Paragorgia johnsoni Gray, 1862

JUAN ARMANDO SÁNCHEZ, 2005, Systematics of the bubblegum corals (Cnidaria: Octocorallia: Paragorgiidae) with description of new species from New Zealand and the Eastern Pacific, Zootaxa 1014, pp. 1-72 : 21-25

Paragorgia johnsoni Gray, 1862

( Fig. 10 )

Paragorgia johnsoni Gray, 1862: 125 ; Grasshoff, 1979: 430 (and references therein). Paragorgia boschmai Bayer, 1964: 527 .

Material examined: USNM 73767, 27° 05’ N – 79°40’ W, 608 m, 21 Feb 1984 (Alvin DSR/ V 1335), Bahamas; USNM 100898, 39°52.32’ N – 067°25.19’ W, (col. M. Turnipseed, Delaware II R/V), USA.

Diagnostic characters. Polyps (autozooids) with blunt spindles with irregular ornamentation. Surface cortex sclerites, including the autozooid aperture, are 7­ and 8­radiate sclerites up to 0.06 mm averaging 0.05 mm in length.

Description. Profusely branched colonies up to 900 mm in length (Grasshoff 1979: Fig. 1 ) with terminal branches down to 2–4 mm in diameter (Grasshoff 1979: Figs. 2–3 ). Numerous short, lateral branches arise from the main branches with an irregular but clavate appearance (Grasshoff 1979: Fig. 1 ). Autozooid and siphonozooid polyps located towards one side of the colony (Grasshoff 1979: Figs. 2–3 ). Autozooids clustered in distinct nodules ( Bayer 1964: 527). Autozooid polyp tentacles with blunt spindles, slightly thicker than in most Paragorgia spp., up to 0.08 mm in length, irregularly ornate with conical rays ( Fig. 10 A–B). Surface cortex, including autozooid aperture, with 6­, 7­ and 8­ radiate (predominant 8­radiates) sclerites up to 0.06 mm averaging 0.05 mm in length (0.003 SD, n=10) ( Fig. 10 C–F). Rays nearly symmetrical with smooth surfaces. Surface radiates about 1.57 times longer than wider, averaging 0.03 mm in width (0.002 SD, n=10). Medulla with ornate (oftentimes ramified or forked) spindles up to 0.38 mm in length ( Fig. 10 G; see also Bayer 1964: 531) with smaller forms in the subsurface/outer medulla ( Fig. 10 H).

Morphological variation. P. johnsoni exhibits a great deal of variation mostly in the radiate sclerites from the surface cortex. The presence of 6­, 7­, and 8­radiates in this species is also equaled by P. a r b o re a, though including quite different forms and size ranges in each species. In addition, P. johnsoni and P. a r b o re a are the species with the largest geographical and bathymetrical distributions within the group.

Distribution. Atlantic Ocean, Azores I. (Madeira), Brazil (off Rio de Janeiro), Florida and Bahamas. 800–4152 m ( Bayer 1964; Grasshoff, 1979).

Species comparisons. Grasshoff (1979) revised the type specimens of P. johnsoni and P. boschmai Bayer , including SEM analyses, and concluded that they belong to the same species, therefore P. boschmai is considered a junior synonymy of P. johnsoni . Since Grasshoff’s (1979) work presented clear and straightforward information on species comparisons no further attempts to describe the P. boschmai type specimen were undertaken. See also P. re g a l i s Nutting and P. aotearoa sp. nov.

Paragorgia splendens Thomson & Henderson, 1906 ( Figs. 11–12 )

Paragorgia splendens Thomson & Henderson 1906: 20 ; Bayer 1993: 4. Not Paragorgia sibogae Bayer 1993: 6 .

Material examined. Holotype, BM(NH) 1933.3.13.38, British Museum Natural History, Indian Ocean off Sri Lanka (Investigator expedition st. 284, 7°55’N – 81°47’E, 900 m).

Diagnostic characters. Curved, slim terminal branches (up to 2 mm width). Surface cortex (including calyx surface) containing mostly 8­rayed sclerites (radiate derived, like capstans) up to 0.07 mm in length with rays formed by 4–6 blunt to pointed conical projections ( Fig. 12 B–C).

Description. Fragile, gently bent, slim colonies with branches 1–2 mm in diameter at the portions without autozooids ( Fig. 11 ). Autozooids mostly isolated, occasional clusters of 3–4, along the branches within noticeable spherical calyces ( Fig. 11 ). Autozooid polyp apertures conical, semi­closed, projecting up to 2 mm. Colony easily breakable, most features closely resembling the original description drawing ( Thomson & Henderson 1906). Color pale pink, medulla white. Medulla in the terminal branches visibly perforated by 2– 5 large circular internal canals (see also Bayer 1993). Polyps with blunt spindle­like sclerites in the tentacles, up to 0.1 mm in length, with radially ornate belts of multiple low cones mostly disorganized ( Fig. 12 A). Surface contains highly ornate, 8­radiate­derived, capstan­like sclerites ( Fig. 12 B–C), averaging 0.068 mm (0.006 SD, n=10). Surface sclerites 1.8 times longer than wider, averaging 0.038 mm in width (0.003 SD, n=10). Medulla with long, slim, mostly straight, moderately ornate, spindles up to 0.7 mm in length ( Fig. 12 D).

Morphological variation. The range of sizes is unknown for P. splendens because the original material is very fragmented. The previous study of P. splendens did not include SEM images of sclerites, but variation in both form and size among and within localities is overall low (e.g., Bayer 1993: Fig. 2 vs. Fig. 12 this paper).

Distribution. Only known from the Indian Ocean off Sri Lanka (Investigator expedition st. 284,7°55’N– 81°47’E, 900 m, also station 333, see Bayer 1993).

Species comparisons. A record mentioned by Grasshoff (1979) from the Siboga station 95 (Sulu islands) was further described by Bayer (1993) as P. sibogae . However, it is important to note that P. sibogae Bayer was not included in this study because its description was entirely based on a prepared sclerite slide (after Nutting 1911), without the assignation of a cataloged specimen. See also Paragorgia whero sp. nov.

Figures

FIGURE 1. Geographical locations of the known Paragorgiidae species (see Fig. 2 for New Zealand detail).

FIGURE 2. Map of New Zealand and overall underwater landscape showing the locations and distribution of Paragorgiidae species.

FIGURE 3. Major types of surface cortex radiate sclerites: A – B, 6 ­ radiates; C, 7 ­ radiate; D, 8 ­ radiate.

FIGURE 10. Paragorgia johnsoni Gray (USNM 73767): A, stereo pair of a sclerite from the autozooid polyps (scale 10 m); B, additional sclerites from the autozooid polyps (scales 20 m); C – F, radiate sclerites (C – D are stereo pairs) from the colony surface (scales 10 m); F, additional sclerites from the colony surface and intermediates towards the medulla (scales 10 m); G, sclerites from the colony medulla (scales 100 m); H, sclerites from the subsurface / outer medulla (scales 20 and 30 m).

FIGURE 11. Photograph of a fragment of the holotype of Paragorgia splendens Thomson & Henderson (courtesy of the British Museum­Natural History).

FIGURE 12. Paragorgia splendens Thomson & Henderson, holotype: A, sclerites from the polyps (scale 10 m); B – C, radiate sclerites from the colony surface (scales 10 m) (B is a stereo pair); D, sclerites from the colony medulla (scales 100 m).