Bijdragen lot de Dierkunde, 54 (2): 243-262—1984
Taxonomic characters in Caribbean Millepora species
(Hydrozoa, Coelenterata)
by
Walentina H. de Weerdt
Institute of Taxonomie Zoology, University of Amsterdam,
P. 0. Box 20125, 1000 HC Amsterdam, The Netherlands
Summary size of the and gastropores dactylopores, pore
density and structure of the ampullae, have In order to find characters in Millepora species with a
been studied in the or were higher diagnostic value than the growth form (on which hardly past con- sidered useless because species delimitation is hitherto based) a comparison is of high intraspecific made of the surface structure, microstructure of the variation 1948 1949 (Boschma, a & b, a, 1950,
skeleton, structure of the ampullae coverings, size of the 1964; Martinez Estalella, 1982). In some Atlan- and and in gastropores dactylopores, pore density tic the form of the species, however, growth cor- specimens of the four species occurring in the Caribbean allum is which often im- M. M. and variable, region: Millepora alcicornis, complanata, squarrosa, extremely
identification. This M. striata. While most characters are of little taxonomic pedes a good variability
sizes and densities useful. The value, pore are surprisingly be the fact may partly explained by that
species are diagnosed and some biogeographical remarks various Millepora has a high adaptability to en- are given. vironmental circumstances, like depth, water
movement, current, and turbidity. Résumé In in a previous paper (De Weerdt, 1981), Afin de trouver dans les espèces de Millepora des caractères which I reviewed the taxonomie problems in de valeur caractè- diagnostique supérieure par rapport aux Millepora, the need to search for other characters res du habitus (sur lesquels la délimitation des espèces est is stressed. However, when it is attempted to jusqu’à présent fondée), on a effectué des comparaisons the of sur: les structures superficielles, les microstructures du distinguish species Millepora on a more
squelette, la structure des revêtements des ampullae, la sound base than the growth form, only few taille des des gastéropores et dactylopores, ainsi sur la que characters are available for taxonomie in- densité des dans des des pores, exemplaires quatre espèces Another vestigation. problem is the scarceness des Caraïbes: M. M. M. M. alcicornis, complanata, squarrosa, of type-specimens and the lack of ecological striata. La de ces caractères s’avèrent être de de plupart peu valeur la mais la taille la densité des data in museum collections. these im- pour taxonomie, et Despite pores se montrent remarquablement utiles. Des diagnoses perfections it seemed nevertheless worth while
fournies des formu- sont et remarques biogéographiques the results from of to present obtained a study lées les mentionnées. pour espèces morphological characters of a collection of
tropical Western Atlantic Millepora species.
INTRODUCTION This study is restricted to species occurring in
the Caribbean region, viz. Millepora alcicornis
Species delimitation in the hydrocoral Millepora Linnaeus, 1758; M. complanata Lamarck, 1816;
M. M. (Milleporidae, Capitata, Hydrozoa), with squarrosa Lamarck, 1816; and striata about Indo-Pacific & 1864. The latter eight and six Atlantic spe- Duchassaing Michelotti,
the form of Boschma cies, was hitherto based on growth species was synonymized by (1948a) the corallum and with M. it here geographical distribution squarrosa, but is regarded as a
valid in with (Boschma, 1948 a & b, 1961, 1962, 1966; Weis- species, accordance an unpublish-
ed of Boschma. bord, 1968; Roos, 1971; Stearn & Riding, 1973; manuscript
The taxonomie De Weerdt, 1981). Other characters, such as validity of the following 244 W. H. DE WEERDT - CARIBBEAN MILLEPORA
is examined: of the Goreau characters growth form cor- 1969; Mergner, 1969; Roos, 1971; &
allum, texture of the surface, microstructure of Goreau, 1973; Stearn & Riding, 1973; Colin,
De Martinez the skeleton, structure of the ampullae cover- 1978; Weerdt, 1981; Estalella,
ings, time of reproduction, size of the 1982). It will be explained here how this
and and of lead to identifica- gastropores dactylopores, density polymorphy can easily wrong
the tions, and which form be exhibited pores. growth may
the four Caribbean The species are diagnosed and some by Millepora species.
biogeographical remarks are given.
In Boschma's revision of Millepora (Boschma,
MATERIAL AND METHODS 1948 a), extensive descriptions of the growth
forms of the the species are given. Briefly, Most corals were collected by the author in the period from
till 1977 the Carib- forms of the Caribbean January 1976 January during a stay at growth species are, ac-
bean Marine Biological Institute Curaçao. (Carmabi), cording to his descriptions: Several localities off the coast of Curaçao and Bonaire, M. alcicornis: extremely variable, at the growing edge representing a wide variety of biotopes, were visited and divided into branches which as a rule are laterally com- all growth forms encountered between 0 and 50 m were but be less Some pressed may more or finger-like. colonies gathered. About 250 specimens were collected, and others of are decidedly delicately branched, are a Taxonomische very deposited at the Instituut voor Zoölogie, compact growth form. Zoölogisch Museum, Amsterdam (ZMA), the M. complanata: upstandingplates, growingout from a com- Netherlands.
mon basal part. from Additional specimens were borrowed the Rijks- M. thin with lateral squarrosa: upstanding plates, numerous Leiden the museum van Natuurlijke Historie, (RMNH), which each other united form expansions, among are to a Muséum National d'Histoire Naturelle, Paris (MNHN), more or less honeycombed complex. and the Hessisches Landesmuseum, Darmstadt, Ger- M. striata (Boschma, unpubl. ms.): "pronouncedly in the British Museum many. Specimens present (Natural branching in all directions". History), London (BMNH), were also studied.
