Research Article |
Corresponding author: Stephen D. Cairns ( cairnss@si.edu ) Academic editor: Bert W. Hoeksema
© 2018 Stephen D. Cairns.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Cairns SD (2018) Deep-Water Octocorals (Cnidaria, Anthozoa) from the Galápagos and Cocos Islands. Part 1: Suborder Calcaxonia. ZooKeys 729: 1-46. https://doi.org/10.3897/zookeys.729.21779
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Thirteen species of deep-water calcaxonian octocorals belonging to the families Primnoidae, Chrysogorgiidae, and Isididae collected from off the Galápagos and Cocos Islands are described and figured. Seven of these species are described as new; nine of the 13 are not known outside the Galápagos region. Of the four species occurring elsewhere, two also occur in the eastern Pacific, one off Hawaii, and one from off Antarctica. A key to the 22 Indo-Pacific species of Callogorgia is provided to help distinguish those species.
Octocorals, Galápagos, Cocos Islands, Calcaxonia , Callogorgia
Early in my career (1986) I was privileged to participate in a deep-sea submersible expedition to the Galápagos and Cocos Islands, which was sponsored by SeaPharm, Inc. and HBOI (
Although the 1986 Johnson-Sea-Link expedition was the first submersible expedition to sample the deep waters off the Galápagos, it was not the first to collect deep-water invertebrates from this region. As early as 1888 the Albatross had made 13 deep-water stations (Alb 2806 to 2819) off these islands, 14 more stations again in 1891 (Alb 3400–3413), and another 10 stations (Alb 4636–4646) in 1904, all these specimens being deposited at the NMNH. The Johnson-Sea-Link also made additional collections in the Galápagos in 1995 (JSL-I-3900 to 3985) and in 1998 (JSL-II-3084 to 3113). More recently the E/V Nautilus has made deep-water collections in July 2015. Deep-water octocorals from all of these cruises were examined to form a basis for this report.
Thirteen deep-water octocoral species are reported herein, i.e., those that belong to the suborder Calcaxonia: Primnoidae, Chrysogorgiidae, and Isididae. Approximately an equal number of deep-water octocorals belonging to the families Alcyoniidae, Acanthogorgiidae, Plexauridae and the order Pennatulacea have also been collected from these islands and will be reported in later parts. Of these thirteen species, seven are described as new, four have range extensions, and only two had been previously reported from the Galápagos by
As explained in the Introduction, this study is based on all the deep-water calcaxonian octocoral specimens collected by the Albatross and John-Sea-Link I and II, which are deposited at the
The methodology concerning sclerite preparation for SEM can be found in
The following abbreviations are used in the text:
Museums / institutions
HBOI Harbor Branch Oceanographic Institute, Ft. Pierce, Florida
Vessels
Alb USFWS Albatross
GS R/V Gilliss
JSL-IJohnson-Sea-Link I submersible (HBOI)
JSL-IIJohnson-Sea-Link II submersible (HBOI)
NA E/V Nautilus
Other terms
L:W ratio of length to width of a polyp or sclerite
SEM scanning electron microscope
Callozostron
Callozostron mirabile Wright and Studer, 1889, by monotypy.
Colonies unbranched, sparsely dichotomously branched, or pinnately branched. Polyps arranged in whorls, the bases of adjacent polyps sometimes fused. Polyps covered by eight longitudinal rows of body wall scales, which completely cover the polyp. At least four and up to 24 marginal and submarginal scales bear elongate slender apical spines; marginal scales do not fold over operculars. Coenenchymal scales similar to those of body wall, arranged in one layer. All scales thin, with a smooth pouter face and tuberculate inner face.
Antarctic, Subantarctic, Antipodes, New Zealand, Clarion-Clipperton Fracture Zone, Galápagos, 744–4235 m deep.
A discussion and key to the six species in this genus are given by
Callozostron
carlottae
Nautilus NA064-77-01-A, 1 branch, 1.82° C,
Four specimens (?syntypes) are included in the original description. Their deposition is unknown.
