Studies On Western Atlantic Octocorallia (Coelenterata : Anthozoa). Part 2: The Genus Callogorgia Gray, 1858

28 Pages·2002·10.1 MB·English

by  S D Cairns

PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
115(4):840-867. 2002.
Studies on western Atlantic Octocorallia (Coelenterata: Anthozoa).
Part 2: The genus Callogorgia Gray, 1858
Stephen D. Cairns and Frederick M. Bayer
Department of Systematic Biology (Invertebrate Zoology), National Museum of Natural History,
Smithsonian Institution, P. O. Box 37012, Washington, D.C. 20013-7012, U.S.A.,
e-mail: [email protected]
—
Abstract. Of the three species of Callogorgia now recognized in the west-
ern Atlantic, one that had been misidentified as Callogorgia verticillata, an
eastern Atlantic and Mediterranean species, is now established as a new species
in its own right, comprised oftwo subspecies. A second, C. gracilis, originally
reported from Guadeloupe, is redescribed on the basis of type material and
A C
additional specimens. third species, linguimaris, is described as new.
Records ofall three species preserved in the collection ofthe National Museum
of Natural History, Washington, D.C, are reported, and the species are illus-
trated by scanning electron micrography.
Species of the genus Callogorgia, and Material and Methods
many other primnoid genera, have some of
the most conspicuous polyps and largest The prominent polyps of Callogorgia,
sclerites ofall octocorals. Their polyp scler- which are armor-plated with large, scale-
ites (scales) are delicately and sometimes like sclerites, are vulnerable to damage
ornately sculpted, and arranged in such a from the moment of collection onwards.
definite pattern and number that the total Abrasion in the trawl or dredge inflicts
number of polyp sclerites is fairly constant some damage, and specimens are obtained
per species and often numbers less than 50. in a broken condition, usually with many
Species occur exclusively in deep water polyps rubbed off. Handling by the scien-
(82-2472 m) and are found worldwide in tific crew under the pressures of sea-going
tropical and warm temperate regions. There operations results in a second stage ofdam-
are about 26 species known, but only three age incurred during initial preservation in
are currently recognized in the western At- bulk on shipboard. Further attrition occurs
lantic, although several more species re- in the laboratory during sorting and rebot-
main to be described from this region, as tling procedures. Even in their final con-
implied by Verrill (unpub.) and personal tainers, most primnoids remain prone to
observations. But, in her report on the oc- damage with even the most careful han-
tocorals ofthe western Atlantic, Deichmann dling during scientific study. Each time a
(1936) recognized only two species of Cal- specimen is removed from its container
logorgia (there spelled Caligorgia): C. more polyps inevitably are broken loose,
gracilis (Milne Edwards & Haime) and C. falling as a calcareous rain to the bottom of
verticillata (Pallas). The former species is the container It is therefore imperative that
redescribed based on the type and addition- not only curatorial personnel charged with
al specimens; the latter is reidentified as the maintenance of gorgonian collections, but
new species C americana; and a third spe- also the researchers carrying out scientific
cies, C. linguimaris, is described from the studies, should handle primnoid specimens
Tongue of the Ocean, Bahamas. as little and as carefully as possible.
VOLUME 115, NUMBER 4 841
Designation of polyp scales used here ida and Surinam reveal the morphological
follows the system employed by Versluys diversity that led Verrill (unpub.) to distin-
(1906) as modified by Bayer (1982). Syn- guish five species of Callogorgia. Two ma-
onymies for all species are purported to be jor types are, indeed, recognizable, one in
complete. which the distal abaxial scales ofthe polyps
T—he following abbreviatio—ns are used: are sculptured externally with strong, sharp,
CI RA'^ Columbus Iselin; G RA^ Gerda; radially arranged crests, and one in which
MCZ—
JSL-I—R/V Johnson-Sea-Link /; the scales are externally sculptured more or
Museum ofCom—parativeZoology, Harvar—d, less distinctly with simple tubercles but
Cambridge; O M/V, R—fV Oregon; P never with high crests (although a series of
RA' Pillsbury; RMNH Nationaal Natu- thin radial ridges occurs along the distal in-
urhistorisch Museum, Leiden, The Nether- ner margin ofthe scales where they overlap
lands (formerly Rijks—museum van Natuur- the scale above).