During this work I received great help from some un- The growth forms of the other two Atlantic published manuscripts of the late Prof. Dr. H. Boschma,
which Prof. Dr. W. Vervoort known from the Brazilian were put at my disposal by species, only region,
(RMNH). are described as:
M. braziliensis: "erect cylindrical branches that at their tops
divide into smaller branches" (Boschma, 1961: 293). RESULTS M. nitida: "low rounded clumps, consisting of short, rapid-
ly forking, rounded or slightly compressed branches, VARIATION AND TAXONOMIC USEFULNESS OF
which are obtuse, rounded, or even davate at the ends" MORPHOLOGICAL CHARACTERS
[abbreviated after Verrill, 1868: 362. In Boschma's revi-
the sion 1948 this with Growth form of corallum (Boschma, a) species was synonymized
M. alcicornis. Later he considered it (Boschma, 1962) as a
to Boschma a & who According (1948 b), valid species, but he did not redescribe it.]
revised the genus Millepora after a period of
and different splitting lumping by authors From these descriptions it is easily, but er-
concluded thatM. is the (Duchassaing & Michelotti, 1864; Hickson, roneously, squarrosa on-
1898 the the form which a & b; Wood-Jones, 1907), growth ly species showing growth is
form of the corallum is the only character which sometimes called "honeycombed", sometimes
is sufficiently distinct in most species to warrant "boxwork" (terminology used by Stearn &
identification. reliable From recent studies on Riding, 1973; Colin, 1978; and De Weerdt,
Millepora and coral reefs in general it has, 1981). It is the growth form in which "upstand-
become that identificationof thin with lateral however, apparent ing plates, numerous expan-
the in the Atlantic Ocean still each other united form species occurring sions, are among to
remains very difficult, because of the high a more or less honeycombed complex"
of the three degree polymorphy expressed by species (Boschma, 1948 a: 19). However, of the
four Caribbean (Goreau, 1959; Weisbord, 1968; Mattraw, species may exhibit such a - 245 BIJDRAGEN TOT DE DIERKUNDE, 54 (2) 1984
able resist the growth form, viz. M. complanata, M. squarrosa strong masses, quite to high and M. striata. This mistake is other in the surf Corals with an among water energy zone.
form the other things demonstrated by Boschma's identifica- exclusively plate-like growth on tion of in the ZMA collection and and four specimens hand were rare at Curaçao Bonaire,
M. from and (ZMACoel. 8370, 8371, 8372, and 8373) as judging descriptions photographs
in the Carrión squarrosa (Boschma, 1948 a: 102), and one (Almy & Torres, 1963; Colin, 1978),
collection Even be restricted to RMNH (RMNH 16876). this phenomenon seems not to
Boschma identified them as M. these islands. though squar-
Boschma's rosa, he remarked that all specimens have a Using descriptions sensu stricto,
M. would be growth form intermediate between M. com- complanata turn out to a rare
and M. the basis whereas M. would be planata squarrosa. However, on species, squarrosa quite
The is M. of criteria discussed below, two of the specimens common. reverse, however, true:
of the in the ZMA collection belong to M. complanata complanata is one most common Millepora
(ZMA Coel. 8372, 8373), whereas the other two species in the Caribbean region, extremely
M. striata Coel. and main constituents specimens belong to (ZMA polymorphous one of the
the other 8370, 8371). of the recent reefs. M. squarrosa on
Another of this iden- hand is not example misleading very rare, probably polymorphous
criterion is and it does contribute the tification the following: in a previous not to high extent to
with of reefs reliable references of paper dealing Millepora (De Weerdt, building recent (cf.
1981), I classified the growth forms of Millepora this species, see Systematic descriptions).
Bonaire in encountered on Curaçao and seven categories: boxwork dwarf form, thick bladed boxwork, thin bladed boxwork, bladed, in- Comparing the three species which may have
differences crusting, coarse branching, and fine branching. a boxwork growth form, some slight
Boschma's the first Using descriptions strictly, are present, constant enough to justify some three would M. remarks them here. categories represent squarrosa, on the fourth M. complanata,, the incrusting form In full-grown colonies of M. squarrosa the
and the latter would remain unidentifiable, two general aspect of the growth form is more com-
M. alcicornis. Another could than in colonies of M. would be possibility pact full-grown com-
be viz. first record of The remain connected not excluded, a Caribbean planata. plates along
M. braziliensis. Corals consisting of thick, erect their whole length, whereas the plates in M.
divided show divide in their cylindrical branches, distally into complanata a tendency to top smaller Corals of the latter have looser branches, are regularly found at Playa parts. species a
Abao, Curaçao (ZMA Coel. 8127, 8133, 8166); aspect altogether, suggesting that M. complanata
with Boschma's faster than M. Exact data on they seem to agree completely grows squarrosa. diagnosis of M. braziliensis. However, only two this aspect are not available, so this remark re-
and viz. M. mains In III 1 the species occur on Curaçao Bonaire, speculative. plate fig. type- alcicornis both of M. and M. complanata, extremely specimen squarrosa (MNHN, no registra- polymorphous and quite often undistinguish- tion number) is shown. In plate II fig. 1 a large able, which will be discussed later. The corals colony of M. complanata (ZMA Coel. 8213) is agreeing with Boschma's description of M. figured. It is rather obvious that the specimen of braziliensis fall within the variation of M. M. consists of twisted of com- squarrosa plates a very
The of the of planata (they were compared with the specimens compact aspect. plates specimens
M. of M. braziliensis in the RMNH collection). complanata are much looser. Furthermore,
of the corals collected and the in the of M. Most on Curaçao plates type-specimen squarrosa
doubt M. divided in their remain Bonaire, no belonging to complanata, are not top parts; they show boxwork of massive whereas a growth form, consisting along the whole length, the
which interconnected into in the of M. show plates are heavily plates specimen complanata a 246 W. H. DE WEERDT - CARIBBEAN MILLEPORA
divide form lateral tendency to and to expan- becomes plate-like. Sometimes it is even dif-
sions in between the delicate their top parts. ficult to distinguish most
In colonies the differences in form of M. and the younger growth complanata more stouter
form in M. forms of M. alcicornis. are more conspicuous: squarrosa The growth form of this
young colonies are very stubby with smooth species may be diagnosed as follows:
whereas colonies of branches and rounded edges, young Millepora alcicornis : branching, the
M. consist of small but form complanata single plates or vary, they always upright structures;
boxwork with their branches constructions, sharp growing at top parts the are mostly
edges. (Compare plate III fig. 2 which laterally compressed.