Antarctica (between 60–90°E), 3397 m depth (Gauss German South Polar Expedition of 1901–1903).
Galápagos: east of Fernandina, 3381 m depth. Elsewhere: Antarctica, 3397 m depth.
Although only one incomplete colony is available (Figure
The body wall scales (Figures
Despite the long distance between the Antarctic type locality and the Galápagos, this specimen is identified as C. carlottae, but it does differ in several points from the original description. The Galápagos specimen has larger polyps, and thus larger opercular and marginal spines, those of the Antarctic syntypes being only 0.6 mm and 0.8 mm in length, respectively. And the Antarctic syntypes have eight or nine polyps per whorl, whereas the Galápagos specimen has only six or seven. Otherwise, the two specimens are remarkably similar, the Galápagos specimen even showing the dimorphic-sized submarginal spines (
This is the first report of this species subsequent to its original description, and was collected at virtually the same depth.
Callogorgia
Caligorgia
Gorgonia verticillata Pallas, 1766, by monotypy.
Colonies uniplanar, pinnately or dichotomously branched. Polyps cylindrical to clavate, arranged in whorls of up to 12, all polyps facing upward. Polyps covered with eight longitudinal rows of body wall scales, the number of scales per row decreasing from ab- to adaxial polyp side. Body wall scales granular, smooth, pitted, or covered with tall ridges (cristate). Inner side of opercular scales convex, covered with a multiply serrate keel.
Indo-Pacific, Atlantic, 37–2472 m deep.
The identification of the species of Callogorgia has been greatly facilitated by the availability of previously published dichotomous keys. The structure and characters used for the first published key were chosen by
1 | Branching typically pinnate | 2 |
– | Branching dichotomous or quasi-dichotomous | 13 |
2 | Branches strictly opposite | C. formosa (Kükenthal, 1907) |
– | Branches alternate | 3 |
3 | Scales in outer lateral body wall rows well developed, i.e., having the same or only slightly fewer than those in abaxial row | 4 |
– | Scales in outer lateral body wall rows sharply reduced in number, i.e., usually less than half the number as that in abaxial row | 6 |
4 | Coenenchymal scales elongate and not thick; outer surface of abaxial body wall scales on distal half of polyp highly ridged | *C. galapagensis sp. n. |
– | Coenenchymal scales irregular in shape and quite thick (tessellate); outer surface of body wall scales granular or pitted (not ridged) | 5 |
5 | Seven to nine scales in abaxial body wall scale rows; body walls scales pitted; polyps 1.4–1.8 mm in length | C. sertosa (Wright and Studer, 1889) |
– | Nine to eleven scales in abaxial body wall scale rows; body wall scales granular; polyps 1.0–1.2 mm in length | C. tessellata Cairns, 2016 |
6 | Operculum low and inconspicuous | C. pennacea (Versluys, 1906) |
– | Operculum tall and prominent | 7 |
7 | Abaxial opercular scales with two to four apical points | *C. weltneri (Versluys, 1906) |
– | Abaxial opercular scales with a single point | 8 |
8 | Eight or more scales in each abaxial body wall row | 9 |
– | Six to eight scales in each abaxial body wall row | 11 |
9 | Apex of opercular scales prolonged into a rod-like (cylindrical) point | *C. ramosa (Kükenthal and Gorzawsky, 1908) |
– | Apex of opercular scales not prolonged in a cylindrical point | 10 |
10 | Eight to ten scales in abaxial body wall scale rows | *C. flabellum (Ehrenberg, 1834) |
– | Eleven to thirteen scales in abaxial body wall scale rows | *C. gilberti (Nutting, 1908) |
11 | Polyps about 2 mm tall | *C. robusta (Versluys, 1906) |
– | Polyps 1.0–1.8 mm tall | 12 |
