Leptogorgia enrici, Hernández & Gómez-Gutiérrez & Sánchez, 2021

Hernandez, Osvaldo, Gomez-Gutierrez, Jaime & Sanchez, Carlos, 2021, Three new species of the sea fan genus Leptogorgia (Octocorallia, Gorgoniidae) from the Gulf of California, Mexico, ZooKeys 1017, pp. 1-20 : 1

Leptogorgia enrici sp. nov. Figures 1 , 6 , 7 , 8E-G

Material examined.

Holotype. NMNH-1638560: dry, San Esteban Island (northwest rocky point), Sonora, Mexico (28°43.564'N, - 112°36.799'W), 24 m depth, in situ temperature 19 °C, 01 November 1999, collector Carlos Sánchez. Paratypes. NMNH-1638561: dry, San Esteban Island (northwest rocky point), Sonora, Mexico (28°43.564'N, - 112°36.799'W), 24 m depth, in situ temperature 19 °C, 01 November 1999, collector Carlos Sánchez; NMNH-1638562: dry, San Esteban Island (northwest rocky point), Sonora, Mexico (28°43.564'N, - 112°36.799'W), 24 m depth, in situ temperature 19 °C, 03 November 1999, collector Carlos Sánchez; NMNH-1638563: dry, San Pedro Nolasco Island (south rocky point), Sonora, Mexico (27°57.094'N, - 111°22.001'W), 30 m depth, 20 October 1999, collector Carlos Sánchez.

Type locality.

San Esteban Island is part of the midriff islands at the upper Gulf of California, and is the 15th largest island in Mexico by area (40 km²), and has predominantly volcanic rocky reefs. San Esteban Island is a UNESCO "Islas del Golfo de California" Biosphere Reserve (Fig. 1 )

Holotype colony description.

A bright yellow colony with planar growth and lateral branching (Fig. 6A, B ). The colony is 15.3 cm high and 115 cm wide. The colony has a 9 mm diameter holdfast attached to a rock of small size (14 mm × 11 mm) of biogenic origin from which emerges the main stem of 15 mm length and 2 mm diameter. The stem has longitudinal grooves. From the stem arise two main branches: one of 35 mm length and 2 mm diameter and the other of 117 mm length and 2 mm diameter. From these branches arise multiple secondary laterally growing branches. The terminal branches measure 20-30 mm long, 1.5 mm diameter, and have sharp points (Fig. 6B ). The polyp mounds are oval of 1 mm length and 0.5 mm width. Mounds are slightly evident with no elevation and are arranged irregularly or in rows on each side of all branches but not the stem.

Holotype sclerites.

The dominant type of sclerites is capstans of 0.06 mm length and 0.03 mm width (Fig. 7C ). There are abundant long spindles up to 0.11 mm long and 0.02 mm thick, which may or may not be slightly curved at the tips (Fig. 7A, B ). Crosses are unusual, of 0.06 mm × 0.06 mm diameter (not shown). Anthocodial sclerites are mostly small yellow rods of up to 0.05 mm length and 0.01 mm width, these anthocodial sclerites have smooth edges and blunt tips (Fig. 6D ). Long rods are also present, but in considerably low proportion.

Morphological variations.

Leptogorgia enrici sp. nov. has arborescent and planar forms of colony growth. The planar colony is the more common morphotype. Leptogorgia enrici sp. nov. has four solid colony colorations: yellow (Figs 6A, B , 8E ), orange (Fig. 6C ), purple, and white (Fig. 8F, G ) plus a rare bicolor colony (yellow with purple rings around the calices). The sclerites of the coenenchyme always have the same coloration as the colony.

Diagnosis.

The purple chromotype of Leptogorgia enrici sp. nov. is morphologically similar to the thin and planar morphotype of Leptogorgia rigida ; however, both species differ completely in the form of their sclerites. The coenenchyme sclerites of L. rigida consist mainly of robust capstans with short waists, double heads and spheres (absent in L. enrici sp. nov.), while the sclerites of L. enrici sp. nov. are mainly thin capstans and long and spindle sclerites; spindles are absent in L. rigida . These two species are distributed in different habitats: L. rigida in shallow areas (<10 m depth) attached to rocky reefs, typically inhabiting areas with strong currents or wave action and even in the cracks of rocks, while L. enrici sp. nov. is found in rocky reefs, sandy or pebble beds at depths usually <20 m depth. The morphology of L. enrici sp. nov. is similar in the type of branching and colony color to Leptogorgia chilensis (Verrill, 1868) and Leptogorgia flexilis (Verrill, 1868). However, these three species are distinct because L. enrici sp. nov. has colonies with planar growth and four solid chromotypes (yellow, orange, purple and white) and has many long spindles. Leptogorgia chilensis and L. flexilis show arborescent growth typically with branches very close to each other. Each species has a single colony chromotype ( L. chilensis is orange and L. flexilis is red) and spindle sclerites are present in low proportions, with blunt tips rather than the long spindles with pointed tips observed in L. enrici sp. nov. The long and acute spindles in L. enrici sp. nov., are only comparable in size to the spindles of Leptogorgia alba and Leptogorgia manabiensis Soler-Hurtado, Megina, Machordom & López-González, 2017 ( Soler-Hurtado et al. 2017b). However, these long spindles are the dominant type in L. alba and L. manabiensis , they are broad with acute ends and crowded tubercles. The dominant type of sclerites of L. enrici sp. nov. are capstans, the spindles are thin with blunt tips and with sparse tubercles. The anthocodial rods of L. alba and L. manabiensis are flat, long and have scalloped margins; while the anthocodial rods of L. enrici sp. nov. are mostly short with lobed margins and blunt tips.

