Fraseroscyphus hozawai (Stechow, 1931) Stechow, 1931

Song, Xikun, Xiao, Zefeng, Gravili, Cinzia, Ruthensteiner, Bernhard, Mackenzie, Melanie, Wang, Shaoqing, Chen, Jinjing, Yu, Nan & Wang, Jianjun, 2016, Worldwide revision of the genus Fraseroscyphus Boero and Bouillon, 1993 (Cnidaria: Hydrozoa): an integrative approach to establish new generic diagnoses, Zootaxa 4168 (1), pp. 1-37 : 15-19

Fraseroscyphus hozawai (Stechow, 1931) comb. nov.

( Figures 3 A–C, H–I, L–O, 4, 7)

Sertularella sp.? — Inaba, 1890: 293, figs. 26–28.

? Sertularella hesperia Torrey, 1902: 63 , pl. 7, figs. 57–58.

Sertularella solidula — Stechow, 1913: 136, figs. 108–110.

Symplectoscyphus indivisus — Stechow, 1923: 12.

Symplectoscyphus hozawai Stechow, 1931: 179 , fig. 4.— Stechow & Uchida, 1931: 551, fig. 4.— Ling, 1938: 359, fig. 18.— Yamada, 1955: 17, fig. 1.— Rho, 1967: 355, fig. 17, pl. 1, fig. 7; 1969: 10.— Rho & Chang, 1974: 12.— Park & Rho, 1986: 10.— Park, 1990: 80; 1992: 289; 1993: 269; 2010: 115, figs. 64a–c.—Hirohito, 1995: 220, figs. 74a–h, pl. 12, fig. D.— Ruthensteiner et al., 2008: 24.— Tang & Gao, 2008: 318.— Xu et al., 2012: 306; 2014: 682, figs. 580A–B.

Sertularella sinuosa Fraser, 1948: 245 , pl. 28, figs. 20a–d (syn. nov.).— Calder et al., 2009: 988.

Dynamena hozawai — Yamada, 1959: 55.

Symplectoscyphus huanghaiensis Tang & Huang, 1986: 317 , figs. 1a–d (syn. nov.); 1987: 291, fig. 1a–d.— Tang & Gao, 2008: 318.— Xu et al., 2012: 306.

Fraseroscyphus sinuosus — Boero & Bouillon, 1993: 1061, figs. 1A–D. Cairns et al., 2002: 25, 59.

Symplectoscyphus sinuosus — Cairns et al., 2002: 25.

Fraseroscyphus huanghaiensis — Xu et al., 2014: 659, figs. 548A–C.

Type locality. Oma-shimote , Mutsu Bay, Japan.

Type material of Symplectoscyphus hozawai Stechow, 1931 . Three syntypes, attached to a shell of the gastropod Haliotis gigantea Gmelin, 1791 , no gonothecae, no clinging organ, Mutsu-Bay , Oma-Shimote, Japan, 1927. VIII. 18, S. Hozawa. Details: —ZSM 2004 0 228 ( Figure 3 A), lectotype, ethanol stored, formalin fixed, one colony.—ZSM 20041654 ( Figure 3 B), paralectotype, three fragments.—ZSM 20041655 ( Figure 3 C), paralectotype, one fragment.

Type material of Sertularella sinuosa Fraser, 1948 . Lectotype designated by Calder et al. (2009): — Lectotype, SBMNH 347307 ( AHF Holotype No. 95, Figure 3 L), ethanol stored, formalin fixed, off San Pedro, California , USA, no other collection data, one colony, detached from substrate, with two gonothecae, with a clinging organ.— Paralectotype, SBMNH 369460 ( Figure 4 S), ethanol stored, formalin fixed, five colonies, on coralline algae, with a gonotheca, no clinging organ, collection data as for lectotype above.

Type material of Symplectoscyphus huanghaiensis Tang & Huang, 1986 . — Holotype, MBM 102663 ( Figure 3 N–O), ethanol stored, formalin fixed, comprising one nematocyst slide, one colony with eight female gonothecae, one with acrocyst, no clinging organ, collected from intertidal zone creeping on the seaweed Sargassum, Hui Island, Yantai, southern coast of Shandong Peninsula, Yellow Sea , 1982 . X.7, Zhican Tang.

Californian specimens. — MBM 280124 , ethanol stored, formalin fixed, comprising six nematocyst slides, one colony with 10 female gonothecae and three clinging organs, attached to coralline algae, Horseshoe Cove, Bodega Bay , Sonoma County, California, 38.3000ºN, 123.0500ºW, 6 m, 1983 . V.4, Ferdinando Boero.— CASIZ 14588 , ethanol stored, formalin fixed, three colonies with 12 clinging organs, no gonothecae, China Point, Monterey County, California, 1923. IV, Wallace. — CASIZ 14589 , ethanol stored, formalin fixed, two fragments, one male gonotheca, San Diego County, California, 1913, Wallace, re-examination based on images taken by Christina Piotrowski and Kelly Markello (California Academy of Sciences ), originally identified as Sertularella tricuspidata (Alder, 1856) .

