Sponges, Genus Mycale (Poecilosclerida : Demospongiae : Porifera), From A Caribbean Mangrove And Comments On Subgeneric Classification

37 Pages·1998·13.5 MB·

by  E Hajdu

PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
lll(4):737-773. 1998.
Sponges, genus Mycale (Poecilosclerida: Demospongiae: Porifera),
from a Caribbean mangrove and comments on
subgeneric classification
Eduardo Hajdu and Klaus Rutzler
(EH) Institute of Systematics and Population Biology, University of Amsterdam,
P.O. Box 94766 1090-GT, Amsterdam, The Netherlands;
Present address: Departamento de Invertebrados, Museu Nacional,
Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, s/n 20940-040, Rio de Janeiro,
RJ; and Centro de Biologia Marinha, Universidade de Sao Paulo, Sao Sebastiao, SP, Brazil;
(KR) Department of Invertebrate Zoology, National Museum of Natural History,
Smithsonian Insdtution, Washington, D.C. 20560, U.S.A.
—
Abstract. Eight species of Mycale Gray (Mycalidae, Poecilosclerida, De-
mospongiae) are described from marine mangroves on the barrier reef of Be-
lize, Central American Caribbean. Two are new: Mycale (Aegogropila?) car-
migropila and M. (Ae.) citrina. Other species found are M. {Ae.) arndti, M.
(Arenochalina) laxissima, M. (Carmia) magnirhaphidifera, M. (C.) microsig-
matosa, M. (Mycale) laevis and M. (Paresperella) sp. A key to the 17 recog-
nized Caribbean species of Mycale is provided. Ectosomal skeletal patterns
currently used as diagnostic characters for subgenera ofMycale may be inad-
equate for phylogenetic analysis, but reliable alternative congruent traits have
not yet been identified to replace these.
More than 150 species of Mycale Gray have strengthened the need for a better as-
have been described worldwide (Doumenc sessment of the genus' biodiversity, for a
&
Levi 1987), with representatives in most stable system of classification, and for bet-
marine habitats. They are common in both ter descriptions to differentiate between al-
polar and tropical seas, and have been re- lopatric sibling species.
ported from intertidal pools abyssal depths It has been convincingly argued that de-
(Hartman 1982). Contemporary mono- scriptions ofMycale are often unreliable in
graphs have added great numbers of new respect to noting size categories of micro-
species (Levi 1963, van Soest 1984, Berg- scleres (Hentschel 1913, Doumenc & Levi
quist & Fromont 1988, Hajdu & Desquey- 1987). Accordingly, special attention was
roux-Faundez 1994), indicating that many here paid to this important characteristic.
more undescribed taxa are yet to be found. Details of microsclere shape too were long
Our study ofthe rich marine mangrove eco- considered to be useful characters because
system of Belize (Rutzler & Feller 1988, of their low adaptive value (Ridley & Den-
1996; de Weerdt et al. 1991) is no exception dy 1887, Dendy 1921, Hajdu et al. 1994a,
&
and has revealed two new species of Myc- Hajdu Desqueyroux-Faundez 1994). This
ale. Recent findings of metabolites with view is adopted here and supported by our
pharmacological potential from species of scanning electron micrography.
Mycale (e.g.. Capon & Macleod 1987; Per-
Materials and Methods
ry et al. 1988, 1990; Fusetani et al. 1989;
Corriero et al. 1989; Butler et al. 1991; Sponges were collected by the authors
Northcote et al. 1991; Hori et al. 1993) and Kathleen P. Smith during several sur-
738 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
ft?-SouthWaterCay
''BlueGround
!s?- Range '•-''CarrieBowCay
It' ^-c^
:...•CurlewBonk
km 100m
1
Fig. L Map ofcollecting area on the barrier-reefplatform ofBelize. Geographical coordinates forprincipal
localities are 16°48.18'N, 88°04.93'W, Carrie Bow Cay; I6°49.95'N, 88°06.34'W, Twin Cays; and 16°48.55'N,
88°08.89'W, Blueground Range.
