Some New Zealand Polyclads (Platyhelminthes, Polycladida)
Author
Holleman, John J.
text
Zootaxa
2007
1560
1
17
journal article
10.5281/zenodo.178319
1e86106f-949f-4d58-87d6-89620b98c084
1175-5326
178319
Aotearoa
ballantinensis
n. sp.
(
Figures 13–15
)
Material
Specimens were collected from Echinoderm Flat west of Leigh Marine Research Laboratory; Island Bay Marine Laboratory, Wellington and Castle Point north island. Specimens from south island were collected from the Kaikoura and Portobello peninsulas.
Morphology
External features
: The specimens were cuneiform in outline, rounded anteriorly and tapering posteriorly. The largest specimen measured
23mm
long and
10mm
wide when moving. The dorsal surface is uniform medium yellowish brown shading to a reddish brown over the pharynx. The ventral surface is a pale light brown. The small marginal eyes form a wide band anteriorly that is reduced in width at the level of the pharynx continuing to completely encircle the rest of the margin. Small frontal eyes cover the area from the pharynx anteriorly. The tentacular eyes forming two distinct clusters, numbering 18 to 24, are located about half the distance from the cerebral organ to the margin. The large pharynx is about two thirds the length of the body with 8 major folds. The mouth is located in the posterior third of the pharyngeal pocket. The intestinal branches do not anastomose.
Reproductive anatomy
: The common gonopore, located in the posterior sixth of the body, leads to a short antrum that extends dorsally. The small unarmed penis papilla is at the apex of the antrum. The lateral thin walled sperm ducts progress posteriorly converging medially at the posterior end of the pharynx. There they are reduced to two small ducts that are surrounded with a thin layer of circular muscle cells. The ducts converge medially uniting into an ejaculatory duct that makes an “s” curve receiving the prostatic duct prior to entering the base of the penis. The cylindrical free prostatic is positioned horizontally with a lining of smooth epithelium surrounded with a muscular wall which contains gland cells. The vagina opens to the common antrum on its posterior aspect curving anteriorly to a point above the prostatic vesicle where it curves dorsally then posteriorly receiving the common oviduct. As the vagina externa curves anteriorly shell glands surround the vagina media. Prior to the vagina media curving dorsally the ciliated epithelial lining is in 6 or 7 spiral folds. The vagina media curves posteriorly receiving the common oviduct then continues as the ductus vaginalis. The ductus vaginalis has three or four radial folds shortly before turning ventral to the vaginal pore which is immediately behind the common gonopore.
FIGURES 13–15.
Aotearoa ballantinensis
. 13. Dorsal view. 14. Tentacular eyes. 15. Sagittal view of the copulatory complex.
Remarks
Aotearoa
ballantinensis
differs from the other genera of the family
Callioplanidae
in the combination of cerebral-frontal eyes; absence of tentacles; common gonopore; free cylindrical prostatic vesicle; absence of seminal vesicle and spermiducal bulbs; and the presence of a ductus vaginalis.
Hyman (1959b)
describes a new genus
Asolenia
and
Prudhoe (1982)
describes the genus
Ancoratheca
which are distinguished from the other genera of the family
Callioplanidae
by the presence of a common gonopore and antrum.
Aotearoa
ballantinensis
is different from
Asolenia deilogyna
Hyman, 1959
and
Ancoratheca australiensis
Prudhoe,
1982
in five major characteristics. First,
Aotearoa
ballantinensis
has a small blunt conical penis and
Asolenia deilogyna
Hyman, 1959
has an elongate penis with a thick muscular wall while
Ancoratheca australiensis
Prudhoe, 1982
has a small muscular penis that is armed with a short stylet. Second,
Aotearoa
ballantinensis
lacks a seminal vesicle while both
Asolenia deilogyna
Hyman, 1959
and
Ancoratheca australiensis
Prudhoe, 1982
have seminal vesicles with
A. australiensis
having a pair of spermiducal bulbs. Third, in
Aotearoa
ballantinensis
the female antrum opens on the posterior wall of the common antrum while in
Asolenia deilogyna
Hyman, 1959
and
Ancoratheca australiensis
Prudhoe, 1982
it opens on the roof of the male antrum. Fourth,
Aotearoa
ballantinensis
lacks a Lang’s vesicle but has a ductus vaginalis opening to the exterior a short distance posterior from the common gonopore.
Asolenia deilogyna
Hyman, 1959
lacks Lang’s vesicle but the vagina continues anteriorly as a paired uteri while in
Ancoratheca australiensis
Prudhoe, 1982
has a Lang’s vesicle which opens to the ventral surface through a small pore that is a short distance posterior to the common gonopore. A fifth characteristic that distinguishes
Aotearoa
ballantinensis
from
Asolenia deilogyna
Hyman, 1959
and
Ancoratheca australiensis
Prudhoe, 1982
is the distribution and pattern of frontal, marginal and tentacular eyes.
Aotearoa
ballantinensis
has frontal eyes that cover the area from the pharynx anteriorly, marginal eyes that encircle the margin and tentacular eye clusters.
Asolenia deilogyna
Hyman, 1959
has tentacular and cerebral eyes while
Ancoratheca australiensis
Prudhoe, 1982
has small marginal eyes on the anterior third of the margin, frontal eyes in a fan pattern anterior to the cerebral organ and tentacular eye clusters.
Aotearoa
ballantinensis
is very common in
New Zealand
occurring on both of the large islands. It differs from the other genera of the
Stylochidae
in the combination of cerebral-frontal eyes; absence of tentacles; common gonopore; free cylindrical prostatic vesicle; absence of seminal vesicle and spermiducal bulbs; and the presence of a ductus vaginalis. A stained wholemount has been designated the
holotype
, an unstained wholemount and a set of serial sagittal slides are designated as
paratypes
and have been deposited with the California Academy of Science, CAS Nos. 174341, 174342 and 173083 respectively.
Etymology
The genus name
Aotearoa
is Maori for
New Zealand
. The new species is named for Dr. William Ballantine in recognition of his efforts in establishing Marine Reserves in
New Zealand
.