Occasional papers of the California Academy of Sciences

OCCASIONAL PAPERS

OF THE

California Academy of Sciences

No. 78, 9 pages, 17 figures. October 22, 1969

Three New Species Of Burrowing Bryozoans
(Ectoprocta) From The Hawaiian Islands

By

John D. Soule and Dorothy F. Soule

Allan Hancock Foundation, University of Southern California,
University Park, Los Angeles, California 90007

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SAN FRANCISCO

PUBLISHED BY THE ACADEMY

1969

OCCASIONAL PAPERS

OF THE

CALIFORNIA ACADEMY OF SCIENCES

No. 78, 9 pages, 17 figures. October 22, 1969

Three New Species Of Burrowing Bryozoans
(Ectoprocta) From The Hawaiian Islands

By

John D. Soule^ and Dorothy F. Soule-

Abstract: Recent collecting in the waters off the Hawaiian Islands under the
auspices of a National Science Foundation Grant GB 5208, has produced the first
records of penetrating bryozoans in the mid-Pacific. Two are known species:
Penetrantia parva, described from New Zealand (Silen, 1946), and Immergetxtia
zelandica minuta Soule, 1950, described from Zamboanga, Philippine Islands. Three
new species are included in this report: Terebripora varians, Penetrantia operculata,
and Immergentia angidata.

Introduction

D'Orbigny first described the tracings on molkisk shells made by bur-
rowing bryozoans, and erected the genus Terebripora in 1847. but it was not
until the work of Marcus (1938) that the anatomy of the zoids became known.
Marcus (1938) reported one of d'Orbigny's species, Terebripora ramosa, in
Brazilian waters that had first been described from Chile and Peru. Two new-
genera and twelve new species have since been described and the anatomy of the
zoids figured (Silen, 1946, 1947; Soule, 1950a, 1950b; Soule and Soule, 1968).

Past distribution records, although sparse, suggest that the species may be
widely distributed. For example, Bobin and Prenant (1954) found Terebripora
comma Soule, 1950, described from California, in the Mediterranean. Soule

1 Research Associate, Allan Hancock Foundation, University of Southern California, Los Angeles, and
American Museum of Natural History, New York.

2 Research Associate, Allan Hancock Foundation, University of Southern California, Los Angeles, and
Moore Laboratory of Zoology, Occidental College, Los Angeles, California.

CALIFORNIA ACADEMY OF SCIENCES

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Figure 1. P enetrantia parva S\\cn; -dutozoid.
Figure 2. Penetrantia operculata, new species; autozoid with knobbed operculum.

No. 78] SOVLE & SOULE: XEW SPECIES OF HAWAIIA.X HRVOZOANS 3

found Penetrantia concharum and Pcnctrantia densa, described originally from
Sweden and South Africa respectively, in California waters (Soule, 1950). A
new species, Tercbripora cltaninac Soule and Soule, 1968, was recently described
from the Antarctic, inhabiting Ccphalodiscus.

The authors wish to express their appreciation to James McVey, Stanley
Swerdloff, and Greg Stanton, of the Department of Zoology, University of
Hawaii, whose efforts were responsible for the collection of the bryozoans re-
ported in this paper. We also wish to thank Mr. James Smola for his assistance
in the preparation of serial sections.

Methods and Materials
Gastropod shells showing the surface tracings of burrowing bryozoans were
immediately fixed and preserved in neutral formalin when collected in the field.
Transported to the laboratory, the gastropods were identified and examined wet
under a dissecting microscope. Each specimen was given an identifying number
and carefully broken into small fragments. The fragments were examined wet
and some fragments were air-dried to preserve a record of the surface traces
while the remainder were decalcified in 5 percent trichloracetic acid, then washed
in several changes of tap and distilled water, and stored in 70 percent ethanol.
Some of the decalcified material was then stained with azo-carmine, dehydrated,
and mounted for anatomical studies. The remaining decalcified material was
dehydrated, imbedded in paraffin and serial sections were cut at 3-4 microns.
These were stained with hematoxylin and eosin, and examined histologically as
well as for accurate tentacle count.