veys of mangroves in the vicinity ofCarrie scanning electron microscopy (SEM) were
Bow Cay, Belize (16°48'N, 88°05'W) (Fig. prepared in one of the two following ways:
1). Specimens are deposited in the sponge Samples in ethanol were washed of debris
collection of the National Museum of Nat- with several jets of ethanol, air dried in an
ural History, Washington, subsamples were oven, and mounted on SEM stubs by ap-
donated to the Museu Nacional, Universi- plying a thin layer of Entellan (Merck);
dade Federal do Rio de Janeiro, Brazil. samples from ethanol were washed in warm
Schizotypes of the two new species were water (ca. 1 min), immersed in a saturated
also deposited in The Natural History Mu- solution ofsoda, and heated to 50-70°C (30
seum, London, Queensland Museum, Bris- min). Then they were again washed in
bane, and Zoologisch Museum Amsterdam. warm water (1 min) and etched in 20%
Most anatomical preparations were made HNO3 at room temperature. After a few
according to Riitzler (1978) and Hajdu minutes under observation, samples were
(1994). Additionally, skeletons for study by rinsed with warm-water jets (1 min) and a
VOLUME 111, NUMBER 4 739
few drops of hydrogen peroxide (H2O2) so- ston, 1842 (misspelled as H. aegogropila)
lution added to the last change ofwater. Af- as a type-species of Aegogropila (Thiele
ter 30 min at 50-70°C the samples were 1903) overlooked Gray's (1867) name, Ae-
rinsed in warm water (1 min), transferred gogropila varians. BecauseAe. varians was
to ethanol (96%, 30 min), air-dried in an probably a replacement name in order to
oven, and mounted on SEM stubs. avoid tautology, although not clearly stated
Abbreviations used are: BMNH (The so by Gray (1867), we choose the figured
Natural History Museum, London), INV- specimen of H. aegagropila in Johnston
POR (Invemar-Porifera Collection, Univer- (1842, BMNH 1847.9.7.39) as lectotype of
sidad Nacional de Colombia, Santa Marta), Ae. varians. In this way, both species be-
MCZ (Museum of Comparative Zoology, come objective synonyms. This point was
MNHN
Harvard University, Cambridge), made clear by L. B. Holthuis (in lit.).
(Museum National d'Histoire Naturelle, The plasticity reported here for the pres-
Paris), MNRJ (Museu Nacional, Universi- ence of ectosomal reticulation in Mycale
dade Federal do Rio de Janeiro), MSNG {Ae.?) carmigropila new species is taken as
(Museo Civico di Storia Naturale di Gen- indication that some representatives ofCar-
MUT
ova), (Museo della Universita di To- mia (see below) are more closely related to
rino), NNM (NationalNatuurhistorischMu- Aegogropila than to other species of Car-
QM
seum, Leiden), (Queensland Museum, mia, suggesting paraphyly of the former
Brisbane), UFRJPOR (Universidade Fed- subgenus and polyphyly of the latter. Ad-
eral do Rio de Janeiro, Porifera collection), ditionally, some M. (Mycale) species may
USNM (National Museum of Natural His- have their confused tangential ectosomal
tory, Washington), and ZMA POR (Zoolo- skeleton developed so thinly as to make
gisch Museum Amsterdam, Porifera collec- spicules strewn at random appear reticulat-
tion). ed to the casual observer (cf. M. [M.] thielei
Hajdu & Desqueyroux-Faundez 1994).
Systematic Descriptions Species like this have been assigned to Ae-
gogropila in the past, for instance M. (M.)
Order Poecilosclerida Topsent, 1928 flagelliformis (Bergquist & Fromont, 1988)
Suborder Mycalina Hajdu et al., 1994 which has pore-grooves and a confused ec-
GenuFsamMiylcyaMlyecaGrlaiyd,ae18L6u7n;dbseecnks,u H1a9j05du & tthoesommaolnospkheylelteotni.cItsbtaetcuosmeosf aApepgaorgernotptihlaat
Desqueyroux-Faiindez 1994 may not hold up in a thorough revision of
—
Diagnosis. Mycalidae with skeleton of all species. Such a revision is not yet pos-
subtylostyles and palmate anisochelas; ad- sible, given that collections are dispersed,
ditional microscleres may include sigmas, many new taxa are still being discovered,
toxas, micracanthoxeas, raphides, unguifer- and, more importantly, no other congruent
ate anisochelas, and palmate isochelas. characters are yet apparent to replace the
existing system.
Subgenus Aegogropila Gray, 1867
— Mycale {Aegogropila) amdti van Soest,
Diagnosis. Mycale with tangential ec- 1984
tosomal skeleton of reticulate spicule tracts Figs. 2, 3, 17a; Table 1
(often easily peeled off), without serrated —
sigmas. Type species: Aegogropila varians Esperia macilenta. Carter 1871:276, pi.