lijke Historic); SEM Scanning Electron Closer study shows that within these two
Microscopy (in the context of material ex- general types morphological variations oc-
amined sections, the specific stub numb—er cur suggesting the existence of as many as
in the Bayer sequence ofSEM stubs); SB six species. These two types, which possi-
TCWC—
MA^, R/V Silver Bay; Texas Co- bly represent species-groups, are also rec-
A&M
operative Wildlife Collection, Texas ognizable among the Pacific species ofCal-
—
USNM C
University; United States National logorgia. To the former belong flabellum
Museum (now known as the National Mu- (Ehrenberg), C. cristata Aurivillius, C. ro-
C
seum of Natural History, Smithsonian), busta Versluys, C. weltneri Versluys, gil-
Washington, D.C. berti Nutting, and C. kinoshitae KUkenthal;
C
to the latter belong affinis Versluys, C.
& C
Subclass Octocorallia sertosa Wright Studer, minuta Ver-
Order Alcyonacea sluys, C. similis Versluys, and C. chariessa
Suborder Calcaxonia Bayer. The status of these species remains
Family Primnoidae Gray, 1858 to be clarified when sufficient material to
Genus Callogorgia Gray, 1858 evaluate variation becomes available for
— study.
Diagnosis. Pinnately branched prim- The characters available for discrimina-
noids with polyps facing upward, always in tion ofspecies remain essentially thoseused
whorls; polyps curved inward toward axis, by Versluys (1906), whose exemplary treat-
with only abaxial rows ofbody scales com- ment of the Primnoidae of the Siboga Ex-
plete, those of adaxial rows always reduced pedition placed the classification of the
in number or absent and leaving most of family on a firm scientific basis. These are
adaxial body wall naked, those ofinner-lat- colonial in form and manner of branching,
eral and outer-lateral rows also reduced in size and number of polyps in the whorls,
number or absent; distalmost scale in each spacing of whorls along the branches,
body-scale row specialized as an opercular sculpturing and number ofscales in the lon-
scale different in shape from the subjacent gitudinal rows of sclerites on the body of
marginal scale; abaxial and lateral opercular the polyps, and the form and sculpturing of
scales articulating with respective marginal the coenenchymal sclerites.
scales near the distal edge so marginals can- Unfortunately, these characters, which
not fold inward over operculars. Type-Spe- served reasonably well for the discrimina-
cies: Gorgonia verticillata Pallas, 1766, by tion of species when relatively few speci-
monotypy. — mens were involved, become unreliable
Remarks. Examination of over 100 lots when many specimens are available for
from the waters between the Straits ofFlor- study.
842 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 1. A, Callogorgia americana americana, syntype branch from P-889, USNM 52883, X 0.38; B, C.
americana delta, syntype branch from 0-365I, USNM 52903, X 0.53; C, C. lingiiimaris. syntypes from C/-15,
USNM 94580, X 0.36; D, C. gracilis, holotype, MNHNP, X 0.34.
VOLUME 115, NUMBER 4 843
1. Branching. In the western Atlantic, al- young polyps ordinarily occur at branch
ternate pinnate branching is the rule, but the tips. As the branchlet elongates, the number
group of species corresponding to Deich- of polyps per whorl is augmented proxi-
mann's C gracilis have closer, moreregular mally by the addition of new polyps be-
pinnate branching than do those corre- tween the original ones until the maximal
sponding to her C. verticillata, in which the number is attained. As the branchlets grow,
lateral branchlets are farther apart and the new whorls of polyps arise between pre-
primary axis bends slightly away from each existing whorls when space between them
lateral branchlet that is produced, thus as- becomes sufficient. As young individuals
suming a weakly zigzag (quasisympodial) comprising new whorls are usually of sim-
course. ilar size, it is apparent that they originate
2. Length oflateral branchlets. Colonies more or less simultaneously, but new
of the ""gracilis group" tend to have short- whorls with polyps of disparate size have
er, stiffer branchlets than do those of the been observed.
