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PEABODY MUSEUM OF NATURAL HISTORY

YALE UNIVERSITY
NEW HAVEN, CONNECTICUT, U.S.A.

Number 103 10 November 1966

A NEW SPECIES OF CLATHRIID SPONGE
FROM THE SAN JUAN ARCHIPELAGO

Tracy L. SIMPSON
DEPARTMENT OF BIOLOGY, TUFTS UNIVERSITY,
MEDFORD, MASSACHUSETTS

INTRODUCTION

In the course of investigating the cytology of clathriid sponges
a new species from the San Juan Archipelago, Washington, has
been found. On the basis of skeletal and field characteristics this
form appears to be identical to chela-containing sponges described
by de Laubenfels (1927) from California as variants of Ophlita-
spongia pennata (Lambe, 1894). Cytological evidence reviewed
here (see Simpson, in press, for detailed discussion) establishes
that the chela-bearing sponges are not conspecific with O. pennata.

METHODS

Spicule preparations were made by digesting a piece of the
sponge in hot, concentrated nitric acid. This was followed by
repeated centrifugation and resuspension in distilled water. The
spicules were then dried on slides and mounted. Hand sections
were cut with a razor blade, stained in a saturated solution of basic
fuchsin in 95% ethanol, mounted and examined. Routine histo-
logical procedures and histochemical staining were employed for
studying cell types and microanatomy (see Simpson, in press, for
details of methods).

N

Postilla Yale Peabody Museum No. 103

DESCRIPTION
Axocielita hartmani new species

Ho.LotyPe: YPM’ No. 5075. Kilpatrick’s shore, San Juan
island, San Juan Archipelago, Washington, U.S.A.

Hasirat: A single specimen was collected growing on a rock
substratum at two feet below mean low water level.

FURTHER DISTRIBUTION: De Laubenfels (1927) has reported
the occurrence of chela-containing specimens of Ophlitaspongia
pennata from the Monterey Peninsula in California. These sponges
are believed to be identical to Axocielita hartmani.

SHAPE: The specimen is incrusting, measuring 30-35 mm in
thickness and covers an area of 20 square cm. No upright pro-
cesses are present.

CoLor: The living sponge is bright red in color. When pre-
served in alcohol, its color is drab.

CONSISTENCY: In both the living and preserved condition the
sponge is firm, almost brittle.

SURFACE: The surface of the sponge possesses numerous small]
pores which are irregularly shaped and randomly distributed. In
addition, there are larger depressions each of which is partially
covered by a thin translucent membrane. Some of the latter are
subspherical in shape while the remaining are elongate. These
larger depressions appear to be oscules (FIG. 1).

EcTOsoME: At the surface of the sponge are spicule plushes
usually formed of three or four thick styles standing erect. The
points of these styles protrude approximately 50 beyond the sur-
face. The heads of the styles are embedded in spongin fibers which
end at or just below the surface. Erect, thinner styles occur along
with the thick ones in some of the plushes. Thin and thick styles
are also present at the surface without any particular orientation.
There is no distinct class of spicules present only in the ectosome.

ENDOSOME: Basally there is a layer of spongin in contact with
the substratum. Ascending fibers, 50 to 70m in width, originate
from the basal layer and course upwards, ending at or just below
the surface. The ascending fibers are exceedingly thin and translu-
cent, and one gets the impression in viewing hand sections that

‘YPM — Peabody Museum of Natural History, Yale University, New
Haven, Connecticut.

FIG. 1. Surface view of the holotype of A xocielita hartmani n. sp.
The sponge is attached to a rock substratum. At a and at
b are areas from which tissue was removed for analysis.
Numerous small pores are just barely visible on the sur-
face. Oscules occur either within elongate depressions
(at c) or in subspherical depressions (at d). SGIEG:

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1966 New species of clathriid sponge

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FIG. 2. Spicule types present in Axocielita hartmani n. sp. A. Thick styles.
B. Thin styles. C. Toxas. D. Palmate isochelas. E. Microspination
present on the heads of thin styles. Scale I: A, B, C. Scale II: D, E.

there is very little spongin present. Thick styles lie partially em-
bedded in the ascending fibers and protrude, with pointed ends
out, at various angles from them. The ascending fibers are linked

dt Postilla Yale Peabody Museum No. 103

One to another by short spongin fibers which also contain thick
styles partially embedded within them. These cross bridges are
thin (20.0 to 50.0) and usually contain only one, two, or three
spicules. The bridges measure approximately 150 to 200, in length:
i.e., the length of one thick style. Randomly distributed through-
out the tissue of the sponge are thin styles, toxas, and palmate
isochelas. Rarely, thin styles are also found partially embedded
in the tracts of spongin fibers.