of M. with the form of the four represents a young colony squarrosa Summarizing, growth
of M. Caribbean is plate II fig. 2, a young colony complanata.) Millepora species highly variable,
When M. and M. but within certain limits. it complanata squarrosa are However, can not
with the third which be used as the sole identification compared species may character,
have M. since three of the four exhibit a honeycombed growth form, striata, species may
small differences the following, are visible: in almost similar growth forms. The slight dif-
M. striata the of the divide in ferences in corals tendency plates to with the honeycombed aspect
their is The be subtle reliable identifica- top parts most strongly developed. may too to warrant
specimen belonging to M. striata ZMA Coel. tion. In combination with other characters, the
identified Boschma as M. form be iden- 8370, by squarrosa growth may a support to a good
(Boschma, 1948 a: 102, 2nd paragraph) is a tification.
of coral. The has very large piece greater part
but the consists died, top part of numerous Texture of the surface clusters of newly formed plate-like outgrowths
in all Plate IV 1 shows In the shows directions. fig. a some species surface constant
of M. striata. The looseness and In M. the surface is specimen peculiarities. squarrosa ex-
divide is here obvious well. tendency to as tremely smooth and even, making an almost
the of transparent impression. By presence
In the forms of the and tubercles it brief, growth three species numerous crests is, however, at
be follows: the time frilled. may diagnosed as same These outgrowths are
bladed Millepora complanata: or honeycombed. rather strongly developed in the type-specimen
General of the corals is rather loose, with of M. III but also in the aspect squarrosa (plate fig. 1),
divide in other all of them a tendency to the top parts of the cor- corals investigated; are of a allum. much smaller size than the but marked Growing edges generally sharp, type, a
towards surface still be sometimes truncated. tendency a frilled can
Millepora squarrosa: honeycombed. General observed.
without massive, a In M. striata the surface is due to aspect very compact, plates very uneven
divide in the tendency to top parts. Growing depressions lodging a central gastropore. (In
in colonies smooth and rounded. ZMA Coel. 8370 each and dac- edges young gastropore
striata: General is situated in Millepora honeycombed. aspect tylopore a depression.) Another
with of the loose, a feature in this is the of very pronounced tendency species presence
branch and divide in the plates to to top parts. longitudinal ridges, which are most pronounced
Growing edges very sharp. towards the growing edges (see plate IV fig. 1).
The growth form of the only remaining Both in M. alcicornis and in M. complanata the
M. is species, alcicornis, in general branched. texture of the surface is variable, but generally
The branches from vary extremely delicate the surface of M. alcicornis is smoother than that
I robust I of M. In both (plate fig. 1) to (plate fig. 2). They complanata. species gastropores
be fused in the basal of the corallum may parts may be situated in depressions but they may
that the form be to such a high degree growth also flush with the surface. 54 - 1984 247 BIJDRAGEN TOT DE DIERKUNDE, (2)
the surface be Time Summarizing, texture may of reproduction
helpful as a taxonomie character, but it is not Excepting the period March through June, cor- absolutely distinctive. als collected the No were throughout year.
seasonal differences in ampullae formation were Microstructure of the skeleton found between M. alcicornis and M. complanata.
The skeleton of consists of Both active in all months Millepora a porous, were reproductively
reticulation of solid bars and collected. regular supports of
aragonite. At the surface the skeleton is
somewhat lumpy, and consists of spherulitic Size of the pores
growths, illustrating the mode of growth and According to Boschma (1948 a: 51-54) the size thickening of the bars. Sorauf(1974: 39, pis. I, of the be of in pores may some help exceptional II, III, figs. 1-3) gives an extensive descrip- in M. intricata and M. cases only, e.g. tion of the skeleton of Millepora, but the only platyphylla, two Indo-Paciflc species. Martinez species involved in his study is M. alcicornis. It Estalella (1982) considered the size of the pores seemed therefore worth while to present here of M. alcicornis diagnostically useless because of some scanning electron microscope variation. In high intraspecific the present photographs of the four species treated in this study this character is examinedagain, but only V As taxonomie paper (plates & VI). a those parts of the corals are included which character the microstructure of the skeleton is in the condition were evidently same during useless, since all species exhibit the same varia- life. Shaded where the minute sides, pores are tion.
or even absent, are left out of consideration, as
well the as top parts of the corallum. Twenty Structure of the ampullae covering measured in each coral. pores were
In medusae in In table I and Millepora, originate special gastropore dactylopore
chambers in the skeleton (called ampullae), diameters of some specimens are shown. In
the size the which are covered by calcareous trabecular text-fig. 1 of gastropores of M.
the and M. is structures as long as medusae are not yet set alcicornis complanata plotted against
free. The taxonomie value of the of Different used structure water depth. symbols are to
the ampullae covering was investigated by discriminate between purely bladed corals of
Boschma who M. and those with (1949 a, 1950, 1964), finally con- complanata a honeycombed
cluded that this is Boschma's in- form. The diameter of the not diagnostic. growth gastropores
few corals but vestigation was limited by the seems to diminish with increasing depth,
closed and due the in shallow- possessing ampullae, only one to high variation, especially
the decrease is Caribbean species (M. alcicornis) was included water corals, not statistically
in his study. Among the corals collected by the significant (correlation analysis was carried out
for each data The present author (belonging to M. alcicornis and set). same applies to the
M. diameter of the which complanata), a high percentage appeared to dactylopores, of no figure
in closed also is the the carry ampullae condition; one given. Among two species gastropore specimen of M. striata in the ZMA collection and dactylopore sizes differ significantly
Coel. has few which but there is It is (ZMA 8371) a ampullae (p<0.05), an overlap. obvious
still closed. corals fall within are partly that the honeycombed the
In plate V ilg. 1, plate VI fig. 3, and plate variation of M. complanata. From this fact alone
the conclusion VII, ampullae coverings of the three species that they belong to M. complanata
is but are shown. Different structures of the ampullae not justifiable, their identity becomes
but established when the sizes covering were found, they were present firmly pore are com-
within coral and not of bined with the as will be shown even one are, therefore, pore densities,
diagnostic value. below. 248 W. H. DE WEERDT - CARIBBEAN MILLEPORA
M. has the and of M. are indicated in the with complanata largest gastropores squarrosa, figure
dactylopores (table I); the gastropores of M. different symbols.