"verticillata group," but even among col- The ability to repair damage and regen-
onies with very similar polyps, some may erate lost polyps is well developed. The
have long, flexible branchlets while others common occurrence of regenerating polyps
have short, stiff ones. It is clear that water indicates occasional predation, perhaps by
currents have a significant influence on fishes, which might nip off individual pol-
growth form in other gorgonians, but in- yps. Pleurotomariid gastropods have been
sufficient data are available for assessment observed browsing upon colonies of Cal-
of environmental effects on the form of logorgia, confirmed by recovery ofsclerites
Callogorgia colonies. from gut contents (M. G. Harasewych, pers.
3. Number ofpolyps per whorl. On the comm.). Such browsing might also account
lateral branchlets, polyps are always ar- for loss of polyps. Detached branchlets that
ranged with great regularity in opposite become entangled among branchlets lower
pairs or in whorls ofthree or more; on larg- in the colony may be cemented in place at
er branches, this arrangement may be dis- points of contact. It is not known how such
rupted by the irregularinsertion ofnew pol- branchlets might be broken loose in the rel-
yps and the loss or resorption of old ones. atively quiet, deep waters inhabited by Cal-
Some species have a strong tendency to- logorgia, but the agency of some predator
ward arrangement in pairs but this is by no must be suspected.
means constant and whorls of three or four 4. Number ofwhorlsper centimeter. Al-
polyps usually appear on the proximal part though a component ofmost descriptions of
of the branchlets. Other species rarely if species, this character was not used by Kii-
ever produce polyps in pairs, and the num- kenthal (1919, 1924) in his keys to the spe-
ber per whorl tends to increase basally by cies of Callogorgia. Although subject to
the insertion of young polyps between ma- variation as pointed out by Thomson &
ture ones when the diameter of the branch- Rennet (1931), it is nevertheless a useful
let becomes large enough to accommodate clue in the identification of specimens.
them. 5. Number and arrangement of polyp
Addition of polyps on actively growing scales. The polypal sclerites in genera of
branchlets occurs both terminally and prox- primnoids having polyps straight or little
imally. New individuals do not necessarily inclined or bent toward the axis of the
originate simultaneously at the growing tip branches are arranged along the body in
of branchlets, as branch tips with a single eight longitudinal rows. The number of
young polyp have been observed. However, scales in the adaxial rows has more or less
in species with polyps typically arranged in been reduced owing to shortening ofthe ad-
whorls, as in Callogorgia, two or three axial side but all eight rows nevertheless
844 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
persist at the distalmost part of the polyps in the ornamentation ofthe outer surface of
even if greatly reduced elsewhere on the both coenenchymal and polyp sclerites. The
body. In most genera the 8 sclerites sur- fact that immature polyps may have dis-
rounding the tentacles fold together over tinctly sculptured body scales while fully
the mouth and tentacles as a protective grown polyps of the same colony have
operculum when the polyp is contracted. In smooth scales indicates that this character
genera such as Callogorgia having polyps may be influenced by unknown external
that bend inward toward the axis for pro- conditions during development of the indi-
tection, the side of the body facing the axis vidual polyps.