Systematic Accounts
Genus Penetrantia Silen, 1946

Penetrantia parva Silen, 1946.

(Figure 1.''')

Penetrantia parva Silen, 1946, pp. 4-5, fig. 7.

The Hawaiian specimens agree in all respects with Silen's description. The
autozoids range in length from 400 to 440 microns, and are pointed proximally.

3 A, apertural muscles; B, brown body; C, cardia; D, degenerate polypide; E, ovum or embryo; G,
gizzard; I, intestine; O, operculum; P, parietal muscles; R, retractor muscles; S, stomach; T, tentacles;
V, vestibule; W, wall of embryo chamber.

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Figure 3. P. operculata, new species; gonozoid showing separate embryo chamber with
ovum and with stolon attached. Operculum is freed from aperture and lies in embryo
chamber when polypide degenerates.

Figure 4. P. operculata, new species; aperture in shell, with aperture of zoid beneath
shell surface. Note knobbed operculum, central denticle (lyrula), and lateral denticles
(cardelles).
Figure 5. P. operculata, new species; gonozoid showing attachment of embryo chamber.

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No. 78] SOULE & SOULE: NEW SPECIES OF HAWAIIAN BRYOZOANS S

The gonozoids are short; 210 to 220 microns in length, with the tip of the
degenerate polypide extending below the embryo chamber.

Occurrence. Pokai Bay, 0.5 miles off Waianae, Oahu; depth 25 feet.
Collected 26 July 1967 in shell of Conus species. Off Naue, Kauai; depth 30
feet, water temperature 80°F., in shell of Conus ebraeus.

Penetrantia operculata Soule and Soule, new species.

(Figures 2, 3^ 4, 5, 12, 13.)

Material. Holotype, Allan Hancock Foundation bryozoan number 150.
Paratype, Allan Hancock Foundation bryozoan number 150.1.

Diagnosis. Burrowing colonial ectoproct bryozoans with the autozoids
and gonozoids connected by "stolons." Autozoids elongated, cylindrical,
bluntly rounded proximally, and with the aperture closed by a massive knobbed
operculum. Tentacle number is 12. Gonozoids short, the degenerate polypide
curled around under the embryo chamber.

Description. The colonies of Penetrantia operculata consist of feeding
autozoids and numerous reproductive gonozoids. The mature functional feeding
autozoids measure from 450 to 500 microns in length, and 100 to 110 microns
in width. Each autozoid possesses a polypide bearing 12 tentacles and a
typical U-shaped digestive tract. The digestive tract is provided with a small
gizzard opening into the stomach. The muscular system consists of the retractor
muscle group, scattered parietal muscle fibers, and the apertural muscle group.
The aperture is closed by a distinctive thick operculum. Each operculum is
provided with a centrally placed, raised knob.

The gonozoid is short, measuring 220 to 230 microns in length. It has a
bulbous embryo chamber containing the ovum and a polypide that is curved,
curling proximally under the reproductive body. The musculature and the
polypide retrogress and are non-functional. The operculum is conspicuous,
loosely associated with the degenerate polypide mass.

The openings on the surface of the mollusk shell, produced by the zoids of
Penetrantia operculata are well spaced, almost circular, with a blunt projection
extending into the opening from the lower rim. The aperture of the zoid proper

<-

Figure 6. Terebripora varians, new species; normal zoid.
Figure 7. T. varians, new species; zoid in reproduction, with degenerate polypide,
developing ovum, and brown body.

Figure 8. T. varians, new species; a, b, c, d, e, showing variety of stolon attachments
on individuals.

Figure 9. Immergentia zelandicaminutaSoxiXe; norrazlzoiA.
Figure 10. Immergentia angulata, new species; zoid angled away from viewer. Note
size as compared with Immergentia zelandica minuta.

Figure 11. /. angz^/aia, new species; zoid in reproduction.

CALIFORNIA ACADEMY OF SCIENCES

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Figure 12. Penetrantia operculata, new species; apertures in shell, X 25.
Figure 13. P. operculata, new species; apertures in shell, showing submerged zoid
aperture with median denticle and cardelles, operculum with knob, X SO.

