Flabellum chunii Marenzeller, 1904

Altuna, Álvaro, 2013, Scleractinia (Cnidaria: Anthozoa) from ECOMARG 2003, 2008 and 2009 expeditions to bathyal waters off north and northwest Spain (northeast Atlantic), Zootaxa 3641 (2), pp. 101-128 : 116-117

Flabellum chunii Marenzeller, 1904

( Figs. 5 A–D, tables 1−3)

Flabellum chunii Marenzeller, 1904: 274 , pl. 18, figs. 14, 14a −14b.—Zibrowius 1980: 145, pl. 76, figs. A–N.—Monteiro Marques & Andrade 1981: 88.—Cairns & Chapman 2001: 36 (tab. 1).—Brito & Ocaña 2004: 422, pl. 98, figs. A–B.

Material examined. Galicia Bank: Stn. G 4, 750 m, one specimen; Stn. V 4, 732 m, 19 specimens; Stn. V 5, 877 m, 10 specimens, two of them dead; Stn. V 6, 766 m, 12 specimens, two of them dead; Stn. V 7, 924 m, six specimens, five of them dead; Stn. R 2, 614 m, one dead specimen.

Description. Corallum solitary and unattached, flabellate, big (up to H= 4.8 cm), straight, laterally compressed, sometimes with a small peduncle and a minute basal disc. Wall glossy, pearly. Costae poorly developed, obscured by abundant transverse growth marks that give specimens a corrugated appearance. Basal processes occasionally present (fig. 4A, C). Calice of largest specimen examined forming a 180º apparent arch 11.8 cm long, with a projection in the plane of GCD= 5.8 cm and LCD= 2.9 cm. Septa up to 271, not exsert, arranged in six complete cycles (192 septa) and a S7 incomplete (79 septa). Septa thin, descending vertically into fossa; S1−S4 subequal in width; S5–S7 thinner; S1−S4 and a few S5 (55 septa), mainly from the edges of GCD, merge with columella deep in the fossa. Septa with upper margins smooth, and septal faces with scarce small pointed granules. Inner edges straight and thickened near columella (S1−S4), or slightly sinuous (S5−S7). Columella very deep, narrow, trabecular. Corallum pink to light purple, brownish, or even white in small specimens.

Remarks. The smallest specimen examined (H= 1.1 cm, GCD= 1.5 cm, LCD= 0.7 cm) has a minute basal plate at the end of the peduncle. With this size it has 64 septa in six cycles (S1−2>S3>S4>S5), with S1−S4 complete and 16 S5 placed principally in half-systems adjacent to the principal septa, close to the protosepta, with their development accelerated. From them, only S1 and S2 reach the columella merging with it. S1−S2 are subequal in length, S3 slightly shorter, and the S4 reach into the middle of S3; S5 are rudimentary. Some specimens are almost circular in lateral view (fig. 5C).

Most specimens are encrusted by Lumbrineris (fig. 5A–D). Corrosion can be very significant and, as said by Marenzeller (1904), may occur in almost all the specimens from a station. The 17 specimens from stn. V4 were corroded, eight from ten specimens collected on stn. V5 (only two small corallites without the worm), one from stn. G4, all from stn. V6, and three from six specimens collected on stn. V7 (all are small coralla). It could be argued that the worm colonizes the corallum from a certain size upwards, but this needs further observations. The corrosion by Lumbrineris was observed previously between 160−623 m depth (Zibrowius 1980). In the Galicia Bank specimens corroded were collected at deeper depths, in specimens from stn. V7 (924 m). Some corallites have also corrosion by Turridae (fig. 5D), that was known in specimens from Azores (Zibrowius 1980).

Flabellum chunii is a coral of a north-eastem Atlantic distribution that was traced by Zibrowius (1980), and whose northernmost published record was at the south of Portugal (38º50’N). According to new data given herein, its geographic range is extended significantly. It is a common species in the Galicia Bank, and was also obtained therein during the 1987 SEAMOUNT 1 expedition (Zibrowius, com. pers., unpublished).

Figures

FIGURE 5. Flabellum chunii Marenzeller, 1904 (Galicia Bank). A – C) Coralla in side view with corrosion by Lumbrineris (A, H = 4.83 cm; B, H = 3.9 cm; C, H = 3.7 cm; A, stn. V 6; B – D, stn. V 4). D) Detail showing circular marks of corrosion by Turridae near calicular margin (specimen B). Flabellum macandrewi Gray, 1849 (stn. V 1, Le Danois Bank). E) Corallum in side view (GCD = 2.39 cm; LCD = 2.22 cm; H = 1.86 cm). F) Calicular view of the same specimen. G) Fragment. Eguchipsammia cornucopia (Pourtalès, 1871) (stn. S 7 V, Le Danois Bank). H) Whole specimen in side view. I) Calicular view of the same specimen (GCD = 1.76 cm). J) Calicular view of a dead specimen showing intratentacular budding, with formation of three new calices and three new columellae. Scale bar: A – B = 3.0 cm; C = 2.0 cm; D = 0.9 cm; E – G, J = 1.0 cm; H = 2.5 cm; I = 1.5 cm.