Postenterogonia orbicularis Faubel, 1983

Holleman, John J., 2007, Some New Zealand Polyclads (Platyhelminthes, Polycladida), Zootaxa 1560, pp. 1-17 : 2-3

Postenterogonia orbicularis Faubel, 1983

( Figures 1–3 )

Material

Thirteen specimens were collected under rocks from the North Island; three specimens from Echinoderm Reef, Leigh Marine Research Laboratory; five specimens collected by M. Larcombe at Whangateau Bay; and five specimens collected at Point Chevalier, Auckland.

Morphology

External features: The specimens were elongate ovals when moving and oval when at rest with the largest specimen measuring 49mm in length and 31 mm in width. Small eyes completely encircle the margin in a wide band anteriorly diminishing in width posteriorly. Tentacular eye clusters number 22 to 30 small eyes. Numerous small cerebro-frontal eyes form a fan like pattern from the behind the cerebral organ to the margin. The large centrally located pharynx has seven to ten pairs of lateral folds. The mouth is situated in the posterior half of the pharyngeal pocket.

Reproductive anatomy: The ventral lateral sperm ducts are thin walled becoming twisted and convoluted as they approach the penis turning dorsally uniting to form a muscular ejaculatory duct winding to the base of the penis. As the ejaculatory duct turns posteriorly and enters the penis a small blind sac extends anteriorly. The blind sac is a prostatic vesicle lined with glandular epithelia with long cilia. The conical unarmed penis is directed posteriorly in a vertically oriented male antrum leading to the male gonopore. The female gonopore is located at a distance posteriorly from the male gonopore. The female antrum ascends, expanding into the muscular vagina which curves anteriorly to a point just before the male gonopore then slants dorsally before it turns posteriorly. The lining of the vaginal duct has a spiral ridge from the ascent to the entrance of a short common oviduct which is formed by the union of the two oviducts. The vagina continues as a genito-intestinal canal opening into the intestine at a posterior level above the female gonopore.

Remarks

Faubel (1983) in his revision of the Polycladida created the genus Postenterogonia to separate Enterogonia pigrans var . novae-zealandiae Bock, 1925 from Enterogonia pigrans Haswell, 1907 on the basis of the presence of a coecal appendage with a prostatic function in Enterogonia pigrans var . novae-zealandiae. Hyman (1959a) confirms Haswell’s (1907b) description of Enterogonia pigrans stating that the male system lacks both a prostatic vesicle and seminal vesicle. Prudhoe (1982) designates the type-species as E. orbicularis ( Schmarda, 1859) Stummer-Traunfels, 1933 placing in synonymy Polycelis orbicularis Schmarda, 1859 ; Enterogonia pigrans Haswell, 1907 ; Enterogonia pigrans var . novae-zealandiae Bock, 1925; Enterogonia orbicularis Stummer-Traunfels, 1933 ; Enterogonia pigrans Hyman, 1959 a; Enterogonia orbicularis orbicularis Hyman, 1959 a and Enterogonia orbicularis pigrans Hyman, 1959 a. Prudhoe (1982) interprets Hyman’s (1959a) description of the male reproductive structures of Enterogonia pigrans stating that a small swelling of the dorsal wall of the ejaculatory duct where it turns ventrally to enter the penis-papilla is a free prostatic vesicle. Hyman’s (1959a) diagram of the reproductive system shows the ejaculatory duct expanding as it curves to enter the base of the penis-papilla. There is no indication of an anteriorly directed blind pouch with ciliated epithelium. Hyman (1959a) agrees with Haswell (1907b) that E. pigrans lacks both prostatic and seminal vesicles with the ejaculatory duct expanding as it enters the base of the penis- papilla. Faubel (1983) places E. orbicularis ( E. pigrans var . novae-zealandiae) in a new genus, Postenterogonia , separating the species E. orbicularis ( Schmarda, 1859) from E. pigrans Haswell, 1907 due to the absence of a coecal appendage in E. pigrans which has a prostatic function in E. orbicularis . The review of Hyman’s (1959a) description of E. pigrans leaves no question that it lacks a coecal appendage as she states “The male system is positively devoid of any indication of a prostatic vesicle and also lacks a seminal vesicle.” Based on the presence of a coecal appendage in E. orbicularis and its absence in E. pigrans Faubel (1983) is correct in separating the species and creating the genus Postenterogonia to include E. orbicularis and its various synonymies as Postenterogonia orbicularis .

Schmarda (1859) states that his specimens were from Chile, however Stummer-Traunfels (1933) indicates that there is evidence that they were collected in New Zealand. Haswell (1907b) is silent on the locality of E. pigrans however he states (1907a) that they were collected from Port Jackson, Australia. Bock’s (1925) specimens were collected from Ponui Island, Auckland, New Zealand. Hyman’s (1959a) specimens were collected intertidally from Long Reef north of Sydney, Australia. Postenterogonia orbicularis is known only from Auckland harbor north to Leigh Marine Research Laboratory of the north island of New Zealand while Enterogonia pigrans is known only from the greater Sydney harbor of Australia.

One specimen as a wholemount and another specimen with the anterior half as a wholemount and the posterior half as a set of sagittal sections have been deposited in the California Academy of Science, CAS Nos. 174731, 174332 and 174332 respectively.

Figures

FIGURES 1 – 3. Postenterogonia orbicularis. 1. Dorsal view. 2. Tentacular eyes, enlarged. 3. Sagittal view of copulatory complex.