rather those of M. alcicornis In table I the and squarrosa are large; gastropore dactylopore
and M. about of and striata are the same size, densities of some specimens are given.
rather small. Conspicuous is the difference in Gastropore size in combination with gastropore
size of the distinctive pores in M. squarrosa : the dac- density is not a character.
smaller than the tylopores are much the Summarizing, combination of dac-
M. striata and size with is gastropores. In both gastropores tylopore dactylopore density a
dactylopores are rather small. highly species specific character in the four
The size of the gastropores and dactylopores Caribbean Millepora species.
in is not a reliable diagnostic character by itself;
combination with the it pore density is,
distinctive however, most as is shown below. CONCLUSIONS
Reliable identification of the four Caribbean Pore density Millepora species, M. alcicornis, M. complanata,
For the like in the M. and M. striata is counting pores, measuring squarrosa, usually possible
of the when combination of characters is used. Most pore sizes, only comparable parts cor- a
allum used were (shaded sides, growing edges distinctive is the combination of dactylopore
etc. were left out of consideration). In this way, size with dactylopore density.
intracolonialvariation of the dactylopore densi- M. alcicornis and M. complanata have the
to be rather small: twelve random variation and in ty appeared largest overlap every character,
2 converted makes it often difficult counts of 0.09 cm (which were later which or sometimes even
2 sufficient obtain to cm ) appeared to 95% con- impossible to distinguish them. It is presumed
fidence intervals (Student-Newman-KeuPs that they are closely related species.
test).
In text-fig. 2 the diameter of the dactylopores
(mm) is plotted against dactylopore density SYSTEMATIC DESCRIPTIONS
of 2 (number dactylopores per cm ). The com-
bination dactylopore size / dactylopore density Millepora alcicornis Linnaeus, 1758
is in M. and M. I V highly species specific squarrosa (Plate figs. 1-3, plate figs. 1-2)
well from each striata; both species are separated For detailed cf. 1948 synonymy Boschma, a (except
other as well as from M. alcicornis and M. com- Millepora nitida Verrill, 1868), Boschma, 1949 b, and The planata. latter two species have an overlap, Weisbord, 1968.
which is, however, much smaller than the 1948 Millepora alcicornis;; Boschma, a: 23-28, 79-81, 86-88, in size. overlap gastropore 100-101, text-fig. 6, pi. XIV fig. 3; Boschma, 1949 b: The of the in M. high density dactylopores 661-663; Boschma, 1956: F94, fig. 76A; Goreau, 1959:
83; Stoddart, 1962: 109; Almy & Carrion Torres, 1963: squarrosa in combination with their relatively 141, 144, IIa; Weisbord, 1968: 16-21; Laborei, small size is pi. very conspicuous, even when a 1969: 222; Mergner, 1969: 279, 281, 286, pi. II; Roos, is with specimen studied a simple hand lens. 1971: 43, 44, pi. II; Goreau & Goreau, 1973: 436;
Boschma's unawareness of the of this validity Steam & Riding, 1973: 197-199, fig. 5c; Colin, 1978: character combination well demonstrated is by 137, 146, 150; Mattraw, 1979: 29-37, pi. I; De Weerdt,
his identification of M. 1981: 1-18, pi. I, pi. V figs. 1 & 2. some specimens as squar- alcicornis forma alcicornis; 1974: basis of their Millepora Scatterday, 86; rosa, on growth form: RMNH Martinez Estalella, 1982: 5-15, 24, figs. 4, 6a. ZMA 16876, Coel. 8372 and 8373 are without Millepora alcicornis forma delicatula Martmez Estalella, 1982 doubt M. complanata; ZMA Coel. 8370 and 5-7, 20, 23, 24, fig. 8. 8371 fall within the variation ofM. striata. Some ?Millepora alcicornis; Chevalier, 1966: 1390; Laborel, 1974: of these well specimens, as as the type-specimen 427, 439, 440. - 249 BIJDRAGEN TOT DE DIERKUNDE, 54 (2) 1984
Text-fig. 1. Gastropore diameter ofM. alcicornis and M. complanata plotted against water depth.
2. of in relation diameter Text-fig. Dactylopore density (number dactylopores per cm²) to dactylopore (mm). 250 W. H. DE WEERDT - CARIBBEAN MILLEPORA
Holotype: Millepora complanata Lamarck, 1816 Unknown, probably lost. (Plate II figs. 1-4, plate V figs. 3-4, plate VII
Material examined: fig- O
Curaçao and Bonaire: numerous specimens in ZMA col- For detailed cf. 1949b synonymy Boschma, 1948a; lection; RMNH 10504 (Curaçao).
Aruba: RMNH 10507. Millepora complanata;; Boschma, 1948a: 34, 35, 83, 84, 94,
West Indies: BMNH 42.10.26.43, 51.7.28.26. 95, 103, text-fig. 11, pi. VII fig. 2; Boschma, 1949b:
Saba: RMNH 8500, 8501, 8502, 8503. 665; Almy & Carrion Torres, 1963: 141, 144, pi. IIb;
St. Eustatius: RMNH 10588. Roos, 1971: 43-45, pi. Ill; Goreau s, Goreau, 1973:419,
Florida: RMNH 4954. 436; Steam & Riding, 1973: 197-199, lig. 5B; Colin,
1978: 140, 143, 150; Dc Weerdt, 1981: 1-17, pi. II figs.
1-3, pi. V figs. 3-4, pi. VI figs. 1-4.
Diagnosis: Millepora alcicornis forma complanata Scatterday, 1974: 86,
Habit: branches fig. 9; Martinez Estaleila, 1982: fig. 6 branching; may be very deli- 5-24, (right).
alcicornis forma 1974: and united into Millepora squarrosa Scatterday, 86; cate or coarse largely plate-like Martinez Estalella, 1982: 5-18, fig. 7. constructions; flattened at the growing edges. Boschma, 1948a: Millepora squarrosa (partim); 32, 33, 93, Corallum but it may mostly growing upright, 94, 102, pl. IX. also incrust etc. 1971: Stearn gorgonians, Millepora squarrosa; Roos, 44, pl. I; & Riding,
1973: 5A. Surface: rather smooth and even. 197-199, fig.
