Eugorgia ljubenkovia, Horvath, Elizabeth Anne, 2019

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 ljubenkovia sp. nov. Figures 11A, B, 12A, B, 13 A–C

Type locality.

Isla Cedros, Baja, Mexico.

Type specimens.

Holotype Santa Barbara Museum of Natural History, SBMNH 422333.

Material examined.

~5 lots (see Appendix 1: List of material examined).

Diagnosis.

Colony an obvious whip-like form, no apparent holdfast, with minimal to no branching (not common to genus), branches fairly slender, with both branch ends pointed; sclerites double-disc spindles, with disc edges quite angular and sharp, characteristic of genus.

Description.

Colonies (Figure 11A) incomplete, with exception of one (total strand length of complete one, 58.5 cm; length of largest colony fragment, ~37 cm); diameter 1.0 mm (largest diameter up to 3.0 mm, when polyps included); few with tiny holdfast; long, thin, stiff, wiry strands, none or very few primary or secondary branches (unusual for species in this genus); what branches are present come off at right angles to main stem, then curve some five cm distant or more from branching point; branch pattern (one colony) more dichotomous or lateral. Tips of branches (both ends) terminate in small arrowhead configuration. Coenenchyme very thin; axis visible through it in some areas; color of colonies generally pure white, light creamy beige to very, very pale pink, both coenenchyme and polyps; axis red-gold, with greenish cast. Small polyp mounds (no more than 1.0 mm tall, 1.0-1.5 mm broad at base) moderately prominent, rounded, conically broad bumps arranged in nearly opposite (occasionally alternate) pattern, lateral, giving strands flattened appearance from front to back (closer examination revealed polyps on all sides); very thin ridge line (longitudinal ridge) runs down middle of both “front” and “back” of branch; appears as bare “thread,” slightly raised; overall, polyps give branches a distinct zig-zag edge on lateral sides. Polyps (Figure 11B) sit very close together, bases touching; greatest distance between polyps ~1.0 mm. Polyp aperture oval-shaped to thin slit, aligned with long axis of branch. Sclerites (Figures 12, 13) small; predominant type are double disc spindles (Figure 13B), with disc edges quite angular and sharp (common in species of Eugorgia ); also, slightly longer, symmetrical spindles (more typical of species in genus Leptogorgia , Figure 13C) and occasionally, crosses (quadriradiates); all are colorless.

Etymology.

Proposing Eugorgia ljubenkovia , to honor John Ljubenkov, a southern California cnidarian biologist, colleague and friend of many Southern California Association of Marine Invertebrate Taxonomists (SCAMIT) members.

Common name.

John’s wire gorgonian.

Distribution.

Known from collection events undertaken by staff of Orange County Sanitation District and one lot taken in South Bay, Isla Cedros ('Velero IV’) in 1949; thus, at this time, known from southern California and northernmost Baja, Mexico.

Biology.

Moderate occurrence, indicated by OCSD collection events; not occurring at great depth (~30-35 m). Hydroids (fuzzy mass) attached to bare axis on one colony (SBMNH 472233); elsewhere on same colony, barnacle galls, barnacles completely covered with gorgonian’s coenenchyme.

Remarks.

All colonies have shape of a thin, whip-like Leptogorgia species, and may exhibit the same presumed lifestyle as that of Leptogorgia filicrispa Horvath, 2011 or that of species in the genus Thesea Duchassaing & Michelotti, 1860. However, sclerites most distinctive in being largely double discs, characteristic of species in the genus Eugorgia . Originally, was tentatively identified as a possible Heterogorgia Verrill, 1868c by J Ljubenkov; these specimens did not show the characteristic collaret, point and thorn sclerites of that genus (and that genus does not display distinct double discs, as seen here). Originally, SBMNH 422333 was shelved with specimens of the genus Thesea ; despite the long, thinner branch strands and possible lifestyle similarity, no large spheroidal bodies, characteristic of Thesea were found. Also, this species (in five lots), is not additional material of the species L. filicrispa (Horvath, 2011), as jagged double discs are not seen in that species, and sclerites in that species can be variably colored. This species is a unique mix of colony form seen in some Leptogorgia with the sclerites of a Eugorgia . The long, thin wiry condition of the stems may be the result of environmental circumstances, involving both substrate (sandy or soft bottom sediment) and water flow. From examination of all specimens, it seems possible that some strands have no attachment base, but instead have terminal tips at both ends of strand. Further in situ work would need to be undertaken to document the environmental conditions under which this species lives.