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Terrazoanthus sinnigeri , sp. n.
Figures 4View Figure 4, 5, 6, 9, Tables 1, 2, 3
Etymology. This species is named for Dr. Frederic Sinniger, who has greatly helped spur the recent phylogenetic reexamination of zoanthid taxonomy. Noun in the genitive case.
Material examined. Type locality: Ecuador, Galapagos: Marchena I., Roca Espejo, 0.3125°N 90.4012°W.
Holotype: MHNG-INVE-67498. Colony divided into three pieces, on rocks of approximately 2.5 × 2.5 cm, 2.5 × 1.0 cm, and 2.0 × 1.5 cm, with heights of approximately 1.0 cm. Total of approximately 40 polyps connected by stolons. Polyps approximately 1.5–2.0 mm in diameter, and approximately 1.0–2.0 mm in height from coenenchyme. Polyps and coenenchyme encrusted with relatively large pieces of sand clearly visible to the naked eye, tissue of polyps and coenenchyme light brown/ grey in color. In situ, colony was on bottom of rock. Collected from Roca Espejo, Marchena I., Galapagos, Ecuador, at 9.1 m, collected by JDR, FL, and BR, March 3, 2007. Preserved in 99.5% ethanol.
Paratypes (all from Galapagos, Ecuador):
Paratype 1. Specimen number CMNH-ZG 05886. Glynn’s Reef, Darwin I., at 13 m, collected by FL and AC, March 7, 2007.
Paratype 2. Specimen number USNM 1134067. Glynn’s Reef, Darwin I., at 10 m, collected by JDR, FL, CH, March 7, 2007.
Other material (all from Galapagos, Ecuador):
MISE 464, Gardner, Floreana I., 27 m, collected by JDR and AC, March 13, 2007 ; MISE 471, Devil’s Crown, Floreana I., 7 m, collected by JDR and AC, March 13, 2007 ; MISE 418, Punta Espejo, Marchena I., 7 m, collected by JDR, FL, CH ,
Figure 5. Maximum likelihood ( ML) trees of a mitochondrial 16S ribosomal DNA, and b cytochrome
oxidase subunit I ( COI) sequences for zoanthid specimens. Values at branches represent ML probabilities
(>50%). Monophylies with more than 95% Bayesian posterior probabilities are shown by thick branches.
Sequences for new species in this study in larger font; sequences newly obtained in this study and new
taxa described in this study in bold. Sequences/species names from previous studies in regular font. For
specimen information see Table 1.
Figure 6. Maximum likelihood ( ML) tree of internal transcribed spacer of ribosomal DNA (ITS-rDNA) for Terrazoanthus specimen sequences. Values at branches represent ML probabilities (>50%). Monophylies with more than 95% Bayesian posterior probabilities are shown by thick branches. For specimen information see Table 1.
March 3, 2007; MISE 02-09, Entrance, Genovesa I., at 9 m, collected by CH, May 13, 2002 ; MISE 03-560, Punta Espego, Marchena I., 7 m, collected by CH, November 12, 2003 ; MISE 434, Glynn’s Reef , Darwin I., 13 m, collected by AC and FL, March 7, 2007 ; MISE 442, Don Ferdi , Bainbridge Rocks, 25 m, collected by AC, March 9, 2007 ; MISE 445, North Seymour I., 15 m, collected by MV, March 10, 2007 .
Sequences: See Table 1.
Description. Size: Polyps are approximately 2–8 mm in diameter when open, and rarely more than 10 mm in height. Colonies small, consisting of one polyp (unitary) to less than 50 polyps.
Morphology: Terrazoanthus sinnigeri has dull brown, white, or clear oral disks and the outer surface of polyps is heavily encrusted with large particles, with polyps clear of the stolon. Stolons are also heavily encrusted, and approximately the width of polyp diameters. T. sinnigeri has 30 to 36 tentacles that are almost as long or sometimes longer as the diameter of the expanded oral disk ( Figure 4View Figure 4). Tentacles often much more transparent than oral disks (when colored).
Cnidae: Basitrichs and microbasic p-mastigophores (often difficult to distinguish from each other), holotrichs (large, medium), spirocysts ( Table 2, Figure 9).
Differential diagnosis. In the Galápagos, Terrazoanthus sinnigeri differs from Parazoanthus darwini and Antipathozoanthus hickmani by substrate preference (rock as opposed to sponges and anthipatharians, respectively), as well as from Terrazoanthus onoi sp. n. (above) by both color (brown, white or transparent as opposed to bright red) and microhabitat (under rocks and rubble as opposed to exposed rock surfaces). In addition, T. sinnigeri is smaller (oral disk diameter and polyp height) than congener T. onoi . T. sinnigeri colonies are stoloniferous and generally much smaller than colonies of T. onoi ( Table 3). Terrazoanthus sinnigeri can be further distinguished from T. onoi by the presence of many types of nematocysts in the pharynx, unlike T. onoi , which only commonly possesses basitrichs and microbasic p-mastigophores with rare mediumsized holotrichs in the pharynx ( Table 2). Terrazoanthus sinnigeri also has small holot- richs, while T. onoi does not ( Table 2). Encrustations on the scapus of T. sinngeri are generally much larger than on T. onoi (compare Figures 3View Figure 3 and 4View Figure 4).
Similar to Terrazoanthus sinnigeri , there have been reports of other small zoanthids inhabiting cryptic habitats under coral rubble and rock from the Galápagos, Singapore and Japan (J.D. Reimer, T. Fujii, personal observation), but these zoanthids are clearly different in DNA sequence from all known Hydrozoanthidae and Parazoanthidae , and will be described elsewhere. Morphologically, these undescribed zoanthids look very similar to T. sinnigeri , but are often unitary (not colonial), are encrusted with very large pieces of sand, have very little coloring (usually lacking any color asides from around the oral opening) and have fewer tentacles (<26, usually 20–22; data not shown) than T. sinnigeri .
Habitat and distribution. Specimens located at depths of 7 to over 27 meters at Floreana, Marchena, Darwin, North Seymour Islands, and Bainbridge Rocks, with other potential specimens observed at other islands. It is likely that this species is widely distributed throughout the Galápagos, and its distribution may extend into deeper waters as it was often found at the lowest depth searched during collection dives. Generally found on the underside of rocks, rubble, or dead shells, often in small cracks or crevices.
Biology and associated species. Found under rocks and rubble, Terrazoanthus sinnigeri is often found nearby bryozoans and coralline algae, but appears to not be epizoic on any particular organism.
Notes. In Reimer et al. (2008b) it was originally thought that Terrazoanthus sinnigeri (specimens 02-09, 03-560) was a different, white morphotype of T. onoi (mentioned in the paper and Hickman (2008) as Parazoanthus sp. G3) based on COI and mt 16S rDNA sequence data, but given the species’ divergent morphologies, cnidae, and ecologies, as well as different ITS-rDNA sequences, we describe them as closely related but distinct species. It is likely that these two sibling species have recently diverged from one another.
Although speculative, it may be that Terrazoanthus sinnigeri ’s preferred habitat un- der rocks has resulted in its lack of bright pigmentation or occasional total lack of pigments compared to bright red T. onoi , which is found in areas more exposed to light, similar as to seen in subterranean invertebrates (e.g. Leys et al. 2003), and this should be investigated in the future.
Embrapa Agrobiology Diazothrophic Microbial Culture Collection
Amherst College, Beneski Museum of Natural History
Smithsonian Institution, National Museum of Natural History
Musee de Lectoure
University of Coimbra Botany Department
University of Montana Museum
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