(i.e., adaxial) may have few or no sclerites The most pronounced variants would
other than the operculars as there is no certainly have been treated as distinct spe-
room for them when the polyp is shortened cies in the past, and might still be so treated
during contraction. The abaxial surface, save for the degree of intergradation re-
however, remains vulnerable to attack, re- vealed by abundant material from a wide
sulting in the strong development of pro- geographical area. Unfortunately, characters
tective, platelike sclerites. Those ofthe two that in one species may be stable and reli-
abaxial rows are the largest and comprise able, in another may be variable and not
from 3 to 11 curved scales in each row, diagnostic. This circumstance makes the
extending from the operculars to the base construction of keys difficult and identifi-
of the polyp. The development of scales in cation of specimens by their use an uncer-
the outer-lateral and inner-lateral row on tain matter at best. Only by side-by-side
each side of the body necessary to achieve comparison of all specimens, and evalua-
complete coverage is influenced by the tion in relation to depth and locality, has it
amount ofcurvature when the body is com- been possible to reach the tentative conclu-
pletely bent inward, and by the width ofthe sions here presented to the taxonomic prob-
abaxial scales. lem posed by this collection. In fact, it re-
The outer-lateral rows usually have at mains an open question whether the Cal-
least one scale, the "marginal" scale (des- logorgia gracilis "complex" consists of
ignated outer-lateral 1), on each side, but in two, three, four, or only one species.
the middle part ofthe body the outer-lateral
tract on each side may be covered more or Key to the western Atlantic species and
less completely by a wide lateral extension subspecies of Callogorgia
of some of the adaxial scales ("fliigelartige
Ausbreitung" of Versluys, 1906:81). The 1. oSuctaelressoufrfcaoceensecnuclhpytumreedanwditpholywpesakwittho
larger outer-lateral 1 is, and the more abax- moderately strong radiating, sometimes
ials that are widened toward the axis, the anastomosing, ridges. Outer-lateral
fewer outer-lateral scales are needed to cov- scale rows usually represented by 1
er the sides of the polyp. marginal scale, sometimes absent; in-
The inner-lateral tracts may have one ner-lateral scales always absent; adaxi-
C
scale (inner-lateral 1) on each side but als usually absent gracilis
these, too, may be suppressed by enlarge- r. Scales of coenenchyme with outer sur-
ment of outer-lateral 1. In colonies whose face nearly smooth or sculptured with
polyps normally have an inner-lateral 1 on more or less distinct granules radiating
from center; distal, abaxial, and outer-
each side, that scale can be replaced either
lateral body scales externally sculptured
by the broadly expanded basal lobe of the
with finely serrated crests most conspic-
inner-lateral opercular scale, or by a lateral uous on marginal scales, gradually de-
extension of the abaxial 2. creasing in prominence proximally until
6. External sculpturing or ornamenta- scales of basal half of body are smooth
tion ofsclerites. Wide variation occurs also or only faintly ridged. Outer-lateral
VOLUME 115, NUMBER 4 845
rows with 1-4 scales; inner-lateral rows 371-372; 192—4:270 (part: records from
with 1-2; adaxial rows usually with 1 West Indies). Deichmann, 1936:159-
scale 2 161, pi. 25, figs. 5-9, pi. 26, fig. 6.—
2. P3-o7l;yp4s-5dis(toirncstolymectliamveatse,6)inwhwohrolrslsinof1 CaBlalyoegro,rg1i9a54:v2e8rt1ic(iUlsltaetda)..—Bayer, 1956:
cm of branchlet; outer-lateral rows of
F220, figs. 158, 4; 159, 2; 1958:388 (in
body sclerites always represented by
2^ scales ... 3 (C. americana sensu lato) part: O-590, O-1048); 1961:297, figs.
2'. Polyps cylindrical, arranged in opposite 96a-d (in part: not records off Surinam
pairs (i.e., whorls of 2) distally, some- and Cuba).
times increasing to whorls of 3 proxi-
mally; 4 whorls in 1 cm; outer-lateral Material examined/types (all specimens
row of body scales with 1-2 scales listed below are considered to be syn-
Callogorgia linguimaris,. .n.. sp. types).—STRAITS OF FLORIDA: off Se-
3. Cristate sculpture of abaxial and outer- bastian Inlet, Florida: 27°59'N, 79°20'W,
lateral scales strong and complicated, 586-567 m, 7^-197, 11 Aug 1964, 10 pin-
crests of distalmost 3-4 scales stout, nate branches, the largest 42 cm tall,
high, often divided into lobes and cov- USNM 52890 (SEM 373); 2 pieces ofmain
ering most or all of exposed surface of stem and detached branches, USNM 52882
scale (SEM 334).