SPICULES: Two categories of megascleres and two of micro-
scleres are present in this species. The megascleres include two
categories of styles which can be distinguished on the basis of the
width of the spicule and on the presence or absence of microspina-
tion on the head of the spicule. Thick styles possess smooth heads
with no swelling. The shaft of thick styles is usually slightly curved.
Thin styles possess one to five minute spines on the head of the
spicule. In most cases the heads of thin styles are subtylote. The
microscleres include numercus palmate isochelas and less numer-
ous toxas. The morphology of the toxas is quite variable. They
are oxyote with a deep, rounded arch. Some, however, approach
a v-shape due to the height of the arch above the arms (see FIG. 2.)
Measurements of the four spicule types follow:

Thick styles: 156.0-177.8-228.8 X 11.9-15.7-19.0°
Thin styles: 130.0-1/54.9-193.4 X 4.8-5.9-10.2
Palmate isochelas: 19.0-2/.7-23.8
Toxas: distance

between tips

of arms: 27.3-69.3-121.4

height of arch

above arm tips: 11.1-20.7-43.1

DISCUSSION
In its skeletal features, Axocielita hartmani resembles Axo-
cielita linda de Laubenfels (1954, p. 156) described from the
Marshall and Caroline Islands. The latter species differs from
hartmani by growing as an exceedingly thin crust, by containing
two sizes of toxas, by possessing some contort palmate isochelas,
and by having tylostyles as megascleres.

* Measurements in microns. Means (in italics) and extremes of 25 spicules
in each category.

Nn

1966 New species of clathriid sponge

De Laubenfels (1927), in discussing a number of intertidal,
incrusting, red sponges from the Monterey Peninsula, California,
remarked on the variation in spiculation in Ophlitaspongia pen-
nata. He found some specimens which contained palmate isochelas
and others which lacked them; he designated both types of speci-
mens as pennata. The two forms cccur together on San Juan Island
as well and are strikingly alike in the field. Both have an incrusting
mode of growth and are red in color. Skeletal similarities include
the presence in both of smooth coring styles, toxas, anastomosing
spongin fibers, and thin interstitial and dermal styles. On the basis
of skeletal and field characteristics one might conclude, as did de
Laubenfels, that the two forms belong to a single species. How-
ever, in addition to the fact that A. hartmani has chelas and
O. pennata lacks them, there are marked cytological differences
between the two sponges (Simpson, in press). In these charac-
teristics the latter species bears a close relationship to Microciona
atrasanguinea Bowerbank (1862), the type species of Microciona.

The generic placement of hartmani is difficult. On the basis
of skeletal and cytological characteristics hartmani cannot be
placed in Ophlitaspongia, Microciona, or Thalysias (Simpson, in
press). Unfortunately, cytological data are lacking for the type
species of a number of additional genera (see Lévi, 1960) which
could include hartmani. I have decided to place hartmani in the
genus Axocielita (de Laubenfels, 1936, p. 118) at this time
because, on the basis of skeletal characteristics and growth form.
this new species fits into Axocielita better than into any other
previously established genus.

Hechtel (1965, p. 43-44) has argued that the type species of
Axocielita, Microciona similis Stephens (1915), should be restored
to the genus Microciona because it possesses spiny styles. He
furthermore states that the remaining species in Axocielita can
then be transferred to the genus Axociella Hallman (1920). If
this conclusion is accepted, hartmani would be placed in A xociella.
Because the type species of A xociella is a very distinctive, branch-
ing sponge with an axial core of spongin, quite unlike hartmani
(and also unlike Axocielita linda) 1 see no reason for dropping
Axocielita until additional non-skeletal data demand it. This means
that either Hechtel’s conclusion that the type species of A xocielita
actually belongs in the genus Microciona must be set aside for the

6 Postilla Yale Peabody Museum No. 103

time being, until additional characters are studied, or a new genus
must be established to receive hartmani as well as linda. I have
chosen the first course, the retention of Axocielita with similis as
the type species, until additional information is available. This
course is necessary since I have redefined the genus Microciona
on the basis of cytological features (Simpson, in press) and it is
inconsistent to return similis to Microciona without first having
cytological data. In addition, I have found (Simpson, in press)
that the presence of spiny styles is not correlated with the nature
of the special cell types.