12 | Coenenchymal scales elongate; inner lateral and adaxial body wall scales present; eastern Pacific | C. kinoshitai (Kükenthal, 1913) |
– | Coenenchymal scales polygonal; inner lateral and adaxial body wall scales absent; South Pacific | C. joubini (Versluys, 1906) |
13 | Scales in outer lateral body wall rows well developed, i.e., having the same or only slightly fewer than those in abaxial row | 14 |
– | Scales in outer lateral body wall rows sharply reduced in number, i.e., usually less than half the number as that in abaxial row | 15 |
14 | Five or six scales in each abaxial body wall row | C. dichotoma Cairns, 2016 |
– | Ten scales in each abaxial body wall row | C. versluysi (Thomson, 1905) |
– | Twelve or 13 scales in each abaxial body wall row | C. imperialis Cairns, in press |
15 | Three scales in each outer lateral body wall row | 16 |
– | One or two scales in each outer lateral body wall row | 17 |
16 | Four polyps per whorl | C. elegans (Gray, 1870) |
– | Two or three polyps per whorl | C. indica (Thomson and Henderson, 1906) |
17 | Five scales in each abaxial body wall row | 18 |
– | Seven scales in each abaxial body wall row | 19 |
18 | Two or three polyps per whorl; eight to nine whorls per cm branch length; body wall scales with low marginal ridges | C. minuta (Versluys, 1906) |
– | Three or four polyps per whorl; 9–11 whorls per cm branch length; body wall scales with distal margins strongly reflexed, exposing high crest-like ridges on inner face | C. chariessa Bayer, 1982 |
19 | Two or three polyps per whorl; seven to eight whorls per cm branch length | C. similis (Versluys, 1906) |
– | Four to six polyps per whorl; nine to ten whorls per cm branch length | 20 |
20 | Abaxial body wall scales with strong marginal ridges | *C. affinis (Versluys, 1906) |
– | Abaxial body wall scales with only weak marginal ridges | C. modesta (Studer, 1878) |
Types. Holotype: JSL-I-1933, large colony and SEM stubs 2295–2297, 2308–2311,
JSL-I-1933: 0°17.072'S, 91°04.208'W (off northwest tip of Fernandina, Galápagos), 663–788 m deep.
Galápagos: Tagus Cove between Isabela and Fernandina, north of Española, 308–633 m deep; Cocos Island, 628–656 m deep.
Colonies are uniplanar and taller than broad, the holotype (Figure
There are eight longitudinal rows of body wall scales, decreasing in number from ab- to adaxial polyp side, the body wall sclerite formula being: 10–12:10–12:4–5:2. The distal five or six pairs of abaxial scales (Figure
Colonies of various species. a Narella enigma, holotype,
Polyps and sclerites of Callozostron carlottae from NA64-77-01-A. a lateral stereo view of two polyp whorls b–d lateral stereo views of three polyps showing spinose marginal and submarginal scales and non-spinose proximal body wall scales e opercular scales f lower, non-spinose body wall scales g wide base of marginal scales h spinose submarginal scales i marginal scales j coenenchymal scales.
Callogorgia galapagensis belongs to a group of eight species that have highly cristate abaxial body wall scales, the other seven species listed in
Polyps and sclerites of Callogorgia galapagensis from the holotype, JSL-I-1933,
Named for the type locality of the species.
Calligorgia
sertosa
Calligorgia
kinoshitae
Callogorgia
kinoshitae
Alb-3406, 1 colony and SEM stubs 2300–2302,
As defined by the syntype series, the type-locality extends from northern Baja California (latitude 30°30'30"N) to just north of San Diego (latitude 33°02'15"N), and includes the bathymetric range of 219–2469 m.
Galápagos: between Santa Cruz and Marchena, 605–1008 m deep. Elsewhere: northern Baja California to Monterey Bay (new records), California, 219–2469 m deep.