Gray, 1867 (=M. [Ae.] contarenii [von 17, fig. 8; not Hymeniacidon macilenta
Martens, 1824, as Spongia contarenii.]). Bowerbank, 1866 {—Mycale {Carmia)
—
&
Remarks. Bergquist Fromont (1988) macilenta).
—
in quoting Halichondria aegagropila John- Mycale macilenta. Amdt 1927:143, in
740 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 2. Mycale arndti, skeleton: a, Peeled-off surface showing ectosomal reticulation; scale equals 500 |xm;
b. Detail of surface reticulation showing sigmas-I disposed around the bundles ofmegascleres, and disposition
of rosettes (R) in the comers of the meshes; scale equals 100 |xm; c, d. Fusiform subtylostyles and all four
categories ofanisochelas (I-IV); scale equals 100 |xm. (a-c, USNM 39329; d, holotype ZMA FOR 3675.)
—
part (not the figured specimen); not Hy- Description. Macroscopic appearance:
meniacidon macilenta Bowerbank, 1866 Grayish blue to gray crust or cushion with
(=Mycale (Carmia) macilenta). oscules often raised like small chimmneys;
M. (Aegogropila) arndti van Soest, 1984: non-slimy when rubbed. Preserved material
19, pi. II, fig. 1. Zea 1987:140. is composed of seven main fragments, the
Material studied.—ZMA POR 3675, ho- largest is 55 mm long, 30 mm wide, and up
lotype, Curagao; ZMA POR 3842, paratype, to 4 nam thick. The color in alcohol is drab
Florida. USNM 43032, Belize, Twin Cays, or pink, varying from light pink to almost
Batfish Point, <1 m, coll. K. Riitzler, 27 violet. The fragments have firm consistency
Apr 1989; USNM 39329 (MNRJ 630), Be- and microhispid surface texture. The ecto-
lize, Blue Ground Range, 1 m, coll. E. Haj- some has sand grains embedded in the sur-
du & K. Smith, 12 Aug 1993; USNM face and is easily peeled off. No oscules are
47871, Blueground Range, on red-man- apparent.
grove stilt root, <1 m, coll. K. Smith, Nov Skeleton: The ectosomal skeleton is a
1996. tangential reticulation of 120 |xm thick sub-
—
Diagnosis. Bluish, crustose Aegogro- tylostyle bundles (Fig. 2a), with no appar-
pila with sigmas (three categories) and tox- ent cementing spongin. Meshes are mostly
as; four categories of anisochelas, with cat- triangular and up to 400 X 200 fxm in di-
egories II and IV having exceptionally long ameter Microscleres occur in abundance
frontal alae (alae of head and foot nearly and may be playing the structural role of
fused), covering the entire shaft in frontal holding the reticulation intact. Sigmas I (as
view. many as 10 per linear mm) and rosettes
VOLUME 111, NUMBER 4 741
(135 |xm, 6 per mm) of anisochelas I can tial if a morphological-phylogenetic classi-
be seen surrounding the megasclerebundles fication of Mycale is to be achieved. In
(Fig. 2b). These and other microscleres, oc- many taxonomic descriptions, one or the
cur in great numbers inside the meshes. other microsclere category is often over-
The choanosome area appears light looked or lost to lumping decisions, as in
brown in transmitted light, with dark-brown the present species where anisochelas-cat-
blotches offibrous spongin. The spiculation egory III was not recognized by previous
here is not very dense and no clear pattern authors (van Soest 1984, Zea 1987). Con-
is apparent which may be due to the slightly sequently, anisochelas II of M. arndti
macerated condition of the specimen. Mi- should be described as arcuate because the
croscleres are scattered throughout this lateral alae of the head are partly separated
area. from the shaft (Hajdu et al. 1994).
Spicules (Figs. 2c, d, 3; Table 1): Sub- The stout sigmas I are comparable to
tylostyles fusiform, gradually tapering to a those of Esperella simonis as figured by
point, generally slightly bent in upper third Ridley & Dendy (1887) and of M. quadri-
and thickest at mid length, with long neck partita Boury-Esnault (Hajdu & Desquey-
and eliptical head. Anisochelas I stout, with roux-Faundez 1994), and may be homolo-
head length 50% oftotal length, foot in side gous to the diancistras ofHamacantha Gray
view at about 110° angle to shaft; frontal (Hajdu 1994). This similarity is based on
alae of foot may bear denticulation on top the straight inner face and the abrupt taper-
(Fig. 3e). Anisochelas II similar to aniso- ing of the hooks in this type of sigma and
chelas I but even stouter, with head length is enhanced by a faintly marked notch at
70% of total length, shaft not visible in mid-length of some of these spicules (Fig.