Figure 14. Terebripora varians, new species; irregular shell apertures and stolon
traces, X 25.

Figure 15. T. varians, new species; irregular apertures in shell, X 50.
Figure 16. Immergentia angulata, new species; apertures in shell and stolon traces, X 25.
Figure 17. /. angulata, new species; ovoid apertures in shell and short stolon traces, X 50.

No. 78] SOULE & SOULE: NEW SPECIES OF HAWAIIAN BRYOZOANS 7

lies below the shell surface and bears a prominent median denticle (lyrula), as
well as lateral hinge denticles (cardelles) for articulation of the operculum. The
stolonal tracings form an indistinct, irregular meshwork. The surface markings
are similar to those of Penetrantia concharum, as illustrated by Silen, 1947
(fig-1).

Penetrantia opercidata differs from previously described species in that
each of the autozoids possesses the thick, knobbed operculum, and the gonozoid
bears the non-functional polyjDide flexed, curving under the embryo chamber.
Autozoids of P. operculata, new species, P. densa Silen, 1946, and of P. brevis
Silen, 1946, all have 12 tentacles.

Occurrence. Haena Bay, Kauai; collected 1 July 1967, depth 20 feet,
water temperature 80°F. In shell of Conus striatus.

Genus Terebripora d'Orbigny, 1847

Terebripora varians Soule and Soule, new species.

(Figures 6', 1\ 8a-e, 14, 15.)

Material. Holotype, Allan Hancock Foundation bryozoan number 151.
Paratype, Allan Hancock Foundation bryozoan number 151.1.

Diagnosis. Stolonate, burrowing colonial Ectoprocta, with cylindrical
zoids that taper to a narrow proximal end. The zoids are connected by short
multiple secondary stolons that join the elongated primary stolons. There are
1 1 tentacles.

Description. Colonies stolonate, possessing lengthy primary stolons which
have internodes placed at irregular intervals so that the stolonal segments are
of variable length. The primary stolons anastomose to form an extensive mesh-
work. A notable feature of this species is the presence of multiple secondary
stolons, up to 4 in number, which arise from diverse localities on a single zoid
and unite with the primary stolon. The stolonal diameter ranges from 10 to 15
microns.

The polypide includes a digestive tract with a prominent grinding organ, or
gizzard, and bears a circle of eleven tentacles. The musculature consists of the
apertural group, the parietals, and the retractor group. The length of the func-
tional zoids ranges from 370 to 400 microns, with the width from 60 to 75
microns. Many of the zoids possess one or more small ^'brown bodies." Zoids in
reproduction were scarce: two were found, each with a rounded ovum and a
degenerated polypide.

Surface tracings on the moUusk shell formed by the zoid apertures and
stolons of Terebripora varians are not distinctive. The openings are well spaced,
and are irregularly ovoid. The stolons produce a faint mesh-like trace among
and connecting the rounded perforations.

Terebripora varians differs from other species of Terebripora with known
anatomy in the possession of multiple secondary stolons which arise from varying

8 CALIFORNIA ACADEMY OF SCIENCES [Occ. Papers

anatomical areas on the zoid. It is this character that provides its name. The
zoids of Terebripora varians are larger than those of T. comma and T. ramosa,
but smaller than those of T. eltaninae. Terebripora varians has 11 tentacles,
T. comma has 8 tentacles, T. ramosa has 12 tentacles, and T. eltaninae has 10
tentacles.

Occurrence. Haena Bay, Kauai; collected 1 July 1967, depth 20 feet,
water temperature 80°F., in shells of Conus striatus. Off Keaukaha, Hilo,
Hawaii; collected 15 July 1967, depth 25 feet, water temperature 81 °F., in
shells of Conus species?.

Genus Immergentia Silen, 1946

Immergentia zelandica minuta Soule, 1950.
(Figure 9'.)

Immergentia zelandica Silen var. minuta Soule, 19S0, p. 367, fig. 6.

Colonies with small zoids, ranging in length from 210 to 250 microns,
slightly longer than those from the Philippine Islands. A distinct, finger-like
projection is present, forming the proximal extremity. There are 9 tentacles.
A number of zoids with an ovum and degenerate polypide were present.