Habitat and distribution.

Leptogorgia enrici sp. nov. is endemic to the Gulf of California (Cortez Province according to the biogeographic regions of Brusca and Wallerstein 1979 and Hasting 2000). Leptogorgia enrici sp. nov.'s highest densities are concentrated at the northern Gulf of California (northern Cortez sub-province) (Fig. 1 ), associated with the lowest winter sea surface temperature (SST, 15 °C), the widest annual range of SST (15-30 °C), and high marine productivity ( Ulate et al. 2016). Leptogorgia enrici sp. nov. inhabits substrates of rocky reefs, or pebbly and shell seafloor habitats surrounded by sand, in shallow waters (5-40 m depth), but most frequently between 20-40 m. Leptogorgia enrici sp. nov. may also be distributed in deeper waters.

Leptogorgia enrici sp. nov. occurs in low densities scattered on the reefs (<1 colony 100 m2) and never clustered in several colonies. Marine ecological censuses carried out during 2009, 2010 and 2018 showed L. enrici sp. nov. is distributed at the Mid-Rift Archipelago of the Gulf of California ( Ángel de la Guarda, Partida, Salsipuedes, Las Ánimas, San Lorenzo, San Esteban, San Pedro Mártir, Tortuga and San Marcos) and at the coast of Baja California peninsula (Los Choros). Leptogorgia enrici sp. nov. has been collected with scuba at 40 m in the central and southern Gulf of California (Isla Danzante and Isla Cerralvo). Leptogorgia enrici sp. nov. shares its habitat with Muricea spp., Muricea plantaginea (Valenciennes, 1846), Muricea austera Verrill, 1869, Muricea fruticosa Verrill, 1869, Eugorgia aurantiaca (Horn, 1861), Psammogorgia teres Verrill, 1868, and Heterogorgia papillosa Verrill, 1870.

Etymology.

Leptogorgia enrici sp. nov. is named in honor of Dr. Enric Sala, a National Geographic Explorer-in-Residence actively engaged in the exploration, research, and science communication to advance ocean conservation. Enric Sala is a passionate enthusiast of marine life and the conservation of Mexican seas who actively collaborates to generate marine biodiversity knowledge. He founded and leads the National Geographic’s Pristine Seas project that has conducted 30 expeditions in the world, creating 22 no-take large marine reserve (~5 million km2 of no-fishing zones).

Figures

Figure 6. Leptogorgia enrici sp. nov. A holotype NMNH- 1638560 B close up of terminal twig C orange chromotype colony D anthocodial and coenenchymal sclerites.

Figure 7. Leptogorgia enrici sp. nov., Scanning Electron Microscopy images of coenenchymal sclerites from the holotype NMNH- 1638560 A acute spindles B dull spindles C capstans.

Figure 8. Three new species of sea fans, colonies in situ, underwater images A Leptogorgia iridis sp. nov., San Juanito Island, Piedra El Morro, Islas Marias Archipelago, 10 m depth, 23 November 2010, a deep purple colony, at the base a small red wine colony of Leptogorgia ena B Leptogorgia iridis sp. nov., polyps close up C Leptogorgia martirensis sp. nov., Cueva Refugio, San Pedro Martir Island, Sonora, 2 - 3 m depth, 16 July 2010 into the cave several small colonies D Leptogorgia martirensis sp. nov., colony close up E Leptogorgia enrici sp. nov., Los Choros, BC, 25 m depth, 10 July 2009, two yellow colonies, a large colony of Eugorgia multifida in the background F Leptogorgia enrici sp. nov., El Bajo Sur, Cerralvo Island, BCS, 30 m depth, 23 June 2006, white colony G Leptogorgia enrici sp. nov., polyps close up. Photographs by Carlos Sanchez.

Figure l. Map of the Gulf of California and Mexican Pacific showing collection localities of the three new species of Leptogorgia.