frontal view, lateral alae of head arcuate. 3h). Toxas show a remarkable range of size
Anisochelas III slender, with head length but size-frequency analysis of 100 toxas in
70% of total length, shaft slightly bent at the Belizean specimen failed to reveal dis-
the end of the lateral alae of the head. An- tinct categories.
isochelas IV very slender, with both frontal
alae prolonged into thin, digitiform pro- Mycale (Aegogropila?) carmigropila,
cesses that sometimes cross each other. Sig- new species
mas I stout, abruptly bent into very sharp Figs. 4, 17b; Table 2
hooks, with almost straight innerfaces. Sig-
—
mas II slender, with gradual curve and Type material. Holotype, USNM
sharp hooks. Sigmas III similar to sigmas 34560, Twin Cays, Sponge Haven, on roots
IIbut smaller. Toxas very gentlybent (more of Rhizophora, 1 m, coll. E. Hajdu & K.
pronounced in short forms). Smith, 17 Aug 1993. Paratypes: USNM
—
Ecology. Associated with mangrove 42997, BeHze, Twin Cays, Batfish Point, on
and shallow seagrass bottoms in bays and red-mangrove stilt root and peat bank, <1
lagoons. — m, coll. K. Riitzler and K. Smith, 5 May
Distribution. Florida, St. Vincent (Vir- 1986; USNM 43048, BeHze, Twin Cays,
gin Islands),—Curasao, Colombia, Belize. Hidden Creek, on red-mangrove stilt root,
Remarks. Only one of this species <1 m, coll. K. Riitzler, 8 May 1987; USNM
specimen was found, suggesting that it may 43047, Behze, Twin Cays, Hidden Creek,
be uncommon in the survey area. Details of encrusting a cluster of algae, genus Hali-
spicule morphology and presence of four meda, <1 m, coll. K. Smith, 8 May 1987;
types ofanisochelas agree well with the ho- USNM 47870, Belize, Twin Cays, Sponge
lotype (Figs. 2d, 3b-d). Haven, peat bank with algae, genus Hali-
It should be emphasized that proper as- meda, 1 m, coll. K. Smith, 5 Jul 1990;
sessment ofmicrosclere categories is essen- USNM 34561, Twin Cays, Sponge Haven,
742 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASfflNGTON
Fig. 3. Mycalearndti, spicules: a. Face viewofanisochela-I; scaleequals 10 [xm;b.Faceviewofanisochela-
II showing robustness and extremely long frontal ala ofhead, almost fusing with foot; note deeply concave top
portion of frontal ala ofthe foot (arrow); scale equals 10 iJim; c. Oblique frontal view of anisochela-III; scale
equals 5 jjim; d. Profile view of anisochela-IV showing thin digitiform prolongations from both frontal alae
(arrows) almost fusing; scale equals 5 |xm. e. Detail offoot ofanisochela-I in Fig. 3a showing tridentate (t) top
VOLUME 111, NUMBER 4 743
on roots ofRhizophora, 1 m, coll. E. Hajdu other two specimens USNM 34561, 38768
& K. Smith, 17 Aug 1993; USNM 34587, lack the specialized tangential ectosomal
Twin Cays, Sponge Haven, on roots ofRhi- skeleton, having just a few scattered me-
zophora, 1 m, coll. E. Hajdu & K. Smith, gascleres, rosettes, and abundant sigmas
17 Aug 1993; USNM 38768, Twin Cays, near the surface.
Sponge Haven, on Halimeda, 1 m, coll. E. The choanosomal skeleton is relatively
Hajdu & K. Smith, 17 Aug 1993. Schizo- low in spicule density, which accounts for
BMNH
types from holotype, 1994.3.1.1, the extreme softness and fragility. Subty-
QM G313152, MNRJ 631, ZMA POR lostyles occur scattered in great numbers
10708; fragments ofparatypes, MNRJ 632, and also form longitudinal bundles (<30
633, 634. — |jLm wide), frequently meandriform, thatend
Diagnosis. Intensely blue to greenish, in fan-like brushes (<500 ixm wide) in the
encrusting Mycale (Aegogropilal) with
subectosome. These brushes support the
three categories ofanisochelas and one type tangential ectosomal reticulation, when
of small (<70 |xm) sigmas.
