Eunicea tayrona, Sánchez, 2009

Sánchez, Juan Armando, 2009, Systematics of the candelabrum gorgonian corals (Eunicea Lamouroux; Plexauridae; Octocorallia; Cnidaria), Zoological Journal of the Linnean Society 157 (2), pp. 237-263 : 254-258

EUNICEA TAYRONA SP. NOV. ( FIGS 9–11 )

Eunicea sp. : Cobar et al., 1997: 62.

Eunicea sp. 2 Sánchez & Wirshing, 2005: 516.

Holotype: USNM 100646 , Riding Rock Reef , leeward reefs, 12 m, San Salvador, Bahamas, 15.viii.1999, col. J.A. Sánchez.

Paratypes: ICN-MHN-CO-098, (Q-1), El morrito, Santa Marta Bay (front of Punta Betín), Caribbean coast of Colombia, 4.iii.1996, rubble substrate in rocky littoral 6 m, col. J.A. Sánchez (secondary chemical compounds of the same colony in Cobar et al., 1997) . USNM 97733 (64), Isla Tesoro , Rosario islands, Caribbean coast of Colombia, col. J.A. Sánchez & A. Ramirez , 10.xii.1992; Outer slope 16 m; ICN-MHN- CO-091 (B-20), Banco Bushnell, continental platform Caribbean coast of Colombia, col. J.A. Sánchez , mixed plateau 12 m. INV-CNID-388, (E-173), Cayos de Bolivar (Courtown Cays) (12° 24′ 25″N, 81° 29′ 24″W), Colombian Caribbean, 24.v.1995, Leeward terrace 12 m, col. J.A. Sánchez. IM-ANDES 228, Isla Tesoro , Colombian Caribbean, 12.x.1992, fore-reef terrace 16 m, col. J.A. Sánchez.

Description: Colonies tall and bushy up to 1.3 m in height. Thin branches 3–5 mm in diameter or less at the branch tips ( Fig. 9 ). Small and brown (probably because of zooxanthellae) polyps. Numerous low calyces disposed uniformly with a projecting lower tip. Middle layer sclerites blunt and usually with less than 1 mm in length ( Fig. 10A–D ). A clear dark core in the sclerite noted under the light microscope. Axial layer composed of a diverse array of ornate forms of capstans and spindles usually purple-coloured and up to 0.11–0.17 mm in length ( Fig. 11E ). Polyp armature composed of ornate sclerites (0.14–0.32 mm in length) as well as little flat rods (0.06–0.12 mm; e.g. Fig. 11D ). The surface layer contains tiny club sclerites (foliate to torched) with short handle ( Fig. 11A– C ), which are the shortest observed amongst Eunicea species.

The holotype is a grey-brown colony of about 25 cm in height, which was branching in one plane when collected ( Fig. 9 ). All Caribbean samples have low variation with respect to both middle layer spindles and the tiny club-sclerites from the outer layer. The species was named after the extinct Colombian tribe Tayrona distributed in the Caribbean coast.

Particular features: Surface layer with tiny and foliate club sclerites of 0.07–0.11 mm in length, mostly small sizes.

Distribution and habitat: Florida, Bahamas, Lesser Antilles, San Andrés and Providencia Archipelago, and the Caribbean coast of Colombia (probably throughout the Caribbean). Shallow semi-exposed shallow reefs, leeward terraces, and slope edge between 2 and 25 m in depth.

Additional examined material: ICN-MHN-CO-078 (E-155), Bolivar Cays (Courtown) (12° 24′ 25″N, 81° 29′ 24″W), Colombian Caribbean, 24.v.1995 , Leeward terrace, 12 m, col. J.A. Sánchez. ICN-MHN-CO-095 (N-12), Serrana bank, Colombian Caribbean, col. J.A. Sánchez, shallow patch reef 8 m (0.8 m height). INV- CNID-371, (E-84a), Albuquerque Cays (12° 69′ 17″N, 81° 53′ 59″W), Colombian Caribbean, 3.vi.1994 , forereef terrace, col. J.A. Sánchez. USNM 55064, Turks and Caicos Islands, Grand Turk Island; 21°21′42″N, 070°57′18″W, 7–8 m, col. Pillsbury R / V University of Miami , 19.vii.1971 .

ADDITIONAL SPECIES COMPARISONS

Additional evidence, independent from that used in the systematic analysis, from some natural history traits was gathered to further validate the ‘species’ status in Eunicea . The compared pairs, as previously mentioned, were E. tourneforti – E. cf. clavigera , E. fusca – E. tayrona sp. nov., and E. succinea – E. succinea plantaginea morphotype. Even though some differences were found in the latter pair, the information was not completely conclusive and it is still considered the same species. However, this case was useful to control for the differences between the other species pairs, where straightforward differences were noted.