De 1981: 0.15-0.30 Millepora “squarrosa ;” Weerdt, 1-17, pis. Ill, Gastropores: mm. VII, Vili. 0.06-0.17 Dactylopores: small, mm.
Pore rather low, 5-50 per density: gastropores Holotype:
2 45-200 2 lost cm ; dactylopores per cm . Unknown, probably
Material examined:
Curaçao and Bonaire: numerous specimens in ZMA col- Ecology: lection, RMNH 10550 (Curaçao). Abundant at the less exposed sites of reefs and West Indies: BMNH, two specimens, no registration in lagoons. number.
Saba: RMNH 8511, 8512
Distribution: Diagnosis:
Caribbean (Boschma, 1948a; Goreau, 1959; Habit: colonies consisting of simple plates, from Stoddart, 1962; Almy & Carrión Torres, 1963; growing a common base, or complex of interconnected Weisbord, 1968; Mergner, 1969; Roos, 1971; masses plates forming
Colonies remain Goreau & Goreau, 1973; Stearn & Riding, 1973; honeycombed structures. may
dwarfish with base sites with Laborel, 1974; Scatterday, 1974; Colin, 1978; large incrusting on
action. De Weerdt, 1981; Martinez Estalella, 1982); strong wave Surface: from smooth rather Florida (Verrill, 1868; Boschma, 1948a); Ber- varying to rough, with rims the muda (Boschma, 1948a; Mattraw, 1969); Bra- sharp around pores. Often it is
with zil (Laborel, 1969); ? West Africa (Chevalier, uneven by depressions a central
1966; Laborel, 1974). gastropore.
Gastropores: large: 0.22-0.36 mm.
Dactylopores: variable, mostly rather large: Discussion: 0.12-0.24 mm.
M. alcicornis forma delicatula Martinez Estalella, Pore 10-70 2 45-250 density: gastropores per cm ; is delicate form of M. alcicornis. It is 1982, a very 2 dactylopores per cm . regularly found in Curaçao and Bonaire (ZMA
Coel. 8083, 8048, 8057, and several other speci- Ecology:
There is to it Abundant in the surf and reef flats. mens). no reason regard as a sepa- zone at rate since all characters fall bladed forms species or variety, Rheophylic, growing perpen-
of within the variation M. alcicornis. dicular to current direction. BIJDRAGEN TOT DE DIERKUNDE, 54 (2) - 1984 251
TABLE I
and diameters and and densities of of Gastropore dactylopore (mm) gastropore dactylopore (number pores per cm²) some
of alcicornis, M. M. and M. striata. in bold specimens Millepora complanata squarrosa, (Means are printed type, and standard
deviations between are given parentheses.)
2 2 diameter diameter species gastropore dactylopore n gastropores/cm n dactylopores/cm
M. alcicornis
ZMA Coel. 8029,
branching, 9 m 0.15-0.24(0.02)-0.25 0.08-0. 11(0.02)-0. 15 12-27.6( 7.8)-39 46-109.3(47.3)-189
ZMA Coel. 8004,
13 branching, m 0.15-0.21(0.04)-0. 28 0.08-0.09(0.02)-0. 13 8-22. 1( 8.3)-36 88-122.6(24.6)-146
ZMA Coel. 8045, almost
bladed by fused branches,
9 m 0.15-0. 20(0. 02)-0. 20 0.05-0. 11(0.03)-0. 18 23-33.5( 9.0)-50 78-118. 5(34.6)-208
ZMA Coel. 8083, very
delicately branched, 27 m 0.13-0. 20(0. 03)-0.25 0.05-0.07(0. 02)-0. 10 17-28. 9( 7.8)-46 92-162. 1(40.0)-203
ZMA Coel. 8048, very
delicately branched, 28 m 0.15-0. 20(0. 02)-0.25 0.05-0. 09(0. 03)-0. 10 10-24. 3( 8.0)-33 67- 94.5(22.2)-145
ZMA Coel. 8057, very
delicately branched, 2 m 0.18-0. 21(0. 02)-0. 25 0.05-0. 09(0. 02)-0. 15 23-27.7( 7.5V45 110-172. 8(22. 9V200
M. complanata
ZMA Coel. 8190,
bladed, 17 m 0.25-0. 28(0. 02)-0. 30 0.13-0.16(0.03)-0. 23 12-18. 4( 6.7)-35 50- 89.0(26.3)-133 ZMA Coel. 8165,
3 bladed, m 0.30-0. 32(0. 02)-0. 35 0.15-0. 24(0. 04)-0. 30 11-26.2(10.3)-46 47- 86.0(23.2)-124
ZMA Coel. 8143, boxwork, 3 m 0.20-0.28(0. 03)-0. 33 0.13-0. 16(0.03)-0. 23 23-28. 9( 6.3)-33 72-105. 0(15. 6)-123
ZMA Coel. 8216, boxwork, 1.5 m 0.25-0. 28(0. 02)-0. 30 0.10-0. 14(0.02)-0. 18 32-50.5(12. 9)-78 45-105.0(28.5)-136
ZMA Coel. 8172, boxwork, 2 m 0.25-0.28(0.04)-0. 35 0.15-0. 18(0.03)-0. 25 39-49. 5( 7.9)-67 136-187. 9(32. 6)-235
RMNH 16876, boxwork, depth unknown 0.30-0. 34(0.02)-0. 38 0.15-0. 18(0.02)-0. 23 17-32.3(1 1 ,6)-56 100-134. 2(23. 5) 167
M. squarrosa
MNHN type-specimen 0.18-0. 24(0.04)-0. 32 0.07-0.1 1(0.02)-0. 14 21-30.3( 6.4)-44 500-676. 8(95. 6)-816
RMNH 8515,
16 m 0.20-0. 25(0.02)-0. 30 0.08-0.09(0.02)-0. 10 1 1-29.8(12.5)-47 467-526.0(38.9)-567
RMNH 8514,
0-15 0.25-0. m 28(0. 02)-0. 30 0.08-0. 10(0.02)-0. 15 35-43. 8( 7.1)-56 378-484. 2(56. 2)-576
ZMA Coel. 8210,
3 m 0.23-0. 26(0. 02)-0.30 0.08-0. 09(0. 01)-0. 10 12-30.8(11 ,5)-59 475-536. 1(54. 7)-668
ZMA Coel. 8211,
depth unknown 0.20-0.29(0.03)-0. 33 0.08-0.09(0. 01)-0. 10 14-28. 0( 8.6)-46 356-564. 8(92.8)-756
M. striata
ZMA Coel. 8371,
depth unknown 0.15-0. 19(0.02)-0.23 0.10-0. 14(0.02)-0.18 10-30. 7( 8.6)-45 280-370.5(56.5)-488
ZMA Coel. 8370,
depth unknown 0.15-0. 19(0.03)-0.25 0.08-0. 10(0.02)-0.13 11-33.9( 9.9)-46 278-368. 6(58. 6)-500
Darmstadt Mus.