Callogorgia americana americana, n. subsp.
Off Indian River Inlet, Florida: 27°30'N,
3'. Cristate sculpture of abaxial and outer-
lateral body scales more delicate and 79°22'W, 579-569 m, G-663, 17 Jul 1965,
less complicated, consisting of several 5 large branches, the largest over50 cmtall,
USNM
thin, narrow lobes situated around free 52880.
margin ofscales, leaving remaining sur- Off Settlement Point, Grand Bahama:
face nearly or quite smooth 27°09'N, 79°18'W, 604 m, G-386, 19 Sep
.... Callogorgia americana delta, n. subsp. 1964, piece of main stem broken off at
holdfast, and 3 pieces of stem with lateral
Callogorgia americana, new species branchlets, all possibly part of one colony,
Figs. lA, 2-4 USNM 52879 (SEM 457).
Not Primnoaflabellum Pallas, 1766:134. Off Ft. Lauderdale, Florida: 26°04'N,
Not Gorgonia verticillata Pallas, 1766:177. 79°24'W, 549-512 m, G-715, 2 Aug 1965,
— USNM
Not Callogorgia verticillata. Gray, 1858: 1 lateral branchlet, 52884.
286. — 11 km off Carysfort Reef Lighthouse,
Primnoaflabellum. Duchassaing & Mich- Key Largo, Florida, 204 m, coll. FM. Bayer
elotti, 1860:17. — et al., MA'^ Megalopa, University ofMiami,
Primnoa verticillaris. Pourtales, 1868: 8 Jul 1950, 2 incomplete lateral branchlets,
USNM
130. 51954.
Calligorgia americana Verrill, MS, cap- OffSand Key, Pourtales Plateau, Florida,
tions of pi. 27, figs, la-e; pi. 82, figs. 4, depth unknown. State University of Iowa
4a, 4b [unpublished original text]. (Nutting) Bahamas Expedition, Station 29,
Calligorgia aspera Verrill, MS, caption of 4 large branches, USNM 91851.
pi. 25, fig. 1 [unpublished original text]. SSE of Key Largo, Florida: 24°54'N,
Calligorgia asperula Verrill, MS, captions 80°15'N, 219-212 m, G-794, 19 Aug 1966,
USNM
of pi. 27, figs. 2, 2a, 2b [unpublished 9 branches from a large colony,
original text; labeled as C aspera on bot- 52881 (SEM 214, 215, 365).
tom of plate]. E of Sombrero Key, Florida: 24°24'N,
Caligorgia americana Kiikenthal, 1919:372 80°41'N, 296-289 m, G-840, 11 Jul 1967,
[nomen nudum]. — 3 small pinnate branches, USNM 52887
Caligorgia verticillata. Kiikenthal, 1919: (SEM 332, 463).
846 PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OFWASHINGTON
Off The Samboes, S of Boca Chita Key, OffSt. Lucia: 14°05.2'N, 60°50.3'W, 311
Florida, 200 m, coll. John B. Henderson, m, P-891, 7 Jul 1969, 4 large branches,
Yacht Eolis, 1916, 4 fragments, USNM USNM 52885 (SEM 212).
44131. OffSt. Lucia: 14°04.4'N, 60°50.8'W 402
Off Key West, Florida: 24°20'N, m, P-889; 7 Jul 1869, 3 pieces of stem, 3
82°04'W, 220 m, SB-2A21 29 Oct 1960, 6 pinnate branches and several smaller frag-
,
incomplete lateral branchlets, USNM ments, USNM 52883 (SEM 337, 458, 465);
RMNH
52889. 1 stem, Coel. 31169.