— present, or the rosettes alone; generally, fi-
Description. Macroscopic appearance:
bers protrude slightly from the surface of
Specimens were encrusting (^20 cm^) on
the sponge.
roots of Rhizophora, or occurred intermin-
Spicules (Fig. 3, Table 2): Subtylostyles
gled with Halimeda. In the first case they
slender, slightly fusiform, straight or slight-
were cobalt-blue, while in the second they
ly bent in central part, with eliptical head
appeared very light green. Other specimens
well marked, shaft gradually tapering to a
observed alive were blue to violet, turning
tan when dying. Subectosomal canals con- sharp point. Anisochelas I with straight
shaft, head 40% oftotal length; frontal alae
verging on oscules in a star-like pattern are
forming narrow angle (30°) with shaft (pro-
visible in live specimens. The consistency
is very soft, slimy, and fragile, the texture file view), frontal alae of feet lower than
lateral alae, general aspect narrow in both
rather smooth.
Skeleton: The ectosomal skeleton is a frontal and profile views. Anisochelas II
polymorphic feature in this species. Two shaft markedly bent at head 50% of total
specimens (USNM 34560, 34587) have a length, lateral alae ofhead longerthan fron-
tangential reticulation of subtylostyles, sin- tal alae. Anisochelas III very slender, with
gle or in 50 |xm thick bundles, with large shaft gradually curved in profile view, head
amounts of cementing spongin. Meshes are 40-50% oftotal length, frontal alae offoot
mostly triangular (250 X 150 |xm). Up to distally extended by angled spurs. Sigmas
12 pores (40 X 20 to 80 X 50 fxm in di- with markedly bent hooks, gradually sharp-
ameter) of the aquiferous system can be ening ends. —
seen within a single mesh. A few rosettes Etymology. ^The name carmigropila is
of anisochelas I (^110 |xm in diameter), derived from the juxtaposition of Carmia
and sigmas I occur scattered among the and Aegogropila. These are the two sub-
meshes, frequently around the bundles. The genera with which specimens of this spe-
portion offrontal ala; scale equals 10 iJim; f. Oblique view from the back ofan anisochela-II showing arcuate-
like pattern exhibited by the lateral alae ofits head, which are elongated (arrow), rather than cut-offfrom the
shaft; scaleequals 5 |xm; g. Profileviewofcleistochela-Iikeanisochela-IVshowingthindigitiformprolongations
from both frontal alae intercrossing each other (arrows); scale equals 5 jxm; h, S-shaped, diancistra-like sigma-
I showing almost straight inner-face of hooks (h), and rare, notch-like constriction (n) at tortion point; scale
equals 20 |xm; i, Sigma-II; scale equals 5 |JLm;j, Sigma-III; scale equals 5 \x.m.; k, Toxas ofstable geometry, but
variable length; scale equals 20 |xm. (a, e-k, USNM 39329; b-d, holotype ZMA POR 3675.)
744 PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 4. Mycale carmigropila, spicules: a, Terminations of subtylostyles; scale equals 10 ixm; b. Face view
ofanisochela-I showing narrow aspect; scale equals 10 |jim; c, Profile view ofanisochela-I; scale equals 10 |xm.
d, Profile view ofanisochela-II showing narrow aspect, and shaft markedly bent at middle portion; scale equals
5 [Jim; e. Profile-view ofanisochela-III, note short, and thin digitiform spuron top offrontal alaoffoot (arrow);
scaleequals5 |jLm;f, Sigma; scaleequals20|xm. (a,d-f,Aegogropila-likeholotype,USNM34560;b,c, Carmia-
USNM
like paratype, 34561.)
VOLUME 111, NUMBER 4 745
cies show affinities in ectosomal skeletal
patterns.
—
Ecology. OnRhizophora mangrove stilt
roots and Halimeda algae bordering a large
mangrove channel with strong water flow.
—
Distribution. Belize.
—
Remarks. Of the four specimens stud-
ied, two have Aegogropila-\\k& ectosomal
skeletons and two lack it, thus resembling
Carmia (Arenochalina species are also
withoutectosomal skeleton butinsteadhave
a stout choanosomal reticulation). Both
forms are indistinguishable in the field and
have identical spiculation. The assignment
o to Aegogropila is tentative but justified by
iii 0?
the view that the ectosomal reticulation is
2 ^ On X more likely to be lost in a species of Ae-
X 4 gogropila than acquired spontaneously in
one of Carmia.