XI: 66- la, depth unknown 0.17-0. 20(0.02)-0.25 0.08-0. 11(0. 02)-0.15 24-38. 2( 8.8)-56 322-412.9(51,3)-512
RMNH 14771, depth unknown 0.15-0.20(0. 03)-0.25 0.08-0. 10(0. 01)-0.13 23-34. 8( 9.2)-44 356-416. 6(34. 4)-467 252 W. H. DE WEERDT - CARIBBEAN MILLEPORA
Distribution: rounded edges. In older colonies the growth
form becomes and the Caribbean. more plate-like, growing
edges sharper, but the plates remain connected
Discussion: along their whole length.
Surface: but the M. complanata is at the same time one of the very smooth, irregular by
and limited of crests and tubercles. commonest geographically most presence numerous
species. It is neither recorded from outside the Gastropores: 0.20-0.30 mm.
Caribbean region, nor from Bermuda (Mat- Dactylopores: very small, 0.07-0.15 mm.
10-60 2 dac- traw, 1969). It is well distinguished from M. Pore density: gastropores per cm ;
2 the size and of the dac- 480-750 squarrosa by density tylopore density very high: per cm .
but it has in rather tylopores, many respects a large overlap with M. alcicornis. Some Ecology:
specimens collected show a completely in- Unknown.
termediate growth form (ZMA Coel. 8045,
8050), and also in the other characters there is Distribution:
In the Puerto Rico Carrión always an overlap. addition, two species (Almy & Torres, 1963;
with less the in RMNH and ZMA are partly sympatric more or same Colin, 1978; specimens ecological preferences. It is presumed that they collections); St. Eustatius (specimens in
It worth ZMA Saba are two closely related species. seems RMNH and collections);
detailed their in RMNH Maria while to undertake a study on (specimens collection);
and Brazil reproductive patterns serological proper- Farinha, Pernambuco, (Boschma, 1962).
of which little is known. ties, very
striata Millepora Duchassaing & Michelotti, Millepora Lamarck, 1816 squarrosa 1864 (Plate III figs. 1-3, plate VI figs. 1-2) (Plate IV figs. 1-2, plate VI figs. 3-4, plate VII
Restricted fig- 2) synonymy
?Millepora folliata Milne Edwards, 1860 (reference in Millepora striata Duchassaing & Michelotti, 1864: 198, pi
Boschma, 1948a). XI fig. 8.
Millepora tuberculata & Michelotti, 1864: 198, 1948a: 32 Duchassaing Millepora squarrosa (partim); Boschma, pl. XI fig. 4.
1948a: Holotype Millepora squarrosa (partim); Boschma, 32, 33, pi lost VIII. Unknown, probably
Boschma, 1962: 306, 307, 308, pis. VI, Millepora squarrosa; Material examined
VII; Almy & Carrion Torres, 1963: 144, pi. Illa; San Bias: specimens of the Hessisches Landesmuseum, Colin, 1978: 140, 150. Darmstadt, labelled XI: 66-la, c, d and 66-lb, e, f;
RMNH 14771. Holotype: Venezuela: ZMA Coel. 8371 unknown 8370, MNHN, no registration number, locality
("Mers de l'Amérique", cf. Lamarck, 1816).
Material examined Diagnosis:
Habit: corallum of connected St. Eustatius: ZMA Coel. 8210, RMNH 8514 consisting loosely
Saba: RMNH 8513, 8515 (two specimens). which have plates, a strong tendency to divide Puerto Rico: RMNH 16877 donated (four specimens by in the top parts. Edges very sharp. Dr. T. Goreau to Dr. H. Boschma, cf. Boschma, 1962: the Surface: numerous longitudinal folds make 308). surface very uneven. Gastropores and dac- ZMA Coel. 8211, one specimen without data on locality tylopores often situated in pronounced depres-
Diagnosis: sions.
Habit: colonies consisting of irregularly, heavi- Gastropores: 0.15-0.25 mm. ly interconnected, stubby masses with smooth, Dactylopores: 0.08-0.18 mm. 54 - 1984 253 BIJDRAGEN TOT DE DIERKUNDE, (2)
2 Pore 10-50 dac- The western side of the Atlantic is density: gastropores per cm ; tropical
rather 270-500 2 divided into tylopore density high: per cm . biogeographically two provinces:
the Caribbean and the Brazilian region
of Ecology: (Laborel, 1969). The known distribution the
Unknown. Millepora species is shown in table II. This
distribution well with the pattern agrees very
Distribution: of other in distribution patterns coral species the
Guadeloupe (Duchassaing & Michelotti, 1864); Caribbean and Brazilian region (cf. Laborel,
San Bias (specimens of the Hessisches 1969). M. alcicornis has the widest geographical
and RMNH collec- from 32° Landesmuseum Darmstadt range: N (Bermuda; Mattraw, 1969)
tions); Venezuela (specimens in ZMA collec- to 25° S (coast of Brazil; Boschma, 1948a;
tion). Laborel, 1969). The West African record needs
verification. Specimens of Millepora from the
Islands in the RMNH. Discussion: Cape Verde are present
of Boschma intended describe them In Boschma's unfinished ms. no description to as a new
the species is given, but he mentions the species (unpublished ms.); the specimens do in-
which the peculiar longitudinal folds of the surface. deed have some peculiarities point to
Michelotti write in fact that be distinct from Duchassaing & (1864: 198) they might a species
their description: "superficie rugis in series M. alcicornis. However, even when West Africa longitudinales approximatis instructa". These is left out of consideration for the moment, M.
