired sensory spots present in subdorsal position ( Figs. 2A, C View Fig , 7E, F View Fig ). Additional paired sensory spots present in ventrolateral position in female. Tergal plate projects laterally and ends in short, pointed tergal extensions ( Figs. 2A, C View Fig , 3G View Fig , 7E, F View Fig ).

Remarks: The combination of the arrangement of spines and tubules and the presence of large sieve plates assigns Echinoderes regina sp. nov to be a member of the Echinoderes coulligroup (see also DISCUSSION). Within the group, E. regina sp. nov. is most similar to Echinoderes annae SØrensen et al. (2016), Echinoderes maxwelli [ Omer-Cooper (1957)], Echinoderes ohtsukai Yamasaki and Kajihara (2012) , E. rex , Echinoderes teretis Brown, 1999 in Adrianov and Malakhov (1999), and Echinoderes serratulus sp. nov. (next description) in having a middorsal spine on segment 4 ( Omer-Cooper 1957; Brown 1985; Adrianov and Malakhov 1999; Lundbye et al. 2011; Yamasaki and Kajihara 2012; SØrensen 2014; Yamasaki and Fujimoto 2014; Herranz and Leander 2016; SØrensen et al. 2016).

Echinoderes regina View in CoL sp. nov. differs from E. annae View in CoL in having an acicular spine laterally on segments 6 and 7 ( E. regina View in CoL sp. nov. has a short acicular spine sublaterally on segments 6 and 7, whereas E. annae View in CoL lacks those) ( SØrensen et al. 2016). Echinoderes regina View in CoL sp. nov. also differs from E. annae View in CoL in lacking midlateral tubules on segment 9 ( SØrensen et al. 2016).

Echinoderes regina View in CoL sp. nov. differs from E. maxwelli View in CoL in the shape of the posterior edge on segment 10 (the edge on segment 10 is not projecting posteriorly in E. regina View in CoL , whereas that is projecting over segment 11 in E. maxwelli View in CoL ) (SØrensen 2014).

Echinoderes regina sp. nov. shares with E. ohtsukai , E. rex , E. teretis , and E. serratulus sp. nov. acicular spines laterally on segments 6 and 7.

Echinoderes regina View in CoL sp. nov. differs from E. ohtsukai View in CoL in the shorter length of lateral terminal spines (76-85 m in E. regina View in CoL sp. nov., 163-190 m in E. teretis View in CoL ), having conspicuous wide tips in the primary pectinate fringes in the middorsal to ventrolateral area on segments 2-9, and lacking any fringed tube ( Yamasaki and Kajihara 2012; Herranz and Leander 2016).

Echinoderes regina View in CoL sp. nov. is similar to E. rex View in CoL in trunk length (451-503 m in E. regina View in CoL sp. nov., 482-528 m in E. rex View in CoL ), but differs conspicuously in having a longer lateral terminal spine (15.2-18.9% of trunk length in E. regina View in CoL sp. nov., 3.8-4.8% of trunk length in E. rex View in CoL ) ( Lundbye et al. 2011).

Echinoderes regina sp. nov. differs from E. teretis in the much longer trunk length (451-503 μm in E. regina sp. nov., 207-264 μm in E. teretis ) and overall trunk shape (slender, with all trunk segments similar in segment circumference in E. regina sp. nov.; plump, with segments 4-6 broader circumferences than other segments) ( Brown 1985).

Echinoderes regina sp. nov. differs from E. serratulus sp. nov. in lacking midlateral tubules on segment 9, in having slender lateral terminal spines, and in the shape of the primary pectinate fringes, especially on segments 2-9 (width of tips of primary pectinate fringe different between middorsal to ventrolateral area and ventromedial area in E. regina sp. nov., similar in E. serratulus sp. nov.).