Chinese specimens.— MBM 185675 , ethanol stored, formalin fixed, one colony, no gonothecae, 13 clinging organs, Pingshan Island, Lianyungang, Yellow Sea, 35.1667ºN, 119.8667ºE, 1–5 m, creeping on algae, 1975 . XII.17, Yulin Liao.— MBM 185532 , ethanol stored, formalin fixed, one colony, no gonothecae, one of the hydrocladia originating from hydrotheca cavity, 12 clinging organs, intertidal zone, Huiquan Bay , Qingdao, Yellow Sea, 36.0441ºN, 120.3358ºE, 1–5 m, 1981 . XI.14, Zhican Tang.— MBM 280006 , ethanol sample, comprising six nematocyst slides,10 colonies, no gonothecae, with abundant clinging organs, collected from intertidal zone, creeping on seaweed, Huiquan Bay , Qingdao, Yellow Sea, 36.0547ºN, 120.3349ºE, 2014 . VII.26, Xikun Song.— MBM 280007 , ethanol sample, three colonies, no gonothecae, no clinging organ, collected from intertidal zone, creeping on seaweed, Taiping Bay , Qingdao, Yellow Sea, 36.0476ºN, 120.3425ºE, 2014 . VII.25, Xikun Song.— MBM 280015 , ethanol sample, one colony, no gonothecae, with clinging organs, collected from intertidal zone, creeping on seaweed, Huiquan Bay , Qingdao, Yellow Sea, 36.0564ºN, 120.3309ºE, 2012 . VIII.3, Xikun Song , Jinjing Chen , and Ning Yuan.— MBM 280266 , ethanol sample, comprising two nematocyst slides, three colonies, no gonothecae, no clinging organ, attached to seaweeds, intertidal zone, Huiquan Bay , Qingdao, Yellow Sea, 36.0547ºN, 120.3349ºE, 1–5 m, 2012 . VIII.4, Xikun Song , Jinjing Chen and Ning Yuan.— MBM 280267 , ethanol sample, comprising two nematocyst slides, two colonies, no gonothecae, no clinging organ, intertidal zone, Huiquan Bay , Qingdao, Yellow Sea, 36.0547ºN, 120.3349ºE, 1–5 m, attached to algae, 2012 . VIII.3, Xikun Song , Jinjing Chen and Ning Yuan.— MBM 280291 , ethanol sample, two colonies, a hydrocladium origin from within the hydrothecal cavity, no gonothecae, no clinging organ, attached to seaweeds, east Zhu Island, Rushan , Weihai, Yellow Sea, 36.7315ºN, 121.5998ºE, 1–5 m, 2013 . VIII.3, Zhongmin Sun.— MBM 280292 , ethanol sample, two colonies, no gonothecae, no clinging organ, attached to algae and bryozoans, intertidal zone, Huiquan Bay , Qingdao, Yellow Sea, 36.0547ºN, 120.3349ºE, 2012 . VIII.4, Xikun Song , Jinjing Chen and Ning Yuan.

Measurements. Full details are given in Table 6.

Species Collecting locality Internode Hydrothecal Gonotheca (mm) Nematocyte

(mm) abcauline Height, width, distal capsule (µm) length, width neck length Type I (length, (mm) width); type II (length, width)

F. hozawai California (type) 0.33–0.43 0.36–0.39, – –

0.12–0.16

California (CASIZ) 0.34–0.47 0.34–0.48, Ƌ, 1.52, 0.59, 0.19 –

0.09–0.23

California 0.34–0.50 0.34–0.55, ♀, 1.25–1.68, 0.59–0.86, 6.5–8.0,1.5–2.2; (MBM 280124) 0.16–0.23 0.16–0.36 3.4–5.8, 1.4–1.8 China ('type') 0.30–0.45 0.30–0.41, ♀, 1.23–1.36, 0.43–0.70, 8.7–9.4, 2.8–3.0; 0.16–0.17 0.23–0.25 5.2–5.8, 1.6–1.9 Japan ('type') 0.25–0.43 0.32–0.34, absent –

