Eugorgia daniana Verrill, 1868

Horvath, Elizabeth Anne, 2019, A review of gorgonian coral species (Cnidaria, Octocorallia, Alcyonacea) held in the Santa Barbara Museum of Natural History research collection: focus on species from Scleraxonia, Holaxonia, Calcaxonia - Part II: Species of Holaxonia, families Gorgoniidae and Plexauridae, ZooKeys 860, pp. 67-182 : 67

Eugorgia daniana Verrill, 1868 Figures 4, 5, 6, 7

Eugorgia daniana Verrill, 1868a; 1868b [1869]: 409-410; pl V, fig. 14; pl VI, fig. 7. Bielschowsky 1918: 45. Kükenthal 1924: 346. Bielschowsky 1929: 181. Stiasny 1951: 65. Prahl et al. 1986: 17. Breedy et al. 2009: 17-20.

Type locality.

Central America: Pearl Islands; Costa Rica, Gulf of Nicoya.

Type specimens.

Syntype series ( Breedy et al. 2009): MCZ 723 [dry]; MCZ 7080 [dry]; YPM 1551a-d and 1629a, b [dry]; YPM 5146 [dry].

Material examined.

~10 lots (see Appendix 1: List of material examined). Was unable to examine the type specimens, but utilized descriptions and images noted in Breedy et al. (2009).

Description.

Collection lot examined, shown in Figures 4 (whole colony), 5 (branch magnified to show prominent polyps), 6 and 7 (sclerites, light microscopy and SEM, respectively), generally matches description given in Breedy et al. (2009: 17-20, 35). Color of branches tended generally to dark orangey-red, with coenenchyme base of polyp-mounds red, upper portion of polyp-mounds gold-orange; overall impression is that colony is basically red. Sclerites (Figure 6) either bright to deep red or yellow-green in color, mixed together. In some instances an individual sclerite can be bicolored (red at one end, other end yellow-green); sclerites as double discs, relatively large; inner wheels thin, with sharp edges, outer ones terminal, not half as large, also sharp-edged (Figure 7A) (see remarks below).

Common name.

Red gorgonian ( Gotshall 1998).

Distribution.

As recorded by Verrill (1868a and 1868b [1869]) found in Panama and the Pearl Islands, 11-15 m (this according to FH Bradley); also seen in the Gulf of Nicoya, Costa Rica (JA McNiel). Other notations indicated that it could extend down to Peru (see Breedy et al. 2009: table 4 for full, known distributional range). Based on one specimen, USNM, 57302, taken in Escondido Bay, near San Diego County, San Diego, California, the overall range would extend from San Diego, California (at least), through Central America, possibly down to South America. Assuming E. daniana is a distinct species, it is then present in Central and Lower Gulf of California, living in the same area with Eugorgia aurantiaca Horn, 1860. Thus, southern-most end of the California Bight may be the northern-most limit (and as a separate species, E. daniana extends just a bit further north and further south than E. aurantiaca ).

Biology.

Generally found on offshore reefs and islands; prefers clean, plankton-rich waters and generally found at depths to ~30 m ( Gotshall 1998).

Remarks.

While description generally matches that given in Breedy et al. (2009), I would make the following caveats: first, the colony color as described by Verrill was as a bright yellow, streaked and blotched with dark red on both branches and polyps. The color seen in specimens here lies somewhat intermediate to that described in Olvera et al. (2018) for E. aurantiaca and E. daniana ; overall, dark orange-red. Divers have anecdotally described the living colony as having slender red branches, with white (colorless) polyps.

For Verrill (1868b [1869]: 411), "In the mode of branching, the size and structure of the branchlets, and color ( E. aurantiaca ) closely resembles ( E. daniana )," which he separated primarily on the basis of the very different size and form of the sclerites, especially of the double discs; for Verrill, these were the defining feature in designating this species as distinct from E. aurantiaca . In my examinations, the larger, “sharp” double discs were always present (distinctive of E. daniana ). However, in a few specimens used for comparison, labeled as E. aurantiaca , the presence of sharper double discs was noted (misidentified specimens?); this condition was contrary to the generally slightly smaller size of the double discs that are commonly seen in E. aurantiaca , where discs are described as being generally rounded, inner and outer discs very close together. In subsequent comparisons, the polyps were not always so densely packed in E. daniana as was seen in E. aurantiaca (no overlapping of polyps). With regards to branching pattern, specimens of E. aurantiaca often had a far more distinctive (and decidedly symmetrical) pattern of pinnate branching, with majority of secondary branches (branchlets) of similar length, all generally lying in one plane as compared to that seen in E. daniana . SBMNH specimens of E. daniana nearly always had their terminal-most, thin, slender branchlets curving out of one plane. Without molecular investigation, there is no clear, definitive confirmation that Eugorgia aurantiaca and Eugorgia daniana are indeed separate species. There are many overlapping features, in terms of potential branch pattern, form, and size of sclerites, and general color. The differences could be accounted for as variation within one species. However, examination of numerous examples of both those identified as E. aurantiaca and E. daniana allowed for observation of the differences in the double discs that Verrill used to distinguish these two species (differences can be obvious). For now, it seems appropriate to recognize two separate species until further studies prove otherwise.

Of note is that WoRMS Data Base ( Cordeiro et al. 2018b) does list E. aurantiaca and E. daniana as separate species, but that E. daniana has been accepted as Leptogorgia daniana . Very few species of Leptogorgia ( L. ramulus Milne Edwards & Haime, 1857, is one of few) display the shorter branch lengths seen consistently in species of Eugorgia nor the irregular and pinnate branching of the Eugorgia , which are morphological characters; it is understood that this acceptance is based on the molecular work that was done by Soler-Hurtado et al. (2017). Of note is the rationale for this genus change, with Soler-Hurtado et al. (2017) noting the 1999 ICZN Principle of Priority (Article 23). In the work of Olvera et al. (2018), this species is listed as a species of Eugorgia and is not included in the list of Leptogorgia species that are discussed.