Chromoplana kaikouris, Holleman, John J., 2007

Holleman, John J., 2007, Some New Zealand Polyclads (Platyhelminthes, Polycladida), Zootaxa 1560, pp. 1-17 : 14-16

Chromoplana kaikouris n. sp.

( Figures 23–25 )

Material

Thirteen specimens were collected from a holdfast of the kelp Lessonia variegata in Kaikoura Harbor.

Morphology

External features: The body is an elongate oval. The largest individual measured 4.8 mm. long and 1 mm. wide. Tentacles are absent. The sucker is posterior to the middle. The background is translucent white with tiny white maculae scattered over the dorsal surface with the gut and reproductive apparatuses appearing cream colored. There are four greenish blue stripes running longitudinally and a greenish blue patch anterior to the cerebral eyes which does not extend to the margin. The two lateral most stripes appear to originate from the anterior greenish blue patch while the two medial stripes begin immediately posterior to the cerebral eyes. As the four stripes extend posteriorly the two medial stripes fuse with the nearest lateral stripe at a point about seven-eighths of the length and then the two resulting stripes fuse tapering to a point just prior to the posterior margin. The marginal eyes number between two and six and are restricted to the anterior margin. There are two groups of cerebral eyes numbering three each. Two eyes of each cerebral group are located near the dorsal surface while the third eye is located on the dorsal aspect of the brain and is directed ventrally. The large heavily folded pharynx is located in the anterior half of the body. The mouth is situated posterior to the mid point of the pharyngeal pocket.

Reproductive anatomy: The male apparatus is located below the posterior end of the pharynx. The sperm ducts lead anteriorly and curve medially joining together forming a common sperm duct which is inflated to form a spherical spermiducal vesicle. The spermiducal vesicle is in contact with the posterior wall of the muscular seminal vesicle and opens directly into the seminal vesicle. The seminal vesicle is rounded posteriorly and tapers anteriorly to enter the prostatic vesicle. The prostatic glands are extravesicular and small ducts can be seen to enter across the wall of the prostatic vesicle. The prostatic vesicle is rounded posteriorly and tapers anterior-ventrally entering the base of the short, moderately muscular, unarmed conical penis papilla. The penis fills the male antrum with the male gonopore opening a short distance behind the mouth. The dorsal wall separating the male antrum from the pharyngeal cavity is very thin. The female gonopore is a short distance behind the male gonopore and opens into a short female antrum which expands into a flat, expanded cement pouch. Cement glands surround the cement pouch. The vagina continues dorsally from the cement pouch. The uteri were not observed. Numerous large eggs were observed in the posterior half of the body.

Remarks

Chromoplana kaikouris is distinctive by its color pattern and small number of marginal eyes.

One wholemount has been designated the holotype and has been deposited with the National Museum of New Zealand NMNZ ZW No. 1453. One wholemount with two specimens and a set of serial sagittal sections are designated paratypes and have been deposited with the National Museum of New Zealand, NMNZ ZW No. 1454 and No. 1455 respectively. Three wholemounts and a set of serial sagittal sections are designated as paratypes and are deposited with the California Academy of Science, CAS Nos. 107339, 107340, 107341, and 107342 respectively.

Etymology

Named for Kaikoura, New Zealand where it was collected.

Remarks

Bock (1922) described the family Chromoplanidae including two monotypic genera Chromoplana and Amyella . Corrêa (1958) added the genus Chromyella . Chromoplana bella is distinguished from the other two species of the family by a large interpolated prostatic vesicle, the presence of a spermiducal vesicle and reduced number of cerebral eyes. The cerebral eyes of Chromoplana bella consist of three pair, two pair close to the dorsal surface with the third pair located immediately above the brain and directed ventrally. Faubel (1984) separated the genera Amyella and Chromyella from the family Chromoplanidae based on the absence of a prostatic vesicle in Amyella and Chromyella placing them in the family Amyellidae . The family Chromoplanidae and genus Chromoplana were retained with the genus having the characteristics of the family. Prudhoe (1985) retained the three genera in the family Chromoplanidae distinguishing the genera based on the position of the mouth and male and female gonopores. Faubel’s (1984) revision is preferred as it places importance on the male reproductive system and then on the position of the mouth and gonopores. The three species of the genus Chromoplana , Chromoplana bella Bock, 1922 , Chromoplana sirena and Chromoplana kaikouris , can be distinguished by their dorsal color patterns. Chromoplana bella Bock, 1922 has four longitudinal brown stripes with the two lateral most bands joining together anterior to the brain leaving a clear notch at the anterior end. The two medial stripes are narrower and begin a short distance behind the brain. Chromoplana sirena has two longitudinal brown stripes that taper posteriorly joining together near the posterior margin and a yellow transverse stripe anterior to the cerebral eyes. Chromoplana kaikouris has four longitudinal greenish blue stripes with an anterior patch rounded anteriorly. The longitudinal stripes narrow as they extend posteriorly with the two interior stripes fusing with the more lateral stripes which continue posteriorly uniting prior to the posterior margin. The structure of the male reproductive system is almost identical in the three species with a few differences. Chromoplana bella Bock, 1922 and Chromoplana sirena have a penis with a penis sheath which is lacking in Chromoplana kaikouris . Bock (1922) describes and illustrates short ducts, one a continuation of the sperm duct between the spermiducal vesicle and the seminal vesicle and the second the ejaculatory duct between the seminal vesicle and the prostatic vesicle. The short ducts were not observed in Chromoplana sirena and Chromoplana kaikouris . Bock (1922) did not observe uteri in Chromoplana bella Bock, 1922 and they have not been located in Chromoplana sirena and Chromoplana kaikouris .

Figures

FIGURES 23 – 25. Chromoplana kaikouris. 23. Diagram of the dorsal color pattern. 24. Dorsal view. 25. Sagittal view of copulatory complex.