Off Key West, Florida, 183-220 m, coll. Caribbean Sea N of Peninsula de Paria,
John B. Henderson, Yacht Eolis, 1916, 3 Venezuela: 11°30'N, 62°29'W, 329 m,
USNM
incomplete lateral branchlets, 0-2772, 15 Apr 1960, 2 large branches,
44161. USNM 58393 (SEM 358, 359, 397).
Off Key West, Florida: 24°17'05"N, Caribbean Sea offIsla Tortuga, Venezue-
81°58'25"W, 242 m, Fish Hawk sta. 7280, la: iriO'N, 65°07'W, 420 m, O-4480, 21
14 Feb 1902, several pinnate branches and Oct 1963; 1 branch, USNM 52888 (SEM
USNM
fragments, 44160. 332).
Off Sand Key, south of Key West, Flor- Specimens reported by Deichmann
ida, 200 m, coll. John B. Henderson, Yacht (1936): Blake stations 208, 216, 233, 269,
Eolis, 1916, 1 poorly preserved specimen, 281. —
USNM 44159 (SEM 369, 376). Diagnosis. Callogorgia with crestlike
Off Dry Tortugas, Florida: 24°11'N, radial sculpture on outer-lateral and distal-
83°21.5'W, 732 m, 5B-1196, 8 Jun 1959, 6 most 2—4 abaxial scales, strongest on mar-
USNM
broken branches, 51485. ginals and becoming progressively weaker
STRAITS OF YUCATAN: NE of Cape proximad; 7-11 body scales in abaxial
Catoche, Yucatan: 22°40.2'N, 86°36.6'W, rows, 2-4 in outer-lateral rows, 1-2 in in-
377 m, O-590, 12 Jun 1952, 1 main branch ner-lateral rows, and usually 1 in adaxial
and fragments of branches with lateral rows; 4-6 whorl—s in 1 cm of twig length.
branchlets, USNM 50850; 27 main branch- Description. The plumose, flabellate
es (dry) USNM 51298 (SEM 456). colonies reach 1 m or more in height,
NE of Cape Catoche, Yucatan: branched in an alternate pinnate manner.
22°41.9'N, 86°41.2'W, 411 m, 0-726, 11 Lateral branchlets vary in length from 50
Feb 1953, 1 specimen (dry), USNM 51299 to 150 mm in length, but commonly are 75—
(SEM 459). 100 mm long. The distance between
Bahia de Campeche, Campeche Bank branchlets along one side of the stem (i.e.,
WNW
ofThe Triangles: 2ri7'N, 91°18'W, internodal length X2) ranges from 7 to 15
37 m, O-1048, 13 May 1954, 3 branches mm; rarely, 2 branches originate from one
badly decalcified by formalin, USNM node on the same side of the stem. New
50527. lateral branchlets originate only near the
Old Bahama Channel off Cay Sal: apex of the main stems, not between pre-
22°59'N, 79°17'W, 458 m, 0-1343, 16 Jul existing branchlets. At the origin of each
1955, 4 pinnate branches, USNM 50185 branchlet, the main stem bends a few de-
(SEM 370, 371). grees away from the branchlet, so the stem
ANTILLES: Mona Passage: 18°16'N, follows a slightly zigzag course. This is
67°16.5'W, 421 m, 0-2652, 6 Oct 1959, 2 most conspicuous distally, becoming less
USNM
branches, 51578. obvious on the lower parts of the colony
Lesser Antilles off Guadeloupe: where it is obscured by secondary thick-
16°33.2'N, 61°36.8'W 366 m, P-944, 17 Jul ening of the primary axes.
1969, 1 apical branch with 9 branchlets, Polyps in contraction (Fig. 2) are bent
USNM
52868. strongly inward toward the axis, clavate.
VOLUME 115, NUMBER 4 847
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848 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OFWASHINGTON
Fig. 2. Callogorgia americanaamericana fromP-889. USNM 52883: three stereo views ofthe anangement
ofsclerites covering the polyps and stem, scale bar applies to all three views (X 46).