Mycale {Aegogropila?) carmigropila is
close to Mycale {Carmia) magnirhaphidi-
fera (see below) except for the possession
of one more category of anisochelas, slight
differences in the shape of anisochelas and
lack of raphides and of a second category
of sigmas. Both species may have blue or
bluish color in life.
Mycale {Aegogropila) citrina, new species
Figs. 5, 6, 17c; Table 3
Mycale americana van Soest, 1984:22 (in
part).—Zea 1987:138.
—
USNM
Type material. Holotype,
T T T T 38942, Twin Cays, Cuda Cut, 1 m, coll. E.
Hajdu & K. Smith, 13 Aug 1993. Paratypes,
IT) USNM 43031, Belize, Twin Cays, Cuda
Cut near Batfish Point, encrusting a cluster
2? o; of algae, genus Halimeda, <1 m, coll. K.
2 X r'07^\ 4V'^ 7^0^0 0V^0 R3i8i9t5z8le,r,3829763,Ap3r896179,89;TwiUnSNCaMys,38C9u5d6,a
Cut, 1 m, coll. E. Hajdu & K. Smith, 11
Aug 1993; USNM 47872, BeUze, Twin
Cays, Cuda Cut, peat bank, <1 m, coll. K.
o ^ o,00 Riitzler, 10 May 1997; USNM 41443 Be-
o (^ lize, Twin Cays, Cuda Cut, peat bank, <1
3 a, m, coll. K. Rutzler, 10 May 1997. Schizo-
'^63^ BMNH
6 types from holotype, 1994.3.1.2,
u N N QM G313153, MNRJ 635, and ZMA POR
' '
746 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
10709; fragments ofparatypes, MNRJ636-
'(TO) vro^ 0ir0i 639. —
Diagnosis. Lemon-yellow crustose Ae-
l>yd-) 0l0O 1^/-) gogropila with three categories of aniso-
(uNoI CirNIi i-^nI chelas, one type oflarge sigmas (>60 |xm),
and copious mucus production when han-
dled.
—
Description. Macroscopic appearance:
-* m ;2; ^ Thick incrustations (5 mm; 30 cm^) with
-i, K JJ ^5 protruding oscules encircledby athinmem-
i <N
brane. Extremely soft and fragile, and re-
CT) i (N1 1 leasing copious amounts of mucus upon
handling. Live-color is lemon yellow to
light orange, turning pale yellow in alcohol.
Numerous, pronounced subectosomal chan-
_
(N (rNo (-N^ nels may cover most of the sponge surface
> O
-~. and converge toward the oscules. Most
specimens contained embryos during Au-
00I OnI 0\I
gust.
Skeleton (Fig. 5): The ectosomal skele-
ton peels off easily and is made of a re-
o markably pure (no scattered megascleres)
t~- lO
tangential reticulation of bundled (:^85 |xm
ilrOi (0s0i CK) thick) subtylostyles (Fig. 5a), mostly form-
ing triangular meshes (660 X 400 |xm),
with no apparent cementing spongin. Ro-
settes ofanisochelas-I (130 jjim indiameter)
occur in places (Fig. 5b, c). Sigmas arevery
(^ OS vO abundant, scattered among the meshes (up
^Os'I (KNI «^^I to 35 per mesh), and along the strands (30
^XI XNOI X^I per mm; Fig. 5d); they seem to play an im-
portant structural role in the skeleton.
rNOoO rrr)oo Omn The choanosome is crowded with dark-
fNl OKn > brown granules (about 40 |xm in diameter),
frsNi On ~3~0: presumably of mangrove peat, which ham-
IV-, (N) f\|
Or-Ii 0—0I nm^I per observation of the skeletal architecture.
r»^ CN The underlying pattern seems to be densely
spicular, with crisscrossing megasclerebun-
dles (150 ixm thick) and abundant micro-
scleres.
^^ m(N er<n-) m^ Spicules (Fig. 6, Table 3): Subtylostyles
^i N1—O1 N^-O1 N>-On straight, slender and slightly fusiform, with
2a: ez< cz^ zcsi poorly marked eliptic head. Anisochelas I
S'^— S S S with straight shaft, head 50% of total
Nm^moO N(^U--OHD) m^I0rT0-) r0(N0^O0n0 hleenagdt,h.heAandis5o0ch-e6l0as%-IoIf twoittahl lsehnagftth;bfernotntaalt
S S S S alae offoot with short, digitiform processes
Z z z z
0P0 c^ 0D0 00 oDn on top (Fig. 6c). Anisochelas-Ill very slen-
1 H) der, with shaft gradually curved (profile