Lévi (1960, p. 60) has expressed the opinion that in the
family Clathriidae it is superfluous to erect or retain separate
genera on the basis of the presence or absence of chelas alone.
However, in the case of Axocielita hartmani the presence of chelas
is associated with cytological characteristics distinct from those
found in Microciona pennata and therefore I have separated this
sponge from Microciona pennata at the generic level. Microciona
spinosa Wilson (1902) possesses the same skeletal features as
Axocielita hartmani, but the cytological features in this species
are like those in Microciona atrasanguinea, thus confirming Wil-
son’s original placement of the species in Microciona.

The latter finding reinforces a conclusion which can be drawn
from the present work: in the absence of additional characteristics
(histological and cytological) one has no basis for deciding
whether the presence or absence of chelas reflects an underlying,
more deeply rooted similarity or difference between species. There-
fore generic separations or mergers on this basis become a matter
of preference rather than a reflection of relationships. The present
work and that soon to be published elsewhere leads to the unhappy
conclusion that in some cases taxonomic decisions which are based
enly on skeletal characters and growth form are not indicative
of taxonomic relationship below the family level.

ACKNOWLEDGMENTS

I am indebted to Willard D. Hartman for his help and sugges-
tions in preparing this paper and have named the new species in
his honor. | am most grateful to Shirley G. Hartman who has
generously given her time and skill in preparing the spicule draw-

1966 New species of clathriid sponge 7

ing and to John Howard who prepared the photograph of the

holotype.

This work was generously supported by the National Science
Foundation (Grant GB-192 to Yale University) and by a Faculty
Research Fund Grant from Tufts University.

LITERATURE CITED

Bowerbank, J. S. 1862. On the anatomy and physiology of the Spongiadae.
Part Ill. On the generic characters, the specific characters, and on the
method of examination. Phil. Trans. Roy Soc. London 152: 1087-1135,
pl. 72-74.

de Laubenfels, M. W. 1927. The red sponges of Monterey Peninsula,
California. Ann. Mag. Nat. Hist., Ser. 9, 19: 258-267.

1936. A discussion of the sponge fauna of the Dry Tortugas in
particular and the West Indies in general with material for a revision
of the families and orders of the Porifera. Carnegie Inst. Wash. Publ.
No. 467, Pap. Tortugas Lab. 30: 225 p., 22 pl.

1954. The sponges of the West-Central Pacific. Oregon State
Monogr. Zool. no. 7: 306 p.

Hallman, E. F. 1920. New genera of monaxonid sponges related to the
genus Clathria. Proc. Linn. Soc. N.S.W. 44: 767-792.

Hechtel, G. J. 1965. A systematic study of the Demospongiae of Port Royal,
Jamaica. Bull. Peabody Mus. Nat. Hist. 20: 94 p., 8 pl.

Lambe, L. M. 1894. Sponges from the western coast of North America.
Trans. Roy. Soc. Can. 12(4): 113-138.

Lévi, Claude, 1960. Les Démosponges des cétes de France. I. Les Clathrii-
dae. Cah. Biol. Mar. 1: 47-87.

Simpson, T. L. In press. The application of histological and cytological
characteristics to the taxonomy of poecilosclerid sponges. Bull. Pea-
body Mus. Nat. Hist.

Stephens, Jane, 1915. Atlantic sponges collected by the Scottish National
Expedition. Trans. Roy. Soc. Edinb. 50: 423-467.

Wilson, H. V. 1902. The sponges collected in Porto Rico in 1899 by the
U.S. Fish Commission Steamer Fish Hawk. Bull. U.S. Fish Comm.
1900 (2): 375-411.

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