VOLUME 115, NUMBER 4 849
mm
about 1.3-1.5 tall, arranged in regular ward the branch, such that the proximal 3
whorls of 3-7, 6 being the most common or 4 abaxials are smooth, bearing only
number. Four to six (usually 5) whorls oc- small aligned granules or low ridges. The
cur in 1 cm of axial length. Polyps persist broad outer-lateral scales also bear longi-
on the larger main branches and stems, but tudinal crests, but only on their abaxial por-
there the verticillate arrangement is usually tion (adjacent to the abaxials), the remain-
irregular. der of these scales bearing a low granula-
All 8 longitudinal rows of body scales tion. The broad inner-lateral scales have a
are represented, 7-11 scales in the abaxial granular external sculpture. The adaxial
rows, 2—4 in the outer-lateral rows, 1 or 2 scales are square and quite small, located
in the inner-lateral rows, but the adaxial directly beneath the adaxial opercularscales
rows consist of only one, or sometimes 2, and often overlapped by the adaxial margin
small scales below the adaxial operculars. of the inner-lateral scales. Below the adax-
Rarely there are additional short rows of 1- ial scales the polyp is bare, devoid of scler-
3 outer-lateral scales adjacent to the most ites, allowing the polyp to fold inward.
proximal abaxials and thus separated from The operculum is well developed, the
the other outer-lateral scales that are adja- large abaxial and outer-lateral opercular
cent to the distal abaxials; however, when scales forming a prominent, bluntly conical
the polyp is strongly bent inward, these dis- covering over the infolded tentacles, the in-
junct sclerites come into contact. The ab- ner-lateral and adaxial operculars being
axial body scales are usually arranged in somewhat smaller. The opercular scales
pairs across the sagittal axis, but are some- (Fig. 3A-G) are triangular, sometimes with
times slightly offset, and occasionally a a longitudinal sagittal furrow or crease on
small extra scale is intercalated on only one the outer surface, which corresponds to a
side, making it difficult to accurately count keel on the inner surface. Several promi-
the number in a complete abaxial row. The nent, longitudinal ridges on the outer sur-
abaxial (outer) edges of the abaxial scales face radiate from the base, and the inner
abut each other or slightly overlap. The surface is covered with crowded, complex
most proximal 3 or 4 abaxials are quite tubercles. The tentacles contain small, ir-
wide and curved, almost entirely circling regularly sculptured rods.
the polyp. Toward the tip of the polyp the The coenenchymal sclerites (Fig. 3S) are
abaxial scales dramatically decrease in long (up to 0.7 mm), broad (0.10-0.18
width, becoming rectangular to square in mm), flattened rods, sometimes irregularly
shape at the polyp margin, the lateral region lobed or branched, with finely granular
of the polyp being covered with 2-4 broad sculpture on the exposed surface and close-
outer-lateral scales and 1 or 2 broad inner- ly set complex tubercles on the inner, to-
lateral scales. These additional short rows gether with some smaller scales with gran-
of scales produce the characteristic clavate ular or cristate external sculpture. In gen-
shape of the polyp. The distalmost 4 or 5 eral, the coenenchymal sclerites are only
pairs ofabaxial sclerites bearprominent (up one layer thi—ck.
mm C
to 0.1 in height), finely serrated crests Variation. Specimens of americana
radiating outward from near the middle of show much less variation than is observed
the tuberculate proximal border to the distal in C. gracilis. Although the cristate sculp-
margin, where they form strong dentations. ture of the distal abaxial and outer-lateral
These crests, which are longitudinally to body scales varies from rather coarse, as in
USNM
slightly obliquely oriented, are so tall that 52890 from the east coast of Flor-
USNM
they often obscure the boundary between ida, to rather fine, as in 52883 from
the abaxials and outer-lateral scales. The St. Lucia, most specimens fall somewhere
height of the crests gradually decreases to- between those extremes. This sculptural