Colonies are uniplanar and taller than wide, the largest Galápagos specimen (Alb-3406) a broken colony only 18 cm in height, but the largest syntype measuring up to 26 cm in height. Branching is alternate pinnate (sympodial and geniculate, Figure
There are eight longitudinal rows of body wall scales, decreasing in number from ab- to adaxial polyp side, the body wall sclerite formula being: 6–8:1–2:1–2:1–2. The marginal and submarginal abaxial body wall scales (Figure
Polyps and sclerites of Callogorgia kinoshitai (aAlb-4357,
Although this species was originally identified as C. sertosa by
This species was clearly named after Kumao Kinoshita, and thus the name is herein changed to reflect a masculine ending.
Calyptrophora
Calyptrophora japonica Gray, 1866, by monotypy.
Colonies uniplanar to slightly bushy (lyrate, dichotomous, polychotomous, biplanar) or unbranched. Polyps arranged in whorls, the polyps facing either upward or downward. Polyps consist of two annular sclerite rings, each composed of two inseparably fused scales; a pair of crescent-shaped infrabasals also present. Articular ridge present between basal and buccal body wall scale. Distal margins of body wall scales often spinose, toothed, or lobate. Operculum composed of eight scales; keels usually present on inner face of opercular scales. Coenenchymal scales elongate and flat, sometimes quite thick (as plates). Small curved tentacular platelets often present.
Tropical and temperate latitudes of Atlantic, Pacific, and Indian Oceans, 227–3531 m deep.
Including the new species described herein, the genus contains 23 species, making it the fifth most species-rich genus within the primnoids.
Calyptrophora
agassizii
JSL-I-1922, 1 colony,
Syntypes: several branches from which 99% of the polyps are detached, MCZ 4815, and SEM 1357–1358,
Alb-3404: 1°03'S, 89°28'W (south of San Cristóbal, Galápagos), 704 m depth.
Galápagos: west of Isabela, off Marchena and San Cristóbal, 509–1545 m deep.
The colony is uniplanar, equally and dichotomously branched; the largest colony (JSL-I-3108, Figure
The fused basal scale (Figures
Polyps and sclerites of Calyptrophora agassizii from the holotype, Alb-3404 , MCZ 4815. a lateral stereo view of a polyp b–c adaxial stereo views of a polyp d basal scales e articulating ridge of inner basal scale f longitudinal ridging on a basal spine g two buccal scales h opercular scales i infrabasal scales j coenenchymal scales.
Comparisons. Only four of the 23 species of Calyptrophora have polyps oriented in the downward direction (
Remarks. Several monographers have redescribed this species, but apparently based only on the type material. This is the first subsequent report of the species based on new material. The latitude reported by
Types. Holotype: colony and SEM stubs 2334–2337, JSL-I-3930,
JSL-I-3930: 0°29.755'S, 90°13.98'W (northeast coast of Santa Cruz, Galápagos), 450 m depth.
Galápagos: off Santa Cruz, Santiago, and Marchena, 445–509 m depth.
The colony is uniplanar, equally and sparsely dichotomously branched, some end branches up to 12 cm in length. The holotype (Figure
The fused basal scale (Figures
Polyps and sclerites of Calyptrophora reedi from the holotype,
Only four species in the genus have downward oriented polyps, the so called wyvillei-complex sensu
Named in honor of John Reed (HBOI), who participated in the JSL-I Galápagos expedition of 1986, during which this species was collected.
Narella
Stachyodes
Primnoa regularis Duchassaing and Michelotti, 1860, by monotypy.
(from
All ocean basins except Arctic, 128–4594 m deep.