folds characteristic alcicornis still has wide distribution in the are very indeed, making M. a very striata of the easiest M. one recognizable Millepora western tropical Atlantic, whereas com-
species of the Caribbean. The distribution is planata, with which it is so easily confused, has a
limited it is not yet firmly established, since only three more distribution, although quite
reliable of localities known. The records are common all over the Caribbean. A possible ex-
found in and Bonaire. for the M. alcicor- species was not Curaçao planation differences between
nis and M. be different complanata may
similar BIOGEOGRAPHICAL REMARKS reproductive strategies, analogous to differences observed recently by Van Moorsel
Besides the four Millepora species treated in this (1983) in closely related, sympatric Agaricia
other described from paper, two species are the species. M. complanata possibly is an oppor-
Atlantic viz. M. braziliensis Ver- tunistic tropical region, species, well adapted to turbulent en-
1868 and M. nitida 1868. vironments and short larval rill, Verrill, They are possessing a stage excluded from this because of lack of study suf- preventing excessive loss of larvae in extreme ficient but it is intended revise all material, to circumstances, while M. alcicornis could have a
Atlantic of the when larval for representatives genus more longer life, intended greater settle- material is available. the basis of stable However, on ment success in highly competitive, en- the few specimens which could be studied for vironments (cf. also De Weerdt, 1981). comparison, it is tentatively concluded that M. Concerning relationships with Indo-Pacific braziliensis and M. nitida two other of the represent representatives genus, there are four valid and At in the Indo-Pacific which distinguishable species. present species are very their distribution is confined to the Brazilian These similar to Atlantic species. species are region (Laborel, 1969). Laborel (1.e.) has Millepora dichotoma Forskäl, 1775, and M. in- doubts about the difference between M. tricata Milne Edwards, 1857, which resemble braziliensis and M. from his M. M. squarrosa. Judging alcicornis; platyphylla Hemprich & figure VIII I conclude which resembles M. (pl. fig. 5) tentatively Ehrenberg, 1834, squarrosa; that his not with M. and specimens are conspecific M. exaesa Forskäl, 1775, which is similar to squarrosa. M. nitida Verrill, 1868. Boschma (1962: 310) 254 W. H. DE WEERDT - CARIBBEAN MILLEPORA
TABLE II
Known distribution of Millepora species in the tropical Atlantic region.
species Caribbean region Brazilian region Florida Bermuda West Africa Reference
M. alcicornis X X X X ? X see Systematic description
M. complanata X see Systematic description
M. braziliensis X Verrill, 1868
Boschma, 1961, 1962
Laborel, 1969
M. nitida X Verrill, 1868
Boschma, 1962
Laborel, 1969
M. squarrosa X X see Systematic description
M. striata X see Systematic description
latter the separates the two only on basis of their BOSCHMA, H., 1948a. The species problem in Millepora.
Zoöl. Verh. 1: I-XV. geographical distribution, but considers the two Leiden, 1-115, pis. , 1948b. Specific characters in Millepora. Proc. kon. in This species every respect indistinguishable. ned. Akad. Wet., 51 (7): 818-823. strongly points to a former Tethyan distribution 1949a. The of Proc. kon. ned. , ampullae Millepora. of the and to the existence of twin genus, species Akad. Wet., 52 (1): 3-14, pis. I-V.
1949b. Notes the in the Atlantic and Indo-Pacific oceans. on specimens of Millepora , genus
in the collection of the British Museum. Proc. zool.
ACKNOWLEDGEMENTS Soc. London, 119 (3): 661-672, pis. I II.
1950. Further notes on the of , ampullae Millepora.
I would like to thank the staff of the Caribbean Marine Zoöl. Meded. Leiden, 31 (5): 49-61, pis. I-VI. Institute for their Biological hospitality during my stay 1956. Milleporina and Stylasterina. In: R. C. , there. For the loan and study of specimens I am grateful to Moore ed., Treatise on invertebrate paleontology,
Dr. G. Scheer Landesmuseum, Darmstadt, (Hessisches F: Coelenterata: 90-107 part (Geological Society Germany), Mrs. J. Maréchal (Muséum National of America and University of Kansas Press, d'Histoire Naturelle, Paris, France), Dr. P. S. Cornelius Lawrence, Kansas). (British Museum (Natural History), London), and Drs. J. 1961. Notes on braziliensis Verrill. , millepora Historie, C. den Hartog (Rijksmuseum van Natuurlijke Proc. kon. ned. Akad. Wet., (C) 64: 292-296, Leiden, the Dr. R. P. M. Bak kindly Netherlands). pis. I II.
sincere thanks due to Prof. donated a specimen. My are , 1962. On milleporine corals from Brazil. Proc.
Dr. W. Vervoort for allowing the use of Boschma's un- kon. ned. Akad. Wet., (C) 65: 302-312, pis. I-VIII. manuscripts. Mr. C. Bakker (Laboratorium published 1964. Notes on the ampullae of two colonies of , voor Electronenmicroscopie, Amsterdam) instructed me in Millepora. Proc. kon. ned. Akad. Wet., (C) 67: thanked the use ofthe S.E.M., Mr. L. A. van der Laan is 195-200, pis. I-II. for the corals, Mr. Vermeulen for his photographing J. On of from Mauri- 1966. a new species Millepora , technical assistance, and Mr. J. Zaagman for assembling tius, with notes on the specific characters of Millepora the Drs. E. R. Osieck is thanked for his ad- plates. helpful Akad. exaesa. Proc. kon. ned. Wet., (C) 69: 409- vice. Dr. R. W. M. van Soest and Drs. Florence F. J. M. 419, pis. I-III. Pieters made constructive comments on the manuscript. CHEVALIER, J. P., 1966. Contribution à l'étude des
Madréporaires des côtes occidentales d'Afrique REFERENCES tropicale, 1-2. Bull. I.F.A.N., (A) 3: 912-975,
CARRION Shallow 4: ALMY, O. O. & C. TORRES, 1963. water pis. I-V, 1356-1405, pis. I-III.