Variation in colonial size and module array

The cover index, an indicator of the colonial architecture (e.g. Jordan & Nugent, 1978; Sánchez et al. 1997), was different only between E. fusca and E. tayrona sp. nov. (one-way ANOVA with log [x+1] transformed data, F = 18.78, d.f. = 66, P <0.00001; homogeneous variances: F = 0.64, P = 0.88). It is important to note that E. fusca grows mainly through asexual propagation; therefore significant differences in colony size were expected. There was a significant correlation between the projected shade and height in all the species (P << 0.02) exhibiting similar trends in terms of slope and r 2 amongst pairs (data not shown). Actually, there were no differences between the adjusted means of the analysis for the different species pairs analyzed (P> 0.05), but there were differences in the slopes between E. fusca and E. tayrona sp. nov. (analysis of covariance with log [x+1] transformed data: Shared slope = 17.4, d.f. = 64, F = 5.02, P <0.05). Therefore, the differences in colony size were present just in the case where asexual propagation was important in the life history traits, as in the case of E. fusca . The module and associated structures (i.e. calyx) were highly variable amongst Eunicea species. Means and ranges of calyx length and density varied between pairs of species ( Table 3). These differences were expected, even amongst morphotypes, because amongst the characteristics of E. succinea forma plantaginea are enlarged and tampered branches that may predict differences in calyx density. Another particularity of each species was the diameter of the branch in the very last portion of the tip. Interestingly, in some species the branch tip was thicker or more clavate than a few centimetres below whereas in others it was the same or even narrower (tampering) as expected. The morphotypes ( E. succinea ) were the only ones that exhibited the same pattern of cross sectional area at the tip. Differences within the other pairs were evident ( Table 2).

Female fecundity

The analysed species were gonochoric, separate sexes, with eggs and spermaries showing spheric to lenticular shapes. Gonads were placed in rows in the base of the septa and closely intermingled with mesenteric filaments. There were some problems with the data from male gonads. These data were highly variable in number and volume per species; therefore it was not possible to afford comparisons. Unfortunately, Eunicea fusca samples were not fertile enough to recognize gonads. Otherwise, eggs were bright ochre with a dark pole in the species from the Euniceopsis subgenus or a bright yellowish colour in Eunicea s.s. Overall, all the species had a large range of variation ( Table 4) and non-normal distributions. Most of the eggs were of small sizes and just a few (usually less than five) were notably larger than the rest. Euniceopsis species had a higher number of eggs per polyp than the species of Eunicea s.s. (30–80 vs. 17–20: Table 4). The number of eggs, volume per gonad polyp, and egg diameter was significantly different between Eunicea tourneforti and E. cf. clavigera ( Table 4), which corroborated that they are different species. Between the morphs of E. succinea there were no consistent differences. The mean values of number of eggs per polyp did not exhibit significant Results from comparisons between pairs of species through the Mann–Whitney nonparametric test for unequal independent samples (one tail normal approximation, Z; e.g. Zar, 1996) from the same parameters. Any of the pair had homogeneous variances (F between variances, P << 0.05).

Results from comparisons between pairs of species through the Mann–Whitney nonparametric test for unequal independent samples (one tail normal approximation, Z; Zar, 1996) from the same parameters. None of the pairs had homogeneous variances (F between variances, P << 0.05).

differences whereas volume per gonad and diameter of eggs did so ( Table 4).

Figures

Figure 9. Photographs of Eunicea tayrona sp. nov. holotype (USNM 100646). A, underwater views of the colony alive, Riding Rock Reef, Leeward terrace, 12 m, San Salvador, Bahamas, 15 August 1999; B, dry specimen (calliper open at 2 cm) and detail; C, photo of the Eunicea fusca holotype and its club-like sclerites, museum of Turin (photos by and courtesy of Carlo Cerrano, University of Genoa).

Figure 10. Scanning electron micrograph images from sclerites of Eunicea tayrona sp. nov. holotype (USNM 100646). A–D, sclerites (ornamented spindles) from the middle layer (scale bars = 0.1 mm). A is a stereopair. B and D are details of wart ornamentation (scale bars = 0.01 mm); E, rod sclerites from the anthocodial crown/armature of the polyps (scale bars = 0.01 mm).

Figure 11. Scanning electron micrograph stereopairs from sclerites of Eunicea tayrona sp. nov. holotype (USNM 100646). A, sclerites (ornamented spindles) from the middle layer (scale bar = 0.1 mm); B, detail of wart ornamentation from A (scale bar = 0.02 mm); C, axial layer sclerite (scale bar = 0.01 mm); D, club sclerite from the surface layer (scale bar = 0.01 mm).