Previously (
Stachyodes
ambigua
Narella
ambigua
Branch fragments and detached polyps from Alb-3404, MCZ 79048, and
As mentioned in the account of Calyptrophora agassizii, about 65% of the type lot (branches and detached polyps) of that species consisted of Narella ambigua. Narella ambigua was collected at the previous station (Alb-3403) to that of C. agassizii (Alb-3404), approximately 20 km to the northeast and bathymetrically 2 m shallower, both stations from off the southern coast of San Cristóbal. The Narella specimens were separated from the type lot of C. agassizii in 2008 and cataloged as MCZ 79048. Since the type of S. ambigua could not be found at the MCZ in 2008, the specimens cataloged as MCZ 79048 may serve as representative topotypic specimens, and may in fact be type material. A fragment of this colony is also deposited at the
Alb-3403: 0°58'30"S, 89°17'W (south of San Cristóbal, Galápagos), 702 m depth.
Galápagos: off Santiago, Santa Cruz, and San Cristóbal), 702–741 m deep. Elsewhere: off Panama, 1463 m depth (herein, GS-21).
The colony is uniplanar, and dichotomously (laterally) and sparsely branched (Figure
The basal scales (Figure
Polyps and sclerites of Narella ambigua from Alb-2818,
Narella ambigua is easily distinguished from the somewhat similar Paracalyptrophora enigma by its long terminal branches, polychaete commensalism that causes highly modified basal scales, fewer polyp whorls per cm, non-toothed basal scales, lack of an articular ridge, and granular (not ridged) coenenchymal scales.
Although discussed by several authors through the years (see synonymy), this is the first subsequent report of this species since its original description.
Calyptrophora kerberti Versluys, 1906, by subsequent designation (
Colonies dichotomously branched in one plane, sometimes in a lyrate pattern and sometimes as two parallel fans. Polyps arranged in whorls of up to eight, all polyps pointed downward. Each polyp covered with two (rarely three) unfused pairs of body wall scales. Articluar ridge present between basal and buccal (or medial) body wall scales. Distal margins of buccal scales smooth or spinose. A pair of infrabasal scales often present. Coenenchymal scales elongate, granular, and sometimes ridged.
Southwestern Pacific Ocean, Galapagos, Japan, Hawaii, North Atlantic, 150–1480 m deep.
The genus diagnosis is herein expanded to accommodate a species having three pairs of body wall scales, otherwise similar to the genus Narella. The character placing it in Paracalyptrophora is its possession of an articular ridge, which is found in this genus as well as Calyptrophora, and is considered more significant than the number of body wall scales.
Types. Holotype: colony and SEM stubs 2338–2342, JSL-I-1915,
1°17.2'S, 89°48.7'W (northwest of Española, Galápagos), 653 m depth.
Known only from northwest of Española, Galápagos, 547–653 m deep.
The colony is uniplanar, equally and dichotomously branched, the largest colony (the holotype, Figure
The basal scales (Figures
Polyps and sclerites of Narella enigma from the holotype, JSL-I-1915,
Superficially this species resembles the genus Narella, in that it has three pairs of body wall scales, but the distal inner surface of the basal scales have an articular ridge, which is more consistent with the genus Paracalyptrophora, P. enigma being the only species in the genus with three pairs of body wall scales.
Named “enigma” (Latin for inexplicable) because it is the only species in the genus to have three (not two) pairs of body wall scales.
Plumarella
Gorgonia penna Lamarck, 1815, by subsequent designation (
Colonies usually uniplanar and alternately pinnately branched, dichotomously branched, or bottlebrush in shape. Polyps arranged in alternate biserial fashion (nominate subgenus), crowded on all sides (subgenus Dicholaphis), paired (subgenus Faxiella), or arranged in whorls (subgenus Verticillata). Each polyp covered by eight rows of body wall scales, the adaxial scales usually somewhat smaller. Distal edges of marginal body wall scales do not overlap much of opercular scales. Inner surface of opercular scales may be smooth or ridged, but not keeled, except in subgenus Faxiella.
Indo-Pacific, western Atlantic, Subantarctic, 10–3181 m deep.
There are 37 species in the genus arranged in four subgenera, most listed in
Amphilaphis
abietina
Thouarella (Amphilaphis) abietina
Not Thouarella abietina
Plumarella (Faxiella) abietina
Alb-2818, 1 colony in very poor condition (most of its polyps detached) and SEM stubs 2343–2346,
Holotype: Alb-3399, MCZ 4802.