0.13–0.18

Korea ( Park 2010) 0.22–0.25 0.31–0.38, Ƌ, 1.35, 0.63, 0.15 –

0.10–0.17

F. macrogonus New Zealand (type) 0.24–0.50 0.26–0.34, Ƌ, 1.20–1.72, 0.63–1.10, 11.0–12.8, 2.5–3.8; 0.12–0.16 0.13–0.18 4.1–4.6, 1.2–1.8 F. irregularis New Zealand (type) 0.11–0.27 0.20–0.27, Ƌ, 1.14–1.20, 0.51–0.80, 8.8–9.8, 1.5–2.4; 0.10–0.16 0–0.09; 4.3–5.1, 1.4–1.6 ♀, 1.06–1.21, 0.53–0.65,

0.06–0.09

Description. Trophosome. Colonies creeping on algae ( Figure 4 A) or bryozoans, perisarc thick, hydrocaulus monosiphonic, erect, slightly zigzag, with one to two transverse annulations at base, unbranched or infrequently branched ( Figure 4 B), hydrocladium growing directly out of hydrocaulus, no apophysis ( Figure 4 B) or origin from within the hydrothecal cavity; hydrocaulus and hydrocladium with regular and oblique nodes, each internode slightly constricted at the end and bearing a hydrotheca. Hydrothecae generally arranged alternately in two, lateral, longitudinal rows, almost in one plane ( Figure 4 E–G, J) or sometimes forming an angle ranging from 60º to 90º ( Figure 4 C–D); hydrotheca tubular, curving outwards proximally, then upwards distally, almost perpendicular to hydrocaulus, with fine transverse lines on surface ( Figures 3 L–M, 4P–R), a third to two thirds of adcauline part adnate, margin with three cusps, one adcauline and two lateral abcauline, abcauline cusps much larger; no intrathecal teeth observed; operculum composed of three flaps forming a pyramid, the abcauline flaps are much larger; retracted hydranth with poorly developed abcauline caecum ( Figure 4 S–T).

Clinging organ. Clinging organs irregularly splayed on mature hydrocauli, like rayed hemispherical disks, each composed of two to six repeated dichotomous lobes of varying developmental stages ( Figure 4 K–N), opening distally with very thin perisarc ( Figure 4 M–N); each lobe can elongate and divide into secondary lobes in a mature clinging organ ( Figure 4 N). Accompanying each clinging organ, one to six annulations usually located on and near node ( Figure 4 L–N), hydrothecae becoming infrequent and tending to arrange irregularly, e.g., forming an angle ranging from 60º to 90º.

Gonosome. Gonotheca pedicellate, all gonothecae examined in this study origin from within the hydrothecal cavity at the lower part of hydrocaulus ( Figure 4 E–J), with fine lines on some regions of the surface ( Figures 3 N– O, 4F, I), with a short distal neck. Male gonotheca ( Figure 4 E–F) long, orbicular ovate with short, wide neck, female gonotheca cylindrical ( Figures 3 N–O, 4G–J) with a long, thin neck.

Nematocysts. Two types, only varying in length ( Figures 3 H–I, 4U–X), capsules spindle-shaped. Discharged nematocysts of both types ( Figure 3 I) have a well-developed shaft and thread (Chinese samples). Spines cannot be clearly identified using light microscopy.

Distribution. Only reported from the temperate regions of the eastern and western sides of the North Pacific ( Figure 7 ), distributed near the coast at depths of 1– 20 m. Northwest coast of the Pacific: Shandong, Jiangsu and Zhejiang, China ( Lin 1938; Tang & Huang 1986; Tang & Gao 2008; Xu et al. 2012); Daejin, Jumunjin, Imwon, Pohang, Mipo, Mijori, Yeonhwado, Yejakdo, Dolsan Bangjukpo, Jindo Hoedong, Jeopdo, Dolsan, Jindo, Jeopdo, Daedundo, Biin, Seogwipo, Supseom, Korea ( Rho 1967; Park 2010); Mutsu Bay, Oma-Shimote, Sagami Bay, Japan ( Inaba 1890, Stechow 1913, 1923, 1931; Stechow & Uchida 1931; Yamada 1959; Hirohito 1995; Ruthensteiner et al. 2008). Northeast coast of the Pacific: Off San Pedro, California, Santa Rosa Island; Smugglers Cove, Santa Cruz Island; Cat Rock, Anacapa Island; Laguna Beach, low tide; White Cove, Santa Catalina Island; off San Nicolas Island; west of Dutch Harbor; Tanner Bank; off Point Loma; South Bay, Cedros Island; north of Dewey Channel, Lower California; Dewey Channel, opposite San Eugenio Point; Horseshoe Cove, Bodega Bay, Sonoma County, California ( Torrey 1902; Fraser 1948; Boero & Bouillon 1993; Calder et al. 2009).