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1-162. plants. A field guide to the invertebrates and plants BIJDRAGEN TOT DE DIERKUNDE, 54 (2) - 1984 255
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Bahamas and Florida: 1-512 (T.F.H. Publications, factors on the hydroid growth of some Jamaican
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DUCHASSAING DE FONBRESSIN, P. & J. MICHELOTTI, 1864. 1969: 275-290.
mémoire Supplément au sur les Coralliaires des MOORSEL, G. W. N. M. VAN, 1983. Reproductive
Antilles. Mém. Acad. Sci. 2 Turin, (3): 97-206, strategies in two closely related stony corals (Agaricia,
pis. I-XI. Scleractinia). Mar. Ecol. Prog. Ser., 13: 273-283.
T. 1959. The of GOREAU, F., ecology Jamaican coral Roos, P. J., 1971. The shallow-water stony corals of
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40: 67-90. 1-108, pis. I-LIII.
GOREAU, T. F. & N. I. GOREAU, 1973. The ecology of ScATTERDAY, J. W., 1974. Reefs and associated coral
Jamaican coral reefs, II. Geomorphology, zonation assemblages of Bonaire, Netherlands Antilles, and
and sedimentary phase. Bull. mar. Sci., 23 (2): their bearing on Pleistocene and Recent reef model.
399-464. Proc. 2nd Int. Coral Reef Symp., 1. Great Barrier
S. 1898a. On the of the Reef Brisbane: 85-106. HICKSON, J., species genus communities,
communication. Millepora: a preliminary Proc. zool. SORAUF, J. E., 1974. Observations on microstructure
Soc. London, 1898: 246-257. and biocrystallization in coelenterates. Biomineraliza-
, 1898b. Notes on the collection of specimens of tion, 7: 38-55.
the obtained Mr. C. W. R. 1973. Forms of the genus Millepora by Stanley STEARN, & RIDING, hydro-
Gardiner at Funafuti and Rotuma. Proc. zool. Soc. coral reef. zoan Millepora on a recent Lethaia, 6:
London, 1898: 828-833. 187-200.
LABOREL, J., 1969. Madréporaires et Hydrocoralliaires STODDART, D. R., 1962. The Caribbean atolls: Turniffe,
récifaux des côtes brésiliennes. Systématique, écolo- Lighthouse reef, and Glover's reef, British Hondu-
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1974. West African reef an on and 4. Notice of , corals, hypothesis genera species, the corals and
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naturelle des animaux 2: 1-568 W. H. 1981. sans vertèbres, i-iii, WEERDT, DE, Transplantation experiments
(Imprimerie d'Abel Lanoe & Verdière, Libraire, with Caribbean Millepora species (Hydrozoa, Paris). Coelenterata), including some ecological observa- MARTINEZ N., 1982. Sistematica del ESTALELLA, gènero tions on growth forms. Bijdr. Dierk., 51 (1): 1-19.
Millepora datos sobre N. 1968. Some (Hydrozoa: Milleporidae) y WEISBORD, F., late Cenozoic stony
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Received: 6 July l!<84 256/I W. H. DE WEERDT - CARIBBEAN MILLEPORA
PLATE I
branched Coel. 1, Millepora alcicornis, very delicately (ZMA 8053).
the basal Coel. 2, Millepora alcicornis, branches stouter and fused in parts (ZMA 8074).
3, Millepora alcicornis, detail of surface (ZMA Coel. 8074) (g = gastropore, d = dactylopore). - 257/II BIJDRAGEN TOT DE DIERKUNDE, 54 (2) 1984
PLATE II
1, Millepora complanata, boxwork growth form (ZMA Coel. 8213).
dwarfish boxwork form Coel. 2, Millepora complanata, young colony, growth (ZMA 8216).
3, Millepora complanata, bladed growth form (ZMA Coel. 8006).
4, Millepora complanata, detail of surface (ZMA Coel. 8006) (g = gastropore, d = dactylopore). 258/III W. H. DE WEERDT - CARIBBEAN MILLEPORA
PLATE III
1 Millepora squarrosa, type-specimen.
with smooth actual size 2, Millepora squarrosa, young colony edges, (RMNH 8514).
3, Millepora detail of surface = d = squarrosa, (type-specimen) (g gastropore, dactylopore). 54 - 1984 259/IV BIJDRAGEN TOT DE DIERKUNDE, (2)
PLATE IV
1, Millepora striata (Landesmuseum Darmstadt XI: 66-1b).
detail of surface = d = 2, Millepora striata, (g gastropore, dactylopore). 260/V W. H. DE WEERDT - CARIBBEAN MILLEPORA
PLATE V
Scanning electron microscope photographs (g = gastropore, d = dactylopore, a = ampulla):
surface 1, Millepora alcicornis, with numerous ampullae in closed condition (ZMA Coel. 8374).
2, Millepora alcicornis, microstructure of skeleton (ZMA Coel. 8374).
3, Millepora complanata, surface (ZMA Coel. 8006). 4, Millepora complanata, microstructure of skeleton (ZMA Coel. 8006). - 261/VI BIJDRAGEN TOT DE DIERKUNDE, 54 (2) 1984
PLATE VI
d = ca = closed Scanning electron microscope photographs (g = gastropore, dactylopore, ampulla, oa = open ampulla):
surface Coel. 1, Millepora squarrosa, (ZMA 8211).
microstructure of skeleton Coel. 2, Millepora squarrosa, (ZMA 8211).
with closed and Coel. 3, Millepora striata, surface open ampullae (ZMA 8371).
4, Millepora striata, microstructure of skeleton (ZMA Coel. 8371). 262/VII W. H. DE WEERDT - CARIBBEAN MILLEPORA
PLATE VII
electron = closed = Scanning microscope photographs (ca ampulla; oa open ampulla):
1, Closed ampulla of a specimen of Millepora complanata (ZMA Coel. 8005).
2, Detail of ampullae of the specimen of Millepora striata of pl. VI fig. 3.