1°07'N, 81°04'W (lower continental slope off northwestern Ecuador, at same latitude as Galápagos Islands but about 860 km to the east), 3181 m depth.
Galápagos: east of Santa Cruz and off Roca Redonda, 717–808 m deep. Elsewhere: off Ecuador, 3181 m depth.
The colony is uniplanar to slightly bushy, the Galápagos specimen (Alb-2818, Figure
The body wall scales (Figure
This is the deepest of the 37 known species in the genus. Only one other species occurs in this subgenus, P. (F.) delicatula (Thompson and Rennet, 1931), known only from the New Zealand region at 650–2743 m depth (
The specimens reported herein are only the second report of the species. It fits the re-description of the holotype given by
Stenella
Stenella (Parastenella)
Parastenella
Stenella doderleini Wright and Studer, 1889, by subsequent designation (
Colonies uniplanar to slightly bushy; branching lateral and somewhat irregular. Polyps stand perpendicular to branch, arranged independently or in pairs or whorls of up to four. Eight marginal scales present, offset in position from opercular scales; marginal, and sometimes submarginal, scales fluted; nematocyst pads present on distal inner surface of fluted marginals. Body wall scales arranged in four to eight longitudinal rows. Operculum well developed, the distal inner surface of operculars prominently keeled. Coenenchymal scales flat to highly concave, sometimes ridged. Pinnular rodlets sometimes present.
Cosmopolitan, except for eastern Atlantic, the Arctic, and off continental Antarctica, 475–3470 m depth.
Including the new species described herein, there are eight species known in this distinctive genus. Accounts of Parastenella species are found in
Types. Holotype: colony and SEM stubs 2303–2305, JSL-I-1922,
0°23.68'N, 90°26.341'W (off northeastern Marchena), 475–578 m deep.
Galápagos: off Marchena, Santiago, and Isabela, 446–578 m deep.
The colony is uniplanar, the largest colony (the holotype, Figure
The body wall scales (Figure
Polyps and sclerites of Parastenella pomponiae from the holotype, JSL-I-1922,
Parastenella pomponiae is morphologically most similar to P. ramosa (Studer, 1894), known from the eastern Pacific from the Gulf of Alaska to Panama, but differs from that species in having eight (not five) rows of body wall scales, concave (not flat) coenenchymal scales, wider fluted marginal scales, and in lacking submarginal fluted body wall scales.
Named in honor of Shirley Pomponi (formerly of HBOI), who participated in the JSL-I expedition of 1986, during which this species was collected.
Chrysogorgia
Dasygorgia
Chrysogorgia desbonni Duchassaing and Michelotti, 1864, by monotypy.
Branching from main branch sympodial in an ascending spiral, clockwise (R) or counterclockwise (L), usually following a repeated geometric branching formula, producing a bottlebrush colony, or dichotomous in one or more parallel planes. Branchlets repeatedly dichotomously branched, resulting in short terminal segments. Polyps large in relation to branchlets, standing perpendicular to branchlets and usually well separated. Sclerites consist of rods and scales. Axis with a brilliant metallic luster, usually golden or yellow in color, and thus referred to as the golden corals.
Cosmopolitan, including off Antarctica (
In order to manage the relatively large number of species in the genus, now standing at 70,
The four species groups of Chrysogorgia determined by a combination of body wall and tentacular sclerite type.
