Leptogorgia iridis, 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 iridis sp. nov. Figures 3 , 8A, B

Material examined.

Holotype. NMNH-1638551: dry María Magdalena Island (south west rocky point), Islas Marías Archipelago, Nayarit, Mexico (21°25.267'N, - 106°24.900'W), 10 m depth, 15 November 2010, collector Carlos Sánchez. Paratypes. NMNH-1638552: dry María Madre Island (southern rocky point), Islas Marías Archipelago, Nayarit, Mexico (21°32.391'N, - 106°31.877'W), 8 m depth, 18 November 2010, collector Carlos Sánchez. NMNH-1638553: dry María Madre Island (southwest rocky point, Islas Marías Archipelago, Nayarit, Mexico (21°32.391'N, - 106°31.877'W), 8 m depth, 18 November 2010, two colonies connected by single holdfast, collector Carlos Sánchez. NMNH-1638554: dry, María Madre Island (southwest rocky point), Islas Marías Archipelago, Nayarit, Mexico (21°25.267'N, - 106°24.900'W), 10 m depth, 15 November 2010, collector Carlos Sánchez. NMNH-1638555: dry colony from El Faro de Cabo Corrientes, Bahía Banderas, Jalisco, Mexico (20°24.553'N, - 105°41.708'W), 2013, collector Carlos Sánchez.

Type locality.

Islas Marías Archipelago is located in the southern region of the Gulf of California, Mexico (21°25.267'N, - 106°24.900'W) near the continental shelf-break about 158 km southwest of Mazatlán, Sinaloa and 106 km northwest of Bahía Banderas, Nayarit (Fig. 1 ).

Holotype colony description.

Colony shows lateral branching and planar growth of 7 cm height and 8.1 cm width. Holdfast is 5 mm diameter and arises the main steam 2.1 cm length and 2 mm diameter, subdividing into two main branches (Fig. 2A ). The longer branch grows up to 2.8 cm length and 2 mm diameter before dividing into secondary and further branches 1-2 mm in diameter. The smaller branches are 4 mm length and 1 mm diameter before subdividing and growing downward. The main stem shows three alternating and broken pinnula with a brownish nude axis of 0.5 mm diameter. Secondary and terminal twigs have blunt tips arising at 45° angles and of> 2 mm diameter. The entire colony is yellow and deep purple, forming longitudinal bicolor striped patterns along the branches from the base to the tips of the colony (Fig. 2A ). Polyp mounds are oval 1.0 × 0.5 mm, slightly raised by 1 mm with polyp rings, arranged in two rows along with the entire colony, except on the lower half of the stem.

Holotype sclerites.

Coenenchymal sclerites of Leptogorgia iridis sp. nov. holotype are mostly bright yellow or purple and few of them are bicolor or white (Fig. 2B ). Dominant sclerites are capstans (0.06 mm length and 0.04 mm width) (Fig. 3A ). Spindles are scarce (0.07 mm length and 0.03 mm width), slightly tuberculate, of white color with pale orange in the middle (Fig. 3B ). Crosses measure up to 0.05 mm length and 0.05 mm width. Anthocodial sclerites are long rods of <0.1 mm length and 0.02 mm width with acute ends and lobed margins (Fig. 3C ).

Morphological variations.

Leptogorgia iridis sp. nov. paratypes differ from the holotype in branch diameter and coloration. The morphotypes have a wide range of colorations due to the different proportion of sclerite colors and coenenchymal sclerite arrangement (Figs 2A-D , 8A, B ). There are four solid sclerite colorations: yellow, red, purple, and white or with a gradient of colorations among them, including bicolor chromotypes. A colony may have one or two sclerite colors, but their proportion and combination may create different patterns in the colony’s appearance. The holotype has yellow and purple sclerites with a longitudinal color arrangement giving the colony a bicolor (yellow and purple) appearance (Fig. 2A, B ). The paratype NMNH-1638553 also has a mixing of sclerites, one colony has the major sclerite proportion of purple compared to white, and the other colony has a major proportion of white compared to purple sclerites, and both colonies have a scrambled sclerite arrangement giving the colonies their coloration (Fig. 2C ). However, in several specimens, such as paratype NMNH-1638554, the colony and sclerite coloration is white (Fig. 2D ). Colony growth forms of L. iridis sp. nov. have relatively low variability. The only different morphotype, so far collected exclusively at Bahía Banderas, Jalisco, were colonies with similar coloration patterns to the holotype, but with relatively thicker branches (up to 4 mm diameter).

Diagnosis.

Purple and red Leptogorgia iridis sp. nov. have quite similar colony shapes. Both L. iridis sp. nov. chromotypes resemble the color of Leptogorgia obscura Bielschowsky, 1929 and Leptogorgia parva Bielschowsky, 1929. However, L. obscura has small anthocodial rods with blunt ends and L. parva has anthocodial rods with conspicuous lobed margins, which are absent in L. iridis sp. nov. Additionally, L. obscura and L. parva have only one known chromotype, and their terminal branches have acutely pointed ends. In contrast, L. iridis sp. nov., has long anthocodial rods with acute ends and no lobed margins, showing up to five solid colony chromotypes and terminal branches with blunt ends.

Habitat and distribution.

The distribution of Leptogorgia iridis sp. nov. covers part of the Central Tropical Mexican Pacific (Mexican Province in Brusca and Wallerstein 1979 and Hasting 2000) from Bahía Banderas, Jalisco to Islas Marías Archipelago Nayarit, Mexico (Fig. 2 ). Leptogorgia iridis sp. nov. grows on shallow rocky reefs <20 m depth. Purple colonies were mostly observed in shallow waters <5 m depth, the bicolor colonies mostly at 7-8 m depth, and yellow colonies mostly observed at 10-20 m depth. Leptogorgia iridis sp. nov. shares habitat with Leptogorgia ena Breedy, Abeytia & Guzman, 2012, Leptogorgia rigida Verrill, 1864, Leptogorgia alba (Duchassaing & Michelotti, 1864), Pacifigorgia arenata (Valenciennes, 1846), Pacifigorgia agassizii (Verrill, 1864), Pacifigorgia media (Verrill, 1864), Pacifigorgia stenobrochis (Valenciennes, 1846), Muricea austera Verrill, 1869, and Heterogorgia papillosa Verrill, 1870.

Etymology.

Leptogorgia iridis sp. nov. is named from the Latin word Leptogorgia iridis , which means “rainbow” due to the large number of chromotypes observed in the colonies. Large numbers of chromotypes are one of the main diagnostic characteristics of this novel tropical species.

Figures

Figure 2. Leptogorgia iridis sp. nov. A holotype NMNH- 1638551 B holotype anthocodial and coenenchymal sclerites C paratype NMNH- 1638553, two colonies with different color connected with a single holdfast D paratype NMNH- 1638554, monochromatic white chromotype.

Figure 3. Leptogorgia iridis sp. nov., Scanning Electron Microscopy images of coenenchymal sclerites from the holotype NMNH- 1638551 A capstans B spindle C anthocodial rod sclerites.

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.