Occurrence. Haena Bay, Kauai; collected 1 July 1967, depth 20 feet,
water temperature 80°F., in shells of Conus striatus and Cypraea species?.

Immergentia angulata Soule and Soule, new species.

(Figures 10, 11, 16, 17.)

Material. Holotype, Allan Hancock Foundation bryozoan number 152.
Para type, Allan Hancock Foundation bryozoan number 152.1.

Diagnosis. Colonial, stolonate burrowing ectoproct bryozoan. Zoids ex-
tremely small, acutely curved at the distal end below the aperture, and tapering
to a pointed proximal termination. The tentacle number is 8.

Description. Colonies are stolonate, with the zoids joined by an irregular
anastomosing meshwork of delicate hollow stolons having a diameter of 7-8
microns. Functional zoids are short, ranging from 180 to 200 microns in length
and 50 to 55 microns in width. The zoids characteristically are bent acutely in
the distal region immediately below the junction of the apertural region with
the stolon. The proximal extremity is tapered to a point. In functional zoids
the polypide is U-shaped. There are 8 tentacles. "Brown bodies" are present
in many of the zoids. The musculature consists of a well developed retractor
group, parietals, and an apertural group. Zoids with developing ova and a
degenerate polypide were scattered among the feeding zoids. The musculature,
especially in the retractor group, shows evidence of hypertrophy in the zoids
with reproductive bodies.

The openings made by the zoids are very small. They are ovoid, narrowing
toward the thread-like trace made by the stolon. The openings are well spaced.

No. 78] SOVLE & SOULE: NEW SPECIES OF HAWAIIAN BRYOZOANS 9

They offer no special characteristics that would distinguish them from other
species of Immergcntia or even from Terebripora.

Immergentia angulata possesses zoids that are the smallest of any that have
been described, and are the only ones to show the acute bend at the distal end.
Also, in having 8 tentacles, /. angulata differs from Immergentia calijornka
Silen, 1946 and /. philippinensis Soule, 1950, which have 10 tentacles, and /.
siiecica Silen, 1947, /. zelandica Silen, 1946, and /. zelandica minuta Soule, 1950
with 9 tentacles.

Occurrence. Keaukaha, Hilo. Hawaii; collected 15 July 1967, depth 45
feet, water temperature 81 °F., in shell of Pisantu tritonoides.

LITERATURE CITED

BoBiN, Genevieve, and Marcel Prenant

1954. Sur un Bryozoaire perforant (Terebripora comma Soule), trouve en Mediterranee.
Archives de Zoologie Experimentale et Generale, tome 91, no. 3, pp. 130-144.
Marcus, Ernst

1938. Bryozoarios perfuradores de conchas. Arquivos do Instituto Biologico, vol. 9,
art. 25, pp. 273-296.
D'Orbigny, Alcide D.

1847. Zoophytes. Voyage dans L'Amerique Meridionale, vol. 5, pt. 4, Bryozoaires,
pp. 7-23.
Silen, Lars

1946. On two new groups of Bryozoa living in shells of Mollusks. Arkiv for Zoologi,

bd. 38B, no. 1, pp. 1-7.

1947. On the anatomy and biology of Penetrantiidae and Immergentiidae (Bryozoa).

Arkiv for Zoologi, bd. 40A, no. 4, pp. 1-48.
Soule, John D.

1950a. Penetrantiidae and Immergentiidae from the Pacific (Bryozoa; Ctenostomata).

Transactions of the American Microscopical Society, vol. 69, no. 4, pp. 359-367.
1950b. A new species of Terebripora from the Pacific (Br\^ozoa, Ctenostomata). Journal

of the Washington Academy of Sciences, vol. 10, no. 11, pp. 378-381.
Soule, John D., and Dorothy F. Soule

1968. A new species of Terebripora (Ectoprocta, Ctenostomata) from Antarctic Cephalo-

discus. Bulletin Southern California Academy of Sciences, vol. 67, no. 3, pp.

178-181.

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