Lectotype designation. —Lectotype, ZSM 20040228 ( Figure 3 A), an infertile colony in ethanol (the largest colony of the syntypes).—Paralectotype, four infertile fragments on slide ZSM 20041654 and ZSM 20041655 ( Figure 3 B–C).

Remarks. We synonymise Sertularella sinuosa Fraser, 1948 and Symplectoscyphus huanghaiensis Tang & Huang, 1986 with Fraseroscyphus hozawai (Stechow, 1931) , after having examined the type material and some specimens from type localities, because they share the same characters of hydrotheca, gonotheca and clinging organ, and have the same nematocyst capsule types. Sertularella hesperia Torrey, 1902 (type locality, California) is a possible doubtful synonym for F. ho z a w a i, because its appearance in the original description matches the morphology of the trophosome in the type material of Sertularella sinuosa (synonym of F. hozawai ). In its original description, Torrey (1902) noted the morphological differences between Sertularella hesperia and Symplectoscyphus tricuspidatus , and provided an illustration (Figure 58) for a fragment with characteristic features. However, the remaining illustrations of the hydrothecae (Figure 57) were easily confused with S. tricuspidatus . Nutting (1904) compared Torrey's description with his S. tricuspidatus samples, and considered them as synonymous. Unfortunately, the type material of S. hesperia could not be found in the invertebrate collections of the University of California (Berkeley) and Department of Invertebrate Zoology and Geology, California Academy of Sciences (CASIZ). Therefore, the relationship of S. hesperia with F. hozawai remains unknown.

As a result of these synonyms, the current distribution of F. hozawai comprises the temperate regions of both the east and west coast of the Northern Pacific, showing a transoceanic distribution pattern. Samples from each side vary slightly and can be distinguished into separate populations: the hydrothecae and gonothecae from the eastern population are slightly larger, while the dominant nematocyst type (type I) is slightly smaller; moreover, lines on the western population are much more common and dense.

All gonothecae examined in this study arise from within the hydrothecal cavity. Inaba (1890, Figure 27) drew two gonothecae for this species (as Sertularella sp.?), which might be the only reported samples with gonothecae growing directly out of the hydrocaulus. Unfortunately, Inaba (1890) did not draw the pedicle of the gonothecae clearly. This character should be checked when examining future samples.

Figures

FIGURE 3. Type samples, nematocyst and SEM scanning images. (A – C), Fraseroscyphus hozawai, A, lectotype, ZSM 20040228, paralectotype, ZSM 20041654, 20041655; (D – E) F. irregularis, (D) NMV F 57894, the arrow showing the lectotype, the others paralectotype, (E) paralectotype, NMV F 57941; (F – G) F. macrogonus, (F) NMV F 57892.1, the arrow showing the lectotype, the others paralectotype, (G) NMV F 57892.2, paralectotype. (H – I), nematocyst capsules of F. ho z aw ai, (H) from California, MBM 280124, (I) from China, MBM 280006, 280266, 280267, H 1 – H 10, I 1 – I 4, type I, H 11, I 5 – I 6, type II, I 4 and I 6 discharged. (J) F. irregularis, NMV F 57939.1, J 1 – J 3, type I, J 4 – J 5, type II; (K) F. macrogonus, NMV F 57892.1, K 1 – K 3, type I, K 4 – K 5, type II. (L – M) SEM images F. hozawai, (L) from California, lectotype, SBMNH 347307, (M) from China, MBM 280292. (N – O), fine groves on a female gonotheca (deformed) with acrocyst, from China, MBM 102663. Scale bars: A – C = 1 cm; D – G = 1 cm; H – K = 10 µm; L – M = 150 µm; N = 500 µm; O = 100 µm.

FIGURE 4. Fraseroscyphus hozawai. (A) colony adhering to Sargassum alga; (B) hydrocaulus and hydrocladium; (C – D) hydrothecae on hydrocaulus forming an angle; (E – F) male gonothecae, hydrothecae almost in one plane; (G – J) female, G – H and I – J from two separate colonies; (K – N) clinging organs showing developmental stages; (O) stolons possibly growing from an over developed clinging organ; (P – R), fine lines on hydrothecae; (S – T) abcauline caecum; (U – X), nematocyst capsules. Samples from California: D, G – H, K, P, W – X, MBM 280124; E, CASIZ 14589; S, SBMNH 347307. Samples from China: A – B, I – J, MBM 102663; C, MBM 280267; L – O, T, MBM 185675; R, U – V MBM 280266. Sample from Japan: Q, ZSM 20041654, paralectotype. Sample form Korea: F, redrawn after Park (2010). Scale Bars: A = 1 cm; B – O = 0.5 mm; P – T = 0.3 mm; U – X = 5 µm.

FIGURE 7. Worldwide distribution of Fraseroscyphus.