Body Wall Rods | Body Wall Scales | |
---|---|---|
Tentacular Rods | Group A: 38 species: Indo-West Pacific, Atlantic; 100–3114 m. 2/5R, 1/4L, 3/8L, 1/3R, 2/5L, 1/3L, dichotomous, irregular, pinnate | Group B: 13 species: Indo-West Pacific, western Atlantic; 250–2271 m. 1/4R, 1/5R, 1/6R, 1/7R, 1/7R, 2/5R, biflabellate |
Tentacular Scales | Group D: 1 species: off Brazil, 1300 m. dichotomous | Group C: 18 species: Indo-West Pacific, North Atlantic, Antarctic; 204–3860 m. 1/3L, 1/4L, 2/5L, 1/4R, flabellate |
Chrysogorgia
curvata
Chrysogorgia
scintillans
JSL-I-1927, 1 colony and SEM stubs 2327–2331,
The holotype is deposited at the
Alb-4153: between Kauai and Moku Manu, 1758–1937 m deep.
Galápagos: between Isabela and Santiago; Cocos Island, 628–768 m deep. Elsewhere: Hawaiian Islands, 1758–1937 m deep.
The colony is biplanar (perhaps multiplanar), the largest colony examined (JSL-I-1927, Figure
The body wall scales (Figure
Chrysogorgia scintillans belongs to “Group C” sensu
Types. Holotype: colony and SEM stubs 2316–2319, 2350–2316, JSL-I-1915,
1°17'12"S, 89°48'42"W (north of Española, Galápagos), 650–662 m deep.
Throughout Galápagos from Roca Redondo to Española, 560–816 m deep.
The colony is bottlebrush in shape (Figure
The body wall sclerites (Figure
Having rods in its body wall and tentacles places C. midas in Chrysogorgia Group A, the largest of the four groups of Chrysogorgia, consisting of 38 species (Table
Named “midas” (from the Greek Midas, the mythical king at whose touch everything turned to gold) in allusion to the golden luster of the branch axis, characteristic of the genus.
Types. Holotype: colony and SEM stubs 2320–2322, JSL-I-1929,
0°14'40"N, 91°36'32"W (off Roca Redonda, Galápagos), 806 m depth.
Galápagos: Roca Redonda, west of Santa Cruz, 717–806 m deep; Cocos Islands, 614–785 m deep.
The colony is bottlebrush in shape (Figure
The upper body wall sclerites (Figure
Polyps and sclerites of Chrysogorgia laevorsa, JSL-I-1929,
Having rods in its body wall and tentacles places C. laevorsa in Chrysogorgia Group A, the largest of the four groups of Chrysogorgia, having 38 species. Chrysogorgia laevorsa is the only species in this group to have a 2/5L branching formula, whereas 14 species in this group have a 2/5 R formula (Figure
Named laevorsa (from the Latin laevorsus, meaning “towards the left”) in allusion to the direction of the branching formula (2/5L).
Isidella
Isis elongata Esper, 1788, by monotypy.
Colonies sparsely branched, dichotomously or trichotomously from nodes, resulting in a uniplanar colony; internodes long and hollow. Polyps non-retractile, cylindrical, armed with stout needles placed longitudinally in body wall. Spiny pharyngeal rodlets present.
Northeast Atlantic (including Mediterranean), New England Seamounts, eastern Pacific from California to Alaska, Hawaii, Galápagos, 400–2593 m deep (
Including the species described below, there are currently six species in the genus, three of which occur in the Pacific. The genus was most recently keyed and discussed by
Using one or two mitochondrial genes and six species (most of them undescribed),
Isidella
sp.
Types. Holotype: colony and SEM stubs 2355–2358, JSL-I-1942,
5°34.6'N, 87°04.25'W (off Cocos Island), 606–628 m deep.
Known only form the type locality.
The colony is uniplanar, the largest specimen (the holotype, Figure
The polyps are uniserially placed (Figure
Polyps and sclerites of Isidella tenuis, holotype, JSL-I-1929,
Isidella tenuis differs from I. trichotoma Bayer, 1990 (Hawaii, 1920 m) in having dichotomous branching, much smaller coenenchymal and body wall sclerites, and differently shaped pharyngeal sclerites. Isidella tenuis differs from I. tentaculatum Etnoyer, 2008 (California to Alaska, 720–1050 m) in having needle-shaped body wall scales, differently shaped pharyngeal scales, smaller polyps, uniserial polyps, and blunt-tipped body wall sclerites.
Named “tenuis” (Latin for thin) in reference to the slender polyps of the species.
I am grateful to John Reed for the gift of specimens collected on the three JSL expeditions to the Galápagos, and to Les Watling and Nicole Raineault (Ocean Exploration Trust) for facilitating the loan of three specimens collected by the E/V Nautilus. Molly Ryan executed the drawing of Figure
Station | Latitude / Longitude | Depth (m) | Date | |
---|---|---|---|---|
JSL-I | ||||
1912 | 0°21.877'S, 90°15.747'W | 806 | Nov 14 1986 | |
1915 | 1°17.2'S, 89°48.7'W | 650 | Nov 15 1986 | |
1916 | 1°18.715'S, 89°48.809'W | 545–562 | Nov 16 1986 | |
1922 | 0°23.683'N, 90°26.341'W | 475–578 | Nov 19 1986 | |
1927 | 0°10.50'S, 90°53.25'W | 708–782 | Nov 21 1986 | |
1929 | 0°14.675'N, 91°36.526'W | 804 | Nov 23 1986 | |
1930 | 0°03.057'S, 91°33.927'W | 333–478 | Nov 23 1986 | |
1931 | 0°10.303'S, 91°24.675'W | 441–528 | Nov 24 1986 | |
1933 | 0°17.072'S, 91°40.208'W | 663–788 | Nov 25 1986 | |
1934 | 0°15.16'S, 91°27.93'W | 252–308 | Nov 25 1986 | |
1935 | 0°29.737'S, 91°23.806'W | 391–488 | Nov 26 1986 | |
1938 | 5°24.49'N, 87°09.83'W | 614–785 | Nov 30 1986 | |
1942 | 5°34.60'N, 87°04.25'W | 606–628 | Dec 2 1986 | |
3902 | 1°18.763'S, 89°48.82'W | 554 | Oct 17 1995 | |
3907 | 0°20.517'N, 90°23.788'W | 530–576 | Oct 19 1995 | |
3912 | 0°08.581'N, 91°23.708'W | 489 | Oct 21 1995 | |
3925 | 0°17.100'S, 91°05.046'W | 768 | Oct 28 1995 | |
3930 | 0°29.749'S, 90°13.981'W | 450 | Oct 30 1995 | |
JSL-II | ||||
3108 | 0°24.00'N, 90°26.5'W | 1545 | Jul 21 1998 | |
USFWS Albatross | ||||
2818 | 0°29'S, 89°54'30"W | 717 | Apr 15 1888 | |
3399 | 1°07'00"N, 81°04'W | 3182 | Mar 24 1891 | |
3403 | 0°58'30"S, 89°17'W | 700 | Mar 28 1891 | |
3404 | 1°03'S, 89°28'W | 704 | Mar 28 1891 | |
3406 | 0°16'S, 90°21'30"W | 1008 | Apr 3 1891 | |
3410 | 0°19'N, 90°34'W | 805 | Apr 3 1891 | |
4153 | 23°05'N, 161°52'W | 1760–1837 | Aug 5 1902 | |
4357 | 32°N, 117°W | 245–284 | Mar 15 1904 | |
4530 | 36°45'N, 121°55'W | 1381–1752 | May 27 1904 | |
4537 | 36°45'N, 121°55'W | 1575–1942 | May 31 1904 | |
R/V Gilliss | ||||
21 | 7°11'N, 79°16'W | 1463 | Jan 18 1972 | |
E/V Nautilus | ||||
NA64–77–01 | 0°23.40'S, 91°52.98'W | 3381 | Jul 3 2015 | |
NA64–125–01 | 0°22.60'S, 90°40.05'W | 446 | Jul 6 2015 | |
NA64–126–01 | 0°22.59'S, 90°49.06'W | 445 | Jul 6 2015 |